How to insert .flv in iTunes library I have downloaded a flv file, and I would like to save it in iTunes library for later play. I guess I should convert it first, but is this supported by OSX or do I need an extra application. And which file format will keep the quality and the size of original video?
You can convert it to the mp4 and insert it. I use handbrake to convert or fix indexes.

Also you can give a try to Perian if it'll work in your OS.