1、 Recommendation ITU-R BS.2051-1 (06/2017) Advanced sound system for programme production BS Series Broadcasting service (sound) ii Rec. ITU-R BS.2051-1 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectru
2、m by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Co
3、nferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statement
4、s and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Recommendations (Also avail
5、able online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite
6、services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals an
7、d frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2017 ITU 2017 All rights reserved. No part of this publication may be reproduced, by any means
8、whatsoever, without written permission of ITU. Rec. ITU-R BS.2051-1 1 RECOMMENDATION ITU-R BS.2051-1 Advanced sound system for programme production (Question ITU-R 135/6) (2014-2017) Scope This Recommendation specifies an advanced sound system with and without accompanying picture, beyond systems sp
9、ecified in Recommendation ITU-R BS.775. An advanced sound system uses audio data in combination with an appropriate set of metadata to specify a sound scene to be delivered/broadcasted. The specifications include requirements for signalling the properties of advanced sound content and loudspeaker la
10、yout to be used in content production for advanced sound systems. The advanced sound system can apply to the sound component of television and expanded large screen digital imagery (LSDI) programmes, as well as for sound only programmes. Keywords Advanced sound system, channel-based sound system, ob
11、ject-based sound system, scene-based sound system, multichannel audio, loudspeaker layouts, immersive audio The ITU Radiocommunication Assembly, considering a) that Recommendation ITU-R BS.775 Multichannel stereophonic sound system with and without accompanying picture, specifies a multichannel ster
12、eophonic sound system with three front channels and two rear/side channels together with an optional low frequency effect (LFE) channel, as the highest level in a hierarchy of multichannel sound systems that range from 1/0 (monophonic) up to 3/2; b) that Recommendation ITU-R BT.1769 Parameter values
13、 for an expanded hierarchy of LSDI image formats for production and international programme exchange, specifies an expanded hierarchy of LSDI image formats for production and international programme exchange; c) that Recommendation ITU-R BT.709 Parameter values for the HDTV standards for production
14、and international programme exchange, specifies HDTV system image parameters; d) that Recommendation ITU-R BT.2020 Parameter values for ultra-high definition television systems for production and international programme exchange, specifies UHDTV image system parameters; e) that the wide field of vie
15、w image presentation of expanded-LSDI, HDTV, and ultra-high definition television (UHDTV) programmes benefit from spatially enhanced sound beyond the 5.1 channel sound; f) that Recommendation ITU-R BS.1909 Performance requirements for an advanced multichannel stereophonic sound system for use with o
16、r without accompanying picture, specifies the requirements for an advanced sound system with or without accompanying picture; g) that Report ITU-R BS.2159 Multichannel sound technology in home and broadcasting applications, includes the results of subjective evaluation experiments on loudspeaker lay
17、out to meet the requirements described in Recommendation ITU-R BS.1909, 2 Rec. ITU-R BS.2051-1 recommends 1 that static or dynamic metadata/descriptors meeting the requirements described in Annex 1 should be used to signal the properties of all audio signals used in an advanced sound system in order
18、 to fully represent the desired audio content; 2 that the loudspeaker positions and configurations described in Annex 1 should be considered for production of advanced sound programmes; 3 that the appropriate number of audio elements1 and loudspeaker layout configurations in programme production sho
19、uld be a choice by agreement between the producer and the recipient in the programme exchange; 4 that consumer interactions with the received audio should be facilitated in the production and broadcast sound system and that its characteristics should be a choice by agreement between the producer and
20、 the recipient in the programme exchange, further recommends 1 that further work should be conducted to provide information about the features of any advanced sound system according to this Recommendation to fulfil the quality requirements of Recommendation ITU-R BS.1909; 2 that only new sound syste
21、ms to be used in broadcasting content production should be added in Annex 1. New sound systems should be a clear expansion from the other sound systems already specified in Annex 1 and their common parts should be as compatible as possible. Such sound systems should be specified by the loudspeaker l
22、ayout (positions and their ranges), the channel labels and their ordering. Annex 1 (normative) Advanced sound system for programme production 1 Introduction The sound system specified in this Recommendation is defined as an advanced sound system which allows the metadata associated with each audio s
23、tream to be static or dynamic for the duration of a programme. This, for example, allows a programme to be represented by elements made by a combination of object signals and channel signals. Channel signals are defined as audio signals that are mixed to a predefined number of channels and accompani
24、ed by metadata being static for the duration of a programme. Each of these channels is associated with a specific loudspeaker. The channel is reproduced by routing the channel to the associated loudspeaker, if present, or is routed to one or more available loudspeakers (e.g. via a 1 An audio element
25、 is considered to be a signal with metadata which is either static for the duration of a programme or is dynamic. This enables the delivery of channel-based, object-based and scene-based content. Rec. ITU-R BS.2051-1 3 channel downmix) so as to best represent playback on the intended loudspeaker. Th
26、e production workflows, broadcasting networks and reproduction systems are defined by a set of loudspeaker positions. Examples are systems according to Recommendation ITU-R BS.775. Object signals are audio signals that, when accompanied by dynamic metadata for the duration of a programme, represent
27、audio elements allowing a renderer to play back the audio objects in a way most appropriate to the playback system and listening environment. An object-based approach also may allow users to interact with the audio content. Object-based elements and channel-based elements can be associated with each
28、 other or exist independently. To allow any combinations of channel or object-based elements, all signals should be accompanied by necessary metadata/descriptors, including time-independent (static) and/or time-dependent (dynamic) spatial position of the desired auditory event. These signals can be
29、reproduced via a configuration of loudspeakers using a variety of rendering and/or mapping techniques. Advanced sound programmes consist of the audio signals and the accompanying metadata. Section 2 specifies requirements for metadata for sound content of the advanced sound system. Section 3 describ
30、es loudspeaker layouts for the systems in production environments. Because a rendering or mapping process is needed for the reproduction of audio signals, the numbers and positions of loudspeakers are required to be well defined. This information enables rendering of the audio signals according to a
31、 predefined loudspeaker configuration in a reproduction scenario. 2 Requirements for metadata/descriptors for sound content of advanced sound system content All audio files and streams used in an advanced sound system will require suitable metadata to accompany them. Unlike simple fixed channel-base
32、d systems where channel ordering is often enough to define the channels, the advanced system will need complete descriptions for all the audio elements used to ensure they are handled correctly. Therefore, a metadata model that has been standardized by a standards organization is required to provide
33、 consistent definitions for the audio. This model should have the following requirements: Contain all information required to reproduce/render a programme in all reproduction scenarios given by Recommendation ITU-R BS.1909 based on a single representation. Be able to describe the format of any chann
34、el-, object- and scene-based audio element. Be flexible enough to describe any combination of elements. The metadata items should be fully described such that they can be used by any renderer. Be specified in an open XML schema to allow the metadata to be represented in XML (as its primary method, i
35、t could of course be translated to other formats such as JSON). Be able to be added to an existing audio file format. To allow commonly used definitions (in particular existing channel-based configurations) to be open and freely accessible from a reference set of definitions. 3 Loudspeaker configura
36、tions for advanced sound system Channel-based signals (including those in an advanced sound system) require a loudspeaker setup where the number and positions of the loudspeakers are well defined. Object-based signals can be reproduced via loudspeakers configured for channel-based signals or additio
37、nal loudspeakers for other advanced rendering systems. 4 Rec. ITU-R BS.2051-1 To ensure the loudspeaker configuration for the advanced multichannel sound system has a consistent definition, a set of parameters have been defined that specify each loudspeaker label, its position, and associated loudsp
38、eaker configurations as described in Table 1: SP Label: denoted by the initial of the layer name and the three-digit azimuth angle. +/SC indicates a loudspeaker pair at the left and right edge of the screen (see Attachment 2 to Annex 1). The centre of the screen should be at an azimuth of 0 degrees.
39、 Azimuth: the azimuth angle expressed in degrees, positive values rotate to the left when facing the front. Elevation: the elevation angle expressed in degrees, positive values go up from the horizontal plane. Rec. ITU-R BS.2051-1 5 TABLE 1 List of possible loudspeaker positions for advanced sound s
40、ystem, identification of the loudspeaker layouts in form of “Upper + Middle + Bottom loudspeakers” SP Label Azimuth Elevation A B C D E F G H I J 0+2+0 0+5+0 2+5+0 4+5+0 4+5+1 3+7+0 4+9+0 9+10+3 0+7+0 4+7+0 M+000 0 0 X X X X X X X X X M+022 +22.5 0 M-022 22.5 0 M+SC Left edge of display 0 X M-SC Rig
41、ht edge of display 0 X M+030 +30 0 X X X X X X X X X X M-030 30 0 X X X X X X X X X X M+045 +45 0 M-045 45 0 M+060 +60 0 X M-060 60 0 X M+090 +90 0 X X X X X M-090 90 0 X X X X X M+110 +110 0 X X X X M-110 110 0 X X X X M+135 +135 0 X X X X X M-135 135 0 X X X X X M+180 +180 0 X U+000 0 +30 X U+022
42、+22.5 +30 U-022 22.5 +30 U+030 +30 +30 X X X U-030 30 +30 X X X 6 Rec. ITU-R BS.2051-1 TABLE 1 (continued) SP Label Azimuth Elevation A B C D E F G H I J 0+2+0 0+5+0 2+5+0 4+5+0 4+5+1 3+7+0 4+9+0 9+10+3 0+7+0 4+7+0 U+045 +45 +30 X X X X U-045 45 +30 X X X X U+060 +60 +30 U-060 60 +30 U+090 +90 +30 X
43、 U-090 90 +30 X U+110 +110 +30 X X U-110 110 +30 X X U+135 +135 +30 X X X U-135 135 +30 X X X U+180 +180 +30 X UH+180 +180 +45 X T+000 +90 X B+000 0 30 X X B+022 +22.5 30 B-022 22.5 30 B+030 +30 30 B-030 30 30 B+045 +45 30 X B-045 45 30 X B+060 +60 30 B-060 60 30 B+090 +90 30 B-090 90 30 B+110 +110
44、30 B-110 110 30 B+135 +135 30 Rec. ITU-R BS.2051-1 7 TABLE 1 (end) SP Label Azimuth Elevation A B C D E F G H I J 0+2+0 0+5+0 2+5+0 4+5+0 4+5+1 3+7+0 4+9+0 9+10+3 0+7+0 4+7+0 B-135 135 30 B+180 +180 30 LFE1 +45 30 X X X X X X X X X LFE2 45 30 X X NOTE The loudspeakers are assumed to be on a sphere.
45、When this is not the case they should preferably be time aligned (at the central listening position) with an accuracy of 100 s. The loudspeaker layouts shown in Table 1 are illustrated in Table 2. 8 Rec. ITU-R BS.2051-1 TABLE 2 Loudspeaker layouts for advanced sound system Lower layer Includes LFE l
46、oudspeakers Middle layer Same level as the listener Upper layer Includes overhead loudspeaker (T+000) Rec. ITU-R BS.2051-1 9 3.1 Loudspeaker positions in production environments As various conditions may need to be considered for the practical design of loudspeaker set-ups in production studios such
47、 as room size, accompanying picture or other constraints, loudspeaker positions may have some azimuth angle and elevation angle variations. To ensure proper adaptation and rendering of channel-based elements, the loudspeaker positions used in the particular production environment should be stored as
48、 part of the metadata according to 2. When the content is transferred to a different reproduction system/location, it should be ensured that the programme is adapted if necessary so that all quality requirements of the advanced sound system are met. The quality requirements are specified in Recommen
49、dation ITU-R BS.1909. However, loudspeakers should be placed within the sectors defined by the azimuth and elevation range as given in Tables 3 to 12 to lessen the sound quality variations by loudspeaker positions differences. A pair of loudspeakers with a nominal azimuth whose magnitude is greater than 45 degrees
