Nested Entropy Coding for Motion Vector Predictor Signaling
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Solution Overview
Problem
Existing video compression systems face challenges in achieving efficient data compression while preserving image quality, particularly due to high bit rates required for transmitting motion vector information, which can lead to decoding errors and inefficiencies.
Innovation Solution
A nested entropy encoding structure is employed to encode motion vectors, utilizing a plurality of VLC tables based on syntax elements to optimize coding efficiency and preserve spatial and temporal independence, reducing the need for trimming duplicate vectors and truncating code symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motion vectors are encoded using conventional methods, then image quality is preserved, but bit rate increases significantly leading to transmission inefficiency
Solution Approach 1:
The patent implements nested entropy encoding where multiple VLC tables are organized in a hierarchical structure. First-order VLC tables encode motion vector predictors, while second-order VLC tables encode differences between predictors and actual motion vectors. This nested structure allows progressive refinement of motion vector precision while maintaining efficient bit rate control, resolving the contradiction between image quality preservation and transmission efficiency.
2Productivity
If motion vector predictors are trimmed to reduce overhead, then coding efficiency improves, but error resilience decreases due to loss of candidate vectors
Solution Approach 1:
The patent dynamically adjusts the set of candidate motion vector predictors based on decoding context and error conditions. The entropy decoding apparatus maintains a pool of candidate predictors and selectively activates them based on syntax elements and decoding state. This dynamic adaptation allows the system to optimize coding efficiency when conditions permit while preserving error resilience by retaining alternative candidates for error recovery, thus resolving the contradiction between coding efficiency and error resilience.
3Quantity of substance
If duplicate motion vectors are removed to reduce redundancy, then data compression improves, but decoding complexity increases due to need for trimming operations
Solution Approach 1:
The patent performs preliminary organization of motion vector predictors during the encoding phase, where duplicate and redundant predictors are identified and structured in advance. The entropy encoding apparatus prepares multiple VLC tables with pre-processed candidate predictors, organizing them in a hierarchical structure that facilitates efficient decoding. This preliminary action reduces the computational burden during decoding by eliminating the need for complex real-time trimming operations, thus resolving the contradiction between data compression and decoding complexity.
Data Source
AI summary
Methods and systems for improving coding decoding efficiency of video by providing a syntax modeler, a buffer, and a decoder. The syntax modeler may associate a first sequence of symbols with syntax elements. The buffer may store tables, each represented by a symbol in the first sequence, and each used to associate a respective symbol in a second sequence of symbols with encoded data. The decoder decodes the data into a bitstream using the second sequence retrieved from a table.