OBS (macOS) Virtual Camera

Creates a virtual webcam device from the output of OBS Studio. Especially useful for streaming smooth, composited video into Zoom, Hangouts, Jitsi etc. Like CatxFish/obs-virtual-cam but for macOS.

This code was spun out of this OBS Project RFC which was itself spun out of this issue from @tobi. This was intended as a proof of concept to inform technical decisions in that RFC, but who knows, maybe it will be useful to you in its current state. The goal is for this (or something with equivalent functionality) to eventually be merged into the core OBS codebase 🤞.

This is heavily based on Apple's CoreMediaIO sample code which has been modernized by @lvsti

Known Issues

• If OBS is closed when an app is opened, the virtual camera may not show up
• Can't click menu bar after program start (OBS Issue #2678). NOTE: This is not an issue with this plugin, but it does make it more difficult to turn on the Virtual Camera created by this plugin.
• DAL plugin unable to run because of codesigning issues (for example unable to see Virtual Camera in latest version of Zoom). See issue #4 for a workaround
• DAL plugin does not work in Discord (issue #37)

Discussion / Support

The official place for discussion and chat related to this plugin is in the #plugins-and-tools channel in the OBS Studio Discord.

Reporting Issues / Bugs / Improvements

🚀 Wonder How to contribute? Have look at our notes for contributors.

This plugin is still very much a work in progress. If you are having an issue there's a good chance someone has already run into the same thing. Please search past issues before reporting a new one.

Also please confirm that your issue is related to this plugin and not a general OBS problem before opening an issue – try to build OBS locally (but not this plugin) and see if the issue persists. If it does, please don't open an issue here; Instead go open an issue on obsproject/obs-studio. The same goes for supporting other plugins; it's outside of the scope of this project to tell you how to build other OBS plugins (e.g. Browser Source, Speex, etc).

If you still believe you have found an unreported issue related to this plugin, please open an issue! When you do, include any relevant terminal log, crash log, screen recording and/or screenshots.

Building

To use this plugin, you'll need to clone and build OBS locally, build this plugin, copy it to the right places, then run your local build of OBS:

# Clone and build OBS
git clone --recursive https://github.com/obsproject/obs-studio.git
cd obs-studio

# Follow normal OBS build steps
brew install FFmpeg x264 Qt5 cmake mbedtls swig
mkdir build
cd build
export QTDIR=/usr/local/opt/qt
cmake .. && make -j

# Clone this repo
cd ../..
git clone https://github.com/johnboiles/obs-mac-virtualcam.git
cd obs-mac-virtualcam

# Set an environment variable that points to the directory for your OBS clone
export OBS_DIR=$PWD/../obs-studio

# Build the plugin
mkdir build
cd build
cmake -DLIBOBS_INCLUDE_DIR:STRING=$OBS_DIR/libobs -DLIBOBS_LIB:STRING=$OBS_DIR/build/libobs/libobs.dylib -DOBS_FRONTEND_LIB:STRING=$OBS_DIR/build/UI/obs-frontend-api/libobs-frontend-api.dylib -DQTDIR:STRING=/usr/local/opt/qt ..
make -j

# Copy the OBS plugin to your local OBS build
cp src/obs-plugin/obs-mac-virtualcam.so $OBS_DIR/build/rundir/RelWithDebInfo/obs-plugins/

# Remove any existing plugin and copy the DAL plugin to the right place
sudo rm -rf /Library/CoreMediaIO/Plug-Ins/DAL/obs-mac-virtualcam.plugin && sudo cp -r src/dal-plugin/obs-mac-virtualcam.plugin /Library/CoreMediaIO/Plug-Ins/DAL

# Run your build of OBS
cd $OBS_DIR/build/rundir/RelWithDebInfo/bin
./obs

Now in OBS go to Tools→Start Virtual Camera, then open your favorite video streaming app (or fully close it then re-open it to make sure it reloads any loaded video plugins). You should be able to pick OBS Virtual Camera as a source.

Development

Please help me make this thing not janky!

Using the cmake Xcode generator

You can use cmake to generate an xcodeproj file to open all the files in Xcode:

# Set an environment variable that points to the directory for your OBS clone
export OBS_DIR=$PWD/../obs-studio
# Set an environment variable pointing to QT
export QTDIR=/usr/local/opt/qt

mkdir xcode
cd xcode
cmake -DLIBOBS_INCLUDE_DIR:STRING=$OBS_DIR/libobs -DLIBOBS_LIB:STRING=$OBS_DIR/build/libobs/libobs.dylib -DOBS_FRONTEND_LIB:STRING=$OBS_DIR/build/UI/obs-frontend-api/libobs-frontend-api.dylib -DQTDIR:STRING=/usr/local/opt/qt -G Xcode ..

You can then use Xcode to build your binaries (which will include debug symbols). To copy them into the right place you need a slightly different command. From the xcode directory created previously:

# Copy over the OBS plugin
cp src/obs-plugin/Debug/obs-mac-virtualcam.so $OBS_DIR/xcode/rundir/Debug/obs-plugins
# Remove any existing plugin and copy the DAL plugin to the right place
sudo rm -rf /Library/CoreMediaIO/Plug-Ins/DAL/obs-mac-virtualcam.plugin && sudo cp -r src/dal-plugin/Debug/obs-mac-virtualcam.plugin /Library/CoreMediaIO/Plug-Ins/DAL

Debugging the OBS plugin

To debug the OBS plugin (obs-mac-virtualcam.so), you can attach the Xcode debugger to the OBS process. This allows you to step through the OBS plugin code In Xcode, go to Debug → Attach to Process by PID or Name..., then enter obs and debug the process as root. Then run OBS and you should be able to hit breakpoints set inside the plugin code.

Debugging the DAL plugin

Debugging the DAL plugin (obs-mac-virtualcam.plugin) is a little trickier. You need to attach the Xcode debugger to a host process that loads the plugin. One option is to build another copy of OBS (without obs-mac-virtualcam.so), attach the debugger to that process, then add the virtual camera as a Video Capture Device there. You should then be able to step through code on the DAL plugin.

License

As the goal of this repo is to eventually get merged into obsproject/obs-studio (or die because someone made a better implementation), the license for this code mirrors the GPLv2 license for that project.