Restart microphone capture on audio device change#311
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Jun 15, 2026
| var outputSampleRate = (uint)AudioSettings.outputSampleRate; | ||
| if (outputSampleRate != _expectedSampleRate) | ||
| { | ||
| Utils.Warning($"MicrophoneSource: audio device change moved the DSP output rate to {outputSampleRate}Hz, but the native source is fixed at {_expectedSampleRate}Hz. Captured frames will be dropped until the track is recreated at the new rate."); |
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Triggered on Unity 6 editor on mac starting with MDR-1000x, disabling Bluetooth to switch to built in mic, then connecting to MDR-1000x again:
LiveKit: MicrophoneSource: audio device change moved the DSP output rate to 44100Hz, but the native source is fixed at 48000Hz. Captured frames will be dropped until the track is recreated at the new rate.
UnityEngine.Logger:LogWarning (string,object)
LiveKit.Internal.Utils:Warning (object) (at /Users/maxheimbrock/dev/unity/client-sdk-unity/Runtime/Scripts/Internal/Utils.cs:41)
LiveKit.MicrophoneSource:OnAudioConfigurationChanged (bool) (at /Users/maxheimbrock/dev/unity/client-sdk-unity/Runtime/Scripts/MicrophoneSource.cs:248)
UnityEngine.AudioSettings:InvokeOnAudioConfigurationChanged (bool) (at /Users/bokken/build/output/unity/unity/Modules/Audio/Public/ScriptBindings/Audio.bindings.cs:413)
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This worked on https://github.com/livekit/client-sdk-unity/pull/312/changes
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When a capture device disappears mid-call (e.g. unplugging a Bluetooth headset), the local microphone went silent and never recovered: MicrophoneSource stayed bound to the gone device name and never re-registered the AudioProbe tap that Unity detaches when it rebuilds its audio graph. Subscribe to AudioSettings.OnAudioConfigurationChanged (mirroring the playback-side AudioStream handler) and restart capture on a device change, resolving to the OS default device when the preferred device is no longer present. Track the active device separately from the preferred one so Microphone.IsRecording/GetPosition/End target the right device, and guard against overlapping restarts. The native source's rate is fixed at construction, so if the device change moves Unity's DSP output rate, frames are still dropped; warn clearly in that case. Full rate-change recovery follows separately. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Problem
When a capture device disappears mid-call (e.g. unplugging a Bluetooth headset and falling back to the built-in mic), the local microphone went silent and never recovered:
MicrophoneSourcestayed bound to the now-gone device name and never re-resolved to the new default.AudioProbe.OnAudioFilterReadtap — so even the capture tap stopped firing.The playback side already handles this in
AudioStream.OnAudioConfigurationChanged; this mirrors that pattern for capture.Change
MicrophoneSourcetoAudioSettings.OnAudioConfigurationChangedand restart capture on a device change (reusing the existingRestartMicrophonecoroutine, which re-adds theAudioSource/AudioProbeand re-registers the tap on the rebuilt graph).null) when the preferred device is gone, so an unplugged headset transparently hands off to the built-in mic.Microphone.IsRecording/GetPosition/Endtarget the device actually recording.The native source's rate is fixed at construction, so if the device change moves Unity's DSP output rate, frames are still dropped; this case is warned about clearly. Full rate-change recovery is a follow-up (stacked PR).
Testing
Scripts~/run_unity.sh build macos→ Build SUCCEEDED.🤖 Generated with Claude Code