I removed the SD card from the DVR this morning and viewed the videos on my Windows laptop. I noticed that all the files recorded today were TS files whereas those recorded previously were mp4.
I reinstalled the SD card, powered up the DVR and connected the app with the intention of changing the file format back to mp4. However, when I viewed the settings, many of the others had also changed from what I had set, eg. speed had changed from mph to kph, loop from 10 minutes to 1 min, WiFi from 10 mins to never, etc. It’s as if the app had reset itself and the DVR overnight. Can anyone suggest what might have happened?