Microphone_StartRecording: Firefox fails with "Connecting AudioNodes from AudioContexts with different sample-rate is currently not supported"

[Zarbuz]

Environment

• Firefox (all versions)
• WebGL platform

Bug

In UnityMicrophoneLibrary.jslib, Microphone_StartRecording creates an AudioContext with a forced sample rate:

  const audioContext = new AudioContext({ sampleRate: frequency });
  const source = audioContext.createMediaStreamSource(stream);

Firefox does not support connecting a MediaStreamSource (which runs at the device's native sample rate, e.g. 48000) to an AudioContext with a different sample rate (e.g. 24000). This throws:

DOMException: AudioContext.createMediaStreamSource: Connecting AudioNodes from AudioContexts with different sample-rate is currently not supported.

A secondary issue: the .catch() handler calls this.Microphone_StopRecording(deviceName), but this doesn't refer to the library object in Emscripten merged functions, resulting in:

TypeError: this.Microphone_StopRecording is not a function

Suggested fix

1. Don't force sampleRate on the AudioContext — let the browser pick the native rate: const audioContext = new AudioContext();
2. The C# RecordingManager already handles resampling via ClipData.InputSampleRate / OutputSampleRate.
3. Use the Emscripten global _Microphone_StopRecording(deviceName) instead of this.Microphone_StopRecording(deviceName) in the catch handler.

Additional note

GetDeviceCaps on WebGL (line 332-333 of Microphone.cs) is hardcoded to 44100 and ignores the actual maxFrequency/minFrequency values that the .jspre already reads from device.getCapabilities().sampleRate. Now that Firefox supports MediaStreamTrack.getCapabilities(), these values could be surfaced to C# instead of being hardcoded.

[StephenHodgson]

@Zarbuz be sure to format your copy/paste from gpt lol.

Feel free to open a PR to fix. I don't have time to make this adjustment.