Firefox Community Forum

Earlier today the audio on Firefox stopped working. I have tried disabling extensions, checked output devices, reinstalled and it still doesn't work. Please Help. The Version is 150.0.1

Media resource could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_DECODE_ERR (0x806e0004) Details: virtual mozilla::MediaResult mozilla::FFmpegVideoDecoder<62>::DoDecode(mozilla::MediaRawData*, uint8_t*, int, bool*, mozilla::MediaDataDecoder::DecodedData&): avcodec_send_packet error: Unknown error occurred

(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?

Trouble with streaming services(like youtube(only streams ), twitch, music streaming) on nightly Firefox Nightly 145.0a1 (2025-10-11) (x64) Cachy OS Binary from firefox.com

no matter what I try I cannot get any content from HBO max, crunchyroll, or spotify to play. I feel as though I have tried every troublshooting step. In firefox 140.0.4 64 bit on windows 10 I have:

-turned DRM off and on -disabled and re-enabled widevine -disabling all extensions -try in a private tab -turning off tracking protection -clearing cookies/cache/site data -uninstalling and reinstalling firefox -trying on firefox nightly -trying on other firefox based browsers zen, librefox same issue. chromium based browsers and firefox on my windows 11 laptop play drm content like normal -manually installing older version of widevine -changing useragent to chrome(this triggered cloudflare and would not let me pass) -making another user in windows and trying there

the error i get on crunchyroll is code: DRM-0 and on spotify it loads but the play icon does nothing. in hbo max i get error code 1k-0003

At this point I don't know what else to try, If there is not another solution I probably try to just switch to brave browser or wiping this pc and reinstalling windows.

So, my problem is with HW acceleration in FF. Basically:

If its enabled: It causes graphical artifacts in videos [See screenshot]. If its disabled: It brings screen tear in to videos and autoscroll [Like if Vsync is disabled in games].

I tried safe mode, I tried reinstall of FF, I tried disabling and enabling extensions. I tried to set Vsync on in Nvidia control panel... the only thing that impact those bugs is HW acceleration in FF.

My drivers are up to date, my browser is up to date, yet there is such trouble.

Any ideas or solutions?

hi for some reason twitch.tv or some other websites will no longer play videos on my pc and i have no idea why, firefox works fine on my laptop

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.

Здравствуйте. При воспроизведении видео на каком либо сайте в полноэкранном виде не скрывается панель задач виндовс. На других браузерах работает как надо. Менял где только можно, даже в безопасном режиме также. Как её можно убрать?

I'm running the latest version of Firefox on the latest version of Windows 11, and I'm trying to watch TV shows on PBS's Passport service. I get the video but not the sound. It's been like this since Saturday. I don't have this problem at all with Chrome or Edge. Is anyone else having this problem? JT

I think everyone knows how to get out of full screen mode by now, so can you either remove it or let us disable that little box that always shows when you go full screen for a video?

I've freshly reinstalled Windows 11 and after trying to access and watch a movie on any of these sites I get an error (see the pictures).

Browser version: 137.0.1 (64 bit) Widevine version: 4.10.2891.0

Already tried to disable/enable DRM. Already reinstalled firefox. Already manually installed widevine. No clue what could be causing this issue.

I am using Pop OS. Videos are not playing in firefox. In youtube it shows loading infinitly. In reddit all videos become green. I tried playing a downloaded video it also become green. These are only happening in integrated mode. If I use hybrid graphics mode all works good. I attached the about:support page and about:config page.

about:config page link about:support page

These files are taken in integrated graphics mode.

This is the link to the video that will not play in FireFox. https://www.swingtechnologies.com/UploadVideos/clarkj@pobox.com/S200629_019 B.mp4

Hi,

How can I force Nightly to play a media type ? Per instance, the top main video here : https://www.lapresse.ca/international/asie-et-oceanie/2025-12-23/coree-du-nord/kim-jong-un-inaugure-un-complexe-hotelier-dans-une-station-de-montagne.php

Best regards iBenny