You should be able to get a pretty good quality video at 768kbps. If you are not, there may be some other issues involved, such as poor compression codec, encoding for the wrong size screen, poor quality original video, the list goes on.. What size screen are you using to view the video? Decrease the size of the video player screen and see if the quality improves.
Any given bitrate will only display high quality video on a certain size (or smaller) video screen. For example, a 400kbps video will display a high quality video on a 320 X 240 screen, yet would look terrible on a 640 X 480 screen. Why is that? Well it requires 4 times the data to provide the same quality. So it would require a bitrate of 1600kbps to provide the same quality at the larger screen size.
When you say you've started on a another video, what do you mean by that? What have you done so far, details please.
Here are some of the stats for the video that plays on that site when it first opens up:
So it's a little bit higher bitrate but not much.
A typical Flash player is a .swf file, which reads from an xml file the urls to a video playlist, has nothing to do with quality, just a good way to populate a playlist.
You maintain high quality and fast download speed by correctly sizing the video display screen to match the bitrate. There is nothing you can do to influence a viewers Internet connection speed. So if your viewers range from 256kb DSL lines to 10 Mb cable connections, you might want to provide a high and low bandwidth version.Lower Internet connection speed, smaller display screen. Higher speed connection allows you to display on a larger screen.
Progressive downloading is when a video file downloads into a buffer on the viewers machine, after a small amount of the file has downloaded, the video will begin to play, while the rest of the file downloads. In case you're wondering, that video will end up in the visitors Temp Internet Files folder.