// Retrieve capabilities of a video device
internal VideoCapabilities( IAMStreamConfig videoStreamConfig, int index )
{
AMMediaType mediaType = null;
VideoStreamConfigCaps caps = new VideoStreamConfigCaps( );
try
{
// retrieve capabilities struct at the specified index
int hr = videoStreamConfig.GetStreamCaps( index, out mediaType, caps );
if ( hr != 0 )
Marshal.ThrowExceptionForHR( hr );
if ( mediaType.FormatType == FormatType.VideoInfo )
{
VideoInfoHeader videoInfo = (VideoInfoHeader) Marshal.PtrToStructure( mediaType.FormatPtr, typeof( VideoInfoHeader ) );
FrameSize = new Size( videoInfo.BmiHeader.Width, videoInfo.BmiHeader.Height );
BitCount = videoInfo.BmiHeader.BitCount;
AverageFrameRate = (int) ( 10000000 / videoInfo.AverageTimePerFrame );
MaximumFrameRate = (int) ( 10000000 / caps.MinFrameInterval );
}
else if ( mediaType.FormatType == FormatType.VideoInfo2 )
{
VideoInfoHeader2 videoInfo = (VideoInfoHeader2) Marshal.PtrToStructure( mediaType.FormatPtr, typeof( VideoInfoHeader2 ) );
FrameSize = new Size( videoInfo.BmiHeader.Width, videoInfo.BmiHeader.Height );
BitCount = videoInfo.BmiHeader.BitCount;
AverageFrameRate = (int) ( 10000000 / videoInfo.AverageTimePerFrame );
MaximumFrameRate = (int) ( 10000000 / caps.MinFrameInterval );
}
else
{
throw new ApplicationException( "Unsupported format found." );
}
// ignore 12 bpp formats for now, since it was noticed they cause issues on Windows 8
// TODO: proper fix needs to be done so ICaptureGraphBuilder2::RenderStream() does not fail
// on such formats
if ( BitCount <= 12 )
{
throw new ApplicationException( "Unsupported format found." );
}
}
finally
{
if ( mediaType != null )
mediaType.Dispose( );
}
}
// Set resolution for the specified stream configuration
private void SetResolution( IAMStreamConfig streamConfig, VideoCapabilities resolution )
{
if ( resolution == null )
{
return;
}
// iterate through device's capabilities to find mediaType for desired resolution
int capabilitiesCount = 0, capabilitySize = 0;
AMMediaType newMediaType = null;
VideoStreamConfigCaps caps = new VideoStreamConfigCaps( );
streamConfig.GetNumberOfCapabilities( out capabilitiesCount, out capabilitySize );
for ( int i = 0; i < capabilitiesCount; i++ )
{
try
{
VideoCapabilities vc = new VideoCapabilities( streamConfig, i );
if ( resolution == vc )
{
if ( streamConfig.GetStreamCaps( i, out newMediaType, caps ) == 0 )
{
break;
}
}
}
catch
{
}
}
// set the new format
if ( newMediaType != null )
{
streamConfig.SetFormat( newMediaType );
newMediaType.Dispose( );
}
}
