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();
}
}