public AudioMetadata ReadMetadata(Stream stream)
{
var mp4 = new Mp4Model(stream);
if (mp4.DescendToAtom("moov", "udta", "meta", "ilst"))
{
return(new IlstAtomToMetadataAdapter(mp4, mp4.GetChildAtomInfo()));
}
throw new AudioUnsupportedException("No ilst atom found.");
}
public AudioInfo ReadAudioInfo(Stream stream)
{
try
{
var mp4 = new Mp4Model(stream);
mp4.DescendToAtom("moov", "trak", "mdia", "minf", "stbl", "stts");
var stts = new SttsAtom(mp4.ReadAtom(mp4.CurrentAtom));
var sampleCount = stts.PacketCount * stts.PacketSize;
mp4.DescendToAtom("moov", "trak", "mdia", "minf", "stbl", "stsd", "mp4a", "esds");
var esds = new EsdsAtom(mp4.ReadAtom(mp4.CurrentAtom));
if (esds.IsAac)
{
mp4.Reset();
return(AudioInfo.CreateForLossy("AAC", esds.Channels, (int)esds.SampleRate, sampleCount,
CalculateBitRate(mp4.GetChildAtomInfo().Single(atom =>
atom.FourCc.Equals("mdat", StringComparison.Ordinal)).Size,
sampleCount,
esds.SampleRate)));
}
// Apple Lossless files have their own atom for storing audio info
if (!mp4.DescendToAtom("moov", "trak", "mdia", "minf", "stbl", "stsd", "alac"))
{
throw new AudioUnsupportedException("Only AAC and ALAC MP4 streams are supported.");
}
var alac = new AlacAtom(mp4.ReadAtom(mp4.CurrentAtom));
return(AudioInfo.CreateForLossless(
"ALAC",
alac.Channels,
alac.BitsPerSample,
(int)alac.SampleRate,
sampleCount));
}
catch (EndOfStreamException e)
{
throw new AudioInvalidException(e.Message);
}
}
internal IlstAtomToMetadataAdapter(
[NotNull] Mp4Model mp4,
[NotNull, ItemNotNull] IEnumerable <AtomInfo> atoms)
{
foreach (var atom in atoms)
{
var atomData = mp4.ReadAtom(atom);
// ReSharper disable once SwitchStatementMissingSomeCases
switch (atom.FourCc)
{
case "©nam":
Title = new TextAtom(atomData).Value;
break;
case "©ART":
Artist = new TextAtom(atomData).Value;
break;
case "©alb":
Album = new TextAtom(atomData).Value;
break;
case "aART":
AlbumArtist = new TextAtom(atomData).Value;
break;
case "©wrt":
Composer = new TextAtom(atomData).Value;
break;
case "©gen":
Genre = new TextAtom(atomData).Value;
break;
case "©cmt":
Comment = new TextAtom(atomData).Value;
break;
case "©day":
// The ©day atom may contain a full date, or only the year:
var dayAtom = new TextAtom(atomData);
if (DateTime.TryParse(dayAtom.Value, CultureInfo.CurrentCulture,
DateTimeStyles.NoCurrentDateDefault, out var result))
{
Day = result.Day.ToString(CultureInfo.InvariantCulture);
Month = result.Month.ToString(CultureInfo.InvariantCulture);
Year = result.Year.ToString(CultureInfo.InvariantCulture);
}
else
{
Year = dayAtom.Value;
}
break;
case "trkn":
var trackNumberAtom = new TrackNumberAtom(atomData);
TrackNumber = trackNumberAtom.TrackNumber.ToString(CultureInfo.InvariantCulture);
if (trackNumberAtom.TrackCount > 0)
{
TrackCount = trackNumberAtom.TrackCount.ToString(CultureInfo.InvariantCulture);
}
break;
case "covr":
CoverArt = new CoverAtom(atomData).Value;
break;
}
}
}
