Diễn đàn hỗ trợ Firefox

Some HTML5 videos won't play in my Firefox browser.

This vine for example (https://vine.co/v/b3v5h3Piwt7) only shows up as a static image. I can click the mute/audio button though, but it won't play. When I look at the webconsole when I load the page then 2 javascript warnings show up, the first one say that the Mediasource [long url here] can't be encoded and another one says loading of all candidate sources failed. loading media paused.

I'm using Firefox 21.0 and I tried to run Firefox in safe mode with disabled add-ons, and I also tried to reinstall it, but without success.

Thanks in advance.

I updated to Firefox 35 recently and now HTML5 videos will not work. I do have NoScript, but disabling or removing it does not fix the problem. Switching to safe mode does not fix the problem. The problem is solved by using a fresh profile or deleting the prefs.js file, but this is not an option for me, as restoring all my settings from scratch would be a time-consuming hassle I'd rather not deal with.

I know the problem is with the update to Firefox 35 specifically because everything was working fine before and stopped working after. To be absolutely certain, I turned on my laptop that had the same exact extensions and settings imported to it from this computer with FEBE a while back. It was using version 34.0.5 and everything was fine with that version. I tested it with the Vine website, all videos worked. It also downloaded the update to Firefox 35 in the background and as soon as I restarted it, the HTML5 videos were broken.

It's definitely something Mozilla changed but forgot to alter/remove an old setting that's gumming up the works. If I could just figure out which line(s) in the prefs.js file was causing the issue, I would delete/modify it myself in Notepad.

For the record, I already had media.windows-media-foundation.enabled set to false. All videos that use Flash seem to work. I think Vimeo uses HTML5, but it's the only non-Flash video site I could find that still works. Flash and Java have been updated to the latest versions.

Client said that video cannot load on firefox except other browsers. It shows "Video format or MIME type is not supported". Firefox version is 33.0.3. Video is mp4 format.

I'm running latest Firefox 68.2 64bit on Windows 7x64 Ultimate. This is a new problem, I can plat any media with all my apps and on other sites but Accuweather News https://www.accuweather.com/en/videos/trending-now/co15rob4 videos are suddenly not playable. PS: Firefox Help was useless on this query/error. None of the results were relevant. Am I going to have to "Google Search for the solution? HELP please and thank you.

Videos, like mp4 Vines, won't play in Firefox. Same with the media files like podcasts in rss feeds. All used to work fine. This is an intermittent problem with Firefox ( might be due to updates ) but it doesn't happen with IE or Chrome

If i uninstall VLC player or disable the VLC plugin, nothing happens If i have those installed but the VLC plugin is set to " Never activate ", i can right click on the video image, click " Play " and it opens in VLC player and works perfectly. If i have the plugin set to " always activate " then i see a black square and the message " the video can't be played because the file is corrupt "

Windows 8.1, Firefox 35.

This is an issue with Firefox and needs to be resolved.

Some videos on youtube don't show the 4k resolution option under firefox and the only go up to 1080P but on chrome they show all the resolutions:

example video https://youtu.be/WU-NrfB8Kd4

I have flash installed as well

About a month and a half ago MP4 videos in Twitter 29 played fine. Then I updated to the latest version of Adobe Flash player on both my Win 8.1 and old XP computers. That is when I started getting "This browser does not support video playback" error when trying to play a mp4 video in Twitter. I ran Firefox in Safemode ... no change. I removed all addons ... no change. All Plugins are Ask to Activate or Always Activated. I uninstalled Firefox and Flash player and reinstalled .. no change. The videos work fine in MS IE II and Chrome 53.0.2785.116 m. H264 Codec is installed. YouTube videos play fine.

Every web page with video / audio content begins to autoplay (at the vid's highest volume) approximately 5 seconds after opening the page. I could disable this in Safari and Chromium, but see no option to disable the 'Autoplay' feature in Firefox. Worse, there are no plug-ins or extensions available that will allow this to be done. If you have had success disabling this annoying 'feature' (it's not a 'bug,' right?), please advise how it was done so that I may rid myself of these annoying vids. Thanks in advance.

I have tried to refresh, start in safe mode , reloaded flash and turn on and off, back on of the plug-ins and nothing works to solve problem. I am limited on my knowledge.

Ever since some update, Firefox won't load Vines or Tumblr videos, but load YouTube videos, Facebook videos, and pretty much everything else. I've disabled hardware acceleration, addons, and tried most (if not every) solution given here.

I have installed the 64bit Firefox, removing the prior Firefox program. Now, when I click on a mp4 and choose to open with, browsing to Program Files/Mozilla Firefox/Firefox.exe and clicking does nothing even when set as 'default' opening program. Am I to have the 32 bit installed into program files x86 or is there something else I need to do? Before when Firefox was installed, it was under program files x86, then the change to Quantum, (ran fine, I could use to view mp4 files), a computer crash with 'Cannot repair member file [l:30{15}]"mozilla.browser"', a new install with change folder 'old firefox', removed prior install of Firefox (one with older install date), now have issue that can't use to open mp4 file from computer.

Since ± half october 2018 I can't play videos anymore on some sites and get this crash message. Youtube does work, probably because without Widevine? I'm on FF Dev Edition, Mac with El Capitan. Thanks, Pieter

I have developed a very basic opening page for my web site. It contains a 45 second movie. It works on IE, Chrome, and Safari but will not work on Firefox. Why?

I have spent numerous hours attempting to try workarounds with no luck. I am considering just putting a statement on my front page that says I cannot make this site work properly with Firefox.

It would seem to be in Firefox's best interest to figure this out and fix it vs being the lone browser out there where basic common video formats do not work well.

Please let me know if there is a very quick workaround to make this work because I am certainly not going to spend any more time trying to figure it out.

Thanks for listening

When I click with right mouse button on some facebook videos it doesn't show me options to copy link and etc. It only shows settings for the flash player. how can I fix this?

Happened a few days ago, every time I play a flash video on my Firefox only! chrome and explorer works fine , the image freezes I need to start clicking around and all my icons turn black and it returns to normal and then freezes again, what the hell? this is my favorite browser and I don't want to move to chrome, so please help :(

I am running Windows 7 64 bit and Firefox is my browser. All of a sudden I can not play videos at places like Democracy Now and many other web sites (E.G. Malcolm Gladwell) but most of Youtube is okay - except sometimes. I thought this may have been due adGuard but disengaging it or starting FF clean with no ad ons has no effect.

I was just informed by Costco Concierge Services that the reason is that both FireFox and Google Chrome have decided to “no longer support” certain add ons or plug ins (what is the difference if any between these tech terms of art?) and therefore if I can not play a video I will have to use Internet Explorer. Discovering what videos I can or can not use is a hit an miss case by case basis.

So, first is this true? I can not imagine Firefox or Google Chrome making a change that would actually require its users of many years to bump their prime product and, instead, turn to its prime competitors. That seems like suicidal sabotage. We are just every day end-users and not software engineers and the explanations I find are absolutely incomprehensible technobabble.

In plain English what is the real problem? What is the fix? And has Firefox actually decided to make us dump Firefox and turn to its competitor just to watch certain videos? Has Democracy Now decided to continue using a video format that is no longer supported by FF?

The attached pic is just and example. DN uses jW player but I find this problem at other web sites too.

Today when I started up my laptop, Firefox wouldn't play any YouTube video - the audio still works and the preview of the frame when seeking is there, but instead of video there is just a black screen. I have NO intention of installing Flash Player. Please help? Thanks in advance.

hi is it possible to do so ? i still having high load and memory usage from youtube only videos, i would like to vlc be the default media player in youtube thanks in advance