In the rare case that the SWF contains the video embedded in itself, you can use a tool to extract it, oddly enough some versions of ffmpeg do this. You probably want to convert them, which is trickier, but there's some ffmpeg guides with parameters to be found online. All these flash video players can help you play SWF contents like games, movies or animations. SWF File Player is a free player for SWF (Shockwave Flash) files that can quickly open SWF files and read metadata tags from the file header. Here is a list of 5 best SWF players for Mac, Windows and online browser. They can be played back with an FLV player (there's a couple, most are iffy), or in a container built with flash, or Adobe Air. Whether you want to play a downloaded SWF file, or just open a flash video in SWF format online, you need a SWF file player. FLVs are often streamed over plain HTTP, and can therefore, once you find the url with the aforementioned inspection, be downloaded simply.

The best thing to do is to use a browser plugin like tamper-data, fire-bug, safari's web-inspector resources, or a proxy to watch all the requests made while it is running the SWF. The link will explain the various encoding that may be in play (H.263, H264, On2.). Most flash swf container have their video encoded as an flv or f4v. The SWF is usually streaming the video, alternatively it could have the video embedded in it. Although the URL for the SWF will be in the page source, in most cases this will not help you.

Play swf files online