Call Downlink Audio Limiting for Consistent Earphone Volume
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Solution Overview
Problem
During phone calls using earphones, near-end users often face challenges in maintaining consistent volume due to variations in the far-end speaker's voice levels, leading to poor call experiences.
Innovation Solution
An audio limiting system and method are introduced in the downlink algorithm of a near-end device, which includes an audio limiting module that receives far-end sound, performs voice activity detection, and adjusts the volume for each audio frame by calculating the difference between the current and target volumes, and applying this gain only to the speech parts while suppressing noise during non-speech segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the far-end speaker speaks loudly, then the volume transmitted to the near-end user increases, but this causes sudden volume surges that deteriorate the call experience
Solution Approach 1:
The system dynamically adjusts the gain applied to audio frames based on real-time voice activity detection and volume level assessment. The gain value changes adaptively to maintain target volume while responding to far-end speaker's volume variations, resolving the contradiction between transmitting adequate volume and preventing sudden surges
Solution Approach 2:
The system implements a feedback mechanism by continuously monitoring the volume level of received audio frames and adjusting the gain accordingly. The volume adjustment logic uses feedback from volume calculations to modulate the output, ensuring that volume surges are prevented while maintaining call quality
2Quantity of substance
If the far-end speaker is far away from the phone, then the transmitted volume decreases, but this makes it difficult for the near-end user to hear clearly
Solution Approach 1:
The system changes the volume parameter dynamically by applying gain adjustment to audio frames. When the detected volume is below the target threshold, the system increases the gain to amplify the signal, making distant speaker voices audible while preventing excessive amplification of background noise through voice-activity-based processing
3Stability of the object's composition
If volume adjustment is applied to all audio frames, then consistent volume is maintained, but background noise is also amplified during non-speech segments
Solution Approach 1:
The system segments audio processing by applying volume adjustment only to speech-containing frames identified through voice activity detection. Non-speech frames are excluded from gain application, thereby maintaining volume consistency during speech while preventing background noise amplification during silent or noisy segments
Solution Approach 2:
The system applies partial action by selectively processing only the necessary portion of audio frames (those containing speech) rather than applying uniform volume adjustment to all frames. This partial processing approach achieves volume consistency where needed while avoiding harmful noise amplification
Data Source
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AI summary
A system for audio limiting in a call downlink algorithm during a call is provided, the audio limiter enables automatic amplification of the low pitch and suppression of the high pitch on the earphone side and prevents distortion of the high pitch, so that the audio limiter can ensure that an earphone wearer can clearly understand the voice content and maintain a consistent volume level regardless of whether the sound of a far-end speaker is small or large.