Forum der Gemeinschaft Firefox

Since Flathub list the org.mozilla.firefox app as official, i hope this is the correct support channel.

Recently i switched from distro specific package managers to flatpak as my application provider. The firefox flatpak won't play most embedded Video/Media on applications like in-browser fediverse clients, forums, blogs or wikis. Youtube works without any issues, Twitch is fine until there is an adbreak. Then it sometimes stops with the supported format/mime error (screenshot appended), only recoverable by cache-dismissive reload.

I used this Article https://support.mozilla.org/en-US/kb/audio-and-video-firefox and the links it contains to debug without any success. None of these samples play. just shows supported format/mime error https://test-videos.co.uk/bigbuckbunny/mp4-h265 At this test website 1. and 3. example won't play. I provided a screenshot before and after trying to click play on all the examples. https://www.tekeye.uk/html/html5-video-test-page

Contrary to the observed behavior about:support#media claims Software Decoding supported for everything except HEVC.

Chromium Flatpak has no such issues. So i copy the video url and play it with chromium. You can see: dire times.

Specifically Youtube videos, Youtube music songs and nothing else either never load (95% of the time), load only the first 10 seconds and then buffer or load partially after ~20 minutes. No error messages. Only in Firefox.

I tried: Reinstalling Firefox Switching profiles Disabling all extensions Running in safe mode Clearing site's cache and cookies

It's been like this for a couple of months. Been circumventing it by playing videos in a different browser, but would be nice if there was a fix.

Attached image with a loading screen (lol).

It's a repost btw, posted 2 weeks ago and got 0 views.

I have noticed recently that when i try to play certain videos i am sent that are embedded on webpages the screen just goes black and i cannot see anything but i can still hear the video playing in the background. Why is this happening. I have a new HP envy laptop and am using firefox browser but when i use my work laptop which does not have firefox (IBM Thinkpad) i do not face this issue therefore i assume it is a setting in firefox

Trying to run Prime and Netflix in a Linux browser on my new Lenovo Chromebook Plus 14. Not that this is an ARM based unit (Kompanio Ultra 910).

I can successfully download Firefox for Linux: Mozilla Firefox Debian Package mozilla-deb-1.0 144.0 (aarch64)

But when I go to run streaming video services get: Prime Video is incompatible with your current operating system or web browser. You must update to watch Prime Video titles. Review the Prime Video system requirements. If the problem continues, please contact Amazon Customer Service and refer to error 7132.

Same with Netflix.

any ideas, thoughts, solutions?  :)

Cheers.

As the title says. I get this prompt on videos from different, yet particular websites and sources. And they fail to load. It's also happened where some video's work and some don't, side-by-side on the same website and session.

• I've tried clearing all of my cached data, my browser history, cookies, site-data, settings, and fill-out information. No avail.
• I've tried disabling all of my extensions and add-ons.
• I've even tried using google instead, but I just get constant loading on those particular video's with no thumbnail (As depicted in second picture).
• I've checked my video drivers for updates.
• I've tried reinstalling Adobe Flash Player, even though it says it's no longer supported.

Since it also might be happening in another browser. I understand how this might not be Firefox's fault. But I'm hoping you'll be able to help me still.

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.

Only on firefox, the music on apple music keeps changing volume. I can hear it sound fine for a second but then it changes the volume to around half of what its meant to be. I dont see any settings to change it, its fine on other browsers, im genuinely unsure of what to do.

Whenever I play videos on YouTube in Firefox, the video is always choppy and does not run smoothly. I’ve tried restarting the browser and checking my internet connection, but the issue continues. This problem only happens in Firefox, not in other browsers.

I just switched to a new PC (Windows 11) and when using Firefox to watch videos, the audio fades in briefly instead of starting instantly. This happens with youtube, prime video, netflix etc. I have tested in Edge and this does not occur. I am using a bluetooth headset. I haven't been able to find anything about this online so open to any help.

So Im currently trying to watch young sheldon on netflix, and im doing it through firefox, and it wont work, it says error code f7701-1003, thank you for your time.

For the last two years the issues with video stutter have been worse and worse for me. I don't know if it is because of a different codec the video is using, but if it was I would expect the fans to ramp up from trying to decode it. Instead, my laptop stays always silent, but the video laggs like crazy when I want to play it at native 1440p.

I cannot view or change the video codec, since the current issue happens on a platform (herohero.com) other than youtube.

Hello. On/about 25jun2025 the sound on my Firefox videos stopped working from any source. I know enough to determine the problem is on Firefox. Videos on MS Edge worked fine. Sound works form VLC songs, etc. Sound does work with earplugs. Wondering if that could have caused the loss of speaker sounds. You think I could delete my current firefox and reinstall it. That would be a pain (an hour or so to set it up again.) Thanks, Bill

Hello Team, I am having issues with Mozilla Firefox and Nightly Browser sound. If I use another browser, the sound is perfect. I have been using Firefox for years now and am accustomed to it, as well as Nighty, for all browsing needs.

Regards, Roopesh

Hi,

I have been having this weird issue that I believe is being caused by firefox as no other internet browser has the same issue. When I'm playing music on spotify and I open firefox the sound goes quite bu the audio is still playing on spotify . One work around I have found is to take on of the tabs and use it to open a new window and the put it back with the others and the sound comes back again. I lost and need help as this is making it hard to want to use firefox which I have been a user of since it first came out.