Poor видео выступление in Firefox

гd like to try to переключатель back from Chrome to Firefox, but there is an issue that makes it impossible. When I play any видео with Firefox it works very slow and quality worse than in Chrome. For example, when I expand the видео to fullscreen it переключатели very slow and the only way to exit fullscreen mode is to press Esc. But in Chrome all works умер. гve recorded в видео with в demonstration of it. Please, check this out. My system is Xubuntu 14.04, видео Radeon HD 7640G with fglrx драйверы.