Video Coefficient Coding with Limited CABAC and Transform Skipping
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently encoding and decoding video data due to inappropriate encoding schemes for blocks with and without orthogonal transform, leading to increased processing delay, complexity, and code amount.
Innovation Solution
An encoder and decoder that limit the total number of context adaptive coding processes and use Golomb-Rice coding to encode/decode coefficient information flags, skipping unnecessary processes and converting coefficients based on neighboring coefficients to reduce processing delay and code amount, regardless of orthogonal transform application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If different encoding schemes are used for blocks with and without orthogonal transform, then coding efficiency is improved, but processing delay and complexity increase
Solution Approach 1:
The patent merges the encoding schemes for blocks with and without orthogonal transform by using the same Golomb-Rice coding and coefficient information flag encoding for both cases. This unification eliminates the need for separate processing paths, thereby reducing processing delay and complexity while maintaining coding efficiency through adaptive CABAC process limiting.
2Measurement precision
If context adaptive coding processes are increased to improve encoding precision, then coding accuracy is improved, but processing delay increases
Solution Approach 1:
The patent dynamically adjusts the number of CABAC processes based on block characteristics and limits the total number of CABAC processes to a predetermined value. By changing the parameter of CABAC process count from unlimited to limited, the patent reduces processing delay while maintaining coding accuracy through selective application of context adaptive coding where it provides the most benefit.
3Measurement precision
If coefficient information flags are encoded for all coefficients, then coding precision is improved, but code amount increases
Solution Approach 1:
The patent extracts and encodes only the necessary coefficient information flags rather than encoding all coefficient information. By selectively encoding only those flags that provide the most significant coding precision improvement, the patent reduces the code amount while maintaining essential coding precision through Golomb-Rice coding for the extracted remainder values.
4Productivity
If orthogonal transform is applied to all blocks, then coding efficiency is improved, but processing complexity and code amount increase
Solution Approach 1:
The patent dynamically determines whether to apply orthogonal transform to each block based on block characteristics and coding conditions. Rather than applying orthogonal transform uniformly to all blocks, the system adapts the transform application decision to each block's specific properties, thereby maintaining coding efficiency while reducing processing complexity and code amount for blocks where transform is not beneficial.
Data Source
AI summary
An encoder including circuitry and memory coupled to the circuitry. In both of a first case where an orthogonal transform is performed and a second case where the orthogonal transform is skipped, when a number of CABAC processes is within an allowable range, the circuitry: encodes a plurality of coefficient information flags by CABAC; and encodes a remainder value of the coefficient; and when the number of CABAC processes is not within the allowable range, the circuitry: skips the encoding of the plurality of coefficient information flags, wherein in the first case, the circuitry: converts the coefficient to a second coefficient by using a poszero value that is determined using a plurality of surrounding coefficients; and encodes a value of the second coefficient, and wherein in the second case, the circuitry: encodes the value of the coefficient.