Video Coding Quantization Parameter Prediction for Transcoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding technologies, such as HEVC, face challenges in transcoding between sequential and parallel modes, especially when the quantization parameter varies across blocks, leading to inefficiencies in compression and decoding processes.
Innovation Solution
A method and device for coding and decoding that allows error-free transcoding between sequential and parallel block sets by predicting quantization parameter values from the last sub-block of the previous line, enabling efficient statistical learning and improved prediction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If sequential coding mode is used with variable quantization parameters, then compression performance is improved, but transcoding to parallel mode becomes complex and error-prone
Solution Approach 1:
The patent applies preliminary action by pre-defining the quantization parameter for the first block of each line based on the last block of the previous line during the encoding phase. This advance preparation eliminates the need for complex runtime calculations during transcoding, allowing seamless conversion between sequential and parallel modes while maintaining compression efficiency.
2Productivity
If parallel processing is implemented, then processing speed is improved, but prediction efficiency decreases due to loss of statistical learning
Solution Approach 1:
The patent implements feedback by using the quantization parameter from the last processed block as the basis for determining the quantization parameter of the first block in the next line. This creates a statistical learning mechanism that maintains prediction efficiency even in parallel processing mode, as each line benefits from the statistical information of the previous line.
3Adaptability or versatility
If quantization parameter varies across blocks, then compression adaptability is improved, but waiting time for parameter determination increases
Solution Approach 1:
The patent eliminates waiting time by pre-determining the quantization parameter for the first block of each line during the encoding process. Instead of calculating it in real-time during decoding or transcoding, the value is prepared in advance, allowing immediate use without introducing any delay to the processing pipeline.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A method of coding an image comprising the steps of partitioning (C1, C2) the image into a plurality of blocks (CTU1, CTU2, …, CTUi,…, CTUS) able to contain symbols belonging to a predetermined set of symbols, of entropy coding of a current block on the basis of at least one probability of symbol occurrence and of predictive coding of a compression parameter (QP) associated with said current block. In the case where the current block is the first block to be coded of a considered set of consecutive blocks to be coded, the following steps are carried out: determination (C40a)), during said step of entropy coding, of probabilities of symbol occurrence for said first current block, based on the probabilities determined on completion of the coding and decoding of the last block of another set of blocks immediately preceding said considered set in the order of coding of the blocks; and assignment (C41a)), during said predictive coding step, of a compression parameter prediction value which is independent of the compression parameter value associated with said last block.