CoreAVC is a proprietary Windows codec for H.264 video decoding. It is much faster than any currently available open-source codecs. Being multi-threaded, and able to play PAFF streams, it can handle HD H.264/AVC streams that no freely available codecs can. CoreAVC is reasonably priced at ~$15, but it is Windows only. Various patches are available here to enable loading CoreAVC into 32bit and 64bit linux players.