Yes, you can use Compressor for converting MP4 to apple Proress 422 LT at 4:3.
You have to drag your file to the compressor
http://gallery.me.com/danielsametz#100052/Paso%2001&bgcolor=black
and then instead of grabbing the proress setting to the video on the top you right click it and duplicate it. Then it´s going to be in personal folder (rename it as you please)
http://gallery.me.com/danielsametz#100052/Paso%2002&bgcolor=black
You click the new codec and then you can see in the inspector rectangle than you can change the settings.
http://gallery.me.com/danielsametz#100052/Paso%2003&bgcolor=black
In the small rectangles in the compressor in the top you click the second one from left to righ, when it says adjustments you click it, then you can change the FPS to 29,97 or whatever you like.
http://gallery.me.com/danielsametz#100052/Paso%2004&bgcolor=black
Then you click on the 5th square from left to righ or the second from right to left and then it says origin insertion or something like that, sorry but I have it in spanish, it´s gonna say personalized and you have to change it to 4x3
http://gallery.me.com/danielsametz#100052/Paso%2005&bgcolor=black
Then in the bottom of the inspector you save your new configured codec and drag it all the way to the video in the top and click send it
http://gallery.me.com/danielsametz#100052/Paso%2006&bgcolor=black
Now you have a video in 4:3 that is not stretched on the top and bottom with the right 4:3 conversion, you loose information on the sides so you have to be careful.
Message was edited by: Chocorito