/// <summary>Create MP3FileWriter to write to supplied stream</summary>
/// <param name="outStream">Stream to write encoded data to</param>
/// <param name="format">Input Genode.Audio.WavFormat</param>
/// <param name="bitRate">Output bit rate in kbps</param>
/// <param name="id3">Optional ID3 data block</param>
public LameMP3FileWriter(Stream outStream, Cgen.Audio.WavFormat format, int bitRate, int channels = 2, int sampleRate = 44100, ID3TagData id3 = null)
: base()
{
// sanity check
if (outStream == null)
{
throw new ArgumentNullException("outStream");
}
// select encoder function that matches data format
if (format == Cgen.Audio.WavFormat.PCM)
{
if (channels == 1)
{
_encode = encode_pcm_16_mono;
}
else
{
_encode = encode_pcm_16_stereo;
}
}
else
{
if (channels == 1)
{
_encode = encode_float_mono;
}
else
{
_encode = encode_float_stereo;
}
}
// Set base properties
this.inputFormat = format;
this.outStream = outStream;
this.disposeOutput = false;
// Allocate buffers based on sample rate
this.channels = channels;
this.inBuffer = new ArrayUnion(sampleRate * channels * 2);
this.outBuffer = new byte[sampleRate * 5 / 4 + 7200];
// Initialize lame library
this._lame = new Lame.Wrapper.LibMp3Lame();
this._lame.InputSampleRate = sampleRate;
this._lame.NumChannels = channels;
this._lame.BitRate = bitRate;
if (id3 != null)
{
ApplyID3Tag(id3);
}
this._lame.InitParams();
}
/// <summary>Setup ID3 tag with supplied information</summary>
/// <param name="tag">ID3 data</param>
private void ApplyID3Tag(ID3TagData tag)
{
if (tag == null)
{
return;
}
// Apply standard ID3 fields
if (!string.IsNullOrEmpty(tag.Title))
{
_lame.ID3SetTitle(tag.Title);
}
if (!string.IsNullOrEmpty(tag.Artist))
{
_lame.ID3SetArtist(tag.Artist);
}
if (!string.IsNullOrEmpty(tag.Album))
{
_lame.ID3SetAlbum(tag.Album);
}
if (!string.IsNullOrEmpty(tag.Year))
{
_lame.ID3SetYear(tag.Year);
}
if (!string.IsNullOrEmpty(tag.Comment))
{
_lame.ID3SetComment(tag.Comment);
}
if (!string.IsNullOrEmpty(tag.Genre))
{
_lame.ID3SetGenre(tag.Genre);
}
if (!string.IsNullOrEmpty(tag.Track))
{
_lame.ID3SetTrack(tag.Track);
}
// Apply standard ID3 fields that are not directly supported by LAME
if (!string.IsNullOrEmpty(tag.Subtitle))
{
_lame.ID3SetFieldValue(string.Format("TIT3={0}", tag.Subtitle));
}
if (!string.IsNullOrEmpty(tag.AlbumArtist))
{
_lame.ID3SetFieldValue(string.Format("TPE2={0}", tag.AlbumArtist));
}
// Add user-defined tags if present
// NB: LAME handles the replacement of duplicates.
if (tag.UserDefinedTags?.Length > 0)
{
foreach (var userDefinedTag in tag.UserDefinedTags)
{
_lame.ID3SetFieldValue(string.Format("TXXX={0}", userDefinedTag));
}
}
// Set the album art if supplied and within size limits
if (tag.AlbumArt?.Length > 0 && tag.AlbumArt.Length < 131072)
{
_lame.ID3SetAlbumArt(tag.AlbumArt);
}
}
/// <summary>Create MP3FileWriter to write to a file on disk</summary>
/// <param name="outFileName">Name of file to create</param>
/// <param name="format">Input Genode.Audio.WavFormat</param>
/// <param name="bitRate">Output bit rate in kbps</param>
/// <param name="id3">Optional ID3 data block</param>
public LameMP3FileWriter(string outFileName, Cgen.Audio.WavFormat format, int bitRate, int channels = 2, int sampleRate = 44100, ID3TagData id3 = null)
: this(File.Create(outFileName), format, bitRate, channels, sampleRate, id3)
{
this.disposeOutput = true;
}