How to enable libass on Linux?

On Ubuntu or Mint:

sudo apt-get install libass-dev

First you need to make sure that your particular version of ffmpeg was built with and supports that switch. You'll also likely need to make sure that the library libass is installed as well.

You don't specify your Linux distro but I did notice that libass is available in my stock Fedora 19 repository so it's trivial to install.

$ sudo yum install libass

Now back to ffmpeg's support of libass. You can confirm how it was built by simply running it without any arguments.

$ ~/ffmpeg |& grep libass configuration: --prefix=/root/ffmpeg-static/64bit --extra-cflags='-I/root/ffmpeg-static/64bit/include -static' --extra-ldflags='-L/root/ffmpeg-static/64bit/lib -static' --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared --disable-ffserver --disable-doc --enable-bzlib --enable-zlib --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3 --enable-libvpx

So the version that I have, does include this support, --enable-libass. If your version of ffmpeg doesn't support it you can simply download a static build:

• https://johnvansickle.com/ffmpeg/