Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

MP4 videos won't play on firefox on ubuntu

  • 4 replies
  • 1 has this problem
  • 2 views
  • Last reply by cor-el

more options

The videos work on microsoft edge, vlc, mplayer, mediaplayer ... but Firefox informs that they can't be played because they are broken. mp4 playback is activated and https://www.youtube.com/html5 informs that h 264 (which is the codec used on the videos) is supposedly available on my browser. Yet none of them work.

The videos work on microsoft edge, vlc, mplayer, mediaplayer ... but Firefox informs that they can't be played because they are broken. mp4 playback is activated and https://www.youtube.com/html5 informs that h 264 (which is the codec used on the videos) is supposedly available on my browser. Yet none of them work.

All Replies (4)

more options

If you can fully support HTML5 player for video and audio then all check marks should be blue on https://www.youtube.com/html5

Firefox has not used Gstreamer for several releases now as FFmpeg and libavcodec is used. You need at least libavcodec 54.35.1 version or later as older versions are blocked starting Firefox 50.0 and later.

Modified by James

more options

All marks are blue on https://www.youtube.com/html5

Libavcodec is 56.60.1

The files work on all the other browsers / players that I have tried

Firefox is unable to open any of them

more options

All marks are blue, Libavcodec is updated, still none of the mp4 videos work.

more options

What error messages do you see in the Web Console ("3-bar" menu button or Tools -> Web Developer)?

Does it help if you enable webm? about:config: media.*enable

Try the Firefox version from the official Mozilla server if you currently use a version from the repositories of your Linux distribution.