pcmToWave method

Future<void> pcmToWave({

required String inputFile,
required String outputFile,
int numChannels = 1,
int sampleRate = 16000,
Codec codec = FSCodec.Codec.pcm16,

})

Converts a raw PCM file to a WAVE file.

Add a WAVE header in front of the PCM data This verb is usefull to convert a Raw PCM file to a Wave file. It adds a Wave envelop to the PCM file, so that the file can be played back with startPlayer().

Note: the parameters numChannels and sampleRate are mandatory, and must match the actual PCM data.

See here a discussion about Raw PCM and WAVE file format.

Parameters

inputFile: is a file path to your input file
outputFile: is a path to your output file
numChannels: is the number of channels of your file
sampleRate is the sample rate of your data
codec is either FSCodec.Codec.pcm16 or FSCodec.Codec.pcmFloat32

Example

FlutterSoundHelper().pcmToWave (
    inputFile: 'foo.pcm',
    outputFile: 'foo.wav',
    numChannels: 2 // stereo
    samplerate: 48000,
    codec: FSCodec.Codec.pcm16
 );

Implementation

Future<void> pcmToWave({
  required String inputFile,
  required String outputFile,
  int numChannels = 1,
  int sampleRate = 16000,
  FSCodec.Codec codec = FSCodec.Codec.pcm16,
}) async {
  if (codec != FSCodec.Codec.pcm16 && codec != FSCodec.Codec.pcmFloat32) {
    throw (Exception('Bad codec'));
  }
  var filIn = File(inputFile);
  var filOut = File(outputFile);
  var size = filIn.lengthSync();
  logger.i(
    'pcmToWave() : input = $inputFile,  output = $outputFile,  size = $size',
  );
  var sink = filOut.openWrite();

  var header = WaveHeader(
    codec == FSCodec.Codec.pcm16
        ? WaveHeader.formatInt
        : WaveHeader.formatFloat,
    numChannels = numChannels, //
    sampleRate = sampleRate,
    codec == FSCodec.Codec.pcm16 ? 16 : 32, // 16 bits per byte
    size, // total number of bytes
  );
  header.write(sink);
  await filIn.open();
  var buffer = filIn.readAsBytesSync();
  sink.add(buffer.toList());
  await sink.close();
}