Methods and/or apparatus for controlling zero-residual coding in predictive image/video coding
View Patent ↗A method for coding video is disclosed. The method generally includes the steps of (A) receiving a video signal having a series of pictures, each of the pictures having a plurality of blocks, (B) analyzing the blocks to forecast if coding the blocks in a zero-residual coding mode would generate a plurality of artifacts, (C) disabling the zero-residual coding mode for the blocks forecasted to generate at least one of the artifacts and (D) enabling the zero-residual coding mode for the blocks forecasted to generate none of the artifacts.
1. A method for coding video, comprising the steps of:
(A) receiving a video signal having a series of pictures at an encoder, each of said pictures having a plurality of blocks;
(B) analyzing said blocks within an analysis module in said encoder to forecast if coding said blocks in a zero-residual coding mode would generate a plurality of artifacts; and
(C) determining said zero-residual coding mode in said encoder based on the analysis of said blocks, further comprising steps of:
(a) disabling said zero-residual coding mode for said blocks forecasted to generate at least one of said artifacts; and
(b) enabling said zero-residual coding mode for said blocks forecasted to generate none of said artifacts.
2. The method according to claim 1 , wherein step (B) comprises the sub-step of:
calculating a plurality of error values for a plurality of sub-blocks in each of said blocks by partially coding said sub-blocks in a predictive coding mode.
3. The method according to claim 2 , wherein step (C) comprises the sub-step of:
disabling said zero-residual coding mode for said blocks in which at least one of said error values forecasts at least one of said artifacts.
4. The method according to claim 2 , wherein step (B) further comprises the sub-step of:
forecasting at least one of said artifacts where at least one of said error values exceeds a respective adaptive threshold.
5. The method according to claim 2 , wherein step (B) further comprises the sub-step of:
forecasting at least one of said artifacts where at least one of said error values exceeds a respective fixed threshold.
6. The method according to claim 1 , wherein step (B) comprises the sub-step of:
calculating a plurality of prediction error values in a pixel domain for each of said blocks.
7. The method according to claim 6 , wherein step (B) further comprises the sub-step of:
forecasting at least one of said artifacts where at least one of said prediction error values exceeds a respective threshold.
8. The method according to claim 1 , wherein step (B) comprises the sub-steps of:
calculating a plurality of motion vector closeness values for each of said blocks; and
forecasting at least one of said artifacts where at least one of said motion vector closeness values exceeds a respective threshold.
9. The method according to claim 1 , wherein step (B) comprises the sub-steps of:
calculating a plurality of closeness values among plurality of motion vectors neighboring a current block of said blocks; and
forecasting at least one of said artifacts for said current block where a sum of said closeness values exceeds a respective threshold.
10. The method according to claim 1 , wherein step (B) comprises the sub-step of:
calculating a plurality of discrete coefficients in a transform domain for each of said blocks, wherein said discrete coefficients are one group of (i) a plurality of transform coefficients and (ii) a plurality of quantization coefficients.
11. The method according to claim 10 , wherein step (B) further comprises the sub-step of:
forecasting at least one of said artifacts where a number of non-zero coefficients among said discrete coefficients exceeds a respective threshold.
12. The method according to claim 10 , wherein step (B) further comprises the sub-step of:
forecasting at least one of said artifacts where at least one of said discrete coefficients exceeds a respective threshold.
13. The method according to claim 10 , wherein step (B) further comprises the sub-step of:
forecasting at least one of said artifacts where a sum of said discrete coefficients exceeds a respective threshold.
14. An apparatus comprising:
a memory configured to buffer a video signal having a series of pictures, each of said pictures having a plurality of blocks; and
a processor configured to
(i) analyze a particular one of said blocks to determine if coding said particular block in a zero-residual coding mode would generated at least one artifact, and
(ii) determine said zero-residual coding mode based on the analysis of said particular block by
(a) disabling said zero-residual coding mode where said particular block would generate said at least one artifact and (b) enabling said zero-residual coding mode where said particular block would not generate said at least one artifact.
15. The apparatus according to claim 14 , wherein said processor is further configured to generate a plurality of threshold values used to determine if said particular block would generate said at least one artifact, one of said threshold values being generated for each of a plurality of sub-blocks within said particular block.
16. The apparatus according to claim 15 , wherein said processor is further configured to calculate said threshold values using a just noticeable difference model operating on a plurality of average sample values neighboring said sub-blocks.
17. The apparatus according to claim 15 , wherein said processor is further configured to calculate said threshold values based on at least one quantization parameter corresponding to said sub-blocks.
18. The apparatus according to claim 15 , wherein said processor comprises:
an encoder module configured to encode said video signal;
an analysis module configured to analyze said particular block;
a control module configured to (i) disable said zero-residual coding mode and (ii) enable said zero-residual coding mode; and
a threshold module configured to generate said threshold values.
19. The apparatus according to claim 14 , wherein said zero-residual coding mode comprises (i) at least one inter-coding mode that does not code a residual and (ii) at least one intra-coding mode that does not code a residual.
20. An apparatus comprising:
means for receiving a video signal within an encoder, the video signal comprising a series of pictures, each of said pictures having a plurality of blocks;
means for analyzing said blocks to forecast if coding said blocks using a zero-residual coding mode would generated a plurality of artifacts, the zero-encoding mode being set by a control within the encoder; and
means for determining said zero-residual coding mode based on the analysis of said blocks in the encoder by (i) disabling said zero-residual coding mode for said blocks forecasted to generate at least one of said respective artifacts and (ii) enabling said zero-residual coding mode for said blocks forecasted to generate none of said respective artifacts.