The Optimal Video Resolution option in the resolution drop-down list instructs Encode 4i to re-encode your videos at the same video resolution of the original file.
If the original video file was recorded at a resolution over 720P and Optimal Video Resolution is selected, Encode 4i will automatically adjust the video resolution to ensure that the file can be played on your iPod Touch, iPhone or iPad.
If iTunes is not configured to allow you to manually manage the videos on your iPod Touch/iPhone/iPad, Encode 4i will not be able to sync your encoded videos.
Checking the "Manually manage music and videos" option under the Device Summary section in iTunes will make it possible for videos to be synced:
Thanks to a low process priority configuration and dynamic CPU usage, Encode 4i ensures that your computer will remain fast and responsive while converting your videos, allowing you to multitask with ease.
If you right-click on a file in the video queue list, a Preview option will be displayed. Selecting it will allow you to preview the original video file, before and/or while it is being encoded.