So there are a few methods out there for testing a camera's latency from a certain output, but here I will go over how I do it. The below articles are there for help with streaming settings or even getting the camera onto the network. 

 -How to get the camera on the network -

Streaming Setup Guide -

1. First off, you would want to do this testing using all the cabling and the same software you would want to use while streaming. We see a lot of people using OBS, Vmix, Or Wirecast but in this article, I will be using OBS. 

2. Once you have everything hooked up with the cables and software you would use for your production, pull up the camera feed using the output you wish to test latency on. For this article, I will be using the RTSP feed of a 20x SDI camera, and pulling it into OBS. 

3. So, I have my RTSP feed into OBS and am pulling in an audio feed from my computer as well. I want to know how much to delay the audio by to match the delay in the video. Since I am pulling the RTSP feed over the network, I know its going to be a good bit.  

4. So now you need to position your camera to view your computer screen, this may be a bit awkward, but you have to do it. Use the zoom and PTZ functionality to zoom in on your computer screen with OBS running to see the feed. You may need to move your camera around, but just make sure to keep using the cables you plan to use for the permanent install. 

5. Pull up A Millisecond counter on Youtube, and this is what you will position your camera to view. The one I used for this article is linked below.

6. You should have something similar to the screenshot below. This is the millisecond counter and OBS with the camera feed on the same screen, and that camera feed is pointing at the monitor. You just need to be able to see the ms counter in the (2) places.  

7.  Now, you would hit play on the ms counter in Youtube, and then stand back a bit and snap a picture with your cell phone.  You just need to be able to read both sets of numbers. 

8. Now just subtract the number in your software, in this case, OBS, from the number showing on the counter. In this case, I have 942 - 302 which equals 640 milliseconds of latency. So now I know exactly how much latency that feed has. If you go into OBS, go to the advanced audio properties, and in that window is a "sync offset" for each audio source. You should find your active source, and delay it by 640 milliseconds. This should sync up your video and audio. 

9. If you are seeing varying latency it could be a sign of a greater issue with the network or the computer pulling the feeds in.  Check out this article for more information.