Video Quantization Masking Windows Around Scene Changes
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Solution Overview
Problem
Existing video compression techniques face challenges in reducing bitrate for high-resolution video content without compromising perceived quality and maintaining reasonable computational complexity.
Innovation Solution
Implementing a joint backward and forward temporal masking technique that dynamically adjusts quantization values based on the proximity to scene cuts, using masking windows with higher quantization values near scene cuts to minimize perceptible artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If video compression techniques are applied to reduce bandwidth, then bitrate is reduced, but computational complexity increases
Solution Approach 1:
The patent applies different quantization values to different temporal regions of the video stream. Specifically, frames near scene changes are encoded with higher quantization values (lower quality) while frames away from scene changes use lower quantization values (higher quality). This local differentiation allows bitrate reduction without uniformly degrading all video content, thereby reducing overall computational complexity while maintaining acceptable quality.
Solution Approach 2:
The patent dynamically adjusts the quantization parameter based on the temporal distance from scene changes. By changing the quantization parameter according to the position of frames relative to scene cuts, the system optimizes the balance between bitrate and quality. This parameter adaptation enables efficient compression that reduces computational load compared to applying high-quality encoding throughout the entire video.
2Productivity
If higher quantization values are used to reduce bitrate, then compression efficiency improves, but visual quality deteriorates
Solution Approach 1:
The patent implements local quality by applying higher quantization values specifically to frames near scene changes where the human visual system is less sensitive to artifacts. Frames away from scene changes maintain lower quantization values for better quality. This localized approach maximizes compression efficiency without uniformly sacrificing visual quality across the entire video stream.
Solution Approach 2:
The patent exploits the fact that scene changes create temporal masking effects in human vision, where artifacts near scene cuts become less noticeable. This harmful effect of the visual system (inability to detect artifacts near scene changes) is converted into a benefit for compression, allowing higher quantization values to be applied in those regions without perceptible quality loss, thus improving overall compression efficiency.
3Loss of energy
If frame removal is performed to reduce bandwidth, then bitrate decreases, but perceptible artifacts increase
Solution Approach 1:
The patent converts the harmful temporal masking effect of scene changes into a beneficial compression opportunity. By applying higher quantization values to frames near scene cuts, the system can remove or degrade frames in those regions without creating perceptible artifacts, since the human visual system cannot detect them. This reduces bitrate while maintaining acceptable perceived quality.
Solution Approach 2:
The patent changes the quantization parameter dynamically based on temporal position relative to scene changes. Frames closer to scene changes use higher quantization values that allow frame removal without noticeable artifacts, while frames farther from scene changes use lower quantization values that preserve quality. This parameter adaptation enables bitrate reduction without unacceptable artifact visibility.
Data Source
AI summary
A first quantization value for encoding at least one frame of a content item may be determined based at least on a predetermined bitrate and a point in the content item associated with a scene change. A first duration associated with a first portion of the content item may be determined. The first portion of the content item may comprise the at least one frame and may be associated with the first quantization value. A second quantization value for encoding at least another frame of the content item may be determined based at least on the predetermined bitrate. A second duration associated with a second portion of the content item may be determined. The second portion of the content item may comprise the at least another frame and may be associated with the second quantization value.