Firefox Support Forum

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'm running XP on a lap-top that originally had Vista that didn't work as well and Firefox 26.0, up-to date. I have "Add-Ons" of; Adblock Plus 2.4.1, Advanced System Care 1.0 and NoScript 2.6.8.12

Ever since updating to 26.0 that damnable "plug-in container.exe" has been slowing down my web surfing and I'm constantly ending the process in task Manager. I want to disable or remove it completely with easy-to-read instructions - Not some of the 5-page "mumbo-jumbo" I've been reading for other "solutions". It has slowed me down and irritated me to the point of considering returning to I-E.

It has to go or I'm going.

Returning from a four day vacation I tried to load facebook but the error message that the proxy server is refusing connections popped up. I tried to access the help but was unable. I signed off my log on and logged on to my husband and everything works perfect. I accessed help and read other replies and fixes to the same problem. I started in safe mode with no luck, I disabled all add-ons with no luck. I am stumped. I really don't even know what a proxy server is..... please help.

I am trying to open a video file for my online class. When I click on the file, a gray box appears and reads "a plugin is needed to display this content". How do I get my computer to open the video. I have a MAC and zero knowledge of how to fix problems on it.

I am trying different add-ons from your suggestions hoe ever nothing is working. Youtube videos are not playing same as videos and audios from different other sites

Whenever I visit a page that contains even the smallest of Flash objects, Firefox stops responding briefly and then a dialogue pops up to say that Shockwave Flash has crashed. I have tried all of the fixes I have found on other questions: I have reset Firefox, run it in Safe Mode, disabled all extensions, reinstalled both Firefox and Flash, downgraded both Firefox and Flash and turned off Flash's "Protective Mode" etc. The problem only seems to have come about after I upgraded to Firefox 20 yesterday if that is of any help. Flash also crashes on IE and doesn't work properly on Chrome (YouTube does not play sound for example). I have run out of ideas and I was wondering if anyone has anything that I could try. Thanks in advance for any answers!

Example : When I log into my Twitter account, two usernames appear when I type in the first letter of the usename. Firefox does not allow me to delete / remove the unwanted address ...

YouTube works fine. Other websites play videos, no problem. But then I'll go to a website and see a message that the video is either corrupt or is not supported. When I search for how to play mp4 in Firefox I end up at this site: http://www.jwplayer.com/blog/the-state-of-html5-firefox-now-supports-mp4/ With the huge headline Firefox Now Supports MP4. No, it ****ing doesn't! A bit frustrated, because everywhere I look for help on this, I either come across pages saying it should work, Firefox supports mp4 etc, OR forums where it's webmakers asking the question and then the solution is something wrong in their coding - which doesn't help me, the lonely end user. When I go to this suggested test site: http://techslides.com/demos/sample-videos/small.mp4 I get the error message: Video can't be played because the file is corrupt. No, it's not. I can download it and play it on WinAmp. When I go to this suggested test site: http://www.html5videoplayer.net/html5video/mp4-h-264-video-test/ I get the error: No video with supported format and MIME type found. Huh? Again, I can download and play it fine. But Firefox won't play it. Soooooo Is there a fix in the wind? Is there something I can tweak or change to make Firefox recognize and play this stuff? Is there a plugin/extension/addon that I need to download to play mp4? If this is a known problem that is going to be fixed eventually, is there something I can do as a substitute (ie a plugin for now)? Because it seems like the only alternative is to abandon Firefox and start using Chrome, which has no problem with the above-mentioned videos.

Everytime I try to download a "large" file Firefox keeps asking me:

Firefox needs your consent to download large files. Please click ALLOW to continue your transfer.

If you cannot see the request, please click on the icon next to the address bar.

I didn't have this kind of troubles before until the new version, I'm so frustrated that I'm really thinking to switch to Chrome instead.

And in case someone wonders, there isn't a request icon at ALL.

I am unable to play flash video content from facebook or CNN. I am using Firefox 31 and Flash 14.0.0.179 (32 bit) running under Windows 7 Pro. I also have the 64 bit version installed for use with internet explorer. These videos play fine in internet explorer, but not in Firefox. CNN videos stopped playing in Firefox months ago, and Facebook stopped within the last few days.

I started Firefox in safe mode, reset Firefox, uninstalled and reinstalled flash, and uninstalled and reinstalled the latest realplayer (found that suggestion online). So far, nothing has helped.

CNN Videos just freeze once the player control bar appears at the bottom of the frame. The ad plays, but freezes when the actual news video starts.

Facebook shows the thumbnail for the video (will not autoplay like it does in IE) and when you click it you get the pop-up window with the user comments to the right but just a black square where the video should be playing.

If I right click and go to settings for flash, when I click disable hardware acceleration, it re-enables it as soon as I click close on the setting screen. When I go back to settings the box is checked again.

Hi There,

As of today I seem to be having a strange issue with Firefox 31, I'm unsure as to when this problem began as I haven't developed on this project for around 2 weeks. I have a PHP Development server running on localhost port 8000 using the following command: "bin\php -S localhost:8000 -c php.ini" (without quotes)

Upon trying to connect to this server via Firefox I'm presented with "Firefox can't establish a connection to the server at 127.0.0.1:8000." the message adjusts to show "localhost:8000" when connecting via that method, I've tried running Firefox in Safe Mode, reinstalling Firefox and also changing the network settings to "No Proxy" from "Using system proxy settings".

I'm able to connect through Chrome, IE and also by running a cURL command.

Secure Connection Failed SSL received a record with an incorrect Message Authentication Code. (Error code: ssl_error_bad_mac_read)

I have been receiving this error message recently when I tried to access school elearning websites and other school related websites, I have also tried on internet explorer and it shows page cannot be displayed. I have been trying the available solutions to solve it but none of them work. Is there alternative solutions available? Please advise. Thanks.

Morning. Two days ago I reinstalled FF on on clean install of W7. After installing every (software, ext., personas, etc) when I start FF, the "add tab" is sometimes on the far right (which does not bother me), but when I clik on the plus sign, the new tab opens to "Delta Search".

Other times I start FF, and the plus sign is right nest to the tab. And when I click on that Google opens, as it should.

Right now, I'm writing/sending this in Safe Mode. All my software that I have installed, is the same software I have on my XP machine (minus a few things that would not work/or needed anymore).

Any thoughts?

Ran Avast Virus scan. Ran Spybot S7D Ran Malwarebytes Ran all MS tools Online scan ESET

I can provide a screenshot to help illustrate my problem. Every page I load has numerous ad boxes embedded into the page from "Ads by Browse to Save". Does anyone else have this problem? Is this something that firefox added to their browser or do I have a malware problem? (I see no option to post a screenshot of the problem, as is advised on the community help homepage. Maybe I will have that option once my question is posted.)

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Hi, This is the last crash report that I have, it happened a few minutes ago. I've tried usig Firefox in the Safe mode already but nothing seems to solve the problem. Can anyone help me please?

Btw, keep in mind that I'm not British or American please ^^

Firefox suddenly turns totally black while I was browsing yesterday. I tried restarted it, and it works fine. In such state none of the menu or actions items are accessible. Even while closing the browser I get the confirmation popup which is also completely black.

Screenshot link: http://prntscr.com/55kggq

I had to randomly click on the "close tabs" button.

I am using Mozilla Firefox v33.1 in Windows 7, 32 Bit OS with i3 processor, 4GB RAM.

can't move the screen image-display. I hover the mouse-arrow over the edge, to drag the screen inwards and it won't work. Neither the left side, nor the right, nor the top or bottom. I need to be able to do this because my monitor have a graphics error on the far right side of the screen-display that covers about two inches in width the whole length of the right side of my window screen image, so I can not see where to put my mouse cursor in order to scroll up and down. Plus, sometimes I want to make the window image shorter or longer again, and I can't even do that. It seems like it is a "settings" issue. Just don't know how to enable it. Please help.

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.

I have a Windows 8 OS running on a PC. I have been using Firefox as my browser for several months. Suddenly, when I try to load Firefox, I get an error message, "Your Firefox profile cannot be loaded. It may be missing or inaccessible." I have uninstalled and reinstalled Firefox version 21.0 twice, and still get the same error message. How do I get to the profile.ini file using Windows 8, and what am I supposed to do when I ever get there?

So a lot of pages are loading really slow like minutes, like youtube and hot.ee mail service and a lot more. It started to happen when i updated to 20.0. Looked up some suggestions and found that about:config network.http.keep-alive to false help. And so i did it and it worked, but next time i opened firefox again it was slow loading again, but keep-alive is false still, disabled all not nessecary plugins and extensions and i dont seem to find a solution. Been a firefox user for a long time and dont want to change my browser.