/* public sBuffersSet allocateEncodedBuffers( int encodedBuffers, ref sPixelFormatMP format )
* {
* sCreateBuffers buffers = new sCreateBuffers()
* {
* count = encodedBuffers,
* memory = eMemory.MemoryMap,
* };
* buffers.format.bufferType = eBufferType.VideoOutputMPlane;
* buffers.format.pix_mp = format;
* Logger.logVerbose( "allocateEncodedBuffers: {0} buffers\n{1}", encodedBuffers, format );
* file.call( eControlCode.CREATE_BUFS, ref buffers );
* return new sBuffersSet( buffers.index, buffers.count );
* } */
/* internal sBuffersSet allocateDecodedBuffers( int decodedBuffersCount, ref VideoTextureDesc desc, ref DmaBuffers dma )
* {
* sCreateBuffers buffers = new sCreateBuffers()
* {
* count = decodedBuffersCount,
* memory = eMemory.MemoryMap,
* };
* buffers.format.bufferType = eBufferType.VideoCaptureMPlane;
*
* sPixelFormatMP pf = default;
* pf.size = desc.lumaSize;
* pf.pixelFormat = ePixelFormat.NV12;
* pf.field = eField.Progressive;
* pf.numPlanes = 2;
*
* sPlanePixelFormat ppf = default;
* ppf.bytesPerLine = dma.luma.stride;
* ppf.sizeImage = dma.luma.stride * desc.lumaSize.cy;
* pf.setPlaneFormat( 0, ppf );
*
* ppf.bytesPerLine = dma.chroma.stride;
* ppf.sizeImage = dma.chroma.stride * desc.chromaSize.cy;
* pf.setPlaneFormat( 1, ppf );
*
* buffers.format.pix_mp = pf;
* file.call( eControlCode.CREATE_BUFS, ref buffers );
* return new sBuffersSet( buffers.index, buffers.count );
* } */
public bool tryGetEvent(out sEvent evt)
{
int res;
unsafe
{
fixed(sEvent *pointer = &evt)
res = LibC.ioctl(file, (uint)eControlCode.DQEVENT, pointer);
}
if (0 == res)
{
// Got an event
return(true);
}
// Got no event, check errno
int errno = Marshal.GetLastWin32Error();
if (errno == LibC.ENOENT)
{
// Undocumented behavior, BTW, kernel.org docs never say the "no events" condition generates ENOENT code.
evt = default;
return(false);
}
string message = NativeErrorMessages.lookupLinuxError(errno);
if (null != message)
{
throw new COMException($"I/O control code DQEVENT failed: { message }", LibC.hresultFromLinux(errno));
}
throw new COMException($"I/O control code DQEVENT failed: undocumented Linux error code { errno }", LibC.hresultFromLinux(errno));
}