Method and apparatus for vector encoding in video coding and decoding

Patent metadata

Field	Value
Publication number	US-2016100186-A1
Application number	US-201514874170-A
Country	US
Kind code	A1
Filing date	Oct 2, 2015
Priority date	Oct 6, 2014
Publication date	Apr 7, 2016
Grant date	—

Abstract

The present invention concerns a method of encoding an image, the image comprising a plurality of coding elements made of blocks of pixels, each block of pixels being encoded according to a coding mode out of a plurality of coding modes, the method comprising for each block of pixel to be encoded determining the coding mode to be used for the encoding of a given block of pixels by sequentially evaluating some coding modes in the plurality of coding modes; wherein the method comprises evaluating Inter coding modes and fast IBC coding modes; and no residue-test is conducted between the evaluation of the Inter coding mode and the evaluation of the fast IBC mode. Accordingly, some good predictors may be found more rapidly and the whole encoding process is speed up.

First claim

1 . A method of encoding an image, the image comprising a plurality of coding elements made of blocks of pixels, each block of pixels being encoded according to a coding mode out of a plurality of coding modes, the method comprising for each block of pixel to be encoded:
determining the coding mode to be used for the encoding of a given block of pixels by sequentially evaluating some coding modes in the plurality of coding modes; wherein the method comprises: evaluating Inter coding modes and fast IBC coding modes; and no residue-test is conducted between the evaluation of the Inter coding mode and the evaluation of the fast IBC mode.

2 . The method of claim 1 , wherein Inter coding modes and fast IBC coding modes are evaluated in sequence.

3 . The method of claim 1 , wherein the method further comprises:
evaluating Intra coding modes and classical IBC coding modes in sequence after the evaluation of Inter coding modes and fast IBC coding modes.

4 . The method of claim 1 , wherein the method further comprises:
conducting a residue-test after evaluation of fast IBC coding modes to early terminate coding mode evaluation in case a coding mode leading to no residue has been found.

5 . The method of claim 3 , wherein:
no residue-test is conducted between the evaluation of the Intra coding mode and the evaluation of the classical IBC mode.

6 . The method according to claim 1 wherein said method further comprises:
evaluating first the Skip coding mode; and
further evaluation steps are only conducted if the Skip coding mode has not been selected.

7 . The method of claim 1 , wherein fast IBC coding modes and Inter coding modes are evaluated in sequence.

8 . The method of claim 7 , wherein the method further comprises:
next evaluating Intra coding mode and classical IBC mode.

9 . A method of encoding an image, the image comprising a plurality of coding elements made of blocks of pixels, each block of pixels being encoded according to a coding mode out of a plurality of coding modes, the method comprising for each block of pixel to be encoded:
determining the coding mode to be used for the encoding of a given block of pixels by sequentially evaluating some coding modes in the plurality of coding modes; wherein the method comprises: evaluating first the Skip coding mode; and evaluating next the fast IBC coding modes if the Skip coding mode has not been selected.

10 . The method of claim 9 , further comprising next:
evaluating the Inter coding mode, the Intra coding mode and the classical IBC mode; and conducting a residue-test after evaluation of fast IBC coding modes to early terminate coding mode evaluation of coding modes in case a coding mode leading to no residue has been found.

11 . A method of encoding an image, the image comprising a plurality of coding elements made of blocks of pixels, each block of pixels being encoded according to a coding mode out of a plurality of coding modes, the method comprising for each block of pixel to be encoded:
determining the coding mode to be used for the encoding of a given block of pixels by sequentially evaluating some coding modes in the plurality of coding modes; wherein the method comprises: evaluating the fast IBC coding mode.

12 . The method of claim 11 , wherein the fast IBC coding mode is evaluated first.

13 . The method of claim 12 , further comprising:
evaluating next the Inter hash based coding mode.

14 . The method of claim 12 , further comprising:
evaluating next the Intra coding mode and the classical IBC mode; and conducting a residue-test after the evaluation of fast IBC coding modes to early terminate coding mode evaluation of coding modes in case a coding mode leading to no residue has been found, a residue-test being a test to determine if so far a predictor block of pixels has been found during the evaluation leading to an encoding of the current block of pixels without residue.

15 . The method of claim 12 , wherein the method comprises:
conducting a residue-test after evaluation of the fast IBC coding modes to early terminate coding mode evaluation of coding modes in case a coding mode leading to no residue has been found.

16 . A method of encoding an image, the image comprising a plurality of coding elements made of blocks of pixels, each block of pixels being encoded according to a mode out of a plurality of modes, some of these modes comprising the encoding of the block of pixels based on a predictor block, this predictor block being designed by a block vector giving its location in the image it belongs to relatively to the current block of pixel being encoded, the method comprising:
during the encoding of a first coding unit, storing in a cache memory block vectors determined as designating good predictor blocks for this first coding unit; first testing predictor blocks designed by block vectors stored in the cache memory for at least some encoding mode during the encoding of a second coding unit.

17 . The method of claim 16 , one mode being called INTRA Block Copy mode in which the block is encoded based on a predictor block being an actual block of the current image, wherein:
said block vectors stored in the memory cache are determined when testing INTRA Block Copy mode for said first coding unit; and first testing predictor blocks designed by block vectors stored in the cache memory for INTRA Block Copy mode during the encoding of a second coding unit.

18 . The method of claim 16 , wherein the block vectors from the cache memory tested first during the encoding of the second unit have been determined as designating good predictor blocks for coding unit in the neighbourhood of said second unit.

19 . The method of claim 17 , wherein the method comprises for a given coding unit:
testing a given number of INTER prediction modes; testing a given number of INTRA prediction modes; and wherein: testing a given number of block vectors from the cache memory according to INTRA Block Copy mode is carried on after the testing of INTER prediction modes and before the testing of INTRA prediction modes.

20 . The method of claim 19 , wherein if testing some block vectors from the cache memory according to INTRA Block Copy mode satisfies a predetermined criterion, the method comprises skipping the step of testing INTRA prediction modes.

21 . The method according to claim 17 , wherein the method comprises for testing at least some INTRA Block Copy prediction modes:
testing only predictor blocks designed by block vectors stored in the cache memory.

22 . The method according to claim 16 , wherein each block vector stored in the cache memory is only stored once.

23 . The method of claim 16 , one mode being called INTER mode in which the block is encoded based on a predictor block being an actual block of another image, wherein:
said block vectors stored in the memory cache are determined when testing INTER mode for said first coding unit; and first testing predictor blocks designed by the block vectors stored in the cache memory for INTER mode during the encoding of a second coding unit.

24 . The method of claim 16 , one mode being called INTER mode in which the block is encoded based on a predictor block being an actual block of another image, one mode being called INTRA Block Copy mode in which the block is encoded based on a predictor block being an actual block of the same image wherein:
said block vectors

Assignees

• Canon Kk

Inventors

• Gisquet Christophe
• Laroche Guillaume
• Onno Patrice

Classifications

• H04N19/107

  between spatial and temporal predictive coding, e.g. picture refresh · CPC title

• H04N19/52

  by predictive encoding · CPC title

• H04N19/119

  Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks · CPC title

• H04N19/147

  according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567) · CPC title

• H04N19/132

  Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking · CPC title