Sub-Picture ID Mapping in Video Decoding Bitstreams
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Solution Overview
Problem
Existing video signal processing methods lack efficiency in encoding and decoding video signals, particularly in handling sub-pictures and their boundaries, which affects overall coding performance.
Innovation Solution
A video signal processing method and device that includes decoding and encoding processes for sub-pictures, where the number of sub-pictures is considered, and specific syntax elements are used to determine boundary processing, loop filtering, and ID mapping, enhancing coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the second syntax element is always included in the SPS RBSP syntax, then the boundary processing information is complete, but the bitstream size increases and coding efficiency decreases
Solution Approach 1:
The patent extracts the second syntax element from the universal set of syntax elements and makes it conditionally present only when sub-picture division is actually used (first syntax element value >= 2). This removes unnecessary information from the bitstream when sub-pictures are not employed, reducing bitstream size while preserving boundary processing information when needed.
Solution Approach 2:
The patent makes the presence of the second syntax element dynamic rather than static. The syntax element is adaptively included or excluded based on the value of the first syntax element, allowing the bitstream structure to change according to the actual picture configuration requirements.
2Adaptability or versatility
If the SPS RBSP syntax includes all sub-picture related syntax elements, then the sub-picture handling is comprehensive, but the processing complexity increases
Solution Approach 1:
The patent applies local quality by making syntax element inclusion dependent on local conditions (whether sub-picture division is used). The second syntax element is included only in the specific local case where sub-picture boundaries need processing, rather than universally in all cases.
3Productivity
If conditional parsing of the second syntax element is implemented, then the bitstream efficiency improves, but the parsing logic complexity increases
Solution Approach 1:
The patent performs preliminary action by evaluating the first syntax element before attempting to parse the second syntax element. This conditional check is performed early in the parsing process, allowing the decoder to skip unnecessary parsing operations and reduce overall processing complexity.
Data Source
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AI summary
A video signal decoding device comprises: a processor, wherein the processor is configured to: obtain a first syntax element (subpics_present_flag) indicating whether information related to at least one sub-picture is present; obtain a second syntax element (sps_num_subpics_minus1) indicating a number of the at least one sub-picture; obtain a third syntax element (sps_subpic_id_mapping_explicitly_signalled_flag) indicating whether sub-picture ID mapping for the at least one sub-picture is explicitly signalled; when the third syntax element indicates that the sub-picture ID mapping for the at least one sub-picture is explicitly signalled, obtain a fourth syntax element (sps_subpic_id_mapping_present_flag) indicating whether the sub-picture ID mapping for the at least one sub-picture is signalled in a sequence parameter set, SPS, raw byte sequence payload, RBSP, syntax; obtain a fifth syntax element (sps_subpic_id_len_minus1) indicating a number of bits minus 1 used to represent a sixth syntax element (sps_subpic_id[i]), the sixth syntax element indicates a sub-picture ID value of an i-th subpicture among the at least one sub-picture obtained in SPS RBSP syntax; wherein when the first syntax element indicates that information related to the at least one sub-picture is present, the second syntax element, the third syntax element, the fourth syntax element, the fifth syntax element, and the sixth syntax element are obtained; obtain a seventh syntax element (pps_subpic_id_mapping_present_flag) indicating whether the sub-picture ID mapping for the at least one sub-picture is signalled in a picture parameter set, PPS, RBSP syntax; obtain an eighth syntax element (pps_num_subpics_minus1) indicating the number of the at least one sub-picture; obtain a nineth syntax element (pps_subpic_id_len_minus1) indicating a number of bits minus 1 used to represent a tenth syntax element (pps_subpic_id[i]), the tenth syntax element indicates the sub-picture ID value of the i-th subpicture among the at least one sub-picture obtained in PPS RBSP syntax; wherein when the seventh syntax element indicates that the sub-picture ID mapping for the at least one sub-picture is signalled in the PPS RBSP syntax, the eighth syntax element, the nineth syntax element, and the tenth syntax element are obtained; wherein when the third syntax element indicates that the sub-picture ID mapping for the at least one sub-picture is not explicitly signalled or the fourth syntax element indicates that the sub-picture ID mapping for the at least one sub-picture is signalled in the SPS RBSP syntax, the seventh syntax element indicates that the sub-picture ID mapping for the at least one-sub picture is not signalled in the PPS RBSP syntax; wherein when the third syntax element indicates that the sub-picture ID mapping for the at least one sub-picture is explicitly signalled and the fourth syntax element indicates that the sub-picture ID mapping for the at least one sub-picture is not signalled in the SPS RBSP syntax, the seventh syntax element indicates that the sub-picture ID mapping for the at least one-sub picture is signalled in the PPS RBSP syntax; wherein when the fourth syntax element indicates that the sub-picture ID mapping for the at least one sub-picture is signalled in the SPS RBSP syntax, obtain the sixth syntax element; and wherein when the seventh syntax element indicates that the sub-picture ID mapping for the at least one-sub picture is signalled in the PPS RBSP syntax, obtain the tenth syntax element.