[asterisk-dev] iLBC packet loss concealment
Steve Underwood
steveu at coppice.org
Sun Apr 16 18:37:39 MST 2006
Mike Taht wrote:
>
>
> On 4/16/06, *Steve Underwood* <steveu at coppice.org
> <mailto:steveu at coppice.org>> wrote:
>
> These days, you can achieve far better quality than a normal phone
> call
> at rates much lower than 64kbps.
>
> The main quality issue with normal phone calls is they are limited to
> 4kHz bandwidth. This is insufficient for good quality speech. 8kHz
> bandwidth really improves things. It lets you distinguish things "f"
> from "s", which is almost impossible on a normal phone line. In the
>
>
> This is one reason why good quality, in particular, continuous, voice
> recogition is nearly impossible over POTS. Even with limited domains,
> at 8khz it's all billions of dollars of R&D can do just to
> consistently mis-recognize "T-birds Pizza" in Los Gatos as "P-Birds
> Pizza".
>
> I note that this article on the wiki debunks the ilibc assumption for
> skype and goes into some depth:
>
> http://www.voip-info.org/wiki/view/Wideband+VoIP
I'd debunk the debunking. GIPS have changed the name, but their wideband
codec is basically iLBC stretched to wideband.
>
> I went looking at mattf's asterisk wideband branch - seems out of
> date, is it dead?
> http://svn.digium.com/view/asterisk/team/mattf/asterisk-wideband/
>
> and some interesting old threads...
> http://lists.digium.com/pipermail/asterisk-dev/2005-June/013314.html
> <http://lists.digium.com/pipermail/asterisk-dev/2005-June/013314.html>
Regards,
Steve
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