writeWavBytes function

Uint8List writeWavBytes({ required Iterable<FlacFrame> frames, required int sampleRate, required int channels, required int bitsPerSample, })

Serialises decoded FLAC samples as a RIFF/WAVE byte buffer.

frames are the decoded audio frames, sampleRate and channels come from STREAMINFO, and bitsPerSample is the FLAC stream's bit depth. The WAV output uses a sample width rounded up to the nearest whole byte: 1–8 → 8-bit unsigned, 9–16 → 16-bit signed LE, 17–24 → 24-bit signed LE, 25–32 → 32-bit signed LE.

Implementation

Uint8List writeWavBytes({
  required Iterable<FlacFrame> frames,
  required int sampleRate,
  required int channels,
  required int bitsPerSample,
}) {
  final outBps = ((bitsPerSample + 7) ~/ 8) * 8;
  final frameList = frames is List<FlacFrame> ? frames : frames.toList();
  final builder = BytesBuilder(copy: false);
  for (final f in frameList) {
    builder.add(frameToWavPcmBytes(f, outBps));
  }
  final pcm = builder.takeBytes();

  final dataSize = pcm.length;
  final header = writeWavHeaderBytes(
    dataSize: dataSize,
    sampleRate: sampleRate,
    channels: channels,
    bitsPerSample: outBps,
  );
  final out = Uint8List(header.length + dataSize);
  out.setRange(0, header.length, header);
  out.setRange(header.length, header.length + dataSize, pcm);
  return out;
}