public void initialize(iVideoTrack videoTrack, int encodedBuffersCount)
{
// dbgPrintEncodedFormats();
// Determine format of the encoded video
sPixelFormatMP encodedFormat = videoTrack.getEncodedFormat();
// Set format of the first and the only plane of the compressed video.
encodedFormat.numPlanes = 1;
encodedFormat.setPlaneFormat(0, new sPlanePixelFormat()
{
sizeImage = EncodedQueue.encodedVideoBufferSize(videoTrack)
});
// 4.5.1.5. Initialization
// 1. Set the coded format on OUTPUT via VIDIOC_S_FMT()
sStreamDataFormat sdf = new sStreamDataFormat()
{
bufferType = eBufferType.VideoOutputMPlane,
pix_mp = encodedFormat
};
device.file.call(eControlCode.S_FMT, ref sdf);
// Logger.logVerbose( "eControlCode.S_FMT completed OK for encoded format: {0}", sdf.pix_mp );
// 2 Allocate source (bytestream) buffers via VIDIOC_REQBUFS() on OUTPUT
encoded = new EncodedQueue(device, encodedBuffersCount, ref encodedFormat);
// 3 Start streaming on the OUTPUT queue via VIDIOC_STREAMON()
device.startStreaming(eBufferType.VideoOutputMPlane);
// Continue queuing/dequeuing bytestream buffers to/from the OUTPUT queue via VIDIOC_QBUF() and VIDIOC_DQBUF().
// The buffers will be processed and returned to the client in order, until required metadata to configure the CAPTURE queue are found.
// This is indicated by the decoder sending a V4L2_EVENT_SOURCE_CHANGE event with changes set to V4L2_EVENT_SRC_CH_RESOLUTION.
eventSubscription = new EventSubscription(device);
// Linux kernel on Pi4 appears to be too old and does not implement that spec. The event never arrives, while the encoded buffers are stuck in the Queued state.
// For this reason, we have to deal with dynamic resolution changes instead :-(
// WaitForResolution.wait( device, encoded, reader, waitForResolutionTimeout );
}
// Called on decoder thread
void iDecoderEvents.onDynamicResolutionChange()
{
sSelection selection = default;
selection.type = eBufferType.VideoCaptureMPlane;
selection.target = eSelectionTarget.Compose;
device.file.call(eControlCode.G_SELECTION, ref selection);
// Logger.logInfo( "selection: {0}", selection ); // Appears to be correct, i.e. matches what's in the PPS of the video
if (selection.rect != decodedSize.cropRect)
{
throw new ApplicationException($"Linux failed to decode SPS from the video; SPS says the crop rectangle is { decodedSize.cropRect }, Linux decoded as { selection.rect }");
}
sStreamDataFormat sdf = new sStreamDataFormat {
bufferType = eBufferType.VideoCaptureMPlane
};
device.file.call(eControlCode.G_FMT, ref sdf);
Logger.logVerbose("Automatically selected format: {0}", sdf);
decodedPixelFormat = sdf.pix_mp;
colorFormat = sdf.pix_mp.colorFormat();
Logger.logInfo("Dynamic resolution change: {0}", colorFormat);
return;
// The following code causes endless loop of resolution changes, despite nothing being changed, really
// state = eDecoderState.DrainRezChange;
// The setup workflow in that V4L spec is BS, unfortunately :-(
device.stopStreaming(eBufferType.VideoCaptureMPlane);
int decodedBuffersCount = decoded.buffersCount;
decoded.Dispose();
decoded = null;
sImageFormatDescription format = device.findOutputFormat();
Logger.logVerbose("Picked the format \"{0}\", {1}, flags {2}", format.description, format.pixelFormat, format.flags);
// Destroy the old decoded buffers
sRequestBuffers rbDecoded = new sRequestBuffers()
{
type = eBufferType.VideoCaptureMPlane,
memory = eMemory.MemoryMap
};
device.file.call(eControlCode.REQBUFS, ref rbDecoded);
// Fix a few things there
sdf.pix_mp.pixelFormat = ePixelFormat.NV12; // This one is actually pre-selected, prolly because of the initial one we set in the captureSetup method
sdf.pix_mp.quantization = eQuantization.FullRange; // Linux defaults to limited range, not what we want.
device.file.call(eControlCode.S_FMT, ref sdf);
// Logger.logVerbose( "Set format: {0}", sdf );
// Create new set of decoded buffers, same count as before
decoded = new DecodedQueue(device, decodedBuffersCount);
// Finally, resume the video
device.startStreaming(eBufferType.VideoCaptureMPlane);
decoded.enqueueAll();
}
