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neok

Member

From: Cyprus

Registered: 2003-12-14

Posts: 190

Website

Please help with programming in ALSA

Hi,

I am trying to make the configuration of some sound applications I have written easier, but I am getting lost in the very sparse documentation of the ALSA API. What I am trying to do is to get my apps (for ham radio digital modes) to set up the sound card for capture, but I just can't figure out what mixer functions to use to specify capture source.  amixer gives me the following info on the capture source I want to use:

Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 46
  Front Left: Capture 46 [100%] [30.00dB] [on]
  Front Right: Capture 46 [100%] [30.00dB] [on]

Simple mixer control 'Input Source',0
  Capabilities: cenum
  Items: 'Rear Mic' 'Front Mic' 'Line'
  Item0: 'Rear Mic'

My problem is how to specify 'Capture'/'Input Source'/'Line' as the input source of the audio from the receiver, so that the signal can be decoded. I have code to specify 'Capture' as the capture source, but how to I select 'Input Source'/'Line' specifically? So far I use xfce4-mixer to do this, but trying to understand its source code is as hard as understanding the ALSA API.

Any hints gretefully welcome ......

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Regards

Neoklis ... Ham Radio Call: 5B4AZ