Choose FFmpec decoder

[cudawarped]

@TheEnigmist

So there is some problem either with opencv or ffmpeg.

As stated in your other post

Open Video file (.gif/.mov/.webm) with alpha channel

I’m trying to open a video file (.gif / .webm) with alpha channel on it, but always it gives me 3 channels and it displays with a solid background in Qt6. If I open a normal image .png with alpha channel it works correctly. What I’ve done so far is: VideoCapture capture; capture.open(filename, cv::CAP_FFMPEG); capture.set(cv::CAP_PROP_CONVERT_RGB, false); //to force loading alpha channel frameRate = capture.get(cv::CAP_PROP_FPS); capture.get(cv::CAP_PROP_CONVERT_RGB); // gives 0 //in a thread …

the OpenCV FFMpeg backend does not support an alpha channel

opencv/opencv/blob/9aa647068b2eba4a34462927b1878353dfd3df69/modules/videoio/src/cap_ffmpeg_impl.hpp#L1598

Additonaly CAP_PROP_CONVERT_RGB doesn’t have any effect in FFMpeg and if it did I assume it would be to convert from BGR to RGB but I may be wrong.

Out of interest why do you need an alpha channel?