Conversions can take quite some time to complete. The least amount of time you should expect a conversion to take is slightly longer than the total duration of your video. So a half hour video will take at least one half hour to complete.
The higher quality your source video the more time you should expect your conversion to take. In addition, some videos, regardless of quality, may take longer than others to convert. If you're finding that conversions are taking too long you may want to try a different strategy for encoding your source material.
Normal users (i.e. users who are not pro account holders) are allowed two hours of conversion time per episode. Professional account holders are allowed up to six hours of conversion time per episode. Conversions that take longer than the allowed limit will be timed out to preserve conversion time for other users.
All videos are now being converted to M4V instead of FLV so the checkbox was removed. Pro users now get an additional HD conversion instead of just a iPod compatible M4V.
Pro users will automatically get an HD conversion when uploading a video with height of 720 pixels or higher.