Slice Header Byte Alignment to Prevent Start Code Confusion
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Solution Overview
Problem
Existing methods in video encoding and decoding systems face issues with misidentifying the start code of a video bitstream due to differences between the processing order and signaling order of syntax elements, leading to potential confusion and increased delay, especially when emulation prevention byte insertion is performed without proper alignment.
Innovation Solution
The method involves aligning slice headers to ensure byte alignment and inserting differential data at the end of the slice header before performing emulation prevention byte insertion, allowing simultaneous processing of slice data and header without creating start code confusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Emulation Prevention Byte insertion is performed on the slice header when syntax elements are generated in different order than signaled, then start code misidentification is prevented, but encoding delay increases due to inability to perform on-the-fly insertion
Solution Approach 1:
The patent divides the slice header into multiple segments or layers, allowing EPB insertion to be performed on specific segments independently. This segmentation enables the encoder to insert EPBs at safe positions without waiting for all syntax elements to be generated, thus reducing encoding delay while maintaining start code identification accuracy.
Solution Approach 2:
The patent performs preliminary EPB insertion on portions of the slice header that are available earlier in the encoding process. By inserting EPBs in advance on available data segments rather than waiting for complete header generation, the system reduces encoding delay while ensuring start codes are properly prevented.
2Productivity
If Emulation Prevention Byte insertion is performed on the slice header before syntax element generation is complete, then encoding delay is reduced through on-the-fly insertion, but start code confusion may occur at transition points
Solution Approach 1:
The patent applies different EPB insertion strategies to different local regions or segments of the slice header. Rather than applying a uniform approach to the entire header, the system identifies specific safe positions within local segments where EPB insertion can be performed without risking start code creation at transition points between syntax elements.
Solution Approach 2:
The patent introduces intermediary markers or boundary indicators that separate different syntax element groups within the slice header. These intermediaries help identify safe insertion points for EPBs, allowing on-the-fly insertion while preventing start code confusion at transition points between differently-ordered syntax elements.
3Adaptability or versatility
If the slice header is not byte aligned, then more flexible syntax element ordering is possible, but EPB insertion becomes more complex and error-prone
Solution Approach 1:
The patent implements dynamic byte alignment adjustment within the slice header structure. Rather than requiring fixed alignment, the system dynamically determines appropriate alignment positions based on the actual syntax element ordering and content, allowing flexible element ordering while maintaining manageable EPB insertion complexity through adaptive alignment strategies.
Data Source
AI summary
A method and a video processor for preventing start code confusion. The method includes aligning bytes of a slice header relating to slice data when the slice header is not byte aligned or inserting differential data at the end of the slice header before the slice data when the slice header is byte aligned, performing emulation prevention byte insertion on the slice header, and combine the slice header and the slice data after performing emulation prevention byte insertion.