Intra-Picture Block Vector Correction for Efficient Picture Coding
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Solution Overview
Problem
Existing picture coding and decoding techniques that rely solely on decoded samples in the neighbor of the coding/decoding target block result in poor prediction efficiency.
Innovation Solution
A device that derives block vector candidates from coding information, selects a block vector, and corrects the reference position to refer to an inside referenceable region, using decoded samples from the target picture for prediction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If only decoded samples in the neighbor of the coding/decoding target block are used for prediction, then the decoding process is simple, but the prediction efficiency is poor
Solution Approach 1:
The patent segments the reference sample selection into multiple sources: neighboring block samples and intra-block copy samples from within the same picture. This segmentation allows the system to overcome the limitation of using only neighboring samples while maintaining a structured, manageable decoding process.
Solution Approach 2:
The patent introduces a new dimension for reference sample selection by allowing intra-block copy prediction within the same picture, in addition to the traditional inter-block prediction from neighboring blocks. This dimensional expansion provides more reference options and improves prediction accuracy.
2Measurement precision
If block vector candidates are derived from coding information and reference positions are corrected to refer to inside referenceable region, then prediction accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary actions by deriving block vector candidates from coding information storage and pre-correcting reference positions to ensure they point to valid regions within the referenceable area. This preliminary processing prevents errors later in the prediction process and simplifies subsequent operations.
Solution Approach 2:
The patent introduces an intermediary reference position correction mechanism that acts as a mediator between the block vector candidates and the actual reference sample selection. This intermediary step ensures that reference positions are valid while maintaining a clear separation of concerns in the processing pipeline.
3Measurement precision
If intra block copy prediction is performed using decoded samples from the target picture, then prediction efficiency is improved, but memory access requirements increase
Solution Approach 1:
The patent merges the intra block copy prediction process with the existing inter prediction framework by using the same block vector candidate derivation and reference position correction mechanisms. This merging allows the system to utilize decoded samples from the target picture without creating a completely separate processing path, thereby managing memory access requirements more efficiently.
Data Source
AI summary
A picture coding device includes: a block vector candidate derivation unit that derives block vector candidates of a target block in a target picture from coding information stored in coding information storage memory; a selector that selects a selected block vector from the block vector candidates; and a reference position correction unit that performs a correction regarding a reference block to be referred to by the selected block vector so that a reference position of the reference block is to be corrected to refer to an inside of a referenceable region, in which a decoded sample in the target picture is acquired from decoded picture memory as a prediction value of the target block based on the reference position of the reference block.