The stars are really quite huge though, they need a full row, like the song title basically.
Even if i shrink the seekbar and buttons slightly, and the stars as well, it won't fit without taking space from the cover art as well, and since we don't want to cut the cover art, it'll open up even more space left/right of the cover art.
Vertical stars looks bad as well, since it smashes the cover art against the side of the screen and destroy the symmetry.
Many other players I have looked at only have a "thumbs up" and "thumbs down" icon, which are quite easy to hide, say at the left/right end of the seekbar (in googles music player, for example)
And they blend content over the cover art as well. Usually so that the cover art is stretched over the whole background, ie:
Google Music