Techniques for describing temporal coding structure
The disclosed subject matter describes a new pattern description that can be part of an SEI message or a parameter set, and can be used to describe a temporal picture coding structure and associated bitrates and frame rates. The knowledge of the coding structure can benefit transraters, bitstream extractors, and digital video recorders. Decoders can utilize the coding structure information for example, to decode pictures in parallel, using multiple threads/cores.
1. A method for video decoding in a decoder comprising:
decoding, from a coded video bitstream, a first coded picture of a first picture type other than Independent Decoder Refresh (IDR) picture, the first coded picture including a Supplementary Enhancement Information (SEI) message comprising a pattern description indicative of at least a prediction structure of a plurality of coded pictures including the first coded picture, the pattern description comprising:
at least one value num_pictures_in_sop_minus_1 indicative of the number of coded pictures represented in the pattern description, num_pictures_in_sop_minus_1 having a value larger than 0, and
a table of num_pictures_in_sop_minus_1+1 entries, each entry comprising a picture type (primary_pic_type), and a value indicative of a temporal layer (temporal_num) of a picture represented by the table entry, the table including at least a first entry and a second entry, the first entry associated with a picture picA and including a value primary_pic_type_A and a value temporal_num_A, the second entry associated with a picture picB and including a value primary_pic_type_B and a value temporal_num_B, primary_pic_type_A being different from primary_pic_type_B, picB can depend on picA only when temporal_num_A is less than or equal to temporal_num_B; and
decoding at least one n-th picture, where n is between 0 and num_pictures_in_sop_minus_1, the n-th picture being n pictures in the future of the first picture, and the n-th picture having a primary picture type and a temporal layer the same as the values primary_pic_type and temporal_num, respectively, in the n-th entry of the table.
2. The method of claim 1 , further comprising:
decoding in parallel at least two of the num_pictures_in_sop_minus_1 pictures based on independency of the two pictures, the independency of the two coded pictures being derived from the decoded pattern description, and
the two coded pictures being predictively coded.
3. A method for video decoding in a decoder comprising:
decoding, from a coded video bitstream, a first coded picture of a first picture type other than Independent Decoder Refresh (IDR) picture, the first coded picture including a Supplementary Enhancement Information (SEI) message comprising a pattern description indicative of at least a prediction structure of a plurality of coded pictures including the first coded picture, the pattern description comprising:
at least one value num_pictures_in_sop_minus_1 indicative of the number of coded pictures represented in the pattern description, num_pictures_in_sop_minus_1 having a value larger than 0, and
a table of num_pictures_in_sop_minus_1+1 entries, each entry comprising a picture type (primary_pic_type), and a value indicative of a temporal layer (temporal_num) of a picture represented by the table entry, the table including at least a first entry and a second entry, the first entry associated with a picture picA and including a value primary_pic_type_A and a value temporal_num_A, the second entry associated with a picture picB and including a value primary_pic_type_B and a value temporal_num_B, primary_pic_type_A being different from primary_pic_type_B, picB can depend on picA only when temporal_num_A is less than or equal to temporal_num_B; and
decoding at least one n-th picture, where n is between 0 and num_pictures_in_sop_minus_1, the n-th picture being n pictures in the future of the first picture, and the n-th picture having a primary picture type and a temporal layer of the n-th decoded coded picture is the same as the values primary_pic_type and temporal_num, respectively, in the n-th entry of the table.
4. The method of claim 3 , further comprising:
decoding in parallel at least two of the num_pictures_in_sop_minus_1 pictures based on independency of the two pictures, the independency of the two coded pictures being derived from the decoded pattern description.
5. A non-transitory computer readable medium comprising executable instructions to direct a processor to perform the method of claim 1 .
6. A non-transitory computer readable medium comprising executable instructions to direct a processor to perform the method of claim 3 .