A problem for capturing frames from .mp4 file with opencv

[wureka]

I know that the default configuration for opencv does not turn on WITH_FFMPEG. And this results in a issue. It will not work when I use VideoCapture in opencv to grab frames from a .mp4 file. videoCapture.open('foo.mp4'); will always return false no matter what fourcc I try.

Well, it is the last thing that I clone javacpp-presets, turn on WITH_FFMPEG flag, and build opencv myself.
Any suggestion ?

[saudet]

Anything wrong with FFmpegFrameGrabber?

[wureka]

Well, FFmpegFrameGrabber is the object of JavaCV. I use javacpp-presets/opencv. They seem to be different.
And for JavaCV, yes, FFmpegFrameGrabber can successfully grab frames from .mp4 files. However, as I reported to you that JavaCV has problems combining the Depthai package
https://github.com/bytedeco/javacpp-presets/issues/1118)

JavaCV could be another solution. But my current code is all based on opencv, so I may need more time to verify the linkage between JavaCV and Depthai and convert to JavaCV's functions.

By the way, does JavaCV support Raspberry PI ?

[saudet]

JavaCV simply uses OpenCV and FFmpeg from the JavaCPP Presets. It doesn't do anything special.