VoIP Codecs and Quality
About VoIP Codecs
VoIP codecs are standards which are used to render voice data into the 1s and 0s which travel over the network. Unlike regular analog encoding for phone calls, VoIP has to push data using TCP IP which sends information in packets and consists of discrete bits of information.
Converting voice data into digital format in itself isn't a very difficult job. What's difficult is trying to determine which technique is best and then getting everyone to agree to use the same codec. This is important because without such co operation two systems can't communicate with one another. In this article, we're going to take a quick look at how codecs affect VoIP quality, how there's always a trade off between quality and bandwidth and look at a few examples of VoIP codecs as well.
The trade off between quality and bandwidth is easy to understand. The more clear a voice signal is, the more information it has to carry to maintain that quality and therefore uses up more of your Internet than a signal like the one on a PSTN phone.
Choosing a VoIP Codec
The process of settling on which VoIP codec to use depends on the architecture and the setup. If you're making VoIP calls using a software like Skype, you're automatically using the proprietary Skype protocol. From what we know, this protocol adapts itself to the bandwidth and increases or decreases the compression accordingly.
If you're using a hosted PBX setup which relies on the SIP protocol, then the two sides will have to negotiate a codec before the call can go ahead. This negotiation takes place depending on a variety of factors. It's important to note that if the call is to a regular PSTN line, there's no point in having anything higher than a standard G.711 codec since the signal will have to travel over the analog phone lines anyway.
But when both end points are VoIP, have a decent bandwidth and are HD Voice phone systems, we can select a codec that delivers excellent voice quality incorporating all the higher harmonics of the sound. The final experience is much more life like and it greatly eases communication especially in conferencing scenarios.
VoIP PBX systems running on SIP are currently the most flexible and easy solutions for a business. Hosted solutions allow you to focus on what is important to you and leave the complex VoIP infrastructure maintenance and upgrades to the professionals.