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

Calculating dependencies ... done!
Dependency resolution took 1.01 s (backtrack: 0/20).

[ebuild  N     ] x11-libs/libXv-1.0.13::gentoo  USE="-doc" 275 KiB
[ebuild  N     ] media-libs/libmpeg2-0.5.1-r3::gentoo  USE="X -sdl" 513 KiB

Total: 2 packages (2 new), Size of downloads: 788 KiB