Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/21—Server components or server architectures
  • H04N21/218—Source of audio or video content, e.g. local disk arrays
  • H04N21/21815—Source of audio or video content, e.g. local disk arrays comprising local storage units
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
  • H04N21/234—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
  • H04N21/2343—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
  • H04N21/235—Processing of additional data, e.g. scrambling of additional data or processing content descriptors
  • H04N21/2355—Processing of additional data, e.g. scrambling of additional data or processing content descriptors involving reformatting operations of additional data, e.g. HTML pages
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
  • H04N21/238—Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams
  • H04N21/2387—Stream processing in response to a playback request from an end-user, e.g. for trick-play
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/47—End-user applications
  • H04N21/472—End-user interface for requesting content, additional data or services; End-user interface for interacting with content, e.g. for content reservation or setting reminders, for requesting event notification, for manipulating displayed content
  • H04N21/47202—End-user interface for requesting content, additional data or services; End-user interface for interacting with content, e.g. for content reservation or setting reminders, for requesting event notification, for manipulating displayed content for requesting content on demand, e.g. video on demand
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
  • H04N21/47—End-user applications
  • H04N21/488—Data services, e.g. news ticker
  • H04N21/4884—Data services, e.g. news ticker for displaying subtitles
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
  • H04N21/61—Network physical structure; Signal processing
  • H04N21/6156—Network physical structure; Signal processing specially adapted to the upstream path of the transmission network
  • H04N21/6175—Network physical structure; Signal processing specially adapted to the upstream path of the transmission network involving transmission via Internet
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
  • H04N21/65—Transmission of management data between client and server
  • H04N21/658—Transmission by the client directed to the server
  • H04N21/6587—Control parameters, e.g. trick play commands, viewpoint selection
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/16—Analogue secrecy systems; Analogue subscription systems
  • H04N7/173—Analogue secrecy systems; Analogue subscription systems with two-way working, e.g. subscriber sending a programme selection signal
  • H04N7/17309—Transmission or handling of upstream communications
  • H04N7/17318—Direct or substantially direct transmission and handling of requests

Definitions

• the present invention relates to the provision of multimedia services on demand via telecommunication networks.
• a particular field of application is that of digital television in which a widespread standard is MPEG2.
• Transport Streams (TS) and Program Streams (PS).
• a "program” is defined as a set of elementary streams correlated temporally, that is to say carrying each information to be restored with respect to a common time base.
• a PS stream carries a single program in the form of packets of relatively large and possibly variable length.
• Program (PS) streams are typically used for storing programs on disk.
• Transport Streams (TS) consist of fixed-length packets belonging to one or more programs, and are used for transmission or broadcast over networks.
• These multiplexed streams TS, PS are constructed from packaged elementary stream (PES).
• PES packaged elementary stream
• the raw elementary streams (ES) derived directly from the video or audio coding are first put into PES packets of variable length.
• the PES streams are then segmented to constitute the TS or PS packets to be multiplexed.
• the MPEG2 standard is used in several multimedia content distribution systems, including DVD ("Digital Versatile Disc”) and DVB ("Digital Video Broadcast”).
• the DVD is an optical recording medium disc on which programs are recorded in so-called VOB ("Video Object Block") files that correspond to PS stream packets.
• VOB Video Object Block
• IFO files are also recorded on the disc and contain information on chapters, subtitle tracks and sound tracks. IFO files allow to offer the user navigation and interactivity elements, especially for the choice of languages or subtitles, sometimes for the choice of angles of the camera, for access to the main menu and to intermediate menus, to move forward or backward in program chapters, and so on.
• the DVD also contains so-called BUP files, which are backups of IFO files.
• the multimedia content (VOB), including sound, images and subtitles, is thus dissociated from the tree (IFO) between the different menus.
• the interactivity of the DVD is based on the display of the video sequence. IFO files are used to select portions of video to render according to the actions triggered by the user, usually using its remote control. The succession of different video portions creates interactivity through a navigation tree.
• the DVD player has five 16-bit registers to store any information to act on the tree followed in the IFO file according to the previous choices.
• the video footage of a DVD is encoded according to the MPEG2 standard.
• MPEG2 compression consists in cutting the video sequence into blocks of images called GOP ("Group of Picture") with an approximate duration of twelve images. Added to this is the audio component (s), the possible subtitles and other data, among others for navigation. These different ones form what is called a VOBU ("Video Object Unit"), which is therefore a subset of the video sequence.
• a chapter is a "program” made up of "cells”, themselves consisting of VOBUs.
• a film composed of several chapters is a succession of "programs” also called PGC ("Program Chain”).
• a DVD can be seen as a succession of PGCs with a command structure, encoded in the IFO files, allowing them to be chained or navigated among these PGCs.
• the interactivity offered by a DVD includes the ability to navigate through video sequences. At each end of the cell, a command is inserted allowing the decoder to determine the next action to be executed.
• the interactivity is contained in PES specific to the DVD standard.
• the definition of the buttons presented on the screen is in a special package called PCI ("Presentation Control Information"). This PCI packet is always (whether or not there are buttons to display) in the first sector of each VOBU, that is, in its first 2048 bytes.
• PCI Presentation Control Information
• a PS stream demultiplexer When playing the DVD, a PS stream demultiplexer separates the audio PES, the video PESs and the PES containing the subtitle descriptions, as well as the PCI packets for the interactivity button descriptions.
• An overlay function allows you to display multiple video clips in overlay, including video and subtitles, the bottom of a menu page and buttons, and so on.
• subtitles are saved as images that are overlaid on the video stream by the player.
• the subtitles are in private PS header packets 0x000001 BA that contain PES packets of the 0x000001 BD header.
• a subtitle PES consists of the packet size followed by the data and finally control data consisting of a list of control sequences.
• These control sequences called “subpicture display control sequences" or SP_DCSQ are linked tables of commands where one - AT -
• the flow contains a table that associates with each of these four values a color number in the PGC palette and a contrast level.
• DVB is a standard for broadcasting digital television.
• the streams are broadcast in TS format, which allows to send several programs in a given bandwidth.
• the user thus receives a "bouquet" of strings and tables describing information such as names of the strings, names of the programs in progress, etc. These tables allow the user to locally select the channels to display.
• a TS stream has a simple and generic structure.
• a table is composed of sub-tables, themselves composed of sections. Each section consists of a header and then a list of descriptors or "tags" (unitary pieces of information).
• the stream TS transports MPEG2-compatible audio and video PES packets, and also so-called PSI ("Program Specify Information") tables containing signaling.
• PSI tables include a PAT ("Program Association Table") describing each service physically present on the TS, a PMT (“Program Map Table”) for each service physically present on the TS and finally a CAT ("Conditional Access Table”) for access control.
• NIT Network Information Table
• SDT Service Description Table
• Event Information Table giving information about the current or next events (program name, guest names, start time, duration, etc.) on the multiplex services;
• DVB is used to distribute digital television over telecommunication networks, notably of the ADSL type ("Asymmetric Digital Subscriber One").
• ADSL Asymmetric Digital Subscriber One
• SPTS stream Single Program Transport Stream
• the encryption being performed at the TS level.
• the user's decoder To view content, the user's decoder must receive a TS stream.
• Video On Demand (VOD) services also use the DVB standard.
• the telecommunication network supports the Internet Protocol (IP), and the TS streams are broadcast in point-to-point mode. Once the transmission of the requested program has begun, the user can have playback, pause and fast forward or rewind features. These functionalities correspond to displacements with respect to the current position in the transport stream.
• IP Internet Protocol
• VOD services are currently very limited. In particular, it is not possible to display the buttons of the menus provided on a DVD by associating them with the corresponding actions. DVD-specific PES that contain interactivity elements are not supported by the decoder, which is usually only compatible with DVB.
• VOD offers include, after transmission of the requested program, the sending of a DVD disc to the user. This will then benefit from the interactivity of the DVD, but not at the moment of its first visualization of the program.
• such an offer has the disadvantage of requiring that the content be sent twice to the user, in two different forms.
• the invention provides a method of providing an on-demand multimedia service from multimedia data sources each comprising at least one program stream. According to the invention, the method comprises the following steps:
• the stackable elements include interactive menu buttons described in interactivity data packets extracted from the program stream.
• the data page then preferably contains a representation of the interactive menu buttons and an indication of actions respectively associated with these buttons, obtained in the interactivity data packets extracted from the program stream.
• a new request can be sent to the VOD platform to trigger the action associated with the button in question.
• the method makes it possible to emulate multimedia interaction functions of a first type on a transmission architecture of a second type, not designed to support such functions.
• the multimedia interaction functions of the first type may especially be those offered by a DVD, while the architecture of the second type may be that of DVB.
• the first channel is typically a DVB channel
• the second channel (distinct from the first channel) is an HTTP data channel or the like.
• the transport stream and the packets of superimposable elements are transmitted, respectively, in a first channel and a second channel because they are decorrelated since they are put in different transport formats (transport streams and pages, respectively). data) even if they are transported by the same network (for example an ADSL type network).
• the stackable elements include subtitles.
• the data page then contains at least one subtitle associated with a respective display time index. It can also contain a script to command the automatic sending of a new request following the decoding of the last subtitle represented in the page.
• the subtitles are thus transmitted in data pages without the need to be embedded in the video stream before sending.
• the method advantageously makes it possible to use the content remotely interactive movie (multi-angle, subtitles, chapters, 7), the interactive content of a DVD (bonus, games, making of, trailers, %), all types of existing games on DVD, all types of edutainment content existing on DVD and generally all types of content taking advantage of the interactivity offered by the DVD system.
• Another aspect of the invention relates to a service platform for providing an on-demand multimedia service from multimedia data sources each comprising at least one program stream.
• This platform comprises: means for converting a program stream of at least one source into a transport stream; means for extracting, in the program stream, packets describing elements superimposable on a video component of the transport stream; means for transmitting the transport stream to a user terminal along a first channel via a telecommunication network; means for receiving requests from the user terminal via the telecommunication network; means for converting at least one of the packets describing superimposable elements into at least one data page in response to receiving a request from the user terminal; and means for returning the data page to the user terminal following a second channel via the telecommunications network.
• Still another aspect of the invention relates to a computer program for installation in a service platform for providing an on-demand multimedia service from multimedia data sources each comprising at least one program stream.
• the program includes instructions for controlling the following steps when executing the program by a platform processing unit:
• a transport stream obtained by converting a program stream of at least one source; extracting from the program stream packets describing elements superimposable on a video component of the transport stream;
• the invention also relates to a digital television decoder adapted to the implementation of the method above, and comprising:
• buttons and / or subtitles means for receiving, according to a second channel, data pages comprising representations of interactive menu buttons and / or subtitles and displaying said buttons and / or subtitles in superposition with a video component of the transport stream.
• FIG. 1 is a block diagram of an exemplary VOD service platform according to the invention
• FIG. 2 is a simplified block diagram of an exemplary digital television decoder according to the invention.
• FIG. 3 is a block diagram of another example of a VOD service platform according to the invention.
• a service platform 1 comprises a network interface 2 for communicating with user terminals.
• the used telecommunications network is for example an IP network on ADSL
• the service platform exploits interactive contents available on recording media 3 of the DVD type or the like.
• a preliminary step of the method consists in recording the contents of the DVDs 3 in a database 4 of the platform, stored on hard disks.
• the database 4 stores all the VOB files, which contain PS stream packets, as well as the corresponding Interactivity Information Files (IFO) and their backups (BUP).
• IFO Interactivity Information Files
• BUP Backups
• the platform 1 also comprises a video on demand (VOD) server 5.
• VOD video on demand
• the server 5 is adapted to present to the users, via a web server 8, a graphical interface which enables them to select the requested content and to carry out the corresponding transactions.
• the server 5 manages the VOD sessions of the various users and controls the playback of audio and video files corresponding to the content requested by the users, as well as any subtitle files. In this case, these files are stored in the database 4 in PS format, and the VOD server 5 must therefore be adapted to perform the addressing of the stream in PS format.
• the web server 8 dialogs with the users through the network interface 2, typically in the form of HTML pages ("HyperText Mark-up
• the PS stream which is controlled by the server 5 is submitted to an MPEG2 6 repultiplexer which converts it into a TS single program stream (SPTS) adapted for DVB transmission.
• MPEG2 remultiplexing operation is conventional.
• the PES packets are extracted from the PS stream with the corresponding time markers, and then these are used to multiplex the PES packets into a TS stream.
• the remultiplexer 6 is composed as follows: a PS 6A flux demultiplexer which separates the different PES streams;
• a filter 6B which extracts the PES packets containing the interactivity data as well as some possible PES packets containing subtitles; a TS 6C stream multiplexer which assembles the stream TS from the streams
• PES audio and video read and inserting the MPEG tables necessary for transmission in DVB.
• the TS stream thus constructed is transmitted to the user concerned via the interface 2 and the telecommunications network.
• the PES packets extracted by the filter 6B are submitted to a converter 9 whose role is to convert these packets into HTML pages (flash or other %) which will eventually be transmitted via the server 8 to be displayed at the user.
• FIG 2 shows schematically the DVB decoder 10 which is equipped with a user. Its network interface 1 1 retrieves the received TS stream, and provides it to MPEG2 demultiplexing and decoding module 12. This module 12 renders the audio and video signals that are supplied to the television 20 of the user. In the context of the present invention, the demultiplexing and decoding module 12 may be standard.
• the user interface typically comprises an infrared remote control 21 which, according to the actions of the user, sends different signals picked up by an infrared detector 13 of the decoder 10.
• the decoder 10 comprises a communication software layer 14, generally based on an HTML browser-type application for communicating with the web server 8 of the service platform 1 (a flash-type or other interpreter can also be used alternatively) .
• the browser 14 is informed of certain user control signals sensed by the detector 13. Such signals relate, for example, to pause / read or fast forward / rewind commands, which the browser 14 translates into HTML requests. transmitted via the interface 1 1 and the telecommunications network according to the HTTP protocol ("HyperText Transfer Protocol"). These requests carry interpreted commands at the level of the VOD server 5 to give rise to corresponding modifications of the reading of the multimedia stream in the database 4.
• the user commands that the browser 14 of the decoder 10 echoes in HTML requests transmitted over the network also include interaction commands that are related to the interactivity information encountered in the DVDs.
• commands such as chapter changes or commands that can be selected from DVD menus displayed on the screen result in the delivery of specific HTML requests that will be interpreted by a module.
• the interpreter module 7 analyzes the interaction commands received in the HTML requests in relation to the IFO file, stored in the database 4, which corresponds to the video sequence being transmitted.
• the IFO 7 interpreter is similar to the one commonly found in DVD players. For each current DVD session for a user, he notably allocates a memory area to emulate the five 16-bit registers storing the information that makes it possible to act on the tree followed in the IFO file according to the previous choices.
• each command of the user can be interpreted to control the addressing of the stream being played according to the chapter of the DVD, to select audio or subtitle files corresponding to languages chosen by the user, to select portions of video corresponding to camera angles chosen by the user, for selecting PES associated with the display of a menu, etc.
• the VOD server 5 controls the reading in memory of the stream PS to be supplied to the remultiplexer 6.
• HTTP is a protocol based on a request-response schema.
• a client that sends a request to a server waiting for a response that tells him if his request has been taken into account, processed successfully, being processed etc.
• the platform of VOD 1 does not does not immediately return a response to the request sent by the browser 14 of the decoder, or else a provisional response indicating that the request is being processed by the server.
• the request is timed to allow the platform time to perform the required processing.
• the interpreter 7 determines the position on which the VOD server 5 must be positioned. A command is sent to the VOD server giving the subscriber the broadcast program the position from which the broadcast is resumed. From this new position, the stream in PS (DVD) format is sent to the demultiplexer 6. This generates on the one hand a stream in TS (DVB) format suitable for broadcasting on IP audiovisual program. Meanwhile, the interactivity data extracted by the filter 6B are retrieved by the converter 9, as well as any subtitle files.
• the interpreter 7 commands the converter 9 to generate an HTML page, including the description of the buttons and their associated actions.
• This page is provided to the web server 8 which then generates the response to the decoder request with the web page in the body of the response.
• This message is sent in the data channel and not in the DVB stream.
• the browser 14 of the decoder 10 interprets the returned page and displays its contents, including the associated images, in superposition of the video stream received on the DVB channel (overlay module 15 of FIG. 2).
• the following actions of the user using his remote control 21 will then be analyzed by the browser 14 in connection with the actions associated with the buttons to trigger, if necessary, new HTTP requests to the platform.
• a similar method is used to display the subtitles possibly selected by the user.
• a subtitle selection menu is displayed as described above.
• the browser 14 sends to the platform 1 an HTTP request that the interpreter 7 analyzes to recover the selected language.
• the subtitle identifier (SID) corresponding to this language is included in a command sent to the filter 6B of the remultiplexer 6 so that the latter extracts the PS stream read under the control of the VOD server 5, the PES packets corresponding to the subscribers. titles to display. These packets are provided to the converter 9 so that it builds HTML pages on the fly. Each page thus generated contains a certain number of sub-images of subtitles to be displayed during the video sequence, these sub-images having been decoded by the converter 9.
• the subtitles contained in the same page are each associated with an index respective temporal data included in the page (in the HTML standard, such an index makes it possible to display only part of a page at the pointed instant).
• This index corresponds to the waiting time indicated in the SP_DCSQ so that the subtitle is displayed at the desired moment.
• the HTML browser 14 of the decoder 10 retrieves the sub-images and displays them in overlay (overlay module 15) at the times indicated on the page.
• the converter 9 When it arrives at the last sequence included in an HTML page, the converter 9 inserts a script into the page (for example javascript). This script is interpreted locally by the browser 14 to generate a new HTTP request to the web server 8, requesting the next page with the following subtitles to display. This makes it possible to have simple management at the server applying the filtering of the PES, avoiding having to keep a context for each of the subscribers using the captioning functionality.
• a script for example javascript
• FIG. 3 illustrates another possible architecture of the VOD service platform according to the invention.
• this platform 30 the remultiplexing of the stream PS, read on a DVD 3, into a stream TS is performed not in real time during a VOD session, but in the preliminary phase of recording the content of the disc 3. There is therefore a lower speed constraint on the MPEG2 remultiplexer 31.
• the multimedia streams are thus recorded in the format TS in the database 32 of the platform 30.
• the addressing of the stream used in the IFO files of the DVD must be modified to take account of the reordering of the stream. This modification is performed by an adaptation module 33 in parallel with the remultiplexing operation.
• the adapted IFO files are stored in the database 32 in relation to the corresponding sequences of the stream TS.
• the IFO interpreter 34 of the platform 30 then exploits the adapted IFO files in order to address to the VOD server 35 the addressing parameters of the stored stream TS.
• the VOD server 35 may be of a conventional type for controlling the reading in TS stream memory.
• the filter of the remultiplexer 31 extracts from the PS stream the PES packets containing the interactivity data as well as those containing subtitles so that they are recorded in the database 32 in relation with the corresponding sequences of the stream TS.
• Each subtitle PES is registered in association with its SID.
• the IFO interpreter 34 controls the reading of the PES files associated with the SID recovered in the HTTP request from the decoder so that they are supplied to the converter 9. The same operation applies for the construction of menu button pages.
• FIG. 3 has the advantages of making it possible to use a VOD server on the market and to avoid the real time remultiplexing operation, which is relatively expensive in computing capacity.
• the invention may be implemented by means of computer programs executed by one or more processors of the service platform 1, 30 and designed to complete the functionalities of the VOD server 5, 35.
• the invention has been described above in the context of DVD and DVB standards. Naturally, it is not limited to these standards. The invention is particularly applicable to all types of interactive content recording media (HD-DVD, BIu Ray, ).
• the user equipment can have very different shapes.
• the decoder 10 can be part of a microcomputer whose screen and sound card are used for the reproduction of the multimedia content and whose user interface (keyboard, mouse, etc.) is used to enter the commands of interaction.

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• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Databases & Information Systems (AREA)
• Human Computer Interaction (AREA)
• Television Signal Processing For Recording (AREA)
• Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)

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• 2007
  • 2007-02-23 WO PCT/FR2007/050846 patent/WO2007099256A1/fr not_active Ceased
  • 2007-02-23 US US12/224,741 patent/US20090044236A1/en not_active Abandoned
  • 2007-02-23 EP EP07731664A patent/EP1994751A1/de not_active Withdrawn

Non-Patent Citations (1)

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