Tools to check aspect ratio:
http://size43.com/jqueryVideoTool.html

Common resolutions:
http://en.wikipedia.org/wiki/List_of_common_resolutions

Aspect ratio 4:3
----------------
640x480
800x600
1024x768
1152x864
1280x960
1400x1050
1600x1200
2048x1536
3200x2400
4000x3000
6400x4800

Aspect ratio 16:9
-----------------
640x360
853x480
960x540
1024x576
1280x720
1366x768
1600x900
1920x1080
2048x1152
2560x1440
2880x1620
3840x2160
4096x2304
7680x4320

Aspect ratio 16:10
------------------
1440x900
1680x1050
1920x1200
2560x1600
3840x2400
7680x4800