I wanted to leverage all of the nice videos that i acquired when i built my bartop so i switched from ES to AM. The problem that I found was that the performance was pretty sluggish on most of the nicer themes, even on a Pi 3. I wanted to make my own that removed all of the heavy lifting of the transitions and heavy code.
I did find that I had to downgrade all of my videos to 30fps to get them to run properly on the Pi. I paid for a subscriptions to emumovies to get the 480p movies, however they are 60fps. Most old games ran at 30fps anyways so no biggie they still look really good.
I am working on a dynamic positioning of the boxart (as you can see with the super nintendo, i need to reposition and shrink it a bit). I haven't found anything that works just yet with detecting the boxart size and calculating the top left corner based on the width/height of the differing systems boxart sizes. something like dividing the height of the screen in half for Y and subtracting half of the artwork height but it doesn't seem to work this way.
boxart.y = flh/2 - boxart.texture_height/2;