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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

I just upgraded Firefox to version 156.0.2.

It no longer plays mp4 content from a website. It says "No video with supported format and mime type found".

This used to be OK.

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.

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.

When I open Facebook in Firefox 150.0.1 with no extensions then move the cursor over a video, that video automatically plays.

Preferences | Privacy and Security | Browser Privacy | Permissions | Autoplay | Default is set to Block Audio and Video yet videos still automatically play.

Since the last update, I believe, because this error occurs constantly and with EVERY video. This is often, not always, the case immediately after updating FF. Now it was fine for a while, but now it's so bad that I'm having trouble watching YT videos properly. Reason: Browser open, logged in to YT. I click on a video to play - video opens, plays maybe 10 to 20 seconds, then playback stops spinning top, I also found out during the last glitch after update that if I switch the resolution briefly, higher or lower doesn't matter - important is to leave the current resolution and switch to another one. And oh wonder - immediately, instantly with the change, the video starts playing. If I wait for this - without doing anything myself, it sometimes takes 30 - 40 seconds for the video to start ... sometimes it just "hangs" ... This is extremely annoying - if it doesn't work, I have to switch browsers... What is also extremely annoying is that it occurs almost regularly after an update ... until the next one possibly, for unknown reasons, does not fix the error, but sometimes mitigates it. Now, however, the disruption/interruption is so massive and totally annoying that I'm thinking of switching. I'm just tired of it ...

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Since the last update, I believe, because this error occurs constantly and with EVERY video. This is often, not always, the case immediately after updating FF. it was fine for a while, but now it's so bad that I'm having trouble watching YT videos properly. Reason: Browser open, logged in to YT. I click on a video to play - video opens, plays maybe 10 to 20 seconds, then playback stops spinning gyro, I also found out during the last glitch after update that if I switch the resolution briefly, higher or lower doesn't matter - important is to leave the current resolution and switch to another one. And oh wonder - immediately, instantly with the change, the video starts playing (for a while at least maybe 5 Minutes maybe 30 Sek... i´m done with FireFox ...) If I wait for this - without doing anything myself, it sometimes takes 30 - 40 seconds for the video to start ... sometimes it just “hangs” ... This is extremely annoying - if it doesn't work, I have to switch browsers... What also bothers me extremely is that it occurs almost regularly after an update ... until the next one possibly, for unknown reasons, does not fix the error, but sometimes mitigates it. Now, however, the disruption/interruption is so massive and totally annoying that I'm thinking of changing. I'm just tired of it ... Please fix it or shoot me ... any suggestions ??

Hello! from this morning and alongside a new Firefox update i've been having graphical artifacts on Youtube/Facebook/Netflix. I've followed all the standard steps.

Disabled Hardware Acceleration. Updated Video Drives. Run FF in Safe Mode without plugins. Disabled Router level VPN and Ghostery.

Any ideas?

I'm running FF135.0 Geforce 572.16 Drives (30th Jan) 3070TI. Windows 10 Pro 22H2.

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.

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

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.

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

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

I couldn't sign my Alejandra .com on my computer so i need to cahnge to Firefox aboutpreferences@tabsBrwosing so the video from Aljazeera video live news awork on my computer Thank kind regards Peter tan

After updating firefox from 128.8.0 to 128.9.0, no embedded videos will play (youtube, instagram, plex, etc...)

The only way to get them to play is to run the browser in troubleshoot mode. Even a fresh browser profile doesn't work. Disabling hardware acceleration also does not work. Tried firefox 137.0.2 and that also does not work. Downgraded back to 128.8.0 and videos play flawlessly again.

I'm running firefox on gentoo linux on a thinkpad x13s (arm64) which uses Qualcomm Adreno 690 graphics.

Anything I should try would be greatly appreciated. Thanks.