these patches were already sent to the MPlayer project.
but were rejected for various reasons.

here is the post which announced the coreavc-linux project:
http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2007-July/052959.html

the coreavc codec is still faster than ffmpeg's ffh264 decoder. ffdshow has a multithreaded ffh264, but it was rejected by ffmpeg developers.

ffmpeg has a GSoC project for multithreaded decoding of most codecs.

http://code.google.com/soc/2008/ffmpeg/appinfo.html?csaid=9FD2BF705A5D5DBB