Basic Standards for Audio Coding (3/3)

Basic Standards for Audio Coding

The need for bandwidth-saving speech transmission becomes obvious when we realize that
many branch offices, for example, are connected to their main company by a WAN conection
with a data rate of only 128 kbps. Uncompressed speech transmission would consume large
parts of the available bandwidth leaving nothing for parallel-application data-transfer or other
speech connections. A variety of codecs can be applied to ensure a good compromise
between speech quality and efficient bandwidth use.

Packet-oriented data transmission suffers from many of problems: delays, echoes, wrong
packet sequencing and finally, packet loss. State-of-the-art codecs cope with all these
problems and achieve speech quality in packet data networks which is comparable to legacy
circuit-switched networks. The best-known codecs process signal according to ITU G.711,
G.723.1, G.729 and G.729A standards.