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

Calculating dependencies ... done!
Dependency resolution took 0.85 s (backtrack: 1/20).


!!! All ebuilds that could satisfy ">=media-libs/faac-1.28-r3[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_s390_32(-)?,abi_s390_64(-)?]" have been masked.
!!! One of the following masked packages is required to complete your request:
- media-libs/faac-1.31.1-r1::gentoo (masked by: MPEG-4 license(s))
A copy of the 'MPEG-4' license is located at '/Volumes/Disk 1/Repository/portage-git/licenses/MPEG-4'.

- media-libs/faac-1.30::gentoo (masked by: MPEG-4 license(s))

(dependency required by "media-plugins/gst-plugins-faac-1.26.11::gentoo" [ebuild])
(dependency required by "=media-plugins/gst-plugins-faac-1.26.11" [argument])
For more information, see the MASKED PACKAGES section in the emerge
man page or refer to the Gentoo Handbook.