Firefox Community Forum

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.

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

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

so i found a strange problem that when i connect headphones to my computer i have a very quiet sound on firefox videos (youtube an ect.). it is not a low volume on my computer or headphones settings, in other browsers everything works smoothly, i dont know why is is only a problem here in firefox

This is a functional bug, not a settings issue. Block media autoplay in Firefox cannot work, after I right-click on a blank area of the page and scroll.

For example, I saw a post with a video on x.com, and the site was set to prohibit automatic video playback. But when I right-clicked on the webpage and then scrolled the page with the mouse, the video started to play automatically, which means that the function of prohibiting video playback was invalid. Very strange.

Firefox version: 141.0.3 (private-browsing No extensions are running) OS: Windows11 Enterprise 26100.4946

I have no idea how to access the following directions I found trying to address the question of : How to stop videos from following as you scroll down a link huff post …..Firefox 135. Mac 12.7.6

Go to about:config and set media.autoplay.enabled.user-gestures-needed to false to disable all kinds of autoplay.

This is where you describe the issue in detail.

Explain what’s happening (e.g., “Videos keep freezing after 10 seconds”).

Mention when it started and what you already tried.

Include your Firefox version (you can find it under Menu → Help → About Firefox).

Audio doesn't work with Firefox. This appears to be ONLY a Firefox problem. Headphones work with Edge. Computer speakers work. In Windows settings, testing audio works. But when I attempt to listen to something in Firefox, there is no sound at all.

I get 'you browser cannot play this video" when I try to watch NFL Sunday Ticket on Youtube; what causes this? I use Linux Mint on my laptop.

I also have Opera browser installed; I get the same error using Opera.

Please help. Thanks.

When i go to fullscreen from default view on YouTube, the screen becomes grey but the video is still playing and the audio is working fine. However, i can go to fullscreen just fine if im in cinema mode. How do i fix this?