QuickTime X exports increase bitrate


I use a basic script to export videos using QuickTime Player X. The weird thing is I get different file sizes compared to using the player itself. If you choose “Share → iTunes” you can choose to export videos too. Let’s say I export once using applescript and once using the GUI for AppleTV, then the file created by applescript can be almost double in size.

The problem seems to be the bitrate: if you use applescript, the bitrate is increased (obviously increasing the file size). If you use the GUI, the bigger export options (for instance AppleTV) might be greyed out. I suppose this is because the source file bit rate is too low. Then, I choose iPhone & iPod as export option.

Is there a way to obtain the same result with applescript? I suppose I should check the bitrate of the source file, and if it’s too low, I should export for iPhone or iPod instead of AppleTV. Right?

I also have some trouble finding what the maximum bitrate is before the QuickTime X export option is greyed out.

I also notice QuickTime 7 does not exhibit this behaviour.

Anybody? thanks