VoIP/Mobile Codecs (was Re: Operation Ghost Click)

Wed May 2 21:40:02 UTC 2012

On May 2, 2012, at 16:10, Jeroen van Aart wrote:

> Technical specs aside I believe you are mistaken with regards to the actual every day reality. My experience (and anyone else I talked to) calling to and from mobile phones has been 100% a bad one with regards to audio quality. I know the bandwidth allows for better quality, but carriers don't do it, they do the opposite.
> 
> Why else would a mobile phone carrier feel the need to advertise an "HD" (shouldn't it be "HIFI"?) quality line (i.e. a quality that's standard with every land line and already suboptimal):
> 
> http://www.pcmag.com/article2/0,2817,2402598,00.asp
> 
> "Sprint Brings HD Voice Calls to U.S."

Originally, you said VoIP and cellular used bad codecs.  I responded that any decent VoIP provider supports codecs equaling or beating landlines.  I didn't say anything about cellular.  A G.711 call over a solid internet connection will sound entirely identical to any landline telephone call that leaves the local analog facilities and a G.722 call will make G.711 and thus landlines sound like cellular by comparison.

The cellular world works with less bandwidth and more loss than the VoIP world usually deals with, so while us VoIP guys sometimes use their codecs (GSM for example) they don't tend to bother with ours.  That said, the article you link is talking about the same sort of improvements by doubling the sampling rate, so the end result is similar.
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Sean Harlow
sean at seanharlow.info