Multi-Channel Signal Decoding Using Estimated Phase Parameters
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Solution Overview
Problem
Existing multi-channel signal encoding and decoding technologies face challenges in efficiently transmitting and decoding stereo parameters at low bit rates, leading to suboptimal quality of the multi-channel signal due to the lack of phase information in the encoding process.
Innovation Solution
The method involves down-mixing a multi-channel signal to a mono-signal, extracting and encoding stereo parameters such as inter-channel intensity difference (IID), inter-channel coherence (ICC), and inter-channel phase difference (IPD), while estimating the overall phase difference (OPD) at the decoding stage to improve signal quality by up-mixing the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stereo parameters are transmitted at low bit rate, then transmission efficiency is improved, but signal quality deteriorates due to loss of phase information
Solution Approach 1:
The patent extracts and transmits only essential stereo parameters (IID, ICC, IPD) at low bit rate, separating the phase information transmission from the full signal transmission. This allows efficient transmission while maintaining quality through selective parameter extraction.
Solution Approach 2:
The patent performs preliminary extraction and encoding of stereo parameters during the encoding phase, preparing the necessary phase information (IPD, OPD) in advance. This preliminary action enables the decoder to reconstruct high-quality signals without transmitting all original data.
2Manufacturing precision
If all stereo parameters are transmitted, then signal quality is improved, but transmission bandwidth increases
Solution Approach 1:
The patent extracts only the necessary stereo parameters (IID, ICC, IPD) that capture the essential spatial and phase relationships, discarding redundant information. This extraction approach maintains signal quality while minimizing transmission bandwidth requirements.
Solution Approach 2:
The patent transforms the multi-channel signal into a compact representation using stereo parameters (IID, ICC, IPD, OPD), changing the form of information from raw audio data to compressed parametric representation. This parameter transformation achieves efficient bandwidth utilization.
3Device complexity
If phase information is excluded from encoding, then encoding complexity is reduced, but decoding accuracy deteriorates
Solution Approach 1:
The patent extracts phase information in the form of IPD (inter-channel phase difference) and OPD (overall phase difference) parameters during encoding. This extraction approach captures essential phase relationships without requiring complex full-signal processing, balancing encoding simplicity with decoding accuracy.
Solution Approach 2:
The patent changes the representation of phase information from raw waveform data to compact parametric form (IPD, OPD). This parameter transformation simplifies the encoding process while preserving the phase information necessary for accurate decoding and up-mixing operations.
Data Source
AI summary
A multi-channel signal decoding method is provided. A down-mixed signal representative of a multi-channel signal is decoded, and parameters representing characteristic relations between channels of the multi-channel signal are decoded. An additional parameter is estimated by using the decoded parameters, and the decoded down-mixed signal is up-mixed by using the decoded parameters and the estimated parameter so as to decode the multi-channel signal.