Video Encoding Group Segmentation for Codec Delay Reduction
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Solution Overview
Problem
Conventional video image encoding technologies face challenges in reducing codec delay to less than the processing time for one picture, leading to disproportionate encoding amounts and image quality deterioration, with existing methods struggling to achieve instantaneous decoding and display without buffer underflow or overflow.
Innovation Solution
A video image encoding device that divides pictures into groups, determines the group configuration, adds group information to the output stream, calculates output times, and controls the encode amount to ensure data arrival at the decoding buffer, allowing for controlled output delays and reduced codec delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the buffer size is reduced to decrease buffer delay and codec delay, then the delay from picture input to display is reduced, but the degree of freedom in allocating encoding amount decreases, leading to image quality deterioration
Solution Approach 1:
The patent divides a picture into multiple groups (e.g., slices or block groups) and processes each group independently with its own decoding time calculation. This segmentation allows the system to reduce overall codec delay by enabling parallel processing and earlier display of individual groups, while maintaining sufficient encoding flexibility through group-level control parameters.
2Loss of time
If the buffer size is reduced to decrease buffer delay, then the delay is reduced, but the degree of freedom in allocating encoding amount for each picture decreases
Solution Approach 1:
The patent implements dynamic encoding amount control at the group level, where the encoding amount for each group is adjusted based on real-time buffer status and decoding requirements. This dynamic approach maintains adaptability in encoding allocation while working within smaller buffer constraints, allowing the system to respond flexibly to varying content complexity and buffer conditions.
3Productivity
If instantaneous decoding is assumed with zero processing time, then the decode time equals input time plus fixed delay, but actual decoding takes non-zero time, causing receiving buffer underflow
Solution Approach 1:
The patent calculates and prepares decoding time information in advance for each group, including the actual non-zero decoding time requirements. By pre-computing when each group will be ready for display and accounting for decoding processing time, the system ensures that data arrives at the receiving buffer with sufficient time margin, preventing underflow while maintaining high decoding speed.
4Productivity
If encoding amount varies disproportionately within the same sequence or picture, then the transmission rate becomes non-constant, but buffers are required to maintain constant transmission rate
Solution Approach 1:
The patent segments the picture into multiple groups that can be encoded and transmitted with different encoding amounts based on local complexity. Each group is independently controlled with its own encoding parameters and timing information, allowing variable encoding efficiency across different regions while maintaining overall constant transmission rate through proper scheduling and buffer management.
Data Source
AI summary
A method includes determining a group to which each of a plurality of blocks belongs, the plurality of blocks being obtained by dividing each picture included in video image data; adding, to an output stream, group information expressing the group to which each of the plurality of blocks belongs; calculating an output time for each of the groups; determining output delay for each of the groups; adding, to the output stream, an output delay time from a decode time of each of the groups; controlling an encode amount so that data used for outputting all of the blocks included in one of the groups arrives at a decoding buffer of a decoding device and decoding is completed by an output time expressed by the output delay time; and performing encoding based on the encode amount that has been controlled.