| Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s | |
 | |
| Status | In force |
|---|---|
| Year started | 1996 |
| Latest version | (05/06) May 2006 |
| Organization | ITU-T |
| Base standards | G.721 |
| Related standards | G.726 |
| Domain | 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 (MOS 3.9)
- 5.3 kbit/s (using 20-byte frames) using an ACELP algorithm (MOS 3.62)
- ^ "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.