# Build Guide

This document describes how to build Oak Video Editor from source on Windows, Linux, and macOS.

## Prerequisites

- CMake 3.20+
- Ninja (recommended)
- Qt 6 (with private headers)
- FFmpeg 8.0+ development libraries (distro packages on Ubuntu/Debian are often too old; see the Linux section below)
- OpenImageIO
- OpenColorIO (2.x)
- OpenEXR
- Expat
- PortAudio
- OpenGL headers
- Vulkan SDK (optional, required for the Vulkan render backend)
- XKB common (Linux)

---

## Windows (MSYS2)

This guide uses [MSYS2](https://www.msys2.org/) with the UCRT64 toolchain.

### 1. Install MSYS2

Download and install MSYS2 from [https://www.msys2.org/](https://www.msys2.org/). Then open the **MSYS2 UCRT64** terminal.

### 2. Install Dependencies

```bash
pacman -Syu
pacman -S --needed \
  mingw-w64-ucrt-x86_64-cmake \
  mingw-w64-ucrt-x86_64-ninja \
  mingw-w64-ucrt-x86_64-qt6-base \
  mingw-w64-ucrt-x86_64-qt6-tools \
  mingw-w64-ucrt-x86_64-ffmpeg \
  mingw-w64-ucrt-x86_64-openimageio \
  mingw-w64-ucrt-x86_64-opencolorio \
  mingw-w64-ucrt-x86_64-openexr \
  mingw-w64-ucrt-x86_64-fmt \
  mingw-w64-ucrt-x86_64-expat \
  mingw-w64-ucrt-x86_64-portaudio \
  mingw-w64-ucrt-x86_64-vulkan-headers \
  mingw-w64-ucrt-x86_64-vulkan-loader \
  mingw-w64-ucrt-x86_64-gcc
```

> **Note:** Qt 6 private headers may require additional packages depending on the MSYS2 repository state. If CMake reports missing private headers, install `mingw-w64-ucrt-x86_64-qt6-base-private` if available.

### 3. Clone and Build

```bash
# Clone the repository
git clone --recursive https://github.com/OakVideoEditorCommunity/oak.git
cd oak

# Configure
cmake -S . -B build -G Ninja \
  -DCMAKE_BUILD_TYPE=Release \
  -DBUILD_QT6=ON

# Build
cmake --build build --config Release
```

### 4. Run Tests (Optional)

```bash
ctest --test-dir build --output-on-failure -C Release
```

---

## Linux

### Debian / Ubuntu

Install dependencies (FFmpeg is built from source below because distro packages are often too old):

```bash
sudo apt-get update
sudo apt-get install -y \
  cmake ninja-build pkg-config nasm \
  qt6-base-dev qt6-base-dev-tools qt6-base-private-dev qt6-tools-dev qt6-tools-dev-tools \
  libopencolorio-dev libopenimageio-dev libopenexr-dev libexpat1-dev \
  portaudio19-dev libgl1-mesa-dev libvulkan-dev vulkan-headers libxkbcommon-dev
```

Build FFmpeg 8.0+ from source:

```bash
git clone --branch n8.1.1 --depth 1 https://git.ffmpeg.org/ffmpeg.git ffmpeg-src
cd ffmpeg-src
./configure \
  --prefix="$PWD/../ffmpeg-install" \
  --enable-static \
  --disable-shared \
  --disable-doc \
  --disable-programs \
  --disable-avdevice \
  --disable-network \
  --enable-pic \
  --enable-gpl \
  --enable-version3
make -j$(nproc)
make install
cd ..
```

Configure and build:

```bash
cmake -S . -B build -G Ninja \
  -DBUILD_TESTS=ON -DBUILD_QT6=ON \
  -DFFMPEG_ROOT="$PWD/ffmpeg-install"
cmake --build build --config Release
```

Run tests:

```bash
ctest --test-dir build --output-on-failure -C Release
```

### Fedora

Install dependencies:

```bash
sudo dnf install -y \
  cmake ninja-build pkgconf-pkg-config \
  qt6-qtbase-devel qt6-qtbase-private-devel qt6-qttools-devel \
  ffmpeg-free-devel \
  OpenImageIO-devel \
  OpenColorIO-devel \
  openexr-devel \
  expat-devel \
  portaudio-devel \
  mesa-libGL-devel \
  vulkan-headers \
  vulkan-loader-devel \
  libxkbcommon-devel \
  gcc-c++ \
  bzip2-devel
```

Configure and build:

```bash
cmake -S . -B build -G Ninja -DBUILD_TESTS=ON -DBUILD_QT6=ON
cmake --build build --config Release
```

Run tests:

```bash
ctest --test-dir build --output-on-failure -C Release
```

### Arch Linux

Install dependencies:

```bash
sudo pacman -Syu
sudo pacman -S --needed \
  cmake ninja pkgconf \
  qt6-base qt6-tools \
  ffmpeg \
  openimageio \
  opencolorio \
  openexr \
  expat \
  portaudio \
  mesa \
  vulkan-headers \
  vulkan-icd-loader \
  libxkbcommon \
  gcc
```

> **Note:** On Arch Linux, Qt 6 private headers are included in the `qt6-base` package.

Configure and build:

```bash
cmake -S . -B build -G Ninja -DBUILD_TESTS=ON -DBUILD_QT6=ON
cmake --build build --config Release
```

Run tests:

```bash
ctest --test-dir build --output-on-failure -C Release
```

---

## macOS (Non-Official Support)

Note: macOS support is **non-official**. We only run CI automation on macOS and do not perform manual testing.

Install dependencies:

```bash
brew update
brew install cmake ninja pkg-config qt@6 ffmpeg openimageio opencolorio openexr portaudio expat molten-vk vulkan-headers
```

Build OpenTimelineIO (optional, required for OTIO support):

```bash
git clone --depth 1 --branch v0.16.0 https://github.com/PixarAnimationStudios/OpenTimelineIO.git
cmake -S OpenTimelineIO -B OpenTimelineIO/build -G Ninja \
  -DOTIO_SHARED_LIBS=ON \
  -DOTIO_PYTHON_BINDINGS=OFF \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_INSTALL_PREFIX="${PWD}/otio-install"
cmake --build OpenTimelineIO/build
cmake --install OpenTimelineIO/build
```

Configure and build:

```bash
export PATH="$(brew --prefix qt@6)/bin:$PATH"
export CMAKE_PREFIX_PATH="$(brew --prefix qt@6)"
export OTIO_LOCATION="${PWD}/otio-install"
export OCIO_LOCATION="$(brew --prefix opencolorio)"

cmake -S . -B build -G Ninja -DBUILD_TESTS=ON -DBUILD_QT6=ON \
  -DOTIO_LOCATION="${OTIO_LOCATION}" \
  -DOCIO_LOCATION="${OCIO_LOCATION}"
cmake --build build --config Release
```

Run tests:

```bash
ctest --test-dir build --output-on-failure -C Release
```

---

## Build Options

| Option | Default | Description |
|--------|---------|-------------|
| `BUILD_TESTS` | `OFF` | Build unit tests |
| `BUILD_DOXYGEN` | `OFF` | Build Doxygen documentation |
| `USE_WERROR` | `OFF` | Treat warnings as errors |
| `BUILD_QT6` | `ON` | Build with Qt 6 instead of Qt 5 |
| `OTIO_LOCATION` | - | Path to OpenTimelineIO installation (optional) |
| `OCIO_LOCATION` | - | Path to OpenColorIO installation |
| `OAK_ENABLE_DYNAMIC_RENDER_BACKEND` | `ON` | Build dynamic render backend libraries (`liboakgl.so` / `liboakvulkan.so`) |

---

## Troubleshooting

### Qt 6 Not Found

Ensure Qt 6 is in your PATH and CMake prefix path:

```bash
# Linux / macOS
export PATH="/path/to/qt6/bin:$PATH"
export CMAKE_PREFIX_PATH="/path/to/qt6"

# Windows (MSYS2)
export PATH="/ucrt64/bin:$PATH"
```

### Missing Private Headers

If you see errors about missing Qt private headers, install the corresponding private development package for your distribution (e.g., `qt6-base-private-dev` on Debian/Ubuntu, `qt6-qtbase-private-devel` on Fedora).

### FFmpeg Not Found

Make sure FFmpeg development libraries are installed and `pkg-config` can locate them:

```bash
pkg-config --exists libavcodec && echo "Found" || echo "Not found"
```

### FFmpeg Version Too Old

If you encounter errors like `AV_PIX_FMT_GRAYF16 was not declared in this scope`, your FFmpeg is too old (Oak requires 8.0+). Build from source:

```bash
git clone --branch n8.1.1 --depth 1 https://git.ffmpeg.org/ffmpeg.git ffmpeg-src
cd ffmpeg-src
./configure \
  --prefix="$PWD/../ffmpeg-install" \
  --enable-static \
  --disable-shared \
  --disable-doc \
  --disable-programs \
  --disable-avdevice \
  --disable-network \
  --enable-pic \
  --enable-gpl \
  --enable-version3
make -j$(nproc)
make install
cd ..
```

Then pass `-DFFMPEG_ROOT="$PWD/ffmpeg-install"` to CMake.
