Can you explain the Video Quality choices in iVI?

Can you explain the Video Quality choices in iVI?

On the Conversion tab of iVI's Preferences there are two video quality choices, Normal and Highest. Highest does a full two pass conversion of the video for smoother playback quality. If you select your devices on the Device tab in Preferences then iVI will ensure the video is playable on your devices no matter what quality setting you choose. 

On the Advanced tab of iVI's preferences there are several additional choices for more advanced users. You can change the default bitrate for HD or SD conversions which will increase or decrease the file size and quality. Changing these settings may prevent iVI converted files from playing on certain Apple devices and so this is only recommended for users who understand these limits or for people using iVI for converting video for editing.