Question

I need to split big video file into smaller pieces by time. Give me your suggestions, please, and if you can some tips for library usage. Thanks.

Answer 1

OpenCV has Python wrappers.

As you’re interested in video IO, have a look at QueryFrame and its related functions there.

In the end, your code will look something like this (completely untested):

import cv

capture = cv.CaptureFromFile(filename)
while Condition1:
    # Need a frame to get the output video dimensions
    frame = cv.RetrieveFrame(capture) # Will return None if there are no frames
    # New video file
    video_out = cv.CreateVideoWriter(output_filenameX,
        CV_FOURCC('M','J','P','G'), capture.fps, frame.size(), 1)
    # Write the frames
    cv.WriteFrame(video_out, frame)
    while Condition2:
        # Will return None if there are no frames
        frame = cv.RetrieveFrame(capture)
        cv.WriteFrame(video_out, frame)

By the way, there are also ways to do this without writing any code.