30fps can be helpful for LPR...more frames to choose from
True, but it can also cause problems in certain situations.
I noticed the my LPR camera wouldn't trigger in every instance (I knew this because the overview cam triggered and the LPR camera didn't)
So I noticed while watching it live for an extended period that for my license plate camera (which as you know is zoomed in tight to the road to read plates), I watched it not trigger for a big ole yellow school bus, but then trigger for a tiny 2-door car the next minute that was driving slower and then miss the same car coming back 5 minutes later!
For this plate camera, I was obviously running a fast shutter to capture plates, but also had the FPS at 30 FPS thinking that would be better. When I knocked it down to 10 FPS,
Blue Iris motion started capturing that bus and other vehicles it was missing. I think the motion algorithm for a tight field of view was having difficulty with the faster FPS as there wasn't as much of a difference comparing frame to frame at 30FPS to 10FPS. A vehicle is in and out of my LPR field of view in under 0.5 seconds and I now get trigger alerts and capture every plate at 8FPS (yes I dropped it even further for longer retention of LPR images).