Event creation control

[SyRenity]

Hi.

This a thread dedicated to monitor parameters which control the events creation. I wanted to continue it from this thread http://www.zoneminder.com/forums/viewtopic.php?t=5378, in order to discuss tips and tricks of how the recorded events can be controlled.

To remind the matter in my case, I had many small events, ranging around 0.5~1 secs, which eventually caused me to hit the 32,000 ext3 limit. By increasing the post event image buffer (located in monitor properties) 2x for each camera, I managed to reduce the number of events to a half of the original, thus I resolved the 32K limit.

Are there any guidelines, regarding the usage of these parameters, which can allow to set an optimal configuration? If not, I think it would be great if we could share them to ensure each can pick what suits him the best.

[zoneminder]

To quote myself on the other thread...

The other thing you can try is to reduce the reference image blend %ge. This controls how fast an image is merged into the reference image. If this is large then a new image is merged into the reference very quickly, so someone standing in front of the camera becomes part of the background. If this is small then the reference image is much more static and so someone in the field of view will stand out for a lot longer causing an event to persist.

I think the default is 10%, try 5% or possibly even less.

This parameter I think is one of the most underused methods of tuning ZM. Setting it to a lower value will cause an event to persist just as setting the post event buffer size will but it will cause those additional frames to actually be alarm frames so whatever has caused the event will continue to stand out, whereas just changing the buffer will pad the event with otherwise normal frames. If you have a camera pointing at a permanently lit scene such as a corridor then you can probably set this to a really low value to almost freeze the background reference image. However if your camera is pointing at a scene where lights go on and off or the sun goes behind clouds etc then if it is too low you will find you get long events as the reference image gradually tries to incorporate the wholescale changes to the scene.

Phil