Firefox and html5 videos

[razer]

I'm trying to have html5 video support in my firefox 15.1
All video test sites I tried failed with the message : "No video with supported format and MIME found", like this one for instance :
http://www.quirksmode.org/html5/tests/video.html

Firefox uses flags :
alsa, dbus, gstreamer, ipc, jit, minimal, startup-notification,webm

gstreamer installed packages :
media-libs/gst-plugins-bad-0.10.22:0.10
media-libs/gst-plugins-base-0.10.35:0.10
media-libs/gst-plugins-ugly-0.10.18:0.10
media-libs/gstreamer-0.10.35:0.10
media-plugins/gst-plugins-alsa-0.10.35:0.10
media-plugins/gst-plugins-ffmpeg-0.10.13-r2:0.10
media-plugins/gst-plugins-ogg-0.10.35:0.10

~ARCH

I have tried cleaning up my profile

Thanks for help

[razer]

resolved after a check of media-plugins/gst-plugins-meta use flags
Seems to be working without gstreamer flag, nevertheless