Why motion cannot be estimated in DCT domain using block match? In all video coding standards, motion estimation is always done in pixel domain using block matching. I wonder why it cannot be estimated in DCT(Discrete cosine transform) domain using block matching directly? If two blocks are similar in value in DCT domain, doesn't it mean that they are similar to each other in pixel domain as well?

All the comments and suggestions are welcome!!!
Thank you!
Block matching will only work well if the pixel offset is (close to) a multiple of the block size, in both dimensional axises.  Odds against that might be (8*8-1):1 or (16*16-1):1.