VOIP Codecs are those VOIP elements which are utilized in order to convert analog voice signals over to a digitally encoded variant. There are many types of Codecs available today. They vary significantly in bandwidth needed, in sound quality, in the requirements for computations, etc.

What makes codecs so essential to understand is that every phone, VOIP, program, service, or gateway commonly supports a few different versions of codecs. When two different machines communicate together, they have to work out which form of codecs they will utilize.

In principal this sounds like a convoluted mess. In reality, it actually works out most of the time, since two different systems will commonly support at least one codec in common. For example, a Cisco ATA-186 will support these following codecs: G.711a, G.723.1, G.729a, and G.711u. At the same time, a Cisco 7960 machine will support the following codecs: G.711u, G.711a, and G.729a. Therefore, the two machines will decide to communicate in either codec G.711a, in codec G.711u, or in codec G.729a.

While some codecs must have a royalty paid in order for them to be utilized in a program or a product, others are offered royalty free. iLBC is a VOIP codec which was initially developed by Global IP Sound. It has been offered, along with its critical source code, to developers of communications machines under a free and reasonably liberal license, which is still restricted in some respects. It allows permission for the developer to modify it.

This iLBC, which stands for Internet Low Bitrate Codec proves to be a no charge speech codec that is practical for use in vigorous voice communications which take place over IP. The iLBC codec itself permits a more graceful quality of speech degradation when lost frames are present. This happens in correlation to delayed or lost IP data packets.

iLBC has a number of useful features to it. These are listed below, as follows:

• It has a great degree of robustness per packet loss.
• Its base quality is in excess of that provided by G.729A.
• It has a computational complexity which is within the range of G.729A.
• It proves to be a totally free of royalties codec.

There are a number of other VOIP supporting codecs available. The truth is that not many of them that are of high quality are available totally free of royalties. Others will not permit modifications that the designer may deem necessary.