Encoder and Decoder Disentangling Style and Content for Low-Bitrate Speech
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Solution Overview
Problem
State-of-the-art neural speech coding methods face inefficiencies in encoding and decoding speech signals due to the entanglement of long-term speaker identity and short-term phonetic content information, leading to suboptimal coding efficiency and privacy concerns.
Innovation Solution
The proposed solution involves disentangling content and style information using separate encoders, where the style encoder handles long-term speaker identity and the content encoder manages short-term phonetic content, allowing for separate transmission and decoding of these streams, enabling improved coding efficiency and privacy preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If content and style information are encoded together in a single neural network, then the encoding process is simpler, but coding efficiency is reduced and privacy concerns arise
Solution Approach 1:
The patent divides the encoding process into two separate neural networks: a style encoder that extracts long-term speaker characteristics and a content encoder that processes short-term phonetic information. This segmentation allows each encoder to be optimized for its specific function, improving overall coding efficiency while maintaining manageable complexity
Solution Approach 2:
The patent extracts style information separately from content information by using a dedicated style encoder that processes the input audio signal independently. This extracted style representation is then used to condition the content decoding process, enabling efficient coding while preserving speaker identity for privacy applications
2Manufacturing precision
If style information is transmitted at high frequency, then speech reconstruction quality improves, but transmission bandwidth and power consumption increase
Solution Approach 1:
The patent transmits style information periodically at a lower frequency than content information. Since style characteristics change slowly over time, this periodic transmission at reduced frequency maintains speech reconstruction quality while significantly reducing transmission power consumption and bandwidth requirements
3Device complexity
If content and style information are transmitted over the same channel, then transmission is simpler, but error protection is suboptimal
Solution Approach 1:
The patent segments the transmitted data into separate style and content streams that can be sent over different channels or with different error protection schemes. This allows critical style information to receive enhanced error protection while content information uses standard protection, optimizing overall reliability without excessive complexity
Solution Approach 2:
The patent applies different error protection strategies to different parts of the transmitted data based on their importance. Style information, which carries speaker identity, can be protected with higher redundancy or more robust coding schemes, while content information uses lighter protection, optimizing the trade-off between reliability and complexity
Data Source
Figure 1~2
Figure 3a~3b
AI summary
Encoder (10') for encoding an input audio signal (IS), comprising: a style encoder (10s) configured to encode style information of the input audio signal (IS) to obtain a first data stream (Q1); a content encoder (10c) configured to encode content information to obtain a second data stream (Q2).