For some reason I can't comment you post but I want to say Thank You! I'm doing something different, I'm overlaying several (30 different) 10 seconds videos over an 1 hour video at a fixed time. I tried all chatgpt models, claude, gemini and cursor. All of them giving me wrong commands. So I decided to study and understand FFMPEG. AI was pointing me to using between to set the time. I got to you post used your command as reference and... its working! This is my full command in case someone with the same problem end up here:

ffmpeg -i 7.mp4 -i 1.mov -i 2.mov -filter_complex "[1]setpts=PTS+0/TB[ts1];[2]setpts=PTS+10/TB[ts2];[0][ts1]overlay=0:0:eof_action=pass[out1];[out1][ts2]overlay=0:0:eof_action=pass[out]" -map "[out]" -t 00:00:30 -y output.mp4