Stream to multiple RTMP / SRT / WHIP endpoints simultaneously from a single OBS Studio scene. This is a ground-up C++20 rewrite of sorayuki/obs-multi-rtmp, installable side-by-side with the original.

Built on the OBS plugin template. Same persistence format as upstream — your old configs load without migration.

The upstream plugin works, but the codebase had grown organically and was hard to reason about:

• shared_ptr for every config struct
• A single 1,163-line edit dialog re-implementing OBS's property UI by hand
• Manual obs_*_release calls sprinkled throughout business logic
• File-scope singletons for config and UI-thread posting
• Mixed concerns: one class was both a QWidget and an OBS signal handler

This fork rewrites every line of src/ from scratch with a cleaner architecture, then proves it by building cleanly on macOS, Windows, and Linux with the same CI pipeline the original uses.

See oldsrc/ for the preserved upstream source, and git log rewrite/from-scratch for the full rewrite history.

src/
├── Plugin.cpp           module entry, dock registration
├── Logging.h            blog() macros
├── ObsPtr.h             RAII smart pointers for obs_*_t handles
├── Config.{h,cpp}       value-type model + JSON persistence
├── Protocols.{h,cpp}    RTMP / SRT / WHIP registry
├── OutputSession.{h,cpp}  one streaming target: state machine + stats
└── ui/
    ├── Dock.{h,cpp}           main dock widget
    ├── TargetRow.{h,cpp}      one row per target
    ├── PropertiesView.{h,cpp} obs_properties_t → QFormLayout
    └── EditDialog.{h,cpp}     add/edit modal

Design principles applied throughout:

• RAII over every OBS handle. No manual obs_*_release outside ObsPtr.h.
• Value types for config. No shared_ptr soup.
• Strict separation of concerns. OutputSession has zero Qt dependencies; TargetRow has zero direct OBS API calls.
• UI thread marshalling via std::function. OBS signals post to Qt via an injected UiPoster, not a global singleton.
• No globals. Dock owns the MultiOutputConfig directly.
• C++20 idioms. std::erase_if, contains, designated initializers, std::span, string_view at boundaries.

This plugin is namespaced with an -aa suffix everywhere it would otherwise collide with the upstream plugin:

Install both simultaneously and they will not touch each other's state.

Download the latest macOS build from the Actions tab → pick a successful run → scroll to Artifacts → grab obs-multi-rtmp-aa-<version>-macos-universal-<sha>.

Then run the provided installer script:

./scripts/install-macos.sh

It will:

1. Auto-find the newest obs-multi-rtmp-aa*.zip in ~/Downloads
2. Unwrap the nested .zip → .tar.xz → .plugin bundle
3. Print the architectures to confirm it's a universal binary
4. Quit OBS if it's running (with confirmation)
5. Copy the bundle into ~/Library/Application Support/obs-studio/plugins/
6. Strip com.apple.quarantine so Gatekeeper doesn't silently reject it

You can also pass an explicit path:

./scripts/install-macos.sh path/to/obs-multi-rtmp-aa.zip
./scripts/install-macos.sh path/to/obs-multi-rtmp-aa.plugin

After install, open OBS → Docks → enable Multiple output AA.

Download obs-multi-rtmp-aa-<version>-windows-x64-<sha> from the Actions artifacts, unzip, and run obs-multi-rtmp-aa-<version>-Installer.exe.

Download the Ubuntu artifact and install the .deb:

sudo dpkg -i obs-multi-rtmp-aa_*.deb

# macOS
cmake --preset macos
cmake --build build_macos --config RelWithDebInfo

# Windows
cmake --preset windows-x64
cmake --build build_x64 --config RelWithDebInfo

# Ubuntu
cmake --preset ubuntu-x86_64
cmake --build build_x86_64

Deps (OBS sources, libobs prebuilt, Qt6 prebuilt) are fetched automatically by the OBS plugin template during configure.

Requires:

• CMake 3.28+
• On macOS: Xcode 15+ (the preset uses the Xcode generator)
• On Windows: Visual Studio 2022
• On Linux: GCC 12+ or Clang 15+

• ✅ Builds clean on macOS, Windows, Ubuntu (GitHub Actions)
• ✅ Feature parity with upstream for RTMP / SRT / WHIP outputs
• ✅ Loads upstream configs unchanged
• ⚠️ Not code-signed — macOS builds require xattr -dr com.apple.quarantine (the install script does this)
• 🚧 Per-target scene override and per-track audio mapping are supported by the config layer and by the streaming pipeline, but not exposed in the edit dialog UI yet (the v1 pass kept the dialog minimal). Edit obs-multi-rtmp-aa.json in your profile directory to use them until the UI catches up.

• Original plugin: SoraYuki — sorayuki/obs-multi-rtmp
• Rewrite: Ahmad Awais
• OBS Studio plugin template: https://github.com/obsproject/obs-plugintemplate

GPL-2.0-or-later, matching upstream. See LICENSE.