There is a '.srn file' video option. A .srn file is used to add closed captions to a video. https://support.google.com/youtube/answer/2734698?hl=en I checked it, and found that I now had a .ASS file for every video clip. Searching for ".ASS file" returns a lot of results that are not related to closed captions! Even if you don't use the subtitles there is a lot of human-readable information in the .ASS file.