public static ConversionQuality ConvertToFormat(AudioContent content, ConversionFormat formatType, ConversionQuality quality, string saveToFile)
{
var temporaryOutput = Path.GetTempFileName();
try
{
string ffmpegCodecName, ffmpegMuxerName;
//int format;
switch (formatType)
{
case ConversionFormat.Adpcm:
// ADPCM Microsoft
ffmpegCodecName = "adpcm_ms";
ffmpegMuxerName = "wav";
//format = 0x0002; /* WAVE_FORMAT_ADPCM */
break;
case ConversionFormat.Pcm:
// XNA seems to preserve the bit size of the input
// format when converting to PCM.
if (content.Format.BitsPerSample == 8)
{
ffmpegCodecName = "pcm_u8";
}
else if (content.Format.BitsPerSample == 32 && content.Format.Format == 3)
{
ffmpegCodecName = "pcm_f32le";
}
else
{
ffmpegCodecName = "pcm_s16le";
}
ffmpegMuxerName = "wav";
//format = 0x0001; /* WAVE_FORMAT_PCM */
break;
case ConversionFormat.WindowsMedia:
// Windows Media Audio 2
ffmpegCodecName = "wmav2";
ffmpegMuxerName = "asf";
//format = 0x0161; /* WAVE_FORMAT_WMAUDIO2 */
break;
case ConversionFormat.Xma:
throw new NotSupportedException(
"XMA is not a supported encoding format. It is specific to the Xbox 360.");
case ConversionFormat.ImaAdpcm:
// ADPCM IMA WAV
ffmpegCodecName = "adpcm_ima_wav";
ffmpegMuxerName = "wav";
//format = 0x0011; /* WAVE_FORMAT_IMA_ADPCM */
break;
case ConversionFormat.Aac:
// AAC (Advanced Audio Coding)
// Requires -strict experimental
ffmpegCodecName = "aac";
ffmpegMuxerName = "ipod";
//format = 0x0000; /* WAVE_FORMAT_UNKNOWN */
break;
case ConversionFormat.Vorbis:
// Vorbis
ffmpegCodecName = "libvorbis";
ffmpegMuxerName = "ogg";
//format = 0x0000; /* WAVE_FORMAT_UNKNOWN */
break;
default:
// Unknown format
throw new NotSupportedException();
}
string ffmpegStdout, ffmpegStderr;
int ffmpegExitCode;
do
{
ffmpegExitCode = ExternalTool.Run(
"ffmpeg",
string.Format(
"-y -i \"{0}\" -vn -c:a {1} -b:a {2} -ar {3} -f:a {4} -strict experimental \"{5}\"",
content.FileName,
ffmpegCodecName,
QualityToBitRate(quality),
QualityToSampleRate(quality, content.Format.SampleRate),
ffmpegMuxerName,
temporaryOutput),
out ffmpegStdout,
out ffmpegStderr);
if (ffmpegExitCode != 0)
{
quality--;
}
} while (quality >= 0 && ffmpegExitCode != 0);
if (ffmpegExitCode != 0)
{
throw new InvalidOperationException("ffmpeg exited with non-zero exit code: \n" + ffmpegStdout + "\n" + ffmpegStderr);
}
byte[] rawData;
using (var fs = new FileStream(temporaryOutput, FileMode.Open, FileAccess.Read))
{
rawData = new byte[fs.Length];
fs.Read(rawData, 0, rawData.Length);
}
if (saveToFile != null)
{
using (var fs = new FileStream(saveToFile, FileMode.Create, FileAccess.Write))
fs.Write(rawData, 0, rawData.Length);
}
// Use probe to get the final format and information on the converted file.
AudioFileType audioFileType;
AudioFormat audioFormat;
TimeSpan duration;
int loopStart, loopLength;
ProbeFormat(temporaryOutput, out audioFileType, out audioFormat, out duration, out loopStart, out loopLength);
AudioFormat riffAudioFormat;
byte[] data = StripRiffWaveHeader(rawData, out riffAudioFormat);
// deal with adpcm
if (audioFormat.Format == 2 || audioFormat.Format == 17)
{
// riff contains correct blockAlign
audioFormat = riffAudioFormat;
// fix loopLength -> has to be multiple of sample per block
// see https://msdn.microsoft.com/de-de/library/windows/desktop/ee415711(v=vs.85).aspx
int samplesPerBlock = SampleAlignment(audioFormat);
loopLength = (int)(audioFormat.SampleRate * duration.TotalSeconds);
int remainder = loopLength % samplesPerBlock;
loopLength += samplesPerBlock - remainder;
}
content.SetData(data, audioFormat, duration, loopStart, loopLength);
}
finally
{
ExternalTool.DeleteFile(temporaryOutput);
}
return(quality);
}