void ReportGetSampleCompleted(IMediaSample sample)
{
ArraySegment<byte> buf = sample.GetBuffer<byte> ();
position += ToTick (sample.Duration);
var s = new MediaStreamSample (media_desc, new MemoryStream (buf.Array), buf.Offset, buf.Count, position, empty_atts);
this.ReportGetSampleCompleted (s);
}