Encoder Quantization Threshold Calculation for Skipped Transforms
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently processing increasing amounts of digital video data while optimizing coding efficiency, image quality, and reducing processing complexity, particularly when orthogonal transforms are skipped.
Innovation Solution
An encoder and decoder system that determines a quantization parameter threshold using discrete integer calculations, limiting the quantization parameter value to inhibit inefficient thresholds when orthogonal or inverse orthogonal transforms are skipped, thereby reducing coding complexity and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-precision quantization parameter threshold is used, then coding accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent changes the parameter representation by using fixed-point arithmetic with predetermined shift amounts instead of floating-point operations. This transforms the quantization parameter threshold calculation from high-precision but complex operations to lower-precision fixed-point operations that are computationally simpler while maintaining sufficient accuracy for video coding applications.
Solution Approach 2:
The patent employs simplified calculation methods using integer arithmetic and bit shifting operations that are computationally inexpensive and can be discarded after each calculation. These lightweight computational objects replace complex floating-point calculation structures, reducing processing complexity while delivering adequate precision for the application.
2Measurement precision
If complex calculation methods are used for quantization parameter determination, then coding precision is improved, but processing speed decreases
Solution Approach 1:
The patent substitutes complex mechanical-like floating-point calculation systems with simpler integer arithmetic and bit manipulation operations. This replacement uses fundamental processor instructions (addition, subtraction, bit shifting) that execute faster than floating-point operations, thereby improving processing speed while maintaining adequate calculation precision through fixed-point representation.
3Manufacturing precision
If high-precision quantization parameters are always used, then image quality is improved, but coding efficiency decreases
Solution Approach 1:
The patent introduces dynamic adaptation by adjusting the precision and calculation method based on the specific coding context. The quantization parameter threshold calculation uses fixed-point arithmetic with configurable shift amounts that can be adapted to different block types, prediction modes, and complexity settings, allowing the system to optimize between image quality and coding efficiency dynamically rather than using fixed high-precision methods always.
Data Source
AI summary
An encoder includes: circuitry; and memory coupled to the circuitry. In the encoder, in operation, the circuitry: performs calculation that involves multiplication and from which a plurality of discrete integers are yieldable as a calculation result, to derive one of the plurality of discrete integers as a quantization parameter threshold; and when orthogonal transform is skipped for a current block of an image, determines a quantization parameter value for the current block, using the quantization parameter threshold. The calculation involves multiplying a first value by a first fixed value, the first value and the first fixed value being each an integer. The first value is a limit value to be included in a header of a bitstream.