There are many codecs for audio, video, fax and text. Below is a list of the most common codecs for VoIP. As a user, you may think that you have little to do with what these are, but it is always good to know a minimum about these, since you might have to make decisions one day relating codecs concerning VoIP in your business; or at least might one day understand some words in the Greek VoIP people speak! I won’t drag you into all the technicalities of codecs, but will just mention them.
If you are a techie and want to know more about each one of these codecs in detail, have a look there.
Common VoIP Codecs
| Codec | Bandwidth/kbps | Comments |
| G.711 | 64 | Delivers precise speech transmission. Very low processor requirements. Needs at least 128 kbps for two-way. |
| G.722 | 48/56/64 | Adapts to varying compressions and bandwidth is conserved with network congestion. |
| G.723.1 | 5.3/6.3 | High compression with high quality audio. Can use with dial-up. Lot of processor power. |
| G.726 | 16/24/32/40 | An improved version of G.721 and G.723 (different from G.723.1) |
| G.729 | 8 | Excellent bandwidth utilization. Error tolerant. License required. |
| GSM | 13 | High compression ratio. Free and available in many hardware and software platforms. Same encoding is used in GSM cellphones (improved versions are often used nowadays). |
| iLBC | 15 | Robust to packet loss. Free |
| Speex | 2.15 / 44 | Minimizes bandwidth usage by using variable bit rate. |
