We are currently unable process SWF files through our encoders. They may upload, but will fail encoding. We recommend you convert SWF files to one of the our suggested formats (namely, MP4 or MOV) before uploading to Viddler. The SWF format was originally the intended for interactive multimedia (such as a video player), (animated) vector graphics and ActionScript. Thus, it doesn't do well as a video container. It's a format which is quite difficult to convert to another video format.
How can I convert my SWF file to a video format?
Our team has tried using several of the most popular "SWF to FLV/MP4/et al." converters with no success of creating a useable video file. (Frankly, all those programs look suspicious and we don't recommend you download them to your computer.) The best one we could find actually just recorded the portion of the computer screen where the video was playing and output it as an MP4. Hence, if you don't have many files which need converting, we recommend just using a screen recorder to capture the playback of the video. Perhaps displaying the video full screen will be the best experience for this. You can then upload the file output by your screen recorder to Viddler.