Mutter: high CPU usage playing movies

[Alessandro Crismani <alessandro crismani gmail com>]

Hi everybody,

I am experiencing an high CPU usage (stays around 22% of a core of a
Intel i5) of Mutter when playing DVDs (from ISO copies, I will try the
original DVDs but I think it will be the same) using Mplayer / Totem.
Shell is from git master, and it has been happening for some time (maybe
always had, I just noticed some time ago). Note that it shouldn't have
anything to do with decoding the movie, which is handled without any CPU
notice by Mplayer (vdpau) while it takes another CPU slice with Totem
(so 22% + Totem).

This does not happen with Metacity, where the CPU usage stays low (apart
when using totem, which doesn't have support for vdpau, however when
using the Shell I still have to add that 22% from Mutter to Totem
usage).

I hope I was clear. Is this expected, should I file a bug? How to debug
it, I may provide information but I do not know which logs might be
useful. It eats my  battery and makes my PC overheating :(

Cheers,
Alessandro