Intra-Prediction Smoothing Control for Video Coding
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Solution Overview
Problem
Current video coding standards face challenges in efficiently compressing screen content due to its sharp edges and textures, which can negatively impact intra-prediction compression efficiency, particularly in High Efficiency Video Coding (HEVC) and emerging standards like Versatile Video Coding (VVC).
Innovation Solution
The method involves signaling intra-prediction smoothing control parameters through a dedicated flag in a bitstream, allowing for the enabling or disabling of smoothing operations at a slice level, using a control parameter at the Sequence Parameter Set (SPS) level and another at the slice header level, to adapt intra-prediction processing to the content properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intra-prediction smoothing tools (such as four-tap subpixel intra interpolation filtering and PDPC) are applied to screen content, then prediction accuracy may improve, but compression efficiency deteriorates due to sharp edges and textures
Solution Approach 1:
The patent applies dynamics by making the smoothing tool activation state changeable based on content type. A flag in the bitstream allows the decoder to dynamically enable or disable the smoothing tool for different content types (screen content vs. other content), optimizing the balance between prediction accuracy and compression efficiency for each specific case
Solution Approach 2:
The patent changes the parameter of smoothing tool activation by introducing a controllable flag that can be set to different values (enabled/disabled). This parameter change allows the system to adapt the smoothing behavior to match the characteristics of the input content, preventing unnecessary smoothing on screen content with sharp edges while allowing it for content types that benefit from smoothing
2Device complexity
If smoothing operations are applied to all content uniformly, then processing simplicity is maintained, but compression efficiency is reduced for screen content with sharp edges
Solution Approach 1:
The patent applies local quality by differentiating the processing behavior based on content type identification. The system maintains simple uniform processing for most content while applying enhanced or disabled processing locally for screen content identified through the flag, optimizing compression efficiency for specific regions or content types without complicating the overall processing architecture
3Device complexity
If no smoothing control mechanism is provided, then bitstream complexity is minimized, but adaptability to different content properties is insufficient
Solution Approach 1:
The patent applies segmentation by dividing the control information into separate components: a flag element that indicates smoothing tool activation and separate content type identification mechanisms. This segmentation allows for flexible adaptability to different content properties while keeping the bitstream structure organized and manageable, avoiding unnecessary complexity by only including control elements when needed
Data Source
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AI summary
The present disclosure provides methods and devices of signaling intra predicting smoothing control parameters for encoding or decoding of video or image data. The method comprises: obtaining a first control parameter in a Sequence parameter set, SPS level, wherein a first value of the first control parameter in the SPS level indicates that smoothing is not applied for any block of a sequence, a second value of the first control parameter in the SPS level indicates that smoothing is applied for each block of the sequence, and the method further comprises: when the value of the first control parameter in the SPS level is equal to a predefined value, obtaining a second control parameter in a slice header, wherein a first value of the second control parameter in the slice header indicates that smoothing is applied for each block if the slice.