64 bit mp3 on Mac?

[Robert Faught]

I am writing a program that runs on Linux, Windows, and Mac. Gstreamer 
works everywhere and gets better and more reliable with each release. 
I'm trying to stay clear of copyright and patent issues.  By limiting 
the number of formats I support to Ogg Vorbis, FLAC, WAV, MP3, Theora 
and Webm I feel that this part of the job is manageable.

MP3 is an unfortunate necessity. On Mac and Windows I avoid distributing 
mp3 codecs by relying on Gstreamer's support for native OS features. I 
don't distribute Gstreamer for Linux, but trust people can use their 
distribution's package manager or build it themselves. I tell them to 
get the free Fluendo codec. All this seems very good, and maybe even legal.

The problem is with the 64 bit version on the Mac. The Quicktime wrapper 
no longer builds because Quicktime API has been replaced by QTKit.  The 
lack of MP3 creates a messy gap that is hard to explain to users and 
looks like a big bug.

What to do?

The Fluendo choice is limited to UNIX platforms (more UNIX than OSX 
anyway). Are there alternative sources for a free licensed codec?

I would like to keep my existing structure as much as possible. Video 
and the other audio formats work just fine on 64 bit Mac and everywhere 
else.

I am not familiar enough with GStreamer or the Mac or ObjectiveC or 
QTKit or mp3 to take on creating a 64 bit replacement for the quicktime 
wrapper right now.

I believe I need to keep GStreamer bound to the 64 bit app because it 
writes video to OpenGL textures. Though it might be possible to make a 
32bit child process to handle audio. It seems like having two GStreamers 
running is asking for trouble. I have not tried this though.

Is there a relatively easy way to decode mp3 using the native API and 
feed it into a GStreamer pipeline (perhaps using appsrc)?

Has anyone else faced this problem?