Is it possible to access a frame at a particular offset in a video using a constant time O(1) operation, similar to the constant time random access of an array by index? If so, how can this be achieved in OpenCV 2.4.9?
Hi,
I remember when learning OpenCV I did an example with the old C API that would allow the video to jump to a frame using the track bar; it used
cvSetCaptureProperty(capture, CV_CAP_PROP_POS_FRAMES, frame_nmber)
you can see the documentation under VideoCapture::set with this link and with C++ should look something like this:
capture.set(CV_CAP_PROP_POS_FRAMES, frame_number);
Is this operation O(n)? i.e. do you have to walk through each of the frames from the beginning of the video in order to move to another frame with trackbar?
Using your notation it will be O.set(CV_CAP_PROP_POS_FRAMES, n), and you can call it at the start. From there you can either step through the video using n or as you would normally.
Asked: 2014-09-29 21:32:02 -0600
Seen: 1,041 times
Last updated: Sep 29 '14
