Firefox Community Forum

Hi,

Audio is not working in my firefox browser. i am using Windows 10 laptop. tried all troubleshooting options, uninstalled and reinstalled firefox application . But the issue exists. Can anyone help to fix this audio issue in my browser?

(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?

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Hi,

The Firefox browser came through with an update and I found that on Bluesky it is hard to load or see video's, which makes it a slightly pointless exercise.

Previously I have found that after an update (can't recall if it was Chrome, but think it was Firefox) the problems cleared up after a couple of days.

However, that doesn't seem to be happening right now.

Can't think what I should be tweaking at my end.

Whenever I try to full screen in any streaming websites, it's not full screen at all. There is a little bit of space in the left-side and top-side of the screen where the other windows or applications I have can be seen (or my desktop if nothing else is open). This is not happening to other browsers. Can you please help me to fix this?

For the last maybe 2 weeks of so I have been able to play videos on any website,it is only Firefox that is having the errors. I use Windows 10, and the only extension I have is password managment

I have tried: 1) troubleshoot mode: no changes 2) clearing cache: no change 3) making a new Mozilla profile: no change 4) lowering/turning off security protections 5) refreshing from uninstall 6) uninstalling and reinstalling 7) Allowed autoplay of media 8) toggled off drm

The primary sites that I use are; HBO - error 1K-003 Twitch- error#4000 Patreon- doesn't error out, but just goes black on player Dropout.tv- player error YoutubeLive- Browser error

When I watch Downton Abbey on PBS from outside the U.S, using the Firefox VPN in a Private Window the Closed Captions of the PBS video are displayed TWICE: one above the timeline and the other above it.

This issue is specific to this particular show AND to the Firefox browser.