private static IntPtr GetCompressor(VfwApi.BitmapInfoHeader inBitmapInfo, VfwApi.BitmapInfoHeader outBitmapInfo, out VfwApi.CompressorInfo compressorInfo)
{
// Using ICLocate is time-consuming. Besides, it does not clean up something, so the process does not terminate on exit.
// Instead open a specific codec and query it for needed features.
var compressorHandle = VfwApi.ICOpen((uint)KnownFourCCs.CodecTypes.Video, outBitmapInfo.Compression, VfwApi.ICMODE_COMPRESS);
if (compressorHandle != IntPtr.Zero)
{
var inHeader = inBitmapInfo;
var outHeader = outBitmapInfo;
var result = VfwApi.ICSendMessage(compressorHandle, VfwApi.ICM_COMPRESS_QUERY, ref inHeader, ref outHeader);
if (result == VfwApi.ICERR_OK)
{
var infoSize = VfwApi.ICGetInfo(compressorHandle, out compressorInfo, Marshal.SizeOf(typeof(VfwApi.CompressorInfo)));
if (infoSize > 0 && compressorInfo.SupportsFastTemporalCompression)
{
return(compressorHandle);
}
}
VfwApi.ICClose(compressorHandle);
}
compressorInfo = new VfwApi.CompressorInfo();
return(IntPtr.Zero);
}
private int GetMaxEncodedSize()
{
var inHeader = inBitmapInfo;
var outHeader = outBitmapInfo;
return(VfwApi.ICSendMessage(compressorHandle, VfwApi.ICM_COMPRESS_GET_SIZE, ref inHeader, ref outHeader));
}
private void StartCompression()
{
var inHeader = inBitmapInfo;
var outHeader = outBitmapInfo;
var result = VfwApi.ICSendMessage(compressorHandle, VfwApi.ICM_COMPRESS_BEGIN, ref inHeader, ref outHeader);
CheckICResult(result);
needEnd = true;
framesFromLastKey = keyFrameRate;
}
private void InitCompressFramesInfo(double fps, int frameCount)
{
var info = new VfwApi.CompressFramesInfo
{
StartFrame = 0,
FrameCount = frameCount,
Quality = quality,
KeyRate = keyFrameRate,
};
AviUtils.SplitFrameRate((decimal)fps, out info.FrameRateNumerator, out info.FrameRateDenominator);
var result = VfwApi.ICSendMessage(compressorHandle, VfwApi.ICM_COMPRESS_FRAMES_INFO, ref info, Marshal.SizeOf(typeof(VfwApi.CompressFramesInfo)));
CheckICResult(result);
}
private void EndCompression()
{
var result = VfwApi.ICSendMessage(compressorHandle, VfwApi.ICM_COMPRESS_END, IntPtr.Zero, IntPtr.Zero);
CheckICResult(result);
}