private long GetLength()
{
// http://msdn.microsoft.com/en-gb/library/windows/desktop/dd389281%28v=vs.85%29.aspx#getting_file_duration
var variantValue = reader.GetPresentationAttribute(SourceReaderIndex.MediaSource, PresentationDescriptionAttributeKeys.Duration);
var lengthInBytes = (variantValue * waveFormat.AverageBytesPerSecond) / 10000000L;
return(lengthInBytes);
}
private long GetLength(SourceReader reader)
{
lock (_lockObj)
{
try
{
if (reader == null)
{
return(0);
}
var value =
reader.GetPresentationAttribute(SourceReaderIndex.MediaSource,
MediaFoundationAttributes.MF_PD_DURATION);
//bug: still, depending on the decoder, this returns imprecise values.
return(NanoSecond100UnitsToBytes((long)(ulong)value.Value));
}
catch (Exception)
{
return(0);
}
}
}
private void Initialize(SourceReader reader)
{
// Invalidate selection for all streams
reader.SetStreamSelection(SourceReaderIndex.AllStreams, false);
// Select only audio stream
reader.SetStreamSelection(SourceReaderIndex.FirstAudioStream, true);
// Get the media type for the current stream.
using (var mediaType = reader.GetNativeMediaType(SourceReaderIndex.FirstAudioStream, 0))
{
var majorType = mediaType.Get(MediaTypeAttributeKeys.MajorType);
if (majorType != MediaTypeGuids.Audio)
throw new InvalidOperationException("Input stream doesn't contain an audio stream.");
}
// Set the type on the source reader to use PCM
using (var partialType = new MediaType())
{
partialType.Set(MediaTypeAttributeKeys.MajorType, MediaTypeGuids.Audio);
partialType.Set(MediaTypeAttributeKeys.Subtype, AudioFormatGuids.Pcm);
reader.SetCurrentMediaType(SourceReaderIndex.FirstAudioStream, partialType);
}
// Retrieve back the real media type
using (var realMediaType = reader.GetCurrentMediaType(SourceReaderIndex.FirstAudioStream))
{
int sizeRef;
WaveFormat = realMediaType.ExtracttWaveFormat(out sizeRef);
}
Duration = new TimeSpan(reader.GetPresentationAttribute(SourceReaderIndex.MediaSource, PresentationDescriptionAttributeKeys.Duration));
}