First install ppa:skunk/pepper-flash – this will install Chromium and with only one edit of /etc/chromium-browser/default , it makes Pepper-flash from Chrome get working under Chromium. See https://launchpad.net/~skunk/+archive/pepper-flash for more info.
Second step is installing ppa:nilarimogard/webupd8 which also makes it work under Firefox. Edit the file ~/.config/freshwrapper.conf and add the following line to it:
plugin_path = “/usr/lib/pepflashplugin-installer/libpepflashplayer.so”
Ofcourse almost nothing is documented and you need to find things out yourself, but hey.. you could also have just installed Chrome and then acceleration just worked rightaway.
While you’re at it, also add “MOZ_USE_OMTC=1” to your .profile and have hardware accelerated Firefox too. And yes, it makes a lot of difference.
For who forgets each time (like me):
sudo add-apt-repository ppa:skunk/pepper-flash
sudo add-apt-repository ppa:nilarimogard/webupd8
I hope it helps.