I think you'd be better off using either GSreamer or ffmpeg, or if you're on Windows, DirectShow. These libs can handle both audio and video, and should have some kind of a Multiplexer to allow you to mix video and audio properly.
But if you really want to do this using Opencv, you should be able to use VideoCapture
to get the frame rate, have you tried using this?
fps = cv.GetCaptureProperty(vc, CV_CAP_PROP_FPS)
Another way would be to estimate fps as number of frames divided by duration:
nFrames = cv.GetCaptureProperty(vc, CV_CAP_PROP_FRAME_COUNT)
cv.SetCaptureProperty(vc, CV_CAP_PROP_POS_AVI_RATIO, 1)
duration = cv.GetCaptureProperty(vc, CV_CAP_PROP_POS_MSEC)
fps = 1000 * nFrames / duration;
I'm not sure I understand what you were trying to do here:
before_read = time.time()
rval, frame = vc.read()
after_read = time.time()
It seems to me that doing after_read - before_read
only measures how long it took for OpenCV to load the next frame, it doesn't measure the fps. OpenCV is not trying to do playback, it's only loading frames and it'll try to do so the fastest it can and I think there's no way to configure that. I think that putting a waitKey(1/fps)
after displaying each frame will achieve what you're looking for.