1.3x and 3% on G4.
Though I think only part of this speedup is due to my optimizations per se;
some of it is that I got a better roll on the GCC random code generator.
Trivial reorderings of this function have a disproportionate effect on speed.



git-svn-id: file:///var/local/repositories/ffmpeg/trunk@19726 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b