Any way to record a few seconds before the trigger?

[bertsirkin]

I have BI to trigger after 1.5 seconds of movement. This helps with moving bushes, etc. But, I sometimes miss the movement that causes the trigger, as the object may move out of the frame by then.

Is there any way to tell BI to record a few seconds before the "trigger" occurs?

 

[anijet]

On the record tab, check the Pre-trigger video buffer box and enter the number of seconds of pre-record you want. Works great.

 

[bertsirkin]

Fantastic - thank you very much!

 

[dryfly]

Fantastic - thank you very much!

Any downside to pre-trigger buffering i.e. increased CPU utilization? Naturally it's going to give you a little larger video file since it's recording more info, right?

 

[bertsirkin]

Well, maybe not so fantastic! I didn't look at CPU utilization until you asked the question, but it went from about 17% to 32%! I changed it back to 0 seconds, and the CPU utilization went back down to 17%.

FWIW, I have 7 cameras and had set the pre-trigger buffering on 3 of them.

P.S., I checked the help file and found this:

Please note that the use of this feature consumes considerable memory and some CPU resources--it should only be used if you have both to spare. In fact, it may be impractical if not impossible to use more than 0.5-1.0 seconds here unless you are also using Direct-to-Disc recording (see below).

I had 3 cameras set to a 2-second buffer - I removed the buffer from all but one camera and set it to a .5 second buffer, and it's only using an extra 3% CPU now, which is acceptable.

 

[yeahman]

yup CPU utilization increase significantly with pre record.
I wonder if this is solved if continuous recording is on?

 

[fenderman]

Well, maybe not so fantastic! I didn't look at CPU utilization until you asked the question, but it went from about 17% to 32%! I changed it back to 0 seconds, and the CPU utilization went back down to 17%.

FWIW, I have 7 cameras and had set the pre-trigger buffering on 3 of them.

P.S., I checked the help file and found this:

Please note that the use of this feature consumes considerable memory and some CPU resources--it should only be used if you have both to spare. In fact, it may be impractical if not impossible to use more than 0.5-1.0 seconds here unless you are also using Direct-to-Disc recording (see below).

I had 3 cameras set to a 2-second buffer - I removed the buffer from all but one camera and set it to a .5 second buffer, and it's only using an extra 3% CPU now, which is acceptable.

yup CPU utilization increase significantly with pre record.
I wonder if this is solved if continuous recording is on?

The difference should not be that dramatic..ensure you are using direct to disk, hardware acceleration and that you have sufficient memory. I have each camera with at least a 3 second pre record buffer.

 

[eandrews19]

Have you tried to set up zones and exclude the bushes? This is how I have resolved false alerts from branches swaying.

 

[Ryan00]

I use a 1.5 pre trigger and it doesn't use any CPU . I put the pre trigger back to 0 and my CPU usage stayed the same .

 

[PancakeBimmer]

It is still not clear if pre-trigger buffer does or does not increase resource usage with continuous recording, but I don't see a reason why it would. Just a matter of moving alert time back by the buffer amount.

@Ryan00 are you using triggered or continuous recording?

 

[Ryan00]

It is still not clear if pre-trigger buffer does or does not increase resource usage with continuous recording, but I don't see a reason why it would. Just a matter of moving alert time back by the buffer amount.

@Ryan00 are you using triggered or continuous recording?

Continuous recording all my cams record 24/7

 

[bitNine]

Yeah, I don't see any difference with the pre-trigger set to 0 or 2, but then 3 of 5 of my cameras are always recording.

 

[robertsig]

Does pre-triggering recording occur in memory or disk? So is the constant buffer of extra "recording" always writing to disk or RAM? If RAM, that's a pretty cool feature!