@badmop, What do you mean by bit rate, Is it frame rate of the IP camera or not ?. I am using Hikvision 3MP camera and I have set video recording @1080P on each channel main stream with frame rate of 25.
I bought Mini NVR 2 box from Aliexpress and setup it with external 4TB HDD.
http://s.click.aliexpress.com/e/brORWfpq
The device is showing that videos are recording. But when I try to playback old videos, sometimes player screen becomes blank and some times it load the video, but it doesn't...