I have YouTube videos embedded on my website and some of them will play and some will not. This happens on both PC and MAC so is not OS specific and all the embedding coding on the website is the same. When I first embedded the videos they all worked, now only certain ones play. The ones that will not play have a black screen and audio only plays.
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).
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.
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.
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Same problem for me, embeds previously working before FF 23.0 update.
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.