Audio Playback Acceleration via Detection Period Metadata
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Solution Overview
Problem
Echo and audio synchronization issues in audio communication sessions, such as VoIP, where conventional techniques either fail to effectively prevent echo or result in pitch modification during playback acceleration.
Innovation Solution
A method involving voice activity detection to identify speech inputs, transmitting only the speech portion with a detection period duration, and removing redundant pitch periods at the receiving device to accelerate playback without affecting pitch, using autocorrelation to identify and remove pitch periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional echo prevention techniques are used, then echo can be suppressed, but audio synchronization delays increase and pitch modification occurs during playback acceleration
Solution Approach 1:
The system performs preliminary voice activity detection and identifies speech portions before transmission. By detecting the detection period duration in advance and communicating this metadata to the receiving device, the system enables the receiving device to pre-calculate the appropriate playback acceleration, thereby reducing synchronization delays without causing pitch modification.
Solution Approach 2:
The patent introduces detection period duration metadata as an intermediary element between the transmitting and receiving devices. This metadata acts as a communication bridge that conveys timing information, allowing the receiving device to adjust playback timing accurately without directly manipulating the audio signal, thus avoiding pitch modification while reducing synchronization delays.
2Loss of time
If playback acceleration is applied to compensate for detection period, then synchronization is improved, but pitch modification occurs
Solution Approach 1:
The transmitting device performs preliminary voice activity detection to identify the detection period duration before encoding and transmitting the audio signal. By providing this timing information in advance through metadata, the receiving device can calculate the exact acceleration needed and apply it precisely, compensating for the detection period while maintaining pitch integrity through accurate timing adjustment rather than signal manipulation.
Solution Approach 2:
The system uses feedback through metadata transmission, where the detection period duration is communicated from the transmitting to the receiving device. This feedback mechanism enables the receiving device to adjust playback timing based on accurate timing information, achieving synchronization without pitch modification by using timing-based adjustment rather than signal processing-based acceleration.
3Measurement precision
If voice activity detection is performed with longer analysis period, then detection accuracy is improved, but transmission delay increases
Solution Approach 1:
The detection period duration metadata serves as an intermediary that communicates the actual detection time taken. By transmitting this metadata alongside the audio signal, the system allows the receiving device to understand the precise detection period that was used, enabling accurate synchronization compensation without requiring a longer detection period than necessary for adequate accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces echo and synchronization delays without requiring user intervention and maintains audio pitch integrity, offering faster playback synchronization while minimizing buffering issues.
Implementation Method 1
using autocorrelation to identify and remove pitch periods
Data Source
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Figure 3
AI summary
A computer-implemented technique can include establishing an audio communication session between first and second computing devices and obtaining, by the first computing device, an audio input signal using audio data captured by a microphone. The first computing device can analyze the audio input signal to detect a speech input by its first user and can determine a duration of a detection period from when the audio input signal was obtained until the analyzing has completed. The first computing device can then transmit, to the second computing device, (i) a portion of the audio input signal beginning at a start of the speech input and (ii) the detection period duration, wherein receipt of the portion of the audio input signal and the detection period duration causes the second computing device to accelerate playback of the portion of the audio input signal to compensate for the detection period duration.