Compressor is a useful tool and can be used to convert video files for use on an iPod or iPhone.
One of the great things that Compressor can do is to not only tighten up your file size, but to convert it into a different type. Not all software or devices will support every movie type, especially directly out of your editing program. One of the more common types of devices that people will need to convert their file types is for the iPod or iPhone.
If you would like to do this directly out of Final Cut Pro, then you go about it the same way you would for any conversion. First, you go to File and Export using compressor. Once there, set the target destination, which should be somewhere that is easily accessible. Then go down to the Settings menu, and go to the Apple Devices folder.
Here you have three options: one for Apple TV and two for the iPod. One is of higher quality than the others so you must decide how much space you would like to end up devoting to this file. Once you select what iPod present that you would like to use, you drag it up to the project window where it says clearly to drag the settings. Here you can just compress it like normal, and the subsequent file can be imported into iTunes and synced to your iPod or iPhone. If you have a smaller amount of room on your mobile device, you may want to choose the lower settings to save space.
Basic File Conversion
The same can be done for any freestanding video files that you have available. Simply control click the file, and select the “Open With" option.
From here, select Compressor, and then go through the exact same steps. This is also a much faster way to do a large compression or conversion than doing it straight out of your editing software. Different base file types will take longer than others, but either way it should be conducive to your purpose.
A Great Alternative
It is possible to do this conversion in iTunes, but it is much less efficient. Using Compressor will likely be faster, and you will end up with a smaller file.