Guys, There was a missing entry in the Makefile, which means if you're trying to build on x86_64 you are out of luck. The quick solution: * Download https://trac.xiph.org/browser/trunk/theora/lib/enc/x86_64/dct_decode_mmx.c * Modify the Makefile like this https://trac.xiph.org/changeset/15370 (it's just one line) Report back. -Ivo