I bought two DVR from a supplier that is unreachable now and another from Fireking. They all claimed to use the Novatek 96650 chipset with F2.0 front camera capable of FHD, full HD, i.e. 1080p.
I tested them, and they all are capable of using 32Gbye memory cards and use similar 2.5mm jack plug to connect to the rear camera. Power is by means of a micro USB connector. The one supplied by Fireking is right angle so it does not interfere with the roof of the car.
The Fireking is the best. It is capable of 1 Megapixel pictures and therefore 800p video which is better than HD at 720p. In the HD video recording mode, the video achieves 700p.