public AudioInfo ReadAudioInfo(Stream stream)
{
using (var reader = new FrameReader(stream))
try
{
var frameHeader = ReadFrameHeader(reader);
// Frame count is found in the optional Xing (most common) or VBRI header
var optionalHeader = ReadXingHeader(reader, frameHeader);
if (optionalHeader.Incomplete)
{
optionalHeader = ReadVbriHeader(reader);
}
return(AudioInfo.CreateForLossy(
"MP3",
frameHeader.Channels,
frameHeader.SampleRate,
optionalHeader.FrameCount * frameHeader.SamplesPerFrame,
DetermineBitRate(frameHeader, optionalHeader)));
}
catch (EndOfStreamException e)
{
// If a frame sync couldn't be located, this isn't an MP3
throw new AudioInvalidException(e.Message);
}
}
public void BitRateIsSerialized()
{
var formatter = new BinaryFormatter();
using (var stream = new MemoryStream())
{
formatter.Serialize(stream, AudioInfo.CreateForLossy("Test", 2, 44100, 0, 1000));
stream.Position = 0;
Assert.Equal(1000, ((AudioInfo)formatter.Deserialize(stream)).BitRate);
}
}
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);
}
}
public unsafe AudioInfo ReadAudioInfo(Stream stream)
{
OggStream?oggStream = null;
SafeNativeMethods.VorbisCommentInit(out var vorbisComment);
#if NETSTANDARD2_0
var buffer = ArrayPool <byte> .Shared.Rent(4096);
#else
Span <byte> buffer = stackalloc byte[4096];
#endif
try
{
using (var sync = new OggSync())
using (var decoder = new VorbisDecoder())
{
OggPage page;
do
{
// Read from the buffer into a page
while (!sync.PageOut(out page))
{
#if NETSTANDARD2_0
var bytesRead = stream.Read(buffer, 0, buffer.Length);
#else
var bytesRead = stream.Read(buffer);
#endif
if (bytesRead == 0)
{
throw new AudioInvalidException("No Ogg stream was found.");
}
var nativeBuffer = new Span <byte>(sync.Buffer(bytesRead).ToPointer(), bytesRead);
#if NETSTANDARD2_0
buffer.AsSpan().Slice(0, bytesRead).CopyTo(nativeBuffer);
#else
buffer.Slice(0, bytesRead).CopyTo(nativeBuffer);
#endif
sync.Wrote(bytesRead);
}
oggStream ??= new(SafeNativeMethods.OggPageSerialNo(page));
oggStream.PageIn(page);
while (oggStream.PacketOut(out var packet))
{
if (!SafeNativeMethods.VorbisSynthesisIdHeader(packet))
{
throw new AudioUnsupportedException("Not a Vorbis stream.");
}
decoder.HeaderIn(vorbisComment, packet);
var info = decoder.GetInfo();
return(AudioInfo.CreateForLossy(
"Vorbis",
info.Channels,
#if WINDOWS
info.Rate,
GetFinalGranulePosition(oggStream.SerialNumber, stream),
Math.Max(info.BitRateNominal, 0)));
#else
(int)info.Rate,
GetFinalGranulePosition((int)oggStream.SerialNumber, stream),
Math.Max((int)info.BitRateNominal, 0));
#endif
}
} while (!SafeNativeMethods.OggPageEos(page));
throw new AudioInvalidException("The end of the Ogg stream was reached without finding a header.");
}
}
finally
{
#if NETSTANDARD2_0
ArrayPool <byte> .Shared.Return(buffer);
#endif
SafeNativeMethods.VorbisCommentClear(ref vorbisComment);
oggStream?.Dispose();
}
}
public void BitRateNegativeThrowsException()
{
Assert.Throws <AudioInvalidException>(() => AudioInfo.CreateForLossy("Test", 2, 44100, 0, -1));
}