localhost ~ # emerge -p media-libs/win32codecs

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

Calculating dependencies
!!! All ebuilds that could satisfy "media-libs/win32codecs" have been masked.
!!! One of the following masked packages is required to complete your request:
- media-libs/win32codecs-20050216 (masked by: missing keyword)
- media-libs/win32codecs-20060611-r1 (masked by: ~amd64 keyword)
- media-libs/win32codecs-20060611 (masked by: ~amd64 keyword)
- media-libs/win32codecs-20061022-r1 (masked by: ~amd64 keyword)
- media-libs/win32codecs-20061022 (masked by: ~amd64 keyword)

For more information, see MASKED PACKAGES section in the emerge man page or
refer to the Gentoo Handbook.