Beamer: how to play movies in their original size

Beamer: how to play movies in their original size

When using the beamer/multimedia package, you must specify the width and
height of the movie like this:
\movie[width=8.0cm,height=8.0cm]{}{movie.avi}
The problem is that the video loses quality due to resizing.
How do I make beamer show the video in its original size, i.e. the same
size as when I play it in VLC or Media Player?
I tried putting the size of the video in pixels like this:
\movie[width=600px,height=600px]{}{movie.avi}
But beamer displayed it much bigger than it should.