GB2375275A - Insertion of an additional flag with high auto correlation after HDLC flag in H.223 multiplex to improve detection and hence error resilience - Google Patents
Insertion of an additional flag with high auto correlation after HDLC flag in H.223 multiplex to improve detection and hence error resilience Download PDFInfo
- Publication number
- GB2375275A GB2375275A GB0213559A GB0213559A GB2375275A GB 2375275 A GB2375275 A GB 2375275A GB 0213559 A GB0213559 A GB 0213559A GB 0213559 A GB0213559 A GB 0213559A GB 2375275 A GB2375275 A GB 2375275A
- Authority
- GB
- United Kingdom
- Prior art keywords
- flag
- frame
- multiplexing
- mux
- pdu
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/24—Systems for the transmission of television signals using pulse code modulation
- H04N7/52—Systems for transmission of a pulse code modulated video signal with one or more other pulse code modulated signals, e.g. an audio signal or a synchronizing signal
-
- 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
- H04N21/236—Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary 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]
- H04N21/20—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
- H04N21/2381—Adapting the multiplex stream to a specific network, e.g. an Internet Protocol [IP] network
-
- 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
- H04N21/63—Control signaling related to video distribution between client, server and network components; Network processes for video distribution between server and clients or between remote clients, e.g. transmitting basic layer and enhancement layers over different transmission paths, setting up a peer-to-peer communication via Internet between remote STB's; Communication protocols; Addressing
- H04N21/643—Communication protocols
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/04—Speed or phase control by synchronisation signals
- H04L7/041—Speed or phase control by synchronisation signals using special codes as synchronising signal
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Detection And Prevention Of Errors In Transmission (AREA)
Abstract
A multiplexing method for multimedia communication is provided, which is compatible with the H.223 protocol by changing a header of a multiplex protocol data unit (MUX-PDU). The multiplexing method includes the steps of encoding media data, and multiplexing the media data encoded in the step (a) in units of a predetermined frame, and inserting a second flag having a predetermined length with an auto-correlation in the frame after a first flag having the opening and closing of the frame. Therefore, the probability of detecting the MUX-PDU by a receiver is increased by adding a flag having a high auto-correlation to the H.223 MUX-PDU frame, thereby increasing error-resiliency.
Description
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Multimedia Multiplexing Method Technical Field
The present invention relates to a multiplexing method for multimedia communication, and more particularly, to a multiplexing method compatible with the H. 223 protocol by changing a header of a multiplex-protocol data unit (MUXPDU).
Background Art
In general, the H. 324 recommendation prescribes a multiplexing of video and audio signals which is effective in an error-prone channel such as a wireless channel, and includes H. 223 multiplexing, H. 245 controlling, H. 263 video CODEC and G. 723.1 audio CODEC. Also, H. 223 multiplexing is recommended as a method for multiplexing video, audio and other data in protocol data units (PDU) in order to realize a video telephone and video conferencing in a total digital telecommunication network by the ITU-T (the telecommunication standardization sector of the International Telecommunication Union). Also, the H. 324 recommendation includes Mode 1 having high complexity and Mode 3 without having complexity.
According to the Mode 1, while generating a variable length packet an unequal error protection (UEP) is performed by adopting a rate compatible punctured convolutional (RCPC) encoder/decoder (CODEC) in an adaptation layer which is an upper layer. Also, an automatic request for retransmission (ARQ) is used to maintain the overall quality of service (QOS) even though the channel throughput decreases. However, the Mode 1 has
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a high complexity at a portion of RCPC CODEC, which increases the complexity of the overall system. Thus, it is difficult to implement a real-time process. Also, the total channel throughput of the system may decrease rapidly since it adopts a retransmission method. For example, the channel throughput is 50% or less when the retransmission is performed one time" and 33% or less when the retransmission is performed twice. Thus, it is difficult in Mode 1 of the H. 324 to implement transcoding having compatibility with the conventional H. 223. Meanwhile, Mode 3 has virtually no error-protection concept, so that error-resiliency in an error-prone channel is very low.
Disclosure of the Invention
It is an object of the present invention to provide a multiplexing method for multimedia communication, enabling transcoding with the H. 223 protocol by adding a flag which is similar to a pseudo noise code (PN CODE) after a highlevel data link control (HDLC) flag in the multiplexprotocol data unit (MUX-PDU) by the H. 223 protocol.
To achieve the object, there is provided a multiplexing method suitable for multi media communication in the H. 223 protocol, the method comprising the steps of: (a) encoding media data; and (b) multiplexing the media data encoded in the step (a) in units of a predetermined frame, and adding an 8-bit pseudo noise code to an 8-bit synchronisation code representing opening or closing of the frame.
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Brief Description of the Drawings
Figure 1 is a schematic block diagram of a device for implementing a multiplexing method for multimedia communication, compatible with the H. 223 protocol, according to the present invention;
Figure 2A is a diagram showing the structure of a general H. 223 MUX-PDU frame; and
Figure 2B is a diagram showing the structure of an H. 223 MUX-PDU frame according to the present invention;
Figure 3A is a diagram showing the structure of the H. 223 MUX-PDU frame in a filing mode; and
Figure 3B is a diagram showing the structure of the H. 223 MUX-PDU frame in an abort message mode.
Best Mode for Carrying out the Invention
In Figure 1 showing a device for implementing an H. 223 multiplexing method for multimedia communication according to the present invention, a multiplexing portion 130 includes an H. 223 protocol unit 110 and a transcoder 120.
The H. 223 protocol unit 110 and the transcoder 120 performs multiplexing with respect to encoded media data (video, audio and other data), passing through protocol data units (not shown) to transmit to a channel.
Figure 2 is a diagram showing the structure of a general H. 223 MUX-PDU frame.
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As shown in Figure 2A, the H. 223 MUX-PDU is constituted by units of a frame, and the frame includes a high-level data link control (HDLC) flag 110 for transmission control, a header 120 including data information, and a payload 130 including video and audio data.
t All MUX-PDU of the H. 223 are defined using the HDLC flag 110 of Figure 2A. The HDLC flag 110 has a unique bit pattern "01111110" having six continuous"Is"representing the opening or closing of the frame, and is used for synchronization of the frame.
Figure 2B is a diagram showing the structure of an H. 223 MUX-PDU frame according to the present invention.
The MUX-PDU frame includes an HDLC flag 140, an extra flag 150, a header 160 and a payload 170. The transcoder 120 inserts an 8-bit extra flag 150 which is similar to a pseudo noise code (PN CODE) having a high auto-correlation next to the HDLC flag 150 as shown in Figure 2B. Here, the reason for selecting the extra flag having a bit pattern of"10110010"is due to its high auto-correlation as the PN code does. Thus, only the bit pattern of "10110010"may be added as the extra flag 150, or other bit streams having a high auto-correlation may be used thereas to increase error-resiliency. Also, a longer flag may be added in consideration of a trade-off with a channel band width. Preferably, adding the extra flag, suggested by the present invention is used, is prevented in a filling mode in which HDLC flags exist continuously as shown in Figure 3A or an abort message mode without having a payload as shown in Figure 3B.
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The multiplexing method for multimedia communication according to the present invention is not limited to he particular form illustrated and further modifications and alterations will occur to those skilled in the art. That is, interleaving and RCPC processes may be performed by
using each extra flag of a plurality of MUX-PDUs. t Industrial Applicability
As described above, in the multiplexing method for multimedia communication according to the present invention, MUX-PDU including an extra flag having a high auto-correlation is transmitted in the H. 223 protocol, increasing the probability of detecting the MUX-PDU by a receiver. Thus, error-resiliency is also increased.
Also, when the multiplexing method is used together with the RCPC and interleaving methods, error-resiliency can be further increased.
Claims (4)
- Claims 1. A multiplexing method suitable for multi media communication in the H. 223 protocol, the method comprising the steps of: (a) encoding media data; and (b) multiplexing the media data encoded in the step (a) in units of a predetermined frame, and adding an 8-bit pseudo noise code to an 8-bit synchronisation code representing opening or closing of the frame.
- 2. The multiplexing method of claim 1, wherein the frame further comprises: a header having data information: and a payload having video and audio data.
- 3. The multiplexing method of claim 1, wherein the pseudo noise code is a flag having a bit pattern of"10110010".
- 4. The multiplexing method of claim 1, wherein the multiplexing of the step (b) is performed together with an interleaving.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/884,630 US6529528B1 (en) | 1997-06-27 | 1997-06-27 | Multimedia multiplexing method |
| GB9930303A GB2341775B (en) | 1997-06-27 | 1998-05-22 | Multimedia multiplexing method |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0213559D0 GB0213559D0 (en) | 2002-07-24 |
| GB2375275A true GB2375275A (en) | 2002-11-06 |
| GB2375275A9 GB2375275A9 (en) | 2002-11-06 |
Family
ID=26316140
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0213559A Withdrawn GB2375275A (en) | 1997-06-27 | 1998-05-22 | Insertion of an additional flag with high auto correlation after HDLC flag in H.223 multiplex to improve detection and hence error resilience |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2375275A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4435826A (en) * | 1980-09-05 | 1984-03-06 | Hitachi, Ltd. | Frame synchronizer |
| JPH0795189A (en) * | 1993-09-24 | 1995-04-07 | Uniden Corp | Frame synchronization system for digital communication |
| WO1995026081A1 (en) * | 1994-03-18 | 1995-09-28 | Glenayre Electronics, Inc. | High performance modem using pilote symbols for equalization and frame synchronization |
| WO1997038507A1 (en) * | 1996-04-04 | 1997-10-16 | Globespan Technologies, Inc. | A transmission system for digital audio broadcasting |
| US6266349B1 (en) * | 1997-09-08 | 2001-07-24 | Oki Electric Industry, Co., Ltd. | Method and apparatus for detecting frame in data stream |
-
1998
- 1998-05-22 GB GB0213559A patent/GB2375275A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4435826A (en) * | 1980-09-05 | 1984-03-06 | Hitachi, Ltd. | Frame synchronizer |
| JPH0795189A (en) * | 1993-09-24 | 1995-04-07 | Uniden Corp | Frame synchronization system for digital communication |
| WO1995026081A1 (en) * | 1994-03-18 | 1995-09-28 | Glenayre Electronics, Inc. | High performance modem using pilote symbols for equalization and frame synchronization |
| WO1997038507A1 (en) * | 1996-04-04 | 1997-10-16 | Globespan Technologies, Inc. | A transmission system for digital audio broadcasting |
| US6266349B1 (en) * | 1997-09-08 | 2001-07-24 | Oki Electric Industry, Co., Ltd. | Method and apparatus for detecting frame in data stream |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0213559D0 (en) | 2002-07-24 |
| GB2375275A9 (en) | 2002-11-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |