refer to

• Flash Plugin - Keep it up to date and troubleshoot problems

• Flash 11.3 doesn't load video in Firefox

And try all the troubleshooting information.

Can you post a link to a publicly accessible page that doesn't require authentication (signing on)?

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

Check out lajollacreative.com/blog.html the first videos play but the last two have audio only. Thanks

The ones that show the video are available as HTML5 and use the built-in HTML5 media player.
The two that only have sound are not available as HTML5, but are played with the Flash player and that Flash player seem to be misplaced or otherwise is hidden.
I can't even right-click the viewing area.

• http://www.youtube.com/embed/nFeb6YBftHE?html5=1
  http://www.youtube.com/watch?feature=player_embedded&v=nFeb6YBftHE
• http://www.youtube.com/embed/qg1ckCkm8YI?html5=1
  http://www.youtube.com/watch?feature=player_embedded&v=qg1ckCkm8YI

Thanks cor-el. This is only happening in FF and just a couple of weeks ago played fine. Any suggestions??? Thanks

I don't know. I've checked it and it works in Firefox 10 and 11, but not in Firefox 12 and later.

The embed code still works (right-click: Copy embed HTML), only not on that page.

data:text/html;charset=utf-8;base64,PGlmcmFtZSB3aWR0aD0iNDgwIiBoZWlnaHQ9IjI3NCIgc3JjPSJodHRwOi8vd3d3LnlvdXR1YmUuY29tL2VtYmVkL3FnMWNrQ2ttOFlJIiBmcmFtZWJvcmRlcj0iMCIgYWxsb3dmdWxsc2NyZWVuPjwvaWZyYW1lPg==

Same problem for me, embeds previously working before FF 23.0 update.

• I have the latest Flash (11.8.800.94) tested and working.
• I restarted FF in safe mode.
• Navigated to http://www.reddit.com/r/videos

Embedded videos still do not work.

Edit: I tested http://lajollacreative.com/blog.html and those embeds are working for me. Seems to be reddit. But reddit embeds are working fine with Opera Next.

Edit2: I found the cause for me, was using https://pay.reddit.com, new FF 23 feature blocks insecure http content on https pages, indicated by a small shield next to the URL bar.

lajollacreative.com/blog.html Firefox 23: First video plays, but not consistently. Second two videos play fine. Fourth plays audio, no video and a message about the flash plugin flashes for a frame before going black.

Problem solved! I downloaded and installed Firefox 24.0 Beta. Apparently Mozilla programming team made all the right changes in the new release. Now all videos starting working on Youtube, Yahoo and BBC, etc.

Link: http://www.mozilla.org/en-US/firefox/channel/#beta

Thanks serge07, but just downloaded FF 24 Beta and the latest Adobe Flash Player and the problem is still there. I am not sure why. Cleared the Cache and all history as well. I have tried different ways of coding the vids but nothing seems to work.
Is there a piece of code I need to embed on the page? This is the code I am using on all the videos, <iframe width="480" height="274" src="http://www.youtube.com/embed/nFeb6YBftHE?html5=1" frameborder="0"></iframe>, the only thing that is different for each video is the individual code that is assigned to each video.
Again thanks to all who have responded.

That code work fine for me.

Here is a version that you can paste in the location bar.

data:text/html;charset=utf-8;base64,PGlmcmFtZSB3aWR0aD0iNDgwIiBoZWlnaHQ9IjI3NCIgc3JjPSJodHRwOi8vd3d3LnlvdXR1YmUuY29tL2VtYmVkL25GZWI2WUJmdEhFP2h0bWw1PTEiIGZyYW1lYm9yZGVyPSIwIj48L2lmcmFtZT4=

Are there any errors shown in the Browser/Error Console (Firefox/Tools > Web Developer;Ctrl+Shift+J)?

I've been having the same problem, and it seemed to me the difference between the YouTube embed code that works in FF and the code that doesn't is the presence of the "http:" in the src parameter of the embed code.

If you take out the "http:" in the embed code and just have "//www.youtube…", does it start working for you? Any thoughts on why this is the glitch?

This has been resolved, thanks to "clue" above from marteenzh. For me, the video displayed after I changed the http to https. My sites are secured connections. The video displayed as soon as I changed the url to http(s). As in SSL.

Thanks marteenzh and robertlang! I have tried both omitting the http and adding the (s) and neither seems to work. I am still working on a solution myself and can't believe that this isn't something I am overlooking. I continue to search and search the infinite wisdom out there but can't find an alternative piece of code to make this work. Cheers!

Try to boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if that helps.

lajollacreative if you are talking about using FF as just a web surfer visiting sites with videos, your issue is focused on addon scripts causing an issue, as well as outdated flash addons possibly.

However, if you are talking about videos not displaying on web pages as a web author, I can help you further. This is the embed structure I am using on a Wordpress powered website.

[embed]<iframe width="896" height="510" src="https://www.youtube.com/embed/iZ9WP9aiflY?feature=player_embedded&rel=0" frameborder="0" allowfullscreen></iframe>[embed]

It has been tested across four main browsers and is working on all of them.

I am running Windows 7 now and I was running XP and I had the same problem in both. What I did to correct the problem in both was go to Firefox Tools Addons and I disabled Shockwave Flash. You can find the problem by process of elimination by disabling plugins until it works properly. Let me know if this helps.

I have college instructors who are using YouTube videos in their online courses, and we promote FF as the browser to use in our learning management system (Moodle 2.4) - which is an https environment. We have had numerous calls about FF 23 problems where video embeds from YouTube, Kaltura, and TED.com do not appear. This is a serious problem. My solution for my setup (mac 10.7.5) was to downgrade to v22, but this is not a sustainable solution. This problem is messing a LOT of people up, and I hope v24 solves this quickly!

Steve Covello - Rich Media Specialist, Granite State College, Concord, NH

Make sure that in the case of secure https pages all content is loaded via a secure https link because otherwise Firefox may block it.

If content is missing or otherwise not working when a secure https connection is used then check if there is a shield icon to the left of the "Site Identity Button" (globe/padlock) on the location bar indicating that content is blocked.

• https://support.mozilla.org/kb/how-does-content-isnt-secure-affect-my-safety
• https://developer.mozilla.org/en/Security/MixedContent

@cor-el: YouTube does not offer (or, no longer offers) an HTTPS option for embed codes, even when their documentation says they do. So I have no way of "homogenizing" my content. Any suggestions?