Firefox fullscreen flash lags/freezes

[Darnording]

Hi all!

Problem: Flash videos in Firefox lag and freeze only in full screen (small ones play very well).
Same video works properly (full screen) in Opera.
In Chromium the sound is a little scratchy and the video gets a border with a close button (=not a real full screen mode) but without lags or freezes too.

I'm able to run full screen videos in Firefox only when i change the AMD driver from fglrx (proprietary) to xserver-org-video-ati (open source).
But thats no solution for me because with the open source driver i get artifacts when i play games and my PC needs +10 Watt in desktop mode.
I also installed the latest beta driver from AMD without improvement.

Why does Opera work and Firefox not?

EDIT: I also tried edit/create: /etc/adobe/mms.cfg
EnableLinuxHWVideoDecode=1
OverrideGPUValidation=true
without performance improvements.

EDIT#2: When I start the video, go into full screen and press at the same moment the right mouse button to show the context menu with 'settings, global settings, about flash player' it works flawlessly. But when I close the context menu it starts lagging and freezing again.

EDIT#3:Had couple of updates today (see screen shot). Seems that Firefox 31 solved my Problem.

EDIT#4:False alarm. After reboot flash videos in full screen lags again. =(

----
Processor : 4x Intel(R) Core(TM) i5-3570K CPU @ 3.40GHz
Memory: 16397MB
Operating System: Linux Mint 17 Qiana
Kernel: Linux 3.13.0-29-generic (x86_64)
Desktop Environment: X-Cinnamon (default)
OpenGL Renderer: AMD Radeon HD 7800 Series
Audio Adapter: SB-XFi - Creative X-Fi
----

[hyperion1is]

I have a similar problem with the difference that it runs "slow" on Opera and Firefox.
It's a performance issue from the user point of view. When it runs a youtube video on 480p my Cpu is at 40% and some lags and garble here and there. On full screen almost 100% CPU usage and more lag (in image).
On windows 7 (I have dual boot) I can watch videos at 720p smoothly, not at 1080p indeed, but still better than on linux.

I have:
Linux Mint 17 Mate.
Intel Pentium D 2.66 Ghz
Nvidia 6600 256 ram.
Nvidia-304.117-0ununtu1 driver.
Can you help? It just a performance thing, in the sense that linux mint can't match windows 7 performance on this issue? flash? Or I'm missing something. Please help!

[ingullar]

The same problem, but not with Firefox only. I have this lags with Google Chome and Chromiun browsers also, on any fglrx (doesn't matter from AMD website or not)

Intel Core i5,

ATI Radeon HD 7700, 1024 RAM,

Linux Mint 17 Mate

[3KyNoX]

Same for me, saw no workarounds currently.

[reveur81]

Sale issue here, flash is very slow on fullscreen, with Firefox only, no problem with Chrome.

[Lukasman]

Lately I've been having the same issue with chromium and firefox, while everything's OK in Opera.

Has anyone come to a solution?

[mikehell]

Hi All

I have same problem (also Radeon HD 8330 card) chromium and google chrome works fine but firefox lags in full screen mode

[Lukasman]

New version of radeon drivers solved my problem with chromium, but with firefox I still have the same issue.

[Darnording]

All problems solved. =)

Updated:
Linux Mint to 17.1
Catalyst to 14.9
Kernel to 3.13.0-40

I think the new Cinnamon 2.4.5 version fixed it. But am not sure about it.