CPBRD Signaling for HRD-Compliant Video Bitstream Splicing
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Solution Overview
Problem
Existing video splicing methods face challenges in maintaining HRD compliance after concatenating bitstreams, leading to buffer overflow or underflow issues, as current CPBRD value signaling approaches are burdensome and do not guarantee compliance in spliced streams.
Innovation Solution
Innovative signaling of CPBRD values that allow for relative increment values based on preceding pictures, using single-value or two-value approaches with flags and delta values, enabling seamless splicing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing CPBRD value signaling approaches are used, then video bitstreams can be encoded and decoded, but splicing operations become burdensome and HRD compliance cannot be guaranteed in spliced streams
Solution Approach 1:
The patent applies preliminary action by pre-calculating and signaling CPBRD values at the time of encoding, taking into account potential future splicing operations. The encoder signals whether a picture is a splice point and provides appropriate CPBRD values that maintain HRD compliance even after splicing, eliminating the need for complex post-splicing adjustments and ensuring compliance is guaranteed from the outset.
2Reliability
If CPBRD values are adjusted to account for splicing, then HRD compliance may be maintained, but the operations become burdensome and difficult
Solution Approach 1:
The patent applies self-service by enabling the bitstream to carry all necessary information for maintaining HRD compliance through its own structure. The CPBRD values and splice point indicators are embedded in the bitstream during encoding, allowing the decoded video to self-maintain compliance without requiring complex external adjustment mechanisms or difficult post-processing operations.
3Adaptability or versatility
If two source streams are independently HRD-compliant, then each stream can be decoded properly, but the spliced stream is not guaranteed to be HRD-compliant
Solution Approach 1:
The patent applies feedback by incorporating splice point indicators and adjusted CPBRD values into the spliced bitstream that provide continuous information about buffer state transitions. This embedded feedback allows the decoder to automatically adjust its buffer management to maintain HRD compliance throughout the spliced stream, bridging the compliance gap that would otherwise exist between independently compliant source streams.
Data Source
AI summary
Innovations in syntax and semantics of coded picture buffer removal delay (“CPBRD”) values potentially simplify splicing operations. For example, a video encoder sets a CPBRD value for a current picture that indicates an increment value relative to a nominal coded picture buffer removal time of a preceding picture in decoding order, regardless of whether the preceding picture has a buffering period SEI message. The encoder can signal the CPBRD value according to a single-value approach in which a flag indicates how to interpret the CPBRD value, according to a two-value approach in which another CPBRD value (having a different interpretation) is also signaled, or according to a two-value approach that uses a flag and a delta value. A corresponding video decoder receives and parses the CPBRD value for the current picture. A splicing tool can perform simple concatenation operations to splice bitstreams using CPBRD value for the current picture.