Decoded Stereo Audio High-Frequency Compensation with Monaural Code Gain
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Solution Overview
Problem
In cases where communication is performed by terminals connected to two lines with different priorities, or where monaural and stereo encoding/decoding methods are used independently, the information from the monaural code is not utilized in stereo decoding, leading to incomplete stereo sound signal processing.
Innovation Solution
A method to compensate the high-frequency energy of decoded stereo signals by adding a high-frequency component from a monaural decoded signal, using a high-frequency compensation gain to improve the stereo signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If stereo decoding is performed independently without utilizing monaural code information, then decoding complexity is reduced, but the quality of decoded stereo sound signal deteriorates due to loss of high-frequency information
Solution Approach 1:
The patent merges the monaural decoded sound signal with the stereo decoded sound signal by adding the monaural signal to each channel of the stereo signal. This combining process utilizes the high-frequency information contained in the monaural code to enhance the quality of the decoded stereo sound signal, resolving the contradiction between signal quality and decoding complexity.
2Manufacturing precision
If high-frequency compensation is applied by adding monaural decoded signal to stereo decoded signal, then the quality of decoded stereo sound signal is improved, but processing complexity increases
Solution Approach 1:
The patent applies parameter changes by introducing a high-frequency compensation gain (rho_n) that scales the monaural decoded signal before addition. This gain parameter allows flexible control of the compensation strength, enabling optimization of signal quality while managing processing complexity through adjustable weighting rather than fixed complex processing.
Data Source
AI summary
For each frame, an n-th channel compensated decoded sound signal {tilde over ( )}X′n is obtained that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal {tilde over ( )}Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal {circumflex over ( )}Xn that is a decoded sound signal of each channel of stereo obtained by decoding a stereo code CS. At this time, for the each frame with respect to the each channel, an n-th channel high-frequency compensation gain ρn that is a value for bringing high-frequency energy of {tilde over ( )}X′n close to high-frequency energy of {circumflex over ( )}Xn is obtained, and for the each frame with respect to the each channel, a signal obtained by adding {tilde over ( )}Xn and a signal obtained by multiplying a high-frequency component of a monaural decoded sound signal that is obtained by decoding a monaural code CM that is a code different from the stereo code CS or a signal obtained by upmixing, for the each channel, the monaural decoded sound signal by the n-th channel high-frequency compensation gain ρn is obtained and output as the n-th channel compensated decoded sound signal {tilde over ( )}X′n.