RTDXT Setup - CESNET/UltraGrid GitHub Wiki
In order to use GPU-accelerated DXT compression, you need to have your graphic card's drivers installed and your X started.
Install these packages:
apt-get install mesa-common-dev libx11 libglew1.5-dev # Ubuntu, Debian
zypper install glew-devel Mesa-devel # openSUSE
yum install mesa-libGL-devel glew-devel libX11-devel # Fedora, CentOS
A card and software supporting OpenGL 3 or higher is required.
Once the required packages are installed, this feature compiles automatically with UltraGrid.