An audio codec (COder/DECoder) converts analog audio signals into digital signals for transmission or encodes them for storage. A receiving device converts the digital signals back to analog form using an audio decoder for playback. A video codec accomplishes the same task for video signals.

In any communication transceiver (transmit/receiver), a codec is one of the basic building blocks for efficient transmission of data.

The Specification of speech and audio codecs has been one of ETSI's (and 3GPP’s) many success stories.

Our Role & Activities

Within the 3GPP Technical Specification Group Service and System Aspects (SA), the main objectives of the 3GPP TSG SA WG4 (SA4) are the specifications of codecs for speech, audio, video, graphics and other media types related to emerging services such as extended realities (XR) and gaming, as well as the system and delivery aspects of such contents.

See the 3GPP Codec Working Group SA4 Terms of Reference here: 3GPP TSG SA WG4.


Subject of specification series 3G and beyond/GSM
(R99 and later)
GSM only
(Rel-4 and later)
GSM only
(before Rel-4)
CODECs 26 series 46 series 06 series


Related Committees