While using VoIP application to call someone, the analog audio signal generated by the microphone cannot be sent over the Internet directly and needs to be digitized and compressed before it can be sent over the Internet.
The mathematical models enable the coding and compression of such analog audio signal which is referred to as "Codecs". Originally, the term CODEC referred to a COder/DECoder: a device that converts between analog and digital. Now, the term seems to relate more to COmpression/DECompression.
One of the important features of a codec is its bitrate, which refers to the number of bits that are required to be transmitted per second. The higher the bitrate the higher is the bandwidth requirement, so the purpose of the various codecs is to strike a balance between efficiency and quality.
The list of Codecs that are supported with VoIP feature in Kayako Desktop application is the following:
G.711 family codec (PCMA, PCMU), Speex/8000 (narrowband), Speex/16000 (wideband), and Speex/32000 (ultra-wideband) with fix bit rate and adjustable quality/complexity settings. Fixed mode implementation will be used for targets which lack floating point unit.
iLBC in 20 or 30ms mode, with encoder mode, is adjusted based on remote's SDP (decoder mode is adjustable during initialization only).
GSM, G.722, G.722.1, and G.722.1C licensed from Polycom. More codecs provided by Intel IPP: G.723.1, G.726, G.728, G.729A, AMR, and AMR-WB. The codecs provided by Nokia APS/VAS on Nokia handsets: AMR, G.729, iLBC, and PCMU/PCMA, L16 family of codecs, mono or stereo.