# obs-streamer-tools-plugin Native OBS Studio source plugin that pulls streamer-tools camera feeds directly from LiveKit over WebRTC, replacing the current SRT/RTSP-via-VLC-or- Media-Source path for directors. Full design: `docs/superpowers/specs/2026-09-06-obs-camera-plugin-design.md` in the `streamer-tools` repo. ## Status **Release/distribution of built binaries is blocked pending owner sign-off.** This plugin statically/dynamically pulls in Google WebRTC and OpenH264 code through the LiveKit SDK, and this repository's own top-level `LICENSE` is GPLv2 while the vendored LiveKit binaries are Apache-2.0 — both a real patent/ royalty question (OpenH264/WebRTC) and a real license-compatibility question (GPLv2 vs. Apache-2.0-linked code) that only the project owner can decide. Nothing in this repo should be built into a package and handed out, posted, or attached to a public release until that sign-off happens. See `third_party/livekit/README.md` for the specifics of what is and is not currently known/shipped on the licensing side. (CI in `.gitea/workflows/build.yml` currently only builds, tests, and uploads CI-internal build artifacts — it does not create a Gitea Release or otherwise publish anything publicly; if that ever changes, the new step must carry this same gate.) The plugin is **functionally complete on Linux and verified end to end there** (module loads into real libobs, connects to a real LiveKit server through the real streamer-tools API shape, and pushes decoded frames into `obs_source_output_video`/`_audio`). It has **not been run in the OBS GUI on any platform.** macOS builds the real module in CI but its artifact is not yet loadable (see the macOS packaging gap under CI). Windows CI has **failed on every completed run so far**. The `-A x64` argument fix is now confirmed working — the run carrying it got as far as building libobs — but it exposed a deeper blocker: OBS 30.0.2's opt-in modern CMake path never defines the `OBS::w32-pthreads` target its own Windows libobs links against. The PowerShell rewrite of the Windows steps is still queued and unproven. See "Where the Windows bootstrap got to" under CI below for the trace and the options, and check current CI status rather than trusting this paragraph's age. See "What is verified, and how" below for exactly what has and has not been checked, and "Testing this by hand" for what a human still needs to do. ## Layout ``` cmake/LiveKitSDK.cmake - downloads + unpacks the pinned client-sdk-cpp release core/ - core library (C++17, no OBS dependency, headless-testable) include/stplugin/ core.h version + ConnectionConfig json.h small strict JSON reader http.h injectable HTTP client interface api_client.h the two /api/obs/:slug/* calls session_types.h media/state types + the pure session logic session.h LiveKitSession, the livekit::Room wrapper src/ http_curl.cpp libcurl backend (Linux/macOS) http_winhttp.cpp WinHTTP backend (Windows) tests/ dependency-free CTest suites obs-adapter/ - thin OBS glue (C++) src/plugin-main.cpp obs_source_info, properties UI, frame output data/locale/en-US.ini scripts/livekit-dev-room.py - mints tokens for the integration test third_party/livekit/ - redistribution notices for the LiveKit binaries .gitea/workflows/build.yml - 3-platform CI matrix ``` ## How it works 1. The operator fills in the streamer-tools server URL, room slug and read key, and picks a camera from the dropdown. 2. The source's own worker thread calls `POST /api/obs/:slug/token?key=…` to mint a hidden, subscribe-only LiveKit token (identity `obs::` — a fresh nonce per mint, so two OBS installs watching the same room can never kick each other). 3. `LiveKitSession` connects `livekit::Room` to the returned `wsUrl`, waits for the chosen participant's `Source.Camera` video track (and their microphone), and reads decoded frames off `VideoStream`/`AudioStream`. 4. The adapter hands those straight to `obs_source_output_video` / `obs_source_output_audio`. Nothing on the OBS UI thread ever blocks on the network. The one deliberate exception is the "Refresh camera list" button, which the operator pressed and is waiting on; it uses a shortened 5s timeout. ### Design decisions worth knowing before changing this - **Frames come from `VideoStream::fromTrack` with our own reader threads, not from `Room::setOnVideoFrameCallback`.** The dispatcher API is keyed by (participant identity, track *name*), which is only knowable once the track is published — and disassembly of `liblivekit.so` 1.10.1 confirms that neither `Room::setOnVideoFrameCallback` nor the dispatcher's own version starts a reader for an already-subscribed track; they only record the registration. Registering at the only moment the name exists would therefore have silently produced no video. - **Every stream operation runs on one owned worker thread**, never on a LiveKit room event thread: `Room::disconnect()` from inside a delegate callback is documented to deadlock. - **`VideoStream::Options::capacity` is 3**, making the SDK queue a drop-oldest ring buffer. A stalled consumer can only fall three frames behind and then sees the *newest* frame, not a backlog — the structural answer to the stale-media bug that motivated this plugin. - **Video and audio are both timestamped with `os_gettime_ns()` at arrival.** The SDK gives video a WebRTC capture timestamp and audio none; mixing two epochs inside one OBS source would guarantee A/V drift. This relies on the SDK's jitter buffering having already aligned them — the assumption the design doc flags for verification on real hardware. **Still unverified.** - **WebRTC changes resolution mid-stream.** Observed directly in the integration test: the first frames after (re)subscribing arrive at a downscaled spatial layer before ramping to the published size. The adapter passes each frame's own geometry through, and logs geometry changes. ## Building Linux (the platform that is fully verified). `STPLUGIN_BOOTSTRAP_OBS=OFF` skips the macOS/Windows OBS-SDK bootstrap, which Linux does not need: ``` sudo apt-get install -y cmake ninja-build libobs-dev libcurl4-openssl-dev cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DSTPLUGIN_BOOTSTRAP_OBS=OFF cmake --build build ctest --test-dir build --output-on-failure ``` The configure step downloads the pinned `client-sdk-cpp` release (~13 MB) into `build/_deps/livekit-sdk`. Point `-DSTPLUGIN_LIVEKIT_SDK_DIR=` at a persistent directory to cache it across builds; `-DSTPLUGIN_LIVEKIT_SDK_VERSION` and `-DSTPLUGIN_LIVEKIT_SDK_TRIPLE` override the pin and the release triple. The build stages a runnable layout into `build/package/`: ``` build/package/bin/64bit/streamer-tools-camera.so (RPATH=$ORIGIN) build/package/bin/64bit/liblivekit.so build/package/bin/64bit/liblivekit_ffi.so build/package/data/locale/en-US.ini build/package/licenses/... ``` That is exactly the layout OBS searches on Linux and Windows — `/obs-studio/plugins//bin/64bit` plus a sibling `data/`, per `AddExtraModulePaths()` in obs-studio's `UI/window-basic-main.cpp` — so `build/package/` is a straight drop-in. The module resolves the LiveKit libraries from `$ORIGIN` (verified: `ldd` on the staged copy resolves both to `bin/64bit/`), not from the build tree. macOS is not this shape; see the macOS packaging gap under CI. ## Testing this by hand **Nobody has yet run this in the OBS GUI. That test is still outstanding on all three platforms.** To do it on Linux: ``` mkdir -p ~/.config/obs-studio/plugins/streamer-tools-camera cp -r build/package/bin build/package/data \ ~/.config/obs-studio/plugins/streamer-tools-camera/ obs ``` (That yields `.../streamer-tools-camera/bin/64bit/streamer-tools-camera.so` and `.../streamer-tools-camera/data/locale/en-US.ini`, which is what OBS looks for.) Then: Sources → `+` → "streamer-tools Camera" → fill in the server URL, room slug and read key from the room's settings page → "Refresh camera list" → pick a camera. Check `~/.config/obs-studio/logs/` for `[streamer-tools-camera] connected to …` and `[streamer-tools-camera] video frame WxH I420`. What to look for that automated testing could not answer: - Does video actually *appear*, right way up, right colours? - Is A/V sync acceptable? (see the timestamp caveat above) - What is the end-to-end latency versus the existing egress path? - Does a publisher restarting mid-show recover cleanly on screen? ### Running the LiveKit integration test `core/tests/test_integration_livekit` publishes a synthetic camera into a real room and subscribes to it through the wrapper. It skips unless `STPLUGIN_IT_*` is set: ``` livekit-server --dev --bind 127.0.0.1 & eval "$(python3 scripts/livekit-dev-room.py)" ctest --test-dir build -R test_integration_livekit --output-on-failure ``` ## What is verified, and how Verified on Ubuntu 24.04 (libobs 30.0.2, client-sdk-cpp 1.10.1, livekit-server 1.13.6 in dev mode): | Claim | How it was checked | |---|---| | The pinned LiveKit SDK links and is callable | `test_livekit_smoke`: `initialize()`/`shutdown()` round-trip, header version asserted equal to the CMake pin | | The JSON reader handles real and hostile input | `test_json`, 158 checks, including truncated bodies, HTML error pages, binary garbage, lone surrogates, and a depth-limit case | | The API client parses the real response shapes and every error branch | `test_api_client`, 127 checks, against a fake HTTP client **and** a real loopback HTTP server driving the actual platform backend | | A dead/stalled/garbage server cannot hang or crash the plugin | loopback cases: truncated JSON, connection closed with no reply, non-HTTP bytes, dead port, stalled server cut off by the client timeout | | Session state transitions, track selection, frame geometry | `test_session`, 81 checks, plus real `connect()` failures against the real SDK | | **Media actually flows** | `test_integration_livekit` against a real LiveKit server: 36 video frames + 323 audio frames, correct I420 geometry and plane pointers, publisher unpublish → `hasVideo()` false with **no further frames from the dead publisher**, republish → video resumes | | **The module loads into real libobs and pushes frames** | a headless libobs harness (`obs_startup` + `obs_reset_audio`/`obs_reset_video` + `obs_open_module`) driving the built module against a stand-in streamer-tools API in front of a real LiveKit server. Log: `connected to ws://… watching cam-test` then `video frame 640x360 I420`; the camera dropdown populated as `Test Camera` / `Dark Camera (offline)`; status `connected`; clean destroy and unload | | A wrong read key is reported, not silently swallowed | same harness with a bad key: status `unknown room slug, or the read key is wrong or has been rotated`, warning info type, retry with backoff, no crash | | Changing the selected camera reconnects cleanly | same harness: switch to a dark slot and back. Each switch mints a fresh `obs::` identity and reconnects; video returns; status stays `connected`; no crash, no stale frame | | Two sources in one OBS process | same harness with a second source added: both connect with distinct nonce identities, both receive frames, both tear down cleanly | **Not verified anywhere:** - The OBS GUI, on any platform. No human has looked at this in OBS. - macOS beyond "CI builds and links the real module and the core tests pass". Its artifact is a bare `.so` with a relative libobs install name and will not load in OBS.app — see the macOS packaging gap under CI. - Windows beyond "the core library and the WinHTTP backend compile and their tests pass", from runs predating the current fixes. The WinHTTP backend has never run against a real streamer-tools server, only against the loopback test server in `test_api_client`. - A/V sync and end-to-end latency against the existing egress path. - Behaviour against the real production streamer-tools server (only against a stand-in serving the same shapes). - Token expiry after an hour. Expiry is handled *reactively*: a fatal disconnect makes the worker mint a fresh token and reconnect. The design doc's "proactively refreshed before expiry" is **not** implemented — `client-sdk-cpp` 1.10.1 exposes no way to hand a live `Room` a new token. ## CI `.gitea/workflows/build.yml` runs on every push, matrixed across the three runners available to this repo under the `CyberCoveLLC` org. | Job | `runs-on` | Runner | State | |---|---|---|---| | `linux` | `ubuntu-24.04` | `localhost.localdomain` | **Green.** Builds the real adapter against Ubuntu's libobs-dev 30.0.2, runs all six test suites, uploads `build/package` as an artifact | | `macos` | `macos-latest` | `home-mac` (Global) | **Green.** Builds libobs 30.0.2 from source, then the real adapter; 6/6 tests; artifact uploaded. But see the macOS packaging gap below | | `windows` | `windows-latest` | `winvm-builder` (org-scoped) | **Failing** — every completed run on this branch has failed. The latest gets as far as building libobs and stops on an OBS-side `OBS::w32-pthreads` target that its own modern CMake path never defines; see below | The Linux job is pinned to `ubuntu-24.04` rather than `ubuntu-latest`: this instance's two Linux runners answer `ubuntu-latest` with different releases, and 22.04's `libobs-dev` is OBS 27 — a different API surface, and the LiveKit SDK's own `linux-x64` asset does not even link there (hence the `ubuntu-22.04` SDK triple; see `cmake/LiveKitSDK.cmake`). macOS and Windows use the `obsproject/obs-plugintemplate` buildspec bootstrap, trimmed to drop `qt6` (this plugin's properties UI is plain `obs_properties_*`), with `obs-studio.version` pinned to 30.0.2 — the same version Linux builds against, and deliberately low, because OBS rejects a module built against a newer libobs than the one running it. **Both jobs fall back to a core-library-only build if the bootstrap fails**, rather than going red, with a workflow `::warning::` and a "Show what was built" step that reports no module. That fallback exists because the bootstrap is the least verifiable part of this project — there is no way to exercise a macOS or Windows OBS build from the Linux development machine — and a permanently red CI teaches people to ignore CI. **Do not remove the warning:** a green job that quietly stopped building the plugin is worse than a red one. ### Where the macOS bootstrap actually got to Six CI iterations, each fixing a real failure visible in the logs: 1. Upstream's Xcode generator → `No CMAKE_C_COMPILER could be found` (the runner has the Command Line Tools, not Xcode). Switched to Ninja. 2. OBS's SDK version regex only matches a full-Xcode SDK path. Synthesised a `MacOSX.platform/Developer/SDKs/MacOSX.sdk` symlink to the same SDK. 3. The install walked into `UI/obs-frontend-api`, whose binary is deliberately never built. The install's exit code is now tolerated. 4. Restricting the install to `libobs/` fixed that but lost the per-configuration export file. 5. `xattr -r -d com.apple.quarantine` followed the SDK symlink into the read-only system SDK. Symlink moved to the build directory; the xattr step is no longer fatal. 6. `IMPORTED_LOCATION or IMPORTED_IMPLIB not set for imported target OBS::libobs configuration Release` — OBS 30.0.2 installs `libobsTargets.cmake` without the per-config file that carries the library path. The top-level `CMakeLists.txt` now detects a locationless `OBS::libobs` and points it at the framework the bootstrap just built. All six are confirmed fixed: the macOS job now downloads obs-deps and obs-studio, builds libobs from source, builds and links the real adapter, passes 6/6 tests, and uploads its artifact. `otool -L` on the result shows it linked against libobs and `@rpath/liblivekit.dylib`. ### macOS packaging gap (known, unfixed) **The macOS artifact will not load in OBS.app as it stands.** Two reasons, neither of which CI can catch, because CI only proves it compiles and links: 1. It is a bare `streamer-tools-camera.so`. OBS on macOS loads plugins as `.plugin` bundles (`Contents/MacOS/`, `Contents/Resources/`, an `Info.plist`), which is what obs-plugintemplate's `cmake/macos/helpers.cmake` builds and which this project deliberately did not vendor. 2. `otool -L` shows the libobs dependency recorded as the relative path `libobs/libobs.framework/Versions/A/libobs`, inherited from the from-source libobs's own install name. A real plugin needs `@rpath/libobs.framework/Versions/A/libobs` plus an `LC_RPATH` pointing at `OBS.app/Contents/Frameworks`. Fixing this means either vendoring the template's macOS bundle helpers or adding an `install_name_tool` pass and a bundle layout — bounded work, but work that has to be done and checked on an actual Mac. It is deliberately not attempted here rather than guessed at. ### Where the Windows bootstrap got to Windows is by far the slowest job — the `lukka/get-cmake` step alone takes 7-15 minutes on `winvm-builder`, and the runner serialises jobs, so a burst of pushes leaves a queue that takes an hour to drain. **The honest record: every completed Windows CI run on this branch has failed.** The first 7 failures were all at commits predating the `-A x64` fix below. The 8th, at `edb0c02` — the first commit that actually carries that fix — has since completed, and it is the informative one: **the `-A x64` fix worked, and Windows failed further along, on something else.** The PowerShell rewrite is still queued behind it and remains unproven. Do not read either fix below as "confirmed"; check current CI status rather than trusting this paragraph's age. What `edb0c02` showed: obs-deps and Qt6 downloaded, CEF skipped, the OBS sub-configure ran for 53s and correctly reported "Plugin Support" and "User Interface" disabled — then failed at generate time: ``` CMake Error at libobs/cmake/os-windows.cmake:46 (target_link_libraries): Target "libobs" links to: OBS::w32-pthreads but the target was not found. ``` **That looks like a genuine hole in OBS 30.0.2's opt-in modern CMake path on Windows, not something this repo is doing wrong.** Traced at the 30.0.2 tag: - `libobs/cmake/os-windows.cmake` links `OBS::w32-pthreads`; - that target is defined only by `deps/w32-pthreads/CMakeLists.txt`, reached only through `deps/CMakeLists.txt`; - `deps/` is added only by the **legacy** branch of the top-level `CMakeLists.txt`. The modern branch — the one `-DOBS_CMAKE_VERSION=3.0.0` selects — adds `libobs`, `libobs-d3d11`, `libobs-winrt`, `libobs-opengl`, `plugins`, `test/test-input` and `UI`, never `deps`; - `libobs/CMakeLists.txt` adds only `deps/libcaption` and `deps/uthash`; - `plugins/CMakeLists.txt` returns immediately under `ENABLE_PLUGINS=OFF`, and does not add `deps/` even when enabled. macOS is unaffected because its libobs does not link w32-pthreads. At 30.0.2 the modern path was the *default* only on macOS (`if(CMAKE_HOST_SYSTEM_NAME MATCHES "(Darwin)" OR OBS_CMAKE_VERSION ...)`), which is consistent with the Windows side of it being under-exercised upstream. Deliberately **not** "fixed" by bumping the pin: 30.0.2, 30.1.2, 30.2.3, 31.0.3 and 31.1.1 were all checked, and every one still links `OBS::w32-pthreads` from `libobs/cmake/os-windows.cmake` while none of them add `deps/w32-pthreads` from `libobs/CMakeLists.txt`. A version bump is therefore not obviously the answer and needs checking rather than assuming. Options, roughly in order of preference: 1. Work out how obs-plugintemplate's own Windows CI satisfies this target at its 31.1.1 pin — it builds `obs-frontend-api` rather than `libobs`, which may pull in a different subdirectory set. If so, building that target (and accepting the Qt dependency on Windows only) is the smallest change. 2. Have the bootstrap add `add_subdirectory(deps/w32-pthreads)` to the extracted OBS tree before configuring. Effective, but a patch against a third-party tree that must be carried across pin bumps. 3. Drop the from-source libobs on Windows and find a prebuilt OBS SDK. Two bugs of its own were found; the first is now proven fixed by `edb0c02` getting past it, the second is still unproven: 1. Upstream passes `-A x64,version=` to the OBS sub-configure, and with a current CMake that `,version=` suffix reappears verbatim in the sub-build's `CMAKE_VS_PLATFORM_NAME` — which obs-studio's own dependency downloader uses as the architecture, sending it after `windows-deps-2023-11-03-x64,version=10.0.26100.0.zip`: ``` string sub-command JSON member 'hashes windows-x64,version=10.0.26100.0' not found Unable to download .../windows-deps-2023-11-03-x64,version=10.0.26100.0.zip ``` Plain `-A x64` now. **Confirmed fixed:** the `edb0c02` run got past this and downloaded `windows-deps-2023-11-03-x64.zip` correctly. 2. The Windows CI steps were originally written in bash (via `shell: bash`), which is a poor fit for a `windows-latest` runner's default toolchain expectations; they were rewritten in PowerShell. **Still unproven** — no completed run has included it. Until a Windows run completes green, Windows should be treated as unverified beyond "the core library and the WinHTTP backend compile and their tests pass", which earlier (failing-job) runs did show before failing later in the job. The `w32-pthreads` blocker above is the next thing to solve, and it is upstream's problem to work around rather than a defect in this repo's bootstrap.