I realize that you recommend against using.avifiles, but that's all I have. Should I first convert an.avifile to a QuickTime file by using a tool such as the QuickTime player?
First, if the only source file is an .avi file, you might as well use that. If it's good quality, great. If it's not, oh well. But converting it to a QuickTime file can't make it better.
I've embedded a video with a great music track. Why does the audio sound so terrible?
You need to set how the audio is to export via the Stream compression in the Flash tab of the Publish Settings dialog box. See Chapter 10 for more about sound compression. The key here is that the Stream setting is what affects the audio in an embedded video.
I know that the compression stage can take a long time, but even after I've compressed the embedded video, my Flash movie takes forever to export. Why is that?
Audio takes a long time to compress, and it's likely that Flash is compressing the audio at the time you publish. You can temporarily change the Audio Stream setting (in Flash's Publish Settings dialog box on the Flash tab) to Raw so that every time you do a test movie, it goes quicker. Just remember to set it back to a reasonable compression level before you export the final time.
Every time I attempt to compress a particular video (regardless of whether I select to make an external.flvor embed the video), Flash reports that the audio can't be imported. What's the problem?
Depending on the type of audio track in your video, Flash may simply not support it. You'll need to get an new source file.