https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues

I filled the "Troubleshooting" text field when I was posting my request. For some unknown reason the troubleshooting block is not shown here, so I will copy it into this reply post. Together with that I would like to mention, that no solution helped from the previously posted recommendation (I already tried all that stuff before opening this topic).

1) I re-installed FF - no effect - same problem.

2) Turned off the Adobe Flash Player plugin in the FF settings - when trying to open a resource with embedded video, I get error, that the Flash Player plugin is not installed (as expected).

3) The previously posted "solution" has no relation to the problem I got. I have FF ver. 15.0.1 (not 13) + Adobe Player plugin ver 11.4.402.265. Even though I tried to downgrade the Adobe Player plugin to 11.2 - no effect, same problem.

4) I get NO problem with same version of Adobe Player plugin and IE on the same computer.

5) I got NO problem with same FF version (15.0.1) and Adobe Player plugin (same version - 11.4.402.265) on another computer, which runs on Win 7 32 bit (!). Could it be the key?

Thank you.

I would like also to remind, that the video (embedded) is NOT shown, but the sound is played (!) and the right mouse click on the embedded video clip shows the Adobe Player options. That means that the plugin works, but partially.

I too have this problem and would dearly love to fix it. Any advice?

You did get the version of Flash plugin for browsers other than IE, right? IE requires a different type of plugin from other browsers. If you want to use Flash with IE and Firefox, you need two Flash plugins. See this page:

• http://www.adobe.com/products/flashplayer/distribution3.html

Finitarry,

I got the Flash plugin, which is installed automatically via Adobe Update. Did it using FF.

Anyway I tried the link you've sent and tried to use the option:

Windows / Plugin-based browsers / All supported languages / Download EXE Installer.

Got exactly same results - no embedded video, only sound and right-mouse options.

Please, provide more (working, if possible) ideas.

Uninstalled Flash Player 11 (active x + plug-in) completely. Checked the results on one of sites with flash content - got message that "a plugin is required".

Went again to the Adobe link (posted previously), downloaded ONLY the Flash Player 11 Plug-in (for Mozilla, Opera and other browsers) and installed it only (without Active X plugin for IE this time).

Got exactly same bad results for embedded video clips:

Audio - OK, Right-click options - OK, Video - NOT OK (blank grey bar).

Please, advise.

FIXED my problem:

Upgraded graphics card driver and boom...everything was dandy

Does the problem happen if you use Firefox safe mode? It could be hardware acceleration causing the problem, or an extension.

1) Started the FF in Safe Mode.

The embedded video works normally (!!!)

2) Re-started the FF in normal mode - got the problem.

3) Disabled ALL plugins and ALL add-ons (except the flash player) in Normal Mode - got the problem (once again, ALL plugins / add-ons were disabled).

Safe Mode - everything works. Normal Mode - problem occurs (with no relation to disabling plugins / add-ons).

Looks like there's something built-in FF which has the problem with showing embedded video normally in FF Normal Mode.

Try disabling hardware acceleration in Options > Advanced > General.

Finitarry - thank you very much! It worked :)

The problem of "no video / sound OK / controls OK in embedded video in FF" was solved by "Disabling the HW acceleration" in FF.

Issue is closed.