A Pointman extension for OBS: a recording watchdog. While OBS records, it holds each screen capture's picture against the real screen, and when the picture stops while the screen moves, it tells you in a thread within about a minute, with the frozen frame. Then an all-clear when its frames move again.

Why: while James recorded Spacesheep, OBS's display capture froze at 11:14 and kept writing that one frame at 60 fps for the next 1 h 20 min, with no warning: 31 of its 36 minutes of screen footage were lost (Pointman thread 10399). A frozen capture still writes a normal-looking file, only a small one.

One Rust binary, bin/obs, on the pointman-extension crate (the node's typed protocol: each method's params and result are its messages), for macOS (Apple silicon and Intel).

• Reading OBS: obs-websocket v5, built into OBS 28 and later, on 127.0.0.1:4455. It sends only Get… requests (GetRecordStatus, GetCurrentProgramScene, GetSceneItemList, GetInputSettings, GetSourceScreenshot, GetVersion): Obs::request refuses anything else, so it can't change a scene, a source, a profile or the recording. It subscribes to no events.
• What it watches: every macOS Screen Capture (and the older Display Capture and Window Capture) showing in the program scene, through nested scenes and groups, or the one source the source setting names. Hidden items aren't watched.
• A look, every every_seconds (15) while recording and not paused:
  1. the real screen, with macOS's screencapture: the capture's display (by its display_uuid) or window (by its id), then
  2. OBS's picture of the source (GetSourceScreenshot, 640 px across). Each is reduced to a 256-cell-wide grid of colour averages and compared with the last look's. The screen goes first, so a change that lands between the two shows in OBS's and is never taken for a freeze.
• Frozen: OBS's picture hasn't changed at all (no cell by more than 4 of 255) for frozen_seconds (60), while the screen has (0.05% of its cells by more than 12), seen at a look before the latest. A frozen capture is the same texture each time, so its picture doesn't change by a single cell, while a live one shows any move of the screen in many cells.
• Not frozen: a still screen (neither changes), a capture that moves with the screen, OBS's own windows (the parts of them nothing covers are left out of the screen's comparison: their meters and timer move all the time, and a capture that hides OBS never shows them), a locked or sleeping screen (not taken at all), and an application capture (no one picture to compare it with: listed as such).
• The file: GetRecordStatus's outputBytes. The alert says how fast it grew over the last minute (a frozen 60 fps capture wrote 153 MB in 20 min, 0.13 MB/s). A recording that has grown and then doesn't grow for frozen_seconds is an alert of its own ("OBS may have stopped writing it").

In the thread the settings name, as a files.publish of OBS's picture with a post:

The picture is OBS's at 1280 px across; if OBS doesn't give one just then, the look's own (640 px) goes with the alert. A stall's picture is the program scene's, and with none, it's tried again at the next look.

Once per freeze: an alert that's out is kept in the state folder (alerts.json), so a restart doesn't send it again, and the next move is its all-clear.

Not a Needs-you card yet: an extension can't raise one through the node today (only shells and agents' hooks do), so the alert notifies by its @mention. A node method for it is patchbay's, later.

1. OBS: Tools › WebSocket Server Settings › Enable WebSocket server. Keep authentication on.
2. The password: /obs add in any thread opens the app's form, which seals it in the vault as obs.<label> (OBS's Show Connect Info has it). The extension tries each obs. item until OBS takes one. It never reads OBS's config files.
3. Screen Recording: the node needs it (System Settings › Privacy & Security › Screen & System Audio Recording), as for the screen extension. Without it, screencapture takes only the desktop, so a freeze over windows goes unseen.
4. Settings, in ~/.config/pointman/extensions/obs/config.toml (or pointman config set node.extensions.obs.<key> <value>):

With the defaults a freeze alerts 60–75 s after OBS's picture last moved: the 60 s rule, plus up to one look.

Health has two parts. obs: OBS isn't open (stopped), open with its WebSocket server off, asking for a password (needs auth: /obs add), refusing the vault's (needs auth), or ok with the recording's state. watchdog: failing while a capture is frozen or the file has stalled, with no thread set, or with no mention (an alert nobody is told about); else what it watches. The obs.status event says the same when it changes.

cargo test. The tests run obs under the SDK's stand-in node against a fake OBS (an obs-websocket v5 server in the test, with a password or not, answering from a state the test changes) and a fake screen (POINTMAN_OBS_FAKE: the displays, OBS's windows and whether it's locked; POINTMAN_OBS_SCREENCAPTURE: a screencapture that copies the picture the test puts in place), so no test reads this machine's OBS or screen. They look every second and call a picture frozen after 3: a freeze alerts once with its frame and all-clears on the same card, a still screen and a live capture don't, OBS's own windows moving don't, a locked screen waits, the recording stopping says so once, OBS closed, its WebSocket off, no password and a wrong one, a restart mid-freeze, and that only Get… requests are ever sent. src/watch.rs has the judgement's own tests, on looks alone.

tests/real_screen.rs is by hand only (cargo test --release --test real_screen -- --ignored --nocapture): it takes the real main display twice and prints sizes, times and how much changed, then deletes them.

A release is a tag that's extension.toml's version: .github/workflows/release.yml builds both Macs and attaches them.