text: I have an Actionscript routine that works off sound time to control stopping, starting, and scrubbing to parts of a movie. It works fine when I'm able to "use imported MP3 quality" in the Sound properties panel. It messes up when not.
  I've read other posts about making sure the imported MP3 format has a sample rate that is a multiple of 11 khz. Also that the file should not have metadata. So I'm using Sound Forge Audio Studio to output 44,100 KHz, 16-bit, mono files with no metatdata.
  The vexing part of this is it works with some files and not others that were output with the same settings. Flash is fickle. It just decides one file can be used as is and other not...
  I'm wasting a lot of time here trying to solve this. I'd appreciate any help.
  I just tried importing the MP3 into a new Flash doc and it displayed the "use imported MP3 quality" checkbox.
  So it wasn't the MP3 file afterall - once again, and once too often, the problem is in Flash. I had used a copy of another Flash doc as a base for the one I was having the problem with. For some mysterious reason it's not treating the imported MP3 as a new Flash doc would.
  If I had $5 for every hour I wasted due to Flash bugs, crappy documentation, and lack of support I could take a nice long vacation.
  Class action suit anyone?
  Make sure that the mp3 file doesn't have album art and any other metadata. I had the same issue, but after removing the album art and metadata it worked fine.
  peace.
  Still having intermittant problem with Flash not allowing "use imported MP3 quality". It should and does allow it when the file is 44K 16 mono (my preferred setting for this app) but occasionally, mysteriously, it doesn't.
  I find that after powering my computer down (not just restarting), then booting up and launching Flash again takes care of the problem. WTF!
  My only guess is that Flash must keep some kind of cache open on authoring sessions and something gets corrupted after a time. I don't know - there must be some explanation for it.
  yeah, I'm still having the issue. It happens for 80kps mp3 files, but not for others. it doesn't make sense.
  now it's happening to other non 80kps files. I have files that are all encoded the same, some work, some don't. Hello Adobe, this has been an issue for over a year, what gives?
  This is definitely a bug in Flash. After many tries this is what I found:
  MP3 files must be 44,100 KHz (or any multiple of 11 Khz - so the forums
  say)
  1. If your file is 44,100 KHz and you do not get "use imported MP3 quality"
  on the imported file, the problem might be some corruption of the Flash
  file. This might happen when using an existing movie as a base for a new
  movie. Delete the old sound file from the Library. Open a new Flash doc and
  import the MP3 and then copy and paste it into the problem doc.
  2. If that doesn't work, I've found - inexplicably - that exiting Flash and
  shutting down your computer (power it off, not just reboot) and try
  reimporing again and it should work (does for me every time). It must be
  something to do with Flash memory cache - maybe it gets corrupted and
  shutting down flushes it, I don't know.
  Once you do this Flash will be OK for future sound imports - but it seesm
  that after a while (hours working) the problem repeats and you have to apply
  the above prescription.
  Thanks raylaur, but both of those didn't work for me.
  If this has been answered, what was the answer?
  The 'answer' for me is to export the files as a Quicktime movie and use FLVplayback component for controls. I had problems scrubbing the movie (with my Actionscript scrubber) when the file did not import as 'use MP3 Quality'. I still save sound files as 44,100 KH and have no problem synching the sound.
  Yes, well, saving the audio uncompressed and then performing the compression within Flash is of course a way around the problem, but I'm not sure it's an 'answer' to the problem...
  10 years on, I'm wondering if this has been resolved? I am trying to bypass the compression in Flash. I have an audio file that sounds ok in the 'test audio' but when I test movie it sounds terrible. I have gone through the settings on compression - default seems to be the best - but it still compresses, seems like 41,000 compresses to 44. I want no compression - is this possible.
  I don't import audio in an FLA any longer, too many issues. I now embed them via ActionScript. I've found it to be much more useful. I can easily update my mp3 files without having to create a new swf. Although, the Flash Player wont seamlessly loop an embed mp3 (or a loaded mp3 into an FLA). So for music loops, I have a swf just for those and let Flash compress those mp3 from AIFF or WAV. Then I link the Music Loop SWF in the FLA's library. Then embed that SWF and access the sound's Class.
  Here's info about embedding sounds. ashdevelop.html