(05.08.2021, 05:24)Selur Wrote: Will think about it. Seems like a lot of hassle. 
Cu Selur
Think I might have found a solution with
almost no hassle
Was looking through the Documentation for mkvmerge and realised that Hybrid doesn't actually do anything to change the original attachments in any way (unless there's an option to change a cover picture I've missed?): why not just create an mkv file with
only attachments:
mkvmerge -o Attachments.mkv -A -D -S -B -T --no-chapters --no-global-tags Original.mkv
Then simply
append it to the Hybrid processed file at the end of encoding:
mkvmerge -o Final_filename.mkv Processed_Hybrid_file.mkv + attachments.mkv
Then delete the processed & attachment files... Done?
Since matroska uses UID the attachment shouldn't conflict with anything Hybrid might have wrote.
Should neatly bypass having to deal with processing fonts, etc all together.
Did a quick test myself an it
seems to work fine with no side effects that I can spot.
Am I overlooking anything?