Completely understandable my suggestions were a bit less of what you
should do and more of what should be done for integration into trunk.
 Your code works well, obviously accomplishes what you need, and
doesn't break existing stuff all which are good.  The downside is
anyone trying to understand portaudio and use portaudio now has two
very different interfaces for doing so depending on what they want to
do.   In addition any code that wants to take advantage of
multi-channel portaudio has to be rewritten.