Protern Clock, now on Android.
QR Clock: for a camera with no mic input, film the phone screen for a few seconds at the start of each clip and Protern Video (2.3.15 or later) reads the time from the frames.
LTC Audio: plug the phone into the camera's mic input, press Start, and film. The timecode keeps running with the screen off.
Settings in one place: frame rate, audio channel, and the embedded date.