how can i scale big pixbuf in realtime?

["chen zhixin" <thexin1985 gmail com>]

hello
i have to scale the image i recived,NTSC,30f/s,yuyv->gray and 720*480
because i need to do something on image,so i use gray->pixmap,and use
cairo_t to do .
then i must scale the 720*480,
use gdk_pixbuf_scale make cpu to 100%.

is there a better way to do this?
thanks