# emerge -va1 media-libs/phonon-gstreamer

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] dev-util/automoc-0.9.88  9 kB
[ebuild  N     ] media-libs/phonon-4.6.0-r1  USE="gstreamer (-aqua) -debug -pulseaudio -vlc (-zeitgeist)" 275 kB
[ebuild  N     ] media-libs/phonon-gstreamer-4.6.3  USE="alsa network -debug" 71 kB
[blocks B      ] dev-qt/qtphonon:4 ("dev-qt/qtphonon:4" is hard blocking media-libs/phonon-4.6.0-r1)
[blocks B      ] media-libs/phonon ("media-libs/phonon" is blocking dev-qt/qtphonon-4.8.4)

Total: 3 packages (3 new), Size of downloads: 354 kB
Conflict: 2 blocks (2 unsatisfied)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (media-libs/phonon-4.6.0-r1::gentoo, ebuild scheduled for merge) pulled in by
    >=media-libs/phonon-4.6.0 required by (media-libs/phonon-gstreamer-4.6.3::gentoo, ebuild scheduled for merge)