JPH09247647A - Video audio information delivery system - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] Digitally deliver desired video / audio information in a compressed video / audio data format such as MPEG2 in response to a request from a viewer, and perform video on / off by a simple program selection method.
It is to provide an audiovisual information distribution system that realizes a demand service. SOLUTION: A video server, a system control device, a bidirectional transmission path, and a receiving terminal are provided, and a desired program is transmitted from the video server to a compressed video and audio such as MPEG2 in response to a program request from the receiving terminal in the system control device. In addition to controlling to send in the data format, the receiving terminal is notified of the program selection information necessary for viewing the requested program. It is possible to greatly simplify the processing of the entire system and provide the video-on-demand service to the viewer very stably without the system breaking down even if the program requests from the viewer concentrate for a period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for delivering video / audio information of a movie or the like, and more particularly, to a desired video / audio information in accordance with a request from a viewer.
The present invention relates to a video / audio information distribution system suitable for realizing video-on-demand services by digitally distributing compressed video / audio data formats such as Picture Experts Group Phase2).

[0002]

2. Description of the Related Art Against the backdrop of standardization of MPEG2, which is a highly efficient video and audio compression technology, a new digital broadcasting service combining this MPEG2 video and audio compression technology and communication satellites has been launched in the United States, and soon in Japan. Situation. In consideration of application to digital broadcasting, the MPEG2 standard defines a transport stream (hereinafter referred to as TS) that transmits a plurality of programs by time division multiplexing. As a result, in conventional analog broadcasting, only one program can be broadcast by one transponder (one channel) of a communication satellite, whereas in digital broadcasting using MPEG2-TS, a plurality of programs (for example, 4 to 8 programs) It became possible to broadcast by time division multiplexing. Therefore, in the conventional analog broadcasting, the viewer can watch the desired program only by selecting the channel in the tuner of the receiving terminal, while in the digital broadcasting using MPEG2-TS, the channel selection After that, it becomes necessary to further select and separate a desired program from a plurality of programs time-division multiplexed in the MPEG2-TS format on the selected channel and transmitted.

For a method of selecting a program in MPEG2-TS and digital broadcasting using the MPEG2-TS, refer to The Television Society Journal Vo.
l.49, No.4, pp480-489 (1995). The outline is described below.

FIG. 11 schematically shows MPEG2-TS. MPEG2-
The TS is a TS with a fixed length of 188 bytes as shown in FIG.
It is composed of packets, and one MPEG2-TS is transmitted by one transponder (for example, channel 61) of a communication satellite. A TS packet is composed of a packet header and a data area, and the packet header has information such as a packet identifier PID (Packet Identifier) described later beginning with a synchronization pattern. In addition, in the data area, the figure (b)
Various data shown in are stored in TS packet units. As an example, FIG. 2B shows various data transmitted as MPEG2-TS when two programs per channel are time-division multiplexed and broadcast. Program data is
Video and audio data of each program that is time-division multiplexed and broadcast,
Specifically, MPEG2 video data corresponding to each program, M
This is PEG2 audio data. PSI (Pragram Specifi
c Information) data is information for easily selecting the program at the receiving terminal, and specifically, PAT (P
rogram Association Table), PMT (P
rogram Map Table), NIT (Network Information Tabl)
e) etc. These program data and PSI data,
As shown in (b) of the figure, a unique PID is assigned to each and time-division multiplexed in TS packet units. For this reason, TS
By the PID of the packet, the data type stored in the data area of the TS packet can be identified.

FIG. 12 shows the specific contents of information described in PAT, PMT, and NIT and the link relationship. As with FIG. 11, two programs are MPEG2-based on one channel (channel 61).
An example of time-division multiplexing and broadcasting as TS is shown. PA
The T, PMT, and NIT have a hierarchical structure as shown in FIG. PID is fixedly assigned to PAT according to the MPEG2 standard. Further, all the programs which are time-division multiplexed and broadcast in the MPEG2-TS are assigned program numbers as program identification information. This program number can be arbitrarily set by the broadcaster for each program. PA
In T, PIDs of PMTs corresponding to all programs time-divisionally multiplexed and broadcast in the MPEG2-TS are described in pairs with the program numbers. In the example shown in FIG. 12, the PID (= “1”) of the PMT corresponding to the program 1 with the program number “1” and the program number “2”
The PMT PID (= “2”) corresponding to the program 2 marked with is described. In addition, the PAT describes the PIT of NIT. MPE
According to the G2 standard, the program number “0” is fixedly assigned to the NIT, so the PID of the NIT is described in pairs with the program number “0”. The PMT exists for each program and is hierarchically located below the PAT. Therefore,
In the example of FIG. 12, the PMT of program 1 and the PMT of program 2 exist. In the PMT of each program, the PID of the TS packet in which the video and audio information forming the program is transmitted is described together with the program number unique to each program. As described above, the details of the data structure of PAT and PMT are defined by the MPEG2 standard. Next, NIT is hierarchically similar to PMT in PA.
Located under T. The NIT describes physical information about the transmission path, but details of the data structure are not defined by the MPEG2 standard and are defined by the user. However, in digital broadcasting using MPEG2-TS, NIT is indispensable for realizing the program selection function at the receiving terminal, and in general, at least the number and frequency of the transponder (in other words, channel) on which each program is broadcast is set. Information is described. Figure 1 shows a specific example of NIT.
As shown in 2, a program number unique to each program and a channel number on which the program is broadcast are described as a pair. As is clear from the above description, PAT and PMT correspond to the MPEG2-TS
(In other words, the information about the program broadcast on the channel 61 in this specific example) is described, and is different for each channel. On the other hand, the NIT has a program number and a channel number as a pair not only for the program broadcast on the MPEG2-TS (channel 61) but also for the programs of all other channels being broadcast as shown in FIG. Has been described. Therefore, the NIT transmits the same table information on all channels.

The outline of MPEG2-TS and PSI has been described above. Next, a conventional example of a program selection method based on PSI is shown in FIG.
This will be described with reference to FIG. FIG. 13 is a program selection flowchart showing a procedure in which a viewer selects a program at the receiving terminal.
The MPEG2-TS and PSI shown in FIGS. 11 and 12 will be described below as specific examples.

(Step 221) The viewer inputs a program number (= "1") unique to a desired program (for example, program 1 in FIGS. 11 and 12) to the receiving terminal by a user interface such as a remote controller. The program list information such as the programs to be broadcast and the program numbers unique to each program are printed materials or electronic program guide EPG (Elect
ronic Program Guide) is provided to viewers in advance.

(Step 222) The receiving terminal uses the channel currently selected by the tuner (for example, channel 6).
In 1), referring to the PID of each TS packet, PID =
Only the TS packet of "0" is separated and the PAT of the relevant channel (channel 61) is received.

(Step 223) The received PAT is searched for the program number (= "1") input by the viewer in step 221. If the program number exists, the process of step 226 is performed. If it does not exist, the process of step 224 is performed.

(Step 224) In the received PAT, if the above program number does not exist, the PID of the NIT described as a pair with the program number "0" (see FIG. 12).
In the example shown in, “10”) is acquired. Then, for each TS packet on the channel (channel 61)
The PID is referred to, only the TS packet with PID = “10” is separated, and the NIT is received. In the received NIT, the viewer retrieves the channel number on which the program of the program number input in step 221 is broadcast, and changes the channel selected by the tuner.

(Step 225) After changing the channel selected by the tuner, the PID of each TS packet is referred to, and PID = "0".
Only the TS packet of is separated and the PAT of the relevant channel is received.

(Step 226) In the received PAT, the PMT PID (“11” in the example shown in FIG. 12) corresponding to the program number (= “1”) input by the viewer in step 221 is acquired. Then, in the channel (channel 61), the PID of each TS packet is referred to, only the TS packet of PID = “11” is separated, and the PMT corresponding to the program number is received.

(Step 227) In the received PMT, MPEG2 corresponding to the program number (= "1")
Video data and audio data (in the example shown in FIG. 12, "13" and "14", respectively) are acquired. Then, in the channel (channel 61), based on these PIDs, TS packets of MPEG2 video data and audio data corresponding to the desired program selected by the viewer are separated and combined by an MPEG2 decoder.

As is clear from the above description, MPEG2-TS
In, it is devised so that the desired program can be selected based on the PSI data by time-division multiplexing and transmitting the audiovisual data and the PSI data of a plurality of programs.

On the other hand, in addition to the above digital broadcasting service,
Video-on-demand (hereinafter referred to as VOD) service is drawing attention as an application service of MPEG2. VOD
A video and audio information distribution system that realizes services,
It is composed of a video server, a bidirectional transmission path, a receiving terminal, and a system control device, and appropriately distributes a desired program in response to a request from a viewer. Currently, MPEG1 (Mov
ing Picture ExpertsGroup Phase1) Most of them use the standard, but in the future, like the digital broadcasting service, the MPEG2 standard is used, and the development of a system for digitally distributing MPEG2-TS is becoming more active.

[0016]

However, in a video / audio information distribution system (hereinafter referred to as a video / audio information distribution system) that digitally distributes MPEG2-TS from a video server to a receiving terminal and provides a VOD service or the like, If the program selection method based on PSI data similar to digital broadcasting is applied, the following problems will occur.

In the case of the above digital broadcasting, a broadcasting company sets a program broadcasting schedule in advance. Thus, broadcasters, in advance which program channel to which the time division multiplexing can fixedly determines to transmit, to be transmitted corresponding to the broadcast schedule previously prepared a PSI uniquely determined on the receiving terminal it can. Therefore, the viewer was able to select a desired program based on the PSI data from the programs commonly broadcast to all receiving terminals according to the program broadcast schedule. On the other hand, in the video / audio information distribution system that provides the VOD service, every time a viewer requests a program, an empty channel to which the program has not been distributed must be searched for and distributed. Fluctuates from moment to moment. Therefore, in the video / audio information distribution system that provides the VOD service, it is necessary to appropriately change the PSI each time a program request from a viewer is accepted, in accordance with the program distribution status that changes from moment to moment. At this time, when a plurality of viewers request the same program, even if the program contents are the same, the program numbers must be assigned as different programs and the PSI must be changed.

As is clear from the above description, in the above-mentioned video / audio information distribution system which provides the VOD service, there is a problem that the PSI changing process which is extremely complicated and requires a huge amount of processing must be processed at high speed in real time. Furthermore, when the program requests from the viewers are concentrated,
PSI change processing cannot be performed in real time, and the program distribution status and P
There is a problem that the SI does not match with the SI and the viewer cannot watch the desired program on the receiving terminal.

An object of the present invention is to provide a video / audio information distribution system which allows a viewer to always stably select and view a desired program without performing the above-described complicated PSI changing process.

[0020]

In order to achieve the above object, the video / audio information distribution system of the present invention stores the compressed video / audio data of each program to be distributed, and stores the compressed video / audio data of each program in a multiplicity N. (N is an integer greater than or equal to 1) MPEG2-TS format video server, and the viewer requests a desired program using a remote controller, etc., receives the program delivered from the video server, and receives compressed video and audio of the requested program. The receiving terminal for decompressing and displaying the data, the reception of the program request from the receiving terminal, the instruction to send the program to the video server, the transmission of the program selection information to the receiving terminal, etc. are performed to control the entire audiovisual information distribution system of the present invention Information such as MPEG2-TS of each program sent from the system control unit and the video server, program requests from the receiving terminal, and program selection information from the system control unit are stored. Constituted by a bidirectional transmission path for transmitting at a modulation scheme.

Here, the video server respectively stores a compressed video / audio data storage unit for storing compressed video / audio data of each program to be distributed, and compressed video / audio data of each program read from the compressed video / audio data storage unit. A multiplexing unit that sends program identification information in the MPEG2-TS format with a multiplicity N (N is an integer of 1 or more), and server control that controls the operations of these compressed video and audio data storage unit and multiplexing unit. Section.

Further, the receiving terminal has a program receiving section for selecting a desired channel from a plurality of channels and demodulating a program modulated by a predetermined modulation method, and an MPEG2-TS having multiplicity N.
, A separation unit for separating compressed video data and compressed audio data corresponding to a desired program from the
A program request command is issued between the compressed video and audio data decompression unit that decodes the compressed audio data and decompresses it into the original video and audio signal, the operation command input unit through which the viewer inputs commands such as program selection, and the system control device. Bidirectional communication unit for transmitting bidirectionally, program selection information, etc.
The terminal control unit that controls the operations of the demultiplexing unit, the compressed video / audio data decompression unit, the operation command input unit, the bidirectional communication unit, and the like is provided.

Further, the system control device bidirectionally receives the program request command and notifies the program selection information to and from the receiving terminal via the bidirectional transmission path, and connects to the video server. The server communication unit that notifies the program distribution command and acquires the operating status information of the video server, etc., and centrally manages the distribution of the program based on the program request status from the receiving terminal and the operating status of the video server, and sends it to the video server. And a system control unit for issuing a program distribution command, program selection information to the receiving terminal, and the like.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram of a video / audio information distribution system of the present invention which provides a VOD service using MPEG2-TS. In FIG. 1, reference numeral 10 denotes MPEG2-, which stores compressed video / audio data of each program and has a multiplicity N (N is an integer of 1 or more).
Video servers for transmitting in the TS format, receiver terminals 20, 30, 40 for receiving a program distributed from the video server 10 by a viewer requesting a desired program with a remote controller or the like.
0 receives a program request from the receiving terminals 20, 30, 40, issues a program sending command to the video server 10 and sends program selection information to the receiving terminals 20, 30, 40, etc. A system control device for controlling the whole, 60 is a bidirectional transmission path for transmitting a program distributed from the video server 10, a program request command from the receiving terminals 20, 30, 40, program selection information from the system control device 50, and the like, Reference numerals 61, 62 and 63 denote MPEG2 with multiplicity N output from each output terminal of the video server 10.
-A digital modulator that digitally modulates TS at different frequencies by a modulation method such as 64QAM, VSB, QPSK, and 65 mixes or demultiplexes the modulation signals from the digital modulators 61, 62, 63 and the system controller 50. The bidirectional mixing / branching device 66 is a coaxial or optical cable.

Further, as shown in FIG. 2, the video server 10 in FIG.
G2 PES (Packetized Elementary Stream) or PS (P
rogram stream) or compressed video / audio data of each program compressed in the TS format of multiplicity 1 and stored in a separate file for each program, and read from the compressed video / audio data storage unit 11. Multiplexing units 12, 13, 14 for time-division multiplexing compressed video / audio data in MPEG2-TS format with multiplicity N (N is an integer of 1 or more) and a server control unit 15 for controlling the operation of the video server 10. Composed.

Further, as shown in FIG. 3, the receiving terminal 20 in FIG. 1 has a digital tuner section 22 for selecting a desired channel from a plurality of channels for transmitting the program, and a digitally modulated program. A digital demodulation unit 23 for demodulating the compressed video data, a separation unit 24 for separating compressed video data and compressed audio data corresponding to a desired program from MPEG2-TS having a multiplicity N, and decoding the separated compressed video data and compressed audio data. A compressed video / audio data expansion unit 25 (for example, an MPEG2 decoder) that expands the original video / audio signal, and a video display unit 26 (for example, a display) that displays the video signal.
A voice output unit 27 (for example, a speaker) that outputs the voice signal, and a bidirectional communication unit 28 for bidirectionally transmitting a program request, program selection information, and the like between the system control device 50, and a receiving unit. A terminal control unit 29 for controlling the operation of the entire terminal, an operation command input unit 100 (for example, a remote controller) for a viewer to input a command such as a program selection to the receiving terminal 20, and a program list stored in the video server 10. And a program guide generation unit 110 for providing the program selection menu to the viewer via the video display unit 26. The digital tuner section 22 and the digital demodulation section 23 are collectively referred to as a program receiving section 21.

The system controller 50 shown in FIG.
Specifically, as shown in FIG. 4, the receiving terminals 20, 30,
A terminal communication unit 51 for receiving a program request from the terminal 40 and transmitting program selection information to each of the receiving terminals 20, 30, 40.
And a server communication unit 52 that transmits a server control command and receives server operation information and the like, and comprehensively grasps a server operation state, a program request and a program reception state of a receiving terminal, and a desired program on a predetermined channel. The system control unit 53 controls the entire system so that the information is appropriately distributed.

Based on the above, the outline of the operation of the video / audio information distribution system of the present invention shown in FIGS. 1 to 4 will be described with reference to a program selection and reception flow chart in the video / audio information distribution system shown in FIG.

(Step 501) The viewer selects a desired program from the programs stored in the compressed video / audio data storage unit 11 in the video server 10 at the receiving terminal 20, for example. Specifically, in the receiving terminal 20 of FIG. 3, the viewer outputs a program selection menu output from the program guide generation unit 110 based on a command from the terminal control unit 29 and displayed via the video display unit 26 (see FIG. A desired program is selected from (an example of a menu screen), and the number corresponding to each program is input by the operation command input unit 100 such as a remote controller. For example, when the viewer selects “program B” from the program selection menu, the program number “2” is input from the operation command input unit 100.

(Step 502) The receiving terminal 20 receives the program number input from the operation instruction input section 100 and sends a program request instruction to the system control device 50. Specifically, the program number input from the user command input unit 29 is supplied to the terminal control unit 29, and the terminal control unit 29 controls the program request command via the bidirectional communication unit 28 using a predetermined communication protocol. Send to device 50. This program request command includes at least receiving terminal identification information (hereinafter referred to as receiving terminal ID) and program identification information of the requested program (hereinafter referred to as program ID). The receiving terminal ID is information for distinguishing a plurality of receiving terminals connected to the system control device 50, and a receiving terminal ID different for each receiving terminal (for example,
Receiving terminal number) is assigned. Also, the program ID
Is a compressed video and audio data storage unit 1 in the video server 10.
This is information for distinguishing each of the programs stored in 1, and a program ID (for example, a file name) is assigned so as to have a one-to-one correspondence with the stored programs. As a specific example, in the present embodiment, the receiving terminal ID of the receiving terminal 20 is “1”, and the program ID of “program B” is “MOVIE B”.

(Step 503) System controller 50
Receives the program request command transmitted from the receiving terminal 20. Specifically, the program request command transmitted from the receiving terminal 20 is the coaxial or optical cable 6
6, input to the terminal communication unit 51 of the system control device 50 via the bidirectional mixing / branching device 65. Terminal communication unit 51
From the program request command sent by the predetermined communication protocol, the receiving terminal ID “1” and the program ID “MOVIE
"B" is recognized and the system control unit 53 is notified.

(Step 504) System controller 50
The system control unit 53 has a distribution management table shown in FIG. 7A, and at least the operating status of whether or not each output terminal of the video server 10 is being distributed, and the distribution program ID when distribution is being carried out. It manages the destination receiver terminal ID, PID assigned to the MPEG video data and audio data corresponding to the delivered program, and so on. The example shown in FIG. 7A is an MPEG output from each output terminal of the video server 10.
This is the case where the multiplicity of 2-TS is 2. Also, the video server 1
The output terminals of 0 are connected to the digital modulators 61, 62 and 63 having different modulation frequencies as shown in FIG. Therefore, as shown in FIG. 7A, a channel for uniquely transmitting a program is assigned to each output terminal of the video server 10, and two programs per channel are time-division multiplexed in the MPEG2-TS format. Transmitted. Two programs transmitted on the same channel can be identified and separated by the PID. That is, this PID
Plays a role of identification information for identifying MPEG video data and audio data of a desired program from an MPEG2-TS in which a plurality of programs are time-division multiplexed. Figure 7
In the system control unit 53, each piece of information in the distribution management table of (a) is a program distribution such as when a program request command is transmitted from the receiving terminals 20, 30, 40, or when the operating status of the video server 10 changes. It is updated sequentially when the status changes. The operating status of the video server 10 in each piece of information in the distribution management table is acquired from the video server 10 via the server communication unit 52 of the system controller 50.

System controller 5 of system controller 50
3 is the video server 1 according to the distribution management table.
The program distribution status from 0 is checked, and an empty output terminal to which the program can be newly distributed is searched. Then, the output terminal (in other words, channel) of the video server 10 to which the "program B" requested by the receiving terminal 20 is distributed is determined. In the example shown in FIG. 7A, since the output terminals “1” and “2” are vacant, it is determined to deliver from the output terminal “2” (that is, the channel 62), for example. Further, the system control unit 53, based on the delivery management table, sends MPEG2 corresponding to each program currently being delivered.
PID assigned to video and audio data
To determine the PID to be assigned to the MPEG video data and audio data of the "program B" distributed from the output terminal "2" so as not to overlap with this. In the example shown in FIG. 7A, since PIDs “1” to “8” are assigned to programs already being distributed, for example, MPEG2 video data of “program B” distributed from the output terminal “2”. PIDs “9” and “10” are assigned to the audio data and the audio data, respectively.

By the way, in a video / audio information distribution system such as the present invention which provides a VOD service, a situation occurs in which the same program is simultaneously distributed to a plurality of receiving terminals at different start timings. That is, in the example shown in FIG. 7 (a), when "Program B" is newly delivered from the output terminal "2" to the receiving terminal 20 having the receiving terminal ID "1", the receiving terminal is delivered from the output terminal "3". There is a situation in which "program B" has already been delivered to the receiving terminal with ID "4". In the video / audio information distribution system such as the present invention which provides the VOD service, the receiving terminal 20 having the receiving terminal ID “1” and the receiving terminal ID
"Program B" delivered to each "4" receiving terminal is
Since the requested viewer and the requested time are different, it is necessary to control distribution as different programs even though they have the same program content. Therefore, as described above, it is necessary to assign different PIDs to the MPEG2 video data and audio data of all programs being distributed, even if they have the same program content. This is an MPEG2 program in which there is a one-to-one relationship between the program content and the PID assigned to the MPEG2 video data and audio data of the program.
-It is a big difference from digital broadcasting using TS.

(Step 505) System controller 50
Transmits a distribution instruction of “program B” requested from the receiving terminal 20 to the video server 10. Specifically, the system control unit 53 of the system controller 50 outputs the "program B" determined in step 504 to the output terminal "2" of the video server 10 and the program ID "MOVIE B" of the "program B".
Also, the PIDs “9” and “10” assigned to the MPEG2 video data and audio data of “Program B” are transmitted to the server control unit 15 of the video server 10 via the server communication unit 52 by a predetermined communication protocol.

(Step 506) The server controller 15 of the video server 10 receives the distribution instruction of the request program transmitted from the system controller 50, and outputs the output terminals "2" and "program B" of the video server 10. Program ID "MOVIE
The PIDs “9” and “10” assigned to the MPEG2 video data and audio data of “B” and “Program B” are recognized.

(Step 507) The video server 10
Based on the control command from the server control unit 15, the PID designated from the designated output terminal "2" for the MPEG2 video data and audio data of the requested program "Program B"
It is sent in the MPEG2-TS format with "9" and "10" added. Specifically, the server control unit 15 of the video server 10 writes the file name “MOVIE” to the compressed video / audio data storage unit 11.
It is instructed to read the compressed video / audio data stored in the B format and in the PES or PS of MPEG2 or the TS format of the multiplicity of 1 and supply it to the multiplexing unit 13 of the output terminal "2". The server control unit 15 also instructs the multiplexing unit 13 to attach the designated PIDs “9” and “10” to the MPEG2 video data and audio data of “program B”, respectively. Further, the server control unit 15 transmits to the system control device 50 in accordance with a predetermined communication protocol as a transmission notification of the request program that the request program “Program B” is transmitted from the output terminal “2”. The compressed video / audio data storage unit 11 outputs the compressed video / audio data of the request program “program B” to the multiplexing unit 13 based on the instruction. The multiplexing unit 13 uses the supplied request program “program
The compressed video and audio data of “B” are time-division multiplexed in the MPEG2-TS format with the multiplicity of 2. At this time, the multiplexing unit 13
PIs specified for the MPEG2 video data and audio data of "Program B" that are time-division multiplexed in MPEG2-TS format
D Operates to add "9" and "10". As a result, from the output terminal “2” of the video server 10, the MPEG2 video data and audio data of “Program B” to which the PIDs “9” and “10” are assigned respectively are MPEG of the multiplicity of 2.
It is sent in 2-TS format. At this time, in the example shown in FIG. 7A, from the output terminal “2” of the video server 10 to the receiving terminal with the receiving terminal ID “3” together with the MPEG2 video data and audio data of the “program B”. On the other hand, the MPEG2 video data and audio data (PID “3”, “4”) of “program C (program ID“ MOVIE C) ”are time-division multiplexed and transmitted. In the video / audio information distribution system of the present invention which provides the VOD service using MPEG2-TS, the PSI is not time-division-multiplexed with the MPEG2-TS sent from the video server 10, and this is the point of the MPEG2-TS. This is a major difference from digital broadcasting using. That is, in the video / audio information distribution system of the present invention, the video server 10 reflects the program distribution state which changes moment by moment in response to the program request from the receiving terminals 20, 30, 40.
The PSI is not generated at all, and the specified PID is simply added to the transmitted MPEG2 video data and audio data to generate the MPEG2-TS with the multiplicity of 2, which greatly simplifies the processing. The MPEG2-TS of “Program B” transmitted from the output terminal “2” of the video server 10 is supplied to the digital modulation device 62 and digitally modulated at the frequency corresponding to the channel 62. The “Program B” MPEG2-TS digitally modulated by the digital modulator 62 is transmitted to the “Program B” via the bidirectional mixing / branching device 65 and the coaxial or optical cable 66.
Is transmitted to the receiving terminal 20 which has requested.

(Step 508) System controller 50
Receives the transmission notification of the requested program transmitted from the video server 10 at the server communication unit 52 and notifies the system control unit 53 of the notification. The system control unit 53 changes the distribution management table shown in FIG. 7A to reflect the current distribution status based on the notification of the transmission of the requested program. Specifically, as shown in FIG. 7B, the operation status of the output terminal number “2” of the video server 10, the distribution program ID,
Delivery destination receiving terminal ID, PID attached to MPEG2 video data and audio data, respectively, "during delivery", "MOVIE
Change to "B", "1", "9", "10", and generate the latest distribution management table based on the current distribution status.

(Step 509) System controller 50
The system control unit 53 transmits the program selection information to the receiving terminal 20 which is the distribution destination of the "program B", together with the change of the distribution management table. In the video / audio information distribution system of the present invention, unlike digital broadcasting using MPEG2-TS as described above, PSI is not time-division multiplexed with MPEG2-TS sent from each output terminal of the video server 10. For this reason,
In the video / audio information distribution system of the present invention, each receiving terminal 2
At 0, 30, and 40, the requested program cannot be selected and separated by the program selection procedure using the PSI of FIG. Therefore, in the video / audio information distribution system of the present invention, each of the receiving terminals 20 and 3 from the system controller 50.
Program selection information in place of PSI is transmitted to 0 and 40. Specifically, from the system control unit 53 of the system control device 50 to the receiving terminal 20 which is the distribution destination of the "program B", the distribution of the "program B" together with the receiving terminal ID "1" which is the receiving terminal identification information. Channel information (that is, channel number "62" or specific modulation frequency of channel number "62") and PID ("9", "10") assigned to MPEG2 video data and audio data
Is notified as program selection information. The program selection information output from the system control unit 53 is transmitted to the receiving terminal 20 by a predetermined communication protocol via the terminal communication unit 51, the bidirectional mixing / branching device 65, the coaxial cable or the optical cable 66.

(Step 510) The receiving terminal 20 receives the receiving terminal ID "1" transmitted from the system controller 50.
And receive the program selection information. Specifically, the receiving terminal 20
In the two-way communication unit 28 of, from the receiving terminal ID “1” and the program selection information sent by the predetermined communication protocol,
Distribution channel number "62" of "Program B", or concrete modulation frequency and MPEG2 of channel number "62"
PID assigned to video data and audio data
It recognizes ("9", "10") and notifies the terminal control unit 29 of it.

(Step 511) The terminal control unit 29 of the receiving terminal 20 notifies the above-mentioned channel number "62",
Alternatively, the digital tuner unit 22 is instructed to select the channel number "62" based on the specific modulation frequency of the channel number "62". At the same time, based on the PID (“9”, “10”) assigned to the MPEG2 video data and audio data of the “program B” notified above,
The demultiplexing unit 24 is instructed to separate the packets with PIDs "9" and "10" from the MPEG2-TS of multiplicity 2. The digital tuner unit 22 receives the “program” transmitted from the video server 10 on the channel 62 based on the above command.
Select "B". The “program B” selected by the digital tuner unit 22 is demodulated by the digital demodulation unit 23, and “program B” is displayed.
The MPEG2-TS having a multiplicity of 2 including “B” is supplied to the demultiplexing unit 24. In the program distribution example shown in FIG. 7B, the separation unit 2
MPEG2-TS of multiplicity 2 supplied to PID 4 has PID “9”,
Time-division multiplexed MPEG2 video data and audio data of "Program B" with "10" and MPEG2 video data and audio data of "Program C" with PID "3" and "4". is there. The demultiplexing unit 24 selects the PID from the MPEG2-TS of severity 2 supplied based on the above command.
Packets with "9" and "10" are separated, and "program
Only the “B” MPEG2 video data and audio data are output to the compressed video / audio data decompression unit 25. Compressed video / audio data decompression unit 25 (specifically, MPEG2-decoder)
Is an analog capable of displaying and outputting the input MPEG2 video data and audio data of “Program B” on the video display unit 26 (specifically, a display or the like) and the audio output unit 27 (specifically, a speaker or the like). It is decoded into a video signal (for example, NTSC signal) and an analog audio signal. As a result, the viewer sees the video display unit 26 and the audio output unit 2
7, you can watch "Program B".

The outline of the operation of the video / audio information distribution system of the present invention for providing the VOD service using MPEG2-TS has been described above. As is clear from the above description, in the video / audio information distribution system of the present invention, the viewer receives the receiving terminals 20, 3.
In order to view a desired program at 0 and 40, the program distribution state that changes momentarily in MPEG2-TS sent from each output terminal of the video server 10 in response to a program request from the receiving terminals 20, 30 and 40 No complicated and enormous processing of time-division-multiplexing the corresponding PSI is performed at any time. That is, in the video / audio information distribution system of the present invention, the MPEG2 video data and the audio data of the request program are attached to the receiving terminals 20, 30, 40 in the MPEG2-TS format by simply attaching the designated PID as identification information.
To the receiving terminal 20, 30, 40 by sending the above program selection information to the receiving terminals 20, 30, 40 instead of PSI at the same time, the viewer can view the desired program, greatly simplifying the process and requesting the program from the viewer. It is possible to provide the VOD service to viewers in a very stable manner even when concentrated for a period of time. Also,
In the receiving terminals 20, 30 and 40, it is necessary to select the desired program after separating the desired program after receiving the PSI that is time-division-multiplexed and transmitted in MPEG2-TS in digital broadcasting and acquiring the information necessary for program selection. However, in the video / audio information distribution system of the present invention, the program selection information is sent to the receiving terminals 20, 30, 40 separately from the MPEG2-TS in which the request program is time-division multiplexed. , MPEG when receiving the program
Since it is not necessary to separate and recognize the PSI from the 2-TS, the program reception selection processing of the receiving terminals 20, 30, 40 can be simplified.

By the way, in the above embodiment of the present invention,
As described in FIG. 7 and step 504, when the system control device 50 receives the program request command from the receiving terminals 20, 30, 40, the MPEG2 video data and audio data corresponding to each program currently being distributed. Search the PID assigned to, and make sure it does not overlap with this.
The PID of the MPEG video data and audio data of the newly distributed program was decided. Also, the system controller 5
From 0 to the receiving terminals 20, 30, 40, together with the receiving terminal ID which is the receiving terminal identification information as the program selection information, the program distribution channel information (that is, the channel number or a specific modulation frequency of the channel number) and the MPEG.
2 PID assigned to video data and audio data
Was sent, but the following may be done. That is, even if the PIDs assigned to the MPEG2 video data and audio data of each program transmitted in the MPEG2-TS format from each output terminal of the video server 10 are fixedly assigned in advance as shown in FIG. It is not out of the spirit of. In this case, when the system control device 50 distributes a new program, the empty video output terminal of the video server 10 is simply searched and the distribution output terminal is determined. And PID of audio data is assigned. Therefore, the system control device 50 does not need to search or determine the PID as described above, and the processing can be simplified. Further, as the program selection information transmitted from the system controller 50 to the receiving terminals 20, 30, 40, only the receiving terminal ID and the PID of the MPEG video data and audio data of the program to be newly distributed may be transmitted. As shown in FIG.
Since the PIDs of the MPEG video data and audio data of the program to be newly distributed and the output terminals of the video server 10 are preliminarily associated with each other, the receiving terminals 20, 30,
The channel 40 can recognize the channel number to be selected by only knowing the PID of the MPEG video data and audio data transmitted from the system controller 50, and the digital tuner unit 22 can receive a desired program. . Therefore, from the system control device 50 to the receiving terminal 2
Since it is not necessary to transmit the distribution channel information of the program (that is, the channel number or the specific modulation frequency of the channel number) to 0, 30, 40 as the program selection information, the program selection information to be transmitted can be simplified. it can.

Next, an embodiment in which the above-mentioned video / audio information distribution apparatus of the present invention for providing the VOD service can be provided with the digital broadcasting service will be described with reference to FIGS. 3 and 9. FIG. 9 is a system configuration diagram of a video / audio information distribution apparatus of the present invention that can also provide the digital broadcasting service. 9 is almost the same as FIG. 1, and the same portions are denoted by the same reference numerals and detailed description thereof will be omitted. The difference between FIG. 9 and FIG. 1 is that a receiving device (specifically, an antenna) 200 for receiving digital broadcasting is provided.
Is provided, and the received wave is supplied to the receiving terminals 20, 30, 40 via the bidirectional mixing / branching device 65. As described in the above-mentioned related art (FIGS. 11 and 12), a plurality of program data and PSI data (PAT, PMT, N) are displayed on the receiving terminals 20, 30, and 40 for each digital broadcast program.
It is supplied in the MPEG2-TS format which is time division multiplexed.

The receiving terminals 20, 30, 40 have a mode for viewing a program by the VOD service and a mode for viewing a program by the digital broadcasting service. The channel that provides the VOD service and the channel that provides the digital broadcasting service are predetermined. Hereinafter, a program selection procedure when, for example, the receiving terminal 20 receives a digital broadcast will be described.

The digital broadcast program selection procedure in the receiving terminal 20 is basically the same as the procedure shown in FIG. 13, and is transmitted to the receiving terminal 20 in the MPEG2-TS format together with each digital broadcasting program in a time division multiplexed manner. It will be done based on the incoming PSI. Specifically, in the receiving terminal 20 shown in FIG. 3, based on the EPG for the digital broadcasting service displayed from the program guide generation unit 110 via the video display unit 26,
When the viewer inputs the program number of the desired program being digitally broadcast from the operation command input unit 100, the terminal control unit 29 controls the receiving terminal 20 in the control mode for receiving the digital broadcast. The operation of the receiving terminal 20 and the program selection procedure in the control mode for receiving digital broadcasting are shown in FIG.
Since it is the same as the procedure shown in FIG. 3, its description is omitted here. However, in the receiving terminal 20, when the viewer inputs the program number of the desired program that is digitally broadcast from the operation command input unit 100, the terminal control unit 29 assigns the digital tuner unit 22 to the digital broadcast. The digital tuner unit 22 operates so as to select any of the designated channels, and the digital tuner unit 22 operates to select the designated channel. In addition, the receiving terminal 20 is MPEG
The demultiplexing unit 24 demultiplexes the PSI that is time-division multiplexed with each program of digital broadcasting in the 2-TS format, and notifies the terminal control unit 29 of the PSI such as PAT, PMT, and NIT that have been demultiplexed and acquired. Based on this, the terminal control unit 29 executes the program selection process based on the PSI shown in FIG. In the receiving terminal 20, based on the EPG for the VOD service displayed from the program guide generation unit 110 via the video display unit 26, the viewer inputs the program number of the desired program in the VOD service to the operation command input unit. When input from 100, the terminal control unit 29 operates to control the receiving terminal 20 in the control mode for receiving the VOD service.

As described above, in the video / audio information distribution system of the present invention, the control mode of the receiving terminal 20 is added to the control mode for receiving the VOD service as described above, and the control mode for receiving the digital broadcast is provided. By appropriately switching these control modes according to a program request command from the operation command input unit 100 of 20, the viewer can also watch the program transmitted by digital broadcasting.

The embodiments of the video / audio information distribution system of the present invention have been described above. In the video / audio information distribution system of the present invention, as shown in FIG.
Although the multiplexers 12, 13, and 14 are provided in 0, the present invention is not limited to this configuration. That is, FIG.
As shown in FIG. 5, the multiplexing units 12, 13, and 14 are not provided in the video server 10 and are configured as independent devices, and the interface unit 16 (for example, ATM: Asy) is provided in the video server 10.
nchronous Transfer Mode) and the MPEG video data and audio data of each program output from the compressed video / audio data storage unit 11 are supplied to the multiplexing units 12, 13, and 14 via the interface unit 16. good.

[0050]

As described above, according to the video / audio information distribution system of the present invention, the receiving terminals 20, 30,
For 40, the MPEG2 video data and audio data of the requested program are simply added with the designated PID.
The viewer can watch the desired program by sending it in S format and transmitting the program selection information instead of PSI at the same time. Therefore, since the PSI change processing, which requires a huge amount of processing and requires high-speed processing, is not performed at all, the processing amount can be greatly simplified, and even if the program requests from viewers are concentrated in one period, It is possible to provide the VOD service to the viewer very stably. In addition, the receiving terminals 20, 30,
In addition to the MPEG2-TS in which the request program is time-division-multiplexed, the above-mentioned program selection information is sent to 40 in advance, so there is no need to separate and recognize the PSI from the MPEG2-TS when receiving the program. It is possible to greatly simplify the program reception selection processing of 20, 30, and 40. Furthermore, the receiving terminal 2
In addition to the control modes of 0, 30, 40 for receiving the VOD service, a control mode for receiving the digital broadcasting is provided, and the viewer is sent by the VOD service and the digital broadcasting service by appropriately switching these control modes. You can watch any of the coming programs.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a system configuration of a video / audio information distribution system of the present invention.

FIG. 2 is a diagram showing an example of a configuration of a video server in the video / audio information distribution system of the present invention.

FIG. 3 is a diagram showing an example of a configuration of a receiving terminal in the video / audio information distribution system of the present invention.

FIG. 4 is a diagram showing an example of a configuration of a system control device in the video / audio information distribution system of the present invention.

FIG. 5 is a diagram showing a program selection reception flow in the video / audio information distribution system of the present invention.

FIG. 6 is a diagram showing an example of a program selection menu displayed on the receiving terminal of the video / audio information distribution system of the present invention.

FIG. 7 is a diagram showing an example of program distribution management in the system controller of the video / audio information distribution system of the present invention.

FIG. 8 is a diagram showing another example of program distribution management in the system controller of the video / audio information distribution system of the present invention.

FIG. 9 is a diagram showing an example of a system configuration when a digital broadcasting service is provided in the video / audio information distribution system of the present invention.

FIG. 10 is a diagram showing another example of the configuration of the video server in the video / audio information distribution system of the present invention.

FIG. 11 is a diagram schematically illustrating a stream structure of MPEG2-TS.

[Fig. 12] Fig. 12 is a diagram illustrating an example of specific contents of PSI time-division-multiplexed with MPEG2-TS.

FIG. 13 is a diagram showing a program selection reception flow in digital broadcasting.

[Explanation of symbols]

 10 video server 12, 13, 14 multiplexing unit 15 server control unit 20, 30, 40 receiving terminal 24 demultiplexing unit 25 compressed video / audio data decompression unit 29 terminal control unit 50 system control device 53 system control unit 60 bidirectional transmission path 61, 62, 63 Digital modulator 66 Coaxial or optical cable

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yukari Sakuramoto Yukari Sakuramoto, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. multimedia system development headquarters (72) Takashi Takeuchi Yoshida, Totsuka-ku, Yokohama-shi, Kanagawa 292, Machi, Ltd. Hitachi, Ltd., Multimedia System Development Headquarters (72) Inventor, Daiki Tanaka, 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa

Claims (7)

[Claims] 1. A video server for storing compressed video / audio data of each program to be distributed and transmitting the compressed video / audio data of a requested program in response to a program request from a viewer, and modulating with a predetermined channel and a predetermined modulation method. Two-way transmission path for transmitting the compressed video / audio data of the requested program and the program request from the viewer, inputting and transmitting the program request from the viewer, and receiving and expanding the compressed video / audio data of the requested program delivered Receiving terminal for displaying, acceptance of a program request from a viewer, and a system for integrally controlling program distribution by instructing a video server to transmit compressed video / audio data of a requested program from a predetermined output terminal in response to the program request It consists of a control device,
In a video / audio information distribution system for appropriately distributing a requested program to a receiving terminal in response to a program request from a viewer, the video server compresses the video / audio information of each program by a predetermined video / audio compression method. A compressed video / audio data storage unit for storing video / audio data, and program identification information added to the compressed video / audio data of the requested program read from the compressed video / audio data storage unit, and time-division along with the compressed video / audio data of other programs. The receiving terminal includes a multiplexing unit for transmitting a multiplexed stream and a server control unit for controlling the operation of the entire video server such as the compressed video / audio data storage unit and the multiplexing unit. Time-division including compressed video and audio data of the requested program transmitted from the video server on a predetermined channel and with a predetermined modulation method. A program receiving unit for receiving the duplexed stream, a demultiplexing unit for decompressing the compressed video / audio data of the requested program from the time division multiplexed stream containing the compressed video / audio data of the received requested program, and a demultiplexing unit for the separated requested program. A compressed video / audio data decompression unit that decodes the compressed video / audio data and decompresses it into the original video / audio information, and a two-way communication unit that communicates program request commands and program selection information with the system control device. An operation command input unit for inputting an operation command such as a program request according to a user's operation to the receiving terminal, a program receiving unit, a demultiplexing unit, a compressed video / audio data decompression unit, a bidirectional communication unit, an operation command input unit And a terminal control unit for controlling the operation of the entire receiving terminal, the system control device passes the program request command and the program selection information necessary for receiving the requested program to and from the receiving terminal. A server control command or a video server for instructing the video server to transmit the compressed video / audio data of the requested program from the predetermined output terminal with the predetermined program identification information added between the terminal communication section that receives the information and the video server. And a server communication unit that communicates operating information of the server, and a system control unit that comprehensively manages the server operating status and the program request status of the receiving terminal, and controls the operation of the entire system to appropriately distribute the requested program to the receiving terminal. When the system control device receives a program request command from the receiving terminal, the system control device transmits the server control command to the video server based on the server operating status and the program request status of the receiving terminal, and at the same time, to the receiving terminal. The program selection information is transmitted, and the video server is designated from the designated output terminal based on the server control command from the system controller. The compressed video / audio data of the requested program is transmitted in the time-division multiplexed stream by adding the program identification information, and the receiving terminal receives the program selection information from the system control device through the bidirectional transmission path. A video / audio information distribution system, characterized in that, after receiving the time-division multiplexed stream transmitted, the compressed video / audio data of the requested program is separated and expanded and displayed. 2. The video / audio information distribution system according to claim 1, wherein, as the program selection information, channel information for distributing a requested program and the program identification information are transmitted from a system controller to a receiving terminal. 3. The video / audio information distribution system according to claim 1, wherein the program identification information added to the compressed video / audio data of the requested program is uniquely assigned in advance to each output terminal of the video server. . 4. The video / audio information distribution system according to claim 3, wherein the program identification information is transmitted from a system control device to a receiving terminal as the program selection information. 5. The receiver according to claim 1, further comprising a receiving device for receiving a digital broadcast by a stream in which compressed video / audio data of a plurality of programs and the program selection information are time-division multiplexed, and the digital broadcasting received by the receiving device. When the division-multiplexed stream is supplied to the receiving terminal via the bidirectional transmission path and the digital broadcast is received, the demultiplexing unit selects program selection information from the time-division multiplexed stream of the digital broadcast. A video / audio information distribution system characterized by separating compressed video / audio data of a desired program from a plurality of programs broadcast by digital broadcasting based on the program selection information, and decompressing the compressed video / audio data. 6. The terminal control unit of the receiving terminal according to claim 5, having a control mode of receiving a program of the digital broadcast and a control mode of receiving a program stored in the video server, A video / audio information distribution system, wherein the above two control modes are appropriately switched according to a program request operation of a viewer from an operation command input unit of a terminal. 7. The video / audio information distribution system according to claim 1, wherein the multiplexing unit of the video server is connected as an independent device to each output terminal of the video server in cascade connection.