Hypothetical reference decoder for scalable video coding
View Patent ↗The present principles relate to a hypothetical reference decoder (HRD) for a Scalable Video Coding extension for a compression algorithm. One such implementation proposes to modify the H.264/AVC HRD for use with the SVC of AVC. That implementation defines HRD constraints for each interoperability point of SVC. One implementation in particular is described, but other implementations are possible and are contemplated by the present principles. The changes for spatial, temporal, and SNR scalability are shown. There are also changes to the related HRD parameters followed that are shown. The several mentioned implementations provide rules for an HRD for SVC. At least one implementation proposes the SVC-HRD rules as modifications to the AVC-HRD rules. A user may use the proposed SVC-HRD rules to build an SVC-HRD and test a bitstream for SVC compliance.
1. A method for implementation of a hypothetical reference decoder (HRD) for scalable video coding (SVC), comprising:
determining values of variables included in a bit stream indicating a dependency layer, temporal layer, and quality layer of a scalable layer i, i being an integer; and
determining HRD parameters corresponding to said scalable layer i, the determined HRD parameters including at least one bit rate parameter, wherein the bit rate parameter is determined based on bits for the scalable layer i and its dependent layers, wherein the determined HRD parameters further include initial coded picture buffer (CPB) removal delay, initial coded picture buffer removal delay offset, CPB removal delay, and decoded picture buffer (DPB) output delay, wherein the determining HRD parameters comprises:
determining the CPB removal delay and the DPB output delay by using explicitly signaled parameters from a picture timing SEI message in the bit stream for each temporal layer, wherein the picture timing SEI message also indicates the number of temporal layers in the bit stream, and
determining the CPB removal delay and the DPB output delay to be the same for scalable layers corresponding to different spatial layers or quality layers at each temporal layer.
2. The method of claim 1 , in which there are multiple interoperability points in the bit stream, and the multiple interoperability points exhibit scalability with respect to each other.
3. The method of claim 2 , in which the exhibited scalability includes one or more of spatial scalability, temporal scalability, and SNR scalability.
4. The method of claim 1 which is defined by a set of rules for creating the hypothetical reference decoder.
5. The method of claim 1 , wherein values of the CPB removal delay and DPB output delay are kept same for scalable layers corresponding to different spatial layers and quality layers at each temporal layer, and wherein the values of the CPB removal delay and DPB output delay are different for each temporal layer.
6. A method for scalable video coding, comprising:
determining values of variables indicating a dependency layer, temporal layer, and quality layer of a scalable layer i, i being an integer;
determining hypothetical reference decoder (HRD) parameters corresponding to said scalable layer i, the determined HRD parameters including at least one bit rate parameter, wherein the bit rate parameter is determined based on bits for the scalable layer i and its dependent layers, wherein the determined HRD parameters further include initial coded picture buffer (CPB) removal delay, initial coded picture buffer removal delay offset, CPB removal delay, and decoded picture buffer (DPB) output delay; and
generating a bit stream including the determined values of variables and determined HRD parameters, wherein the CPB removal delay and the DPB output delay are only explicitly signaled in a picture timing SEI message in the bit stream for each temporal layer, the picture timing SEI message also indicating the number of temporal layers in the bit stream, and
wherein the CPB removal delay and the DPB output delay are determined to be the same for scalable layers corresponding to different spatial layers or quality layers at each temporal layer.
7. The method of claim 6 , in which there are multiple interoperability points in the bit stream, and the multiple interoperability points exhibit scalability with respect to each other.
8. The method of claim 7 , in which the exhibited scalability includes one or more of spatial scalability, temporal scalability, and SNR scalability.
9. The method of claim 6 , wherein values of the CPB removal delay and the DPB output delay are kept same for scalable layers corresponding to different spatial layers and quality layers at each temporal layer, and wherein the values of the CPB removal delay and the DPB output delay are different for each temporal layer.
10. A non-transitory storage medium having stored thereon instructions for causing one or more processors to perform:
determining values of variables included in a bit stream indicating a dependency layer, temporal layer, and quality layer of a scalable layer i, i being an integer; and
determining hypothetical reference decoder (HRD) parameters corresponding to said scalable layer i, the determined HRD parameters including at least one bit rate parameter, wherein the bit rate parameter is determined based on bits for the scalable layer i and its dependent layers, wherein the determined HRD parameters further include initial coded picture buffer (CPB) removal delay, initial coded picture buffer removal delay offset, CPB removal delay, and decoded picture buffer (DPB) output delay, wherein the determining HRD parameters comprises:
determining the CPB removal delay and the DPB output delay by using explicitly signaled parameters from a picture timing SEI message in the bit stream for each temporal layer, wherein the picture timing SEI message also indicates the number of temporal layers in the bit stream, and
determining the CPB removal delay and the DPB output delay to be the same for scalable layers corresponding to different spatial layers or quality layers at each temporal layer.
11. A non-transitory storage medium having stored thereon instructions for causing one or more processors to perform:
determining values of variables indicating a dependency layer, temporal layer, and quality layer of a scalable layer i, i being an integer;
determining hypothetical reference decoder (HRD) parameters corresponding to said scalable layer i, the determined HRD parameters including at least one bit rate parameter, wherein the bit rate parameter is determined based on bits for the scalable layer i and its dependent layers, wherein the determined HRD parameters further include initial coded picture buffer (CPB) removal delay, initial coded picture buffer removal delay offset, CPB removal delay, and decoded picture buffer (DPB) output delay; and
generating a bit stream including the determined values of variables and determined HRD parameters, wherein the CPB removal delay and the DPB output delay are only explicitly signaled in a picture timing SEI message in the bit stream for each temporal layer, the picture timing SEI message also indicating the number of temporal layers in the bit stream, and
wherein the CPB removal delay and the DPB output delay are determined to be the same for scalable layers corresponding to different spatial layers or quality layers at each temporal layer.