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ITU-T G.711.1 (03/2008)
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ITU-T G.711.1 (03/2008)
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Wideband embedded extension for G.711 pulse code modulation
Recommendation ITU-T G.711.1 describes a G.711 embedded wideband speech and audio coding algorithm operating at 64, 80 and 96 kbit/s.
The encoder input and decoder outputs are sampled at 16 kHz by default, but 8‑kHz sampling is also supported. When sampled at 16 kHz, the output of the G.711.1 coder can encode signals with a bandwidth of 50‑7000 Hz at 80 and 96 kbit/s, and for 8‑kHz sampling the output may produce signals with a bandwidth ranging from 50 up to 4000 Hz, operating at 64 and 80 kbit/s (the bandwidth of the narrow-band signal output from the decoder is characterized by the built‑in split‑band filterbank which has a frequency cut‑offs at 4000 Hz). At 64 kbit/s, G.711.1 is compatible with G.711, hence an efficient deployment in existing G.711-based voice over IP (VoIP) infrastructures is foreseen. The coder operates on 5 ms frames, has a maximum algorithmic delay of 11.875 ms, and has a worst‑case computational complexity of 8.70 weighted million operations per second (WMOPS).
The encoder produces an embedded bitstream structured in three layers corresponding to three available bit rates: 64, 80 and 96 kbit/s. The bitstream can be truncated at the decoder side or by any component of the communication system to adjust the bit rate to the desired value, but since it does not contain any information on which layers are contained, an implementation would require outband signalling on which layers are available.
The underlying algorithm has a three‑layer coding structure: log companded pulse code modulation (PCM) of the lower band including noise feedback, embedded PCM extension with adaptive bit allocation for enhancing the quality of the base layer in the lower band, and weighted vector quantization coding of the higher band based on modified discrete cosine transformation (MDCT).
Annex A defines an alternative implementation of the G.711.1 algorithm using floating-point arithmetic to facilitate its use on hardware optimized for floating-point operations. The accompanying floating-point C-code is fully interoperable with the fixed-point C-code and provides equivalent quality.
Annex B contains the RTP payload format, capability identifiers and parameters for signalling of G.711.1 capabilities using H.245. The packet format is fully compatible with the corresponding G.711.1 RTP definitions to allow seamless interoperability.
Appendix I describes a supplementary postfilter for use in the decoder. This postfilter enhances the quality of the decoded signal when a legacy G.711 or only the basic log companded PCM part of the G.711.1 bitstream are available. It is intended for end‑user terminals and usage in tandem scenarios should be avoided (such as in a signal mixer or bitstream translators).
This Recommendation includes an electronic attachment containing a non-exhaustive set of test signals for use with the ANSI C code.
ANSI C source code is provided for both the main body's fixed-point arithmetic implementation as well as for Annex A's floating-point alternative specification.
This edition incorporates changes needed to correct defects in the pre-published text of this Recommendation. All updates are related to typos and editorial corrections of the text, i.e., the algorithm description, and do not modify the other parts of the Recommendation including Annex A, such as bit-exactness of the supplied C‑source code.
Citation:
https://handle.itu.int/11.1002/1000/9365
Series title:
G series: Transmission systems and media, digital systems and networks
G.700-G.799: Digital terminal equipments
G.710-G.729: Coding of voice and audio signals
Approval date:
2008-03-15
Provisional name:
G.711-WB
Approval process:
AAP
Status:
Superseded
Observation:
Due to the data volume, only text and the source codes are available here. Test vectors are downloadable free of charge from ITU-T test signals database at: http://handle.itu.int/11.1002/2000/9365. The CD containing all the text, the Floating-point reference implementation and the Associated test vectors can be provided from Sales department (Email: sales@itu.int). The published text of this Recommendation includes the modifications introduced by G.711.1 (2008) Amend.1 and G.711.1 (2008) Amend.2.
Maintenance responsibility:
ITU-T Study Group 16
Further details:
Patent statement(s)
Development history
Associated test signals
Editions
Related Supplement(s)
Related technical papers and reports
Ed.
ITU-T Recommendation
Status
Summary
Table of Contents
Download
2.1
G.711.1 (2012) Amd. 1 (10/2014)
In force
here
-
here
2
G.711.1 (09/2012)
In force
here
here
here
1.5
G.711.1 (2008) Amd. 5 (03/2011)
Superseded
here
here
here
1.4
G.711.1 (2008) Amd. 4 (11/2010)
Superseded
here
here
here
1.3
G.711.1 (2008) Amd. 3 (10/2010)
Superseded
here
here
here
1.2
G.711.1 (2008) Amd. 2 (03/2009)
Superseded
here
-
here
1.1
G.711.1 (2008) Amd. 1 (11/2008)
Superseded
-
-
here
1
G.711.1 (03/2008)
Superseded
here
here
here
ITU-T Supplement
Title
Status
Summary
Table of contents
Download
G Suppl. 4 (12/1972)
Certain methods of avoiding the transmission of excessive noise between interconnected systems
In force
-
-
here
G Suppl. 5 (10/1984)
Measurement of the load of telephone circuits under field conditions
In force
-
-
here
G Suppl. 7 (12/1972)
Loss-frequency response of channel-translating equipment used in some countries for international circuits
In force
here
here
here
G Suppl. 8 (12/1972)
Method proposed by the Belgian telephone administration for interconnection between coaxial and symmetric pair systems
In force
-
-
here
G Suppl. 17 (10/1984)
Group-delay distortion performance of terminal equipment
In force
-
-
here
G Suppl. 19 (10/1984)
Digital crosstalk measurement (method used by the Administrations of France, the Netherlands and Spain)
In force
-
-
here
G Suppl. 22 (10/1984)
Mathematical models of multiplex signals
In force
-
-
here
G Suppl. 26 (10/1984)
Estimating the signal load margin of FDM wideband amplifier equipment and transmission systems
In force
-
-
here
G Suppl. 27 (10/1984)
Interference from external sources
In force
-
-
here
G Suppl. 28 (10/1984)
Application of transmultiplexers, FDM codecs, data-in-voice (DIV) systems and data-over-voice (DOV) systems during the transition from an analogue to a digital network
In force
-
-
here
G Suppl. 32 (11/1988)
Transfer of alarm information on 60-channel transmultiplexing equipment
In force
-
-
here
G Suppl. 34 (11/1988)
Temperature in underground containers for the installation of repeaters
In force
-
-
here
G Suppl. 35 (11/1988)
Guidelines concerning the measurement of wander
In force
-
-
here
G Suppl. 36 (11/1988)
Jitter and wander accumulation in digital networks
In force
-
-
here
G Suppl. 39 (02/2016)
Optical system design and engineering considerations
In force
here
here
here
G Suppl. 40 (10/2018)
Optical fibre and cable Recommendations and standards guideline
In force
here
here
here
G Suppl. 41 (02/2018)
Design guidelines for optical fibre submarine cable systems
In force
here
here
here
G Suppl. 42 (10/2018)
Guide on the use of the ITU-T Recommendations related to optical fibres and systems technology
In force
here
here
here
G Suppl. 43 (02/2011)
Transport of IEEE 10GBASE-R in optical transport networks (OTN)
In force
here
here
here
G Suppl. 44 (06/2007)
Test plan to verify B-PON interoperability
In force
here
here
here
G Suppl. 45 (09/2022)
Power conservation in optical access systems
In force
here
here
here
G Suppl. 46 (05/2009)
G-PON interoperability test plan between optical line terminations and optical network units
In force
here
here
here
G Suppl. 47 (09/2012)
General aspects of optical fibres and cables
In force
here
here
here
G Suppl. 48 (06/2010)
10-Gigabit-capable passive optical networks: Interface between media access control with serializer/deserializer and physical medium dependent sublayers
In force
here
here
here
G Suppl. 49 (09/2020)
Rogue optical network unit (ONU) considerations
In force
here
here
here
G Suppl. 50 (09/2011)
Overview of digital subscriber line Recommendations
In force
here
here
here
G Suppl. 51 (06/2017)
Passive optical network protection considerations
In force
here
here
here
G Suppl. 52 (09/2012)
Ethernet ring protection switching
In force
here
here
here
G Suppl. 53 (12/2014)
Guidance for Ethernet OAM performance monitoring
In force
here
here
here
G Suppl. 54 (07/2015)
Ethernet linear protection switching
In force
here
here
here
G Suppl. 55 (12/2023)
Radio-over-fibre (RoF) technologies and their applications
In force
here
here
here
G Suppl. 56 (02/2016)
OTN transport of CPRI signals
In force
here
here
here
G Suppl. 57 (07/2015)
Smart home profiles for 6LoWPAN devices
In force
here
here
here
G Suppl. 58 (12/2023)
Optical transport network module framer interfaces
In force
here
here
here
G Suppl. 59 (02/2018)
Guidance on optical fibre and cable reliability
In force
here
here
here
G Suppl. 60 (09/2016)
Ethernet linear protection switching with dual node interconnection
In force
here
here
here
G Suppl. 62 (02/2018)
Gfast certification
In force
here
here
here
G Suppl. 64 (02/2018)
PON transmission technologies above 10 Gb/s per wavelength
In force
here
here
here
G Suppl. 65 (10/2018)
Simulations of transport of time over packet networks
In force
here
here
here
G Suppl. 66 (09/2020)
5G wireless fronthaul requirements in a passive optical network context
In force
here
here
here
G Suppl. 67 (07/2019)
Application of optical transport network Recommendations to 5G transport
In force
here
here
here
G Suppl. 68 (12/2023)
Synchronization operations, administration and maintenance requirements
In force
here
here
here
G Suppl. 69 (09/2020)
Migration of a pre-standard network to a metro transport network
In force
here
here
here
G Suppl. 70 (09/2020)
Supplement on sub 1 Gbit/s services transport over optical transport network
In force
here
here
here
G Suppl. 71 (12/2023)
Optical line termination capabilities for supporting cooperative dynamic bandwidth assignment
In force
here
here
here
G Suppl. 72 (04/2021)
Modelling consideration for optical media networks
In force
here
here
here
G Suppl. 73 (10/2021)
Influencing factors on quality of experience for multiview video (MVV) services
In force
here
here
here
G Suppl. 74 (12/2021)
Network slicing in a passive optical network context
In force
here
here
here
G Suppl. 75 (12/2021)
5G small cell backhaul/midhaul over TDM-PON
In force
here
here
here
G Suppl. 76 (12/2021)
Optical transport network security
In force
here
here
here
G Suppl. 77 (06/2022)
Supplement 77 to ITU-T G-series of Recommendations - Influencing factors on quality of experience (QoE) for video customized alerting tone (CAT) and video customized ringing signal (CRS) services
In force
here
here
here
G Suppl. 78 (09/2022)
Use case and requirements of fibre-to-the-room for small business applications
In force
here
here
here
G Suppl. 79 (12/2023)
Latency control and deterministic capability over a PON system
In force
here
here
here
Title
Approved on
Download
Roadmap for QoS and QoE in the ITU-T Study Group 12 context (TR-RQ)
2023
here
Considerations on the use of GNSS as a primary time reference in telecommunications
2020
here
Use of G.hn in industrial applications
2020
here
Practical procedures for subjective testing
2011
here
ISDN field trial guidelines
1991
here
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