Date: 2019-02-07 (Reported by Igor)
Author: use-sparingly (2016-08-17)
Description: 	shows GOP structure of video file.
		It use "ffmpeg --show-frames"
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1) copy the file "iframe-probe.py" in the same folder of the video
files to check.

2) change the permission of the file to "execute":
- With Graphic Interface: RMB (Right Mouse Button) over the 
"iframe-probe.py" file and click on Properties-> Permissions tab,
and check on "Allow this file to run as a program".
- Or with command line:
chmod 774 iframe-probe.py

3) type in command line:  
./iframe-probe.py inputfilename.mp4

Where "inputfilename.mp4" is the file name of the video with its extension 
(for example: mp4, mp2, mkv, and so on)

It also create an "output.txt" file in the same folder/directory 
where you can read all the info frames.

The frames may be I, P, B.
