What you are looking at
785 cameras, and 776 of them are the reason the app
exists. A camera on this map is published in one of two ways. The
green ones are live video in a format a browser speaks, and they play here
directly. The amber ones — all but 9 of the cameras here,
including every one of Arlington County's 310 — are RTSP
cameras. RTSP is the
format security cameras and video walls actually use, and no browser can
open it: not Chrome, not Safari, not Firefox, and no web page can add the
ability. It is not a thing you can ship in JavaScript.
So why do the amber ones play? Because these particular
agencies also publish a browser-friendly copy of the same camera, and this
page quietly uses that instead. It is a second-best version of the feed: a
re-encode, a few seconds behind, and it exists only for as long as the
agency chooses to keep publishing it. What it is not is something you can
hand to another program. You cannot point ATAK, VLC, OBS or a recorder at a
web page. That is the whole gap the desktop app fills — it opens the
RTSP feed itself and re-publishes it as a stream your own tools can open.
This page does not know which cameras are working. The
desktop app probes every camera on a schedule and colours the map by what
actually answered — up, serving a placeholder, or eight months stale.
A static page has nobody to do that probing, so the colours here mean
what kind of feed it is and never whether it is alive. Some of
these are dead. You will find out by clicking them.
Nothing here is recorded, and nothing reaches me. The
camera addresses were baked into this page when it was built. Your browser
fetches the pictures from the agencies directly, so which camera you opened
is between you and them; it does not pass through marshallfrith.com and I
could not log it if I wanted to. Nothing is saved, and closing the tab ends
it.
Be a decent guest. These are public cameras run by public
agencies on budgets that did not plan for this. The page only fetches a
picture while you are actually looking at it, and stops when you close the
panel or switch tabs.
The desktop app covers all 35,944 cameras, not just these
785: what it does and how to run it . It is Python
and ffmpeg, it runs on macOS, Linux and Windows, and it keeps its data on
your machine.
Map data ©
OpenStreetMap
contributors. Camera imagery belongs to the agencies that publish it.
