Block Vector History Lists for IntraTMP Coding Efficiency
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Solution Overview
Problem
Existing video coding techniques face inefficiencies in the storage and utilization of block vectors, leading to reduced coding gains, inefficient memory usage, and reduced image quality, particularly in intra temporal motion vector prediction modes.
Innovation Solution
Storing block vectors for current blocks in a history list that includes non-neighboring blocks, deriving a candidate list based on these vectors, and using them for subsequent blocks in intra temporal motion vector prediction, along with techniques like clipping or rounding to reduce memory usage and improve prediction signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If block vectors are stored only in a history list for neighboring blocks, then memory usage is reduced, but coding efficiency deteriorates because non-neighboring blocks cannot provide prediction candidates
Solution Approach 1:
The history list is segmented into two distinct parts: a first history list storing block vectors from neighboring blocks, and a second history list storing block vectors from non-neighboring blocks. This segmentation allows the system to selectively manage memory resources while providing comprehensive prediction candidates for both intra-block copy and intra temporal motion vector prediction modes.
Solution Approach 2:
The patent extends the traditional spatial dimension of block vector storage by introducing a temporal dimension through the second history list. This allows block vectors from previously decoded non-neighboring blocks to be utilized for current block prediction, effectively adding a time-based dimension to the prediction process and improving coding efficiency without proportionally increasing memory usage.
2Manufacturing precision
If block vectors from non-neighboring blocks are included in the history list, then prediction signal quality improves, but memory bandwidth utilization increases
Solution Approach 1:
The patent introduces clipping and rounding operations as parameter transformation steps. Block vectors from non-neighboring blocks undergo clipping to constrain their magnitude within acceptable ranges and rounding to adjust precision. These parameter changes reduce the memory bandwidth required to transfer and process block vectors while maintaining sufficient prediction accuracy for high-quality reconstruction.
3Quantity of substance
If clipping and rounding operations are applied to block vectors, then memory usage and bandwidth are reduced, but prediction accuracy may deteriorate
Solution Approach 1:
The patent applies clipping and rounding operations selectively and partially. Clipping is applied only when block vector magnitudes exceed predefined thresholds, and rounding is applied with controlled precision levels. This partial application of transformation operations reduces memory usage and bandwidth consumption while maintaining prediction accuracy within acceptable ranges, avoiding excessive loss of information.
Data Source
AI summary
A method of encoding or decoding video data includes storing a block vector (BV) for a current block in a history BV list for encoding or decoding a subsequent block, wherein the current block is encoded or decoded in intra temporal motion vector prediction (IntraTMP) mode, and wherein the history BV list includes BVs for blocks that do not neighbor the subsequent block; deriving a candidate list of BVs for the subsequent block based on BVs from the history BV list that includes the BV for the current block; and encoding or decoding the subsequent block based on the candidate list of BVs.