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ONVIF & Pre Event Image Count ???

Posted: Wed Feb 21, 2024 4:58 pm
by IgorA100
I still can't figure out if the Pre Event Image Count buffer value is used when using ONVIF detection?
Logically, it should be used with "Decoding = Always"
In practice, it seems that it is not used.

Re: ONVIF & Pre Event Image Count ???

Posted: Fri Feb 23, 2024 2:12 pm
by iconnor
It should be. The packet queue should maintain a buffer of that size + keyframe. SOmetimes it can't and there will be a log entry about it.

Re: ONVIF & Pre Event Image Count ???

Posted: Sat Feb 24, 2024 3:40 pm
by IgorA100
Yes, Pre Event Image Count & Post Event Image Count work when using ONVIF detection if specified:
Decoding = Keyframes + Ondemand and Decoding = Always. I haven't checked for other "Decoding" values.
BUT! the above buffers are not used correctly.
I use a short-term event ~1-2 sec.
For example, the camera has 20FPS, if I specify

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Pre Event Image Count=20
, then the event is not recorded! If I specify

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Pre Event Image Count=60
, the event is recorded, but there are only 40-50 frames before the event. At the same time, the location of the event is not correctly marked on the time strip; as a rule, the marked event is shifted forward in time, although in reality it happened earlier.