If you have run across problems with Flash and audio exporting to MP3 you have come to the right place. Sadly I have become and expert in this over the past couple of weeks.
The easy fix is of course to upgrade your Flash player. Since the Flash player in IE, Safari and FF for Mac all seem to be fine. But for PC it seems to be a vexing problem.
This audio problem should not be confused with the dreaded PC audio not playing at all problem which is basically all your find when you look for this topic.
This problem stems from bad AIF or WAV files and continues through Flash CS4 right through to the output stage. An easy fix for this problem is to bring your MP3 compression export to 56kbps or below, but for those of us who like sound this is just not gonna do it. You can see what might be the cause of this audio problem, by the fact that this info panel for a piece of audio has an author of “Pro Tools”. In my case all the other audio was fine except for these files which had an author of pro tools.
The first thing to do is to redo the audio files.
1. Open them in your audio program (Soundforge, Soundtrack pro, etc..) and copy and paste the audio into a new file and save it as new file.
2. Delete the audio that is in your Flash file and re-import the new sound files and place them in your timeline, actionscript etc..
3. Goto “publish Settings” and set your MP3 Kbps setting to 80 or above for better sound settings.
4. uncheck the “compress movie” setting just to make sure they is no more compression taking place
5. Republish your SWF
This has worked for me, but it might not solve all your problems.