HUP0200780A2 - Apparatus and method for distribution of high quality image and audio programs to remote locations - Google Patents

Description

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EQUIPMENT AND PROCEDURE HIGH QUALITY PICTURE AND SOUND PROGRAMS

FOR DISTRIBUTION TO REMOTE LOCATIONS

The invention relates to electronic audiovisual signal processing. More specifically, the invention relates to an apparatus and method for distributing digitized still or moving images and audio information for presentation at various locations. The invention also relates to the encoding, encryption, transmission, storage, decompression, and decryption of high-precision electronic audiovisual programs originating from a central device, and their playback by means of various projection and presentation systems.

For decades, the motion picture industry was based on the copying, distribution, and projection of celluloid films. This allowed a variety of creative programs to be presented in geographically dispersed movie theaters across the country and the world. The methods and mechanisms of film distribution have remained largely unchanged over the decades.

The current method of copying and distributing films is illustrated in Figure 1. The basis for copying films is usually an exceptionally high-quality camera negative. After the original film has been produced, a so-called master copy is made in 50 film studios 52 during preparation (laboratory). From the master copy, a so-called distribution negative is produced using 54 film copying equipment, from which a large

- 2 distribution copies (so-called positives) are made. Depending on the number of distribution copies required, several intermediate steps may be used, and several copies may be made within each step. The positive copies are delivered by courier or otherwise to the various movie theaters 56 (for the sake of simplicity, only one of these has been shown). In the movie theater 56, the work is presented in such a way that individual frames of the film are projected onto a display surface (projection screen) by means of a projector 58. In this conventional method, a multi-track audio program is usually produced using an audio editing system 51, which is recorded on the film tape together with the frames of the film. The recorded audio program is played back by the movie theater's sound reproduction system 57 in synchrony with the film projection system.

The distribution method shown in Figure 1 has proven itself well in practice, but it also has some inherent shortcomings. One is that the celluloid material of the film and the limited bandwidth of the film carrier do not allow the recording of multi-channel, high-quality audio programs. Another shortcoming is that the production of a large number of copies is very expensive. Another shortcoming is that the delivery of the boxes containing the film copies to the many movie theaters is a time-consuming and expensive task. In addition, the number of so-called multiplex movie theaters, in which films are shown in several rooms arranged within a building, and different films are shown simultaneously in each room.

The large number of copies makes it increasingly difficult to prevent illegal copying and theft of materials. The film industry loses billions of dollars annually due to so-called pirated copies and theft. In addition, the quality of copies deteriorates over time due to dust, wear, heat and other known factors. It should also be mentioned that film materials must be destroyed over time, which also entails costs.

New technologies offer alternative solutions to film distribution problems. For example, the development of digital technology enables revolutionary new distribution concepts, as individual works can now be stored in digital form, electronically, eliminating the need for films carrying optical information. Digitized images can be distributed on various magnetic media or compact optical discs, or transmitted via wired, fiber-optic, wireless or satellite communication systems.

However, alternative distribution techniques, including digital methods, have not been able to provide the same quality and clarity as celluloid film. The techniques used are generally based on audiovisual (AV) signals recorded on various magnetic or optical media and displayed on video monitors, television screens or projectors. These techniques cannot match the quality of the film due to limited bandwidth.

- Produce 4 matching images.

Although satellite transmission methods exist, they are not economically suitable for the distribution of high-quality AV material. Since the distribution of films can essentially be considered a special case of broadcasting on a continental scale, the satellite distribution method and the advantages of large-scale broadcasting that come with it could ultimately make the latter suitable for the distribution of films. However, the transmission of a very high-quality AV signal in “real time” would require a data rate of about 1.5 billion bits per second. At such a data rate, the transmission of a single program would require the entire capacity of a satellite, which would make distribution prohibitively expensive. In addition, the display of the received information would require a special quality of projector that has not been available until now.

In order to reduce the data rate required for the distribution of high-quality electronic images, various compression algorithms have been developed. One digital dynamic image compression technique that provides a significant degree of compression while preserving the quality of the image signals uses adaptively sized blocks and subblocks consisting of coded discrete cosine transform (DCT) coefficients. This method is referred to as the ABSDCT (adaptive block size discrete cosine transform) method. The adaptive block sizes are obtained in such a way that

- 5 for selection, in order to exploit the information redundancies within the frames of the image data. This method is described in US-PS 5,021,891, the contents of which are incorporated herein by reference. Information on DCT methods is also disclosed in US-PS 5,107,345, the contents of which are also incorporated by reference. The combination of the ABSDTC method with the so-called discrete quadtree transformation is described in US-PS 5,452,104, the contents of which are also incorporated by reference. The systems described in these patents employ intra-frame coding, whereby each frame of an image sequence is coded without regard to the content of subsequent frames.

ABSDCT can reduce the required data rate from approximately 1.5 billion bits/s to approximately 50 million bits/s without any noticeable loss of quality. The data compressed in this way can be transmitted at an acceptable cost using a single transponder on a satellite, especially since this single transmission can be received by hundreds or thousands of cinemas within a given geographical region or country.

The distribution of films in digital electronic format allows for quick and cheap copying of films without loss of quality. In addition to the ease of copying that digital technology provides, there are also encryption (coding) methods available to prevent unauthorized copying.

- Valuable information should reach up to 6 people.

New techniques such as the ABSDCT compression method, modern projection equipment and electronic coding processes make it possible to create "digital cinema systems". Digital cinema generally means a system in which high-quality film recordings are converted into a digital electronic format for storage, transmission and presentation, and in this format are distributed and shown electronically. Digital cinema can eliminate many of the shortcomings of the current film distribution process. The use of satellite transmission greatly reduces the cost of copying and distributing films. In the case of the digital system, unlike the case of celluloid film, there is no deterioration in quality over time. The digital system can be used to prevent illegal copying and theft of films, and security measures can be implemented in the digital system itself. Despite all this, the motion picture industry and related industries have not yet developed complete digital cinema systems.

Many questions and problems remain to be solved. The new digital motion picture systems require improved forms of protection to prevent unauthorized removal of films from movie theaters. Multiplex movie theaters, which screen films in multiple rooms, are trying to maximize their investment and are therefore developing increasingly complex screening schedules.

- 7 are created and a given film is shown in more and more places. This requires providing many electronic copies to movie theaters using traditional technology, which further complicates the distribution system and increases costs.

The current distribution channels and mechanisms are structured by the older celluloid film copying and distribution techniques described above. To fully exploit the benefits of the proposed new digital film distribution method, new techniques and new equipment are needed to reduce the number of copies required, to allow new films to be released as quickly as possible and to update existing films, to provide more flexible distribution at reasonable costs, and to allow for a more concentrated schedule. At the same time, film producers, film studios, and cinema managers want to exercise greater central control over film release and distribution, and to expand their activities into new markets. For example, it would be desirable to distribute films and other audiovisual productions using alternative audio channels in order to reach multilingual and non-lingual audiences at lower cost.

There is therefore a need to integrate certain technologies into a system and process suitable for providing and organizing high-quality video and audio programs to be presented on large projectors. A system and

- 8 methods are needed to reliably transmit high-quality video and audio signals to designated movie theaters, flexibly schedule various movies and advertisements, incorporate high-quality audio signals, and incorporate appropriate security measures. The present invention satisfies these needs as described below.

The present invention relates to a system and method for electronically distributing high quality video and/or audio programs from one or more central facilities to one or more presentation locations or movie theaters. In the case of the apparatus and method according to the invention, the video and audio information (usually representing a sound film or similar production) is encoded and encrypted at a central station, the material is then distributed over a wide geographical area, and the program is stored in one or more rooms or presentation locations, or displayed on a large screen or projection screen. The program (program material) generally consists of a moving image and synchronized audio recording and/or other related information. Such related information may, for example, be a special visual signal channel for the visually impaired, subtitles for audiences speaking other languages and/or hearing impaired, or a multimedia channel.

The program can be long (for example, in the case of feature films) or short (for example, in the case of clips or so-called trailers), and it can also be a still image (for example, advertisements or announcements).

- 9). Audio programs and related programs are not always synchronized with the picture information. For example, background music does not require synchronization.

The information representing the program is processed by the central station for distribution purposes. A source generator system, located at the central station or elsewhere, generates electronic audio and video signals from an analog or digital input signal. The source generator system typically uses a television projector to generate the electronic video signals, while a voice recorder is used to generate the electronic audio signal. The electronic signal may also be derived directly from an electronic camera or other electronic source (such as a computer-based image processing system).

The electronic image and sound signals are then processed by a compression-encryption system. The compression-encryption system can be installed locally both at the central station and at another suitable location (for example, in a film studio). The compression is performed using a known dynamic compression technique. The compressed signal is transmitted to the designated locations via a wired, optical fiber, wireless or satellite communication system. The audio signal can be compressed using a standard digital audio compression algorithm.

Encryption is performed using time-varying electronic key values and/or digital checkword sequences that are only available to authorized users. In addition, the image signal and/or

- 10 Audio signals may also be associated with a digital signature or "watermark". A watermark is a visual identifier that is assigned to a specific movie theater and/or a specific time period and that is not visible to the general viewing public, but which can be used to determine whether the copy was legally placed at the location when the program is not played in real time or in a still image mode. The information required to decrypt the image and/or audio information is generated by individual decryption units using secret unique keys and security information sent to the specific presentation location. The decryption of the image and audio signals is usually done separately. By treating the image and audio parts as separate programs, different audio programs can be associated with the image programs for various purposes (for example, due to language differences).

The compressed and encrypted signals are fed into a modulation-transmission system at the central station or stations. During the modulation-transmission process, forward error correction information is added and the data stream to be transmitted is modulated. Transmission is usually via satellite, but terrestrial cable, fiber optic, or wireless methods can also be used. The transmission rate of the broadcast can be varied so that the information is transmitted at a rate lower than, higher than, or equal to the compression data rate. The transmission of live programs is supported by the system if the data transmission is at a rate corresponding to the compression rate.

The central station also includes a network management system. The network management system, for example, uses control processors to control the operation of the entire system, i.e. broadcasting, playback and display, the implementation of security measures, and to monitor and supervise the system and the network. The system is suitable for fully or partially automated central or distributed control, or manual intervention.

The program material and additional control information are broadcast to the systems of the exhibition venues under the control of the network management system. Although the movie theater networks are capable of receiving all broadcast programs, they selectively store only those programs that are broadcast to them from the received programs. The control methods used in the system allow the movie theater networks to identify individual programs and to selectively store the received programs.

In a movie theater network, a receiver-demodulator unit receives the broadcast program. Satellite signals are usually received using a satellite dish. The receiver-demodulator demodulates the received signals and performs error correction on the demodulated signals. The demodulated signal, together with the results of the error correction, is sent to the movie theater control system, usually in the form of a transmitted data packet stream.

- 12 The theater control system checks the demodulated signal for errors and requests retransmission of any defective signal portions. The theater control system requests retransmission by transmitting a communication signal associated with the return link (from the theater system to the central station(s). The return link may be established via a telephone network, satellite channel, the Internet, or other low-data-rate communication channel.

In addition to the control of the movie theater control system, the movie theater network storage units centrally store the program material on site. The storage units may be solid-state, magnetic, or optical storage devices and may store multiple programs simultaneously. The central storage system is connected to the individual presentation locations via a local area network (electronic or optical) such that any authorized presentation location (e.g., projector) may play and present any program. It is also possible for the same program to be played simultaneously by two or more presentation locations. The program material is delivered from the storage units to the designated presentation rooms via a local area network (LAN). The local area network may consist of various LAN architectures. In this description, reference is made to a LAN network having a central network switch architecture, but other LAN networks may be used in the system of the invention.

During playback, the projection room displays the

- Processing of 13 program materials. Signal processing includes data rate decompression (decompression) and decryption (decryption, extraction). The decompression and extraction algorithm to be used depends on the compression and encryption technique used by the central station. The decompressed and extracted image signal is displayed in the projection room by a projector, while the audio signal is produced by an electronic sound reproduction system.

The cinema control system generally controls the operations related to the projection, including the storage of received programs, the decompression and expansion of the program signals, and the display of the program material. Although the cinema network receives the program only once, the program stored in the storage units can be replayed multiple times. The cinema control system may determine the playback period and/or the number of playbacks allowed for each program. In some cases, the control of the presentation process may be implemented by the electronic projection equipment or a remote control unit, or it is also possible for the presentation to be controlled by a central station or other central unit. The cinema control system may also be designed to combine the projection operations with other cinema operations, such as promotions, ticketing, advertising, signage, environmental control, lighting, loudspeaker operation, etc.

- 14 Each cinema network may consist of several multiplex cinemas, which may be equipped with shared storage and control functions to provide flexible and economical screening options.

The use of digital encryption technology makes it possible to make the digital cinema system inherently secure. The data transmission is made secret from start to finish using various encryption methods. This means that the signal carrying the image and/or sound information is encrypted at the source generation system (SGS) and the encryption is only decrypted during playback in the specific projection room of the cinema system. In addition to electronic security measures, the program material is also protected by physical security measures.

Physical security measures are particularly important in protecting the decompressed and decrypted signals from being downloaded over the wire prior to presentation by the projection equipment of the movie theater system. In a preferred embodiment, the decryption and decompression are performed in a self-contained, securely locked enclosure attached to the projection equipment, which cannot be removed by an unauthorized person, and which physically prevents the retrieval of the decrypted signals. In addition, in the event of intrusion into the locked enclosure, a process is initiated that erases information about the encryption key and/or digital data entering the projector input, or

- Changing 15 prevents copying.

The present invention therefore provides a complete digital movie theater system for compressing, encrypting, and delivering, storing, and playing high-quality program materials from one or more central stations to one or more screening rooms in complex movie theaters or other presentation venues, as well as providing command, control, and monitoring functions.

The features, objects and advantages of the present invention will be more fully described in the following detailed description, with reference to the accompanying drawings, in which like reference numerals indicate like elements throughout. In the drawings,

Figure 1 is a block diagram of a traditional film distribution system;

Figure 2 is a block diagram of an exemplary embodiment of a digital movie theater system according to the present invention;

Figure 3. Block diagram of a film-based source generation system;

Figure 4 is a block diagram of a compression-encryption system; the

Figure 5. block diagram of a modulation-transmission system;

Figure 6. Block diagram of a network control system;

Figure 7. Block diagram of a movie theater system;

Figure 8 is a block diagram illustrating the internal network and redundancies of a central station;

Figure 9 is a block diagram of a movie theater receiver-demodulator unit; the

Figure 10 is a block diagram of a movie theater control system; and

Figure 11. Block diagram of a movie theater decoding system.

The subject of the invention is so-called digital cinema, i.e. a system and method for the electronic distribution of very high quality audiovisual programs, such as films, from one or more central distribution points (central station, central equipment or switchboard) to several receiving stations (movie theater network, movie theater, multiplex movie theaters or presentation systems). Within the framework of the digital cinema system, we improve the compression of image and sound signals, the projection technique, the encryption methods and many other partial solutions. We provide a complete system that may include units for encoding, encrypting, transmitting, storing, decompressing, and extracting audiovisual materials, as well as units for controlling various functions of the system.

Digital cinema aims to replace the current film distribution system, in which films are physically delivered to individual viewing and screening locations, such as movie theaters and screening rooms. Digital cinema eliminates the need to copy films or send them by courier. It also enables the provision of extremely high-quality audiovisual materials and offers “built-in security”

- 17 measures. By transmitting signals carrying audio and video information via satellite or other high-speed electronic transmission media, digital cinema also enables the transmission of live programmes, such as sporting events and concerts, in cinema quality. There is also a way to transmit the programmes to cinemas and store them there on storage media, such as magnetic discs, for later playback.

Figure 2 shows an exemplary embodiment of a digital cinema system according to the present invention. The illustrated digital cinema system 100 consists of two main systems, namely at least one central station 102 and at least one presentation system (movie theater system) 104A...104N. In a preferred embodiment, the central station 102 broadcasts or transmits a signal carrying image and audio information to the movie theater system 104 via at least one satellite 106. The central station 102 serves all movie theater systems 104A...104N that are directly within its range or that are connected to a selected wireless, wired or other high-speed communication system. Typically, several movie theaters or presentation locations (outdoor stage, school, specialty restaurant, etc.) form a network receiving image and audio information provided by the system according to the present invention.

Although a single central station 102 is shown to process the data, it may be desirable to employ a backup central station to enhance network or distribution reliability. In addition, multiple central stations 102 may be associated with the same satellite 106 or other satellites or other connectivity to serve movie theater systems or other venues in a given geographic area (satellite region) 104. This may occur, for example, when competing movie distributors or other service providers in a given service area use different central stations to distribute different levels of programming, to serve different types of equipment, or for other reasons. The present invention generally contemplates the use of multiple satellites and multiple central stations to provide the different levels of service required in a given area.

Within a network of exhibition venues, a movie theater system 104A...104N typically receives the image and audio information. This movie theater system includes, in addition to the units used at all exhibition venues, certain central units. The satellite 106 may be, for example, a geostationary satellite belonging to the Ku band, but other frequencies and satellite orbits may also be used. Various satellite systems and satellite transponders are known, which, taking into account the desired coverage area, costs, desired average capacity, etc., may be suitable for use in the system according to the invention.

At the central station 102, a source generation system 108 provides the system with digital electronic

- 19 audio and video programs. The source production system 108 typically receives film material and uses it to produce magnetic tape carrying digital information or data. The film is digitally scanned at very high resolution and a digitized version of the film or other program is created. The image information is generally produced using the known "telecine" process, while the audio part of the program is created by known digital audio conversion signal processing. The images to be processed are not necessarily obtained from film, they may be individual images or still images or image sequences, including image sequences presented as moving images of variable length. These images may be presented as a series of images or so-called image programs. In addition, other materials may be presented, such as special signs produced for visually impaired viewers, subtitles for foreign-language viewers and/or viewers with hearing impairments, or multimedia materials. Similarly, one or more sound or audio recordings may be used to create the desired audio programs.

Optionally, a high-resolution digital camera or other known digital imaging device or method may also provide the digitized image information. The use of a digital camera that directly generates digital image information is particularly useful for recording live events, as it allows for immediate distribution substantially simultaneously with the event. Computer workstations or similar equipment may also be used.

- 20 can be used to directly produce graphic images for distribution.

The digital image information or program is fed to a compression and encryption system 110 which compresses the digital signal according to a selected known format or method, thereby reducing the amount of digital information required to reproduce the original image in very good quality. In a preferred embodiment, the image source is compressed using the ABSDCT technique. The ABSDCT compression technique is described in the aforementioned U.S. Patents 5,021,891, 5,107,345 and 5,452,104. The audio information is also compressed using standard methods and optionally synchronized with the compressed image information. The compressed image and audio information is then encrypted and/or scrambled using one or more electronic security techniques.

The status of the compression-encryption system 110 is monitored by a network control system 112 and instructs the compression-encryption system 110 to multiplex the compressed, encrypted data with the theater information, security information, and transmission control information as required. The multiplexed signal then enters a modulation-transmission system 114 which modulates, under the control of the network control system 112, and transmits the signal carrying the compressed information to the theater systems, such as the theater system 104A, via satellite 106. That is, the compressed information is wirelessly transmitted

- It is broadcast to movie theaters and screening locations via 21 communication links.

In some embodiments, the compressed image and audio information are transmitted independently and separately. That is, the audio program associated with the image information or program is compressed and transmitted by the same device, but separated in time. In the case of the solution according to the invention, it is not required that the audio information and the images be transmitted simultaneously. If necessary, the associated audio and image programs are associated with each other using a predetermined identification or identification mechanism or scheme. This allows one or more selected audio programs to be associated with at least one selected image program upon playback or presentation, as required. That is, the compressed audio program that was not originally synchronized with the compressed image information is associated and synchronized with the image program upon presentation. As will be discussed later, the compressed image and audio information can be stored together or separately in the central station for transmission at a specified later time.

Although in the case of FIG. 2 the transmitted signal is transmitted via satellite 106, it should be noted that the transmission may also be accomplished using terrestrial wireless systems, such as well-known terrestrial cellular, microwave or other radio frequency transmission means. In order to implement the present invention

- 22 Alternatively, various wired solutions can be used, such as the well-known multi-drop systems, Internet access points, dedicated telephone lines or point-to-point fiber optic networks.

The central station 102 may also include at least one co-located movie theater system 116 for monitoring the quality of signals received from the modulating-transmitting system 114 via satellite 106 and providing measurement data on the reception quality to the network control system 112. The co-located movie theater system 116 does not necessarily have to have all the capabilities of the signal processing systems of similar equipment available in the respective movie theaters; it is sufficient if it only includes a signal receiver with the elements necessary to produce a signal for the purpose of analysis, i.e. to perform the reception, demodulation and decompression of the appropriate quality. For example, the co-located movie theater system 116 obviously does not need to produce the complete high-quality image required for projection in most cases in order to allow the analysis of the signal quality based on certain known characteristics of the transmitted digital data.

If the quality of the transmitted signal is judged to be inadequate, the network management system 112 may make changes to the compression-encryption system 110 and/or the modulation-transmission system 114 to improve the quality of the transmission. For example, if the

- 23 the rate of detected errors in digital data, or individual data frames of the received signal are lost, we change the compression characteristics or transmission parameters, such as signal power, or we can automatically repeat the transmission of individual parts of the signal, or we can completely interrupt the transmission in the event of certain satellite transmission problems.

Although the present invention is equally suitable for presenting visual and audio information in a variety of presentation locations, such as outdoor stages, drive-in movie complexes, community centers, schools, specialty restaurants, etc., for the sake of simplicity, it will be described in the following with reference to an exemplary movie theater or movie theater system. It will be apparent to those skilled in the art how the present invention may be applied to other presentation locations.

The transmitted or relayed signal is received by a receiver-demodulator 120 in the movie theater systems 104A...104N. In the case where the signal is transmitted via a satellite transponder, the receiver-demodulator 120 is associated with at least one receiving antenna 138. The receiver-demodulator 120 demodulates the received signal and performs error checking on the demodulated signal. To assist in this process, checksum information may be added to the compressed information prior to transmission to enable errors in the transmitted information blocks to be detected.

If the error rate is greater than a predetermined value, the movie theater control system 122 may request the signal

- 24 retransmission of the portions containing errors. The request for retransmission may be transmitted by the theater control system 122 to the central station 102 via a return link 113. The return link 113 may be established, for example, via a dial-up or dedicated telephone network, a satellite channel, a packet data link, the Internet, a wireless link, or other low-data-rate communication option.

In some embodiments, the transmission of retransmitted signal portions or data frames to be delivered to the presentation location or movie theater is also performed using the return link 113. The return link 113 is thus configured as a bidirectional data transmission link that transmits, for example, retransmission requests or other information from a movie theater to the central station, or commands, general operational information, or compressed image and audio information from the central station to the movie theater. This bidirectional connection, as will be discussed later, can also be used to transmit data relating to encryption keys.

Movie theater systems 104A...104N consist of at least one, but usually several, theaters 128A...128M. For example, in certain shopping malls, movie theaters are designed as complexes consisting of a series of theaters arranged in one location. These are usually called multiplex movie theaters.

The received signals can be broadcast or transmitted to multiple rooms within a given movie theater complex.

The receiver-demodulator 120 supplies the demodulated signal to a central storage system 123 consisting of storage units 124A...124N for storage via a TIN (Theater Interface Network) 126. The size of the storage units 124A...124N can be varied to accommodate the varying number of screening rooms in a movie theater complex. In cases where presentation is desired simultaneously with the reception of information from the central station 102 (for example, when presenting certain events live), the demodulated signal is transmitted via the TIN 126 to one of the screening rooms 128A...128M.

When a program is presented, information representing the program is retrieved from the storage units 124A...124N and delivered to the designated one or more theaters 128A...128M via the TIN network 126. If the designated theater is theater 128A, decoder 130A decrypts the transmitted signal using information about a secret key provided only to authorized theaters and decompresses it using a decompression algorithm. The decompression algorithm is the inverse of the compression algorithm used in source generation system (SGS) 108. Decoder 130A converts the decompressed image information to a standard (analog or digital) video format used by the projection system and

- 26 electronic projection devices 132A are displayed. The audio information is also decompressed and then transmitted to the sound reproduction system 134A of the given room for playback together with the picture program. When the period required for the authorized presentation of the given program ends, the digitized program information is erased from the designated members of the storage units 124A...124N to prevent unauthorized use of the material. Although not specifically indicated, each of the rooms 128B...128M is equipped with a decoder, a projection device and a sound reproduction device.

If the program is to be presented in multiple locations, the central storage system 123 is configured so that the compressed information representing the program can reach the individual theaters with specific programmable time differences (delays). If the program is to be presented essentially simultaneously in the selected multiple theaters, the programmable time differences are essentially zero or very small. In other cases, depending on the type of storage system and its capacity, the time differences can be set arbitrarily from a few minutes to several hours, so that the timing of the presentations can be changed as flexibly as possible. In this way, movie theater complexes can better adapt to the needs of the market when presenting various events, for example, in the case of the screening of new films.

In the case of live events presented in real time, the procedure is similar to that for film presentations, but the

- 27 t. · .v* · » ' ’^·

Storage in and retrieval from storage units 124Α...124Ν, or only short-term buffer storage, is performed to eliminate any temporary signal transmission disturbances or synchronization problems.

The movie theater system 104 may optionally include one or more digital tape recorders 136. The tape recorders 136 may be used, for example, when satellite connections or other means of transmission are not available, or when the use of these technologies is not practical due to cost or other reasons. In this case, the program may be distributed from the central distribution point to the movie theaters 104 using magnetic tape or other transportable information carrier. The tape recorders 136 deliver the program to the storage units 124A...124N via the TIN network 126. The information representing the program is then available for later playback at any time. The image and audio programs may be copied from the disk storage units 124A...124N to the tape recorders 136 for long-term archiving or for later reloading into the storage units 124A...124N.

Other higher density and higher performance data storage devices may be used instead of the digital tape recorder 136. For example, optical disk, CD ROM type storage devices or multi-purpose digital disk (DVD) devices or even solid state based memory units may be used within the scope of the present invention.

- 28 . Figures 3-9 show the signal processing units of the central station 102. These are described below. Figure 3 illustrates the source generation system 108. In an exemplary embodiment, the source generation system 108 digitizes a film image source, such as 35 mm motion picture film, and stores the digitized version on magnetic tape. The source production system 108 includes a high definition (HD) telecine (television projector) 140 receiving a film source 142 and producing digitized images from the film. Telecine signal processing is well known in the motion picture industry. Any of the techniques and devices available on the market may be used to perform this digitization process. However, it is preferred to use high definition telecine signal processing equipment from CINTEL or Philips BTS. The resolution and other characteristics of the equipment used are determined by cost and other factors to be considered in the selection of services. The choice of resolution used also depends on the intended audience, the available projection equipment, and the target area, for example, on the basis that it is desirable to reduce the data transfer rate for certain satellite transmissions.

If the original film is a standard 35 mm format image source, the image processing is done using a telecine process at 24 frames per second. The digitized output signal obtained by the telecine process is used on a high-data-rate magnetic tape recorder.

- 29 can be stored using a tape recorder or directly compressed and/or encrypted and then stored using a lower data rate tape recorder or other known image storage system or medium.

Since the telecine process only processes the image, the audio portion of the input signal source is processed independently of the image. The analog audio source is typically provided on a magnetic tape 144. The audio signals are digitized by an audio readout unit 146. In a preferred embodiment, up to twelve digitized audio channels can be combined with the digitized image using a multiplexer 148, and the multiplexed signal and the image program are stored using a high-definition digital video recorder (VTR) 150 or other high-capacity digital storage device. Alternatively, as mentioned above, the audio program can be stored and processed independently of the image program, but in this case synchronization information must be added so that the projection room playback system can properly synchronize the audio program with the image program.

Although the source generation system 108 is shown as part of the central station 102, it should be noted that this system may be arranged elsewhere. Other equipment may be suitable for generating the digitized signal from the magnetic or optical source. Alternatively, the source generation system 108 may be a digital signal processor with an embedded magnetic or optical storage device.

- 30 may be a camera or other digital image production device (e.g., a computer system for producing graphics or other effects) that directly produces digital source materials. Source production system 108 may be a still image digitizing system (e.g., an optical scanner) or an image converter that digitizes 35 mm photographic slides or photographs. Accordingly, conventional or, for example, specialized special effects studios, or other systems involved in the production and presentation of image programs may also produce the desired digitized material, which is then sent to central station 102 for further processing or delivery.

Figure 4 shows an exemplary block diagram of the compression-encryption system 110. The compression-encryption system 110, like the source generation system 108, may be part of the central station 102, or may be located in a separate device. The compression-encryption system 110 may be located together with the source generation system 108, for example, in a studio producing film or television productions. In addition, the compression of image or audio information or data may be performed as a variable data rate process.

The compression-encryption system 110 receives a digital signal, for example, provided by the digital video recorder 150 of the source production system 108. The digital image and audio information may be stored in frame buffers (not shown) prior to further processing.

- 31 The digital image signal is fed to an image compressor 162. In a preferred embodiment, the image compressor 162 processes the digital image signal using the ABSDCT technique known from the aforementioned U.S. Patents Nos. 5,021,891, 5,107,345 and 5,452,104.

In the case of the ABSDCT process, the color input signal is usually in the YIQ format, where Y is the luminance component and I and Q are the chrominance and color components, respectively. Other formats, such as YUV or RGB, are also possible. Since the eye has a low spatial sensitivity to color, the ABSDCT process reduces the sampling density of the I and Q color components by a factor of two in both the horizontal and vertical directions. Accordingly, four luminance components and two color components are used to represent each spatial segment of the image input.

The intensity and color components are fed to a block classifier. Typically, blocks of 16x16 are fed to the block classifier, which arranges the image samples within the 16x16 blocks to create data blocks and composite sub-data blocks suitable for discrete cosine transform (DCT) analysis. The DCT operator is a method for converting a time-sampled signal into a frequency representation of the same signal. DCT methods allow for very high compression by converting to a frequency representation, as they can create quantization units that can be used to exploit the

- Advantages of the frequency distribution characteristics of 32. In a preferred embodiment, a first arrangement uses one 16x16 DCT, a second arrangement uses four 8x8 DCTs, a third arrangement uses sixteen 4x4 DCTs, and a fourth arrangement uses 64 2x2 DCTs.

The DCT operation reduces the spatial redundancy inherent in the source image material. After performing the DCT, most of the energy of the image signal is concentrated in a few DC coefficients.

By analyzing the transformed coefficients of a 16x16 block and its subblocks, we determine the number of bits required to encode a given block or subblock. Then, we select the block or combination of subblocks that requires the fewest bits to encode to represent the image segment. For example, two 8x8 subblocks, six 4x4 subblocks, and eight 2x2 subblocks can be selected to represent the image segment.

The selected block or combination of selected subblocks is then arranged in a suitable manner. The DCT coefficient values may be subjected to further processing operations, such as frequency weighting, quantization, coding (e.g. variable length coding), in preparation for transmission using known methods. The compressed image signal is then fed to at least one image encoder 166.

The digital audio signal is usually compressed into 164 audio bits.

- 33. In a preferred embodiment, the audio compressor 164 processes the multi-channel audio information using a standard digital audio compression algorithm. The compressed audio signal is fed to at least one audio encoder 168. The audio information may optionally be transmitted or used in an uncompressed, but still digital, format.

The video encoder 166 and the audio encoder 168 encrypt the compressed video and audio signals, respectively, using one of a number of known encryption techniques. The video and audio signals may be encrypted using the same technique or different techniques. In a preferred embodiment, the same real-time digital sequence scrambling encryption technique is used for both the video program and the audio program.

The video encoder 166 and the audio encoder 168 process the program material using scrambling and encryption circuits that use electronic key information that varies over time (typically several times per second). The scrambled program information can then be transmitted over a wireless link in such a way that it remains indecipherable to those who do not have access to the electronic key information used to scramble the program or digital data.

Encryption is usually achieved by scrambling or compressing a digital signal using a sequence of digital signals.

- 34 is implemented by direct encryption. The terms “encryption” and “obfuscation” are used interchangeably, and these operations are understood to mean any means capable of confusing, masking or directly encrypting digital data streams from various sources using any encryption technique using secret digital values (“keys”), in such a way that it is very difficult to recover the original data sequence without knowing the secret keys.

Each video and audio program uses unique electronic key information that is provided only to those movie theaters or screening locations that are authorized to show the program, disguised by special electronic encryption information depending on the location or theater. Without the encrypted program key, the projection room cannot decrypt the data stream representing the program. The encrypted program key is transmitted by transmission or otherwise to authorized movie theaters prior to the program being played. It should be noted that the data stream for the program may be transmitted several days or weeks prior to the beginning of the authorized playing period, but the encrypted program key is transmitted only immediately prior to the beginning of that period. The encrypted program key is transmitted via a low-speed connection or on a portable storage device such as a magnetic or optical disk, smart—

- 35 may also be transmitted using a card or other device with an erasable memory element. The encrypted program key may be provided in such a way as to verify the period during which a given cinema complex or screening room is authorized to show the given program.

Each screening room that has access to the encrypted program key decrypts this value using its own unique key and then stores the decrypted program key in a memory device or other secured memory.

When the program is played, both the theater or screening room's unique key and the program key are used, preferably with a symmetric algorithm that was used in the encryption system 110 to generate the encrypted signal and that is now used to decrypt the program information in real time.

In addition to performing the scrambling, the image cipher 166 can also add a so-called "watermark" - usually in digital format - to the image program. This means that a location-specific and/or time-specific visual identifier is inserted into the signal sequence carrying the program. The watermark serves to indicate that the presentation of the program is permitted at a given location and time. The watermark can be used to more effectively detect where unauthorized copying has occurred, if necessary. The watermark can be programmed in such a way that it is displayed at frequent, but pseudo-random, timed periods.

- 36 appear during playback and are not visible to the viewing audience. When presenting uncompressed image or audio information at a transmission previously determined to be at normal speed, the watermark cannot be detected. However, if the image or audio information is presented at a speed significantly different from normal, for example at a "non-real-time" speed or in the form of still images, the watermark can be detected. If an unauthorized copy of the program is used, the competent authority can read the information carrying the digital watermark and determine at which movie theater this copy was made. This watermarking method is also suitable for identifying audio programs.

The compressed and encrypted video and audio signals are fed to a multiplexer 170. The multiplexer 170 multiplexes the video and audio signals, as well as synchronization information, so that the video and audio streams can be played in a properly timed manner at the movie theater system 104. The multiplexed signal is then fed to a program packet generation unit 172, which generates the signal stream carrying the program by organizing the data into packets. By organizing the data into packets, or "data blocks," it is possible for the movie theater system 104 receiving the program to perform error checking of the received blocks and, instead of retransmitting the entire program, only request retransmission of the faulty data blocks. This greatly increases the reliability and efficiency of the transmission.

- It increases by 37.

In an alternative embodiment of the present invention, the video and audio portions of the programs are treated as separate programs. In this case, the multiplexer 170 for multiplexing the video and audio signals is omitted, and the video signals are arranged separately into packets for transmission. In this embodiment, the video signal can be transmitted to the exclusion of the audio signal, and vice versa. The video and audio programs are combined into a combined program only at playback. This makes it possible to associate different audio programs with the video programs for various purposes (e.g., to allow for different language versions, post-release updates or program changes, to adapt to local regulations, etc.). This flexibility in producing programs that differ from each other in terms of the audio portion is very advantageous in terms of the cost implications of changes to already in-market programs and the expansion of the multicultural markets available to the film industry.

The compressors 162, 164, the ciphers 166, 168, and the program package generation unit 172 may be implemented in the form of a software-controlled processor programmed in a manner suitable for performing the functions described. These units may therefore be designed as general-purpose hardware comprising various programmable electronic devices or computers controlled by a software or fixed program. Optionally, other technologies (such as ASIC circuits or other printed,

- 38 or integrated circuits). In essence, they are designed as special hardware.

The ^video and audio program stream is fed to a storage system 174. The program stream may also be fed to a digital linear tape recorder 176.

The entire compression-encryption system 116 is primarily controlled and monitored by a CES controller 178. The CES controller 178 can be implemented, for example, by appropriate programming of a general-purpose hardware device or by the use of appropriate specialized hardware. The network control of the CES controller 178 is provided by the network management system 112 (FIG. 2) via a central station internal network to be described later. The CES controller 178 communicates with the compression units 162, 164, encryption units 166, 168, multiplexer 170 and packetizer 172 via a known digital interface and controls the operation of said units. The CES controller 178 controls and monitors the storage system 174 and the digital linear tape recorder 176, as well as the data traffic between these units and the modulation-transmission system 114 (FIG. 2).

The storage system 174 is preferably comprised of hard disk drives and may be generally similar to the disk storage system 124 used in the movie theater systems 104 (FIG. 2). It will be apparent to those skilled in the art that other media, such as rewritable optical discs, may be used in some applications. The capacity of the disk storage system 174 of the central station

- 39 may be less than the resultant of those used in the 104 movie theater systems (i.e., the resultant capacity of all the screening rooms or exhibition spaces) because the storage system 174 generally needs to store only one program at a time. Generally, a new program needs to be stored after all programs have been transmitted and erased from memory. However, multiple programs can be stored simultaneously, and multiple programs can even be transmitted simultaneously over a given connection if the equipment receiving the transmitted material allows this. The disk storage system 174 receives compressed and encrypted picture, audio, and control data during the compression phase from the program packetizer 172 or the digital linear tape recorder 176. During the transmission phase, the disk storage system 174 transmits the stored data to the modulator-transmitter unit 114. The operation of the disk storage system 174 is controlled by the CES controller 178.

The program data stream from the disk storage system 174 and the control information from the CES controller 178 are received by a control multiplexer 180. The control multiplexer 180 multiplexes the two data streams and transmits the multiplexed data stream to a transmission packetizer 182. The transmission packetizer 182 packetizes the data stream to produce a transmission data stream and transmits the packetized data stream to the modulation-transmission system 114.

The digital 176 tape recorder (DTR) archives the compressed image and audio program, and also allows

- 40 the delivery of tape-recorded programs to movie theaters that cannot access them via satellite or other wireless or wired connections. In such cases, digital information is distributed using magnetic tape. The tape recorder 176 receives compressed and encrypted picture, audio and control data from the program packetizer 172 during the compression phase. The archived program can be retrieved, for example, by transferring the data recorded on the tape from the tape recorder 176 to the disk storage system 174. The operation of the digital linear tape recorder 176 is controlled by the CES controller 178.

The modulator-transmitter system 114 shown in Figure 5 modulates and transmits the transmission data stream from the compression-encryption system 110. The modulator-transmitter system 114 includes at least one modulator 200 and an IF upconverter 202, which are generally located in the same equipment as the compression-encryption system 110, the network control system 112 and the co-located movie theater system 116 (Figure 2). The modulator-transmitter system 114 also includes an RF converter 204, a high-power amplifier 206 and a modulator-transmitter system controller 208. These are located in or near an earth station 210.

Modulator 200 is a standard subsystem that uses known methods to add forward error correction information and to provide satellite or other

- Modulates the transmission data stream for transmission over a wireless transmission line 41. In a preferred embodiment, forward error correction is performed using convolutional and concatenated Reed-Solomon coding techniques. Standard PSK (phase shift keying) modulation is used for modulation.

The output signal of the modulator 200 is converted to an intermediate frequency (IF) by an IF upconverter 202, for example, 140 MHz. The signal is then fed to an RF upconverter 204. This subsystem can be implemented using existing equipment, with only minor modifications required to ensure compatibility with other parts of the system in known manner.

The RF upconverter 204 is generally a standard subsystem that converts the IF signal to a transmission signal suitable for satellite transmission. In a preferred embodiment, an IF signal with a frequency of 140 MHz is converted to a Ku-band signal. The Ku-band output signal can be tuned between about 14.0 GHz and 14.5 GHz. In order to increase the reliability of the system, it is convenient to use two upconverters and an automatic switching unit (not shown). The output signal is fed to a high-power amplifier 206 for amplification. Frequency bands other than Ku-band may be used for transmission of signals via satellite.

The high-power amplifier 206 amplifies the Ku-band (or other band) transmission signal for transmission to a satellite transponder. The system

2»

- In order to increase the reliability of 42, it is advisable to use two high-power amplifiers and an automatic switching unit (not shown).

An MTS controller 208 may be used to interface, configure, and monitor the equipment of the ground station 210. The MTS controller 208 may be implemented using well-known programmable hardware, such as a personal computer or workstation.

The ground station 210 is comprised of RF links and an antenna. Typically, an RF unit including an RF upconverter 204, a high-power amplifier 206, an MTS controller 208, and optionally a power supply (not shown) and air conditioning equipment is utilized. The ground station 210 typically transmits program information and control information to the movie theater systems using one or more common broadcast channels. The transmitted signal includes control information that allows the movie theater systems to identify each program being transmitted. Control information is also transmitted to the movie theater systems to cause each movie theater to selectively record only those programs received that are broadcast to that movie theater system. Information is also transmitted for other control functions related to system operation. As we have already mentioned,

- 43 this information can be transmitted via both high-speed and low-speed connections as required.

The network control system 112 shown in Figure 6 controls and manages the digital cinema system 100. This includes controlling and monitoring the central station units 102 and the network of the movie theater system 104. Control may be centralized, with the network control system 112 controlling the operation of the entire system, including control of the broadcast or transmission, playback-presentation, security measures, and general network management functions. Alternatively, a distributed control system may be used, with processors in the presentation or movie theater systems controlling some of the functions of the movie theaters.

The network control system 112 includes at least one network control processor 220. This constitutes the central control unit or "brain" of the digital cinema system 100. The network control system 112 is generally based on a standard workstation or similar programmable data processing hardware. The network control processor 220 determines the timing and security regime of the digital cinema system 100.

The various programs may be pre-broadcast from the central station 102 to the movie theater systems 104 for later presentation in an order determined by the network control system 112. This procedure is generally used unless the event is occurring in real time.

- 44. In this way, the control of the playback of the pre-recorded program, which is delayed in time relative to the time of its broadcast from the central station 102, takes place in a separate process.

The network control processor 220 also determines the rate at which programs are broadcast, transmitted, or forwarded. The rate may be fixed or may vary depending on the nature of the program and the design of the transmission signal. For example, the rate may depend on the transmission rates of a particular satellite transponder or other data transmission link. For higher data rates, programs may be transmitted in parallel. For programs that are stored for playback at a later time, the data rate may be greater than, less than, or equal to the real-time rate of the given program. The data rate of the compression encoding of the program material may also vary for each program, allowing for the use of compression methods corresponding to different quality levels. In the case of live events, data transmission at a rate corresponding to the compression rate is used.

A second network controller processor can be used as a backup. The network controller processor 220 connects additional units to the system via the central station's internal network. This internal network is typically a standard, multi-port network.

- 45 can be implemented using a network, such as an Ethernet network. Optionally, other known networks, such as optical networks, can also be used. In the present case, the Ethernet unit 224 of the network management system 112 supports the internal network of the central station, as shown in

We will discuss Figure 8 later.

The network control system 112 also includes a modem unit 226 which provides connectivity to the network of movie theaters via the PSTN (public switched telephone network) and which typically consists of a series of dial-up telephone modems, cable or satellite modems, ISDN or cellular connection controllers, or other known devices. The modem unit 226 provides connectivity to the network control processor 220 via a modem server function. The modem unit 226 provides a receiver for the signal associated with the return link between the movie theaters and the central station 102. This signal path is used by the movie theaters to forward requests for retransmission of program data blocks received in error from the central station 102. The same signal path can be used to request the retransmission of certain programs or changes or updates to program material. The transmission of requests for retransmission and the retransmission itself may occur both during and after the transmission of the program material. In alternative embodiments, the return link signal path may be a satellite channel or other low-data-rate communication option or the Internet.

- 46. In this case, instead of the modem unit 226, other suitable known devices are used to establish the connection.

The co-located movie theater system 116 shown in Figure 7 monitors the quality of the transmitted signal and sends quality measurement data to the network management system 112.

The co-located movie theater system 116 includes at least one movie theater receiver 232, which is generally configured to be similar to the movie theater system 104. The receiver 232 receives signals transmitted by the modulating-transmitting system 114 via the satellite 106 using at least one receiving antenna (parabolic antenna) 234. Alternatively, a cable or fiber optic connection may be used if the quality of the connection is controlled using other signal paths. The co-located movie theater system 116 also includes at least one control processor 236 that receives the signal from the movie theater receiver 232 and measures the quality parameters of the transmitted signal. The control processor 236 also reports the quality to the network control system 112. In a preferred embodiment, the control processor 236 is connected to the network control system 112 via an Ethernet network or high-speed data bus.

Figure 8 shows an exemplary block diagram of the central station internal network 250. The network 250 forms the backbone of the central station 102. The central station internal network 250

- 47 network can be configured as an Ethernet LAN network according to the IP protocol. The internal network 250 of the central station establishes a physical connection within the central station between the compression-encryption system 110 (110A, HOB), the modulation-transmission system 114 (114A, 114B), the network control processor 220 and the co-located movie theater system 116 (116A, 116B). In order to conveniently share local and remote functions, an external interface can also be used towards the central station 102 and an external computer network or communication system.

In a preferred embodiment, the central station 102 also provides backup or redundancy elements in the event of a primary unit failure. Each system in the central station 102 has a primary system and either a parallel-connected backup system or a built-in backup system with automatic switchover (see FIG. 8). The central station's internal network 250 is thus connected to the compression-encryption systems 110A, 110B, the network control processors 220A, 220B, and the co-located movie theater systems 116A, 116B through a series of backup (backup) Ethernet transceivers 254A...254E.

254A...254E Ethernet transceivers communicate via two or more Ethernet cards (here Ethernet cards 252A and 252B). A person skilled in the art can create such redundant systems and connections without any further ado, and is aware that

- 48 how to increase the safety in the event of failures by adding additional systems, appropriate connections and interface elements if necessary. By using redundant signal processing systems, our goal is to ensure the most reliable operation in extremely time-sensitive and demanding markets, such as movie theaters. Some spare units can work in “standby” or “warm start” mode, so that they can immediately enter the system with a simple switchover if necessary.

As mentioned above, the central station 102 distributes audiovisual programs to presentation locations or movie theater systems, such as movie theater system 104. Figures 9-11 illustrate exemplary embodiments of signal processing units of movie theater system 104.

Figure 9 shows the receiver demodulator unit 120 of the movie theater system 104. The receiver demodulator unit 120 includes an outdoor unit 270 having a low noise unit and a satellite dish directed to and following the satellite 106. The outdoor unit 270 receives the signal transmitted by the central station 102, amplifies it and converts it to an intermediate frequency (IF) for further processing. The satellite dish is usually a feed-forward satellite dish. The diameter of the antenna used is between 1.0 and 1.6 meters, depending on the geographical location of the receiver and the frequencies to be received. The satellite dish is either roof-mounted or roof-mounted.

- 49 may be mounted on a mast. The dimensions of the parabolic antenna are generally selected so as not to exceed the values permitted by various state and local regulations. The low noise unit is generally a standard digital video broadcasting low noise unit (DVB LNB) that amplifies the received signal and downconverts it to an IF frequency for the processing demodulator. In a preferred embodiment, the LNB unit provides an L-band IF output signal. The LNB unit has a receiving funnel arranged at the focal point of the parabolic antenna. The LNB unit is connected to the demodulator 272 of the receiver-demodulator unit 120 via a standard coaxial cable.

The receiver-demodulator unit 120 includes, in addition to the demodulator 272, an automatic repeat request processor 274 and a forward demultiplexer 276. In a preferred embodiment, these three units are configured as a circuit board that can be easily plugged into a general purpose computer (e.g., an IBM-compatible personal computer) or workstation. This circuit board can be located in the movie theater control system 122.

As mentioned above, although the central station 102 broadcasts multiple programs and the movie theater system 104 is capable of receiving all of the broadcast programs, the latter selectively demodulates and stores only those of the received programs that are intended for it. The broadcast program stream includes multiplexed control information that informs each movie theater system which programs to play.

- 50 are authorized to demodulate and store.

The demodulator 272 thus extracts the data and clock of the selected program from the IF signals received by the outdoor unit 270. The demodulator 270 may employ various known demodulation techniques. For example, if the program signal is modulated using the QPSK technique, the QPSK demodulation technique is employed. The demodulator 270 may be designed, for example, to conform to standard integrated circuits used in receivers used for receiving direct broadcast video programs. These demodulator devices generally also provide forward error correction (FEC) signal processing functions. Error correction may be accomplished, for example, by convolutional encoding and decoding in conjunction with concatenated Reed-Solomon encoding and decoding and Viterbi decoding. In a preferred embodiment, the convolutional code has k=7, r=7/8, and the Reed-Solomon code has a value of (204,188). The output signal subjected to error correction is sent to the ARQ processor 274.

The ARQ processor 274 performs additional error correction on the signals received from the demodulator 270. The ARQ processor 274 calculates a digital signature consisting of fixed-length blocks of consecutive data of the demodulated signal, for example, using cyclic redundancy check (CRC) codes. The digital signature calculated for each block is compared to a digital signature calculated by the modulator-transmitter unit 114 of the central station 102 using the same digital signature algorithm and transmitted to the satellite channel.

- 51 with the value transmitted with the data stream. If the digital designation calculated by the ARQ processor 274 does not match the designation transmitted with the data, a block error is indicated. Each data block has a unique block identifier value. The ARQ processor 274 records the block identifier of each data block for which there is a difference between the transmitted and calculated values of the digital designation. The theater control system 122 may request retransmission of any or all of the data blocks for which there is a difference in the digital designation using the return link signal path 284. The network control system 112 of the central station may then retransmit the blocks requested by the theater systems 104. The theater control system 122 may insert retransmitted blocks with matching block identification values in place of blocks for which the locally computed digital designation value did not match the transmitted value. By using these methods, the resulting error rate of the received signals can be greatly reduced. The output data of the ARQ processor 274 preferably has an error rate between 1x10~ ¹⁰ and ^1x10'11 or less. This data is fed to a forwarding demultiplexer 276.

The forwarding demultiplexer 276 demultiplexes the demodulated data stream packets, sends command packets to the movie theater control system 122, and sends compressed encrypted image and audio packets to the 124

- 52 storage systems.

Figure 10 illustrates an exemplary embodiment of a movie theater control system 122. The movie theater control system 122 shown controls and monitors the entire movie theater system 104 or all of the screening rooms of a movie theater complex. The movie theater control system 122 may also employ a program control device or apparatus that can generate individual program sets from received video and audio programs and present them in a specified time sequence within the time interval allowed for it in its screening rooms.

The movie theater control system 122 includes a movie theater control processor 280 and at least one modem 282 or other device connected via a return link 284 to send messages to the central station 102. The movie theater control system 122 also includes a visual display element, such as a monitor, and a user interface device, such as a keyboard, which may be located in the manager's office or ticket office of the movie theater complex or other location suitable for performing movie theater operations.

The movie theater controller processor 280 is generally a standard commercial or industrial grade computer. As shown in Figures 10 and 2, the movie theater controller processor 280 communicates with the storage systems 124A. . . 124N, the decoder units 130, and the digital tape recorder 136 via the movie theater interface network 126. The

- Movie theater controller processor 280 communicates with the central station network via a return link 284. In a preferred embodiment, a modem 282 is used to communicate with the central station 102. Modem 282 is typically a standard telephone line modem that is located in or connected to the processor and communicates with the central station 102 via a standard two-wire telephone line. In alternative embodiments, communication between movie theater controller processor 280 and the central station 102 may be via low-data rate connections, such as the Internet, private or public data networks, or wireless or satellite communication systems. In these alternatives, modem 282 is adapted to provide the necessary interface structure.

The information transmitted via the return link 284 includes requests for retransmission of information received by the movie theater system 104 from the satellite 106 that has been found to contain uncorrectable bit errors, as well as control and monitoring information, operational reports and alarms, and optionally information regarding encryption keys. The messages transmitted via the return link 284 may be protected by means of an IEJ signal for tamper protection and/or for verification and authorization purposes.

- 54 The movie theater controller 280 processor may be designed to be capable of fully automated operation of the presentation system, including control of playback and presentation, implementation of security measures, and performance of network management tasks. ^The movie theater controller 280 processor may also control the performance of peripheral movie theater tasks ( ^e.g. , ticket advance purchase and sale, implementation of various promotions, control of environmental parameters). Alternatively, manual intervention may be used to supplement the control of certain movie theater operations. The movie theater controller 280 processor may also interface with certain existing automatic control systems of the movie theater complex for complex control or adjustment of various functions. Alternatively, certain movie theater operations (e.g., playback and presentation, and implementation of security measures) may also be controlled from the central station 102 via radio waves. The system to be used is of course selected depending on the available technology and the needs of the given movie theater.

The system of the present invention generally supports the simultaneous playback and presentation of recorded programs on multiple projectors, either through control provided by the theater control system 122 or by a network control system. The various programs to be played on one or more projectors of the theater system 104 may be stored in a storage system comprising storage units 124A...124N. As previously mentioned, the theater system 104 may play program material received via a broadcast channel without delay. In this case, the storage capacity of the system is not utilized.

In addition to controlling the theater control system 122 or a network control system, it is also possible to allow a given program to be played multiple times without having to send the program itself to the theater system 104 multiple times. The security measures used can be used to verify that the given program is actually played for the authorized period(s) and with the authorized number of repeats.

It can be seen that the automatic control implemented by the movie theater control system 122 and the central network control system 112 provides a suitable means for automatically distributing, storing and presenting programs under programmable control from the central facilities. In addition, with the use of a suitable control element, certain preselected network operations can be controlled from a location remote from the central facilities. For example, a television or film studio can automate and control the distribution of films and other productions from a central location, such as a studio office, and can make almost instantaneous changes to the program in response to rapid changes in market demand or the response to the material presented or other professional considerations.

- 56 presented materials.

As shown in FIG. 2, the theater interface network 126 provides a physical connection between the theater control system 122, the storage units 124A...124N, the projection rooms 128A...128M, and the digital tape recorder 136. The theater interface network 126 is an electrical or optical LAN network that provides local transmission of programs within the theater system 104. Programs received and demodulated by the receiver-demodulator 120 are transmitted to the storage units 124A...124N via the theater interface network 126 for storage. Programs stored in the storage units 124A...124N or received for real-time playback are transmitted via the theater interface network 126 to one or more projection devices in the theater system 104. The movie theater interface network 126 can be constructed from any standard LAN network architecture that provides adequate data transfer speed and connectivity, and provides sufficient reliability as a network that is interleaved, switched, or directed to the central station.

As also shown in FIG. 2, storage units 124A...124N provide local storage of programs authorized for playback and presentation. In a preferred embodiment, each movie theater system has a central storage system. Storage units 124A...124N allow each movie theater system to provide presentations in one or more screening rooms, and

- 57 programs should be shown simultaneously in several screening rooms.

The storage units 124A...124N, sometimes referred to as disk storage units 124A...124N, may be conventional solid-state, magnetic or optical storage devices well known in the art. In some preferred embodiments, the storage units are magnetic disk drives, commonly known as hard disk drives, as used in the computer industry. These devices are inexpensive and have data transfer rate characteristics that make them suitable for use in the systems of the invention. They are manufactured using well-known technologies, with increasingly larger capacities. However, for some applications, other devices, such as rewritable optical storage devices or even solid-state memory devices, may be advantageous.

The central storage system can store multiple programs simultaneously. The central storage system is connected via a LAN network in such a way that any authorized presentation system (e.g., projector) can play and present any program. It is also possible for the same program to be played simultaneously by two or more presentation systems.

As already mentioned, the compressed information representing a given image program in the brain can be transmitted from the storage units to the individual projection rooms with predetermined time offsets or delays in a programmable manner relative to each other. If these offsets are essentially equal to zero, at the same time

- 58 programs are essentially shown simultaneously in multiple screening rooms. In other cases, these offsets are set to different values to accommodate different presentation schedules.

The 124A...124N disk storage units consist of hard disk drives that store encrypted and compressed programs for scheduled playback in designated theaters. The 124A...124N disk storage units are scalable to efficiently support the storage needs of individual movie theaters. In addition, each 124A...124N disk storage unit has built-in redundant storage to ensure that stored program information is not lost in the event of a storage unit failure. For example, the 124A...124N disk storage units are designed to be expandable, rack-mounted, to facilitate adaptation to the changing storage needs of individual movie theater systems. The use of disk storage units 124A...124N enables the cinema management to dynamically forward the programs to be shown to the various screening rooms of a cinema complex and to appropriately time, for example, the programs before the feature film. This is done in a very flexible manner, which allows for adaptation to rapidly changing needs and market demands.

In a preferred embodiment, each storage unit 124A...124N has a storage capacity such that all of the movie theater systems in the given movie theater system can be

- be able to store the programs of 59 screening rooms. In addition, we provide sufficient storage capacity to store programs to be shown later until the time of the screening authorization, while also storing the programs currently licensed for screening. By having this amount of storage capacity available, we can deliver programs licensed for later screening hours, days or weeks before the licensed playback time to the appropriate location without disrupting the playback and presentation of programs currently licensed for screening at that time. We estimate that in such an arrangement, approximately 120 Gigabytes of digital data storage capacity is required per screening room. This capacity value applies to the case of currently used compression and image processing methods. With the development of technology, it is likely that the storage capacity requirement will be reduced in the near future.

The storage space of the discs is dynamically assigned to the programs loaded into storage units 124A...124N. This concept works well for large movie theaters with multiple screening rooms, since the average of the screening times of short and long programs usually gives a nominal duration of about 2 hours. For single-screen movie theaters, the storage capacity must be sufficient to store the longest programs.

Disk storage units 124A...124N are generally designed to perform simultaneous reading and writing.

- 60 possible. In this way, it is possible, for example, that while several previously stored programs are being presented (multiple simultaneous or near simultaneous, separate read-out operations), a new program is simultaneously downloaded from the 106 satellite (write-in operation). With the use of currently available technology, the capacity of individual elements of the disk storage units 124A...124N is physically limited. Therefore, for each individual element, it is determined how many simultaneous or near simultaneous read-out operations (projections) the given element can support in addition to a simultaneous download process (write-in operation). In the case of using such a system, larger movie theaters need additional disk storage units to support the appropriate number of simultaneous playbacks. According to our estimates, one additional disk storage unit is usually needed for every five screening rooms.

However, storage units can also be designed or configured to operate in a so-called striping mode, when the received information is distributed across the storage unit, i.e. during storage, the received data to be stored is partially directed to different drives. Part of the incoming data is sent to a specific drive, while the next part is sent to the next drive, etc. Each drive is given a certain amount of time (latency) to write the data, and after that time, the given drive is allowed to receive data again. In this way, the received data is divided into smaller parts or segments,

- 61 which are stored by each drive at the highest (or at least high) data rate allowed for them, taking advantage of the input buffer capacity and memory storage available in the input channel of the given drive. This allows devices with lower transfer rates to essentially record data in parallel, and ultimately we can achieve very high transfer rates. This method of storage also provides multiple error protection.

When storing data on drives or other storage devices, parity information is used to allow the program to be reconstructed upon retrieval, that is, to provide a means by which parts of the program can be reassembled at the time of retrieval or presentation.

The disk storage units 124A...124N can be scaled in two ways. The storage area per partition can be changed by adding or removing disk drives within the disk storage units 124A...124N. The scaling unit is determined by the size of the disk drives. Alternatively, additional storage units can be used in the movie theater system 104 to support additional presentations.

In a preferred embodiment, the disk storage units 124A...124N may be based on backup units (RAID) constructed from inexpensive devices that are capable of recovering an entire data file in the event of a storage unit failure. The disk storage units 124A...124N

- 62 storage units also provide status and warning signals to facilitate troubleshooting. This arrangement also allows for remote status signaling, monitoring, and diagnostic functions.

As shown in FIG. 2, the movie theater system 104 generally includes a digital tape recorder (DTR) 136. The DTR 136 is used to load the compressed-encrypted program into the disk storage units 124A...124N when a satellite connection is not available and the program is delivered to the movie theater using magnetic tape. The DTR 136 communicates with the disk storage units 124A...124N via the TIN network 126.

The 136 DTR does not generally have a transfer rate that can support direct transfer of the program to the projection device. Both the read and write operations are performed in a so-called burst mode (in shock-like data waves). Therefore, large buffers must be used to smoothly transmit the data stream directly to the projection device. For these reasons, the 136 DTR is used for archiving and data transfer when a satellite channel is not available. The programs downloaded from the 136 DTR are stored in the disk storage units 124A...124N for full-speed playback corresponding to real-time playback. The 136 DTR is controlled by the movie theater control system 122.

By connecting the 104 movie theater system to 136 DTR

- 63 units are provided, enabling movie theater complexes to implement the digital cinema system and take advantage of its other advantages even in the absence of satellite connections or channels. In such cases, the digitized, encrypted films must be physically delivered to the movie theaters using magnetic tape - in a manner similar to current film distribution methods. The 136 DTR can also be used for long-term archiving of programs previously recorded and stored in the disk storage units 124A...124N. In this case, the program can be transferred from the disk storage units 124A...124N to the 136 DTR unit, and the resulting recorded copy can be preserved for later reloading into the disk storage units 124A...124N. Other known magnetic, optical or solid-state storage devices or technologies with similar functions can also be used instead of the 136 DTR unit.

When a program is to be presented, information representing the program is transmitted from one or more disk storage units 124A...124N to one or more projection rooms 128A...128M of the motion picture theater system 104 via the theater interface network 126. FIG. 11 shows an exemplary block diagram of a system of projection rooms 128A...128M. In the system shown, a decoder 130a processes the compressed-encrypted program to be visually presented on a screen or projection surface and to be audibly played back by a sound reproduction system 134. The system of projection rooms 128A...128M is a motion picture theater system 290

- 64 interface network, at least one packet decompressor 292, a projection room controller 294, an image development and decompression system 296, an audio development and decompression system 298, a projection device 132A and a sound reproduction system 134A. All units except the projection device 132A and the sound reproduction system 134A may be implemented on one or more circuit boards. These circuit boards may be housed in a separate, closed housing mounted on or adjacent to the projection device 132A. In addition, a smart card 300 may be provided for transmitting and storing unit-specific encryption key information in communication with the projection room controller 294 and/or the image development and decompression system 296.

The interface 290 of the movie theater interface network allows all the projection rooms to communicate with the storage units 124A...124N or the movie theater control system 122 via the movie theater interface network 126. The interface 290 of the movie theater interface network includes a buffer memory for the purpose of transferring high-speed information portions (data waves, bursts) from the storage units 124A-124N at a high data rate via the movie theater interface network 126, or for processing at a lower speed by other units of the individual projection rooms 128A...128M of the movie theater system.

The 122 movie theater control system and the 294

- Control and monitoring data is transmitted between the projection room controller 65, while encrypted and compressed programs are transferred via this interface to the image and audio decompression and decompression systems 296, 298. Information sent to the projection room 128A is received by the packet decompressor 292. Information sent to other parts of the movie theater system 104, however, is ignored by the packet decompressor 292.

The decompressor 292 identifies and separates individual control, image, and audio packets arriving from the interface 290 of the movie theater interface network. The control packets are forwarded to the theater controller 294, while the image and audio packets are forwarded to the image and audio decompression and decompression systems 296, 298.

The theater controller 294 configures, operates, and monitors the theater system 128A, and implements security measures. The system includes external interfaces, video and audio decompression and decompression systems 296, 298, and the projector 132A and the audio reproduction system 134A. Control information is received from the theater control system 122, a remote control port, or a local control input, such as a control panel on the exterior of the housing or enclosure of the theater system 128A. The theater controller 294 also manages electronic keys assigned to the theater system 128A.

- Prior to the decompression process 66, the image and audio information is decompressed using predetermined electronic encryption keys assigned to the projection room system 128 and electronic encryption key information embedded in the image and audio data. In a preferred embodiment, the projection room controller 294 utilizes projection room system software embedded in a standard microprocessor as a basic functional or control element.

The theater controller 294 is further preferably configured to communicate specific information to the theater control system 122 during operation to record key performance data for each theater. The recorded performance data is then available for transmission to the central station 102. The transmission may be made at specified intervals, for example, via the return link or by using a transportable carrier medium.

The image decompression/decompression system 296 takes the image data stream from the packet decompression unit 292 and reconstructs the original image for display on the screen. This operation typically results in standard analog RGB signals being transmitted to the digital projector 132A. The decompression and decompression typically occur in real time, allowing for real-time playback of the program material.

- 67 The image decompressor and decompressor system 296 performs the reverse of the processes performed by the image compressor 162 and the image encoder 166 of the central station 102 in decompressing and decompressing the image data stream. Each projection room system 128 may process and present different programs from the other projection room systems 128 of the same movie theater system 104, but it is also possible for two or more projection room systems 128 to process and present the same program simultaneously. In some cases, it is also possible for several projection devices to present the same program with a time offset relative to each other.

During the decompression process, previously provided unit-specific and program-specific electronic encryption key information, as well as electronic keys embedded in the data stream, are used to decompress (decrypt) the image information. The decompression process has been previously described in detail in connection with the description of Figure 4. Each 128 projection room system is provided with all the encryption key information necessary to present all the programs authorized for it.

A multi-level cryptographic key management system is used to authorize each presentation system to present specific programs. This multi-level cryptographic key management system generally provides a set of 128 image and/or audio keys for each authorized projection room system and for each image and/or audio program.

- 68 uses unique electronic key values assigned to audio programs and/or a time-varying cryptographic key sequence within the image and/or audio programs. A so-called screening room-specific electronic key - usually at least 56 bits long - is programmed into each screening room system.

This programming can be done using various techniques for transmitting and providing the key information. For example, the return link established via a satellite or other channel as described above can be used to transmit the cryptographic key information. Optionally, smart cards, pre-programmed so-called flash memory cards and other known portable storage devices can also be used.

For example, a smart card can be designed in such a way that this value, once loaded into the card, cannot be read from the smart card's memory. Physical and electronic security measures are used to prevent this key information from being manipulated and to detect any attempts at manipulation or interference. The key is stored in such a way that it can be erased if a manipulation attempt is detected. The smart card circuit has a central microprocessor containing a software form of an encryption algorithm (usually according to the DES data encryption standard). The smart card is able to encrypt (or decrypt) the input values it receives if these values are in the

- 69 uses the DES algorithm installed on the card and the pre-stored screening room specific key and outputs the result. Alternatively, the smart card is simply used to provide the encrypted electronic key information to the screening room system 128 so that it can process this key information for use in decrypting the image and audio information.

The data streams representing the video program are subjected to dynamic video decompression using an inverse ABSDCT algorithm or other video compression method symmetric to the video compression method used in the compression-decoding system of the central station 110. If the video compression was performed using the ABSDCT algorithm, the decompression process includes variable length decoding, inverse frequency weighting, inverse differential quad-tree transformation, IDCT, and DCT block-combining inverse dequeuing (dequeuing). The signal processing elements used for the decompression may be implemented using dedicated special hardware configured for this purpose, such as an ASIC circuit or one or more circuit cards. Alternatively, the signal processing elements used for the decompression may be implemented as standard elements or general-purpose hardware, including a variety of digital signal processing units controlled by special software or a fixed program, or

- 70 programmable electronic devices or computers. Multiple ASIC circuits that process image information in parallel can also be used to process image information if high image data rates are to be supported.

The decompressed image data is subjected to digital-to-analog conversion, and the resulting analog data is transmitted to the projection device 132A. Alternatively, the decompressed digital image data may be transmitted to the projection device 132A using a digital interface. In this case, no digital-to-analog conversion is required.

The audio information extraction and decompression system 298 takes the audio data stream from the decompressor 292, decrypts it, and restores the original audio program for presentation through the movie theater speakers or audio reproduction system. As a result of this operation, the audio reproduction system 134A receives standard-level audio signals.

The audio information extraction and decompression system 298 reverses the operations performed by the audio compression unit 164 and the audio encryption unit 168 of the central station 102 in a manner similar to the image information extraction and decompression system 296. The decryption system 350 decrypts the data using electronic keys received from the cryptographic smart card 304 and electronic keys embedded in the data stream.

- 71 the audio information. The decrypted audio information is then subjected to decompression.

The audio information is decompressed using a symmetric algorithm compared to that used by the central station 102 for audio information compression. If there are multiple audio channels, all of them are decompressed. The number of audio channels depends on the design of the sound reproduction system of the particular projection room or presentation system. Additional audio channels may be transmitted from the central station 102 to provide higher quality audio programs, such as multilingual audio channels and assistive audio signals for visually impaired viewers. The system may also provide additional data channels synchronized with the video programs, such as for special multimedia effects, subtitles, and special visual cues for hearing impaired viewers.

As already mentioned, the audio and data channels can be synchronized with the image programs, but in some cases they can also be presented asynchronously, without direct synchronization. Image programs can consist of individual images (still images), a series of individual images (still images), or a series of short or long moving images.

If necessary, the audio channels can be fed into an audio delay element that introduces the necessary delay to synchronize the audio signal with the corresponding video signal. Each channel then undergoes digital-to-analog conversion to 134A

- 72 sound reproduction systems receive a suitable, so-called "line level" signal. This means that the digital data is converted into analog level or format signals required to drive the given sound reproduction system. Line level audio output signals are usually connected to standard XLR or AES/EOU connectors found on most movie theater sound reproduction systems.

The projector 132A displays the electronic version of the program on a projection screen. The high-quality projector uses advanced technologies such as liquid crystal light valves (LCLV) to process the optical and image information. The projector 132A receives a video signal, typically in red-green-blue (RGB) format, from the image information decompression and decompression system 296. The information required to control and monitor the projector 132A is transmitted from the projection room controller 294 via a digital serial interface.

As shown in Figure 11, the decoder module 302 includes a fiber optic channel interface 290, a packet decompressor 292, a projection room controller 294, a video information extraction and decompression system 296, an audio information extraction and decompression system 298, and a cryptographic smart card 300. The decoder module 302 forms a self-contained, secure unit that, in addition to the cryptographic smart card interface, includes an internal power supply and/or control, and (if necessary)

- 73 includes a cooling fan, a local control panel and external interfaces. The local control panel may employ any of a variety of known input devices. It may be configured, for example, as a flat panel with a membrane switch and embedded LED displays. The local control panel may be configured, for example, on or as part of a hinged door providing access to the interior of the enclosure for maintenance or repair purposes. This door is provided with a security lock to prevent unauthorized intrusion, theft or tampering with the system. When installed, a cryptographic smart card 300 containing information relating to the cryptographic key (the unique key to the particular screening room) is secured within the decoder module 302 behind the locked front panel. The slot for receiving the cryptographic smart card 300 is accessible only from inside the fixed front panel. The RGB signal output from the image information extraction and decompression system 296 to the projector 132A is securely transmitted within the decoder module 302 in such a way that the RGB signals are not accessible as long as the decoder module 302 is attached to the projector housing. Security connectors can be used to prevent the decoder module from operating if it is not properly attached to the projector.

The audio portion of the program is delivered to the movie theater speakers by the sound reproduction system 134A. In a preferred embodiment, the sound reproduction system 134A

Λ. ’♦.· »7· ·,

- 74 receives up to twelve standard format audio signal channels from the 298 system that extracts and decompresses audio information, in digital or analog format.

The present invention therefore provides a digital cinema system and method for electronically distributing high quality audio and/or visual program materials for presentation in movie theaters or other locations. The system and method of the invention also allows for flexible changes in the presentation schedule of feature films and advertisements, integration of high quality audio and video signals, simple implementation of security measures, and other features and advantages.

Based on the above description of the preferred embodiments, one skilled in the art can make and use the present invention without further ado. Those skilled in the art can modify these embodiments in many ways and can develop additional embodiments without inventive step by applying the general principles presented herein. The present invention is therefore not limited to the embodiments presented herein, but is to be interpreted as broadly as possible in accordance with the principles and novel features described.

Claims (110)

Patent claims 1. Apparatus for delivering digitized image information to display locations, characterized in that it has at least one central station for receiving and compressing digitized image information in a predetermined format; and means for delivering the compressed image information to one or more remote display systems; and means for each display system for receiving the transmitted image information and storing it for display at at least one preselected time; means for distributing the stored compressed image information to one or more decompression systems; means for decompressing the transmitted image information in each decompression system; and at least one projection system for receiving the decompressed image information and presenting visual images represented by the image information in a presentation event. 2. The apparatus according to claim 1, characterized in that it has a means for storing the compressed image information in a distributed manner. 3. Apparatus according to claim 1 or 2, characterized in that it has means for performing the information compression at a location remote from the central station. 4. The apparatus according to any one of claims 1-4, characterized in that it has a digital image generation system for generating images in digital format. ⁵ · ^{The apparatus of claim 4} ·, further comprising a central station for receiving, compressing, and transmitting images from the imaging system to the preselected authorized display systems substantially simultaneously with the digitization of the images, substantially in real time. 6. The apparatus according to any one of claims 1-5, characterized in that it comprises means for storing the compressed image information in the central station for transmission at a later, predetermined time. 7. The apparatus of any one of claims 1 to 6, characterized in that it has at least one central station for receiving and compressing digitized audio information in a predetermined format; and each central station has means for distributing the stored compressed audio information to one or more decompression systems; and means for decompressing the transmitted audio information in each decompression system; and at least one sound reproduction system for receiving the decompressed audio information and presenting it as part of the presentation event. $· Apparatus according to claim ⁷ , characterized in that it has means for compressing the digitized audio information at a variable rate. 9. Apparatus according to claim 7 or 8, characterized in that it has means for compressing and transmitting audio programs associated with image information, separated in time from the associated image, and for applying an identifier enabling one or more preselected audio programs to be linked to at least one preselected image program in a manner suitable for the purpose of presentation. 10. The apparatus according to claim 8 or 9, characterized in that it has a means for providing an audio program consisting of several audio channels to be presented together with the same video program during various presentation events. 11. Apparatus according to any one of claims 1-10, characterized in that it has means for compressing the digitized image information at a variable rate. ¹² · The device according to any one of claims 1-11, characterized in that the display system has a means for encrypting the information and the display system has a means for decrypting the encrypted information. 13. The apparatus of claim 12, further comprising means for providing the authorized presentation systems with encryption key information necessary for decrypting the encrypted information in a manner separate from the transmission of the information. 14. The apparatus of claim 12, characterized in that the information for authorized presentation systems is encrypted information. - 78 has a means of storing and transporting the cryptographic key information necessary for its decryption in a time-separated manner from its transmission. 15. Apparatus according to claim 13 or 14, characterized in that it has means for indicating the validity period of the secret key information and ensuring that the key is used exclusively during this period. 16. The apparatus of claim 15, further comprising means for overwriting the encryption key information in a storage location after the expiration of the validity period. 17. The apparatus according to any one of claims 1-16, characterized in that it comprises means for adding to the image information at least one watermark that is not visible when the decompressed image information is presented at a predetermined normal transmission rate, but becomes visible when presented at a rate significantly different from normal. ¹⁸ · ^{The apparatus according to claim 17} ·, characterized in that it has a means for providing a watermark identifying the time and place of presentation of the image or audio information. 19. The apparatus according to claims 1-18, characterized in that it has a modulating transmission system for establishing a wireless connection suitable for transmitting the compressed information between the central station and the presentation systems. ²⁰ · The device according to claim ¹⁹ ·, with - 79 characterized in that it has a means of transmitting the compressed information to multiple projection rooms for simultaneous presentation in different projection rooms. 21. Apparatus according to claim 19 or 20, characterized in that it comprises means for using a transmission bit rate different from the bit rate used when compressing the information when transmitting the compressed information. 22. The apparatus according to claim 19 or 20, characterized in that it has means for using a transmission bit rate equal to the bit rate used when compressing the information when transmitting the compressed information. 23. Apparatus according to any one of claims 19-22, characterized in that it has means for associating with the compressed information additional checksum information enabling detection of transmitted information blocks containing transmission errors. 24. The apparatus according to any one of claims 19-23, characterized in that the transmission system comprises at least one satellite, and the apparatus has at least one satellite receiver station arranged at the central station in the same location as the central station, which controls the quality of the satellite channel used for transmitting the compressed information and allows its transmission characteristics to be changed in order to maintain the desired quality level. 25. The apparatus according to any one of claims 1-24, characterized in that the central station and the presentation systems enable data exchange. - It has 80 two-way transmission connections. 26. The apparatus of claim 25, characterized in that it has a two-way transmission connection for transmitting data for cryptographic security purposes. 27. The apparatus of claim 25 or 26, characterized in that it has a two-way transmission connection for transmitting data relating to a request for retransmission of compressed information received in error by the presentation systems. 28. The apparatus of claim 27, characterized in that it comprises means for retransmitting compressed information received incorrectly by the presentation systems via the two-way transmission connection. 29. The apparatus according to any one of claims 25-28, characterized in that it has a two-way transmission connection for transmitting data containing control and control signals and commands transmitted between the central station and the presentation systems. 30. The apparatus of any one of claims 1-29, characterized in that it has a network management system for managing a network of presentation systems for presenting the images at authorized times and locations. 31. The apparatus of claim 30, characterized in that it has a network management system for controlling the operation of each presentation system. 32. The method according to any one of claims 1-31. - 81 installations, characterized in that they have presentation systems consisting of movie theaters with at least one projection room. 33. The apparatus of claim 32, further comprising means for transmitting the compressed information to selected screening rooms of a movie theater complex at a given time. 34. The device according to claim 32 or 33, characterized in that there is at least one decoder-decoder unit for each projection room, integrated into the projection equipment of each projection room, preventing theft and illegal copying of images. 35. Apparatus according to claim 14 or any one of claims 15-34, as appended thereto, characterized in that it comprises means for detecting physical intrusion into a projection device of the projection room system and for erasing the encryption key information in the event of such intrusion. 36. The apparatus of claim 32 or any one of claims 33-35, as dependent on the preceding claim, characterized in that at least one movie theater has multiple screening rooms and has a central storage system for delivering compressed information representing a given image program to the various screening rooms at pre-selected, programmable time differences from each other. 37. The apparatus according to claim 36, characterized in that the given image program is provided to each projection room with a substantially zero value, in advance. - It has a storage system that transmits 82 selected, programmable time-shifted images, i.e. essentially providing simultaneous presentation. 38. Apparatus according to claim 32 or any one of claims 33-37, as dependent thereon, comprising a central movie theater storage system for storing compressed information used to generate presentation events for one or more screening rooms. 39. The apparatus of claim 38, characterized in that the movie theater central storage system is formed by a data storage unit shared by several screening rooms. 40. The apparatus of claim 39, wherein the data storage unit comprises a set of magnetic media-based storage devices; and means for using parity information to enable preselected portions of the compressed information to be allocated to different storage devices during storage and to be forwarded to a single presentation location during retrieval. 41. The apparatus of claim 40, wherein the movie theater central storage system includes a means for enabling parallel distribution of received information within the storage unit to achieve the desired data rate and provide redundancy for error protection. 42. The device according to claim 40 or 41, - 83 characterized in that it has a means for storing and reporting to the central station the playback data of the programs legitimately shown in the given screening room. 43. Apparatus according to claim 30 or any one of claims 31-42, as dependent thereon, characterised in that it comprises a cinema control system for controlling and monitoring the operation of the screening rooms of the cinema complex. 44. The apparatus of claim 43, wherein the movie theater control system includes program control means for generating data representing program sets generated from data representing one or more received individual picture programs designated for presentation during an authorized period in the given theater system. 45. Apparatus according to claim 43 or 44, characterized in that it has means for distributing, storing and presenting the programs in a programmable manner controlled by the central station. 46. The apparatus according to any one of claims 43-45, characterized in that it has a means for distributing, storing and presenting the programs in a programmable manner controlled by a control element remote from the central station. 47. The apparatus of any one of claims 43-46, further comprising means for controlling preselected network operations from a location remote from the central station. 48. The method of any one of claims 43-47. - 84 apparatus, characterized in that it has a movie theater local area network system for distributing stored information to one or more screening rooms for presentation to an audience. 49. Apparatus according to any one of claims 1-48, characterized in that it has means for providing the image information in the form of image programs consisting of individual still images or still image sequences or moving images of variable length. 50. The apparatus of any one of claims 1-49, characterized in that the transmission means comprises means for storing the compressed digital information in the central station; means for transferring the stored information to a transportable storage device for physical distribution to the presentation systems; and means for retrieving the information stored on the storage device and transferring it to the storage unit of the presentation system. 51. The apparatus of claim 50, characterized in that it has means for archiving the transportable storage device at the central station. 52. The apparatus of claim 50 or 51, characterized in that it has means for archiving the transportable storage device at the presentation system. 53. Method for distributing digitized image information of the still image or moving image type to display locations, characterized in that the digitized image information is distributed to at least one central - We receive it at 85 stations and compress it according to a pre-selected format; transmitting the obtained compressed image information to one or more remote display systems; storing the transmitted image information for presentation at the presentation systems at least at a preselected time; transmitting the stored compressed image information to one or more decompression systems; the transmitted image information is decompressed in the decompression systems; and the decompressed image information is received at at least one connected projection system and visual images are presented to one or more viewers based on the received information. 54. The method according to claim 53, characterized in that the compressed image and audio information are stored spatially separated from each other. 55. The method according to claim 53 or 54, characterized in that the compression of the information is carried out at a location remote from the central station. 56. The method according to any one of claims 53-55, characterized in that images in digital format are produced using a digital image production system. 57. The method of claim 56, characterized in that the images received from the digital imaging system are acquired by the central station substantially simultaneously with the digitization of the images, - 86 compressed and transmitted to pre-selected, authorized presentation systems. 58. The method according to any one of claims 53-57, characterized in that the compressed image and audio information is stored in the central station for transmission at a later, predetermined time. 59. The method of any one of claims 52-58, characterized in that at least one of the central stations is configured to receive and compress digitized audio information in a predetermined format; further distributing the stored compressed audio information to one or more decompression systems; in the decompression systems, the transmitted audio information is decompressed; and the decompressed audio information is received by at least one connected audio reproduction system, which is presented to one or more listeners based on the received information. 60. The method of claim 59, characterized in that the compression of the digitized audio information is performed at a variable rate. 61. The method according to claim 59 or 60, characterized in that during the desired presentation, in addition to using an identifier enabling the linking of one or more preselected audio programs to at least one preselected image program, audio programs associated with image information separated in time from the associated image are displayed. - 87 we compress and transfer. 62. The method according to any one of claims 59-61, characterized in that audio programs containing several different audio channels are used for presentation during different presentation events of the same image program. 63. The method according to any one of claims 53-62, characterized in that the compression of the digitized image is performed at a variable speed. 64. The method according to any one of claims 53-63, characterized in that the information is encrypted in the central station and the resulting encrypted information is decrypted in the presentation system. ⁶⁵ · ^The method according to claim 64, characterized in that the encryption key information required for decryption of the information by the authorized presentation systems is stored and transmitted separately in time from the transmission of the encrypted information. 66. The method of claim 64, further comprising indicating a time interval in which the encryption key information is valid and ensuring that the encryption key is only used during said time interval. ⁶⁷ The method of claim 66, characterized in that the encryption key information is overwritten in a storage location after the validity time interval has elapsed. 68. The method of claims 53-67, wherein - 88 characterized in that at least one watermark is added to the information, which is not visible when the decompressed image or audio information is presented at a predetermined normal transmission rate, but becomes visible when presented at a rate significantly different from the normal rate. 69. The method of claim 68, characterized in that a watermark identifying the time and location of presentation of the image or audio information is applied. 70. The method according to any one of claims 53-69, characterized in that the compressed information is modulated and transmitted from the central station to the presentation systems via a wireless connection. ⁷¹ · ^{The method according to claim 70} ·, characterized in that by transmitting the compressed information to all or more than one movie theater projection rooms, a presentation is realized in several projection rooms simultaneously using the same information. 72. The method of claim 70 or 71, further comprising using a different transmission bit rate for transmitting the compressed information than that used for compressing the information. 73. The method according to any one of claims 70 or 71, characterized in that the same transmission bit rate as that used for the compression of the information is used for the transmission of the compressed information. 74. The method according to any one of claims 70-73, characterized in that the compressed information - 89 added checksum information is used to detect incorrectly transmitted information blocks. 75. The method according to any one of claims 70-74, characterized in that the signals are transmitted to the presentation systems by means of at least one satellite; and at least one satellite receiving terminal is used at the central station; and by monitoring the quality of the satellite channel used for transmitting the compressed information, the transmission characteristics of the satellite channel are enabled to be modified as necessary to maintain the desired quality level. 76. The method according to any one of claims 53-75, characterized in that a two-way transmission connection is established between the central station and the presentation systems enabling data exchange. 77. The method according to claim 76, characterized in that the exchange of data necessary for implementing cryptographic security measures is performed. 78. The method according to claim 76 or 77, characterized in that the presentation systems request retransmission of compressed information received incorrectly. 79. The method according to claim 78, characterized in that the retransmission of incorrectly received compressed information in the presentation systems is implemented via the two-way transmission connection. 80. The method according to any one of claims 76-79, characterized in that the central station and the presentation - 90 We transfer data containing various control and monitoring signals and commands between systems. 81. The method of any one of claims 53-80, characterized in that a network control system is used to control the network of presentation systems presenting the images at authorized times and locations by controlling the operations of each presentation system. 82. The method according to any one of claims 53-81, characterized in that presentation systems designed as movie theaters with at least one projection room are used. 83. The method of claim 82, characterized in that the compressed information is transmitted to preselected screening rooms within a movie theater complex at a given time. 84. A method according to claim 65 or any of claims 66-88 depending thereon, further comprising detecting physical intrusion into a projection system of a projection room, and deleting information relating to the decryption key upon detection of such intrusion. 85. The method according to any one of claims 82-84, characterized in that the compressed information representing a given image program is transmitted to a plurality of projection rooms of a movie theater complex with preselected, programmable time offsets. 86. The method of claim 85, wherein the preselected programmable time offsets are reduced to substantially zero and the given image program is delivered to each projection room substantially simultaneously. 87. The method of claim 82 or 83, wherein the compressed information used to generate presentation events in one or more screening rooms is stored in a central movie theater storage system. ⁸⁸ · ^{The method according to claim 87} , characterized in that a unit consisting of magnetic storage devices is used as the central storage system for the movie theater. ⁸⁹ · ^{The method of claim 88} , further comprising using parity information to associate different preselected portions of the compressed information to different storage devices upon storage and to link them to a single representation upon retrieval. 90. The method according to claim 88 or 89, characterized in that the desired data transfer rate and error protection redundancy are ensured by distributing the received information in parallel among the individual devices of the storage unit. 91. The method according to any one of claims 88-90, characterized in that data relating to the presentation order of the authorized programs presented in the given screening room are stored and reported to the central station. 92. The method of any one of claims 53-91, characterized in that program sets are formed within the movie theater control system from one or more received individual video and audio programs designated for presentation in a screening room system during an authorized time interval. ⁹³ · ^{The method according to claim 92} , characterized in that the programs are automatically distributed, stored and presented under programmable control implemented by the central station. 94. The method of claim 92 or 93, characterized in that the control of certain, preselected network operations is performed from a location remote from the central station. 95. The method of any one of claims 92-94, characterized in that the stored information is distributed to one or more projection room systems via a movie theater local area network system for presentation to viewers. 96. The method according to any one of claims 53-95, characterized in that the image information is produced in the form of image programs consisting of individual still images or a series of still images or moving images of variable length. 97. The method according to any one of claims 53-96, characterized in that during transmission the compressed digital information is stored in the central station; the stored information for presentation systems - 93 is physically transferred to a transportable storage device for distribution; and the information stored on the transportable storage device is transferred to the storage system of the presentation system after extraction. ⁹⁸ · ^{The method according to claim 97} ·, characterized in that the storage device is archived in the central station. · ^{The method according to claim 97} , characterized in that the storage device is archived in the presentation system. 100. Apparatus for transmitting data representing images to selected locations, characterized in that the input of the image data receiver; a data compressor that compresses image data; a data cipher that encrypts image data, adds information identifying selected locations to the encrypted data, and requires knowledge of encryption key data to decode the data; and a transmitter that transmits the encrypted data over a transmission medium; and the encryption system is configured to ensure that the data defining the encryption key is transmitted independently of the encrypted data. 101. The apparatus of claim 100, characterized in that the transmitter transmits the data defining the encryption key separately in time from the encrypted data. - It's 94. 102. The apparatus of claim 100 or 101, characterized in that it comprises a unit for permitting the presentation of the image at a selected location for a predetermined period of time and a transmitter for transmitting the encryption key immediately before the beginning of the permitted period. 103. The device according to claim 102, characterized in that it has a unit for issuing a cryptographic key limiting the possibility of presentation to a predetermined period of time. 104. The apparatus according to any one of the preceding claims, characterized in that it has means for transmitting the encrypted data via a broadcast channel. 105. The apparatus of any one of the preceding claims, characterized in that it has means for transmitting the encryption key via a medium different from the transmission medium. 106. The apparatus according to any one of the preceding claims, characterized in that it has an encryption unit for adding a watermark to the encrypted data. 107. The apparatus of claim 106, characterized in that it has an encryption unit for adding a watermark containing a location-specific and/or time-specific identifier to the encrypted data at pseudo-random positions of the images. 108. The apparatus of claim 107, further comprising an encryption unit for adding to the encrypted data a watermark identifying the authorized location and time of presentation of the images represented by the encrypted data. 109. The apparatus of any preceding claim, further comprising a transmitter for transmitting the encrypted data via a broadcast transmission channel. 110. The apparatus according to any one of the preceding claims, characterized in that it has a transmitter transmitting the encrypted data at a transmission rate dependent on the parameters of the image they represent and the parameters of the transmission channel. 111. Apparatus for displaying images represented by data transmitted via a transmission channel, characterized in that it comprises a unit for receiving encrypted data transmitted via the transmission channel representing the images to be displayed, and data representing a cryptographic key; a decoder that decrypts the encrypted data using the encryption key; multiple display devices; and a distribution network for delivering the decoded data to selected display devices during a display event. 112. The device according to claim 111, characterized in that it has a unit for receiving the data defining the encryption key separately in time from the encrypted data. 113. The apparatus of claim 111 or 112, characterized in that the means for providing an encryption key limiting the possibility of playback to a predetermined period of time, and the means for encrypting the data with this encryption key - 96 has a decoder that decodes exclusively during the predetermined period of time. 114. The apparatus according to any one of claims 111-113, characterized in that it comprises means for selectively receiving the encrypted data via the transmission channel. 115. The apparatus according to any one of claims 111-114, characterized in that it comprises means for receiving the encryption key via a medium different from the transmission channel. 116. The apparatus according to any one of claims 111-115, characterized in that it has a control processor measuring the parameters of the received signal and issuing a request for retransmission of a portion of the encrypted data when these parameters fall below predetermined values. 117. The apparatus according to any one of claims 111-116, characterized in that it has a control processor for checking by comparison the digital markings embedded in certain parts of the encrypted data and requesting retransmission of certain parts in case of detection of erroneous digital markings. 118. The apparatus of claim 117, further comprising a control processor for replacing portions of the encrypted data containing an incorrect designation with retransmitted portions containing a correct digital designation. 119. The apparatus according to any one of claims 111-117, characterized in that the decoded data is - It has 97 storage units for distribution to selected presentation devices. 120. The apparatus according to any one of claims 111-119, characterized in that it has a means for distributing the data for simultaneous presentation of the images on multiple display devices. 121. The apparatus according to any one of claims 111-119, characterized in that it has a means for distributing the data for presenting the images on a plurality of display devices in a time-separated manner. 122. The apparatus of claims 113 and 119, characterized in that it comprises a storage unit for storing the encrypted data before the predetermined period, and a decoder for decoding the stored encrypted data for displaying the images represented by them during the predetermined period. 123. The apparatus according to any one of claims 111-122, characterized in that it has a means for recording data relating to the course of presentation events. The authorized representative: advocate PATENT AND TRADEMARK OFFICE VARANNAI CSABA patent attorney