Multichannel Audio Encoding With Selective Subband Reverb Gains
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Solution Overview
Problem
Existing multi-channel audio encoding methods require a large number of bits to encode reverberation gain parameters for each subband, leading to increased bit overhead and potentially worse auditory effects due to distortion in the restored audio signals.
Innovation Solution
A method that determines a target reverberation gain parameter based on the energy coherence between channel signals and their downmixed signal, selectively encoding these parameters for only specific subbands, reducing bit overhead and improving encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reverberation gain parameters for each subband are encoded, then the auditory quality is improved, but the bit overhead increases significantly
Solution Approach 1:
The patent extracts and encodes only the necessary reverberation gain parameters by comparing channel signals with downmixed signals. It identifies subbands where reverberation processing is actually needed (where channel signal energy differs from downmixed signal energy) and encodes parameters only for those specific subbands, rather than encoding all subband parameters universally.
Solution Approach 2:
The patent applies different encoding strategies to different subbands based on their local characteristics. For subbands where the channel signal energy is significantly different from the downmixed signal energy, full reverberation gain parameters are encoded. For subbands where energies are similar, simplified or no encoding is performed, optimizing the balance between quality and bit rate locally for each subband.
2Adaptability or versatility
If reverberation processing is performed on each subband, then the spatial audio effect is enhanced, but the auditory quality deteriorates due to distortion
Solution Approach 1:
The patent applies reverberation processing selectively rather than universally across all subbands. It performs reverberation processing only on subbands where it is beneficial (where channel signal energy differs from downmixed signal energy), avoiding excessive processing on subbands where it would cause distortion, thus achieving partial action that balances spatial effect enhancement with quality preservation.
3Loss of information
If all subband parameters are encoded, then the encoding completeness is improved, but the encoding efficiency decreases
Solution Approach 1:
The patent extracts only the essential reverberation gain parameters that need to be encoded by comparing channel signals with downmixed signals. It identifies and encodes parameters only for subbands where reverberation processing is necessary, removing redundant encoding operations for subbands where parameters can be inferred or are not needed, thus improving encoding efficiency while maintaining necessary completeness.
Data Source
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AI summary
A multi-channel signal encoding method, a multi-channel signal decoding method, an encoder, and a decoder are provided. The encoding method includes: determining a downmixed signal of a first channel signal and a second channel signal in a multi-channel signal, and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal (310); determining a target reverberation gain parameter that needs to be encoded in the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal (320); generating parameter indication information, where the parameter indication information is used to indicate a subband corresponding to the target reverberation gain parameter (330); and encoding the target reverberation gain parameter, the parameter indication information, and the downmixed signal to generate a bitstream (340). Encoding efficiency can be improved.