video/motion detector with C4

[fvolk]

Now that the C4 is already sometime on the market, I'm considering to revisit a project idea of mine,
making a surveillance installation for my parent's garden.

C4+USB attached webcam (UVC video?)
Monitoring the garden 24/7.
Should ignore random noisy pixels and slow changes due to day/night cycle.

Should trigger when someone opens the front gate, goes around the house (cams to be placed in house's windows), and to the garden/shed at the side and does... "stuff" there.
Record interesting clips with date/time stamped to NAS (either via Wifi or cable, don't know yet).

Q: Anyone ever done something like this?
Is it possible to take advantage of C4 hardware encoder for this or webcam (which one is good?) needs to provide an already encoded stream?
How many cams one C4 can drive?
Any software recommendations?
Maybe add an VU7C display to it?
Or need something stronger, like an H3?
...

Suggestions welcome if this is feasible.... :-)

[mctom]

There was a topic of someone's home CC system, but can't find it ATM. I believe there is a suite for managing this, together with web interface and whatnot.
I hope that rain droplets on the window won't count as significant changes in the picture.

One loose idea: The very crude method for detecting changes in compressed video streams is to monitor its density (bits/s). Compressed video with any changes will obviously be larger, and the difference is often significant.

[rooted]

@mad_ady should know what you're referring to, I do as well but can't remember what it's called

[mad_ady]

Last I looked at this there were two projects handling the cctv needs: zoneminder and shinobi. Zoneminder is older, but may have a larger userbase. Shinobi is shinier.
I played with both a little, but on intel.
Zoneminder allows you to define regions in the image where to do motion detection, but yes, you're going to get lots of alerts when the wind blows the trees around.

Note that both solutions support ip, usb cameras, and zoneminder can also read snapshots from a file. Both solutions use ffmpeg to get snapshots from the video stream and do motion analysis on the snapshots. I don't know if any project uses opencv to add object recognition - it might be useful to filter alerts. I think both have mobile clients and can be integrated in HomeAssistant.

As far as I know, zoneminder records clips as a series of jpg files. I don't like it, but it might make sense for security footage, where you want to see details fromonw frame to the next.

As far as I know they don't use vdec support, except when supported by ffmpeg. User @pat2 runs zoneminder with a bunch of cameras on xu4.

[fvolk]

Thank you for the suggestions so far.

No one has an idea whether hardware encoders of C4 are an advantage and used?
Or it does not really matter what hardware is used and practically its more of a software problem?

[mad_ady]

As far as I know hardware encoders are not used, nor represent an advantage. The software reads still photos from the camera and writes jpeg images to disk. From c2 days I remember that the hardware jpeg encoder was slower than software turbo jpeg. It also has the disadvantage of needing to be used by only a process at a time, so it's a headache to use with multiple streams and could create a bottleneck.