Multi-channel audio encoder switching between parametric and individual encoding
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Solution Overview
Problem
Existing parametric stereo systems struggle to accurately reproduce the stereo image and deliver intelligible speech output in scenarios with interfering talkers, especially when talkers have different Inter-channel Time Differences (ITDs) and are positioned oppositely around the microphone arrangement.
Innovation Solution
A multi-channel audio encoder and decoder that dynamically switch between parametric multi-channel encoding and individual channel encoding based on characteristics of the input audio representation, such as the presence of multiple sources or significant changes in ITD, to adapt to the specific audio conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If parametric stereo techniques are used for low bitrate transmission, then bitrate efficiency is improved, but stereo image reproduction quality deteriorates in interfering talker scenarios
Solution Approach 1:
The encoder dynamically switches between parametric multi-channel encoding and individual channel encoding based on real-time analysis of the audio signal characteristics. When interfering talkers are detected, the system transitions from parametric mode to individual channel mode, allowing adaptive optimization of both bitrate efficiency and stereo image quality depending on the acoustic scene.
Solution Approach 2:
The system changes the encoding parameters by switching between two distinct encoding modes: parametric multi-channel encoding for efficient compression of single-talker scenarios and individual channel encoding for accurate reproduction of multi-talker scenarios. This parameter change allows the system to optimize the trade-off between compression efficiency and reconstruction quality based on the input conditions.
2Device complexity
If parametric stereo encoding is used, then encoding complexity is reduced, but speech intelligibility deteriorates when talkers are positioned oppositely around the microphone arrangement
Solution Approach 1:
The encoder analyzes the audio signal to detect the presence of interfering talkers and dynamically switches between encoding modes. When talkers are positioned oppositely creating interference, the system transitions to individual channel encoding, which maintains speech intelligibility by preserving the distinct acoustic signatures of each talker, while using simpler parametric encoding when the acoustic scene is unambiguous.
3Reliability
If individual channel encoding is used, then stereo image accuracy is improved, but bitrate efficiency deteriorates
Solution Approach 1:
The system changes the encoding parameters by selecting between parametric multi-channel encoding for high bitrate efficiency when the acoustic scene allows and individual channel encoding for high stereo image accuracy when interfering talkers are present. This adaptive parameter selection optimizes the bitrate-quality trade-off based on the specific audio conditions.
Data Source
AI summary
A multi-channel audio encoder for providing an encoded audio representation on the basis of an input audio representation is provided. The multi-channel audio encoder is configured to switch between a parametric multi-channel encoding of a plurality of channels and an individual encoding of a plurality of channels in dependence on characteristics of the input audio representation.