Forward error correction at MPEG-2 transport stream layer

• US 6,556,588 B2
• Filed: 01/04/2002
• Issued: 04/29/2003
• Est. Priority Date: 12/23/1998
• Status: Expired due to Term

• Current Assignee: Cisco Systems Canada Co. (Cisco Systems, Inc.)
• Original Assignee: Cisco Systems Canada Co. (Cisco Systems, Inc.)
• Inventors: Wan, Xiang, Morin, Marc H.
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Levitan, Dmitry
• Application Number:
  US10/041,137
• Publication Number:
  US 20020054608A1
• Time in Patent Office: 480 Days
• Field of Search: 370/473, 370/529, 714/52, 714/57, 714/699, 714/746, 714/752
• US Class Current: 370/474
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/2707 Simple row-column interleaver, i.e. pure block interleaving
• CPC Class Codes: H03M 13/2915 with an error detection code in one dimension
• CPC Class Codes: H03M 13/373 with erasure correction and erasure determination, e.g. for packet loss recovery or setting of erasures for the decoding of Reed-Solomon codes
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4348 Demultiplexing of additional data and video streams
• CPC Class Codes: H04N 21/435 Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream

Abstract

The invention is for a system and method for performing forward error correction on an MPEG-2 transport stream that has optional error correction information embedded within the sport stream. An error correction operation is performed on a super group of packets within the transport stream. The error correction data is inserted into a created trailer group of MPEG-2 compliant transport stream packets having no payload, but only an adaptation field The trailer group packets are optional and therefore can be discarded by a standard MPEG-2 decoder, but can also be used to recover data lost in the transmission of the transport stream. The invention results in a system and method to correct an MPEG-2 transport stream that can be used in any one of the digital video broadcast (DVB) formats, without the need for error correction decoders which are specific to the DVB format.

Claims

1. A system for providing compressed video data, the system comprising:

a processor designed or configured to receive compressed video contained in data packets, and designed or configured to output a data stream comprising a super group including a predefined number of packets and a trailer group including a sufficient number of packets to accommodate error correction data obtained from forward correction of the compressed video data; and

a transmitter designed or configured to transmit the super group and the trailer group, wherein the trailer group includes information identifying each trailer group packet as optional.

2. The system of claim 1 wherein the compressed video data is compressed according to an MPEG standard.

3. The system of claim 1 wherein the trailer group includes index data which relates the error correction data to one or more corresponding super group packets.

4. The system of claim 1 wherein information identifying each trailer group packet as optional is provided to direct asymmetric decoders to ignore the error correction data in the trailer group.

5. The system of claim 1 wherein processor is designed or configured to output the trailer group after the super group.

6. The system of claim 5 wherein the processor is designed or configured to output two super groups followed by two corresponding trailer groups.

7. The system of claim 5 wherein the processor is designed or configured to output the super group followed by a predefined number of null packets before the trailer group.

8. The system of claim 7 wherein the predefined number of null packets is equivalent to an estimated maximum burst error of a broadcast environment.

9. The system of claim 1 wherein the processor is further designed or configured to perform Reed Solomon coding to provide the error correction data.

10. The system of claim 1 wherein the processor is further designed or configured to perform error correction operation on parallel bytes within each packet of the super group.

11. The system of claim 1 the processor is further designed or configured to shift compressed data from the super group to the trailer group.

12. A system for providing compressed video data, the system comprising:

means for processing compressed video data contained in compressed video data packets to output a data stream comprising a super group including a predefined number of data packets and a trailer group including a sufficient number of packets to accommodate error correction data obtained from forward correction of the compressed video data; and

means for transmitting the super group and the trailer group.

13. The system of claim 12 wherein the means for processing compressed video data performs an error correction operation on parallel bytes of each packet within the super group.

14. A system for receiving compressed video data, the system comprising:

a receiver designed or configured to receive a data stream comprising a super group and a trailer group, the super group comprising compressed video data, the trailer group comprising error correction data, indexing information, and a tag identifying each trailer group packet as optional; and

a processor designed or configured to perform an error recovery operation on the compressed video data in the super group using the error correction data and the indexing information contained in the trailer group.

15. The system of claim 14 further comprising a decoder designed or configured to decompress the compressed video data.

16. The system of claim 15 wherein the decoder is designed or configured to decompress the compressed video data without using the comprising error correction data and indexing information.

17. The system of claim 14 wherein the processor is further designed or configured to extract the super group and the trailer group from a data stream received by the receiver.

18. The system of claim 14 the compressed video data is compressed according to an MPEG standard.

19. The system of claim 14 wherein the processor is designed or configured to perform Reed Solomon coding to provide the error recovery.

20. A system for receiving compressed video data, the system comprising:

receiving means for receiving a data stream;

processing means for extracting a super group and a trailer group corresponding to the super group from the received data stream; and

processing means for performing an error recovery operation on compressed video data in the super group using the error correction data in the corresponding trailer group, wherein the trailer group includes a tag identifying each trailer group packet as optional.

21. The system of claim 20 further comprising decoder means for decompressing the compressed video data.

22. The system of claim 21 wherein the decoder means decompresses the compressed video data without using the comprising error correction data and indexing information.