Apple is giving vloggers a few hints on how to optimize their videos for iTunes so that a single format will look ok on both an iPod as well as the new Apple TV, which is probably connected to a large screen HDTV.

An email went out today to content creators who already work with iTunes, pointing them to this spec page. In the email they also make a few specific recommendations:

• Encode at 640×480 or 640×360. This will look much better than 320×240 on HDTV, and will still port to the iPod. While 720p looks great, they say, it won’t work on an iPod.
• Don’t make two formats for different resolutions – it dilutes the popularity of the podcast and reduces exposure in charts.
• Don’t add letterboxing to make videos to a 4:3 aspect ratio. Leave them at 16:9.

See the original email here.