Add timecode information to file
@Gyan gives the answer in comments:


  MP4s and MOVs store only the TC of the first frame, as a literal frame count, along with the framerate. The consuming app converts that frame count back to a TC string using the framerate. For drop-frame TC, ffmpeg only supports 30 and 60 fps. I'll add 24/48 when I have time and a SMPTE reference that I can consult. For non-drop TC, any fps is fine. Add -timecode HH:MM:SS:FF to your cmd. Use ; for the final separator if TC is drop frame.