Suddenly, the video stopped working.
The first frame flashes, then a black screen and a message.

it should be updated for play video

Ubuntu 14.04, Firefox 50.0

dpkg -l | grep libavcodec ii libavcodec-extra 6:9.18-0ubuntu0.14.04.1 all Libav codec library (additional codecs meta-package) ii libavcodec-extra-54:amd64 6:9.18-0ubuntu0.14.04.1 amd64 Libav codec library (additional codecs) rc libavcodec53:amd64 4:0.8.16-0ubuntu0.12.04.1 amd64 Libav codec library rc libavcodec54:amd64 6:9.18-0ubuntu0.14.04.1 amd64 Libav codec library

    1 answer 1

    I found a workaround.
    I hope someone here will offer a better solution.

    Obviously, the problem has appeared recently and is related to updating Firefox.
    A Google search led me to Super User .
    The accepted answer suggests

     sudo add-apt-repository ppa:heyarje/libav-11 sudo apt-get update sudo apt-get install libav-tools

    and then

     sudo apt-get upgrade

    I did, and then another

     sudo apt-get update

    But it did not help :(

    Then I told Firefox to use the old libavcodev, as suggested by another answer to the same question.

    • We write about:config in the address bar,

    • agree to take responsibility

    • and change media.libavcodec.allow-obsolete to true .

    Firefox now shows video, but it has become less secure.

    Upd: The version of Firefox 51.0.1 has brought everything back. It seems everything works.