Audio Resampling with Sub-Sample Interpolation for Playback Overrun
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Solution Overview
Problem
Audio playback overrun and underrun issues in wireless speaker and headset systems lead to compromised audio quality due to clock synchronization discrepancies between host and receiver devices, resulting in dropped or repeated audio data.
Innovation Solution
A method for resampling audio signals by slicing each sample into sub-samples and adjusting the sample rate to maintain playback quality, using linear interpolation and arithmetic shift operations to minimize computational cycles and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excess audio data is dropped when audio playback overrun happens, then the audio playback can continue, but the audio playback quality is compromised
Solution Approach 1:
The patent divides each audio sample into multiple sub-samples (e.g., 4 sub-samples per sample). This segmentation allows the system to selectively use or discard sub-samples based on playback conditions, enabling quality preservation during overrun events by discarding only excess sub-samples rather than entire samples.
Solution Approach 2:
The patent generates more sub-samples than originally needed by slicing each sample into multiple parts. This excessive action provides flexibility to discard partial content (excess sub-samples) when overrun occurs, while maintaining sufficient quality through the remaining sub-samples.
2Reliability
If the last audio data is repeated when audio playback underrun occurs, then the audio playback can continue, but the audio playback quality is compromised
Solution Approach 1:
By dividing samples into sub-samples, the system can selectively repeat only certain sub-samples during underrun events rather than repeating entire samples. This partial repetition maintains audio quality better than full sample repetition.
Solution Approach 2:
The patent applies different quality handling to different parts of the audio data. During underrun, specific sub-samples are repeated while others are not, creating local quality adjustments that preserve overall audio fidelity better than uniform repetition.
3Manufacturing precision
If linear interpolation is used to slice audio samples into sub-samples, then audio playback quality is preserved, but computational complexity increases
Solution Approach 1:
The patent replaces complex floating-point arithmetic operations with fixed-point arithmetic and bit shift operations for the interpolation calculations. This substitution maintains the quality benefits of linear interpolation while significantly reducing computational complexity and hardware requirements.
Solution Approach 2:
The patent changes the numerical representation parameters from floating-point to fixed-point format, and uses bit shift operations instead of division/multiplication. This parameter change preserves interpolation accuracy while reducing computational complexity.
4Manufacturing precision
If audio resampling is performed to handle clock offset accumulation, then audio playback quality is maintained, but processing time increases
Solution Approach 1:
The patent processes audio data in blocks and performs resampling on segmented data rather than continuous streams. This block-based segmentation allows for more efficient batch processing and reduces overall processing time while maintaining quality.
Solution Approach 2:
By replacing floating-point operations with fixed-point arithmetic and bit shifts, the patent significantly reduces the computational time required for each resampling operation, making real-time processing feasible.
Data Source
AI summary
A method, a computer-readable medium, and an apparatus for resampling audio signal are provided. The apparatus resamples the audio signal in order to preserve the audio playback quality when dealing with audio playback overrun and underrun problem. The apparatus may receive a data block of the audio signal including a first number of samples. For each sample of the first number of samples, the apparatus may slice a portion of the audio signal corresponding to the sample into a particular number of sub-samples. The apparatus may resample the data block of the audio signal into a second number of samples based on the first number of samples and the particular number of sub-samples associated with each sample of the first number of samples. The apparatus may play back the resampled data block of the audio signal via an electroacoustic device.