Video Frame Adaptive Offsetting for Coding Efficiency
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Solution Overview
Problem
Internal Bit Depth Increase (IBDI) methods, such as left shifting, lead to spreading of non-zero differences between consecutive spatial samples, emphasizing high frequencies and reducing coding efficiency in video frame encoding and decoding.
Innovation Solution
Adaptive offsetting of pixel values in video frames to de-emphasize high frequencies, using offsets based on the spatial neighborhood of pixels, which depend on the number of neighboring pixels with values larger than the pixel to be offset, applied before transformation and quantization during encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If left shifting is used to increase bit depth, then precision of transforms and reference frames is improved, but high frequencies are emphasized and coding efficiency is reduced
Solution Approach 1:
The patent applies different offsetting strategies to different spatial locations based on local characteristics. Specifically, it performs adaptive offsetting where the offset amount depends on the spatial neighborhood of each pixel and the number of neighboring pixels with larger values, creating locally adapted precision enhancement rather than uniform processing
Solution Approach 2:
The patent changes the parameter of bit depth representation by introducing adaptive offsets to pixel values. Instead of simply left-shifting all values uniformly, it modifies the parameter representation locally by adding offsets that depend on neighborhood statistics, thereby changing how precision is distributed across the image
2Measurement precision
If left shifting is used to increase bit depth, then reference frames buffer precision is improved, but high frequencies are emphasized and coding efficiency is reduced
Solution Approach 1:
The patent applies different offsetting strategies to different spatial locations based on local characteristics. Specifically, it performs adaptive offsetting where the offset amount depends on the spatial neighborhood of each pixel and the number of neighboring pixels with larger values, creating locally adapted precision enhancement rather than uniform processing
Solution Approach 2:
The patent changes the parameter of bit depth representation by introducing adaptive offsets to pixel values. Instead of simply left-shifting all values uniformly, it modifies the parameter representation locally by adding offsets that depend on neighborhood statistics, thereby changing how precision is distributed across the image
3Productivity
If adaptive offsetting is applied to de-emphasize high frequencies, then coding efficiency is improved, but bit stream size increases
Solution Approach 1:
The patent applies partial offsetting rather than full offsetting to all pixels. The offset is applied selectively based on neighborhood conditions, and the offset amount is constrained to be no larger than a maximum offset that depends on the number of bits by which bit depth is increased. This partial application reduces the overall data volume while maintaining the beneficial de-emphasis of high frequencies
Data Source
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AI summary
A method and a device are described for modifying a video frame for encoding or decoding wherein values of pixels of the video frame are represented an increased bit depth. The described method comprises using processing means for executing the step of offsetting the pixel values of increased bit depth with offsets, the offsets depending on a spatial neighbourhood of the pixel to-be-offset. Such local adaptive offsetting of pixel values de-emphasizes high frequencies in the transform domain artificially emphasized by the bit depth increase.