DYNAMIC INTRA-CODED MACROBLOCK REFRESH INTERVAL FOR VIDEO ERROR CONCEALMENT

• US 20060056519A1
• Filed: 12/23/2002
• Published: 03/16/2006
• Est. Priority Date: 12/21/2001
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Polycom Incorporated (Plantronics, Inc.)
• Inventors: Flott, Rick, Horowitz, Michael
• Granted Patent: US 7,020,203 B1
• Time in Patent Office: Days
• US Class Current: 375/240.270
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/166 concerning the amount of transmission errors, e.g. bit error rate [BER]
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/65 using error resilience
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 19/895 in combination with error concealment

Abstract

The present invention provides, in one embodiment, a system and method for concealing video errors. The system includes a coding engine for processing each frame of a video signal to generate macroblocks, selecting a refresh interval based upon network communication parameters, and encoding one or more of the macroblocks as refresh intra-coded macroblocks based upon the selected refresh interval. The refresh intra-coded macroblocks are placed into discrete data packets for transmission across a network to one or more remote devices. Upon receiving other refresh intra-coded macroblocks from a remote device via the network, the coding engine decodes the received intra-coded macroblocks, and places the decoded macroblocks in a newly decoded video frame to be used as reference frame macroblocks for reducing video errors associated with prediction drift.

Claims

1. A method for video error concealment of a video signal, comprising the steps of:

receiving a plurality of macroblocks, each frame of the video signal having an integer number of macroblocks;

selecting a refresh interval based upon network call rates and packet-loss error rates; and

encoding a subset of the plurality of macroblocks as refresh intra-coded macroblocks based upon the selected refresh interval;

wherein the selected refresh interval is an integer m, the integer m and factors of the integer m when divided into the integer number of macroblocks per frame do not give integer quotients.

2. The method of claim 1, wherein for a given packet-loss error rate, the refresh interval decreases as a network call rate increases.

3. The method of claim 1, wherein for a given network call rate, the refresh interval decreases as a packet-loss error rate increases.

5. The method of claim 1, wherein the step of encoding a subset of the plurality of macroblocks further comprises intra-coding every mth macroblock as a refresh intra-coded macroblock.

6. The method of claim 1, wherein the selected refresh interval is equal to a number of video signal frames such that each macroblock associated with a spatial position within the video signal frames is encoded as a refresh intra-coded macroblock at least once.

7. The method of claim 1, further comprising the step of encoding macroblocks not in the subset of the plurality of macroblocks as inter-coded and intra-coded macroblocks.

8. The method of claim 7, further comprising the step of placing encoded macroblocks into discrete data packets for transmission across a packet-switched network.

9. The method of claim 7, further comprising the step of placing encoded macroblocks into a particular format for transport on a circuit-switched network.

10. The method of claim 1, further comprising the steps of decoding encoded macroblocks received from a remote device via a network and detecting missing macroblocks.

11. The method of claim 1, further comprising the steps of decoding the refresh intra-coded macroblocks received from a remote device via a network, and placing the decoded macroblocks in a newly decoded video frame for concealing effects of video error.

4. (canceled)

12. An electronic-readable medium having embodied thereon a program, the program being executable by a machine to perform method steps for video error concealment of a video signal, the method steps comprising:

receiving a plurality of macroblocks, each frame of the video signal having an integer number of macroblocks;

selecting a refresh interval based upon network call rates and packet-loss error rates; and

encoding a subset of the plurality of macroblocks as refresh intra-coded macroblocks based upon the selected refresh interval,

wherein the selected refresh interval is an integer m, the integer m and factors of the integer m when divided into the integer number of macroblocks per frame do not give integer quotients.

14. The electronic-readable medium of claim 12, wherein the step of encoding a subset of the plurality of macroblocks further comprises intra-coding every mth macroblock as a refresh intra-coded macroblock.

15. The electronic-readable medium of claim 12, wherein the selected refresh interval is equal to a number of video signal frames such that each macroblock associated with a spatial position within the video signal frames is encoded as a refresh intra-coded macroblock at least once.

16. The electronic-readable medium of claim 12, further comprising the step of encoding macroblocks not in the subset of the plurality of macroblocks as inter-coded and intra-coded macroblocks.

17. The electronic-readable medium of claim 16, further comprising the step of placing encoded macroblocks into discrete data packets for transmission across a packet-switched network.

18. The electronic-readable medium of claim 16, further comprising the step of placing encoded macroblocks into a particular format for transport on a circuit-switched network.

19. The electronic-readable medium of claim 12, further comprising the steps of decoding encoded macroblocks received from a remote device via a network and detecting missing macroblocks.

20. The electronic-readable medium of claim 12, further comprising the steps of decoding the refresh intra-coded macroblocks received from a remote device via a network, and placing the decoded macroblocks in a newly decoded video frame for concealing effects of video error.

13. (canceled)

21. A system for video error concealment, comprising:

a coding engine configured to

process each frame of a video signal to generate macroblocks, each frame having an integer number of macroblocks dependent upon a video signal format,

select a refresh interval based upon network communication parameters, wherein the selected refresh interval is an integer m, the integer m and factors of the integer m when divided into the integer number of macroblocks per frame do not give integer quotients, and

encode a subset of macroblocks from the generated macroblocks as refresh intra-coded macroblocks based upon the selected refresh interval; and

a macroblock packetization engine configured to place each of the encoded macroblocks into discrete data packets for transmission across a network.

22. The system of claim 21, wherein the network communication parameter is a network call rate.

23. The system of claim 21, wherein the network communication parameter is a packet-loss error rate.

25. The system of claim 21, wherein the coding engine encodes the subset of macroblocks by intra-coding every mth macroblock of the generated macroblocks as a refresh intra-coded macroblock.

26. The system of claim 21, wherein the packetization engine is a transport engine for placing each of the encoded macroblocks into a particular format for transport on a circuit-switched network.

27. The system of claim 21, wherein the coding engine is further configured to decode encoded macroblocks received from a remote device via the network and detects missing macroblocks.

28. The system of claim 21, wherein the coding engine is further configured to decode the refresh intra-coded macroblocks received from a remote device via the network, and place the decoded macroblocks in a newly decoded video frame for concealing effects of video error.

24. (canceled)

29. A system for video error concealment of a video signal, comprising:

means for receiving a plurality of macroblocks, each frame of the video signal having an integer number of macroblocks;

means for selecting a refresh interval based upon network call rates and packet-loss error rates. wherein the selected refresh interval is an integer m, the integer m and factors of the integer m when divided into the integer number of macroblocks per frame do not give integer quotients; and

means for encoding a subset of the plurality of macroblocks as refresh intra-coded macroblocks based upon the selected refresh interval.

30. The system of claim 29 wherein the means for encoding encodes the subset of macroblocks by intra-coding every mth macroblock as a refresh intra-coded macroblock.