There are many different voice codecs in VoIP and IP telephony technologies. Although G.711 and G.729 are generally used among VoIP voice codecs, the use of new codecs has become widespread with the increasing capacity and bandwidth of the devices. Here are examples of common codecs:
- G.711 Variations (most used audio codec)
- G.729 Variations (codec used for low bandwidths)
- G.722 (Broadband audio codec)
- G.723 (A codec using ADPCM with sound quality such as G.711)
- iLBC (a low bandwidth codec)
- iSAC (a broadband codec at WebRTC)
- OPUS (low latency and variable band codec)
- AMR variations (a codec used for speech encoding)
- GSM (the codec used in the simplest term in mobile phones)
Each codec has a different algorithm, so they have different complexity, sound quality, and different bandwidth requirement. In this article, I will not go into the detailed features of codecs one by one (maybe I can examine in more detail in another article), but you can listen to the change of sound related to the use of commonly used codecs in my video which also includes frequency analysis graphs of each codec: