Following the instruction on Scott's blog, I succeeded posting my first ever flash video. You can see it here: Jet's video.
It took me about 2.5 hours to get everything working correctly. The first problem that I encountered was: Flowplayer didn't display the flash video. It just gave me a blank screen. Below is the code snippet that I use:
The other hurdle that I encountered was no sound on the flash file produced by FFmpeg. The source video that I have is a .MOV (Apple's Quicktime?) file. For .MOV files, it turns out that I have to specifically tells FFmpeg to specify MP3 as the output audio codec for the output. On my FFmpeg installation, mp3 is not installed, so I have to re-compile FFmpeg. Found out how to do it from: http://ubuntuforums.org/showthread.php?p=651946</a>.
And finally this is how I execute FFmpeg to produce the desired flash video: