Effective prediction using partition coding
The way of predicting a current block by assigning constant partition values to the partitions of a bi-partitioning of a block is quite effective, especially in case of coding sample arrays such as depth/disparity maps where the content of these sample arrays is mostly composed of plateaus or simple connected regions of similar value separated from each other by steep edges. The transmission of such constant partition values would, however, still need a considerable amount of side information which should be avoided. This side information rate may be further reduced if mean values of values of neighboring samples associated or adjoining the respective partitions are used as predictors for the constant partition values.
1. 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 one or more refinement syntax elements indicating a first or second refinement value associated with a respective first or second portion of a predetermined block of a sample array, wherein the one or more refinement syntax elements are used to reconstruct the sample array using a plurality of operations including:
deriving a bi-partition of the predetermined block of the sample array into first and second portions;
associating each of neighboring samples of the sample array with a respective one of the first and second portions, the neighboring samples adjacent to the predetermined block;
predicting the predetermined block by assigning a first predicted value obtained based on values of the neighboring samples associated with the first portion to samples of the sample array positioned within the first portion, or assigning a second predicted value obtained based on values of the neighboring samples associated with the second portion to samples of the sample array positioned within the second portion;
retrieving, from the data stream, the one or more refinement syntax elements; and
refining the prediction of the predetermined block by applying the first refinement value to the first predicted value associated with the first partition, or applying the second refinement value to the second predicted value associated with the second partition.
2. The computer-readable medium according to claim 1 , wherein the first predicted value includes a mean of values of the neighboring samples associated with the first portion and the second predicted value includes a mean of values of the neighboring samples associated with the second portion.
3. The computer-readable medium according to claim 1 , wherein applying the first or second refinement value comprises scaling the first or second refinement value using a quantization step size depending on a reference quantization step size, wherein the data stream further comprises syntax elements representing the quantization step size or the reference quantization step size.
4. The computer-readable medium according to claim 3 , wherein the sample array is a depth map, and the plurality of operations comprises using the reference quantization step size in order to reconstruct, from the data stream, a texture sample array associated with the depth map.
5. The computer-readable medium according to claim 1 , wherein the deriving the bi-partition of the predetermined block comprises:
predicting a position of a wedgelet separation line within the predetermined block of the sample array depending on a wedgelet separation line of a neighboring block of the predetermined block such that the wedgelet separation line at the predicted position forms an extension of the wedgelet separation line of the neighboring block into the predetermined block and the wedgelet separation line of the predetermined block divides the predetermined block into the first and second portions, and refining the predicted position of the wedgelet separation line using line refinement information.
6. The computer-readable medium according to claim 1 , wherein the predetermined block is used to as a reference in a prediction loop for encoding or decoding other sample arrays.
7. The computer-readable medium according to claim 1 , wherein the one or more refinement syntax elements include a first syntax element indicating an absolute value of the first or second refinement value, and a second syntax element indicating a sign value of the first or second refinement value.
8. 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 one or more refinement syntax elements indicating a first or second refinement value associated with a respective first or second portion of a predetermined block of a sample array, wherein the one or more refinement syntax elements are encoded using a plurality of operations including:
deriving a bi-partition of the predetermined block of the sample array into first and second portions;
associating each of neighboring samples of the sample array with a respective one of the first and second portions, the neighboring samples adjacent to the predetermined block;
predicting the predetermined block by assigning a first predicted value obtained based on values of the neighboring samples associated with the first portion to samples of the sample array positioned within the first portion, or assigning a second predicted value obtained based on values of the neighboring samples associated with the second portion to samples of the sample array positioned within the second portion;
determining the first refinement value based on a first original value associated with the first portion and the first predicted value, or determining the second refinement value based on a second original value associated with the second portion and the second predicted value, wherein the first or second refinement value is applied to the first or second predicted value, respectively for refining the prediction of the predetermined block, and
encoding, into the data stream, the first or second refinement value as the one or more refinement syntax elements.
9. The computer-readable medium according to claim 8 , wherein the first predicted value includes a mean of values of the neighboring samples associated with the first portion and the second predicted value includes a mean of values of the neighboring samples associated with the second portion.
10. The computer-readable medium according to claim 8 , wherein the encoding the first or second refinement value comprises quantizing the first or second refinement value using a quantization step size depending on a reference quantization step size, wherein the data stream further comprises syntax elements representing the quantization step size or the reference quantization step size.
11. The computer-readable medium according to claim 10 , wherein the sample array is a depth map, and the plurality of operations comprises using the reference quantization step size in order to encode, into the data stream, a texture sample array associated with the depth map.
12. The computer-readable medium according to claim 8 , wherein the deriving the bi-partition of the predetermined block comprises:
predicting a position of a wedgelet separation line within the predetermined block of the sample array depending on a wedgelet separation line of a neighboring block of the predetermined block such that the wedgelet separation line at the predicted position forms an extension of the wedgelet separation line of the neighboring block into the predetermined block and the wedgelet separation line of the predetermined block divides the predetermined block into the first and second portions,
refining the predicted position of the wedgelet separation line using line refinement information, and
encoding the line refinement information into the data stream.
13. The computer-readable medium according to claim 8 , wherein the predetermined block is used to as a reference in a prediction loop for encoding or decoding other sample arrays.
14. The computer-readable medium according to claim 8 , wherein the one or more refinement syntax elements include a first syntax element indicating an absolute value of the first or second refinement value, and a second syntax element indicating a sign value of the first or second refinement value.