Abstract
A real-time implementation of an ITU-T C.726 adaptive differential pulse code modulation (ADPCM) codec is developed for desktop, packet switched audio-conferencing over the Internet. The real-time codec is implemented in C on a UNIX (Solaris) platform. A non-real-time version also exists for the Windows 95 operating system. The real-time G.726 implementation is compared to existing speech coders on the basis of output speech quality. These comparisons are made with the notion that all competing coders operate at the same output bit rate (16 Kbps). The developed C.726 codec is compared to an existing implementation of G.723, its equivalent, as well as multiple configurations of a low delay tree codec, also developed during the course of this research. The tree codec consists of a non-real-time, Windows 95 based, low delay, low complexity, 16 Kbps algorithm. The developed tree coding algorithm incorporates a G.726 code generator, a (M,L) tree search mechanism, a single symbol release rule, and a mean squared error (MSE) distortion measure.
Kokes, Mark Gavin (1997). A real-time implementation of G.726 with tree coding. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1997 -THESIS -K65.