The problem is the CPU power which can't handle 25fps decoding...
There is a workaround for that, at least with PCs. Either have a graphics card with MPEG-2 decoding capabilities, such as the GeForce =>2 range (the decent models that is), or have an MPEG-2 decoding card.
Software would need to be written for AmigaOS in order to take advantage of the latter option though.