[pulseaudio-discuss] PulseAudio / Jack main purposes in life?
Bill Turner, WB4ALM
wb4alm at arrl.net
Wed Mar 20 10:12:51 PDT 2013
Len, thank you very much for the quick review / definition...
If Jack is a "one card" solution, then it will not meet my needs - and
in fact, none of the applications I wish to use know anything about Jack.
As a retiree, now on a fixed income budget, I doubt that I could afford
a multi-channel audio card. If, however, you would like to mention a
name or two, it would be appreciated.
My biggest problem is that I have lots of separate audio, and a lot of
audio to be kept separated...
At this point in time, the majority of the applications are, in effect,
With one major exception, most of the applications that I use, do not
provide any choices as to selection of the sound card. The majority
assume that they have exclusive use of the system default sound card.
FLDIGI is a major exception to this. It allows configuration for the use
of (1) OSS, (2) PortAudio, (3) PulseAudio, and if you are using OSS or
PortAudio then you have control over the Linux device name, or the sound
card name and the ports that you wish to use. If you are using
PulseAudio, then you can specify the name of a remote server.
My initial tests indicated that PulseAudio was intended to mix whatever
sources were not "muted" into a single "output", which then caused
system sounds, etc to appear in the audio stream being sent to my
primary speakers and the application being run. This is why I asked my
original question the way that I did -- and your response seems to
confirm that PulseAudio is a single "studio" control and not a "Master
Control" for a bunch of different studios.
As a result, I have told PulseAudio "hands off" for two of my audio
cards, and I use the PortAudio feature of FLDIGI on two separate
instances to allow each instance to control a separate sound card (which
in turn are connected to two different radios).
My fear is that "PortAudio" might cease to exist (or be supported by the
application or the Operating System) and then I would be out on a limb
with no place to go.
- - -
So I believe that I need a program or group of programs that can handle
multiple audio cards. Some of these cards will be connected via USB, so
IRQ conflicts should not be a major issue.The majority of the audio
being processed will generally be between 300 and 3000 Hz.
One of my internal cards is a PCI "sound blaster" card, because a few
special purpose programs that I have make use of some of the on-board
hardware features of that card.
Since the programs that use the SB card are also used in two-way radio
communications, absolutely NO unauthorised or unexpected audio can be
inserted into an outbound signal, such as system sounds, music, etc.
Having something like PulseAudio control the SB card is feasible, as it
is unlikely that PulseAudio would try to connect to ALL of the on-board
SB card features. (Feasible, that is, as long as PulseAudio did not try
to mix the audio with other audio streams before presenting it to the
I also have a special purpose external USB connected sound card
(SignaLink USB) that is used to process audio to and from one of my
transceivers. It must also be segregated from system sounds or other
audio sources. (The input and output audio channels could be mixed into
other streams for monitoring purposes, as long as the monitoring is
volume controlled and/or mutable.)
Some programs that I use, such as QSSTV, only allow audio to and from
the default audio card. No other options are provided by the author.
I would assume it uses OSS or ALSA, since the author makes no mention
Ideally, I'd love to have something like PulseAudio control all of the
sound cards, and then provide addressable in/out ports (or channels),
that could then be independently connected to the appropriate
applications. It would also be VERY nice, if channel inputs and outputs
could be dynamically configured.
It doesn't really matter that current GUI's don't make independent
control easy or not - and assuming that PulseAudio uses a config file,
as I could then create a script or two to reconfigure PulseAudio on an
as-needed basis. This is assuming, of course, that there is documention
available. I am a retired programmer, so I could learn "C" if necessary.
Even the problem with QSSTV could be eliminated, again assuming that
some sort of "dummy default" definition could be established within
- - - -
As an aside, I multitask when sitting at my computer, as I might be
browsing or creating documentation and/or web pages; writing a program;
conducting a keyboard conversation over the air; or participating in a
controlled Radio Net.
This could be occurring while waiting for information and pictures to
finish "downloading" from the Internet or from one of my radios.
I might even be "listening" to a commercial Television or Radio Stations
or a Weather Service.
"Lots of separate audio, and a lot of audio to be kept separated."
Again Len, thanks for sharing...
/s/ Bill Turner, wb4alm
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