Recreate audio source and republish track on sample-rate change#312
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Recreate audio source and republish track on sample-rate change#312MaxHeimbrock wants to merge 1 commit into
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Commit 1 restarts capture on a device change but the native source's rate stays fixed at construction, so a device whose rate differs from the original silently has every frame dropped. Add RtcAudioSource.Reconfigure(sampleRate, channels): it disposes the old native handle, rebuilds the source at the new format, and raises a new FormatChanged event. The native source stays alive via the track's reference until the track is dropped, so disposing the handle before the old track is unpublished is safe. The FFI exposes no in-place source reconfigure, so a fresh source (and re-bound track) is required. MicrophoneSource detects the format change via ResolveDeviceFormat in its config-changed handler and calls Reconfigure inside the restart while capture is paused (no AudioRead callbacks in flight). MeetManager subscribes to FormatChanged and republishes the local audio track against the source's new handle. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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MaxHeimbrock
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Jun 15, 2026
| if (sampleRate == 0 || channels == 0) return false; | ||
| if (sampleRate == _expectedSampleRate && channels == _expectedChannels) return false; | ||
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| Utils.Debug($"{DebugTag} reconfigure {_expectedSampleRate}/{_expectedChannels} -> {sampleRate}/{channels}"); |
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Without this change, we can have:
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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Problem
#311 restarts capture on a device change, but the native audio source's rate is fixed at construction. If the new device has a different sample rate,
RtcAudioSourcesilently drops every captured frame (it rejects frames whose rate/channels don't match the source) — so audio stays dead.The FFI exposes no in-place source reconfigure (only
NewAudioSource), so recovery requires a fresh native source and a re-bound track.Change
RtcAudioSource.Reconfigure(sampleRate, channels): disposes the old native handle, rebuilds the source at the new format, and raises a newFormatChangedevent. The native source stays alive via the track's reference until the track is dropped, so disposing the handle before the old track is unpublished is safe.MicrophoneSourcedetects the format change viaResolveDeviceFormatin its config-changed handler and callsReconfigureinside the restart while capture is paused (noAudioReadcallbacks in flight), replacing the warning from Restart microphone capture on audio device change #311.MeetManagersubscribes toFormatChangedand republishes the local audio track against the source's new handle (unsubscribing on unpublish/cleanup).Note
Republishing yields a new track SID, so remote peers resubscribe on a rate change — acceptable but observable.
Testing
Scripts~/run_unity.sh build macos→ Build SUCCEEDED.🤖 Generated with Claude Code