xvid dev-api-4 (aka 1.0.x series) should be passed to transcodes configure script as default module with "--with-default-xvid=xvid4" to avoid mess while using. Reproducible: Always Steps to Reproduce: 1. 2. 3.
I've posted a cleanup ebuild which fixes the problem on bug #74806 . However, transcode's ./configure (from latest release avaiable from gentoo) reports xvid4 as default version.
fixes together with #74806, thanks to Diego