G.723.1 Speech Coder and Decoder

Matlab implementation of ITU-T G.723.1 speech coder and decoder

This package implements the ITU-T G.723.1 speech coder and decoder in Matlab. The goal of the package is to provide a well-documented and modular program that was designed to facilitate experimentation and research using a practical coder as a base.

The coder implements the multipulse mode of G.723.1 (running at 6.3 kb/s). The decoder can decode all modes of the coder (ACELP at 5.3 kb/s, multipulse at 6.3 kb/s, discontinuous-transmission, packet loss concealment).

The standard interface between the coder and decoder is a bit file (compatible with the bit files generated by the ITU-T reference code). A second option passes information between the coder and decoder using a Matlab data file. This option allows for testing by passing quantized or unquantized information between the coder and the decoder.

A report [1] describing the G.723.1 and the Matlab implementation is included with the distribution. ITU-T Recommendation G.723.1 [2] is available on-line. The recommendation includes reference code (in C) and test files.

Version 3 of the package (Dec. 2020) updates the audio file reading routines to use newer Matlab functions. This package has been tested on Matlab 2015b and later versions.

1. P. Kabal, ITU-T G.723.1 Speech Coder: A Matlab Implementation, MMSP Lab Technical Report, Dept. Electrical & Computer Engineering, McGill University, updated December 2017 (available on-line at http://www-mmsp.ece.mcgill.ca/Documents)

2. ITU-T Recommendation G.723.1, Dual Rate Speech Coder for Multimedia Communications Transmitting at 5.3 and 6.3 kbit/s, March 1996.