Audio Decoding of High-Frequency Sine Wave Start Positions
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Solution Overview
Problem
The existing SBR-based audio decoding methods face challenges in accurately reproducing high frequency components due to variance in the emergence start position of sine wave components, leading to degradation in audio quality, especially at lower sampling rates where quantization noise becomes noticeable.
Innovation Solution
The proposed solution involves adjusting the combination start position of the sine wave signal independently of the noise boundary position, allowing for a more accurate prediction of high frequency components by specifying this position based on the sampling rate, thereby reducing unnecessary signal combinations and enhancing audio quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the combination start position of the sine wave signal is set to the SBR frame start position or noise boundary position, then the decoding process is simplified, but the accuracy of reproducing high frequency components deteriorates due to variance in the emergence start position of sine wave components
Solution Approach 1:
The patent applies preliminary action by detecting the emergence start position of sine wave components during the encoding phase and storing this information in the bitstream. This allows the decoding device to use the pre-detected position information directly, avoiding the need to search for the position during decoding while maintaining accurate reproduction of high frequency components.
Solution Approach 2:
The patent introduces an intermediary element - the sine wave component position information - that acts as a bridge between the encoding and decoding processes. This position information is extracted during encoding and transmitted through the bitstream, enabling the decoding device to accurately reconstruct the high frequency components without having to perform complex analysis.
2Device complexity
If the sine wave signal is combined at fixed positions (SBR frame start or noise boundary), then the device complexity is reduced, but the audio quality deteriorates due to quantization noise becoming noticeable at lower sampling rates
Solution Approach 1:
The emergence start position of sine wave components is detected and recorded during encoding before transmission. This preliminary detection eliminates the need for complex real-time position determination during decoding, reducing device complexity while maintaining audio quality through accurate position-based sine wave signal combination.
Solution Approach 2:
The patent changes the parameter of sine wave combination from fixed positions to dynamically determined positions based on detected emergence points. By transmitting the detected position information in the bitstream and using it during decoding, the system achieves accurate audio reconstruction without requiring complex processing hardware.
Data Source
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AI summary
The present technology relates to a signal processing device, method, and program that may obtain audio at a higher audio quality when decoding an audio signal. An envelope information generating unit 24 generates envelope information representing an envelope form of high frequency components of an audio signal to be encoded. A sine wave information generating unit 26 extracts a sine wave signal from the high frequency components of the audio signal, and generates a sine wave information representing an emergence start position of the sine wave signal. An encoding stream generating unit 27 multiplexes the envelope information, the sine wave information, and low frequency components of the audio signal that have been encoded, and outputs an encoding stream obtained as the result. As a result, the high frequency components included in the sine wave signal may be predicted at a higher accuracy from the envelope information and the sine wave information at the receiving side of the encoding stream. The present invention may be applied to a signal processing device.