Video Coding Quantization Prediction for Tree-Block Bit Reduction
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Solution Overview
Problem
Existing quantization parameter control methods in digital moving picture coding, such as MPEG-2 and AVC, result in increased code amounts due to differences in quantization parameters between adjacent blocks, especially when using hierarchical tree coding, leading to inefficient coding efficiency.
Innovation Solution
A moving picture coding and decoding method that partitions pictures into tree blocks, using quantization groups for parameter prediction, where the predictive quantization parameter is derived from adjacent blocks within the tree structure, adjusting for positions beyond boundaries to optimize coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If quantization parameter prediction uses the left block uniformly, then the prediction process is simple, but the code amount increases when block features differ
Solution Approach 1:
The patent applies different prediction strategies based on the local characteristics of blocks. When the left block and current block have similar features (same tree block), it uses the left block for prediction. When they differ (different tree blocks), it uses the previously coded block instead. This local adaptation reduces code amount while maintaining prediction accuracy.
2Measurement precision
If quantization parameter prediction uses the top block, then spatial adjacency is exploited, but processing turns are away from each other reducing prediction accuracy
Solution Approach 1:
The patent incorporates feedback from the coding process by using the previously coded block (in coding order) as a prediction reference when the top block is not suitable. This ensures that the prediction is based on blocks that have already been processed and have similar quantization parameters, improving both accuracy and efficiency.
3Manufacturing precision
If block size is reduced, then coding precision is improved, but processing turns become separated reducing prediction effectiveness
Solution Approach 1:
The patent dynamically selects the prediction reference block based on the current coding context and block position. The prediction strategy adapts to different block sizes and coding orders by choosing between the left block, top block, or previously coded block, ensuring effectiveness across various block dimensions.
Data Source
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AI summary
Provided is a video coding device with which each picture of a video is partitioned into a first block at a prescribed size which is further partitioned into one or a plurality of second blocks, and the video coded in block units. A quantization parameter computation unit (110) computes a second block quantization parameter. A predict quantization parameter derivation unit (114) derives a second block predict quantization parameter, using a quantization parameter of a third block which is adjacent to the left of the second block and a fourth block which is adjacent above the second block. A differential quantization parameter generating unit (111) generates a second block differential quantization parameter from the difference of the second block quantization parameter and the predict quantization parameter. A first coding bit string generating unit (112) codes the second block differential quantization parameter.