Largely due to the easily obtainable, cross-platform Flash Player, SWF files and FLV Flash video files are very popular on the Web. But buying Flash is a pricey proposition, so to produce these files something a bit cheaper is in order for the average user. In steps Moyea with its Flash Video MX Pro 5 video to Flash converter (US$89, free demo).
Flash Video MX Pro 5 proved rock-solid in my testing, and it produced high quality output. It sucked up a fair amount of CPU cycles, though; while I could still multi-task, there was a noticeable lag. While it'd be nice to have a CPU utilisation throttle, performance was more than acceptable -- even with wide-aspect HD resolution source files.
Rudimentary editing in the form of definable start and end points is provided. You may also choose from a number of skins for the playback controls that you can embed in a Flash video file. You may reduce or increase output resolution freely, and there's a handy lock that maintains the video's original aspect ratio, or doesn't, as you desire. Input file types include AVI, MPEG, WMV, MOV, MP4, M4V, 3GP, RM, ASF, RMVB, MKV, DAT, OGM, and ASX; output types include F4V, AVC/H.263/H.264, and Flash 8 to .SWF and .FLV containers.
Flash Video MX Pro is easy on the eye and easy to use. It provides all the options you could ask for, and does a nice job encoding. It's superior in nearly all aspects to the free Riva FLV Encoder 2 -- especially in output formats (Riva doesn't handle or output wide format or .SWF). However, since the latter is remuneration-less, you might want to try it before dropping US$90 on what is admittedly a very nice product.
Note: The demo version adds a watermark to the video and artifacts to the audio that are not present in the output of the paid version.