Selective Film Grain Preservation in Video Encoding
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Solution Overview
Problem
Current video compression technologies face challenges in preserving film grain noise, as compressing it reduces coding efficiency and leads to undesirable artifacts like blurriness and banding, while methods like film grain synthesis are computationally costly and not decoder compliant.
Innovation Solution
A systematic approach that selectively preserves film grain in video encoding by using a localized approach, adjusting quantization and encoder decisions based on film grain visibility, and applying a perceptual model to optimize compression, ensuring decoder compliance and minimal computational overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If film grain noise is compressed using conventional video compression technologies, then bandwidth is reduced, but visual quality deteriorates with artifacts like blurriness and banding
Solution Approach 1:
The patent applies different quantization strategies to different regions of the video frame based on film grain visibility. Regions with high film grain visibility use coarser quantization to save bandwidth, while regions with low film grain visibility use finer quantization to preserve visual quality. This localized approach optimizes the trade-off between bandwidth efficiency and visual quality preservation.
Solution Approach 2:
The patent dynamically adjusts quantization parameters based on the measured film grain visibility in different regions. By changing the quantization parameter values adaptively, the system achieves better bandwidth efficiency in grain-dominated regions while maintaining visual quality in regions where grain is less prominent, thus resolving the contradiction between bandwidth reduction and visual quality preservation.
2Manufacturing precision
If film grain synthesis is used to preserve film grain during compression, then film grain aesthetics are maintained, but computational cost increases significantly
Solution Approach 1:
The patent extracts and analyzes the film grain component from the video signal separately, measuring its visibility in different regions. By isolating the film grain characteristics, the system can make informed decisions about compression without requiring full film grain synthesis, thereby reducing computational cost while still preserving film grain aesthetics where important.
Solution Approach 2:
Instead of applying full film grain synthesis across the entire video, the patent applies grain preservation selectively only in regions where film grain is visibly present and aesthetically important. This partial action approach maintains film grain aesthetics where needed while avoiding the high computational cost of processing the entire video frame with synthesis algorithms.
3Manufacturing precision
If film grain synthesis is used to preserve film grain, then visual quality is maintained, but decoder compliance is lost
Solution Approach 1:
The patent measures and characterizes the film grain properties from the original video signal, creating a simplified representation that can be preserved through conventional compression. This copying approach captures the essential film grain characteristics without requiring complex synthesis algorithms, ensuring that the preserved grain is compatible with standard decoders while maintaining visual fidelity.
Solution Approach 2:
The patent enables the encoding system to automatically measure and preserve film grain characteristics without requiring special decoder capabilities. By making the encoding process self-sufficient in capturing and preserving film grain information through standard compression tools, the system maintains broad decoder compatibility while still achieving film grain preservation.
Data Source
AI summary
Techniques for selectively preserving film grain for video encoding are described. In certain embodiments, a content delivery system and/or service determines one or more blocks of a frame to preserve film grain in the encoding in contrast to preserving the film grain in the encoding of all of the blocks of the frame.