[maemo-users] kphone on N800

From: Paul Dundas pdundas at btinternet.com
Date: Sun Oct 28 12:05:29 EET 2007
Gopinath Rao Sinniah wrote:
> Hi,
> I've managed to compile kphone VoIP for N800/N770. when I tried to make
> a call, it gives an error message that the sound device is busy.
> I've tried terminating the esd but still the same.
> I've also changed the code and it says wrong channel allocation for the
> pcm device.
> Any suggestion to overcome this problem. Is there a way to use dmix for
> pcm to solve this.

I have no idea really, but was just reading the quick start guide (I was
looking at installing the development environment), and I spotted the
following. It might be relevant.

For audio programming maemo has two main APIs: GStreamer and ESound.
Usually system sounds, such as sounds for notifying user for an event,
e.g. battery low, is played through ESound. More sophisticated
operations, for example playing music files or recording audio, should
be generally done using GStreamer which provides better performance and
a much more flexible API. Most of the maemo’s computing intensive
GStreamer elements are implemented using the device’s DSP which greatly
enhances their performance.

Linux kernel also has two lower level audio interfaces: ALSA and OSS.
>From these ALSA is supported through a plug-in package which is part of
the SDK. The legacy API OSS is not supported by the kernel, but ALSA has
an OSS emulation system, which works for most purposes.

For the audio APIs’ documentation, see the GStreamer web site[23],
ESound white paper[9] and ALSA project’s web site[1]. More in-depth
material is available in the Multimedia Architecture guide[59].

[1] Alsa project’s home page. http://www.alsa-project.org/.
[9] Esound white paper. http://developer.gnome.org/doc/whitepapers/esd/.
[23] Gstreamer project’s home page. http://gstreamer.freedesktop.org/.
[59] Multimedia architecture. http://maemo.org/development/documentation/

Good luck with the hacking - more and better VOIP is needed!


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