WO2003048974A1 - Procede et dispositif utilises dans un systeme de communication - Google Patents

Procede et dispositif utilises dans un systeme de communication Download PDF

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Publication number
WO2003048974A1
WO2003048974A1 PCT/SE2002/002174 SE0202174W WO03048974A1 WO 2003048974 A1 WO2003048974 A1 WO 2003048974A1 SE 0202174 W SE0202174 W SE 0202174W WO 03048974 A1 WO03048974 A1 WO 03048974A1
Authority
WO
WIPO (PCT)
Prior art keywords
media stream
client
information
server
random access
Prior art date
Application number
PCT/SE2002/002174
Other languages
English (en)
Inventor
Björn ELENFORS
Anders Svensson
Mikael Dahlgren
Johan GÖRSJÖ
Original Assignee
Elenfors Bjoern
Anders Svensson
Mikael Dahlgren
Goersjoe Johan
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Elenfors Bjoern, Anders Svensson, Mikael Dahlgren, Goersjoe Johan filed Critical Elenfors Bjoern
Priority to AU2002365744A priority Critical patent/AU2002365744A1/en
Publication of WO2003048974A1 publication Critical patent/WO2003048974A1/fr

Links

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
    • H04N21/23—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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/60—Network streaming of media packets
    • H04L65/70—Media network packetisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/60—Network streaming of media packets
    • H04L65/75—Media network packet handling
    • H04L65/762—Media network packet handling at the source 
    • 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
    • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/432—Content retrieval operation from a local storage medium, e.g. hard-disk
    • H04N21/4325—Content retrieval operation from a local storage medium, e.g. hard-disk by playing back content from the storage medium
    • 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
    • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/435—Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
    • 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]
    • H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
    • H04N21/83—Generation or processing of protective or descriptive data associated with content; Content structuring
    • H04N21/845—Structuring of content, e.g. decomposing content into time segments
    • H04N21/8455—Structuring of content, e.g. decomposing content into time segments involving pointers to the content, e.g. pointers to the I-frames of the video stream

Definitions

  • the present invention relates to a method according to the pre-characterising clause of claim 1.
  • the invention also relates to an arrangement according to the pre-characterising clause of claim 5.
  • the first method may be defined as "pull”, that is to say the receiver, for example a client, controls the transfer of information.
  • the second method may be defined as "push”, that is to say the transmitter, for example a server, controls the transfer of information or puts out data to the client.
  • the first method is used, for example, by a web server, a client explicitly retrieving the media stream that the client wants and downloading this.
  • the client can begin to decode this concurrently as the stream is being downloaded.
  • the second method is used by a conventional video server.
  • a client wishes to have a media stream sent to him, the video server beginning to send the media stream at the same rate at which it assumes playback is to take place.
  • the client stores the stream in an input buffer and then begins to play it back.
  • a media stream for example a video stream, comprises a limited number of sequences between which it is possible to intervene and begin to decode the stream, so-called random access sequences. It is not possible to decode the stream correctly if the decoding commences midway through such a sequence, since important information will then be missing.
  • MPEG-2 Moving Picture Expert Group
  • RTSP Real Time Streaming Protocol
  • the server at all times knows where the client is in the stream and can therefore respond in order to send the correct information from the media stream at the correct rate to the client.
  • a client may wish to start transferring the media stream at a given point, for example a number of seconds into the stream.
  • the server will then begin to search directly for the nearest legal random access point and commence the transfer from there.
  • the client is simple but the server is all the more complicated. Since the server is responsible for sending data at precisely the right rate to all its clients, this makes it very resource-hungry and errors easily occur.
  • the client retrieves the stream. This means that server and client do not have such a strong link with one another as in the second method.
  • the client itself is responsible for the transfer, that is to say for reading data at the required rate. This gives a reduced risk of error, especially so-called “single point of failure" and improved scalability.
  • a major disadvantage to a "pull"-based solution is that it normally only affords the facility for reading the media stream from beginning to end. It is not possible for a client to effectively find the random access points, which is of interest, for example, in being able to spool rapidly in the media stream. The reason is that, for the client, there is no known relationship, for example, between "playback time" in the media stream and the binary position therein.
  • the client In order to allow a client to move to a given random access point, the client must search in the media stream in order to find this. This can be done, for example, by guessing how far forwards the point lies, reading a partial quantity of the media stream around the estimated point, and decoding this information in order to find the point. If the point did not occur in the partial quantity read, the procedure must be repeated. Since the network is a limited resource with regard to the transmission speed, such a procedure is more expensive and slower than necessary.
  • the object of the present invention is partly to provide an improved method according to the pre-characterising clause of claim 1, and partly to provide an improved arrangement according to the pre-characterising clause of claim 5. This is achieved by the method according to the invention having the characteristic features specified in the characterising part of claim 1. The characteristic features of the arrangement according to the invention are set forth by the characterising part of claim 5.
  • Fig. 1 shows a block diagram of a communications system according to the invention.
  • Fig. 2 shows a generalised media stream comprising a number of sequences which are legal random access objectives.
  • the communications system in Fig. 1 comprises a user side 10, consisting of at least one client 4 which reads a media stream 12 (shown in Fig. 2) with the object of storing it or playing it back, an operator side 9 comprising at least one server 2, which makes one or more stored media streams 8 accessible for transfer to clients 4, and a network situated between the user side 10 and the operator side 9.
  • each client 4 comprises a communications client 5, a decoder 6 and a display unit 7.
  • the function of the communications client 5 is to request the stored media stream 8 and an index file 11 (described in more detail below) from the server 2, and to perform the necessary preliminary decoding before relaying suitable packets of the media stream 12 to the decoder 6.
  • the decoder 6 decodes the media stream 12 and allows the display unit 7 to display it for the user.
  • the client may be constructed in some way other than that shown in the preferred embodiment.
  • the operator side 9 comprises the server 2 and a data store 1 containing the stored media streams 8 and the index files 11.
  • the server 2 sends the stored media streams 8 and the index files 11 over the network 3 to the communications client 5 according to a Hyper Text Transfer Protocol (http).
  • the network 5 may be any type of network familiar to the person skilled in the art, for example the Internet, and this will not be discussed further here.
  • the http protocol enables the communications client 5 to read the sequences 14 of the media stream 12 in random order. In this description and in the figures a distinction is made between the stored media stream 8 and the transferred media stream 12; depending on coding etc. these streams need not be exactly identical.
  • a media stream 12 comprises a limited number of sub-sequences 14, shown in Fig. 2.
  • a media stream is stored in the server 2, it is analysed and the points 13 which are legal random access sub-sequences 14 are saved to the index file 11.
  • the file 11 describes the stream from a random access perspective, that is to say what legal random access sub-sequences 14 it contains.
  • the binary starting point 13 and time in the media stream of each such sub-sequence are stored to the index file 11.
  • the client 4 When the client 4 wishes to use random access it retrieves the index file 11 from the server 2.
  • the client 4 By having access to this index file 11 the client 4 will know where all random access points 13 are located at any juncture during the playback, and can then effectively read such random access sub-sequences 14 if so required. This is done, for example, when spooling rapidly forwards and backwards in media files such as MPEG films where the media stream is a video stream.
  • the client uses this index information in order to come directly to a legal sub-sequence, which in the preferred embodiment of the invention can be sent to the decoder without searching through the stream and requesting too much information from the server.

Abstract

La présente invention concerne un procédé et un dispositif de transfert d'un flux de médias (12) d'un serveur (2) vers un client (4) couplé au serveur (2) sur un réseau (3). Dans ce procédé, le flux de médias (12) est divisé en séquences (14) d'une longueur inconnue. Ce flux de médias (12) est analysé, chacune des séquences (14) étant marquée pour un accès sélectif légal. Des informations relatives à la manière dont est divisé le flux de médias (12) sont recherchées, lesquelles informations sont utilisées pour le transfert de ce flux de médias (12) afin de localiser les séquences (14) à accès sélectif légal.
PCT/SE2002/002174 2001-12-06 2002-11-27 Procede et dispositif utilises dans un systeme de communication WO2003048974A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002365744A AU2002365744A1 (en) 2001-12-06 2002-11-27 Method and arrangement in a communication system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0104114A SE520246C2 (sv) 2001-12-06 2001-12-06 Metod och anordning i ett kommunikationssystem
SE0104114-4 2001-12-06

Publications (1)

Publication Number Publication Date
WO2003048974A1 true WO2003048974A1 (fr) 2003-06-12

Family

ID=20286233

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2002/002174 WO2003048974A1 (fr) 2001-12-06 2002-11-27 Procede et dispositif utilises dans un systeme de communication

Country Status (3)

Country Link
AU (1) AU2002365744A1 (fr)
SE (1) SE520246C2 (fr)
WO (1) WO2003048974A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2323390A2 (fr) * 2008-09-04 2011-05-18 Sk Telecom Co., LTD Système et procédé de transmission multimédia

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996017313A1 (fr) * 1994-11-18 1996-06-06 Oracle Corporation Procede et appareil d'indexation de flux d'informations multimedia
US6101547A (en) * 1998-07-14 2000-08-08 Panasonic Technologies, Inc. Inexpensive, scalable and open-architecture media server
US6167083A (en) * 1997-04-04 2000-12-26 Avid Technology, Inc. Computer system and process for capture editing and playback of motion video compressed using interframe and intraframe techniques
WO2001041000A1 (fr) * 1999-11-30 2001-06-07 New Media Technology, Corp. Systeme et procede pour l'enregistrement chronologique automatique et manuel assiste par ordinateur de supports temporels
US6282549B1 (en) * 1996-05-24 2001-08-28 Magnifi, Inc. Indexing of media content on a network
EP1193920A2 (fr) * 2000-09-29 2002-04-03 Microsoft Corporation Procedé et dispositif pour une meilleure transmission des signaux en continu

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996017313A1 (fr) * 1994-11-18 1996-06-06 Oracle Corporation Procede et appareil d'indexation de flux d'informations multimedia
US6282549B1 (en) * 1996-05-24 2001-08-28 Magnifi, Inc. Indexing of media content on a network
US6167083A (en) * 1997-04-04 2000-12-26 Avid Technology, Inc. Computer system and process for capture editing and playback of motion video compressed using interframe and intraframe techniques
US6101547A (en) * 1998-07-14 2000-08-08 Panasonic Technologies, Inc. Inexpensive, scalable and open-architecture media server
WO2001041000A1 (fr) * 1999-11-30 2001-06-07 New Media Technology, Corp. Systeme et procede pour l'enregistrement chronologique automatique et manuel assiste par ordinateur de supports temporels
EP1193920A2 (fr) * 2000-09-29 2002-04-03 Microsoft Corporation Procedé et dispositif pour une meilleure transmission des signaux en continu

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2323390A2 (fr) * 2008-09-04 2011-05-18 Sk Telecom Co., LTD Système et procédé de transmission multimédia
CN102144390A (zh) * 2008-09-04 2011-08-03 Sk电信有限公司 媒体发送系统和方法
EP2323390A4 (fr) * 2008-09-04 2012-03-21 Sk Telecom Co Ltd Système et procédé de transmission multimédia
US8549164B2 (en) 2008-09-04 2013-10-01 Sk Planet Co., Ltd. Media transmission system and method
EP3169066A1 (fr) * 2008-09-04 2017-05-17 SK Planet Co., Ltd. Systèmes et procédés de transmission de multimédia
EP3169065A1 (fr) * 2008-09-04 2017-05-17 SK Planet Co., Ltd. Systèmes et procédés de transmission de média

Also Published As

Publication number Publication date
SE0104114L (sv) 2003-06-07
SE520246C2 (sv) 2003-06-17
AU2002365744A1 (en) 2003-06-17
SE0104114D0 (sv) 2001-12-06

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