Variable-Length Video Decoding Using Complete Binary Tree Lookup
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Solution Overview
Problem
Current video decoding methods using variable length codes are inefficient and time-consuming, particularly in handling high-data-rate video streams, due to the complexity of entropy coding and decoding processes.
Innovation Solution
A method for decoding complete binary tree codes and variable length codes is introduced, involving the calculation of TabIndex to efficiently extract indices from bitstreams, with specific procedures for coeffToken, totalZeros, and zeroLeft decoding, utilizing tables and leading zero detection to simplify the decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional variable length decoding methods are used, then decoding accuracy is maintained, but decoding speed and efficiency deteriorate
Solution Approach 1:
The patent pre-calculates and stores the relationship between TabIndex values and the number of bits to read in a lookup table during system initialization. This preliminary action eliminates the need for repeated log2 calculations and bit counting during actual decoding operations, significantly reducing decoding time while maintaining accuracy.
Solution Approach 2:
The patent creates a simplified copy of the decoding logic by pre-computing the bit consumption patterns for all possible TabIndex values and storing them in a lookup table. This copy allows the decoder to directly retrieve pre-computed values instead of performing complex calculations in real-time, thereby improving decoding speed without sacrificing precision.
2Measurement precision
If complex entropy decoding processes are used, then decoding accuracy is maintained, but computational complexity increases
Solution Approach 1:
The patent performs complex log2 calculations and bit pattern analysis in advance during table generation, storing only the results in a lookup table. This shifts computational complexity from the runtime decoding phase to the initialization phase, making the actual decoding process simple and fast while maintaining full decoding accuracy.
Solution Approach 2:
The patent replaces complex mechanical computation operations (log2 calculations, bit counting, conditional logic) with a simple table lookup operation. This substitution dramatically reduces computational complexity during decoding while preserving the accuracy of the original complex algorithm.
3Productivity
If standard variable length decoding is used, then compatibility with existing standards is maintained, but processing efficiency deteriorates
Solution Approach 1:
The patent creates an optimized copy of the standard decoding process by pre-computing the bit consumption patterns according to H.264/MPEG-4 standards and storing them in a lookup table. This copy maintains full compatibility with the standard while achieving superior processing efficiency through direct table lookup instead of repeated calculations.
Solution Approach 2:
The patent changes the parameter representation from raw TabIndex values requiring log2 calculations to pre-computed bit counts stored in a lookup table. This parameter transformation maintains compatibility with the standard's encoding scheme while dramatically improving processing efficiency during decoding operations.
Data Source
AI summary
The present invention is to provide a variable length decoding method for decoding complete binary tree code, which is implemented to an entropy coding module for executing the process comprising the steps of: procuring a TabIndex to calculate a value T=└log2(TabIndex)┘; reading T bits from a bitstream to obtain a first result M; determining whether or not the result M is smaller than (TabIndex-(1<<T)); if not, obtaining Index equal to (1<<T)−M−1; otherwise, reading 1 bits from the bitstream to obtain a second result N; and then obtaining Index equal to TabIndex-2×M−N−1, so as to decode data stream of video more efficiently and fast.