ZoneMinder Forums

Although "Reference Image Blend %" has simple technical interpretation, it is often inconvenient, because it sould be readjusted every time when
frame acquision rate is changed. If pre-alarm and alarm acquision rates differ, it creates another problem. If for example, alarm rate is higer, then this may lead to alarm oscillations - low pre-alarm rate predispose to initiation of alarms, high alarm rate tends to turn alarms off due to faster signal decay (blending goes faster at higher frame rates).

I suggest using blending time Tblend instead of Reference Image Blend %:

Tblend = 100*dt/RIB%,
where:
dt = time period between frames
RIB% = Reference Image Blend %

Tblend is time that it takes to effectively replace previously accumulated reference image (i.e. its relative contribution will be = exp(-1) ~ 27%). Given Tblend it is easy to compute RIB% factor (ideally, this should be done for every frame):

RIB% = 100*dt/Tblend

Hi.

Nice idea. So it basically will auto adjust the blending reference according to frame rate, and prevent loosing parts of the event in the beginning, or splitting to two events due to fast frame rate at the end of the event?

Sorry - I did not realize your post was a question.
The answer is yes.