ZoneMinder Forums

Ladies and Gentlemen;

I've been evaluating ZM 1.18.1 for a week now - and I have to say that it's a really good system.

Something that has me stumped though - I want to be able to capture "alerts" at 5 frames a second, but when nothing is going on - I only want to capture 0.5 frames a second. When I say capture - I mean saving the frame to disk.

I've tried playing around with the "Maximum FPS" option - however, since ZM has been capturing at 1 frame every two seconds - I find that I get the first 5-10 seconds at 0.5 FPS, then capture at about 5 FPS until the movement is gone.

Perhaps I'm not setting it up right - but figured I'd ask.

For those who want to know - we're trying to run 6 AXIS 2100 cameras with ZM on RedHat Advanced Workstation 3.0. Currently, we're looking at around 10mb per 5 minutes.... and since we want to keep the footage for 30 days - we're hitting a rather LARGE disk space figure. Anything we can do to keep the disk space to a managable level would be perfect.

Does anyone have any disk saving techniques? Thank you!

--Logically Rogue

Hi Benjamin,

I'm a bit confused about these two statements which seem to conflict,

<i>I want to be able to capture "alerts" at 5 frames a second, but when nothing is going on - I only want to capture 0.5 frames a second</i>

and

<i>I find that I get the first 5-10 seconds at 0.5 FPS, then capture at about 5 FPS until the movement is gone</i>

Is the second statement not define what you are are after in the first? I'm not quite sure what isn't really working. Perhaps you can elaborate.

As for a disk space figure. Are you running in 'Mocord' so capturing the whole time? If not then obviously your disk space usage will be variable. The most important factors affecting storage are the JPEG quality and the maximum FPS which you have discovered. What sort of capture rate are you getting from your cameras at full throttle?

One thing that might be useful a little way down the line is MPEG based storage. I'm finishing up a version which has on the fly encoding for live and event viewing and some time after that I'll be trying to create a method by which an event can be stored and accessed in MPEG only. This will obviously reduce storage considerably. You may well be able to hand craft something like this now.

Cheers,

Phil,

My apologies - I believe the word "brain dead" sums up my mental state this morning...

Let me rephrase.

Ideally - I want to be able to capture high frame rates when there is movement, but extremely low frame rates (1 frame every 2 seconds) when nothing is happening.

Previously, I was using Frame Skip = 0, limiting Maximum FPS to 0.5. Using those settings, I'd have 1 frame per second when there was no movement, still have 1 frame per second for about 5-10 seconds into the "alert", then ZM would go to 5 or 10 FPS (whatever Axis 2100's do) for the remainder of the event.

I was limiting my frame rate until ZM detected movement, when it would kick up the frame rate. I'm guessing that I was a victim of my own stupidity.

After I posted - I played with some settings, and the best I have come up with is to thi:
Mode: Mocord
Frame Skip: 10
Pre and Post Event Image Buffer: 50
Maximum FPS: 5
All others default.

This gave me the low frame rate when nothing happens, yet 5 FPS when ZM detected movement.

To answer Phil's questions:
I think I can get 5-10 FPS from the Axis 2100 cameras at "Low" Compression.
We just calculated this for disk space:
- 4 Cameras using the above settings across 15 minutes = 70 megabytes
- Those 4 cameras across 1 hour = 280 megabytes
- Across 1 day = 6.7 gigabytes
- Across 30 days = 201.6 gigabytes

I don't like those numbers - makes me wish I had a terabyte array for this project. Now, granted, I'm basing my calculations on a 15 minute sample when the building is pretty much dead (it's Spring Break here). I'll have to just watch for a while and see what happens...

--Logically Rogue

Hi,

That's a bit clearer now ;) What image size are you using?

Phil,