You are almost certainly going to want to use something like ZoneMinder, iSpy, or Shinobi to manage your cameras. openHAB pretty much lets you show the video feeds on your sitemap. That’s about it.
There are some tutorials for other things that can be done with IP cameras like show the feed in PIP on a TV, but most of the heavy lifting takes place outside of OH. OH is a home automation system, not a CCTV system and there is very little overlap between the two requirements.
Not everyone requires going all the way with a CCTV software running on a server. When choosing your camera, select one from a brand that this binding has better support for, then you have the option to use these cameras with or without CCTV software or to slowly build the system as time and budget permits.
Correct. Intel for its QuickSync. I actually purchased a GTX 1080 to see how much more headroom Nvidia CUDA will give me. My CPU% was roughly the same with all the tweaks I could think off. The GPU was returned to Amazon
if your record or base unit for your CCTV exposes rtsp ports for each camera, or all your cameras are ip cameras you could look at something like motioneye. That’s what i use. MotioneyeOS on a raspberry pi or two (depending on if i hijack one or not) then i have motioneye running on a vm to do the heavier lifting (motion dectection, recording, ect.) Motioneye also exposes all the individual cameras on a different RTSP port, so you could load specific cameras in to openhab’s dashboard or hit the url for a snapshot.
At one time I had a motiondetection script running on motioneye, that tripped a virtual switch in openhab for motion detected. Turned on lights, and openhab would create an email with a snapshot of the camera and sent it to me, as well as sending messages to any and all XBMC/KODI boxes on my network.