Re: [Linphone-users] libosip

[Ged Haywood]

Hi Simon,

On Wed, 12 Nov 2003, Simon MORLAT wrote:

> >>You need to choose the alsa card id (not /dev/dsp) in the sound card 
> >>selection combo box of linphone's property box.
> >
> >This was using linphonec.
> >  
> So if linphone was compiled against asoundlib (alsa-lib), you should put
> [sound]
> dev_id=1

I had dev_id=0 so I changed it to =1 with no noticeable difference, so
I recompiled with --enable-alsa, and things improved markedly.  I can
now listen to the remote sipomatic just fine.  I'm still have problems
which are almost certainly caused by the remote system using OSS, so I
must upgrade that system before I can do anything else.  That won't be
for a couple of weeks.

> When invoking linphonec on my computer:
> 
>  >/usr/bin/linphonec -d
> INFO: no logfile, logging to stdout
> MediaStreamer-Message: Found /dev/dsp.
> MediaStreamer-Message: Found ALSA device: Intel 82801AA-ICH
> 
> Command ?

And on mine:

hurricane:~$ >>> linphonec -d
INFO: no logfile, logging to stdout
MediaStreamer-Message: Found /dev/dsp.
MediaStreamer-Message: Found ALSA device: VIA 8235

(process:1776): MediaStreamer-WARNING **: oss_card_probe: can't open /dev/dsp1: 
No such device.

(process:1776): LinphoneCore-WARNING **: General level is quite low (0). 
Linphone rises it up for you.

Command ?

> If you only have one sound card driven by alsa, dev_id=0 refers to
> the oss emulation one (/dev/dsp), and dev_id=1 refers to the alsa
> native mode.

I didn't know that.  I have only the motherboard sound chip on my
desktop machine.

Is there some documentation somewhere that you can point me to which
explains the structure of all this sound system stuff at a high level?
I keep finding howtos and odd bits of documentation here and there but
none of it seems to start at the beginning and tell you what on earth
is supposed to be going on.  It's terribly confusing.  I have no idea
what all the devices are, nor what they're capable of doing, nor how
to use them - nor even how to find out if they're there, or working,
or which parts talk to which, or what settings they may have to offer,
or what those settings are set to.  For example I see talk about a
'mixer'.  It seems I must have set the mixer's volume (or something
like that) to a non-zero value, because I have some sound, but I have
no idea what this mixer is nor where it is nor what it's for.

The fact that any of this stuff is working at all is the result of
sheer determination.  I don't know how I got it to work, I just kept
on working at it, reading more pieces of hap-hazard documentation and
out of date documenation, trying things until some sounds came out.
Then when I switched to use ALSA with linphone instead of OSS I had to
go through the whole process all over again - quicker this time but
almost as painful.

The trouble as far as linphone is concerned is that I might have just
given up, yet none of this is really linphone's fault at all - your
software just happens to rely on some *very* badly documented systems
for its operation.

73,
Ged.