How to call Xlib function inside gtk library?

[hwang up elctech com]

Hi,

I am writing a video player, but there is a problem with my video
display. I am now using gdk_draw_rgb_32_image() to draw images at a
given rate in an infinite loop. But unfortunately, the image display looks
bad (seemed like it is skipping frames or something), the reason could be 
rgb_draw_32_image is slow.  

But when I write a test program using Xlib to show the video, the image
quality is fine. 

I believe it could be the problem with gdk_draw_32_image, so I am thinking
of calling Xlib function directly from gdk. 

My questions are:

1. Does anyone have such experience with the xlib and gdk interaction?
2. Does anyone know the reason why gdkrgb library function is slow?
3. Does anyone have any code example of calling xlib from gdk?

thanks a lot!

Sincerely,
Howard