SPS DPB Signaling for Consistent Video Buffer Configuration
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Solution Overview
Problem
The signalling of syntax elements in the sequence parameter set (SPS) for decoded picture buffer (DPB) information in video coding is inefficient and inconsistent, leading to potential inconsistencies in video reconstruction.
Innovation Solution
A method and apparatus for encoding and decoding video bitstreams that reliably signal DPB syntax elements by using flags to specify the presence and content of DPB parameters, ensuring efficient and consistent reconstruction of video sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DPB parameters syntax structure is always present in SPS, then video reconstruction consistency is improved, but bitstream overhead increases
Solution Approach 1:
The patent applies dynamics by making the DPB parameters syntax structure conditional rather than static. The structure is present only when sps_ptl_dpb_hrd_params_present_flag is set to 1, allowing the system to adapt between including or excluding the syntax structure based on whether hierarchical temporal sublayer structure is used, thereby optimizing bitstream overhead while maintaining necessary reliability
Solution Approach 2:
The patent applies local quality by selectively applying different syntax structures to different temporal sublayers. The DPB parameters syntax structure with max_dec_pic_buffering_minus1, max_num_reorder_pics, and max_latency_increase_plus1 is applied specifically to temporal sublayers except the highest one when the flag is set, rather than uniformly to all sublayers, optimizing both consistency and overhead
2Manufacturing precision
If multiple syntax elements are always signaled, then DPB configuration accuracy is improved, but coding efficiency deteriorates
Solution Approach 1:
The patent uses dynamics by conditionally signaling syntax elements based on the value of sps_ptl_dpb_hrd_params_present_flag. When the flag is 0, the syntax elements are not signaled and default values are used. When the flag is 1, the syntax elements are signaled with full precision. This dynamic approach maintains DPB configuration accuracy when needed while improving coding efficiency when default values suffice
Solution Approach 2:
The patent applies local quality by providing different levels of syntax element detail for different temporal sublayers. The max_dec_pic_buffering_minus1, max_num_reorder_pics, and max_latency_increase_plus1 elements are applied specifically to non-highest temporal sublayers, allowing precise configuration where needed while reducing overhead for other layers
Data Source
AI summary
Signalling of syntax elements in a sequence parameter set of a video bitstream is addressed. Particularly, it is provided a method of decoding a video bitstream wherein a sequence parameter set, SPS, is coded that contains syntax elements that apply to a video sequence, the method comprising obtaining a value of a first syntax element from the SPS used to specify whether a decoded picture buffer, DPB, parameters syntax structure is present in the SPS and obtaining a value of a second syntax element from the SPS, at least when determining that the value of the first syntax element specifies that the DPB parameters syntax structure is present in the SPS, used to specify the presence of a DPB syntax element in the DPB parameters syntax structure, wherein the DPB syntax element is applied to a temporal sublayer except for the highest temporal sublayer in the video sequence.