I tried to enable libass for ffmpeg with this --enable-libass in command but it didn't recognise the command.

Does anyone know how to enable libass on Linux?

  • what version of linux? It is possible libass is not installed on your system.
    – Ketan
    Commented Feb 20, 2014 at 4:59
  • 2.6.32-358.2.1.el6.i686
    – cea
    Commented Feb 20, 2014 at 5:08
  • What distro is what we should've asked.
    – slm
    Commented Feb 20, 2014 at 5:09
  • i386 GNU/Linux if that is what you mean.
    – cea
    Commented Feb 20, 2014 at 5:16
  • cea: please run the command "cat /etc/issue" on your terminal and show its output here. Commented Feb 20, 2014 at 6:30

3 Answers 3


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:

  • It says nothing to do when tried simple yum install so that means it must be installed? I did download the static build.
    – cea
    Commented Feb 20, 2014 at 5:09
  • @cea - yes, you can confirm with this command too: rpm -aq libass.
    – slm
    Commented Feb 20, 2014 at 5:10
  • Thank you, it says libass-0.10.0-3.el6.i686 so I wonder why I am getting font config not found in output. That is the reason I'm trying to enable.
    – cea
    Commented Feb 20, 2014 at 5:14
  • @cea - see this FFmpeg ticket: trac.ffmpeg.org/ticket/1688
    – slm
    Commented Feb 20, 2014 at 5:18
  • ok thank you, no-one was ever able to give him an answer "closed defect (invalid)" what ever that means, anyway I will have a think on it.
    – cea
    Commented Feb 20, 2014 at 6:24

recompile ffmpeg with:

./configure --enable-libass


sudo make install

Then check the new ffmpeg without arguments:


Mine says "libass" is in the new config.

Then, to convert videos I use:

ffmpeg -i input.avi -vf "ass=subs.ass" out.avi

To obtain the subtitles in .ass from .srt I use:

ffmpeg -i subs.srt subs.ass

Good luck!

  • Upvoted. Could you also add details on downloading the installation files, opening a terminal, cd to folder and then issuing the ./configure. Also explains that apt is being bypassed in order to get the latest greatest. Might be obvious for you but not for noobs. Also, we want to get more people in Linux
    – Tarik
    Commented Dec 13, 2020 at 8:04

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