HEVC CABAC Coefficient Coding With Golomb-Rice and EG Switching
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Solution Overview
Problem
High bit-rate encoding and decoding in video coding standards like HEVC using CABAC face significant throughput performance issues, consuming substantial processing resources and time, especially with high bit-rate cases and large Absolute-3 values.
Innovation Solution
Implementing a method that involves arithmetic decoding and encoding of transform coefficients using k-th order Exp-Golomb coding, and dynamically switching between Golomb-Rice and truncated Exp-Golomb coding based on Absolute-3 value thresholds to optimize processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If CABAC is used to compress transform coefficients without loss, then compression efficiency is improved, but processing time and resource consumption increase significantly
Solution Approach 1:
The patent segments the transform coefficient encoding process into multiple stages: significance map encoding, level value encoding, and bypass encoding. By dividing the complex CABAC process into smaller manageable segments with different encoding strategies, the processing time is reduced while maintaining compression efficiency.
Solution Approach 2:
The patent dynamically adjusts the encoding method based on the absolute value of transform coefficients. For coefficients with small absolute values, Golomb-Rice coding is used; for larger values, truncated Exp-Golomb coding is applied. This dynamic adaptation optimizes the balance between compression efficiency and processing speed.
2Manufacturing precision
If high bit-rate encoding is performed with large Absolute-3 values, then encoding precision is improved, but throughput performance deteriorates
Solution Approach 1:
The patent changes the encoding parameters (coding method selection) based on the absolute value threshold of transform coefficients. By switching between Golomb-Rice and truncated Exp-Golomb coding methods according to coefficient magnitude, the system maintains encoding precision for large values while improving throughput overall.
Solution Approach 2:
The patent applies full CABAC processing only when necessary (for significant coefficients), while using simpler encoding methods for less critical data. This partial application of complex processing maintains precision where needed while improving overall throughput by avoiding unnecessary complex operations.
3Productivity
If Golomb-Rice coding is used for transform coefficients, then processing speed is improved, but compression efficiency decreases for large values
Solution Approach 1:
The patent dynamically selects the coding method based on the absolute value of transform coefficients. Golomb-Rice coding is used for small values where it provides good speed, while truncated Exp-Golomb coding is used for large values where it provides better compression efficiency. This dynamic selection optimizes both speed and compression.
Solution Approach 2:
Different coding methods are applied to different ranges of coefficient values based on their local characteristics. Small coefficients use Golomb-Rice coding optimized for their distribution, while large coefficients use truncated Exp-Golomb coding optimized for their magnitude, achieving local optimization throughout the coefficient range.
Data Source
AI summary
A system utilizing a high throughput coding mode for CABAC in HEVC is described. The system may include an electronic device configured to obtain a block of data to be encoded using an arithmetic based encoder; to generate a sequence of syntax elements using the obtained block; to compare an Absolute-3 value of the sequence or a parameter associated with the Absolute-3 value to a preset value; and to convert the Absolute-3 value to a codeword using a first code or a second code that is different than the first code, according to a result of the comparison.