To capture frames of html animations and stitch them into video, I was about to use Timecut (available from npm). However the result is not crisp videos - the capture is rather fuzzy for some reason.
What other terminal app would you reccomend for capturing html animations? Main goal is crisp output!
If I understand the question correctly you are looking for a way to record your screen with an application that can be run from the commandline.
I would use ffmpeg which is available from brew more details on screen recording using ffmpeg on MacOS can be found in this answer and on the ffmpeg wiki.
Remember that the resolution/"crispiness" of the video you record will be limited by your desktop resolution. Zooming in on the content you want to record might help if it's possible.