Effective wedgelet partition coding

1. A decoder for reconstructing a sample array of a video from a data stream, the decoder configured to:

determine a set of wedgelet patterns to decode a block of the sample array of the video, wherein each wedgelet pattern of the set corresponds to a line defined by a start position and an end position, the line dividing the corresponding wedgelet pattern into two wedgelet portions;

extract, from the data stream, information related to a selected wedgelet pattern of the set of wedgelet patterns;

obtain the selected wedgelet pattern from the set of wedgelet patterns based on the information; and

decode the block based on the two wedgelet portions yielded by the line corresponding to the selected wedgelet pattern.

2. The decoder of claim 1 , wherein the set is generated by checking whether a third wedgelet pattern is an inverse of a fourth wedgelet pattern already in the set, and responsive to a determination that the third wedgelet pattern is not inverse of the fourth wedgelet pattern, inserting the third wedgelet pattern in the set.

3. The decoder of claim 1 , wherein the decoder is configured to determine a plurality of sets of wedgelet patterns, wherein each set of the plurality of sets corresponds to one of a plurality of sizes of blocks of the sample array of the video.

4. The decoder of claim 1 , wherein each wedgelet pattern of the set is a two-dimensional array including binary-valued elements.

5. The decoder of claim 1 , wherein the information includes an index value, which is represented in a fixed number of bits in the data stream, and the decoder is configured to decode the index value based on fixed-length coding.

6. The decoder of claim 1 , wherein a number of wedgelet patterns in the set varies in accordance with a size of the block.

7. The decoder of claim 1 , wherein the selected wedgelet pattern is an array having elements all with a first binary value, the decoder is configured to update first elements of the array from the first binary value to a second binary value, wherein the first elements form a line joining start and end positions of the selected wedgelet pattern.

8. The decoder of claim 1 , wherein the set is generated by checking whether a first wedgelet pattern is identical to a second wedgelet pattern already in the set, and responsive to a determination that the first wedgelet pattern is not identical to the second wedgelet pattern, inserting the first wedgelet pattern in the set.

9. The decoder of claim 1 , wherein the decoder is configured to, in decoding the block, predict the block by assigning a first constant partition value to samples of the sample array positioned within a first of the two wedgelet portions and a second constant partition value to samples of the sample array positioned within a second of the two wedgelet portions.

10. The decoder of claim 9 , wherein the sample array is a depth map, and the decoder is configured to use a reference quantization step size in order to reconstruct a texture sample array from the data stream, with which the depth map is associated.

11. The decoder of claim 10 , further configured to use the block as a reference in a prediction loop of the decoder.

12. An encoder for encoding a sample array of a video into a data stream, the encoder configured to:

generate a set of wedgelet patterns to encode a block of the sample array of the video, wherein each wedgelet pattern of the set corresponds to a line defined by a start position and an end position, the line dividing the corresponding wedgelet pattern into two wedgelet portions;

obtain, for the block of the sample array of the video, a selected wedgelet pattern from the set of wedgelet patterns;

insert, into the data stream, information related to the selected wedgelet pattern; and

encode the block based on the two wedgelet portions yielded by the line corresponding to the selected wedgelet pattern.

13. The encoder of claim 12 , wherein to generate the set, the encoder is configured to check whether a third wedgelet pattern is an inverse of a fourth wedgelet pattern already in the set, and responsive to a determination that the third wedgelet pattern is not inverse of the fourth wedgelet pattern, insert the third wedgelet pattern in the set.

14. The encoder of claim 12 , wherein the encoder is configured to determine a plurality of sets of wedgelet patterns, wherein each set of the plurality of sets corresponds to one of a plurality of sizes of blocks of the sample array of the video.

15. The encoder of claim 12 , the information includes an index value, which is represented in a fixed number of bits in the data stream, and the encoder is configured to encode the index value based on fixed-length coding.

16. The encoder of claim 12 , wherein a number of wedgelet patterns in the set varies in accordance with a size of the block.

17. The encoder of claim 12 , wherein the selected wedgelet pattern is an array having elements all with a first binary value, the encoder is configured to update first elements of the array from the first binary value to a second binary value, wherein the first elements form a line joining start and end positions of the selected wedgelet pattern.

18. 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 information related to a selected wedgelet pattern in a set of wedgelet patterns generated for a block of a sample array of a video, wherein the block is encoded into the data stream based on a plurality of operations comprising:

generating a set of wedgelet patterns to encode a block of the sample array of the video, wherein each wedgelet pattern of the set corresponds to a line defined by a start position and an end position, the line dividing the corresponding wedgelet pattern into two wedgelet portions;

obtaining, for the block of the sample array of the video, a selected wedgelet pattern from the set of wedgelet patterns;

inserting, into the data stream, the information related to the selected wedgelet pattern; and

encoding the block based on the two wedgelet portions yielded by the line corresponding to the selected wedgelet pattern.

19. The decoder of claim 1 , wherein the information includes one or more syntax elements indicating a direction, an offset, or a sign related to the selected wedgelet pattern.

20. The encoder of claim 12 , wherein the information includes one or more syntax elements indicating a direction, an offset, or a sign related to the selected wedgelet pattern.