I am a DVR owner a119s.
The ability to change the video bitrate in the recording settings is a sign of a good, high-quality DVR.
Include in the menu option the ability to change the bitrate of 20 Mbit / s, 30 Mbit / s and 40 Mbit / s.
With the current bitrate settings (20 Mbit / s), car numbers are read only from a distance of 5-10 meters.
This will allow the owner of the DVR to find a compromise between video quality and video recording time.