ok so I set "-DBUILD_opencv_videoio=ON" in opencv/platforms/js/build_js.py, then rebuild the js build. The build was successful.
I was hoping libopencv_videoio.a to appear but it is not in opencv/platforms/js/build_wasm/lib/*.a.
So linking to opencv/platforms/js/build_wasm/lib/*.a still has the same missing symbol.
But stepping back, what I want to have is an efficient video format to do some editing on the C++ side. I could load a video on js and then send all the frames as images to C++. Or I could load videos from file using ffmpeg. But I guess the problem would be that many of the functions in opencv’s video module take as input VideoCapture object. To really use opencv library for videos, I may have to use VideoCapture to load video in the first step. Is my assessment accurate?