Guide to video settings AND their affect on IVS?

[Fastb]

All,

I recently changed some settings on my IPC-HFW4431M-I2 camera to improve the image and better handle motion. The changes were made based on this thread:
Guide to video settings?

For a couple of days after I made changes, I get many more false alarms from IVS, specifically, "Tripwire". (5 to 6 per day) The last few days have been sunny - unusual for Seattle. Maybe the increase in false alarms is related to sun, ie: IVS "sees" non-existent objects due to sun and moving shadows.

My camera changes:
- Instead of using the single "Normal" profile, I now use two profiles, ie: "Day" and "Night"
- Changed shutter speed from "Auto" to "Manual"
- I set Day shutter speed to 1/250, and the gain range of: 0 to 90
-- 3D NR remains set to "On", with a value of 50
- I set Night shutter speed to 1/100, and gain range of: 20 to 90
-- 3D NR is "On", with value of 50
- I changed I-Frame from 20 to 10
- I changed Bit Rate Type from CBR to VBR
- I changed Quality from 5 to 6



Here are a four pics of IVS tracking "objects". Sometimes the boxes are drawn when the sun isn't making high-contrast areas of shimmering shadows when the breeze gently blows.

Q: What settings might make IVS become hyper-active?

Thanks,
Fastb

 

[nayr]

If you increase shutter speeds then its going to get more noise and it'll think they are objects, try using shutter priority instead of a fixed shutter or go back to auto

 

[Fastb]

nayr,

Thanks for the reply.
As usual, you nailed it. While it's early to say for sure, the problem appears solved.
- no green boxes tracking non-objects.
- It's less sunny right now, I hope that doesn't explain the absence of green boxes

Shutter Priority, with the same 1/250 shutter setting. (pic below)

Thanks again!
Fastb

 

[Fastb]

nayr,

I'd like to understand the Shutter Priority setting, and what it does.

From my photography days, shutter priority meant the camera would use the shutter speed I chose. And to achieve an optimal exposure, the camera would change aperture.

My Dahua camera doesn't have an adjustable aperture (that I know of). So maybe gain is adjusted? And the result is less noise, so IVS doesn't see false "objects". And I still get the 1/250 shutter speed I desire....

I'm just trying to cement this "learning episode" in my head. And the explanation may help other forum members who might find this thread....

Thanks,
Fastb

 

[Fastb]

My "light bulb" lights up a little slowly at times.
I think I answered my question about "Shutter Priority" and how it works.

Short Answer: With "Shutter Priority" selected, "Gain" will be adjusted.

First pic:
In "Manual" mode, a range of gain can be selected.



In 2nd pic:
In "Shutter Priority" mode, the option to choose a range of "Gain" is removed.


I hope this helps some folks!

Fastb