problem while displaying D5M image data on LCD using VIP core

Hi all,

I'm trying to use the D5M camera and an LTM LCD touch screen connected to DE4 board using Altera VIP open core. The block diagram of my design is described in the attached picture. In Nios system, the 800x600 D5M RGB pixel data(which is the output of D5M custom IP) is used as the source of Clocked Video In IP core, followed by Frame Buffer which write pixel data into DDR and retrieve them from DDR, Clipper which generate the 800x480 to suite the LCD and then followed by Clocked Video Out, the 800X640 RGB output is directly connect with LCD.

As I don't need any runtime control, none of the IP core is connected with avalon bus, When I downloaded the design onto the board, there are data on the LCD but they are not synchronized at all. My DDR clock is set to 400Mhz and other nios2 components uses 200MHz as system clock. I'm posting my Qsys system and the top module of my design, could any on take a look at it and tell me what could probably the problem be? If my design is wrong, is there any other way to display camera data on the LCD? Could you please give me a hint, I'm already stuck for more than two weeks. Thank you very much