Annex J/G.729 describes an extension of ITU-T Rec. G.729 for 8-32 kbit/s scalable wideband speech and audio coding algorithm interoperable with ITU-T Rec. G.729 and its Annexes A and B.

The details of Annex J are specified and published in ITU-T Rec. G.729.1 in order to provide for easier maintenance and to give it better visibility.