223 lines
10 KiB
Markdown
223 lines
10 KiB
Markdown
---
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title: "Construction site surveillance"
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date: 2025-04-01T14:26:00+02:00
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---
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I am building a house, for which I decided I need a surveilance cameras. I have
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never set up a security camera, so have zero knowledge before starting. Here
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are the prelminary requirements *before I started*:
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- 24/7 on-demand live view, plus some recording: 7 days 24/7, plus some time
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for when and around "motion" is detected.
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- Nothing that has a subscription fee. ring.com is pretty good for short-term
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plug&play, but I cannot brace myself for a yearly payment, especially that I
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have (and can afford to maintain and upgrade) storage, network and compute.
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Network subscription is a fine service to pay for, SaaS is not.
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- Use off-the-shelf hardware, so I am only minimally required to maintain the
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setup (so no DYI webcams or routers).
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This post highlights some things I wish I knew before buying & setting it all
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up.
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# The Components
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Since the building site is "remote" (there is no existing infrastructure
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besides electricity), networking needs to be self-contained. This is the setup:
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```
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o-
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/\
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Camera
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LTE/5G Router
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<public internet>
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NVR
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```
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* Camera is the single most important component. Easy to understand what it is
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and why it matters.
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* One can easily "live view" directly in the camera stream. Cameras can usually
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record video into a builtin SD card. However, that's not very useful if it
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gets vandalized or stolen, so better continuously push that video somewhere
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safe.
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* *NVR* is a Network Video Recorder. Besides the camera, this is the *second
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most important component*. NVR captures a video stream from the camera,
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(optionally) detects people and vehicles, and records everything. Since NVR
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is the main "interface" to the surveillance system, not the camera, it is
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important NVR has a good UX. You don't care about the camera UX after it's
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set up.
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# Video codecs
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There are two codec choices, mostly:
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- *H.264* is a royalty-free video codec from 2003. According to a [reference I
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found in Wikipedia][14], it was used by 91% of video industry developers as
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of September 2019. Every screen-equipped device that I tried can play it.
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- *H.265* (a.k.a. _HEVC_) is a royalty- and patent-ridden codec which offers
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25-50% [better compression ratios][15]. In my experience, the compression
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ratio was over 50%. It is amazing for transfer, un-playable on everything
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I've tried except Google Chrome browser on Android[^1].
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- *AV1* seems to be anecdotally on-par with H.265 and is not patent-ridden.
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Camera cannot stream it, but lack of patent problems implies, it should be
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good for recordings. However:
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- I was not able to (easily) setup go2rtc with AV1.
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- The 5-minute experiments yielded similar bitrates for similar quality. In
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the end, I decided it's not worth the hassle until go2rtc offers a packaged
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configuration for it.
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- *H.264+*, *H.264B*, *H.264H* and similar. They are "close" derivatives of
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H.264. Software support is hit-or-miss, so I mostly ignore those.
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# Picking the camera
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[A friend of a friend](https://jpg.lt/), who has been setting up security
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cameras for the last 15 years, recommended Dahua. I picked a model and went
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into it.
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There are a few variables you may want to check:
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- Pan, Tilt, Zoom (*PTZ*). Some cameras can change the viewing position
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remotely. I picked one with PTZ, but more out of curiosity than necessity.
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Turns out, ONVIF (the "open" protocol to control PTZ cameras) is very poorly
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supported, or not at all, with the NVRs I've tried.
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- Resolution versus visibility in low light. [ipcamtalk.com][2] has decent
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recommendations, start there.
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- Do your research in the [website][2], there are some great tips. I wish I had
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known about it, or at least read the Dahua part, before purchasing mine.
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Note that most cameras are designed and manufactured in China. Which,
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unsurprisingly, have [bad reputation in the Chinese-controlled areas][1].
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# Network Video Recorder
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Once you've settled on the camera (and the number of cameras), there are mostly
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two options for an NVR:
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- A dedicated set-top-box-sized device from the camera manufacturer. These are
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completely hands-off in terms of maintenance. A hard drive is usually
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purchased separately, depending on how much should be recorded. The UX
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experience is "it is what it is". I.e. camera manufacturers may or may not be
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the best NVR UX designers, especially when it comes to viewing the recordings
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or live stream remotely. However, they will for sure create the best Camera ⇔
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NVR integration.
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- Open source NVRs, which you can install to your existing home server. I
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considered [frigate][3], [Moonfire NVR][4] and [ZoneMinder][5]. Since I use a
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[home server]({{< ref "log/2023/nixos-subjective" >}}), I am self-hosting my
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NVR.
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## Moonfire NVR
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*Moonfire NVR* seems like the simplest of the bunch: low hardware requirements
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(raspberry pi 2!), minimal number of features. Cons: does not have object
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detection, not even "in theory". I have relatively powerful hardware in the
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closet and want object detection for it.
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Moonfire NVR's interface is ncurses-based, similar to how Linux kernel is
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configured. In opinion, for end-user product, one either offers file-based
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configuration, or web-based configuration directly in the browser. Many
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projects do both (e.g. home-assistant, frigate). This is the first ncurses-based
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configuration for a consumer product. Which makes me wonder what their audience
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is.
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{{<img src="_/2025/construction-site-surveillance/moonfire-config.png"
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alt="Moonfire-NVR ncurses-based configuration dialog"
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hint="graph"
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>}}
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Once configured, the recordings are printed as a timestamped list. Which is
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good if you know the time upfront, but is not great for discovery.
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{{<img src="_/2025/construction-site-surveillance/moonfire-nvr.png"
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alt="Moonfire-NVR web dialog with a list of recordings"
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hint="graph"
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>}}
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## Setting up Frigate
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*Frigate* seems to be what the kids use these days. Documentation is extensive,
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though sometimes not very accurate, but [their forums][13] compensate for it.
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It took a few evenings to get it to work, and it works.
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A few tips before you get started:
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- for object detection you will need hardware support. Look at [recommended
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hardware][6]. I went with Google Coral, but I've heard good things about
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OpenVINO too.
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- start with go2rtc from the get-go. I had to re-configure all the Frigate
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streams, which was way more annoying than it's worth if you start with
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go2rtc. Saved a lot of bandwidth, too. More on that later.
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## Connecting the camera
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I bought [Teltonika Rutx11][8] 4G router/wifi modem that will fit in the
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[camera junction box][9]. Antennas will be outside:
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- [External 4G antenna from Mikrotik][10].
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- [Wi-fi dual-band magnetic sma antenna from Teltonika][11].
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I purchased an unlimited 4G plan from an ISP that has good connectivity in the
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area. Then connected the Rutx11 via tailscale/[headscale][12]. Using tailscale
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I can connect to the camera directly from both my NVR and all personal devices,
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a yet another tailscale+headscale recommendation.
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I disabled outgoing connections from the camera on the router. As a nice
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side-effect, I have a _really nice_ WiFi hotspot in the construction site.
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## Bandwidth and codec considerations
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Two camera streams (`2688x752` and `1920x1080`), encoded in h.265 consume
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around 2Mb/s 24/7. Both streams are transcoded to h.264 via go2rtc and then
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sent over to Frigate and live view. Then recorded as H.264. Recordings for both
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cameras take ~21-24GiB/day.
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Every 5 minutes a separate process captures a full-resolution picture of both
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cameras: `5376x1520` and `2560x1440`. I have a bunch of timelapses already! If
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we meet in person, I will happily show.
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{{<img src="_/2025/construction-site-surveillance/grafana-traffic.png"
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alt="Grafana dashboard showing ~2Mb/s downlink and ~100Kb/s uplink over tailscale0 interface"
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hint="graph"
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>}}
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Using exactly the same parameters (resolution, fps), but with h.264, the
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bandwidth grows to 11 Mb/s. Which may not sound like a lot with today's fiber
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everywhere, but is considerable on a 4G connection.
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Since the home server has a graphics card, it can use hardware acceleration for
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video encoding and decoding. Thanks to proliferation of online video platforms,
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those decoders and encoders are available on even the cheapest hardware.
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It takes ~5-10% of a single CPU core to transcode a stream, depending on the
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resolution. In my case, I am transcoding 4 streams (2 cameras, "low" and "high"
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res each), so in total transcoding uses about half of a core with minimal
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bandwidth.
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Once the house is complete and I move NVR to the same physical network, I will
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change the encoding to h.264, stop transcoding and use more video bandwidth
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locally.
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# Final notes
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With the current open-source NVR ecosystem and the price of consumer-grade
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surveilance cameras (low hundreds of €), I highly recommend setting one up if
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you are building something. It takes a few weeks to learn all the dusty
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corners, but, in my opinion, in the end it's worth it.
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[1]: https://uhrp.org/statement/hikvision-and-dahua-facilitating-genocidal-crimes-in-east-turkistan/
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[2]: https://web.archive.org/web/20250221205936/https://ipcamtalk.com/wiki/ip-cam-talk-cliff-notes/
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[3]: https://frigate.video
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[4]: https://github.com/scottlamb/moonfire-nvr
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[5]: https://zoneminder.com/
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[6]: https://docs.frigate.video/frigate/hardware
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[8]: https://teltonika-networks.com/products/routers/rutx11
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[9]: https://www.dahuasecurity.com/products/All-Products/Accessories/Camera-Accessories/Camera-Mounts/Junction-Boxes/PFA126
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[10]: https://mikrotik.com/product/mant_lte_5o
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[11]: https://teltonika-networks.com/products/accessories/antenna-options/wi-fi-dual-band-magnetic-sma-antenna
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[12]: https://headscale.net/stable/
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[13]: https://github.com/blakeblackshear/frigate/discussions
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[14]: https://go.bitmovin.com/hubfs/Bitmovin-Video-Developer-Report-2018.pdf
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[15]: https://en.wikipedia.org/wiki/High_Efficiency_Video_Coding
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[^1]: or vlc. Thanks to the French who make a point about not caring about royalties
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