[Discuss-gnuradio] GR-AUDIO-OSX and GR-AUDIO-PORTAUDIO

[Michael Dickens]

2 items to note:

(1) GR-AUDIO-OSX is available from GR cvs repository (thanks Eric); I  
will add it to the "checkout" script to make it generally available  
to all.  The current version works just fine, but is "no frills"; it  
should bootstrap, configure, compile, and install in whatever "usual"  
manner you use, but do note that it probably requires GNU's LIBTOOL  
v1.5.20 or newer (I'm pretty sure that v1.5.10 failed to compile  
it).  I checked it out and built it this morning from the repository  
and everything is OK (for me).

The primary significant difference between this module and the other  
audio modules is that it uses the default system device for input and  
output, and the user needs to change this device for each use (via  
the Sound preference pane in the System Preferences).  In some future  
version I will work on changing this to a more robust solution.  In  
the mean time, the "--audio-output" or "--audio-input" option for  
most Python scripts (the second option when instantiating the audio  
module) is used instead to specify the maximum number of channels to  
(try to) use (as a string).  See the "README_OSX" in the top  
directory for more info.

I will be making internal changes to parts of GR-AUDIO-OSX as I find  
time; they will make no significant difference in functionality  
(might even reduce latency, if I do some of them correctly).  I will  
also add functionality for the user-default options file when I get a  
chance.  Right now defaults are 44.1 kHz sample rate and 2 channel  
stereo input or output.  For anyone who tries out this module, please  
let me know if you have problems installing or using it, comments,  
suggestions for changes, etc...

(2) the latest PORTAUDIO (V19 from svn as of May 2, revision 996)  
contains updates for proper compilation (again) under OSX.  I've  
installed this version, and then gr-audio-portaudio compiled and  
installed without issues.  Looks like someone rewrote the audio.py  
selector script, and it's really slick (I guess to make use of the  
new user-default options file).  Audio definitely works using  
PORTAUDIO on OSX!  Good to have alternatives.  While PORTAUDIO is  
probably a more "thorough" implementation, GR-AUDIO-OSX has a -lot-  
less latency (as one can hear if you do connect the default input  
audio device to the default output audio device).