HOME VIDEO CAMERA SPECS
The minimum would be 1080p, 3 megapixel cameras,
IR (Infrared), able to record to the DVR @ 30 frames per second.
Keep in mind it's important that the DVR be able to records at a minimum of 30 frames per second (fps) at 1080p resolution.
You have to really read the specs on consumer packages because sometimes they will tout "1080p" but they only display at 30fps on your screen when viewing live video, but record to the DVR at a lower frame rate (i.e. 20fps, 15fps, etc.). This makes the video choppy when you play it back and blurry when you freeze it.
Some consumer systems do greater than 1080p such as 4 megapixel and then higher at 4K. These are very high resolution when viewing live video, but sometimes these systems have trouble recording to the DVR at the required frame rate (i.e. they only do 10 fps, 15 fps, etc.).
For reference, live TV is usually 30 fps. Most importantly, the higher the frame rate recorded, the clearer the video will be when you freeze it for identification.
SAMPLE SYSTEM - COSTCO
I hope this helps.
Sergeant, North NPC
Riverside Police Department