[mythtv-users] Joining MP4s

[James]

I recorded a movie that I want to save. Due to the whims of the Australian Open my 20 min post record failed by 2 minutes. Playing Amazon Prime in a VM I screen captured the last 2 min of the movie..

I now have my movie-2min with commercials cut stored as a 'Movie' It plays perfectly.
I have the last 2 minues as a clip. It too plays perfectly.

Each is 720x576 16:9 24.99 Hz. Both are h264 in a mp4 container. The OTA recordings are interlaced.

How on earth can I append the end.mp4?

I tried shotcut which re-rendered giving perfect video but lip sync of 500ms variable, with the end clip in sync
I tried mythffmpeg which muddled everything ie repeated sections general chaos

mythffmpeg -f concat -safe 0 -i /store/TScut_work/file -c copy /store/Movies/Myth-V/Thur\ Vow.mp4

Any experts with handbrake et al

Of interest *some* OTA 720 and 1080 videos maintain lip sync, some do not. I've not looked why I occasionally shotcut a snip to put the MOV atom at the front of the file for downloads.

EG http://tigger.ws/downloads/qna.mp4

James