Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

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 video not supported in FF 65.

  • 1 reply
  • 1 has this problem
  • 6 views
  • Last reply by James

more options

My MP4 video is not supported in FF 65. But this is supported in lower versions.

My MP4 video is not supported in FF 65. But this is supported in lower versions.

All Replies (1)

more options

The videos may be playing in a HTML5 player.

One type of package Linux users may not install after OS install is FFmpeg due to restrictions and it may vary in package name depending on Linux distro. Firefox has not used Gstreamer for a long time now since Firefox 46.0 and later. Bug#1234092. However some Linux distros may still use Gstreamer for their third-party builds for a while after, not sure about the third-party Fx 56.0 you have though.

You can test at https://www.youtube.com/html5 where if a couple check marks are red then you maybe missing the FFmpeg.

The Ubuntu restricted extras is a way to install FFmpeg if using Ubuntu or a flavor of Ubuntu

Modified by James