I must be a bit dense trying to compile theora support into mplayer/mencoder and not being very successful at it. I installed libtheora 1.1.1, configured, make, installed and make checked it and libtheora seems content. However, mplayer configure keeps complaining about: C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cclq6Twi.o:mplayer-conf-5713-2228.c:(.text+0x19): undefined reference to `theora_info_init' C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\cclq6Twi.o:mplayer-conf-5713-2228.c:(.text+0x28): undefined reference to `theora_comment_init' Of course, there is a theora.h. I don't have a libtheora.dll but libtheora-0.dll, libtheoradec-1.dll, libtheoraenc-1.dll from my libtheora build. Do I have some sort of version conflict here? What other diagnostics are useful. The whole configure log is a bit long. /re