Institute for Telecommunication Sciences
the research laboratory of the National Telecommunications and Information Administration

Stephen D. Voran

Abstract: The lossless compression algorithm specified in ITU-T Recommendation G.711.0 provides bit-exact G.711 speech coding at reduced bit-rates. We introduce two Look-Up Coders (LUCs) that also offer bit-exact G.711 speech coding at reduced rates but the LUCs do not use arithmetic operations and hence eliminate the need for a processor. Instead they read in eight G.711 symbols, reinterpret those 64 bits to form eight new symbols that carry temporal information, then look up Huffman codes for those new symbols. When compared to G.711.0, LUC rates are 9% to 40% higher and they require 2 to 8 kB additional ROM, but LUCs eliminate about one million weighted arithmetic operations per second. LUCs reduce the 8 b/smpl G.711 rate to 3.8 to 6.7 b/smpl, depending on speech and noise levels.

Keywords: speech coding; G.711; G.711.0; lossless compression; PCM


To request a reprint of this report, contact:

Lilli Segre, Publications Officer
Institute for Telecommunication Sciences
(303) 497-3572
LSegre@ntia.gov

For technical information concerning this report, contact:

Stephen D. Voran
Institute for Telecommunication Sciences
(303) 497-3839
svoran@ntia.doc.gov


Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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