Coding of a spatial sampling of a two-dimensional information signal using sub-division

• US 10,856,013 B2
• Filed: 11/20/2018
• Issued: 12/01/2020
• Est. Priority Date: 04/13/2010
• Status: Active Grant

• Current Assignee: GE Video Compression, LLC (General Electric Company)
• Original Assignee: GE Video Compression, LLC (General Electric Company)
• Inventors: Kirchhoffer, Heiner, Winken, Martin, Helle, Philipp, Marpe, Detlev, Schwarz, Heiko, Wiegand, Thomas
• Primary Examiner(s): Retallick, Kaitlin A
• Application Number:
  US16/197,232
• Publication Number:
  US 20190089992A1
• Time in Patent Office: 742 Days
• Field of Search: None
• CPC Class Codes: H04N 19/119 Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/1883 the unit relating to sub-band structure, e.g. hierarchical level, directional tree, e.g. low-high [LH], high-low [HL], high-high [HH]
• 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 19/52 by predictive encoding
• CPC Class Codes: H04N 19/53 Multi-resolution motion estimation; Hierarchical motion estimation
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/96 Tree coding, e.g. quad-tree coding

Abstract

Coding schemes for coding a spatially sampled information signal using sub-division and coding schemes for coding a sub-division or a multitree structure are described, wherein representative embodiments relate to picture and/or video coding applications.

Claims

1. A decoder comprising:

an extractor configured to extract, from a data stream representing encoded video information, information related to first and second maximum region sizes, first and second subdivision information, and a maximum hierarchy level, wherein the first maximum region size and the first subdivision information are associated with prediction coding, and the second maximum region size and the second subdivision information are associated with transform coding;

a divider configured to;

divide an array of information samples representing a spatially sampled portion of the video information into a first set of root regions based on the first maximum region size,

sub-divide at least some of the first set of root regions into a first set of sub-regions using recursive multi-tree partitioning based on the first subdivision information,

based on the size of at least one of the first set of sub-regions and the second maximum region size, divide at least one of the first set of sub-regions into a second set of root regions of the second maximum region size, wherein the second subdivision information includes flag syntax elements encoded in the data stream and different from the information related to second maximum region size, each flag syntax element being associated with a corresponding root region of the second set of root regions and having a binary value,

determine, for each of the second set of root regions of the second maximum region size, whether the respective root region of the second set of root regions is to be sub-divided based on the corresponding flag syntax element, and

responsive to a determination that the corresponding flag syntax element is equal to the binary value of 1, sub-divide the respective root region of the second set of root regions into a second set of sub-regions using recursive multi-tree partitioning based on the second subdivision information and the maximum hierarchy level; and

a reconstructor configured to reconstruct the array of information samples using prediction coding in accordance with the first set of sub-regions and transform coding in accordance with the second set of sub-regions.

2. The decoder according to claim 1, wherein the reconstructor is configured to, for a sub-region of the first set of sub-regions:

compute a prediction signal based on an intra-prediction mode associated with the sub-region and reconstructed samples of a neighboring subset of the second set of sub-regions, compute a reconstructed signal by adding the prediction signal to a reconstructed residual of a subset of the second set of sub-regions associated with the sub-region, and store the reconstructed signal in a buffer for a next intra-prediction cycle.

3. The decoder according to claim 1, wherein the divider is configured to perform the division of the array of information samples into the first set of root regions such that the first set of root regions are rectangular blocks of a size determined by the first maximum region size, the rectangular blocks are arranged in an order to gaplessly cover the array of information samples.

4. The decoder according to claim 1, wherein the divider is configured to, in sub-dividing at least some of the first set of root regions,

determine whether the first subdivision information indicates that each of the at least some of the first set of root regions is to be sub-divided,

based on a determination that each of the at least some of the first set of root regions is to be sub-divided, sub-divide that root region into sub-regions of a first hierarchy level according to a partition rule associated with the first hierarchy level, and

recursively repeat the determination and sub-division for the sub-regions of the first hierarchy level in order to obtain regions of higher-order hierarchy levels using respective partition rules associated therewith,

wherein the determination and sub-division is performed until no further division is to be performed according to the first subdivision.

5. The decoder according to claim 4, wherein the divider is configured to, in accordance with the partition rules associated with the first and higher-order hierarchy levels, sub-divide into sub-regions of equal size, such that there are an equal number of sub-regions at each hierarchy level.

6. The decoder according to claim 4, wherein the first subdivision information includes a partition indication flag indicating whether any of the first set of root regions or the sub-regions at the first or higher-order hierarchy level is sub-divided.

7. The decoder according to claim 1, wherein the extractor is configured to extract syntax elements associated with the first or second set of sub-regions from the data stream in a depth-first traversal order.

8. The decoder according to claim 1, further comprising:

a merger configured to combine, based on a first subset of syntax elements of the data stream, disjoint from a second subset of syntax elements of the data stream including the first subdivision information, spatially neighboring ones of the first set of sub-regions to obtain an intermediate subdivision of the array of information samples, wherein the reconstructor is configured to reconstruct the array of information samples using the intermediate subdivision.

9. The decoder according to claim 1, further comprising:

a predictor configured to predict the array of information samples from the data stream, wherein the reconstructor is configured to perform a spectral-to-spatial domain transform coding to obtain a residual for the array of information samples, and combine the residual and the prediction of the array of information samples to reconstruct the array of information samples.

10. The decoder according to claim 1, wherein the recursive multi-tree partitioning includes a quadtree partitioning technique.

11. A method for decoding comprising:

extracting, from a data stream representing encoded video information, information related to first and second maximum region sizes, first and second subdivision information, and a maximum hierarchy level, wherein the first maximum region size and the first subdivision information are associated with prediction coding, and the second maximum region size and the second subdivision information are associated with transform coding;

dividing an array of information samples representing a spatially sampled portion of the video information into a first set of root regions based on the first maximum region size;

sub-dividing at least some of the first set of root regions into a first set of sub-regions using recursive multi-tree partitioning based on the first subdivision information;

based on the size of at least one of the first set of sub-regions and the second maximum region size, dividing at least one of the first set of sub-regions into a second set of root regions of the second maximum region size, wherein the second subdivision information includes flag syntax elements encoded in the data stream and different from the information related to second maximum region size, each flag syntax element being associated with a corresponding root region of the second set of root regions and having a binary value;

determining, for each of the second set of root regions of the second maximum region size, whether the respective root region of the second set of root regions is to be sub-divided based on the corresponding flag syntax element;

responsive to a determination that the corresponding flag syntax element is equal to the binary value of 1, sub-dividing the respective root region of the second set of root regions into a second set of sub-regions using recursive multi-tree partitioning based on the second subdivision information and the maximum hierarchy level; and

reconstructing the array of information samples using prediction coding in accordance with the first set of sub-regions and transform coding in accordance with the second set of sub-regions.

12. The method according to claim 11, wherein, for a sub-region of the first set of sub-regions, the reconstructing includes:

computing a prediction signal based on an intra-prediction mode associated with the sub-region and reconstructed samples of a neighboring subset of the second set of sub-regions, computing a reconstructed signal by adding the prediction signal to a reconstructed residual of a subset of the second set of sub-regions associated with the sub-region, and storing the reconstructed signal in a buffer for a next intra-prediction cycle.

13. The method according to claim 11, wherein the dividing of the array of information samples into the first set of root regions is performed such that the first set of root regions are rectangular blocks of a size determined by the first maximum region size, the rectangular blocks are arranged in an order to gaplessly cover the array of information samples.

14. The method according to claim 11, wherein the sub-dividing at least some of the first set of root regions includes:

determining whether the first subdivision information indicates that each of the at least some of the first set of root regions is to be sub-divided,

based on a determination that each of the at least some of the first set of root regions is to be sub-divided, sub-dividing that root region into sub-regions of a first hierarchy level according to a partition rule associated with the first hierarchy level, and recursively repeating the determination and sub-division for the sub-regions of the first hierarchy level in order to obtain regions of higher-order hierarchy levels using respective partition rules associated therewith, wherein the determination and sub-division is performed until no further division is to be performed according to the first subdivision.

15. The method according to claim 14, wherein, in accordance with the partition rules associated with the first and higher-order hierarchy levels, the sub-dividing includes sub-dividing into sub-regions of equal size such that there are an equal number of sub-regions at each hierarchy level.

16. The method according to claim 14, wherein the first subdivision information includes a partition indication flag indicating whether any of the first set of root regions or the sub-regions at the first or higher-order hierarchy level is sub-divided.

17. The method according to claim 11, further comprising extracting syntax elements associated with the first or second set of sub-regions from the data stream in a depth-first traversal order.

18. The method according to claim 11, further comprising:

combining, based on a first subset of syntax elements of the data stream, disjoint from a second subset of syntax elements of the data stream including the first subdivision information, spatially neighboring ones of the first set of sub-regions to obtain an intermediate subdivision of the array of information samples, wherein the reconstructor is configured to reconstruct the array of information samples using the intermediate subdivision.

19. The method according to claim 11, further comprising:

predicting the array of information samples from the data stream,

wherein the reconstructing includes performing a spectral-to-spatial domain transform coding to obtain a residual for the array of information samples, and combining the residual and the prediction of the array of information samples to reconstruct the array of information samples.

20. The method according to claim 11, wherein the recursive multi-tree partitioning includes a quadtree partitioning technique.

21. An encoder comprising:

a divider configured to;

divide an array of information samples representing a spatially sampled portion of video information into a first set of root regions based on a first maximum region size,

sub-divide at least some of the first set of root regions into a first set of sub-regions using recursive multi-tree partitioning based on first subdivision information,

based on a size of at least one of the first set of sub-regions and a second maximum region size, divide at least one of the first set of sub-regions into a second set of root regions of the second maximum region size, wherein second subdivision information includes flag syntax elements different from the second maximum region size, each flag syntax element being associated with a corresponding root region of the second set of root regions and having a binary value,

determine, for each of the second set of root regions of the second maximum region size, whether the respective root region of the second set of root regions is to be sub-divided based on the corresponding flag syntax element, and

responsive to a determination that the corresponding flag syntax element is equal to the binary value of 1, sub-divide the respective root region of the second set of root regions into a second set of sub-regions using recursive multi-tree partitioning based on the second subdivision information and a maximum hierarchy level; and

a data stream generator configured to;

encode the array of information samples using prediction coding in accordance with the first set of sub-regions and transform coding in accordance with the second set of sub-regions, and

insert into a data stream the encoded array of information samples, information related to the first and second maximum region sizes and the maximum hierarchy level, and the first and second subdivision information including the flag syntax elements, wherein the first maximum region size and the first subdivision information are associated with prediction coding, and the second maximum region size and the second subdivision information are associated with transform coding.

22. The encoder according to claim 21, wherein the data stream generator is configured to, for a sub-region of the first set of sub-regions:

compute a prediction signal based on an intra-prediction mode associated with the sub-region and reconstructed samples of a neighboring subset of the second set of sub-regions, compute a reconstructed signal by adding the prediction signal to a reconstructed residual of a subset of the second set of sub-regions associated with the sub-region, and

store the reconstructed signal in a buffer for a next intra-prediction cycle.

23. The encoder according to claim 21, wherein the divider is configured to perform the division of the array of information samples into the first set of root regions such that the first set of root regions are rectangular blocks of a size determined by the first maximum region size, the rectangular blocks are arranged in an order to gaplessly cover the array of information samples.

24. The encoder according to claim 21, wherein the divider is configured to, in sub-dividing at least some of the first set of root regions,

determine whether the first subdivision information indicates that each of the at least some of the first set of root regions is to be sub-divided,

based on a determination that each of the at least some of the first set of root regions is to be sub-divided, sub-divide that root region into sub-regions of a first hierarchy level according to a partition rule associated with the first hierarchy level, and

recursively repeat the determination and sub-division for the sub-regions of the first hierarchy level in order to obtain regions of higher-order hierarchy levels using respective partition rules associated therewith,

wherein the determination and sub-division is performed until no further division is to be performed according to the first subdivision.

25. The encoder according to claim 24, wherein the divider is configured to, in accordance with the partition rules associated with the first and higher-order hierarchy levels, sub-divide into sub-regions of equal size, such that there are an equal number of sub-regions at each hierarchy level.

26. The encoder according to claim 24, wherein the first subdivision information includes a partition indication flag indicating whether any of the first set of root regions or the sub-regions at the first or higher-order hierarchy level is sub-divided.

27. The encoder according to claim 21, wherein the data stream generator is configured to insert syntax elements associated with the first or second set of sub-regions from the data stream in a depth-first traversal order.

28. The encoder according to claim 21, further comprising:

a merger configured to combine, based on a first subset of syntax elements of the data stream, disjoint from a second subset of syntax elements of the data stream including the first subdivision information, spatially neighboring ones of the first set of sub-regions to obtain an intermediate subdivision of the array of information samples,

wherein the data stream generator is configured to encode the array of information samples using the intermediate subdivision.

29. The encoder according to claim 21, wherein the recursive multi-tree partitioning includes a quadtree partitioning technique.

30. A non-transitory computer-readable medium for storing data associated with a video, comprising:

a data stream stored in the non-transitory computer-readable medium, the data stream comprising an encoded array of information samples, information related to first and second maximum region sizes and a maximum hierarchy level, and first and second subdivision information, wherein the first maximum region size and the first subdivision information are associated with prediction coding, and the second maximum region size and the second subdivision information are associated with transform coding,

wherein the array of information samples is encoded into the data stream based on operations including;

dividing an array of information samples representing a spatially sampled portion of video information into a first set of root regions based on a first maximum region size, sub-dividing at least some of the first set of root regions into a first set of sub-regions using recursive multi-tree partitioning based on first subdivision information,

based on a size of at least one of the first set of sub-regions and a second maximum region size, dividing at least one of the first set of sub-regions into a second set of root regions of the second maximum region size, wherein the second subdivision information includes flag syntax elements encoded in the data stream and different from the information related to second maximum region size, each flag syntax element being associated with a corresponding root region of the second set of root regions and having a binary value,

determining, for each of the second set of root regions of the second maximum region size, whether the respective root region of the second set of root regions is to be sub-divided based on the corresponding flag syntax element,

responsive to a determination that the corresponding flag syntax element is equal to the binary value of 1, sub-dividing the respective root region of the second set of root regions into a second set of sub-regions using recursive multi-tree partitioning based on second subdivision information and a maximum hierarchy level,

encoding the array of information samples using prediction coding in accordance with the first set of sub-regions and transform coding in accordance with the second set of sub-regions, and

inserting into the data stream the encoded array of information samples, the information related to the first and second maximum region sizes and the maximum hierarchy level, and the first and second subdivision information including the flag syntax elements.