Suggested resolutions (these follow to the x16 rule for optimal compatibility)
1:2.35 movies: 720×304, 640×272, 576×240, 512×224, 480×208, 400×176
1:1.85 movies: 720×384, 640×352, 576×304, 512×272, 480×256, 400×224
1:1.33 movies: 720×544, 640×480, 576×432, 512×384, 480×368, 400×304