Transform Coefficient High Frequency Zeroing for Video Compression
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Solution Overview
Problem
Current image/video coding techniques face inefficiencies in compressing and transmitting high-resolution, high-quality images/videos, particularly in handling immersive media formats like VR and AR, due to increased data transmission and storage costs.
Innovation Solution
The method involves coding transform coefficients based on high frequency zeroing, where the position information of the last significant coefficient in a block is determined, and the maximum length of the codeword is derived from the size of the low frequency region, allowing for more efficient binarization and improved CABAC throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional image coding techniques are used for high-resolution images/videos, then image quality is maintained, but transmission cost and storage cost increase
Solution Approach 1:
The patent extracts and removes high-frequency transform coefficients that are less significant to human perception, keeping only the low-frequency coefficients that contribute most to image quality. This selective extraction reduces the quantity of data to be transmitted and stored while maintaining perceived image quality.
Solution Approach 2:
The patent applies different coding strategies to different frequency regions of the transform coefficients. Low-frequency coefficients are coded with higher precision to preserve important image features, while high-frequency coefficients are zeroed out or coded with lower precision, optimizing the balance between quality and data reduction.
2Productivity
If high frequency zeroing is applied to transform coefficients, then compression efficiency increases, but coding complexity increases
Solution Approach 1:
The patent performs high-frequency zeroing as a preliminary step before entropy coding of transform coefficients. By pre-zeroing the high-frequency coefficients, the patent simplifies subsequent coding operations and reduces the number of coefficients that need to be encoded, thereby improving compression efficiency while managing complexity through structured preprocessing.
3Ease of operation
If position information of last significant coefficient is coded with fixed maximum length, then coding simplicity is maintained, but coding efficiency decreases
Solution Approach 1:
The patent dynamically determines the maximum length of the prefix codeword based on the actual size of the low-frequency transform coefficient region. Instead of using a fixed maximum length for all blocks, the patent adapts the codeword length to the specific block size and frequency zeroing configuration, improving coding efficiency while maintaining reasonable simplicity through formula-based adaptation.
Data Source
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AI summary
An image decoding method performed by a decoding apparatus according to the present disclosure includes receiving a bitstream including residual information; deriving quantized transform coefficients for a current block based on the residual information included in the bitstream; deriving residual samples for the current block based on the quantized transform coefficients; and generating a reconstructed picture based on the residual samples for the current block.