Carrying straight on from my last post, this is the second part of my look at Surveillance Station on a Synology NAS.
I’ll start off with motion detection. As I explained in the first part, I’m recording continuously but I still want motion events to be flagged in the timeline. Surveillance Station has two options for the source of motion detection – either via the camera, if your camera can do motion detection, or in the Surveillance Station software itself.
There are advantages to doing the motion detection on camera. Firstly it spreads the load, especially if you have several cameras. If each camera is doing the motion detection processing you’re making better use of the resources and taking load off of the NAS.
Secondly, if your camera has passive infrared (PIR) motion detection you may get more reliable results than you would by processing the image.
That said, I’m using Surveillance Station to handle motion detection. My camera can do it, but setting it up requires browser plugins that aren’t now widely supported. Since I only have one camera at the moment the load isn’t too great and it keeps all of the configuration in one place. I’m just using the camera as a raw feed.
The motion options when using Surveillance Station are quite basic, especially compared with Zoneminder. You can select the detection area and set values for sensitivity and threshold. The documentation doesn’t make the difference between sensitivity and threshold particularly clear:
So sensitivity triggers more easily on high values and threshold on lower values, but it’s still not clear how a “difference between a series of frames” differs from “larger movements”. Presumably larger movements will always lead to a larger difference between frames?
As is always the case with motion detection parameters, experimentation is needed. You’ll need to tweak the settings until you get the right balance between missing events and false positives.
Despite the limited options for tweaking the motion detection, I’ve found I can get Surveillance Station to pick up events almost as accurately as Zoneminder. You can get a bit bogged down with the parameters in Zoneminder – there are almost too many options to play with. The main problem, as with any motion detection that works by comparing images, is that changes in light can lead to false positives. Shadows can be a real problem – I have a tree just out of shot and on a windy day when the sun’s in and out of the clouds I can end up with a constant stream of false positives.
When motion is detected, Surveillance Station ends the current recording and starts a new file. Although there’s an option to set pre- and post- recording times for the regular recordings those options don’t apply to motion detection recordings. It would be really useful to have that feature, especially if your motion detection area is less than 100% of the frame – a person entering the area might not trigger motion immediately so it would be good to have a little context either side of the detected event.
It’s not a huge problem if you’re recording continuously – you can just check the end of the previous recording or start of the next one – but is something to bear in mind if you only want to record motion events. Zoneminder can handle that with its buffer options, and is probably a better choice if you don’t want to record continuously.
Assuming you manage to get the motion events to a manageable level, you’ll want to be notified when they occur. There are three options – email, SMS and push. The email option lets you use any email provider that supports SMTP. You can customise the subject, attach a snapshot of the event and limit the number of events within a given time interval.
The SMS option lets you use an external SMS provider, by default clickatell, to send the notifications as SMS messages. Again, this lets you throttle the notifications.
Finally, the push service allows you to use Synology’s email server to send to a verified email address or push direct to the DS Cam mobile app.
It would be good to be able to use something like Pushover instead, or call a generic web API. There may be a workaround – the SMS service seems to work with any provider that supplies an API endpoint that accepts certain parameters. In theory it would be possible to create an endpoint in Home Assistant to receive the messages and trigger notifications.
So far I’ve been comparing Surveillance Station with Zoneminder, as that’s what I was using before I got the NAS. Zoneminder isn’t the only option though. I had a quick look at other options, both open source and commercial, that run on Linux.
- MotionEyeOS is a complete distribution designed to run on a Raspberry Pi. It presents a user interface to the motion backend and, as the name suggests, is designed to do motion detection rather than continuous recording.
- Kerberos.io is another open source option. It has a more modern look and feel than Zoneminder and, like MotionEyeOS, can be installed as a Raspberry Pi image. Again, though, it’s designed to detect motion and does not have a continuous recording option.
- Xeoma is a commercial alternative, and does offer continuous recording. The cost depends on the number of cameras and the type of licence – Xeoma offer Lite, Standard and Pro tiers. It’s not expensive, and although it’s an annual licence you only need to renew to get updates and ongoing support. While it seems to have a wealth of options it appears to be fairly complex to set up. I don’t mind figuring out complex installations of open source software – it goes with the territory – but if I’m using commercial software I figure one of the things I’m paying for is the ease of use. It does look like an interesting option that might be worth considering if you want to run your CCTV software on an existing Linux machine rather than use a separate device.
It’s worth mentioning in passing that there are other options that run on Windows. I didn’t look into them because I don’t have a Windows machine running 24×7, but they include the open source iSpy and the commercial Blue Iris.
Back to Surveillance Station and to summarise my thoughts it’s good but not great. It does everything you’d expect but there are a few user interface niggles, the motion detection could be better and there could be more options for notifications.
Is it worth it as a standalone recorder? Probably only if you already have disks available to use in a NAS. If you’re going to make use of the other features of your NAS then it’s a much more attractive proposition. I’d definitely recommend it as part of the overall package, just make sure you have other reasons for getting a Synology NAS in the first place.in Home Automation