• Registered: 2009-04-05
  • Posts: 12

Topic: Audio Initialization

I'm trying to use btplay from an SSH prompt to play an MP3 file that I have on a flash drive.  I'm using a Botball Chumby; the modified boot script is here: http://forum.chumby.com/viewtopic.php?pid=20937#p20937 .

Unfortunately, btplay does not seem to play the audio, although it clearly thinks it is playing and gives no obvious errors.  I have started btplayd manually, so I know that btplayd is running.

I suspect that the Botball Chumby boot script does not initialize the audio subsystem.  A few weeks ago, I was playing around with the Chumby Control Panel (which does not normally boot on the Botball Chumbys), trying to get a Wi-Fi connection, and at some point while the Control Panel booted, I heard an audible click from the Chumby, and after that point that particular Chumby was able to play audio, even after reboots.  I have since switched Chumbys (I have 2 of them), and I am unable to reproduce that click, nor am I able to get this Chumby to play any audio.

What audio initialization is done by the default Chumby boot scripts, software, and Control Panel, and what shell commands would I have to run to mimic this initialization?

This information is needed as supplementary material for a technical paper I am writing on the Botball Chumby, and that paper is due in 2 days, so I'm hoping someone can help me out quickly.

Thanks!

  • Registered: 2008-06-27
  • Posts: 518

Re: Audio Initialization

Could it be the startup scripts unmuting everything?  I believe the following code, which starts at line 136 of /etc/init.d/rcS, might be what you're looking for:

# set the speaker mute based on previous speaker settings
if [ -e /psp/mute ]; then
    echo -n "Restoring mute setting: "
    chumby_set_volume --master_mute `cat /psp/mute`
fi  

# set the volume
if [ -e /psp/volume ]; then
    echo -n "Restoring volume setting: "
    chumby_set_volume --master_volume `cat /psp/volume`
fi  

# set the speaker panning
if [ -e /psp/pan ]; then
    echo -n "Restoring speaker pan setting: "
    chumby_set_volume --master_panning `cat /psp/pan`
fi

3 Reply by biolizard89 (edited by biolizard89 2009-06-14 21:14:55)

  • Registered: 2009-04-05
  • Posts: 12

Re: Audio Initialization

Hi ChumbyLurker, thanks for the info.  I have tried this, and still no luck.  The volume files in /proc also appear to be fine.  I assume that if mute is set to 0, that means sound is enabled?  If so, then I'm clueless, as all of the mute files seem to be 0.

Any ideas?  Thanks.

EDIT: It seems the hpin file is set to 1, meaning that the Botball Chumbys have something plugged into the Chumby headphone port.  Not sure if this is relevant, but I thought I'd mention it in case this helps someone diagnose my problem.  Thanks.