I've countless hours tuning cameras as do many here. I wont try and write an authoritative guide as I was up too late and only on coffee #2, and frankly Im a hobbyist not a professional but here's some basics.
Its a lot of trial and error as no two scenes are the same and any two different cameras produce different image qualities.
These are just starting points. Many scenes will need hours of tweeking beyond this baseline.
Note: you will almost always need separate Day/Night profiles as the settings can be vastly different.
Daytime is generally easy. Any cheap 2MP+ camera will do reasonably well in daytime with out of the box Auto settings
1- Set bitrate and fps- I like to use 30FPS and max bitrate as shown on the camera specs (usually 6144 or 8192). Also match Iframe to FPS
2-Leave image settings (brightness, sharpness, contrast etc) alone at 50
3- Dont mess with DNR-
50 should be max in any scene otherwise you will induce motion blur. 20-30 will be fine if you have a decent lit scene
4- The 2 most often adjusted settings are backlight and exposure.
- Backlight- WDR is commonly used in a scene with a mix of shadows and bright areas to even out the image. On Dahua cameras I dont recommend anything greater than 20-25
- Backlight BLC- can be used when the background is much brighter than the foreground making your subject appear dark or backlit
- Exposure- generally with good light Auto will do fine. But to allow for overcast or darker areas you may want to use a faster shutter speed to reduce blur. 1/60 or 1/120 is usually enough and many use a range - say 0-2 to allow the camera to compensate for overcast vs sunny changes. (Faster exposure= smaller number. Auto is usually 1/30 max where 1/60 is double as fast. You'll commonly see 1/1000 or faster for fast moving objects and special applications like LPR a night)
Nighttime is where it gets tricky.
1- Decide if you have enough white light and a sensitive enough camera to run color at night.
90% DO NOT HAVE BOTH There's nothing wrong with running good clear crisp B&W with IR vs grainy blurry color when trying to force color at night
2-
Test with a moving person in the video. Still shots that may be beautiful dont tell the story. Anyone can get a good night still shot.
3- Leave image settings (brightness, sharpness, contrast etc) alone at 50. Dont try and use brightness or gamma to lighten up an image at night. You just get a washed out image. You can use incresed GAIN to some degree to brighten the image, but at the expense of more noise.
4- DNR usually needs to be reduced at night to minimize blur. This is the number 1 cause of motion blur. 30-40 max is a good place to start
5- Backlight- - Rarely I'll use a small bit of BLC but WDR has NO affect in B&W so dont use it. In color it introduces blur in low light. HLC can be helpful to reduce the flare caused by bright spotlights, headlights, etc. But will reduce the overall image brightness if you go too far.
6- IR- requires some experimenting as mentioned by
@biggen above, its a matter of adjusting to have enough while not blowing out the image. This is a process of test/tweek rinse/repeat. Reflective objects like soffit or close in landscaping can reflect the IR light and greatly reduce its effective range
7- Exposure- - with B&W/IR I typically run most cameras at 1/60 or so.
In color its a tedious job of experimenting to get enough light while keeping motion blur and noise to a minimum. Again start with 1/60 but i find it takes 1/120 to 1/250 to freeze moving subjects. This means you need a shit ton of white light to run color at night. Again Gain can be helpful but the more Gain the more noise. Its a balancing act.
LPR is another whole topic, there's lots of good information on this in the LPR forum