Speech Encoder Phase Quantization for Low-Bitrate Coding
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Solution Overview
Problem
Conventional speech codecs struggle in very low bitrate scenarios due to insufficient bandwidth or transmission quality issues, leading to poor performance in real-time communication.
Innovation Solution
Implement phase quantization and reconstruction techniques in speech encoding and decoding, using a linear component and weighted sum of basis functions to efficiently represent and synthesize phase values, omitting higher-frequency phase values during encoding and synthesizing them during decoding based on lower-frequency values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional speech codecs are used in very low bitrate scenarios, then bandwidth consumption is reduced, but speech quality deteriorates due to insufficient bandwidth or transmission quality problems
Solution Approach 1:
The patent extracts only the essential phase information (phase values at selected frequency points) from the full spectral representation, transmitting only these critical parameters while deriving the rest at the decoder. This selective extraction maintains speech quality by preserving the most important phase relationships while minimizing transmitted data volume.
Solution Approach 2:
The patent creates a simplified copy of the phase spectrum by representing phase values through a compact set of parameters (phase values at selected frequency points) that can be used to reconstruct or approximate the full phase spectrum at the decoder, maintaining quality while reducing bitrate.
2Measurement precision
If phase values are fully transmitted to maintain accuracy, then speech quality is improved, but bandwidth consumption increases
Solution Approach 1:
The patent extracts only the essential phase information (phase values at selected frequency points) from the full spectral representation, transmitting only these critical parameters while deriving the rest at the decoder. This selective extraction maintains speech quality by preserving the most important phase relationships while minimizing transmitted data volume.
Solution Approach 2:
The patent transmits phase values at a subset of frequency points rather than all frequency points, applying partial action where the most critical phase information is transmitted while accepting approximation at other frequencies. This approach achieves sufficient precision for speech quality without the bandwidth cost of complete phase transmission.
3Manufacturing precision
If all phase values are encoded and transmitted, then reconstruction accuracy is improved, but encoding complexity and transmission data increase
Solution Approach 1:
The patent extracts only the essential phase information (phase values at selected frequency points) from the full spectral representation, transmitting only these critical parameters while deriving the rest at the decoder. This selective extraction maintains speech quality by preserving the most important phase relationships while minimizing transmitted data volume.
Solution Approach 2:
The patent creates a simplified copy of the phase spectrum by representing phase values through a compact set of parameters (phase values at selected frequency points) that can be used to reconstruct or approximate the full phase spectrum at the decoder, maintaining quality while reducing bitrate.
Data Source
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AI summary
Innovations in phase quantization during speech encoding and phase reconstruction during speech decoding are described. For example, to encode a set of phase values, a speech encoder omits higher-frequency phase values and/or represents at least some of the phase values as a weighted sum of basis functions. Or, as another example, to decode a set of phase values, a speech decoder reconstructs at least some of the phase values using a weighted sum of basis functions and/or reconstructs lower-frequency phase values then uses at least some of the lower-frequency phase values to synthesize higher-frequency phase values. In many cases, the innovations improve the performance of a speech codec in low bitrate scenarios, even when encoded data is delivered over a network that suffers from insufficient bandwidth or transmission quality problems.