[FFmpeg-user] here's a youtube to show what i mean

[Stefan Scott Alexander]

I uploaded the AVI that I'm trying to process - it's here on YouTube:

http://www.youtube.com/watch?v=lC6uA5xf6D4

I don't want to output another video -
I just want to output a list of all the frames which are different from the
preceding frame
(the list could be either timestamps, or frame numbers).

This is a very simple video - just text.

It's a video screen capture of a computer running speech synthesis software.

Notice how the highlight on each word in the text is perfectly synchronized
with the speech.
The word currently being spoken = the word currently being highlighted.

So I whenever the highlight "jumps" to the next word,
that's the frame number (or timestamp) I want to output to a text file.

Can ffmpeg do this?

I was thinking I could use showinfo and checksum... If two frames are
different, they should have a different checksum.

So maybe I could use showinfo and output all the frames, and all the
checksums.
Then use another program to process this text file, to find which frames had
a different checksum from the preceding frame.

I know this is also called "scene change detection" in video applications.
This case should be really simple, because there's almost nothing moving in
the video -
only the highlight moves.