Low Complexity DST-7 DCT-8 Video Transform Computation
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Solution Overview
Problem
Current methods for video compression, particularly for next-generation video content with high spatial resolution and frame rate, face challenges in reducing computation complexity for Discrete Sine Transform-7 (DST-7) and Discrete Cosine Transform-8 (DST-8), leading to high memory storage and processing demands.
Innovation Solution
A low-complexity computation algorithm is developed using the Cooley-Turkey and Rader algorithms for FFT computations, along with the Winograd FFT and Prime Factor FFT algorithms, to reduce the computational complexity of DST-7 and DCT-8 transforms, leveraging their relationships to achieve efficient processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DST-7 and DCT-8 transforms are applied for video compression, then coding efficiency is improved, but computation complexity increases
Solution Approach 1:
The patent applies parameter changes by utilizing the mathematical relationship between DST-7 and FFT, transforming the computation parameters from direct DST-7 matrix multiplication to FFT-based computation with modified input/output parameters. This allows achieving the same transform effect with reduced computational complexity by changing the computation approach rather than directly calculating DST-7 coefficients.
Solution Approach 2:
The patent substitutes the mechanical matrix multiplication system with an FFT-based computational system. Instead of directly performing complex matrix operations for DST-7 and DCT-8 transforms, the invention replaces it with FFT computations that leverage the relationship between sine/cosine transforms and Fourier transforms, significantly reducing the computational burden.
2Manufacturing precision
If next-generation video content with high spatial resolution and frame rate is processed, then video quality is improved, but memory storage and processing power requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the complex DST-7 and DCT-8 transform computation into smaller FFT operations. Instead of performing one large complex transform, the method segments the computation into multiple smaller FFT steps that can be processed more efficiently, reducing the overall memory and processing power requirements while maintaining high video quality.
Solution Approach 2:
The patent introduces FFT as an intermediary computational method between the original signal and the final transform coefficients. Rather than directly computing DST-7 or DCT-8 transforms which require significant resources, the invention uses FFT as an intermediate step that leverages the mathematical relationship between these transforms and Fourier transforms, thereby reducing the quantity of computational resources needed.
Data Source
AI summary
The present disclosure relates to a method for processing a video signal by using a linear relationship between transform types, comprising the steps of: determining a transform group on the basis of a prediction mode of a current block; parsing a transform combination index from a video signal, wherein the transform combination index indicates anyone of a plurality of transform combinations in the transform group; deriving a transform combination corresponding to the transform combination index, wherein the transform combination consists of a horizontal transform and a vertical transform, and includes DST-7 or DCT-8; performing inverse transform on the current block on the basis of the transform combination; and restoring the video signal by using the inverse transformed current block.