Encoder and Decoder LIC Processing to Reduce Inter Prediction Time
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Solution Overview
Problem
Conventional encoders and decoders require long processing times when both bi-directional optical flow (BIO) and local illumination compensation (LIC) modes are applied, leading to inefficiencies in processing time, especially for low-performance systems.
Innovation Solution
The encoder and decoder implement a local illumination compensation (LIC) process using a finally-derived motion vector, performing the correction process before applying any further corrections, thereby shortening the processing time and enhancing coding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If both bi-directional optical flow (BIO) and local illumination compensation (LIC) modes are applied, then coding accuracy is improved, but processing time increases significantly
Solution Approach 1:
The patent performs LIC parameter derivation using finally-derived motion vectors before applying further corrections or processing. By preparing and storing the LIC parameters in advance based on the final motion vectors, the system avoids re-computing these parameters later, thus reducing overall processing time while maintaining coding accuracy.
Solution Approach 2:
The patent divides the processing into distinct stages: first deriving motion vectors, then deriving LIC parameters based on those motion vectors, and finally applying corrections. This segmentation allows each stage to be optimized independently and enables parallel processing of different blocks, reducing total processing time while maintaining accuracy.
2Productivity
If LIC parameter derivation is performed early in the process, then subsequent processing can proceed faster, but coding accuracy may be compromised
Solution Approach 1:
The patent uses finally-derived motion vectors as feedback to derive LIC parameters. By waiting until the motion vectors are fully derived and refined before using them for LIC parameter derivation, the system ensures that the most accurate motion information is available, thereby maintaining coding accuracy while still enabling efficient subsequent processing.
3Measurement precision
If multiple correction processes are applied sequentially, then coding accuracy is improved, but processing time and system complexity increase
Solution Approach 1:
The patent combines the LIC correction process with the motion compensation process by deriving LIC parameters based on finally-derived motion vectors and applying corrections in an integrated manner. This merging reduces the number of separate correction passes needed, thereby reducing system complexity and processing time while maintaining coding accuracy through the coordinated application of both corrections.
Data Source
AI summary
An encoder that encodes a moving picture using an inter prediction process, and includes circuitry and memory coupled to the circuitry. In the inter prediction process, when performing a correction process which is a local illumination compensation (LIC) process for a prediction image, the circuitry, in operation; performs the correction process on a prediction image generated using a finally-derived motion vector that is finally derived in a stage before the correction process; and after the correction process, determines, as a final prediction image, the prediction image subjected to the correction process, without applying other correction process on the prediction image.