m4b-tool VS video-everyday

I’ve been using https://github.com/sandreas/m4b-tool for years to combine files into m4b, add cover and metadata. I also use iOS and prologue for listening.

MP3Merge, m4b-tool. This one is interesting for iOS users.

Look into m4btool (https://github.com/sandreas/m4b-tool). Audiobookbinder increases the m4b filesize. Followed this post for my own purposes: https://apple.stackexchange.com/questions/426094/convert-multiple-mp3-files-or-single-m4a-into-m4b-with-ffmpeg-and-afconvert

M4B-tool which wraps ffmpeg might be your best bet if you are planning on converting m4b’s.

I battled with this a lot with https://github.com/umaar/video-everyday and still haven't found a better solution.

What I don't understand is, how can professional video editing tools trim accurately (and very quickly)? What are they doing differently to ffmpeg?

If do things the "fast way" with ffmpeg, the exported video has random black frames which I think is related to the keyframe issue you mention. If I do things the "slow way" (e.g. accurately) with ffmpeg, it takes a huge amount of time (at least with large 4k videos). But I don't understand how I can drop that same 4k video into Screenflow, trim 1 second out of it and export it in a matter of seconds.