Astuces Développeur Multimédia

Tester les sites Web avec les différentes version du Flash player avec Flash switcher

Installer le plugin Flash Switcher sur Firefox

Copier le contenu de l'archive dans le dossier :
C:\Documents and Settings\{USER}\
Application Data\Mozilla\Firefox\Profiles\{szro7hst.default}\
extensions\flash_switcher@sephiroth.it\chrome\plugins

Une article très complet vous donne la réponse.

How Flash Video Works

Flash is a very serious force in the world of streaming video. This is the format we recommend most strongly.
Flash uses two main formats: .swf for standard Flash files which are used in web pages, and .flv which is a special Flash video format. flv files can be called from within swf files. As of late 2008 Flash also supports H.264 files, which is a significant leap forward.