Avalon ST processing

Hi,

I'd like to know if the following design can be done (workable) or not:

In SOPC builder, I have :

Clocked video input > My component > Frame buffer > Clocked video ouput

In CVI, there is a 1366x768 video.

Frame buffer and CVO are configured for a 800x600 video.

In my component, I want to remove some pixels, that's why I have a process which copy incoming data from Avalon ST sink to Avalon ST source, and I use the Valid signal to discard some pixels (I put Valid Source low instead of high).

Like that I discard some pixels, to have only 800 x 600 valid pixels.

But there is no activity at the output of the Frame Buffer...

Do you think such process can be done? (or do I have to store video in DDR and read back some part of data?)

Thanks for your help,

Francois