Bit-Aware High-Frequency Compensation for Monaural and Stereo Decoding
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Solution Overview
Problem
In cases where monaural and stereo encoding/decoding methods are used independently or on terminals with different priorities, the information from the monaural code is not utilized in obtaining the stereo decoded sound signal, leading to inefficiencies.
Innovation Solution
Compensate the high-frequency energy of decoded sound signals by adjusting the high-frequency gain based on the number of bits used in the monaural and stereo codes, combining the monaural and stereo signals to improve the decoded sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent monaural and stereo encoding/decoding methods are used, then decoding can be performed without requiring both codes to arrive, but the information from the monaural code is not utilized in obtaining the stereo decoded sound signal
Solution Approach 1:
The patent merges the monaural decoded sound signal and the stereo decoded sound signal by adding them together to generate the final output sound signal. This combining process allows the system to utilize information from both the monaural code and the stereo code, resolving the information loss issue while maintaining the reliability benefit of independent decoding methods.
Solution Approach 2:
The output sound signal generation unit is designed to handle multiple input scenarios universally: it can process only monaural decoded signals, only stereo decoded signals, or both simultaneously. This multi-functional design allows the system to adapt to different packet arrival conditions while always utilizing available information from both code types when possible.
2Device complexity
If only stereo code is used for stereo decoding, then the decoding process is simple and independent, but the high-frequency energy may be insufficient compared to using both monaural and stereo codes
Solution Approach 1:
The system dynamically adapts its processing based on which codes are available. When both monaural and stereo codes are present, it performs the additional step of adding monaural decoded signal to enhance high-frequency energy. When only stereo code is available, it simply outputs the stereo decoded signal. This dynamic approach improves sound quality when possible without unnecessarily increasing complexity when resources are limited.
3Reliability
If monaural code and stereo code are transmitted with different priorities, then packet loss can be managed by securing minimum quality in high-priority packets, but the information from lower-priority monaural code is not utilized when it does arrive
Solution Approach 1:
The system implements a feedback mechanism where the output sound signal generation unit continuously checks which decoded signals are available and adjusts its processing accordingly. When the monaural decoded signal becomes available (even if from a lower-priority packet), the system detects this and incorporates it into the final output, thereby utilizing information efficiently while maintaining quality assurance through the priority-based transmission structure.
Data Source
AI summary
For each frame, an n-th channel compensated decoded sound signal ˜X′n is obtained that is a signal obtained by compensating a high frequency of an n-th channel purified decoded sound signal ˜Xn obtained by performing signal processing in a time domain on an n-th channel decoded sound signal {circumflex over ( )}Xn obtained by decoding a stereo code CS. At this time, {circumflex over ( )}Xn is selected in a case where the number of bits bn corresponding to an n-th channel in the number of bits of CS is larger than the number of bits bM of a monaural code CM, or a monaural decoded sound signal obtained by decoding CM or a signal obtained by upmixing the monaural decoded sound signal for the n-th channel is selected in a case where bn is smaller than bM, an n-th channel high-frequency compensation gain ρn that is a value for bringing the high-frequency energy of ˜X′n close to the high-frequency energy of {circumflex over ( )}Xn is obtained, and a signal obtained by adding ˜Xn and a signal obtained by multiplying a high-frequency component of the selected signal by ρn is obtained and output as an n-th channel compensated decoded sound signal.