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ITU-T G.711.1 (09/2012)
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ITU-T G.711.1 (09/2012)
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ITU-T G.711脉冲编码调制的宽带嵌入式扩展
ITU-T G.711.1建议书描述了运行在64、80和96 kbit/s的ITU-T G.711嵌入式宽带语音和音频编码算法。
编码器的输入端和解码器的输出端的采样缺省值为16 kHz,但也支持8 kHz的采样。当以16 kHz 进行采样时,ITU-T G.711.1编码器的输出能够以80和96 kbit/s的比特率、50 7000 Hz的带宽对信号进行编码,当以8 kHz进行采样时,编码器的输出端可以产生带宽范围为50到4000 Hz、以64和80 kbit/s的比特率工作的信号(解码器输出的窄带信号的带宽,解码器的特征是内嵌的频带分割的、截止频率为4000 Hz的滤波器组),当比特率为64 kbit/s时,ITU-T G.711.1建议书与ITU-T G.711建议书一致;因此,在现有的基于ITU-T G.711的网络电话(VoIP)基础设施中有效部署是可以预见的。工作帧长为5 ms的编码器具有11.875 ms的最长算法时延,最坏情况计算复杂度为8.70个加权百万操作每秒(WMOPS)。
编码器产生一个三层的嵌入式比特流结构,与三种可用的比特率相对应:64、80和96 kbit/s,该比特流能够在解码器端或被通信系统的任何部件截短,以便将比特率调整到期望的数值,但是由于它不含有关于包含了哪一层的任何信息,实现将需要关于哪一层是有效的带外信令。
基本的算法具有一个三层的编码结构:低频带的对数压扩脉冲编码调制(PCM)包括噪声反馈,为了提高低频带基层的质量、具有自适应比特分配的嵌入式PCM扩展,基于改进的离散余弦变换(MDCT)的高频带加权矢量量化编码。
附件A定义了ITU-T G.711.1算法的一种采用浮点运算的可选实现,以便于在针对浮点运算进行过优化的硬件上使用,附带的浮点C代码与定点C代码能够完全互操作,提供同等的品质。
附件B包含了适用于采用ITU-T H.245建议书的ITU-T G.711.1信令性能的RTP负载格式、性能标识符和参数,数据包格式与相应的ITU-T G.711 RTP定义完全 一致以便实现无缝式互操作。
附件C描述了将ITU-T G.711.0无损压缩算法应用于ITU-T G.711.1的一种算法,由于ITU-T G.711.0建议书的算法更为高效,当应用于较长的帧时,为了获得高效的压缩率,应尽可能将 ITU-T G.711.0能够支持的多个ITU-T G.711.1帧一起编码,这种扩展的使用与ITU- T G.711.1建议书相比,不会引起质量下降,因为它是ITU-T G.711.1比特流的ITU-T G.711部分的无损编码,此外,没有附加的算法时延;其时延等于ITU-T G.711.1的时延加上所选择大小的数据包减去5毫秒,它保持了和ITU-T G.711.1建议书相同的对于数据包丢失的鲁棒性,并且在帧错误的情况下不会产生误差传播,所提议的方案能够以最小的复杂度、很容易地转换为ITU-T G.711.1或者ITU-T G.711.0的代码。
附件D描述了一种可伸缩的超宽带(SWB,50 14000 Hz)语音和音频编码算法,对于ITU-T G.711.1 80 kbit/s核心,工作在96 到112 kbit/s,对于ITU-T G.711.1 96 kbit/s 核心,工作在112 到 128 kbit/s。ITU-T G.711.1超宽带扩展编解码器与ITU-T G.711和ITU-T G.711.1均能互操作,ITU-T G.711.1 SWB编码器输出的带宽为50-14000 Hz,编码器工作帧长为5ms,算法时延为12.8125 ms,最坏情况复杂度为21.498 个MOPS。缺省地,编码器的输入和解码器的输出均以32 kHz进行采样,超宽带编码器产生一个两层的嵌入式比特流结构,与两个可用的比特率相对应:96 到112 kbit/s 或者 112 到128 kbit/s,步长为16 kbit/s,取决于所选择的ITU-T G.711.1核心。该比特流能够在解码器端或者被通信系统的任何部件截短,以便立即将比特率调整到期望的数值,而不需要带外信令。在ITU-T G.711.1 80 kbit/s 模式或者 96 kbit/s模式下,ITU-T G.711.1 SWB能够与ITU-T G.711.1完全互操作,基本的算法包括三个主要部分:高频带增强,带宽扩展(BWE)和基于代数矢量量化(AVQ)的改进的离散余弦变换(MDCT)中的变换编码。
附件E描述了ITU-T G.711.1建议书附件D的一个提议的基于浮点运算的备选实现草案,当附件D提供了位精确、定点的技术要求,以及从ITU-T获得的定点C源代码时,可供选择的浮点实现对于配备了浮点处理器的平台是有用的,已发现这个可选的浮点运算与附件D在所有配置下均能完全互操作,包括交叉配置。
附件F描述了宽带编解码器ITU-T G.711.1的立体声扩展,以及它的超宽带扩展ITU-T G.711.1附件D,它最适合于以有限的附加比特率传输立体声信号,同时保持与编解码器的完全兼容,附件F工作在96 到 160 kbit/s:5个比特率从112 到 160 kbit/s的超宽带立体声,比特率为96和128 kbit/s的2个宽带立体声。宽带立体声模式向下兼容传统的ITU-T G.711和 ITU-T G.711.1,同时超宽带模式提供了与单声道窄带ITU-T G.711、单声道宽带 ITU-T G.711.1 和超宽带 ITU-T G.711.1附件D的向下兼容,立体声编解码器工作帧长为5 ms,对于宽带立体声,算法时延为18.125 ms,对于超宽带立体声,算法时延为19.0625 ms。对于宽带和超宽带工作模式,编码器的输入和解码器的输出分别以16 kHz 和 32 kHz进行采样,基本的算法包括三个主要部分:编码器端的立体声参数分析和混音,解码器端的立体声合成。第一个立体声扩展层是一个16 kbit/s层,包含了基本的立体声参数,整个宽带声道间时间差/声道间相位差/声道间相干性,分波段声道间电平差和低频分波段声道间相位差。第二个立体声层是一个16 kbit/s层,在这最后一层中,会发送更大带宽的声道间相位差,从而进一步提高立体形象,比特流能够被解码器或者通信系统的任何部件截短,以便立即将比特率调整到期望的数值,包括窄带ITU-T G.711、宽带ITU-T G.711.1和超宽带ITU-T G.711.1附件D比特率,而不需要带外信令。
附录I描述了一个用于解码器的辅助的后置滤波器,当可以获得传统的ITU-T G.711或者只能获得ITU-T G.711.1比特流的基本对数压扩PCM部分时,这个后置滤波器能够提高解码信号的质量,它计划用于最终的用户终端,应避免在串联情况下使用它(例如,在一个信号混合器或者比特流译码器中),附录II和III分别提供了关于帧长选择和ITU-T G.711.1 LLC 比特流的ITU-T G.711.0比特流部分解码的信息。
ITU-T G.711.1建议书的附录IV为采用ITU-T G.711.1附件D(ITU-T G.711.1-SWB)的中端(MS)立体声规定了一套编码方案,通过将中端立体声编码引入到立体声终端,能够以非常低的复杂度实现与单声道设备的互操作,基本的编码方案如下:将左-右(LR)立体声的两个声道转换为MS立体声的两个声道,然后采用ITU-T G.711.1-SWB对各个声道的信号独立进行编码;在解码器端,对来自编码器的比特流的MS声道分别进行解码,然后将MS声道的解码信号反向变换为LR声道的信号,LR-MS变换及其逆变换采用常规方式进行。在编码器端,LR-MS变换需要每个样本增加两次算术运算,在解码器中,MS-LR变换需要一个运算子。在STL2009中,参见ITU-T G.191建议书(2010)基本运算子实现,总的变换复杂度约等于0.2个WMOPS,各个声道的编码算法与ITU-T G.711.1建议书附件D中的算法相同。
为该建议书正文以及附件A、C、D、E和F中指定的算法提供了ANSI C源代码,这些ANSI C源代码是该建议书的组成部分。
还为使用这些ANSI C源代码提供了详尽的测试信号组,作为该建议书的电子附件。应注意到某些文本向量太长,不便于与源代码一起发行,尤其是对于附件F。测试向量能够从国际电联网站免费下载:http://itu.int/net/itu-t/sigdb/speaudio/Gseries.htm#G.711.1。
Citation:
https://handle.itu.int/11.1002/1000/11672
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:
2012-09-13
Provisional name:
G.711-WB
Approval process:
AAP
Status:
In force
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.
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
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Summary
Table of contents
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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 (07/2024)
Optical fibre and cable Recommendations and standards guideline
In force
-
-
here
G Suppl. 41 (07/2024)
Design guidelines for optical fibre submarine cable systems
In force
-
-
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. 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
G Suppl. 80 (07/2024)
Use case and requirements of fibre-based in-premises networking for home application (FIP4H)
In force
-
-
here
G Suppl. 81 (07/2024)
Practical aspects of PON security
In force
-
-
here
G Suppl. 82 (07/2024)
Enhanced optical line termination with information technology functions
In force
-
-
here
G Suppl. 83 (07/2024)
Supplement on the use of options in PTP profile with full timing support from the network
In force
-
-
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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