Inter-Channel Time Difference Parameter Determination in Stereo Encoding
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Solution Overview
Problem
Current methods for determining the inter-channel time difference parameter in stereo audio processing require a large search range, leading to increased calculation amounts and reduced processing efficiency.
Innovation Solution
Determine a reference parameter from time-domain signals of two sound channels to establish a reduced search range of [-Tmax, 0] or [0, Tmax] in the frequency domain, allowing for more efficient calculation of the inter-channel time difference parameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large search range [-Tmax, Tmax] is used to determine the ITD parameter in the frequency domain, then the accuracy of the ITD parameter is ensured, but the calculation amount increases and processing efficiency decreases
Solution Approach 1:
The patent performs preliminary cross-correlation calculation in the time domain to obtain a reference value before frequency domain processing. This preliminary action provides a starting point that narrows the subsequent frequency domain search range, reducing calculation amount while maintaining accuracy
Solution Approach 2:
The patent divides the ITD parameter determination process into two stages: time domain cross-correlation to obtain reference value, and frequency domain search within a narrowed range based on the reference value. This segmentation allows each stage to operate efficiently within its optimized scope
2Measurement precision
If a large search range [-Tmax, Tmax] is used to determine the ITD parameter, then the accuracy is maintained, but the performance requirement for the encoder increases
Solution Approach 1:
The time domain cross-correlation is performed as a preliminary step to obtain a reference value that guides the frequency domain search. This preliminary calculation reduces the computational burden on the encoder during frequency domain processing
Solution Approach 2:
The search range in the frequency domain is dynamically adjusted based on the reference value obtained from time domain analysis. The search range becomes [-reference value, reference value] instead of the fixed large range [-Tmax, Tmax], adapting to the actual signal characteristics
Data Source
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AI summary
A method and an apparatus for determining an inter-channel time difference parameter are provided, to reduce a calculation amount in a process of searching for and calculating an inter-channel time difference in a stereo encoding process. The method includes: determining a reference parameter according to a time-domain signal on a first sound channel and a time-domain signal on a second sound channel, where the reference parameter is corresponding to a sequence of obtaining the time-domain signal on the first sound channel and the time-domain signal on the second sound channel, and the time-domain signal on the first sound channel and the time-domain signal on the second sound channel are corresponding to a same time period (S110); determining a search range according to the reference parameter and a limiting value Tmax, where the limiting value Tmax is determined according to a sampling rate of the time-domain signal on the first sound channel, and the search range falls within [-Tmax, 0], or the search range falls within [0, Tmax] (S120); and performing search processing within the search range based on a frequency-domain signal on the first sound channel and a frequency-domain signal on the second sound channel, to determine a first inter-channel time difference ITD parameter corresponding to the first sound channel and the second sound channel (S130).