Komunitné fórum Firefox

(AI written summary of troubleshooting steps taken before making this support thread)

Firefox version: - 152.0.1 Release - 153.0 Nightly

OS: - Windows 11 build 26200

GPU: - NVIDIA GeForce RTX 4070 SUPER

Codec package: - Microsoft HEVC Video Extensions installed from Microsoft Store

Problem

Firefox does not expose HEVC playback support, causing Twitch to disable 1440p streams encoded with HEVC.

The same machine can play the same HEVC Twitch streams in Chrome immediately after installing HEVC Video Extensions.

Expected result

Firefox should report HEVC playback support and allow playback of HEVC streams, as Chrome does on the same system.

Actual result

Firefox reports HEVC as unsupported.

about:support:

codecSupportInfo: H264 SWDEC HWDEC VP9 SWDEC HWDEC VP8 SWDEC HWDEC AV1 SWDEC HWDEC HEVC NONE

Troubleshooting already performed

- Installed Microsoft HEVC Video Extensions - Rebooted Windows - Updated NVIDIA drivers - Verified hardware acceleration is enabled - Tested with a brand new Firefox profile - Tested with Firefox Nightly - Confirmed Chrome can play the same HEVC streams

Additional observations

Chrome: - Twitch 1440p becomes available immediately after installing HEVC Video Extensions - Twitch Stats for Nerds reports:

 hev1.1.6.L150.90.0.0.0.0.0

Firefox: - Twitch reports that the browser does not support the required resolution - 1440p remains greyed out - about:support continues to report HEVC NONE

Reproducible tests

Firefox console:

MediaSource.isTypeSupported('video/mp4; codecs="hev1.1.6.L150.90"')

Result: false

MediaSource.isTypeSupported('video/mp4; codecs="hvc1.1.6.L150.90"')

Result: false

navigator.mediaCapabilities.decodingInfo({

 type: "media-source",
 video: {
   contentType: 'video/mp4; codecs="hev1.1.6.L150.90"',
   width: 2560,
   height: 1440,
   bitrate: 8000000,
   framerate: 60
 }

})

Result: {

 supported: false,
 smooth: false,
 powerEfficient: false

}

For comparison:

MediaSource.isTypeSupported('video/mp4; codecs="av01.0.08M.08"')

Result: true

navigator.mediaCapabilities.decodingInfo({

 type: "file",
 video: {
   contentType: 'video/mp4; codecs="av01.0.08M.08"',
   width: 2560,
   height: 1440,
   bitrate: 8000000,
   framerate: 60
 }

})

Result: {

 supported: true,
 smooth: true,
 powerEfficient: true

}

Additional note

Setting:

dom.media.webcodecs.h265.enabled = true

causes HTML5 codec test (https://html5test.co/) to report H.265 support, but does not change:

- about:support - MediaSource.isTypeSupported() - MediaCapabilities.decodingInfo() - Twitch HEVC playback availability

Question

Is this a known issue with HEVC Media Source Extensions support on Windows 11 build 26200, or is there another requirement for Firefox to expose HEVC playback capability through MediaSource and MediaCapabilities when the Windows HEVC codec is installed and functioning in Chromium-based browsers?

So I clicked into a video, and it did not play. Further troubleshooting showed it was a video hosted by vimeo, and youtube videos still worked. I tried on multiple vimeo hosted videos, on multiple unconnected websites (dropout, patreon, and directly on the vimeo website).

I tried the following fixes:

• I opened it in a private window and nothing played.
• I booted into safe mode, still nothing.
• I turned off all of my add-ons, nope.
• I cleared my cache and restarted, nothing.
• I cleared my browsing data and restarted, also nothing.
• I checked for updates: up to date.
• I created a test profile, and it works there.
• I opened Chrome and it worked there too.

The test profile/chrome thing suggests it's an add-on or something but the fact that I turned them all off and this still happened has me baffled.

Update: I fixed it. Was user error.

No audio on Firefox. Google Chrome has sound. Settings at normal audio volumes. Tried computer shut off and re-boot. Tried reload of Firebox.but that didn't help. Had scam attempt just before no audio issue...not sure if that problem.

Hello, I am currently using windows 11 with firefox 149.0. Regardless of what website I use (youtube. steam etc), the browser struggles to establish consistent connection to my bluetooth earbuds. It connects for one moment, but then soon the volume goes out and eventually it disconnects. Though it would reconnect soon, the cycle just keeps ongoing. I have experimented with other apps and browsers, as well as multiple bluetooth earbuds of other brands to be sure that it is a firefox issue. I have checked the volume mixer menu to ensure that there is nothing wrong. I have also made sure that my drivers are all up to date with no issue. But the issue still persists.

There is an issue with MKV video playback with MP3 audio track in FireFox. The problem is that MKV video plays MP3 audio track without any sound. With AAC audio track the problem is that MKV video initially downloads whole video and only then plays it. In comparison with MP3 and AAC the benefit of MP3 is much better quality and it starts playing without downloading whole video like MP4.

It would be nice if you add support MKV video with MP3 audio playback.

Video file link: https://v01d.have.lv/vp/movies/test/fm/al.mkv

Browsing this website article I can see that there are embedded Youtube videos in the article but they are not loading, instead I only see blank spaces. I've turned off all extensions, turned off tracking protection, cleared cache and cookies for both the website and Youtube.com, and tried viewing the website in troubleshoot mode.

Facebook videos in Firefox stop playing when clicking the Windows 11 Start button or opening Solitaire (after recent update)

This issue has just started after a Windows 11 update and restart. It has never happened before. I usually watch Facebook Reels while playing Solitaire at the same time — yes, I know, I don’t have a life.

This morning, after the update and restart, I opened Facebook and started watching a Reel as normal. As soon as I clicked the Windows Start button to open the list of programs, the video stopped. I then selected Solitaire, which opened to the taskbar. I restarted the video, clicked Solitaire to open the game fully, and the video stopped again. As soon as I minimize Solitaire, the video resumes playing.

I’ve tried all the suggestions I could find via Google, but nothing has worked so far. Note that this only affects videos playing directly on Facebook — videos playing in the Windows Media Player Legacy video player itself are not affected.

Any help would be greatly appreciated… and yes, as mentioned, I clearly don’t have a life 😅 Link to video showing what happens when I select Solitaire in the Taskbar. https://drive.google.com/file/d/1oKLIl3I4f9lfTZvbU-9pJ1gMbOU7h0zm/view?usp=sharing

Regards everyone.

More info... I run two monitors and it seem if I click on whatever I have open in the second monitor the FB video stops. So something has changed after I turned my computer on this morning and updated Windows. I even did a System Restore to a setting two days before this new update and nothing changed still have the problem.

When I play YouTube videos in Firefox, the video stutters and drops frames, even when set to 480p. The audio continues to play normally. This issue does not happen in Chrome on the same laptop.

The problem started about a week ago. I’m using Firefox on Windows 11. Restarting Firefox did not resolve the issue. I’ve attached screenshots for reference.

I swear this used to be a setting and it vanished or i'm blind. say you open a youtube video in a new tab while staying on your current browsing tab, it used to auto-pause in the background until you navigate to the new tab. I remember being so happy when i found the setting, and it stopped working recently so i went looking for it. it doesn't exist. send help.

Hello, I am facing an issue while playing YouTube videos in Firefox. The videos are lagging and not playing smoothly, even though my internet connection is fine. Please help me fix this problem.

Just built a new PC and using Win11. I like to have a pinned tab in Firefox playing some kind of media to have background noise. Since new build, whenever I am not 'focused' on that tab and doing other tasks, audio from that tab will cut/fade in and out.

I've been working on this for 16 hours. I've googled, binged, even yahooed. No answers. Checked and rechecked all settings, both system and browser. Uninstalled/Reinstalled *many* applications, including Firefox. My OCD won't let me rest till I have this solved.

Thanks for the help.