[pjsip] Poor Voice Quality on Windows Mobile 6 (with Codecsother than G711)

girish_kumar girish_kumar at infosys.com
Fri Apr 25 02:47:08 EDT 2008


Thanks Benny, I will try to use latest SVN version which has WSOLA disabled to see if at least GSM works fine.

As I understand, PJSIP is using Speex 1.2 Beta 1 version. Is there any work going on for incorporating latest version 1.2 Beta 3 of Speex into PJSIP which may give much better performance as the basic Speex Codec library has been separated out of non-codec components and can be built without Floating point support. FPU is missing in Win CE which may have been a significant factor in its poor performance on mobile.

~Girish

-----Original Message-----
From: pjsip-bounces at lists.pjsip.org [mailto:pjsip-bounces at lists.pjsip.org] On Behalf Of Benny Prijono
Sent: Thursday, April 24, 2008 6:09 PM
To: pjsip list
Subject: Re: [pjsip] Poor Voice Quality on Windows Mobile 6 (with Codecsother than G711)

On Thu, Apr 24, 2008 at 10:43 AM, girish_kumar <girish_kumar at infosys.com> wrote:
>
>
> Hi,
>
> We have built PJSIP for wince platform and deployed it on to Windows Mobile
> 6 based device without exploring any media optimizations.
>
> The Voice quality is fine with both variants of G.711 codec and CPU
> utilization is observed at around 50%. However, if try to use iLBC or Speex
> (Narrow-band) codecs, the voice quality drops drastically to an
> unrecognizable level and CPU utilization shoots into 90-100% range.
>

Hi Girish,

the CPU usage for G711 looks too much, it shouldn't be that high for
G711 IMO. If you're using relatively latest SVN version (the one with
WSOLA in it), please update again to the very latest SVN version. In
current SVN, WSOLA is disabled on both WinCE and Symbian (via
config_site_sample.h) since it seems that it's a bit too much for
these devices.

Having said that, I've never heard people successfully use Speex on
PDA/mobile devices. IMO Speex is just too demanding for these devices.
And probably iLBC is too. But GSM should work, and if you can afford
the bandwidth, G.722.


>
> Has anyone used PJSIP on Windows Mobile 6 and can verify if these
> observations on Voice quality are justified? Please suggest some
> optimizations to improve the quality of voice.
>
>
> Also, the Echo Cancellation is resulting in Jittery Voice (for G.711 codec)
> while Echo Suppression works fine. Any suggestions.
>

The EC is probably too much for mobile devices too, hence it's
disabled by default.

Cheers
 Benny


>
> Thanks
>
> Girish
>
>
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