IntraBC Prediction Restriction for Video Coding Bandwidth Control
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Solution Overview
Problem
The High Efficiency Video Coding (HEVC) standard faces increased worst-case memory bandwidth issues due to Intra Block Copy (IntraBC) prediction, particularly in certain block sizes and prediction types, which can lead to higher memory bandwidth requirements.
Innovation Solution
The proposed solution restricts IntraBC prediction from using samples in specific block sizes or prediction types, or disables certain prediction units and types to reduce memory bandwidth, allowing exceptions based on motion vector conditions, thereby controlling bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IntraBC prediction is used with all block sizes and prediction types, then coding efficiency is improved, but worst-case memory bandwidth requirements increase
Solution Approach 1:
The patent applies local quality by differentiating treatment across different block sizes and prediction types. Specifically, it restricts IntraBC prediction for certain block sizes (e.g., 8x8, 4x4) and prediction types (e.g., planar, angular) while allowing it for others. This selective approach maintains coding efficiency where beneficial while reducing memory bandwidth consumption where less critical, thus resolving the contradiction between overall coding efficiency and peak memory bandwidth requirements.
Solution Approach 2:
The patent changes the parameter of block size and prediction type availability for IntraBC mode. By dynamically enabling or disabling IntraBC prediction based on specific block size and prediction type parameters, the system optimizes the balance between coding efficiency and memory bandwidth usage. This parameter-based control allows the encoder to adapt to different content characteristics while staying within memory bandwidth constraints.
2Quantity of substance
If IntraBC prediction is restricted for certain block sizes and prediction types, then memory bandwidth requirements are reduced, but coding efficiency may be compromised
Solution Approach 1:
The patent applies local quality by differentiating treatment across different block sizes and prediction types. Specifically, it restricts IntraBC prediction for certain block sizes (e.g., 8x8, 4x4) and prediction types (e.g., planar, angular) while allowing it for others. This selective approach maintains coding efficiency where beneficial while reducing memory bandwidth consumption where less critical, thus resolving the contradiction between overall coding efficiency and peak memory bandwidth requirements.
Solution Approach 2:
The patent applies partial action by implementing IntraBC prediction restriction only for specific block sizes and prediction types rather than universally. This partial application allows the system to achieve memory bandwidth reduction while preserving coding efficiency benefits for the block sizes and prediction types where IntraBC is most effective, thus balancing the trade-off between memory bandwidth and coding efficiency.
3Adaptability or versatility
If all prediction units are enabled for IntraBC mode, then coding flexibility is maintained, but worst-case bandwidth increases
Solution Approach 1:
The patent applies local quality by applying different IntraBC availability rules to different prediction unit sizes and types. For example, it may enable IntraBC for larger PUs (e.g., 16x16, 32x32) while restricting it for smaller PUs (e.g., 8x8, 4x4). This localized differentiation maintains coding flexibility for complex regions while reducing bandwidth requirements for simpler regions, resolving the contradiction between adaptability and bandwidth consumption.
Solution Approach 2:
The patent applies segmentation by dividing the prediction unit space into different categories based on size and type, and applying different IntraBC availability rules to each segment. This segmentation allows the system to optimize bandwidth usage for each category while maintaining overall coding flexibility, as each segment can be independently controlled based on its specific characteristics and bandwidth requirements.
Data Source
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AI summary
A method and apparatus of video coding using IntraBC (Intra Block Copy) for video data are disclosed. Restricted prediction is determined, in which one or more selected PU (prediction unit) sizes, PU prediction types or both are disabled or disallowed. Video coding is applied to the current block using coding modes including IntraBC prediction in accordance with the restricted prediction. The selected PU sizes, PU prediction types or both may correspond to 8x8 bi-prediction PU. In one example, the selected PU sizes, PU prediction types or both are disabled or disallowed for the restricted prediction except one or more conditions are determined to be satisfied. The conditions may correspond to at least one of two motion vectors of the 8x8 bi-prediction PU having integer values, the conditions may also correspond to at least one of motion vector components of the 8x8 bi-prediction PU having integer valueIntraBCIntraBCIntraBCIntraBCIntraBC.