Intra Prediction Mode Search for Faster Image Encoding
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Solution Overview
Problem
Existing image encoding and decoding methods face challenges in efficiently determining intra prediction modes, leading to suboptimal compression and reconstruction of images.
Innovation Solution
The method involves obtaining and determining intra prediction modes for image blocks based on a search range, allowing for the generation of prediction blocks and reconstructed images using specific intra prediction modes, with the ability to split coding units into various shapes and sizes for improved encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a full search of all intra prediction modes is performed to find the optimal mode, then prediction accuracy is improved, but encoding complexity and time consumption increase significantly
Solution Approach 1:
The patent segments the intra prediction mode search space by dividing coding units into multiple sub-blocks and performing mode determination separately for each sub-block. This segmentation allows the encoder to focus computational resources on local optimal modes rather than performing a exhaustive search across the entire block, thereby reducing encoding complexity while maintaining prediction accuracy through localized optimization.
Solution Approach 2:
The patent applies local quality by determining different intra prediction modes for different sub-blocks within a coding unit based on local characteristics. Instead of applying a single mode to the entire block, the encoder evaluates and selects optimal modes for each sub-block independently, allowing prediction accuracy to be optimized locally while the overall encoding complexity is managed through the sub-block structure.
2Manufacturing precision
If more intra prediction modes are tested to improve reconstruction quality, then image quality is improved, but encoding time increases
Solution Approach 1:
The patent performs preliminary action by determining intra prediction modes for sub-blocks in a structured sequence before finalizing the complete coding unit reconstruction. The encoder establishes mode decisions for individual sub-blocks beforehand, which allows for optimized reconstruction quality to be achieved through systematic evaluation while managing encoding time through the pre-established sub-block processing framework.
3Ease of manufacture
If coding units are restricted to fixed shapes and sizes, then encoding simplicity is maintained, but adaptation to different image regions and features is reduced
Solution Approach 1:
The patent applies segmentation by dividing coding units into multiple sub-blocks that can be processed independently with potentially different prediction modes. This segmentation maintains the simplicity of fixed-size coding unit structures while enabling adaptability through the ability to apply different modes to different sub-blocks, allowing the encoder to adapt to local image characteristics without changing the fundamental coding unit structure.
Data Source
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AI summary
An image decoding method and apparatus, and an image encoding method and apparatus, are provided. The image decoding method includes obtaining information about a first intra prediction mode of a current block from a bitstream, determining the first intra prediction mode of the current block by using the information about the first intra prediction mode, determining a search range of a second intra prediction mode based on based on the first intra prediction mode, determining the second intra prediction mode for the current block within the search range of the second intra prediction mode, and generating a prediction block by performing intra prediction on the current block by using the second intra prediction mode, and generating a reconstructed image based on the prediction block.