G.723.1
Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s | |
audio compression | |
License | Freely available |
---|---|
Website | https://www.itu.int/rec/T-REC-G.723.1 |
G.723.1 is an audio codec for voice that compresses voice audio in 30 ms frames. An algorithmic look-ahead of 7.5 ms duration means that total algorithmic delay is 37.5 ms.[1] Its official name is Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s. It is sometimes associated with a Truespeech trademark in coprocessors produced by DSP Group.[2]
This is a completely different codec from G.723.
There are two bit rates at which G.723.1 can operate:
- 6.3 kbit/s (using 24-byte frames) using a MPC-MLQ algorithm (MOS3.9)
- 5.3 kbit/s (using 20-byte frames) using an ACELP algorithm (MOS3.62)
Use
G.723.1 is mostly used in Voice over IP (
G.723.1 is a required audio codec in the H.324 ITU-T recommendation for H.324 terminals offering audio communication. In 3GPP 3G-324M specification support for G.723.1 is not mandatory, but recommended.
Features
- Sampling frequency 8 kHz/16-bit (240 samples for 30 ms frames)
- Fixed bit rate (5.3 kbit/s with 20 byte 30 ms frames, 6.3 kbit/s with 24 byte 30 ms frames)
- Fixed frame size for each rate (5.3 kbit/s with 20 byte 30 ms frames, 6.3 kbit/s with 24 byte 30 ms frames)
- Algorithmic delay is 37.5 ms per frame, with 7.5 ms look-ahead delay
- G.723.1 is a hybrid speech coder, with high bit rate using multi-pulse maximum likelihood quantization (MP-MLQ) and low bit rate using algebraic code-excited linear prediction (ACELP)
- The complexity of the algorithm is rated at 25, using a relative scale where G.729ais 15.
- G.723.1 Annex A defines 4 byte silence insertion descriptor (SID) frame for Comfort Noise Generation
- μ-law)
- PSQM testing under network stress yields μ-law)
Licensing
As of January 1, 2017, the
The authorized
Members of the G.723.1
See also
- List of codecs
- Comparison of audio coding formats
- RTP audio video profile
References
- ^ "G.723.1: Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s". www.itu.int. Archived from the original on 2021-06-13. Retrieved 2021-06-13.
- ^ "CT8022 VOIP/VON G.723.1, G729AB TRUESPEECH® CO-PROCESSOR" (PDF). Archived from the original (PDF) on 4 April 2018. Retrieved 4 April 2018.
The CT8022 has built-in TrueSpeech 8.5 (compatible with Microsoft Sound System 2.0, and a standard part of Microsoft Windows 95), and TrueSpeech G.723.1 (for H.323 and H.324). [...] The CT8022 provides two additional non-ITU TrueSpeech data rates at 4.8 and 4.1 KBPS.
- ^ "SiproLAB Telecom - patent pool creation and management for standardized telecommunication technologies". 2017-12-22. Archived from the original on 2017-12-22. Retrieved 2018-01-10.
- ^ VoiceAge Corporation (2007-10-14). "G.723.1 Licensing". Archived from the original on 2007-10-14. Retrieved 2009-09-17.
- ^ Sipro Lab Telecom (2007-10-25). "FAQ G.729 and G.723.1". Archived from the original on 2007-10-25. Retrieved 2009-09-17.
- ^ Sipro Lab Telecom (2006-10-29). "G.723.1, the highest ITU-T compression ratio". Archived from the original on 2006-10-29. Retrieved 2009-09-17.
- ^ Sipro Lab Telecom (2006-10-29). "G.723.1 - Members". Archived from the original on 2006-10-29. Retrieved 2009-09-17.
External links
- ITU-T Recommendation G.723.1 - technical specification
- Intellectual Property Rights page on ITU website (with link to patent declaration database)