🐛 AudioRecorder Produces 0-Second (Corrupted) Recordings After Updating from v5.2.0 to v6.1.2

[MazenxELGayar]

---

Environment

• OS: Android 12
• Device: Poco X3 NFC
• Flutter SDK: 3.35.4
• Permissions: Microphone (granted)
• Encoders Tested: Opus, AAC LC, WAV

---

Describe the bug

After updating from record 5.2.0 to 6.1.2, the AudioRecorder produces 0-second recordings (corrupted files).
The encoder initializes successfully (AAC LC, Opus, and WAV all tested), but the resulting file contains only headers and no valid audio data.
The file size is around 6–8 KB and reports 0s duration when inspected or played back.

Record configuration used:

RecordConfig(encoder: AudioEncoder.opus)

---

To Reproduce

1. Create a temporary file path:

   final filePath =
       '${tempDir.path}/temp.${DateTime.now().millisecondsSinceEpoch}.opus';

2. Initialize and start the recorder:

   final recorder = AudioRecorder();
   await recorder.start(
     RecordConfig(encoder: AudioEncoder.opus),
     path: filePath,
   );

3. Wait a few seconds.

4. Stop the recorder:

   await recorder.stop();

5. Attempt to play or inspect the recorded file.

   • File size: ~6–8 KB
   • Duration: 0s
   • Appears corrupted

---

Expected behavior

The recorded file should contain valid audio data of the correct (non-zero) duration.

---

Additional context

Encoder logs show successful initialization:

D/CCodec (17780): allocate(c2.android.opus.encoder)
I/CCodecConfig(17780): query failed after returning 9 values (BAD_INDEX)
D/CCodecBufferChannel: [c2.android.opus.encoder#56] start: updating output delay 0

File path is correctly created:

/data/user/0/com.doctor.voice.patientDev/cache/temp.1760713610632.opus

Playback logs show:

! Audio duration is too small 0s — possibly corrupted

Simplified code example:

abstract class BaseRecordingCubit extends Cubit<BaseRecordingState> {
  final AudioRecorder recorder = AudioRecorder();
  String? filePath;

  Future<void> startRecording() async {
    if (await recorder.hasPermission()) {
      filePath =
          '${(await getTemporaryDirectory()).path}/temp.${DateTime.now().millisecondsSinceEpoch}.opus';
      await recorder.start(
        RecordConfig(encoder: AudioEncoder.opus),
        path: filePath!,
      );
    }
  }

  Future<void> stopRecording() async {
    if (await recorder.isRecording()) {
      await recorder.stop();
    }
  }
}

Logs:

V/MediaPlayer(21075): resetDrmState:  mDrmInfo=null ...
D/AudioRecord(21075): set(): inputSource 0, sampleRate 44100, ...
D/AudioManager(21075): dispatching onAudioFocusChange(-1) ...

Workaround:
Downgrading to version 5.2.1 fixes the issue.
Version 6.1.2 consistently produces corrupted (0s) audio files.

---