Entry Point Frames for Interlaced Video Random Access
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Solution Overview
Problem
Existing video compression and decompression techniques are limited in flexibility and efficiency, particularly in handling interlaced video frames, where the placement of sequence-layer syntax elements is restrictive and inflexible, and trick mode signaling and processing involve complex coordination between decoder and receiver-side components, leading to delays and reduced responsiveness.
Innovation Solution
The implementation of entry points and entry point segments in video streams allows for flexible encoding and decoding decisions, enabling random access and efficient trick mode processing by signaling coding type information at the frame level and using start codes to indicate the beginning of decoding without requiring preceding picture information, thereby improving compression efficiency and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If sequence-layer syntax elements are placed at the sequence level to apply to all pictures, then signaling overhead is reduced, but flexibility and adaptability for individual frames are lost
Solution Approach 1:
The patent divides the syntax element placement into multiple levels: sequence-layer syntax elements for global parameters, picture-layer syntax elements for frame-specific parameters, and slice-layer syntax elements for segment-specific parameters. This hierarchical segmentation allows each level to handle appropriate parameters, reducing overall signaling overhead while maintaining necessary flexibility at each level.
Solution Approach 2:
The patent introduces a new dimension of organization by adding picture-layer and slice-layer syntax elements between the sequence-layer and the actual video data. This creates a multi-dimensional syntax structure that enables flexible parameter specification at different granularities without proportionally increasing signaling overhead.
2Measurement precision
If trick mode processing requires complex coordination between decoder and receiver-side components, then processing accuracy is improved, but latency and responsiveness are reduced
Solution Approach 1:
The patent performs preliminary organization of video data into entry point segments with clearly defined start codes and syntax elements during encoding. This pre-structuring allows the decoder to quickly locate and process specific segments without requiring complex real-time coordination, significantly reducing latency while maintaining processing accuracy.
Solution Approach 2:
The patent divides the video stream into discrete entry point segments with clear boundaries marked by start codes. Each segment is self-contained with necessary syntax elements, allowing independent processing. This segmentation enables the decoder and receiver to operate with simpler coordination protocols, reducing latency in trick mode operations.
3Adaptability or versatility
If random access is enabled in video streams, then adaptability and responsiveness are improved, but compression efficiency is reduced due to additional syntax elements and start codes
Solution Approach 1:
The patent implements random access by segmenting the video stream into entry point segments separated by start codes. Each segment begins with a key frame and contains picture-layer syntax elements that define its structure. This segmentation enables random access to any segment without requiring the entire stream, while the hierarchical syntax structure minimizes the overhead added by these access points.
Solution Approach 2:
The patent designs the syntax element structure to serve multiple functions: picture-layer syntax elements not only define picture-specific parameters but also facilitate random access and trick mode operations. This multi-functionality reduces the need for separate dedicated syntax elements, thereby minimizing the impact on compression efficiency while enabling random access capability.
Data Source
AI summary
A decoder receives a field start code for an entry point key frame. The field start code indicates a second coded interlaced video field in the entry point key frame following a first coded interlaced video field in the entry point key frame and indicates a point to begin decoding of the second coded interlaced video field. The first coded interlaced video field is a predicted field, and the second coded interlaced video field is an intra-coded field. The decoder decodes the second field without decoding the first field. The field start code can be followed by a field header. The decoder can receive a frame header for the entry point key frame. The frame header may comprise a syntax element indicating a frame coding mode for the entry point key frame and/or a syntax element indicating field types for the first and second coded interlaced video fields.