FireAnt does play SWF files. But Flash video is not a SWF. It is an FLV loaded into a SWF.. often loaded externally via relative link within the Flash file. This type of scenario often breaks syndication because it cannot be viewed offline or from a local hard drive. Syndicating the raw FLV file is preferrable as it doesn't require any dependencies on networked resources, but it is a little more difficult to play as FLV doesn't play natively within Flash player -- it must be loaded inside a SWF controller.
