/// <summary>
/// Reads the next frame and returns the corresponding buffer.
/// Null is returned if there was nothing to read.
/// </summary>
protected SeeingSharpMediaBuffer ReadFrameInternal()
{
if (m_endReached)
{
return(null);
}
MF.SourceReaderFlags readerFlags;
int dummyStreamIndex;
using (MF.Sample nextSample = m_sourceReader.ReadSample(
MF.SourceReaderIndex.FirstVideoStream,
MF.SourceReaderControlFlags.None,
out dummyStreamIndex,
out readerFlags,
out m_currentPositionLong))
{
// Check for end-of-stream
if (readerFlags == MF.SourceReaderFlags.Endofstream)
{
m_endReached = true;
return(null);
}
// No sample received
if (nextSample == null)
{
return(null);
}
// Reset end-reached flag (maybe the user called SetPosition again..)
m_endReached = false;
// Copy pixel data into target buffer
if (nextSample.BufferCount > 0)
{
return(new SeeingSharpMediaBuffer(nextSample.GetBufferByIndex(0)));
}
}
return(null);
}
/// <summary>
/// Gets the decoded PCM samples. See remarks.
/// </summary>
/// <param name="startingPositionInSeconds">The starting position in seconds.</param>
/// <returns>An enumerator of pointer to PCM decoded data with the same format as returned by <see cref="WaveFormat"/>.</returns>
/// <remarks>
/// This method is only working as a single enumerator at a time.
/// The <see cref="SetSourceStream(System.IO.Stream)"/> must be set before calling <see cref="GetSamples()"/>
/// </remarks>
public IEnumerable <DataPointer> GetSamples(TimeSpan startingPositionInSeconds)
{
// A new reader is setup, so initialize it.
lock (sourceReaderLock)
{
// If the reader was changed
if (nextSourceReader != null)
{
if (sourceReader != null)
{
sourceReader.Dispose();
}
sourceReader = nextSourceReader;
nextSourceReader = null;
}
}
// Make sure that any prior call
CleanupAndDispose();
CheckIfDisposed();
// Set the position
sourceReader.SetCurrentPosition((long)(startingPositionInSeconds.Ticks));
while (true)
{
int streamIndex;
SourceReaderFlags flags;
long time;
CheckIfDisposed();
using (currentSample = sourceReader.ReadSample(SourceReaderIndex.FirstAudioStream, SourceReaderControlFlags.None, out streamIndex, out flags, out time))
{
if ((flags & SourceReaderFlags.Endofstream) != 0)
{
break;
}
CheckIfDisposed();
using (currentBuffer = currentSample.ConvertToContiguousBuffer())
{
int bufferMaxLength;
int bufferCurrentLength;
CheckIfDisposed();
var ptr = currentBuffer.Lock(out bufferMaxLength, out bufferCurrentLength);
yield return(new DataPointer(ptr, bufferCurrentLength));
// Warning, because the yield could never return here, currentBuffer and currentSample should be disposed when disposing this object or when
// calling it again on the GetSamples method.
// In case a Dispose occurred while decoding
if (currentBuffer == null)
{
break;
}
currentBuffer.Unlock();
}
}
}
// They have been disposed, so we can just clear them
currentBuffer = null;
currentSample = null;
}
