SUB_PIXEL_BITS     33 libavfilter/vf_perspective.c #define SUB_PIXELS      (1 << SUB_PIXEL_BITS)
SUB_PIXEL_BITS    310 libavfilter/vf_perspective.c             u  >>= SUB_PIXEL_BITS;
SUB_PIXEL_BITS    311 libavfilter/vf_perspective.c             v  >>= SUB_PIXEL_BITS;
SUB_PIXEL_BITS    389 libavfilter/vf_perspective.c             u  >>= SUB_PIXEL_BITS;
SUB_PIXEL_BITS    390 libavfilter/vf_perspective.c             v  >>= SUB_PIXEL_BITS;
SUB_PIXEL_BITS    400 libavfilter/vf_perspective.c                     sum = (sum + (1 << (SUB_PIXEL_BITS * 2 - 1)))>> (SUB_PIXEL_BITS * 2);
SUB_PIXEL_BITS    408 libavfilter/vf_perspective.c                     sum   = (sum + (1 << (SUB_PIXEL_BITS - 1))) >> SUB_PIXEL_BITS;
SUB_PIXEL_BITS    418 libavfilter/vf_perspective.c                     sum   = (sum + (1 << (SUB_PIXEL_BITS - 1))) >> SUB_PIXEL_BITS;