Editing G.723.1 (section)

{{short description|ITU-T Recommendation}}
{{Infobox technology standard
| title             = G.723.1
| long_name         = Dual rate speech coder for multimedia communications transmitting at 5.3 and {{val|6.3|u=kbit/s}}
| image             = Pcm.svg 
| caption           = 
| status            = In force
| year_started      = 1996
| version           = (05/06)
| version_date      = May 2006
| preview           = 
| preview_date      = 
| organization      = [[ITU-T]]
| committee         = 
| base_standards    = [[G.721]]
| related_standards = [[G.726]]
| abbreviation      = 
| domain            = [[audio compression (data)|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 {{val|30|u=ms}} frames. An algorithmic look-ahead of {{val|7.5|u=ms}} duration means that total algorithmic delay is {{val|37.5|u=ms}}.<ref>{{Cite web|title=G.723.1: Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s|url=https://www.itu.int/rec/T-REC-G.723.1|url-status=live|archive-url=https://web.archive.org/web/20210613184127/https://www.itu.int/rec/T-REC-G.723.1|archive-date=2021-06-13|access-date=2021-06-13|website=www.itu.int}}</ref> Its official name is ''Dual rate speech coder for multimedia communications transmitting at 5.3 and {{val|6.3|u=kbit/s}}''. It is sometimes associated with a [[Truespeech]] trademark in coprocessors produced by [[DSP Group]].<ref name="dsp-ct8022">{{cite web|title=CT8022 VOIP/VON G.723.1, G729AB TRUESPEECH® CO-PROCESSOR|url=http://nic.ath.cx/PDF/computer/LinuxJack/CT8022.pdf|archive-url=https://web.archive.org/web/20180404222124/http://nic.ath.cx/PDF/computer/LinuxJack/CT8022.pdf|access-date=4 April 2018|archive-date=4 April 2018|quote=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.}}</ref>

This is a completely different codec from [[G.723]].

There are two [[bit rate]]s at which G.723.1 can operate:
* {{val|6.3|u=kbit/s}} (using 24-byte frames) using a [[MPC-MLQ]] algorithm ([[Mean opinion score|MOS]] 3.9)
* {{val|5.3|u=kbit/s}} (using 20-byte frames) using an [[ACELP]] algorithm ([[Mean opinion score|MOS]] 3.62)