Zero Coefficients Map for Adaptive Filter Signaling
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Solution Overview
Problem
Existing video coding techniques face inefficiencies in bitrate reduction and filter coefficient signaling, particularly in adaptive filtering processes, which impact coding efficiency and complexity.
Innovation Solution
The use of a zero coefficients map is introduced to indicate which filter coefficients should be extracted or included in the bitstream, allowing for more efficient coding by eliminating the need to signal zero values and optimizing filter coefficient signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If all filter coefficients are signaled in the bitstream, then the filter can be accurately reconstructed at the decoder, but the bitrate increases due to unnecessary transmission of zero coefficients
Solution Approach 1:
The patent extracts only the non-zero filter coefficients from the complete set of filter coefficients and transmits them in the bitstream. A zero coefficients map indicates which coefficients are zero, allowing the decoder to reconstruct the complete filter without receiving unnecessary zero values, thereby reducing bitrate while maintaining filter accuracy.
Solution Approach 2:
Instead of transmitting all coefficients and marking zeros, the patent inverts the approach by transmitting only non-zero coefficients and using a map to indicate zero positions. This inversion eliminates redundant data transmission while preserving complete filter information at the decoder.
2Manufacturing precision
If adaptive filtering is applied to improve picture quality, then the filtering effectiveness increases, but the processing complexity increases due to filter coefficient signaling and adaptation
Solution Approach 1:
The patent extracts and transmits only the necessary non-zero filter coefficients, reducing the amount of data that needs to be processed and stored. This extraction approach maintains filtering effectiveness while reducing the complexity of coefficient management and signaling in the encoding and decoding processes.
3Loss of information
If zero coefficients are explicitly signaled in the bitstream, then the complete filter information is preserved, but the coding efficiency decreases due to redundant data transmission
Solution Approach 1:
The patent removes redundant zero coefficient transmissions by extracting and transmitting only non-zero coefficients. The zero coefficients map preserves complete filter information by indicating which positions are zero, thereby maintaining information completeness while eliminating redundant data transmission to improve coding efficiency.
Solution Approach 2:
The patent discards the transmission of zero coefficients as redundant information, relying on the zero coefficients map to recover the complete filter structure at the decoder. This approach maintains full filter information while improving coding efficiency by eliminating unnecessary data.
Data Source
AI summary
The present disclosure relates to adaptive filtering, e.g. adaptive loop filtering, which may be used during encoding and decoding of video pictures. In particular, the present disclosure provides for determining a zero coefficients map, in which each bit indicates whether or not a respective filter coefficient of a supporting region is to be included into the bitstream for an adaptive filter. An indication of the zero coefficients map is included into the bitstream before at least one filter coefficient of the adaptive filter indicated by the zero coefficients map as to be included into the bitstream. The provision of a zero coefficients map enables an efficient signaling and allows for flexible filter shapes that are particularly suitable for the content at hand.