Maintaining timecode using -ss trim tool

Question

I'm currently using this FFMPEG script (using "run shell script" in Automator) on QT ProRes files to strip off the first six channels of audio, pass through for audio and video, and trim the first 6.5 seconds off the beginning of the video:

for f in "$@"
do
/usr/local/bin/ffmpeg -ss 6.5 -i "$f" -c:v copy -map 0:0 -c:a copy -map 0:7  "${f%.*}_ST.mov"
done

When I use this script, it successfully trims the file but then moves the original timecode up to the new beginning of the clip. So if 00:59:48:00 was my timecode at the beginning of the original clip, it's now also the starting timecode of the beginning of my trimmed clip.

My question is how can I trim 6.5 seconds off the beginning while also trimming that same amount of time off my timecode as well?

So instead of my trimmed clip (let's say 23.98 fps) starting at 00:59:48:00, it would start at 00:59:54:12 since 6.5 seconds (roughly 156 frames) have been trimmed.

Answer 1

A manual way to do this is via

ffmpeg -ss 6.5 -i "$f" -c:v copy -map 0:0 -timecode 01:23:45:30 -c:a copy -map 0:7  "${f%.*}_ST.mov"

Don't see an automatic way to do this. There is a copyts option but that relates to the video packets, not the ancillary timecode track.