Re: Amateur Radio -> MacOS?

[Stelios Bounanos <lhams@enotty.net>]

>>>>> On Thu, 31 Jan 2008 23:10:01 +0100, Stephane Fillod
>>>>> <f8cfe@free.fr> was rumoured to have said:

> Tomi Manninen skribis:
>> Frank Brickle wrote:
>> 
>>> Applications that use JACK move smoothly between Linux and OSX. They can 
>>> also take good advantage of FireWire sound systems like the Edirol FA-66.  
>>> Please see http://dttsp.org/wiki for an example of an SDR application that 
>>> runs on Linux and OSX without pain.
>> 
>> Yes, but IIRC, Jack is also callback based *) and that is the key in my
>> argument. Doable but non-trivial changes are needed. That requires
>> someone with the motivation and hardware to do it.
>> 
>> This is not meant to be an excuse why ham radio software is lacking
>> from OSX (and I don't even know if it really is), just a possible
>> explanation why at least some soundcard based Linux ham radio programs
>> are not trivial to port to OSX.

> What about Libjackasyn[1] and jacklaunch?
> Does PortAudio[2], which is also callback based, have a similar library?

IMO, PortAudio would be a much better option.

PortAudio is callback-based but, in v19, also has a blocking API.
Fldigi uses it and is able to access OSS, ALSA, and JACK. I understand
that PortAudio also supports the OSX sound system (CoreAudio?).

JACK support is a big bonus because it makes fldigi usable with DttSP[0]
and, to a lesser extent, because it makes it easy to run multiple
instances (to decode more than one signal at the same time and test /
experiment).

The move from OSS to blocking PortAudio was fairly straightforward in
fldigi and I would expect this to be the case for gMFSK also.

There are a couple of things to look out for. First, some sound system
features have been placed in PortAudio's "Host API extensions" in such a
way that they are actually unusable with dynamic linking. This has not
been a problem for fldigi, as there was no need to use those extensions
(though setting the JACK client name would be nice).

Second, the OSS style of opening/closing the device for capture/playback
works fine but has an undesirable side effect with Portaudio/JACK
streams -- the port bindings are reset.


[0] http://dttsp.org/wiki/index.php?title=Main_Page


73,
Stelios M0GLD.

-- 

Stelios Bounanos
perl -e 'print+reverse"t\nney.ttno\@esb"=~/(..)/sg'     #key: 0xE88A7F61