[asterisk-dev] iLBC codec

[Hans Witvliet]

On Wed, 2011-07-13 at 23:14 +0800, Steve Underwood wrote:

> > Steve Underwood schrieb:
> > [...]

> > We had tested G729 vs iLBC vs G711 directly with Cisco 69xx phones on 
> > a Cisco Callmanager installation. We have let a couple of people 
> > compare the codecs.
> >
> > All persons what have tested have told us that:
> > 1. All of the people told us that G729 sounds worst of all
> > 2. All of the people told us that iLBC sounds good
> > 3. All of the people told us that G711 sounds good
> > 4. Most of the people told us that G711 has the best sound
> > 5. A few people told us that iLBC has the best sound
> >
> > ...
> >
> > So I have a different opinion about iLBC then you. But this is just a 
> > personal opinion :) At least I will always use iLBC instead of G729 
> > where possible.
> You can argue about G.729 and iLBC, but If G.711 wasn't the very very 
> very very clear winner amongst those, I wouldn't trust your testing 
> methods. :-) As long as you filter away anything below about 200Hz, 
> G.711 sounds close to uncompressed 3.5kHz bandwidth audio.
> >

Considering quality against bandwith usage, from the mentioned list
above, G711 should provide best quality. Although not mentioned, perhaps
wide-band codecs might be able yo produce something better. (at a price)

Just one aspect is not considered in the comparison, what is the impact
of latency or loss on the quality? Perhaps some codecs are more
vulnerable than others to not-so-perfect connections...

hw