Firefox Community Forum

Windows 11 Pro - Dell XPS8940 desktop - i9

Firefox will not play video from a website. If I save the video, it is a MP4 file. Windows Media Player and VLC will play the video file. But the browser shows the message: "No video with supported format and MIME type found."

Chrome and Edge will play this video correctly in their browsers. Firefox will not play the video on 3 different computers, and even when a different user account is involved (without Firefox sync).

The evidence seems to point at firefox. The website is a Wordpress site.

Is it possible that the website is the problem? If so, why do Edge and Chrome work?

I uninstalled Firefox (latest version) and reinstalled it. Not fixed.

My windows updates are current, as are Dell updates.

This is stumping me. I hope someone can help.

I used the CSS animation property called animation-timeline , which is written as:

element{ animation-time: view(); }

When I view the webpage on Chrome, Edge, Opera, and even on Phoenix browser, the animation works.

It is only on Firefox that the animation does not work. I even added the Vendor-prefix of " -moz-animation-timeline " to the CSS property, and it still didn't work on Firefox, while it is working on all other browsers.

The CAN I USE website ( https://caniuse.com/?search=animation-timeline ) tells me that Firefox does not support it at all.

It however said that I can enable it, by setting "layout.css.scroll-driven-animations.enabled" to true.

1.) I don't know what that means.

2.) Would my website's users be able to see the animation on their Firefox browser, if we assume that I make this setting ?

3.) I am using Firefox version 138.0.3 (64-bit) : What can I do to see that both I and users of my website are able to see this animation on Firefox ?

Regards.

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