Flash CS4 (10.0.2) on Mac...
I'm experiencing a very frustrating problem when publishing movies that contain audio set to export to MP3. Certain high-frequency transients (for example "S" sounds in voice recordings) in the audio tend to howl or screech during playback.
My typical audio workflow is to import AIFF audio (stereo, 44.1 khz, 24-bit) files created in Logic Pro, then publish the SWFs with all sounds set to MP3 compression, 64kb/sec, stereo, "best" quality.
This is an intermittent problem, but it seems to have gotten worse with the 10.2 upgrade. Often I have to publish over and over, especially if I have a movie with lots of sounds (games are a nightmare) to get a clean SWF where none of the sounds howl. Quitting and relaunching Flash seems to have no effect.
The attached tests were published from the same Flash file, literally one right after the other.
BTW, this problem has been around a loooong time - since Flash 8 at least. Is it a Mac thing?
When you try changing the publish setting to 128 kbps instead of 64, what happens? Does the howling sound get worse or better?