Actually, upon further review... SWF files deliver vector graphics (especially anima-tions) and other data types over the Internet. SWF files also allow viewer interaction, such as following a web link. To view SWF files, you need Adobe Flash Player, a plug-in for your web browser. FLV files contain only video, not vector graphics, and they aren’t interactive. FLV output can also contain an alpha channel, for compositing of FLV with other elements. FLV files may or may not be contained in a SWF file. To view FLV files, you need Flash Player 6.0 or later. Because the Flash Player is very lightweight and nearly ubiquitous, embedding FLV in a web page is a terrific way to conveniently distribute video to a very wide audience.
This is taken from http://media.studio.adobe.com/linked_content/en/aft7it_exportflash/aft7it_exportflash.pdf.
I was thinking .fla while responding to .flv -sorry.
Yes. But apparently though, flv is more for video, while swf can contain video, it is more for animation or graphics or even items that need to be interactive.
When I switched over to Flash8 from wmv a few months back, I tried to learn a little about this whole "Flash" thing. I still don't know very much, but I understand there are several ways of showing video. One way embeds the video into the web page. The problem with this approach is that your browser has to load the whole video while loading the page. The second way is to stream the flv file when requested. This is the approach I use, since it means all you're loading on the page is a trivially-small embedded player. Only when you click on the play button does the player go out and stream in the Flash video file. Works great on all the browsers.