You can try to set the media.windows-media-foundation.enabled pref to false on the about:config page to disable the built-in mp4 media player.

• http://kb.mozillazine.org/about:config

The about:config change did not work for me. Many vines (but not all!) don't play. Firefox 22. Latest Flash (if that matters). Tried on Windows 8, Windows 7 and Windows XP! (3 different computers, 2 different networks).

Here's another one that fails: https://vine.co/v/huHUPLnx1dg

Grabbing one at random from vine roulette--here's one that works fine:

https://twitter.com/marion_okuyama/statuses/360692023075938305

What's the difference???

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can also check the cookie settings.

Clear the cache and the cookies from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > Cookies: "Show Cookies"

Thanks. Tried safe mode--it worked! Once! Went out of safe mode and it didn't work. Clear cache, went back into safe mode--and it STILL didn't work. Weird. Now, nothing--no combination of safe mode, deleting history (including cookies) fixes it. Even finally reset my settings my firefox settings to default. No go.

A good test site for the issue is microsoft's "The browser you love to hate" site. It has about 7 vines half way down. One ALWAYS works. The rest, never work. http://www.browseryoulovedtohate.com/

What is up with this. As I said before, this occurs on multiple computers, Win 7, Win 8, XP. Different networks.

My big question is--Am I the only one seeing it? You guys are fine on those sites with the Vines? And if so--are you running Windows?

Does it work in a Private Browsing mode window?

No, same behavior in Private Browsing.

I can clear cookies on the page or force it to ask to set cookies or only allow during the session. That--combined with clearing the history and restarting Firefox -sometimes- seems to work--but without changing a thing, trying the site again fails once more--even when doing the same steps.

Going crazy! Since it happens on my other computers too--I'd appreciate a response on one thing: Can you go to: www.browseryoulovedtohate.com and see ALL the Vines (they are about midway down the page) with no problem? And--if you then close Firefox, and go back, can you STILL see them? (And--what platform are you on?)

Thanks!

What are your cookie setting?

Do you allow all cookies or are you using another setting like "Ask me..."?
If you are using "Ask me" then try try to allow cookies for the current session (Keep until: I close Firefox)

• http://kb.mozillazine.org/Cookies

Do you have any extensions that deal with cookies?

I've tried all the combinations of cookie settings, both on the pages themselves, and in my firefox history settings. Blocking all, allowing all, session only, exceptions for the sites in question, make no difference.

And no extensions at all that deal with cookies. And, if I run in safe mode, it doesn't work (most of the time--strangely, it can sometimes work once but even if I go back in safe mode, it doesn't work the 2nd time).

DOES it work WORK for YOU?

And if it does work for you, are you on Windows?

Specifically--

Can you go to: www.browseryoulovedtohate.com and see ALL the Vines (they are about midway down the page) with no problem? And--if you then close Firefox, and go back, can you STILL see them?

I started having this issue with vine videos not playing recently. I updated my flash and java, cleared my firefox cache, and tried firefox in safe mode, but to no avail.

Setting the media.windows-media-foundation.enabled setting to false fixed the issue for me. Now the vine videos work. Not sure what caused the change in the first place though.

Ali that is the exact same with me, I think it was only in the past week or so that Vine videos stopped working. Did something change on Vine's end or Firefox?

I'm not sure but I think the windows-media-foundation setting causes Vine videos to play using flash as opposed the HTML5, although HTML5 videos on Youtube all seem to work

FALSE! This problem is NOT SOLVED.

This problem with Vine videos from Twitter failing to load and play properly occurs for me in Vista SP2 / 32 bit with the latest FireFox 23.0 and also with SeaMonkey 2.19 (and the latest SeaMonkey 2.20) ONLY. The latest Google Chrome (28.0.1500.95), Apple Safari (5.1.7), and MS Internet Explorer (9.0.8112...) play the exact same Vines perfectly, with no changes needed in cache options or configs.

This is CLEARLY a BUG with the latest releases from Mozilla, and is only a week or two old. It absolutely never happened to me on the previous FireFox or SeaMonkey versions. This is a MUST FIX on Mozilla's part, and has nothing to do with cache or config settings. Please go back and fix the BUG, or provide the correct solution.

Try to clear the Vine cookies. "Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > Cookies: "Show Cookies"

You can also try to modify the third-party cookie settings (either from visited or always).

• Tools > Options > Privacy > Firefox will: "Use custom settings for history"

• https://support.mozilla.org/kb/Options+window+-+Privacy+panel

If you use extensions (Firefox/Tools > Add-ons > Extensions) that can block content (e.g. Adblock Plus, NoScript, Flash Block, Ghostery) then make sure that such extensions aren't blocking content.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Thanks, Cor-El, but which part of my Problem Description was not clear to you? All those things and a great many more were tried and FAILED.

It is CLEARLY a new BUG that only appeared in the latest release or two of FireFox and SeaMonkey. It has absolutely nothing to do with AdBlock or anything else, unless the latest releases don't work with those add-ons. All add-ons were disabled to no effect. It has NOTHING to do with Cookies or Cache. I thought I was very meticulously clear about that, in the the Is / Is Not Differential Diagnosis description.

Please don't keep repeating the same ineffective "solutions". They do not work. It is a BUG in the latest, base FireFox and SeaMonkey releases. The problem goes away with earlier releases. It needs to be fixed.

I had a problem from the new update, all My videos would play with a weird color glitch. I couldn't find anything about how to fix it then I came upon this post.

Tried everything in it and ended up with what you were having, the video wouldn't play at all.

I ended up messing around with things in the config and what worked to fix it was to leave media-foundation ON but turn off "media.windows-media-foundation.use-dxva"

I don't know if this will help you but I'm posting this for anyone else who might be having the green lines on the right side of the screen while the rest of the video is a weird black and white with the rgb lines showing going on.

TheExiledLeader, If you're on Windows Vista and the problem began in Firefox 23 then it's likely this bug, which should be fixed soon was fixed in Firefox 23.0.1:

• Bug 901944 - Rendering glitches on H.264 video only in FF23 on Vista

is there a fix for this for us Windows 7 users?

To speedo

Since you are using Windows 7, the solution is what cor-el posted above. Set the media.windows-media-foundation.enabled preference to false in the about:config page. Details are in this new article:

• Vine and other HTML5 videos won't play

great, that fixed that problem.........now I am having trouble with instagram videos and some of their photos too. could they be related to the Vine problem.

the instagram videos aren't loading and either are their pics, the pics are a bit different.......after going to a users home pages I can click on the pic, but when wanting to view another one I have to reload the home page.

I hope that makes sense.