Apple Final Cut Express HD - Manual (Page 990)

990 Part XII Output
The Export Using QuickTime Conversion Command
Unlike the Export QuickTime Movie command, which only exports to a QuickTime
movie file, the Export Using QuickTime Conversion command allows you to export to
almost any file format QuickTime supports, using any video and audio codec supported
by that format. Everything is customizable: image dimensions, frame rate, audio
sample rate, video codec, audio codec, and so on.
Note: Because QuickTime has extensive support for most codecs and file formats, there
may be a lot of options for some formats.
While the Export Using QuickTime Conversion command may seem advantageous,
there are times when the Export QuickTime Movie command may be better. For
example, Export Using QuickTime Conversion always recompresses your media, even if
you select the same codec. The Export QuickTime Movie command has an option for
not recompressing frames, reducing unnecessary artifacts when exporting to the same
video codec.