Forum communautaire 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?

I have started receiving a secure connection failed error message for a portal log-in website that worked fine for the past 6-7 months (see attached document). Other people in my group use Firefox and Bitdefender to access the portal and none of them are having this issue.

I originally believed the problem to be my anti-virus (Bitdefender) and worked with them to resolve the problems. After trying various solutions including clearing my cache, using private mode and turning off different components of their software, Bitdefender believes the problem is with my browser setting and not their software. I also tried accessing the portal using Chrome in both regular and incognito modes and cannot access the site which would seem to rule out the problem being a Firefox browser problem but contacting Firefox support seems to be the next logical step.

I have been to the Firefox FAQ and saw similar problems with potential solutions - DNS over HTTPS, TLSKEYLOGGING issues, add-on exceptions - none of which worked. I have the most recent version of Firefox and am running Windows 11 home version.

Sometimes if I hit refresh after receiving the error message, the browser will try to connect and I will get a server time out message. If I keep hitting "try again", sometimes the portal log-in screen will appear and allow me to log-in. The key word is "sometimes" since often I just keep getting the server time out message.

Any ideas for me to try from this forum?

I have several saved cards in 152.0.1 (64-bit). When on a payment site the drop-down list shows up as expected, so the extensions.formautofill.creditCards.supportedCountries is correct and working (GB). Also address filling still works, as does saved passwords,

However if I try to "Manage payment methods" the resulting list in "about:preferences#managePayments" is blank. (see image)

I have tried toggling on and off "save & autofill" and restarting, but nothing helps.

Adding a new card works, and the new card appears in the drop-down list on a payment form, but still nothing appears to edit or remove in the settings. How an I edit this list?

PS: I have disabled ALL extensions.

Things like, "set firefox as your default browser" and "open firefox when you start your computer?".

I don't want pop-ups from ANYBODY, but especially not from the browser. It defeats the whole purpose of blocking pop-ups if the browser itself is interrupting me with garbage I dont need.

How do I turn these off? There don't appear to be any settings, and every google search brings up disabling pop-ups for every other site.

Firefox 146.0.1 crashes every time upon launch (basically fails to launch), even in troubleshooting mode, with exception code 0xc0000005. Prior to today, it was working fine. Windows does not show any updates made over the last couple of days. I am on Windows 11 25H2, and I'm current with updates. Chrome works. Edge works. I logged on to the same computer as a different user (different profile folder in the user AppData folder) and Firefox still does not work. I tried to refresh Firefox and that did not resolve the issue. I tried to uninstall and reinstall Firefox and that did not resolve the issue. I tried to run DISM and SCANNOW and that did not resolve the issue. No issues are detected with a virus scan. I am stumped - please help!

I downloaded Firefox today and saw there was a VPN option but it is not working. It asks me to sign in and per the instructions the clickable icon at the top should now have an option to enable but it just asks me to sign in again. I am from Canada and it says my region is available for this program.

In Firefox version 149, there is an issue with print preview behavior for HTML <select> elements. When opening print preview, all <option> items inside a dropdown are displayed and included in the print output.

This behavior differs from Firefox 148, where only the selected option is rendered correctly during print preview.

Steps to reproduce:

- Create an HTML page with a <select> dropdown containing multiple <option> elements. - Select one of the options. - Open print preview (Ctrl + P).

Expected result: Only the selected option should be visible and printed.

Actual result: All options inside the <select> element are displayed and printed.

Impact: This issue breaks the layout of printed documents and makes forms difficult to read, especially when dropdowns contain many options.

Firefox 152.0.3 on Windows 10. SVG icons such as Google Maps interstate shields flash briefly then turn into squiggly lines. Same issue occurs when uploading images to websites and viewing Amazon book previews. Works fine in Chrome. Already tried: disabling hardware acceleration, toggling gfx.webrender.all, gfx.webrender.software.d3d11, gfx.webrender.allow-partial-present-buffer-age in about:config, clearing startup cache, removing Tampermonkey extension, disabling Killer Network Manager (CNMNSST.exe). I uploaded an image of how interstate icons show up in google maps.

Running on Windows 11. There are many supposed "solutions" on the Web, but none of them work. I have tried with: about:config, css files, etc. None of them work.

I like Firefox greatly, but this is so frustrating.

The developers have created a solution to a problem that didn't exist. The result is to make Firefox user clumsy.

It would have been nice if they - at the very least - had provided a way to change the 'Profiles' icon position on the menu.

Again, Firefox 153.0.1 (64-bit) on up-to-date Windows 11. Amd Ryzen 5, 6 core processor, 32 GB Ram, 500 GB SSD C drive = 197 GB free.

I just opened Firefox on my Win 11 pc, and find all my tabs have gone. The setting to reopen last session is active, as before. I think FF updated itself earlier today. I also had occasion to look at it briefly on my synchronised android phone. I would like to: - get my tabs back - find a way to stop this haappening (it's not the first time).

Any advice much appreciated, thanks. Richard

Hi. Now that the 'Open Link in Split View' has annoyingly replaced the spot previously held by 'Open Link in New Window' i keep clicking on it accidentally (muscle memory).

I don't want to have to retrain my muscle memory, but despite creating css file generated by Claude that should in theory remove the option, and putting it the Profile Folder, it will not go away.

How do i remove it?

I went to [https://support.mozilla.org/en-US/kb/firefox-backup] and under "Create a Firefox backup file" at step 3 it says, "Scroll down to Backup, and click Manage backup" but when I went there no such "Manage backup" option exists as you can see in the attached screen capture. So what gives? How can I "Create a Firefox backup file"? I am using Firefox v147.0 (64-bit) on Windows 11 Please instruct. Thanks RJB

I read the article about having 50 GB of free VPN use after I updated Firefox today to version 149.0; however, I don't see anywhere where I can enable the VPN. I've checked in the "Customize Toolbar" section, and I still couldn't find anything. I don't understand, the article made it sound like I should have access, but I've also read that it's not out for everyone yet?

Since recently 1~2 version, my Firefox keeps consume large amount of memory and release it repeatedly

Even I restart Firefox and do nothing, it will start doing this again

I use about:processes and about:memory to capture this seems the main process's "tab.query" causing this, please check

PS: sometime it will consume till system max (64GB) and cause my OS out of memory. PS2: that wave-like memory usage is cause by Firefox

I am reopening the question from 2020 as the solution described no longer seems to apply. https://support.mozilla.org/en-US/questions/1284577

I am running Windows 11. Firefox 144.0 (64-bit)

When entering search terms into the search bar in the centre of the page, the information typed appears in the address bar, even after following the fix described in 1284577.

Treating the address bar as the search bar appears to be the default. While the user can additionally deselect the search engine in the address bar, that is an unnecessary and undesired additional step for every search (the primary reason I am using Firefox)

Is there a way to permanently set the default for what I enter into the search bar to remain in the search bar and not to be managed by the address bar? Thanks, Rich

I have read all your tutorials. I was unable to have an important televisit with my doctor yesterday because nothing I tried worked. I am unable to use webcam for other sites until I resolve this problem. Previously I had no problem with my webcam but recently had to get new pc with windows 11 & needs to configure my pc to address this issue. I have another appt scheduled with another doctor & need to fix this problem asap Thanks

I am using FF Private browser for sensitive pages that I don't want tracked by my add-ons. However, a major annoyance is how stored passwords seem to be handled. E.g., when I try to login, and say I have 3 stored logins (all for the same URL), then FF private only offers one of them (chosen at random it seems), hiding the 2 others. Why does it do that? It just seems monumentally stupid and is a major usability hindrance. Tracking protection OK, but if this is the result then why bother. It makes the browser unusable.