Multitree subdivision and inheritance of coding parameters in a coding block
A better compromise between encoding complexity and achievable rate distortion ratio, and/or to achieve a better rate distortion ratio is achieved by using multitree sub-divisioning not only in order to subdivide a continuous area, namely the sample array, into leaf regions, but using the intermediate regions also to share coding parameters among the corresponding collocated leaf blocks. By this measure, coding procedures performed in tiles—leaf regions—locally, may be associated with coding parameters individually without having to, however, explicitly transmit the whole coding parameters for each leaf region separately. Rather, similarities may effectively exploited by using the multitree subdivision.
1. A decoder for reconstructing an array of information samples encoded in a data stream, the array of information samples including spatially sampled information samples with regions of different sizes, comprising a processor;
an extractor configured for, using the processor,
extracting, from the data stream, multi-tree subdivision information and inheritance information associated with an inheritance region including a set of leaf regions, wherein each of the leaf regions has associated therewith a size and is to be reconstructed based on one or more coding parameters,
subdividing, based on the multi-tree subdivision information, the array of information samples into a plurality of regions including the inheritance region, wherein each of the plurality of regions is associated with one of a plurality of hierarchy levels associated with multi-tree subdivision of the array,
determining, using the inheritance information, whether or not inheritance is to be used for the inheritance region for sharing at least one coding parameter among the set of leaf regions based on the size of the leaf region within the inheritance region, wherein regions at different hierarchy levels of the plurality of hierarchy levels have different degrees of sharing of coding information via inheritance, and
responsive to a determination that the inheritance is to be used, extracting, from the data stream, at least one syntax element associated with the inheritance region, the at least one syntax element representing a set of coding parameters including a coding parameter used in residual coding of the set of leaf regions to be shared among the set of leaf regions, which are decoded in a depth-first traversal order; and
a predictor configured for generating, using the processor, for each of the set of leaf regions, a respective prediction signal based on the shared at least one syntax element inherited from the inheritance region, wherein each of the set of leaf regions is reconstructed based on the respective prediction signal.
2. The decoder according to claim 1 , wherein for each inheritance region corresponding to a hierarchy level defined by the multi-tree subdivision, the decoder is configured for checking, based on the inheritance information associated with the inheritance region, whether the inheritance is to be used,
when the inheritance is to be used, the extractor is further configured for
extracting, from the data stream, an inheritance set of coding parameters associated with the inheritance region, and
copying the inheritance set of coding parameters to a corresponding inheritance subset of coding parameters associated with each of leaf regions which constitute the inheritance region without further extracting coding parameters for each of the leaf regions.
3. The decoder according to claim 2 , wherein the decoder is a hybrid decoder.
4. The decoder according to claim 1 , wherein the decoder is configured to decode a residual for each of the set of leaf regions.
5. The decoder according to claim 1 , wherein the extractor is configured to extract, from the data stream, at least one syntax element representing the coding parameters associated with each of the set of leaf regions when the inheritance region has its corresponding inheritance information indicating no use of inheritance.
6. The decoder according to claim 5 , wherein the extractor is configured to, if inheritance is indicated not to be used, extract the coding parameters associated with each of the set of leaf regions.
7. The decoder according to claim 1 , wherein the decoder is configured to reconstruct the array of information samples of each of the set of leaf regions by prediction using a prediction mode determined based on the at least one syntax element.
8. The decoder according to claim 1 , wherein the at least one syntax element represents a coding parameter related to an interpolation filter used in decoding the set of leaf regions.
9. A method for reconstructing an array of information samples encoded in a data stream, the array of information samples including spatially sampled information samples with regions of different sizes, comprising:
extracting, from the data stream, multi-tree subdivision information and inheritance information associated with an inheritance region including a set of leaf regions, wherein each of the leaf regions has associated therewith a size and is to be reconstructed based on one or more coding parameters;
subdividing, based on the multi-tree subdivision information, the array of information samples into a plurality of regions including the inheritance region, wherein each of the plurality of regions is associated with one of a plurality of hierarchy levels associated with multi-tree subdivision of the array;
determining, using the inheritance information whether or not inheritance is to be used for the inheritance region for sharing at least one coding parameter among the set of leaf regions based on the size of the leaf region within the inheritance region, wherein regions at different hierarchy levels of the plurality of hierarchy levels have different degrees of sharing of coding information via inheritance;
responsive to a determination that the inheritance is to be used, extracting, from the data stream, at least one syntax element associated with the inheritance region, the at least one syntax element representing a set of coding parameters including a coding parameter used in residual coding of the set of leaf regions to be shared among the set of leaf regions, which are decoded in a depth-first traversal order;
generating, for each of the set of leaf regions, a respective prediction signal based on the shared at least one syntax element inherited from the inheritance region; and
reconstructing each of the subset of leaf regions based on the respective prediction signal.
10. The method according to claim 9 , further comprising, for each inheritance region corresponding to a hierarchy level defined by the multi-tree subdivision,
checking, based on the inheritance information associated with the inheritance region, whether the inheritance is to be used,
when an inheritance is to be used, extracting, from the data stream, an inheritance set of coding parameters associated with the inheritance region, and
copying the inheritance set of coding parameters to a corresponding inheritance subset of coding parameters associated with each of leaf regions which constitute the inheritance region without further extracting coding parameters for each of the leaf regions.
11. The method according to claim 9 , further comprising decoding a residual for each of the set of leaf regions.
12. The method according to claim 9 , further comprising extracting, from the data stream, at least one syntax element representing the coding parameters associated with each of the set of leaf regions when the inheritance region has its corresponding inheritance information indicating no use of inheritance.
13. The method according to claim 12 , further comprising, if inheritance is indicated not to be used, extracting the coding parameters associated with each of the set of leaf regions.
14. The method according to claim 9 , further comprising reconstructing the array of information samples of each of the set of leaf regions by prediction using a prediction mode determined based on the at least one syntax element.
15. The method according to claim 9 , wherein the at least one syntax element represents a coding parameter related to an interpolation filter used in decoding the set of leaf regions.
16. A non-transitory computer readable digital storage medium having stored thereon a computer program, wherein the computer program, when read by the computer, causes the computer to perform a method according to claim 9 .
17. An encoder for encoding into a data stream an array of information samples including spatially sampled information samples with regions of different sizes, comprising a processor;
an inserter for, using the processor,
inserting, into the data stream, multi-tree subdivision information relating to the subdivision and inheritance information associated with an inheritance region including a set of leaf regions, wherein each of the leaf regions has associated therewith a size and is to be reconstructed based on one or more coding parameters,
subdividing, based on the multi-tree subdivision information, the array of information samples into a plurality of regions including the inheritance region, wherein each of the plurality of regions is associated with one of a plurality of hierarchy levels associated with multi-tree subdivision of the array,
determining, using the inheritance information, whether or not inheritance is to be used for the inheritance region for sharing at least one coding parameter among the set of leaf regions based on the size of the leaf region within the inheritance region, wherein regions at different hierarchy levels of the plurality of hierarchy levels have different degrees of sharing of coding information via inheritance, and
responsive to a determination that the inheritance is to be used, inserting, into the data stream, at least one syntax element associated with the inheritance region, the at least one syntax element representing a set of coding parameter including a coding parameter used in residual coding of the set of leaf regions to be shared among the set of leaf regions, without inserting corresponding at least one coding parameter of each of the set of leaf regions, which are decoded in a depth-first traversal order,
wherein the at least one syntax element is to be used, during decoding, to generate, for each of the set of leaf regions, a respective prediction signal based on the shared at least one syntax element inherited from the inheritance region, and reconstruct each of the subset of leaf regions based on the respective prediction signal.
18. The encoder according to claim 17 , wherein the encoder is configured to encode a residual for each of the set of leaf regions.
19. The encoder according to claim 17 , wherein the inserter is configured to insert, into the data stream, at least one syntax element representing the coding parameters associated with each of the set of leaf regions when the inheritance region has its corresponding inheritance information indicating no use of inheritance.
20. The encoder according to claim 19 , wherein the inserter is configured to, if inheritance is indicated not to be used, insert the coding parameters associated with each of the set of leaf regions.
21. The encoder according to claim 17 , wherein each of the set of leaf regions is reconstructed by prediction using a prediction mode determined based on the at least one syntax element.
22. The encoder according to claim 17 , wherein the at least one syntax element represents a coding parameter related to an interpolation filter used in coding the set of leaf regions.
23. 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 regarding an array of information samples including spatially sampled information samples with regions of different sizes,
wherein the data stream comprises multi-tree subdivision information relating to the subdivision and inheritance information associated with an inheritance region including a set of leaf regions, wherein each of the leaf regions has associated therewith a size and is to be reconstructed based on one or more coding parameters,
wherein the multi-tree subdivision information is used to subdivide the array of information samples into a plurality of regions including the inheritance region, each of the plurality of regions being associated with one of a plurality of hierarchy levels associated with multi-tree subdivision of the array, and the inheritance information indicates a decision as to whether or not inheritance is to be used for sharing at least one coding parameter among the set of leaf regions based on the size of the leaf region within the inheritance region, wherein regions at different hierarchy levels of the plurality of hierarchy levels have different degrees of sharing of coding information via inheritance, and
if inheritance is indicated to be used, at least one syntax element associated with the inheritance region, the at least one syntax element representing a set of coding parameter including a coding parameter used in residual coding of the set of leaf regions to be shared among the set of leaf regions, without inserting corresponding at least one coding parameter of each of the set of leaf regions, which are decoded in a depth-first traversal order, wherein
the at least one syntax element is to be used, during decoding, to generate, for each of the set of leaf regions, a respective prediction signal based on the shared at least one syntax element inherited from the inheritance region, and each of the set of leaf regions is reconstructed based on the respective prediction signal.
24. The computer-readable medium according to claim 23 , wherein the data stream further comprises a residual for each of the set of leaf regions.
25. The computer-readable medium according to claim 23 , wherein the data stream further comprises at least one syntax element representing the coding parameters associated with each of the set of leaf regions when the inheritance region has its corresponding inheritance information indicating no use of inheritance.
26. The computer-readable medium according to claim 25 , wherein, if inheritance is indicated not to be used, the data stream comprises the coding parameters associated with each of the set of leaf regions.
27. The computer-readable medium according to claim 23 , wherein each of the set of leaf regions is reconstructed by prediction using a prediction mode determined based on the at least one syntax element.
28. The computer-readable medium according to claim 23 , wherein the at least one syntax element represents a coding parameter related to an interpolation filter used in coding the set of leaf regions.