Mono (one channel) output from .flac to .m4a

What steps will reproduce the problem?
1. Record a session from Mumble. Mumble does positional audio support for voice 
while playing games as a group; if your co-player is on your left, you hear in 
the left headphone. Mumble records .flac. 
2. Convert the .flac to apple lossless .m4a.
3. Output file has one audio channel, and loses all positional information.

How about the reproducibility (always, sometimes, rarely, ...)?
Seems to be always.

What is the expected output? What do you see instead?
Expected output: stereo audio.
What do I see: Mono audio.

What version of the product are you using? On what operating system?
Version: Version 20130127 (142.3)
System: 10.7.5

Please provide any additional information below.

Original issue reported on code.google.com by keybou...@gmail.com on 23 Mar 2013 at 1:36

MarrySunshine / xld

Mono (one channel) output from .flac to .m4a #164