how to relate 8x8 DCT to 4x4 DCT?

Dear all,

Can anybody tell me how to express 8x8 DCT in the form of 4x4 DCT?

8x8 DCT = function( 4x4 DCT) ???

Is there any simple relationship?

Thanks a lot,

-Walala

walala wrote:
> 
> Can anybody tell me how to express 8x8 DCT in the form of 4x4 DCT?
> 
> 8x8 DCT = function( 4x4 DCT) ???
> 
> Is there any simple relationship?

In the inverse direction:

  4x4 DCT = even_part_of( 8x8 DCT )

The odd part of the 8x8 DCT seems independent, though.

Regards
Guido