Is there a test website we can use for this purpose? Is the video playing directly in the browser or being played using Firefox via an external 3rd party video player?

Is the device a LG G2X ? Please see Will Firefox work on my device

Flash might not be supported on your device for the following reasons:

*Your device is using a custom ROM or is a Tegra 2 device running Android 4.0 or higher 

Flash support is not enabled in Firefox for your device because the experience did not meet an acceptable standard of quality in our testing.

We apologize for any inconvenience this may cause you.

• • EDIT This is incorrect! please see James's post!

Andrew, in fact I was tying to play videos directly on the browser. But I think guigs2 brought us the answer, despite a solution would be better than a reason...

The reasons that guigs2 posted are a bit outdated and vague now though.

Tegra cpus like Tegra 2 may not be blocked anymore as per Bug 777746 - Remove Tegra blacklist for Flash

The more current reasons why Flash may not work is if the phone/tablet has a Intel cpu and not a ARMv7 or v6 type of cpu that old Flash 11.1 for Android supports.. And if you have Android 4.1 or newer you need Firefox 27.0 and newer.

In fact, I AM using a lg g2 (D805) with Android kitkat which can play videos through stock browser and chrome...

Just the installation of the newest version of the old Flash player could solve the problem. Flash can be taken here http://helpx.adobe.com/flash-player/kb/archived-flash-player-versions.html

Hi all!

I have the same issue as topic starter had, but with some differences. My system: Fennec 32.0, Teclast x98 3g on Intel Atom z3735D, Android 4.2.2, Shockwave Flash 11.1 r112. When I switch on "Settings" - "Full version"(PC mode) and try to play any flash I see only black rectangle, but I can hear audio. Also I noticed weirdness - I can see some flash movies when I switched to Full Screen mode. If I disable "Full version"(Mobile mode), I can play back almost any flash without any problems, but still have very small percent of flash videos, that couldn't be played in Window mode(no video, only audio), but in Full Screen mode play back is ok. I also tried the same flash videos in other browsers - Embedded, UC Browser HD, Chrome. They play them flawlessly both in Mobile mode as well as in PC mode. What logs could I show you to fix this issue?

Thanks in advance.

Flash was never made for Intel x86 CPUs on Android. We only support flash on ARMv7 CPUs on Android.

Thank you for your reply. Ok, Flash was never made for Android x86, but how am I playing flash video in Mobile mode of Firefox and in PC and Mobile modes of other browsers that I mentioned above?

Depending on what you are viewing the site might not be using Flash.

I checked every site and Flash is using there, because when I disabled Flash plug-in I saw no video, only request to download Flash Player, when I turned on Flash plug-in I could play this video. Any suggestions?

As has already been related, if chrome and stock (to stay with just these ) browser play the videos Firefox doesn't, it's seems to be a clear Firefox bug. 2 months gone since the topic was proposed. Any way this arrive Firefox 's developers?