Import FLV Files--Perian

You can play .flv files directly with VLC, and also convert the files to an iTunes-compatible format using the same software. Flash Video is really quite a mess as different "standards" are being shuffled around, but things are heading increasingly in an MPEG-4 direction, so perhaps in the future these files will be superseded by a more widely supported format.

See this informative article on the subject.

iTunes doesn't officially support Flash Video. If you got one file to work somehow, then that's great. But, since this is not a feature of iTunes, then I suppose that Googling for information regarding Flash Video, etc. might be useful to you.

The fact that the file has an extension of .flv actually means very little. You can take any iTunes-compatible video file and use the Finder to change the extension to .flv, and the file will still be playable in iTunes and QuickTime player.

I'm not sure, but it sounds like you're on an interesting path to discovery 😉

Some web browsers do different things with the same download operations behind the scenes. For example, downloading .bin images (from microsoft.com/mac, for example) with OmniWeb results in .bin images being saved to the default download folder, while using Safari results in .dmg files directly useable by OS X. Perhaps the TubeTV application you mention does some similar work to change the format of Flash Video files without doing any actual video recompression.

My wildest/best guess at this point is that perhaps, since Flash Video is indeed capable of using QuickTime-compatible H.264 video and AAC audio, certain files may be inherently playable by QuickTime and other QuickTime-based applications, regardless of the presense of the .flv file extension. If this were true, it would at least partially explain why certain (but not all) Flash Video files would open with iTunes. Again, this is just wild guess, and I personally just use VLC to play these files.