ACELP®.net � Beyond the Standards

"ACELP.net would here be my recommended codec of choice for 5-15 kbps speech coding." � Audio Codec Comparisons, David Weekly, June 27, 1999, http://david.weekly.org/audio/

"Microsoft clearly recommends using the ACELP® codec by VoiceAge. This is the same codec RealNetworks uses to encode speech. . . . Indeed, when encoded at just 16 kbps (one-fourth the size), the ACELP voice codec nearly matches MP3 quality at 64 kbps!”
� "Microsoft Clarifies Audio Testing Results for Windows Media Technologies 4.0," Microsoft Press Release, April 13, 1999

ACELP®.net, like prestigious standards such as EFR GSM, IS-136, TETRA, G.723.1, G.729 and G.729 Annex A, is based on ACELP® technology. This state-of-the-art technology has now been adapted to meet the needs of IP networks and the PC platform by using an improved, net-adapted packetization method that outperforms conventional approaches. In particular, it minimizes the impact of errors while significantly improving error correction possibilities in case of data-packet losses. Through frame concatenation and interlacing, the communication channel is made more robust.

The ACELP®.net family includes a dual-rate codec (8.5/6.5 kbps), a fixed rate codec (5.0 kbps) and a wideband codec (16 kbps). The dual-rate version of ACELP®.net has the ability to switch bit rates on the fly to effectively handle network inconsistencies. ACELP®.net provides toll-quality compression at 8.5 kbps and near-toll quality at lower rates.

The ACELP®.net family has already gained recognition, with ACELP®.net being the preferred low bit rate speech codec in RealAudio® and being included in both Microsoft MediaPlayer® and Audible® ready equipment. This new technology can be rapidly harnessed for applications such as broadcast over Internet (multicasting), multimedia email and multimedia conferencing.