Podcast Producer 2 has a really neat tool to automatically create a chapter marker each time a slide is changed in a screen recording of a powerpoint or other presentation. It does that by detecting the change between images, with some boundaries.
The default settings are a bit too aggressive in my opinion – more than a few times I’ve ended up with hundreds of chapter markers in a presentation that only consisted of a few slides. Also, if you’re using an Epiphan screen recorder instead of the podcast producer screencapture tool, you’re likely to have additional noise in the feed which could confused it.
Luckily, you can override the default settings. Chapterization takes advantage of a tool called ‘chapterize’ that lives in /usr/libexec/podcastproducer/. What I’d suggest doing is creating a few sample recordings in your typical environment and then playing with chapterize switches to find the right combination.
Chapterize adds chapters to the movie itself, rather than creating a copy, so you’ll want to backup your file before running it. You can run the command directly to see all of the switches.
I’m working with 1024×768 screen recordings, and I found that bumping up the –reduce ratio number to 8 or 12 substantially reduces the false positives.
Once you’ve found the right combination of settings, you’ll want to modify /usr/lib/podcastproducer/actions/pip.rb, chapterize.rb and qtimport.rb – just search the file for chapterize, it should be pretty self explanatory.