License

DekTec's FFmpeg accesses DekTec devices through CDTAPI, DekTec's open-source C API. Enable it with --enable-libcdtapi. CDTAPI does not require --enable-nonfree, so the resulting FFmpeg build remains redistributable under FFmpeg's normal licensing terms. FFmpeg is LGPL by default; enabling GPL components makes the resulting build GPL, as with any FFmpeg build.

Step 1: Install Dependencies

Compilation on Windows requires Visual Studio. Cygwin, MinGW and cross compilation are not supported.

Install the following dependencies:

• Visual Studio 2022 or newer, with the C++ tools. CMake comes with it.
• MSYS2
• nasm, on the path
• vcpkg, for SDL2

Step 2: Install SDL2

SDL2 is required by ffplay for its display window. Install it through vcpkg:

C:\vcpkg\vcpkg.exe install sdl2:x64-windows

Step 3: Install the MSYS2 Utilities

Launch MSYS2 and install the utilities the build needs:

pacman -S make diffutils pkgconf

Step 4: Build and Install CDTAPI

Open an "x64 Native Tools Command Prompt for VS" and run:

git clone https://github.com/dektec-com/cdtapi.git
cmake -S cdtapi -B cdtapi\build
cmake --build cdtapi\build --config Release
cmake --install cdtapi\build --config Release --prefix C:\cdtapi

Step 5: Build FFmpeg

In PowerShell:

git clone https://github.com/dektec-com/ffmpeg-dektec.git
cd ffmpeg-dektec
tools\dektec\build.ps1 --cdtapi C:\cdtapi --install

The script sets up Visual Studio's x64 tools, as an "x64 Native Tools" prompt does, runs the build in MSYS2's shell, and installs the programs in build\windows\install\bin. tools\dektec\build.ps1 --help lists its options, such as --prefix and --shared.

Step 6: Install the Driver and Run

Install the DekTec driver for your card from the Windows SDK, then list the cards' ports:

ffmpeg -sources dektec

The command-line options page describes what DekTec added to ffmpeg and ffplay.

Alternative: vcpkg

DekTec's vcpkg registry has a port ffmpeg-dektec, which builds CDTAPI and FFmpeg from source in one go. Name the registry in your vcpkg-configuration.json, as its README shows, and ask for the port in vcpkg.json:

{
  "dependencies": [ "ffmpeg-dektec" ]
}