Recommendation ITU-T G.719 describes the G.719 coding algorithm for low-complexity full-band conversational speech and audio, operating from 32 kbit/s up to 128 kbit/s.
The encoder input and decoder output are sampled at 48 kHz. The codec enables full bandwidth, from 20 Hz to 20 kHz, encoding of speech, music and general audio content. The codec operates on 20-ms frames and has an algorithmic delay of 40 ms.
The coding algorithm is based on transform coding with adaptive time-resolution, adaptive bit‑allocation and low-complexity lattice vector quantization.
This Recommendation contains an electronic attachment containing a set of test signals, which can be used together with the ANSI-C code in order to verity bit-exactness.
Amendment 1 adds new Annex A that specifies the use of the ISO base media file format as container for the G.719 bitstream addresses non-conversational use cases of the codec (e.g., call waiting music playback and recording of teleconferencing sessions, voice mail messages, online "jam"-sessions).
Amendment 1 also includes Annex B, an alternative implementation of the G.719 using floating-point arithmetic. Examples of application of the floating point implementations include DSP platforms optimized for floating point and codec implementations using desktop computers.
Amendment 2 adds new Annex C specifying the G.719 packet format, capability identifier and capability parameters and related procedures for H.245 based systems.