Multi-Channel Audio Encoding via Channel Similarity
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Solution Overview
Problem
The challenge in modern telecommunication is the increased data complexity and storage costs associated with transmitting and storing stereo audio signals, which are more difficult and expensive than mono signals due to redundant information across channels, affecting sound quality when traditional encoding methods are used.
Innovation Solution
A method and apparatus that encode multi-channel signals into a first signal containing information from one channel and a second signal containing information from two channels based on similarity, using techniques like Left/Side (L/S) and Mid/Side (M/S) encoding to remove redundant information without degrading sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If each channel signal of multi-channel signals is independently encoded, then the encoding process is simple, but the amount of data increases by a factor of the number of channels
Solution Approach 1:
The patent combines multiple channel signals into a smaller number of encoded signals by exploiting temporal and spectral redundancies. Instead of encoding each channel independently, the system merges information across channels and time to produce a compressed representation that requires fewer bits while maintaining audio quality.
Solution Approach 2:
The encoded signals serve multiple functions simultaneously: they represent multiple original channels, maintain audio quality, and reduce data quantity. The encoding scheme creates universal signals that can be used for both high-quality audio reproduction and efficient storage/transmission.
2Quantity of substance
If the sampling rate is reduced to decrease data amount, then the data transmission load is reduced, but the sound quality is directly affected
Solution Approach 1:
The patent changes the representation parameters of audio signals by transforming them into a different domain (frequency domain via MDCT) and reorganizing them into encoded signals with different temporal and spectral characteristics. This parameter transformation allows efficient compression without sacrificing perceptual quality.
3Quantity of substance
If lossy encoding is employed to reduce data amount, then the data transmission load is reduced, but sound quality may be degraded
Solution Approach 1:
The patent applies different encoding strategies to different parts of the audio signal based on their importance. Less critical components are compressed more aggressively, while important audio information is preserved with higher fidelity. This local differentiation of quality levels allows efficient compression without noticeable degradation.
4Quantity of substance
If multi-channel signals are encoded based on channel similarity, then redundant information is removed and data amount is reduced, but the encoding complexity increases
Solution Approach 1:
The patent segments the audio signal into frequency bands using MDCT transformation, allowing independent processing and encoding of different frequency components. This segmentation enables efficient exploitation of redundancies within and across channels while keeping the complexity of each processing stage manageable.
Solution Approach 2:
The patent introduces encoded signals as intermediary representations that bridge the original multi-channel signals and the final compressed output. These intermediate encoded signals facilitate the removal of redundancies while preserving essential audio information, simplifying the overall encoding process.
Data Source
AI summary
A method of encoding multi-channel signals having two or more channels into a first signal and a second signal, and an apparatus to perform the method, the method including generating the first signal by performing a first operation using a first channel signal in the multi-channel signals; and generating the second signal by performing a second operation using a combination of the first channel signal and a second channel signal in the multi-channel signals.