Over the last five years, we have used a number of ePMP1000s feeding non-PTZ cctv cameras back to a network video recorder with very good results. But one installation is presenting a new challenge. Controlling the IP based PTZ cameras is very sluggish.
It involves a PTZ camera with a ePMP1000 at a non line of sight location being linked through two more ePMP1000s to a fourth ePMP1000 as an AP. The location with the two ePMP1000s is line of sight to the NLOS camera and the AP. This relay sight also has a PTZ cctv camera. The links are used only for video, no other data is being used.
The video from the two cameras is perfect and very low latency. However trying to control either PTZ camera is almost impossible due to very high delay. The IP cameras are HD and bandwidth at the AP from both cameras is around 15 meg. Testing each link shows ratings of 95-100%.
I've tried various parameters in the ePMP1000s without improvement. Is there a set of "recommended cctv settings or maybe a white paper discussing proper software configurations for PTZ cctv installations?"
What is the latency from your computer through all those hops to the camera? If you're plugged directly into the camera, or on the same switch port as the camera, is PTZ more responsive?
I set up just one link on one camera in my shop and it worked great. Just like it was hardwired.
It seems that by adding the second camera the downstream data is saturating the link and not allowing the upstream PTZ commands to reach the camera without high latency.
I did not set up the two camera link in my shop, only on-site.
As currently installed, I am not able to control the PTZ of either the first camera or the second camera very well. I have not tried disabling the furtherest camera to see if that makes the closer camera PTZ responsive. I just thought it strange that the upstream PTZ data is tiny compared to the video load coming back toward the AP.
If you're using flexible for your downlink/uplink ratio, you might want to try using a fixed ratio, like 50/50 or 75/25 split to ensure that your links have enough bandwidth allocated in the opposite direction for your computer to control your cameras. You may also want to use either ePTP mode or switch to 2.5ms frames in order to reduce latency and thus possibly make sending PTZ commands to the radios just that much quicker. A few more things to try would be to modify the encoding/compression method on the cameras to transfer less data and thus help keep from saturating the radios. You also should investigate the overall quality of your links. Have you done link evals on each one? What's the latency? Are you running into interference or poor link conditions that would cause for reduced bandwidth and poor latency/jitty? Are you sure you've engineered the links to be more than adequate for your camera's bandwidth demands?
Thanks for your input. I will try your suggestions when I get back on-site.