matt051 I never tried byoj.
I find that for many videos/scripts there are huge parts I won't watch more than once, and I want to keep a selection of my own favourite clips locally, and save on disk space.
This is how I get the same result. It requires a computer, and ffmpeg (free). Download the video, and use ffmpeg to cut out the desired clip. Also, if desired you can then merge several clips back into one. Just google something like "ffmpeg+cut+and+merge" to get the exact commands required.
As a sidenote, it is also pretty easy to use a funscript editor to then cut and paste segments of existing scripts and line them up to the action in the clips.