http://forums.creativecow.net/thread/2/940078
In adobe after effects:
::::
#define PF_MAX_CHAN8 255
#define PF_HALF_CHAN8 128
#define PF_MAX_CHAN16 32768
#define PF_HALF_CHAN16 16384
#define CONVERT8TO16(A) ( (((long)(A) * PF_MAX_CHAN16) + PF_HALF_CHAN8) / PF_MAX_CHAN8 )