Jack audioserver on Pandora


mcobit

Advanced Member
Joined
Jul 28, 2008
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Anyone got a working version of jackd running on Pandora?


I would like to try some programs like http://freewheeling.sourceforge.net/ as i think the Pandora would be a great mobile loopingstation for beatboxing and loopperformances with some instruments.


I can compile free wheeling without a problem, but it complains about the jack server not being started. I can't start it though as it says something about invalid configurations.


The toolchain seems to have the headers in it, as it detects jack at configure stage.


I also tried to install jack-server with opkg, but that doesn't seem to solve the problem with bad configuration either.


Anyone has an idea?
 
I am just installing slack, and hope it will work this time, but I'd like to put it in a pnd, so I think I will have to supply the complete jackserver with the pnd. Oh well...
 
Jack (like timidity) is so critical with many audio apps, why not make a standalone version ?
 
I could try, but I don't know if it will work out.


I got jack compiled with qjackctl under slackware, as well as the program and fluidsynth, but I can't start it with alsa support, as the driver cannot be loaded. Also I don't get realtime priviledges. Not even when Using the rt-kernel or as root.


Jack can be started with oss backend and without realtime, but then I don't get the mic as input nor can I hear any sound when I connect fluidsynth to the outputs and playback a midifile.


I'll see, if ai can figure something out this evening. If anyone is experienced with jack and wants to try, please help me :)
 
Jack needs to be configured for jack-alsa, and will probably need to 'take over' linux audio while running, which means kill whatever is running on Pandora (wtf, I forgot: is it plain ol' ALSA or OSS on PandoraOS?) and then let Jack be the main audio routing option.


Then, set up alsa loopback devices so that any ALSA-needing applications can still have them, albeit with jackd doing the dirty work.


Probably there is something specific with the Pandora Audio devices configuration, also, that is not 'automatically figure-outable' by jackd; I am afraid I'm not much help without my Pandoras in front of me (left 'em at the office), but I seem to recall there were not just the standard hw:0 devices, but others too. Jackd needs to be told what they are, specifically.
 
Plain ALSA i think.


I'm gonna rebuild an new rt-kernel based on the latest OP git, with all cleanups from Notaz.
 
I have no clue what they all are. There is hw:0, /dev/dsp, /dev/audio, someotherhw:0, etc. None of them seem to be the microphone for example. I just got one stereo input and output.


I think it was some alsa on top of oss or oss emulation. Alsaconf for example doesn't find a soundcard at all.


Edit: Maybe I should add, that I don't have a lot of experience with audiostuff on linux, so every help is appreciated :)
 
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No oss. Alsa oss-compat.


Alsaconf may not report a card although there's one present.


Usually hw:0,0 is the output, and hw:0,1 the input.
 
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I'm currently compiling the new rt-kernel.


This time the patch perfectly match our latest kernel ^^.
 
Btw, is there a realtime group set up for users, who want to use the realtimefunctions?


I tried to add my user to the audio and realtimegroup but wasn't able to use the rt functions. At least jack said so.
 
Great! But not with the internal soundcard? I need to get that kernel and try again.


Thanks for your effort!
 
Yup seems there's a problem somewhere with the internal audio :/


I must have been wrong when i said i did RT before.
 
Used jack2, they have a bugfix for ARM and it runs great!

(something with 'alignment trap')

I have tried different settings but I got performance down to 21.3msec latency.

This with:

  • Frames/Period: 256
  • Sample Rate: 48000
  • Periods/Buffer: 4
Theoretically it should be able to go lower, but we need to find the best settings.
 
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Dos this mean, Rackarack for Playing Elekrik Guitar and Bass via a Audiointerface like the Rocksmith Cable could be Real??
This would be awesome..
 
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