Ioana Ivan wrote:
Hi,
We've been trying to write an implementation of
javax.sound.sampled.Mixer(and the associated classes: SourceDataLine,
TargetDataLine, Clip, and Port) that uses pulseaudio as a backend. So
far, SourceDataLine, TargetDataLine and Clip are working (somewhat,
there are still issues that need to be fixed), but we're not sure how to
approach Port.
From the java API:
"Ports are simple lines for input or output of audio to or from audio
devices. Common examples of ports that act as source lines (mixer
inputs) include the microphone, line input, and CD-ROM drive. Ports that
act as target lines (mixer outputs) include the speaker, headphone, and
line output. You can access port using a Port.Info object."
Ports should have an open() and close() method, and ideally they should
also support volume and mute controls. There currently is an
implementation of Port in openjdk that uses alsa to enumerate the
devices that could connect to the sound system, and implement the
required methods.
We were wondering whether there's anything in the pulseaudio API that
could be used to do something similar, and, if not, how problematic
using the old version of Port(that uses alsa directly) with our mixer
that uses pulseaudio is.
I spoke to you on the mailing list but this is a little clearer I think.
Basically you just want to expose the volume of the various Sinks and
Sources here. I would just get a list of all the Sinks and provide
playback Ports that allow volume control and muting etc. and do a
similar exposure for the Sources.
I'd use the introspection stuff to do this (tho' not overly sure).
http://0pointer.de/lennart/projects/pulseaudio/doxygen/introspect_8h.html
You can probably use the source of pavucontrol to work out what to do here.
You can of course export a volume on a "per stream" basis, but I'd
imagine this doesn't map too well to the Java API seeing as streams will
come and go quickly but sinks/sources will be slightly more long term
(tho can still come and go (e.g. when a usb audio device is plugged in
or a network sink is detected etc.)
I think whatever is in the "Output devices" and "Input devices" tab in
pavucontrol (from git) is probably what you want...
HTHs
Col
--
Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/
Day Job:
Tribalogic Limited [http://www.tribalogic.net/]
Open Source:
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Trac Hacker [http://trac.edgewall.org/]
