VoIP compression and codecs

Unanswered Question
Dec 27th, 2009

I have read that the VoIP services offered by some ISPs have a bandwidth of about 24kbps. This is the actual throughput available by the use of the codec G.729.

I want to know of ways to use only use a bandwidth of 8 to 12kbps.

What codecs can I use?  (e.g. G.723.1 ?)

And will I also need to use additional compression techniques?

The header size of each IP frame is also quite large. How can this be controlled or compressed?

I have a feeling that a bandwidth of 10kbps is very narrow and might result in poor voice quality. However, some ISP have found ways of getting around the problem. I would like to have your ideas and knowledge on this.


I have this problem too.
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Paolo Bevilacqua Mon, 12/28/2009 - 00:40

Go to a router, type codec ? in voip DP config mode and you will see a list of what codecs are supported.

Then you can use any search engine to learn about the specific of each one.

Today the most advanced is iLBC. It is not possible to compress further or optimize anything else despite whatever claim done for marketing purpose.


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