[PD-dev] [GEM] several additional changes checked in

[guenter geiger]

Hi there,

I hope nothing went wrong with this checkin, if so, please let me know.

Here it goes:
1) removed the MMX code (was not good and fast enough)
2) enabled fast processing in pix_convolve, pix_add, pix_sub using
manual loop unrolling and int calculation.
3) added experimental ffmpeg pix_film support. the movie is still
the wrong way round and seeking in the movie is not possible.

Please let me know if this still works on other platforms, especially
OSX with RGB processing.

I discoverd a bug when changing from the object from pix_add to
pix_subtract ... have to track down why ..

Greetings,

Guenter