1.  What is G.723.1?
   
2.  What is the difference between "G.723" and "G.723.1"?
3.  Who is the ITU?
4.  Who is the IMTC?
5.  Who developed G.723.1?
6.  How did the ITU decide upon TrueSpeech 6.3/5.3 as G.723.1?
7.  What does 6.3/5.3 refer to?
8.  How good is the speech quality of G.723.1?
9.  What is ITU H.323?
10.  What is ITU H.324?
11.  What companies support G.723.1?
12.  What is the latest version of G.723.1?
13.  Where do I get the G.723.1 Source Code for evaluation?
14.  What processing power is required to encode and decode using G.723.1 on a Pentium?
15.  What are the MIPS requirements for the Motorola 56156? for the TI C5x?
16.  How do I license G.723.1 as optimized software?
17.  Can I use the Windows Audio Compression Manager (ACM) to be able to compress and decompress audio using G.723.1?
18.  Who has licensed G.723.1 from DSP Group?

G.723.1 is the designation given to the TrueSpeech 6.3/5.3 dual rate speech codec by the International Telecommunications Union (ITU) Study Group 15. G.723.1 is intended to standardize the audio portion of videoconferencing/telephony over public telephone (POTS) networks and is part of the overall ITU H.324 standard. It is also recommended as the low bit rate speech coder for the ITU H.323 network conferencing standard which is supported by Microsoft, Intel and more than 100 other leading companies as the standard for communications on the Internet.

As of March 12, 1997, the International Multimedia Teleconferencing Consortium's (IMTC) Voice Over IP (VoIP) Forum, has recommended G.723.1 as the default low bitrate audio coder for the overall H.323 standard.

back to top

2. What is the difference between "G.723" and "G.723.1"?

At some point in the past, there existed a coder designated as G.723 which was later folded into G.726. To avoid confusion, the ITU changed the name of the currently adopted G.723 coder to G.723.1. Thus, there is no real distinction between G.723.1 and G.723 with reference to the currently adopted G.723.1 standard.

back to top

3. Who is the ITU?

The International Telecommunications Union (ITU) is an international organization chartered by the United Nations to formulate worldwide communications standards. The members represent nearly every nation in the world, with delegates typically from the largest telecommunication service providers and equipment manufacturers in the member countries. In past meetings, the "speech experts group" of the ITU (Study Group 15), with representatives from such industry leaders as AT&T, British Telecom, NTT, Siemens, and others, have evaluated technologies from the leading voice technology labs throughout the world. Based on their findings, the experts group recommended approval of DSPG's compression technology based on the advanced version of TrueSpeech. ITU-T Recommendation G.723.1 was approved on March 19, 1996.

back to top

4. Who is the IMTC?

The International Multimedia Teleconferencing Consortium (IMTC) is a non-profit industry organization with a membership of over 140 companies from various industries targeting interoperability among multiple vendor products. The IMTC approved G.723.1 as the low bitrate speech coder for Internet Telephony applications in 1997. (see also http://www.imtc.org)

back to top

5. Who developed G.723.1?

Four companies collaborated closely towards the development of the G.723.1 speech technology. These companies, led by DSP Group, include Audiocodes Ltd, France Telecom, and the University of Sherbrooke. DSP Group represents these co-developers of G.723.1 so that a potential licensee needs only to contact DSP Group and not each of these four entities separately.

back to top

6. How did the ITU decide upon TrueSpeech 6.3/5.3 as G.723.1?

TrueSpeech 6.3/5.3 was selected by the ITU as the G.723.1 standard only after extensive testing. TrueSpeech 6.3/5.3 was tested under a variety of conditions including situations with background noise, individuals speaking different languages, male and female talkers, multiple people talking simultaneously, etc. The coder was also tested to determine its robustness to handling lost packets, also called frame erasure. The ability to handle lost packets is especially important to enable high quality voice communications in the Internet environment. TrueSpeech 6.3/5.3 outperformed offerings from a number of industry leading companies under these strict testing environments to be selected by the ITU as the G.723.1 coder.

back to top

7. What does 6.3/5.3 refer to?

The G.723.1 coder has two bit rates associated with it. These are 5.3 and 6.3 kilobits per second (Kbps). The higher bit rate has better quality. The lower bit rate gives good quality and provides system designers with additional flexibility. Both rates are a mandatory part of the encoder and decoder. It is possible to switch between the two rates "on the fly." An option for variable rate operation using Voice Activity Detection (VAD), which compresses out the silent portions between words, is also possible.

back to top

8. How good is the speech quality of G.723.1?

A quality test called Mean Opinion Score (MOS) is used to rate the quality of different speech codecs. On this scale, a score of 4.0 is considered "toll" quality, the quality of speech heard through a normal telephone line. In tests performed by Dynastat, G.723.1 received a rating of 3.98 - only 2 hundredths of a point away from full toll quality! Thus, G.723.1 can enable voice communications through the Internet as well as in other applications requiring compression with voice quality equal to that experienced over a regular telephone.

Listen to TrueSpeech G.723.1 and Other Samples

back to top

9. What is H.323?

H.323 is an ITU standard for video and voice communications over packet-based networks. Therefore, it is suitable for Internet videoconferencing, telephony, on-demand audio/video, and other Internet, Intranet, and LAN communications applications. Within ITU H.323, G.723.1 is the only speech coder that will operate on a 14.4 Kbps modem. The H.323 standard also specifies multiplexing and communication control protocols as well as video compression options.

As of March 12, 1997, the International Multimedia Teleconferencing Consortium's (IMTC) Voice Over IP (VoIP) Forum, has recommended G.723.1 as the default low bitrate audio coder for the overall H.323 standard.

back to top

10. What is H.324?

H.324 is the ITU standard for videoconferencing/telephony over regular public telephone (POTS) lines. G.723.1 is currently the only very low bit rate coder within H.324 and is intended to standardize the audio portion of videoconferencing/telephony over POTS networks.

back to top

11. What companies support G.723.1?

The following are a few of the 100+ leading companies who support G.723.1:
Intel, Microsoft, IBM, Creative Labs, Dialogic, NEC, NetSpeak, Olympus Optical, Rockwell International, Siemens, Texas Instruments, US Robotics, VDOnet, VIVO Software, and more.

back to top

12. What is the latest version of G.723.1?

As of November 8, 1996, the latest version of G.723.1 is 5.1.

back to top

13. Where do I get the G.723.1 Source Code for evaluation?

Version 5.1 of the G.723.1 Source Code may be obtained from the ITU Sales Organization (www.itu.int). The ITU may be reached as follows:

ITU Sales and Marketing Service
Place des Nations
CH-1211 Geneva 20
Switzerland
http://www.itu.org/
Telephone: + 41-22-730-6141 English
Telephone: + 41-22-730-6142 French
Telephone: + 41-22-730-6143 Spanish
Fax: + 41-22-730-5194
Internet: sales@itu.int
Contact page

back to top

14. What processing power is required to encode and decode using G.723.1 on a Pentium?

Using a Pentium 100MHz, the G.723.1 32 bit DLL will encode and decode at less than 45% of real time. (The 16 bit DLL will encode/decode at approximately 85% of real time.)

back to top

15. What are the MIPS requirements for the Motorola 56156? for the TI C5x?

Motorola 56156 Estimates:
Encode (6.3) = 19.4 Decode (6.3) = 1.7

TI TMS320C52 Estimates:
Encode (6.3) = 21.1 Decode (6.3) = 2.6
Encode (5.3) = 22 Decode (5.3) = 2.6

TI TMS320C50, C51, C53 Estimates:
Encode (6.3) = 19.7 Decode (6.3) = 2.2
Encode (5.3) = 21.3 Decode (5.3) = 2.2

back to top

16. How do I license G.723.1 as optimized software?

Using G.723.1 software first involves obtaining the patent rights. The G.723.1 patent licensing fee structure varies depending on your particular application (i.e. server-based gateway, Client S.W/H.W application, etc.) For licensing information please contact our TrueSpeech licensing manager at TrueSpeech@dsp.co.il, or browse to the Licensing model page. DSP Group represents 5 of the 7 patent holders for G.723.1, including DSPG, Audiocodes Ltd, France Telecom, the University of Sherbrooke, and NTT. DSPG is continuing to spearhead the effort to include all patent holders under one roof for one-stop G.723.1 patent licensing. In addition to G.723.1 patent licensing, DSP Group has developed optimized "ready-to-go" software versions of G.723.1 for the Pentium and various DSPs to facilitate faster time to market. Optimized versions are currently available for the Motorola 56k family, the TI C5x, the Analog Devices 21xx, the OakDSPCore, PalmDSPCore and the Pentium platforms.

back to top

17. Can I use the Windows Audio Compression Manager (ACM) to be able to compress and decompress audio using G.723.1?

Licensees can use G.723.1 for their own applications and for creating applications which are interoperable with products of other G.723.1 Licensees, but are restricted from permitting access to the coder for third party applications through the ACM.

back to top

18. Who has licensed G.723.1 from DSP Group?

There are currently over 30 companies who have licensed G.723.1 from DSP Group. The list includes such names as Microsoft, Intel, U.S. Robotics, Siemens, ACER, NEC, Dialogic, Smith Micro, 8x8, Rockwell, PictureTel, Fujitsu, White Pine, Netspeak, VDOnet, Vocaltec, Voxware, RealNetworks, and others.

back to top