Description

Some of our iOS users intermittently encounter the following error when starting audio recording:

Failed to open file for writing: Invalid input format: sampleRate and channelCount must be greater than 0

This occurs despite the audio session being activated successfully (confirmed via our logs — setAudioSessionActivity(true) returns true).

Reproduction

Below is a simplified version of our recording flow:

AudioManager.setAudioSessionOptions({
  iosCategory: "playAndRecord",
  iosMode: "default",
  iosOptions: ["defaultToSpeaker", "allowBluetoothHFP"],
});

await AudioManager.setAudioSessionActivity(true); // Returns true per our logs

// Delay to prevent empty voice note issue we observed previously
await delay(300);

recorder.enableFileOutput({
  format: FileFormat.M4A,
  preset: FilePreset.High,
});

const result = recorder.start({ fileNameOverride: `overridden_name_${Date.now()}` });
if (result.status === "error") {
  throw new Error(result.message); // <-- Throws the error above
}

Environment

• react-native-audio-api: 0.11.7
• react-native: 0.79.6

Observations

• The error is intermittent — it does not happen on every recording attempt.
• The audio session is confirmed active before recorder.start() is called.
• We already include a 300ms delay between session activation and recording to work around a separate issue with empty recordings.

Questions

• Is there a known scenario where sampleRate or channelCount could be 0 even after a successful setAudioSessionActivity(true) call?
• Is there anything incorrect or missing in our implementation?

Any guidance would be appreciated. Thanks!