250 frames @ 1024x576
=====================

ppmtoy4m -v 0 -S 444 -F 25:1
----------------------------
3.92user 0.21system 0:04.15elapsed  99%CPU (0avgtext+0avgdata  9888maxresident)k 0inputs+0outputs (0major+ 678minor)pagefaults 0swaps
3.93user 0.16system 0:04.09elapsed  99%CPU (0avgtext+0avgdata  9904maxresident)k 0inputs+0outputs (0major+ 679minor)pagefaults 0swaps
3.90user 0.21system 0:04.11elapsed  99%CPU (0avgtext+0avgdata  9888maxresident)k 0inputs+0outputs (0major+ 678minor)pagefaults 0swaps

./ppmtoy4m_quickndirty 1024 576
-------------------------------
0.90user 0.28system 0:01.17elapsed 100%CPU (0avgtext+0avgdata 16240maxresident)k 0inputs+0outputs (0major+1058minor)pagefaults 0swaps
0.91user 0.25system 0:01.17elapsed  98%CPU (0avgtext+0avgdata 16240maxresident)k 0inputs+0outputs (0major+1059minor)pagefaults 0swaps
0.90user 0.27system 0:01.17elapsed 100%CPU (0avgtext+0avgdata 16240maxresident)k 0inputs+0outputs (0major+1058minor)pagefaults 0swaps

summary
-------
350% speed boost