How to use the /dev/mixer on the Neo

Pranav Desai pranavadesai at gmail.com
Sun May 4 01:05:08 CEST 2008


Hello,

I am trying to port one voice recog. application I found on the internet
which uses the mic to record the voice. It works fine on my desktop, but on
the Neo it cant seem to get the mic device.

Here is a part of the code.

 dev_mixer = "/dev/mixer";

  if ((fd = open(dev_mixer, O_RDWR, 0)) == -1)
    return(MIXER_ERR);

  /***** check whether mic and igain devices available */

  if (ioctl(fd, SOUND_MIXER_READ_DEVMASK, &mask_mixer) == -1)
    return(MIXER_ERR);

  if (!(mask_mixer & SOUND_MASK_MIC))
    return(MIXER_ERR);


But the MIC seems unavailable i.e. it returns after the above statement. So
is the code using the wrong MASK, wrong device or is there something else
wrong.

I tried some other program which list the capabilities of the mixer. Below
is the output of that program. Which also says that mic is no available. It
does show 2 PCMs, so I am not sure what should be used. I can attach the src
if someone is interested.


Status of /dev/mixer:

Mixer      Device     Recording  Active     Stereo     Current
Channel    Available  Source     Source     Device     Level
---------  ---------  ---------  --------   ---------  ---------
 0 Vol      no         no         no         no
 1 Bass     no         no         no         no
 2 Trebl    no         no         no         no
 3 Synth    no         no         no         no
 4 Pcm      yes        no         no         yes        90% 90%
 5 Spkr     no         no         no         no
 6 Line     no         no         no         no
 7 Mic      no         no         no         no
 8 CD       no         no         no         no
 9 Mix      no         no         no         no
10 Pcm2     yes        no         no         yes        100% 100%
11 Rec      no         no         no         no
12 IGain    yes        no         no         yes        0% 0%
13 OGain    no         no         no         no
14 Line1    no         no         no         no
15 Line2    no         no         no         no



Thanks for any help I can get.

-- Pranav
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