You mean one viewport or two (one for album art and one for text)
With one viewport define the album art in the text viewport
%V|11|25|136|73|1|B8B8B8|000000|
%al%s%?C<%m|51|%?it<%it|%fn>|%?it<%it|%fn>>
%al%s%?C<%m|51|%?ia<%ia|Unknown Artist>|%?ia<%ia|Unknown Artist>>
%al%s%?C<%m|51|%?id<%id|Unknown Album>|%?id<%id|Unknown Album>>
%al%s%?C<%m|51|%?id<%?iy<%iy|%fc>|%fc>|%?id<%?iy<%iy|%fc>|%fc>>%ar%pp/%pe
%Cl|0|0|sc50|sc50|
%?C<%C|>

The font is 12pt, I see if you use two viewports then I can see the overlaping issue or if the text viewport is too small to fit the album art in.