# obsproject/obs-studio architecture

> Architecture diagram of the GitHub repository obsproject/obs-studio, generated by GitDiagram from its file tree, README and a sample of source files (last updated 2026-06-25). It is an AI-made overview: check details against the source.

- Interactive diagram: https://gitdiagram.com/obsproject/obs-studio
- Repository: https://github.com/obsproject/obs-studio

## Overview

1. **Repository purpose and top-level shape**
   - This is the OBS Studio monorepo: a desktop application plus its media engine, plugin ecosystem, platform-specific capture/rendering backends, and packaging/build automation.
   - The code is split into a few major roots: `libobs` for the core engine, `frontend` for the Qt-based application UI, `plugins` for feature modules, `shared` for reusable support libraries, plus `libobs-*` rendering backends and `test`/CI infrastructure.

2. **Core media engine: `libobs`**
   - `libobs` is the architectural center. It implements the scene model, sources, filters, transitions, outputs, encoders, graphics abstraction, audio/video media I/O, hotkeys, properties, config, threading, and platform utilities.
   - The main data path here is: inputs/sources produce frames and audio -> scenes/compositor mix and render them -> encoders compress -> outputs package and deliver to a destination such as a file or streaming service.

3. **Frontend application layer: `frontend`**
   - `frontend` is the OBS Studio desktop app built on Qt. It owns the main window, dialogs, docks, settings pages, wizards, update UI, plugin manager UI, OAuth/login flows, and the user-facing control surfaces.
   - It talks to `libobs` through the frontend API in `frontend/api` and through higher-level app classes like `OBSApp`, `OBSStudioAPI`, and the main widgets under `frontend/widgets`.

4. **Rendering backends: `libobs-opengl`, `libobs-d3d11`, `libobs-metal`, `libobs-winrt`**
   - Rendering and capture are split by platform/graphics API.
   - `libobs-opengl` provides OpenGL/EGL/X11/Wayland/Cocoa glue; `libobs-d3d11` provides the Windows Direct3D 11 subsystem; `libobs-metal` provides the macOS Metal implementation in Swift; `libobs-winrt` handles Windows Runtime capture pieces.
   - These backends are the boundary between OBS’s portable scene/compositing logic and OS/driver-specific graphics APIs.

5. **Plugin model: feature modules under `plugins/`**
   - Most runtime features are delivered as modules loaded by `libobs`, not hardcoded into the core.
   - Plugins include capture sources (`win-capture`, `mac-capture`, `linux-capture`, `linux-pipewire`, `linux-v4l2`, `win-dshow`, `mac-avcapture`), audio inputs (`win-wasapi`, `linux-pulseaudio`, `linux-alsa`, `oss-audio`, `sndio`, `linux-jack`), encoders (`obs-x264`, `obs-nvenc`, `obs-qsv11`, `obs-libfdk`, `coreaudio-encoder`, `mac-videotoolbox`), outputs (`obs-outputs`, `obs-ffmpeg`, `obs-webrtc`), and UI add-ons (`obs-browser`, `obs-text`, `text-freetype2`, `obs-transitions`, `obs-filters`, `plugin-manager`, etc.).

6. **Windows capture and injection path**
   - `plugins/win-capture` is a major subsystem because Windows game/window/display capture requires hook-based interception.
   - It contains a graphics hook, injected helper, graphics API-specific capture code for D3D8/9/10/11/12, DXGI, OpenGL, and Vulkan, plus helpers for graphics offsets and compatibility data.
   - The data path here is: OBS injects capture helpers into target processes -> hooks the graphics API -> copies frames back to OBS for composition.

7. **macOS capture and virtual camera**
   - macOS support is split across `plugins/mac-capture`, `plugins/mac-avcapture`, `plugins/mac-syphon`, `plugins/mac-videotoolbox`, and `plugins/mac-virtualcam`.
   - These modules cover screen/window/audio capture, Apple capture frameworks, Syphon interoperability, hardware encoding, and the macOS virtual camera implementation.
   - Several pieces are written in Objective-C/Swift, reflecting tight integration with Apple frameworks and the Camera/Driver architectures.

8. **Linux capture and portals**
   - Linux capture is distributed across `linux-capture`, `linux-pipewire`, `linux-v4l2`, `linux-alsa`, `linux-pulseaudio`, `linux-jack`, and `linux-alsa`.
   - Modern desktop capture on Wayland flows through PipeWire and portals, while legacy X11 capture uses Xcomposite/XShm paths.
   - Audio capture is similarly backend-specific, with separate modules for ALSA, PulseAudio, JACK, and sndio.

9. **Encoder/output/service stack**
   - `plugins/obs-ffmpeg`, `plugins/obs-outputs`, `plugins/obs-nvenc`, `plugins/obs-qsv11`, `plugins/obs-libfdk`, and related encoder plugins are responsible for turning rendered media into streamable or recordable bitstreams.
   - `obs-outputs` provides RTMP, FLV, MP4, and null outputs; `obs-ffmpeg` adds FFmpeg-based muxing/encoding paths; `obs-webrtc` adds WHIP/WebRTC streaming; `rtmp-services` supplies service metadata and presets.
   - The output boundary is where scene-rendered media leaves OBS and becomes a file, a network stream, or a device feed.

10. **Sources, filters, transitions, and UI-facing components**
   - `obs-filters`, `obs-transitions`, `image-source`, `text-freetype2`, `vlc-video`, `obs-vst`, and similar modules implement source types and visual/audio processing.
   - These modules plug into the same core source/filter interfaces, so they participate in the shared scene graph and rendering pipeline rather than owning a separate UI stack.
   - Many ship shader/effect assets in `data/` alongside locale files, indicating a mixed runtime of C/C++ code plus declarative GPU effects and translated strings.

11. **Shared support libraries**
   - `shared/` contains reusable infrastructure used across core, frontend, plugins, and tests.
   - Important pieces include IPC and shared-memory queues, file updating, media playback, Qt helper widgets, scripting support for Lua/Python, and small utility libraries like BPM, options parsing, and “happy eyeballs” networking.
   - This layer reduces duplication for functionality that is not part of the core media engine but is needed across many modules.

12. **Build system, dependency management, and platform packaging**
   - The project is CMake-driven (`CMakeLists.txt`, `CMakePresets.json`) with extensive per-platform CMake logic under `cmake/`.
   - `.github/scripts`, `.github/actions`, and workflows handle formatting, analysis, package creation, code signing, docs generation, and platform-specific build steps.
   - Packaging is a first-class concern: there are manifests, appcasts, Steam packaging scripts, Windows signing configs, macOS resources, Flatpak-related validation, and Linux desktop/metainfo files.

13. **Documentation, localization, and assets**
   - `docs/sphinx` contains the developer-facing and API documentation.
   - Translation files are distributed throughout `frontend/data/locale` and each plugin’s `data/locale`, so localization is part of the runtime asset model, not a separate service.
   - Assets such as effects, icons, manifests, themes, and schemas are colocated with the modules that consume them.

14. **Testing and validation**
   - `test/` contains unit/integration-style tests for utility layers and media/input behavior, plus platform-specific test targets.
   - The repository also includes dedicated validation tooling in CI for manifests, services definitions, Qt XML/forms, formatting, and compatibility rules.
   - This makes the architecture strongly contract-driven: shared APIs, plugin schemas, and packaging metadata are continuously validated across the tree.

Main entry points: [`libobs`](https://github.com/obsproject/obs-studio/tree/master/libobs) (libobs), [`frontend`](https://github.com/obsproject/obs-studio/tree/master/frontend) (OBS Studio), [`plugins/win-capture`](https://github.com/obsproject/obs-studio/tree/master/plugins/win-capture) (Windows capture), [`plugins/mac-capture`](https://github.com/obsproject/obs-studio/tree/master/plugins/mac-capture) (macOS capture)

## Diagram (Mermaid)

```mermaid
flowchart TD

subgraph group_core["Core engine"]
  node_libobs[("libobs<br/>media engine")]
  node_libobs_graphics["Graphics<br/>render core"]
  node_libobs_media["Media I/O<br/>media pipeline"]
  node_libobs_util["Utilities<br/>runtime util"]
end

subgraph group_ui["Desktop UI"]
  node_frontend_app[("OBS Studio<br/>Qt app")]
  node_frontend_api["Frontend API<br/>bridge API"]
  node_frontend_widgets["Main UI<br/>ui widgets"]
  node_frontend_utility["UI Support<br/>app services"]
end

subgraph group_backends["Render backends"]
  node_libobs_opengl["OpenGL<br/>GL backend"]
  node_libobs_d3d11["D3D11<br/>Windows backend"]
  node_libobs_metal["Metal<br/>macOS backend"]
  node_libobs_winrt["WinRT capture<br/>capture backend"]
end

subgraph group_plugins["Plugins"]
  node_plugins_root[("Plugins<br/>runtime modules")]
  node_win_capture["Windows capture<br/>capture plugin"]
  node_mac_capture["macOS capture<br/>capture plugin"]
  node_linux_capture["Linux capture<br/>capture plugin"]
  node_pipewire_capture["PipeWire<br/>Wayland capture"]
  node_outputs_stack["Outputs<br/>output plugin"]
  node_ffmpeg_stack["FFmpeg<br/>encoding plugin"]
  node_service_catalog["Services<br/>service metadata"]
  node_filters_sources["Sources & filters<br/>feature plugins"]
end

subgraph group_shared["Shared libs"]
  node_shared_libs[("Shared libs<br/>support libraries")]
end

subgraph group_tooling["Build & CI"]
  node_build_ci["Build & CI<br/>automation<br/>[.github]"]
  node_docs_tests["Docs & tests<br/>validation"]
end

node_frontend_app -->|"uses"| node_frontend_api
node_frontend_widgets -->|"builds UI"| node_frontend_app
node_frontend_utility -->|"supports"| node_frontend_app
node_frontend_app -->|"controls"| node_libobs
node_libobs -->|"renders via"| node_libobs_graphics
node_libobs -->|"moves media"| node_libobs_media
node_libobs -->|"relies on"| node_libobs_util
node_libobs -->|"reuses"| node_shared_libs
node_libobs -.->|"loads backend"| node_libobs_opengl
node_libobs -.->|"loads backend"| node_libobs_d3d11
node_libobs -.->|"loads backend"| node_libobs_metal
node_libobs -.->|"uses"| node_libobs_winrt
node_plugins_root -->|"loads into"| node_libobs
node_win_capture -->|"feeds frames"| node_libobs
node_win_capture -->|"hooks"| node_libobs_d3d11
node_mac_capture -->|"feeds capture"| node_libobs
node_mac_capture -.->|"integrates"| node_libobs_metal
node_linux_capture -->|"feeds capture"| node_libobs
node_pipewire_capture -->|"feeds capture"| node_libobs
node_outputs_stack -->|"exports"| node_libobs
node_ffmpeg_stack -->|"encodes/muxes"| node_libobs
node_service_catalog -.->|"configures"| node_outputs_stack
node_filters_sources -->|"extends"| node_libobs
node_filters_sources -.->|"shown in UI"| node_frontend_app
node_build_ci -->|"packages"| node_frontend_app
node_build_ci -->|"validates"| node_plugins_root
node_docs_tests -.->|"documents/tests"| node_libobs
node_docs_tests -.->|"documents/tests"| node_frontend_api

click node_libobs "https://github.com/obsproject/obs-studio/tree/master/libobs"
click node_libobs_graphics "https://github.com/obsproject/obs-studio/tree/master/libobs/graphics"
click node_libobs_media "https://github.com/obsproject/obs-studio/tree/master/libobs/media-io"
click node_libobs_util "https://github.com/obsproject/obs-studio/tree/master/libobs/util"
click node_frontend_app "https://github.com/obsproject/obs-studio/tree/master/frontend"
click node_frontend_api "https://github.com/obsproject/obs-studio/tree/master/frontend/api"
click node_frontend_widgets "https://github.com/obsproject/obs-studio/tree/master/frontend/widgets"
click node_frontend_utility "https://github.com/obsproject/obs-studio/tree/master/frontend/utility"
click node_libobs_opengl "https://github.com/obsproject/obs-studio/tree/master/libobs-opengl"
click node_libobs_d3d11 "https://github.com/obsproject/obs-studio/tree/master/libobs-d3d11"
click node_libobs_metal "https://github.com/obsproject/obs-studio/tree/master/libobs-metal"
click node_libobs_winrt "https://github.com/obsproject/obs-studio/tree/master/libobs-winrt"
click node_plugins_root "https://github.com/obsproject/obs-studio/tree/master/plugins"
click node_win_capture "https://github.com/obsproject/obs-studio/tree/master/plugins/win-capture"
click node_mac_capture "https://github.com/obsproject/obs-studio/tree/master/plugins/mac-capture"
click node_linux_capture "https://github.com/obsproject/obs-studio/tree/master/plugins/linux-capture"
click node_pipewire_capture "https://github.com/obsproject/obs-studio/tree/master/plugins/linux-pipewire"
click node_outputs_stack "https://github.com/obsproject/obs-studio/tree/master/plugins/obs-outputs"
click node_ffmpeg_stack "https://github.com/obsproject/obs-studio/tree/master/plugins/obs-ffmpeg"
click node_service_catalog "https://github.com/obsproject/obs-studio/tree/master/plugins/rtmp-services"
click node_shared_libs "https://github.com/obsproject/obs-studio/tree/master/shared"
click node_build_ci "https://github.com/obsproject/obs-studio/blob/master/.github"
click node_docs_tests "https://github.com/obsproject/obs-studio/tree/master/docs/sphinx"

classDef toneNeutral fill:#f8fafc,stroke:#334155,stroke-width:1.5px,color:#0f172a
classDef toneBlue fill:#dbeafe,stroke:#2563eb,stroke-width:1.5px,color:#172554
classDef toneAmber fill:#fef3c7,stroke:#d97706,stroke-width:1.5px,color:#78350f
classDef toneMint fill:#dcfce7,stroke:#16a34a,stroke-width:1.5px,color:#14532d
classDef toneRose fill:#ffe4e6,stroke:#e11d48,stroke-width:1.5px,color:#881337
classDef toneIndigo fill:#e0e7ff,stroke:#4f46e5,stroke-width:1.5px,color:#312e81
classDef toneTeal fill:#ccfbf1,stroke:#0f766e,stroke-width:1.5px,color:#134e4a
class node_libobs,node_libobs_graphics,node_libobs_media,node_libobs_util toneBlue
class node_frontend_app,node_frontend_api,node_frontend_widgets,node_frontend_utility toneAmber
class node_libobs_opengl,node_libobs_d3d11,node_libobs_metal,node_libobs_winrt toneMint
class node_plugins_root,node_win_capture,node_mac_capture,node_linux_capture,node_pipewire_capture,node_outputs_stack,node_ffmpeg_stack,node_service_catalog,node_filters_sources toneRose
class node_shared_libs toneIndigo
class node_build_ci,node_docs_tests toneTeal
```

## Components

### Core engine

Portable media engine and scene/compositing runtime.

- [libobs](https://github.com/obsproject/obs-studio/tree/master/libobs): media engine · Core scene graph, sources, filters, transitions, encoders, outputs, graphics, audio/video I/O, hotkeys, and platform utilities. · `libobs`
- [Graphics](https://github.com/obsproject/obs-studio/tree/master/libobs/graphics): render core · Graphics abstraction, effects, math, textures, shaders, and device-independent compositing. · `libobs/graphics`
- [Media I/O](https://github.com/obsproject/obs-studio/tree/master/libobs/media-io): media pipeline · Audio/video buffers, resampling, format conversion, frame handling, and remux helpers. · `libobs/media-io`
- [Utilities](https://github.com/obsproject/obs-studio/tree/master/libobs/util): runtime util · Threading, config, platform, serializers, process/task helpers, and common low-level support. · `libobs/util`

### Desktop UI

Qt-based application layer and user-facing controls.

- [OBS Studio](https://github.com/obsproject/obs-studio/tree/master/frontend): Qt app · Desktop application shell, main window, dialogs, docks, settings, wizards, and update/login flows. · `frontend`
- [Frontend API](https://github.com/obsproject/obs-studio/tree/master/frontend/api): bridge API · Public and internal interface between the frontend app and the core OBS runtime. · `frontend/api`
- [Main UI](https://github.com/obsproject/obs-studio/tree/master/frontend/widgets): ui widgets · Main window widgets, preview, status bar, audio mixer, scene controls, and app chrome. · `frontend/widgets`
- [UI Support](https://github.com/obsproject/obs-studio/tree/master/frontend/utility): app services · Crash handling, output helpers, networking helpers, theme/update logic, and platform integration. · `frontend/utility`

### Render backends

Platform graphics and capture backends.

- [OpenGL](https://github.com/obsproject/obs-studio/tree/master/libobs-opengl): GL backend · OpenGL/EGL/X11/Wayland/Cocoa rendering backend glue. · `libobs-opengl`
- [D3D11](https://github.com/obsproject/obs-studio/tree/master/libobs-d3d11): Windows backend · Direct3D 11 rendering and resource management backend for Windows. · `libobs-d3d11`
- [Metal](https://github.com/obsproject/obs-studio/tree/master/libobs-metal): macOS backend · Swift-based Metal rendering backend and swapchain/device layer. · `libobs-metal`
- [WinRT capture](https://github.com/obsproject/obs-studio/tree/master/libobs-winrt): capture backend · Windows Runtime capture and dispatch support used by Windows capture paths. · `libobs-winrt`

### Plugins

Loadable runtime modules for capture, encoding, output, and effects.

- [Plugins](https://github.com/obsproject/obs-studio/tree/master/plugins): runtime modules · Feature modules loaded by libobs, spanning capture, encoding, outputs, and source/filter add-ons. · `plugins`
- [Windows capture](https://github.com/obsproject/obs-studio/tree/master/plugins/win-capture): capture plugin · Injected hook-based game/window/display capture across multiple graphics APIs. · `plugins/win-capture`
- [macOS capture](https://github.com/obsproject/obs-studio/tree/master/plugins/mac-capture): capture plugin · Screen, window, and audio capture paths for macOS. · `plugins/mac-capture`
- [Linux capture](https://github.com/obsproject/obs-studio/tree/master/plugins/linux-capture): capture plugin · X11 capture helpers and legacy Linux screen/window capture implementation. · `plugins/linux-capture`
- [PipeWire](https://github.com/obsproject/obs-studio/tree/master/plugins/linux-pipewire): Wayland capture · Wayland desktop and camera capture through portals and PipeWire. · `plugins/linux-pipewire`
- [Outputs](https://github.com/obsproject/obs-studio/tree/master/plugins/obs-outputs): output plugin · Streaming, recording, muxing, null output, and RTMP/FLV/MP4 delivery paths. · `plugins/obs-outputs`
- [FFmpeg](https://github.com/obsproject/obs-studio/tree/master/plugins/obs-ffmpeg): encoding plugin · FFmpeg-based muxing, codec integration, and source/output support. · `plugins/obs-ffmpeg`
- [Services](https://github.com/obsproject/obs-studio/tree/master/plugins/rtmp-services): service metadata · Streaming service presets, schemas, and platform-specific ingest metadata. · `plugins/rtmp-services`
- **Sources & filters**: feature plugins · Built-in sources, filters, transitions, text, browser, audio effects, and UI add-ons.

### Shared libs

Reusable support libraries used across the repo.

- [Shared libs](https://github.com/obsproject/obs-studio/tree/master/shared): support libraries · Reusable IPC, scripting, playback, Qt widget, and utility libraries shared across modules. · `shared`

### Build & CI

Build, packaging, docs, and validation infrastructure.

- [Build & CI](https://github.com/obsproject/obs-studio/blob/master/.github): automation · CMake, scripts, workflows, packaging, signing, docs generation, and validation. · `.github`
- [Docs & tests](https://github.com/obsproject/obs-studio/tree/master/docs/sphinx): validation · Sphinx documentation plus unit/integration tests for core utilities and media behavior. · `docs/sphinx`

## Connections

- OBS Studio → Frontend API: uses · UI talks to core through the frontend API.
- Main UI → OBS Studio: builds UI · Main widgets compose the user-facing OBS window.
- UI Support → OBS Studio: supports · App services provide crash handling, updates, and platform glue.
- OBS Studio → libobs: controls · The desktop app configures and drives the media engine.
- libobs → Graphics: renders via · Core compositing and effects depend on the graphics layer.
- libobs → Media I/O: moves media · Media I/O feeds audio/video into the engine and outputs encoded streams.
- libobs → Utilities: relies on · Core runtime uses shared low-level utilities.
- libobs → Shared libs: reuses · Engine and plugins share IPC, scripting, playback, and Qt helpers.
- libobs → OpenGL: loads backend · Portable graphics layer binds to the OpenGL implementation where applicable.
- libobs → D3D11: loads backend · Windows graphics and capture paths use the D3D11 backend.
- libobs → Metal: loads backend · macOS graphics paths use the Metal backend.
- libobs → WinRT capture: uses · Windows Runtime capture support is part of the Windows boundary layer.
- Plugins → libobs: loads into · Runtime modules register sources, filters, encoders, and outputs with the core.
- Windows capture → libobs: feeds frames · Injected helpers capture frames back into the core compositor.
- Windows capture → D3D11: hooks · Windows capture intercepts D3D/OpenGL/Vulkan presentation paths.
- macOS capture → libobs: feeds capture · macOS capture modules deliver screen/window/audio sources to the engine.
- macOS capture → Metal: integrates · macOS capture and rendering closely follow Apple graphics APIs.
- Linux capture → libobs: feeds capture · X11-based Linux capture sources enter the scene pipeline.
- PipeWire → libobs: feeds capture · Wayland/PipeWire desktop capture feeds the core engine.
- Outputs → libobs: exports · Outputs consume rendered/encoded media from the core.
- FFmpeg → libobs: encodes/muxes · FFmpeg paths provide codec and mux integration for the runtime.
- Services → Outputs: configures · Service presets and schemas drive streaming output setup.
- Sources & filters → libobs: extends · Sources, filters, and transitions register with the core scene system.
- Sources & filters → OBS Studio: shown in UI · Feature plugins surface through the application UI and dialogs.
- Build & CI → OBS Studio: packages · CMake, scripts, and workflows build and package the desktop app and modules.
- Build & CI → Plugins: validates · CI checks plugin schemas, manifests, formatting, and platform-specific steps.
- Docs & tests → libobs: documents/tests · Docs and tests describe and verify the core engine contracts.
- Docs & tests → Frontend API: documents/tests · Frontend API docs and validation anchor the app-core interface.