Need help with nodect understanding

[lk777]

Hi all,

I am new to ZM and the nodect confuses me a lot.

My scenario (2 streams from one camera): Lowres - modect,Hires - nodect. Hires is linked to Lowres

If I understand it correctly, all analysis and motion detection should be done on the Lowres stream (modect): Analysis Enabled, JPEGs, Video - disabled (my settings). So it just asks/triggers a Hires monitor to record an event.

If it is so, may I assume that the hires monitor (nodect) doesn't need to analyze anything just does a simple recording?

Following my logic, I have unchecked "Analysis Enabled" (though it says "...When not enabled no motion detection or linked monitor checking will be performed and no events will be created. ..") and JPEGS disabled (for the test purposes).
What I see is events are created on hires monitor with Alarm frames, Avg. Score, Max score, Frames. So it definitely analyses something.

Does Nodect need any zones to work?


Is this a result of some hidden foolproof algorithm?

What are correct settings for this scenario?

[tsp84]

Can I ask why you would have it setup that way? or is this just for testing and you are planning on mocord for the low res after? OR is this a processing limited platform?

modect on the hi res would work exactly the same as you have it setup now (minus any difference in buffer/alarm frame count).

To your question, are you asking if the hi res monitor is analyzing things even though you have turned analysis off? or?

[lk777]

The analysis of the high resolution stream is quite CPU/Memory intensive process. If I understand it correctly, the purpose of the linked monitors (in this case, 1 camera - two streams) is to analyze the low resolution stream to make it computationally less intensive and to trigger the high resolution recording.
So my questions are:

Can I disable analysis in the hires monitor and just to record video (passthrough)? Though I see that in hires events there is information which can be obtained by some analysis, I believe.
Does the hires require any zones?

So far I was struggling to make linking work stable.

[dougmccrary]

"Does the hires require any zones?"
The default zone is the entire field of view. In your use case, I don't think you need a zone, if you're thinking of deleting it.

[lk777]

I do not see any column AnalysisEnabled in the database zm / table "Monitors", so this probably explains why unchecking "Analysis Enabled" doesn't disable analysis on my hires monitor. But I might be wrong.

Regarding zones on HiRes (nodect) monitor: it seems that zones are not necessary for my setup and the HiRes analyzes the whole stream (triggered by the LowRes monitor (modect)). It creates events with much more Alarm frames than LowRes monitor which has zones (3 active zones - 3 narrow rectangles).

Is this by design?

I would prefer and expected it to have nodect to record triggered events (with no analysis). Modect on HiRes monitor with zones would do better job than this modect-nodect setup.

[Pedulla]

I use the linked monitors for all of my family installs, however I've always used "Modect" on the lowres stream, then "Nodect" on the hires stream. I don't know how well it works with "Mocord" on the lowres stream.

If you have differing frame rates between the two streams, you will likely never have exactly the same event clip on both streams, but you can get it close by using a number of pre & post event buffers on each stream that will correspond to the same amount of actual time.

In Nodect mode, the hires stream does not have analysis performed on it so the analysis area is ignored, only triggers from the linked monitor will kick off an event record, that's why the buffer thing above is important to get right. In this setup the analysis is only done on the lowres stream and is pretty light duty. You can lighten the load even more by slowing the frame rate down to 2-4fps on the lowres stream. You're looking for changes; the longer the time between frames the easier to detect changes.

I've left the Analysis Enabled flag on assuming if off it will disable the hires streams links to the lowres stream, because a trigger from lowres is something that is detected by the analysis process(at least I thought so...); but you're saying you get hires events anyway... hmmm I'll have to try that.

Never the less...
After using this setup since 1.26, I've gone to Modect on the lowres stream @4fps and Mocord on the hires stream with no analysis zone (Mocord, does analysis, so just get in and get out quick). In this way I can blast through low res events, but my continuous records have event markers in them for more detailed review.

Also use camera passthrough whenever possible for lowest cpu impact.

Hope this helped.

PS. Also check out using 32bit color instead of 24 in your monitor settings. It's not intuitive, but lowers the cpu usage.

[ZMfan]

Also interested in these settings.

Now OPT_TRIGGERS enabled.
In Moniror Triggers are not available.
If select "nodect", nothing else appears.
what other settings do I need to make on the ZM side?

For "nodect" need Analysis Enabled?

my cameras with motion detector function. But I do not know which of the settings is better to apply in the event server. Screenshots are attached