iTT (iTunes Timed Text) subtitles
An industry-standard format for delivering onscreen text synchronized to the audio or video of a video program. iTT subtitles can be used to deliver foreign-language translations or a transcript of dialog, narration, or audio descriptions for the hearing-impaired. iTT subtitles, which use the .itt filename extension, offer more limited formatting options than CEA-608 captions. In Compressor, you can specify whether to let viewers turn iTT subtitles on or off (for example, for full foreign-language translations) or force subtitles to appear onscreen (for example, for specific characters in a movie who speak a different language). In Compressor, iTT subtitles are compatible with iTunes Store packages, the YouTube and Vimeo destinations, and many transcode settings.