[1] Its official name is G.729-based embedded variable bit rate codec: An 8-32 kbit/s scalable wideband coder bitstream interoperable with G.729.

[2] This codec has been designed to provide better quality and more flexibility than the existing ITU-T G.729 speech coding standard.

In addition it offers various encoder and decoder modes, including the support of both 8 and 16 kHz input/output sampling frequency, compatibility with G.729B, and reduced algorithmic delay.

G.729.1 is also known as G.729 Annex J and G.729EV where EV stands for Embedded Variable (bit rate).

The G.729.1 algorithm is based on a three-stage coding structure: embedded code-excited linear prediction (CELP) coding of the lower band (50–4000 Hz), parametric coding of the higher band (4000–7000 Hz) by Time-Domain Bandwidth Extension (TDBWE), and enhancement of the full band (50–7000 Hz) by a predictive transform coding technique referred to as time-domain aliasing cancellation (TDAC) or modified discrete cosine transform (MDCT) coding.