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.