/// <summary>
/// Gets an attribute from the underlying media source.
/// </summary>
/// <param name="sourceReader">A valid IMFSourceReader instance.</param></param>
/// <param name="streamIndex">The streamIndex to query.</param>
/// <param name="mediaTypeIndex">The zero-based index of the media type to retrieve.</param>
/// <param name="mediaType">Receives an instance of the IMFMediaType interface.</param>
/// <returns>If this function succeeds, it returns the S_OK member. Otherwise, it returns another HResult's member that describe the error.</returns>
public static HResult GetPresentationAttribute(this IMFSourceReader sourceReader, SourceReaderFirstStreamOrMediaSource streamIndex, Guid guidAttribute, PropVariant attribute)
{
if (sourceReader == null)
{
throw new ArgumentNullException("sourceReader");
}
return(sourceReader.GetPresentationAttribute((int)streamIndex, guidAttribute, attribute));
}
/// <summary>
/// Queries the underlying media source or decoder for an interface.
/// </summary>
/// <typeparam name="T">The COM interface being requested.</typeparam></typeparam>
/// <param name="sourceReader">A valid IMFSourceReader instance.</param></param></param>
/// <param name="streamIndex">The streamIndex or object to query.</param>
/// <param name="guidService">A service identifier GUID.</param>
/// <param name="service">Receives an instance of the requested interface.</param>
/// <returns>If this function succeeds, it returns the S_OK member. Otherwise, it returns another HResult's member that describe the error.</returns>
public static HResult GetServiceForStream <T>(this IMFSourceReader sourceReader, SourceReaderFirstStreamOrMediaSource streamIndex, Guid guidService, out T service) where T : class
{
if (sourceReader == null)
{
throw new ArgumentNullException("sourceReader");
}
Type typeOfT = typeof(T);
if (!typeOfT.IsInterface)
{
throw new ArgumentOutOfRangeException("T", "T must be a COM visible interface.");
}
object tmp;
HResult hr = sourceReader.GetServiceForStream((int)streamIndex, guidService, typeOfT.GUID, out tmp);
service = hr.Succeeded() ? tmp as T : null;
return(hr);
}
