Save(If(And(Compare(ListItem([Dimensions],0,/ x/ ),=,ListItem([Crop],0,:)),Compare(ListItem([Dimensions],1,/ x/ ),=,ListItem([Crop],1,:)),Compare(ListItem([Crop],2,:),=,0),Compare(ListItem([Crop],3,:),=,0)),0,1),v_IsCropped)/
Save(Replace(Math(ListItem([Aspect Ratio],0,:) / ListItem([Aspect Ratio],1,:)),/,,.), v_ARDecimal)/
Save(Math((ListItem([Crop],0,:) / [v_ARDecimal]) / (ListItem([Crop],1,:) / [v_ARDecimal])),v_ARCalculated)/
If([v_IsCropped]/
,Save(Replace(Math(ListItem([Aspect Ratio],0,:) / ListItem([Aspect Ratio],1,:)),/,,.), v_ARDecimal)/
Save(Math((ListItem([Crop],0,:) / [v_ARDecimal]) / (ListItem([Crop],1,:) / [v_ARDecimal])),v_ARCalculated)/
,Save(Replace(Math(Replace([Aspect Ratio],:,//)),/,,.),v_ARCalculated)/
)/
IfCase([v_ARCalculated], 3, 1, empty, 1.38, 1.33, 1.69, 1.66, 1.80, 1.78, 1.88, 1.85, 2.37, 2.35, 2.45, 2.39)
Haven't check the math from anywhere so probably not right but anyway this is what I'm using. If there is no cropping then just use Aspect Ratio got from MediaInfo, otherwise try to calculate it.
@jmone: If you could add configuration for -ss and -t values it would be great. Current values work for most but not all the time