[LAU] Noob needs help using jack

Mario R. Osorio nimbiotics at gmail.com
Sat Jun 15 19:22:03 UTC 2013


Len,

Thanks a BUNCH for your detailed explanation

I finally could accomplish what I wanted with pulse audio. The only thing I
needed to do was to load the loopback module and voila!

I found the answer on this video: http://www.youtube.com/watch?v=RSeINGM68A8

I went thru at least a dozen tutorials on how to get "stereo mix" in
linux/linux ubuntu, none of them mentioned the need for this step.

I'm also 100% positive I did not have to do so when I acquired "stereo mix"
in my ubuntu 10.04 box.

Anyways, it worked. Its not perfect, but we can live with that.

I will, nevertheless, follow your explanation because I guess I will get
better quality.

Not today though; I've had enough. my brain is burned. I dont mind trying,
but trying without knowing is like trying to walk in a dark room; you just
stumble again and again.

I will start jack again tomorrow. Today I need some scotch, rick wakeman &
urban terror.

One more time MUCHAS GRACIAS LEN!


Dtb/Gby
=======
Mario R. Osorio
"... Begin with the end in mind ..."
http://www.google.com/profiles/nimbiotics


On Sat, Jun 15, 2013 at 2:27 PM, Len Ovens <len at ovenwerks.net> wrote:

>
> On Sat, June 15, 2013 9:32 am, Mario R. Osorio wrote:
> > First of all, I'm a complete noob and might need help in more than one
> > way.
> >
> > I am helping someone who is conducting a research.
> >
> > For this, she will be making dozens of phone interviews, for which I'm
> > using google voice.
>
> Be aware that the google voice (assuming the same technology as the gmail
> phone app) has higher latency than some of the others (including skype).
>
> > She needs to play sounds to the guests/interviewed persons (using vlc or
> > audacious) and I need to record everything that is going on; the
> > conversation and the playback.
>
> I think a mix of idjc, jackdbus and pulse (with the jack-pulse bridge
> module installed) should work. Please note that because of the multiple
> codecs running at the same time, you need a modern machine. I have managed
> to get this to work using my ten year old P4, but it was just barely and I
> had to play with the latency of jack to balance performance with working
> at all. idjc has it's own audio file player built in and I would use that
> instead of vlc or audacious as they do (at least audacious does) strange
> things when set to jack as an output :)
>
> I am not sure which version of ubuntustudio you have. There have been
> issues with the pa-jack bridging in the past and there are some features
> available now which were not a few versions ago. One of the important ones
> is that pa used to bridge as many lines as the audio interface would
> handle... 10 ins and outs in my case which used much more CPU than just
> the two lines I needed :)
>
> basic workflow:
>
> browser with google voice, talks to pulse. Pulse is bridged to jack, two
> lines each way, and set to not auto connect (auto connect is to audio
> playback/capture)
>
> idjc has a port called phone in out (connect to pulse) as well as local
> mics from the sound card. They would all be connected using the
> connections pannel in qjackctl for example. Once you have it figured out
> save it as a session. Set idjc not to stream, but to record.
>
> The order of running things is important:
> -pulse runs at login.
> -start jackdbus with qjackctl and confirm that the pulse ports show up.
>    (in qjackctl connections)
> -in pavucontrol, set the default output to jacksink and the default
> capture (input) to jack source. (green check box)
> -start idjc.
> -Connect the pulse ports to the idjc phone ports.
> -Connect mics as needed (idjc allows you set up however many mic or stereo
> inputs as you need)
>    (this would be the place to create a session. in qjackctl the
>     patchbay would be the place for this)
> -make your google voice connection and verify all the sound goes both
> ways. (If the person on the other end of the line can't hear the audio
> playback from the file player you may have to connect the line back to
> pulse to the program output instead of the phone port.)
> -Set up record and go.
>
> All audio playback should be headphones :)
>
> I would have two computers in the same room and try it all out. The second
> computer would be the remote and so should be able to have any OS on it
> that can handle google voice.
>
> > We might also need to, while recording, play sounds from youtube.
>
> Any youtube audio would get mixed in with the audio coming from your
> remote google voice conversation. Pavucontrol will allow you to control
> the levels of the two signals for balance.
>
> Using just pulse is possible, but less controllable. For that, you just
> need to get familiar with pavucontrol. It's use for these kinds of things
> is not obvious :) The thing to remember is that with PA a connection only
> exists when it is being used. That is Audacity will only have an input to
> connect to when the record button is active... so pause ->record->make
> connections->set levels->release pause to record. Applications made for
> jack (not audacity which has jack as an addon) open a jackport at
> application start and it stays open as long as the application is running.
> Just like in the analogue world where a tape machine always has an input
> plug and the cable that connects to it doesn't move just because you hit
> the stop button.
>
> --
> Len Ovens
> www.OvenWerks.net
>
>
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