Stereo Voice Pulse Allocation via Channel Correlation
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Solution Overview
Problem
Current speech coding methods, such as AMR-WB, are inefficient for encoding stereo speech signals as they require separate fixed codebook searches for each channel, which is not optimal in terms of coding and processing efficiency.
Innovation Solution
A pulse apportionment method that determines the number of pulses for each channel in a stereo signal based on the characteristics and similarity between channels, allowing for efficient encoding by adjusting the number of pulses in each channel during the fixed codebook search.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual-monaural coding is used for stereo speech signals, then speech quality can be maintained, but coding efficiency and processing efficiency deteriorate due to separate fixed codebook searches for each channel
Solution Approach 1:
The patent merges the fixed codebook search processes of left and right channels by determining pulse positions for one channel and deriving corresponding pulse positions for the other channel based on their correlation. This combining approach maintains speech quality while significantly improving coding efficiency by avoiding redundant separate searches.
Solution Approach 2:
The patent uses the pulse position information from one channel as a reference to generate pulse position information for the other channel. By copying and adapting the pulse positions based on channel correlation, the system maintains high speech quality while reducing the computational burden of separate codebook searches.
2Reliability
If dual-monaural coding is used for stereo speech signals, then speech quality can be maintained, but processing efficiency deteriorates due to separate fixed codebook searches for each channel
Solution Approach 1:
The patent combines the fixed codebook search operations for both channels into a unified process where pulse positions for one channel are determined and then used to derive pulse positions for the other channel. This merging reduces processing time while maintaining speech quality through correlation-based pulse position derivation.
Solution Approach 2:
The patent performs preliminary determination of pulse positions for one channel before processing the other channel. By establishing pulse positions for the first channel in advance and using them as a reference for the second channel, the system reduces overall processing time while maintaining quality through the preliminary pulse position information.
3Reliability
If the number of pulses is increased for each channel, then speech quality improves, but coding efficiency deteriorates due to higher bit rate requirements
Solution Approach 1:
The patent copies pulse position information from one channel to the other channel based on their correlation, rather than encoding completely independent pulse sequences for each channel. This copying approach reduces the total number of bits required while maintaining speech quality by leveraging the redundancy between correlated stereo channels.
Solution Approach 2:
The patent discards redundant pulse position information that would be identical or highly correlated between stereo channels, and recovers the necessary speech quality information through correlation-based derivation. This approach reduces bit rate by eliminating redundant data while maintaining speech quality through intelligent recovery of essential information.
Data Source
AI summary
A pulse allocating method capable of coding stereophonic voice signals efficiently. In the fixed code note retrievals of this pulse allocating method, for individual subframes, the stereophonic voice signals are compared to judge similarity between channels, and are judged on their characteristics. On the basis of the similarity between the channels and the characteristics of the stereophonic signals, the pulse numbers to be allocated to the individual channels are determined. Pulse retrievals are executed to determine the pulse positions for the individual channels, so that the pulses determined are coded.