Bluetooth Audio Capture Synchronization Using Playback Feedback
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Solution Overview
Problem
Bluetooth audio communications experience noticeable delays, particularly in matching audio playback and capture, leading to inaccuracies in applications like karaoke and video commentary, where precise synchronization is required.
Innovation Solution
A method for synchronizing captured audio with playback using feedback signals to determine and model transmission and return delays, allowing for accurate alignment of audio streams through cross-correlation and noise reduction techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Bluetooth audio transmission is used for wireless communication, then ease of operation is improved, but measurement precision of audio synchronization deteriorates due to noticeable delays
Solution Approach 1:
The patent employs feedback mechanisms where the receiving device transmits back acknowledgment signals and timing information about when audio packets were received and processed. This feedback loop enables the sending device to calculate actual transmission delays and adjust synchronization parameters accordingly, resolving the contradiction between easy wireless operation and precise audio timing.
Solution Approach 2:
The patent implements preliminary actions by pre-calculating buffer sizes, pre-establishing timing parameters, and pre-processing audio packets with timestamps before transmission. This allows the receiving device to anticipate delays and prepare appropriate buffer allocations in advance, maintaining synchronization precision while preserving the ease of wireless operation.
2Ease of operation
If Bluetooth HFP profile is used for voice communication, then ease of operation is improved, but manufacturing precision of audio quality deteriorates due to limited sampling rate and fixed encoding rate
Solution Approach 1:
The patent applies dynamics by making the audio encoding parameters variable rather than fixed. The system dynamically adjusts sampling rates, encoding bitrates, and packet sizes based on real-time conditions such as network quality, audio complexity, and device capabilities. This allows the system to maintain ease of operation while achieving high audio quality through adaptive rather than static encoding.
Solution Approach 2:
The patent implements parameter changes by allowing the audio transmission system to modify key parameters including sampling frequency, channel width, and encoding bitrate on a per-packet basis. This flexibility enables the system to optimize both operational simplicity and audio quality by selecting appropriate parameters for each transmission condition rather than being constrained to fixed HFP parameters.
3Manufacturing precision
If A2DP profile is used for high quality audio transmission, then manufacturing precision of audio quality is improved, but measurement precision of synchronization deteriorates due to asynchronous packet scheduling
Solution Approach 1:
The patent uses feedback mechanisms where the receiving device reports actual packet arrival times, buffer fill times, and playback timestamps back to the sending device. This feedback enables precise measurement of asynchronous scheduling effects and allows the sending device to adjust packet timing and sequencing to maintain synchronization while preserving high audio quality through A2DP.
Solution Approach 2:
The patent replaces rigid mechanical timing mechanisms with flexible software-based timing adjustment. Instead of relying on fixed scheduling intervals that cause synchronization drift, the system uses software algorithms to measure actual packet transmission and reception characteristics, then dynamically adjusts playback timing to compensate for asynchronous scheduling effects while maintaining high audio quality.
Data Source
AI summary
Processes, methods, systems, and devices are disclosed for synchronizing wirelessly transmitted captured audios to audio output. In an aspect, a user device transmits an audio output associated with the audio playback to a wireless audio device. The user device receives a feedback signal corresponding to the audio output played at the wireless audio device. The user device further receives a captured audio from the wireless audio device. The user device synchronizes the captured audio with the audio output based on the feedback signal. For example, the audio output may be an instrumental soundtrack and the captured audio may be a recording of the user's singing in response to the instrumental soundtrack. In other examples, the audio output may be a soundtrack from a video playback or live streaming. The captured audio may be a commentary or a response to the video playback or the live streaming.