1、 Recommendation ITU-R BS.1864(03/2010)Operational practices for loudness in the international exchange of digital television programmesBS SeriesBroadcasting service (sound)ii Rec. ITU-R BS.1864 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and eco
2、nomical use of the radio-frequency spectrum 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 b
3、y World and Regional Radiocommunication Conferences 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 u
4、sed for the submission of patent statements 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. S
5、eries of ITU-R Recommendations (Also available 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, radiodet
6、ermination, amateur and related satellite 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 S
7、atellite news gathering TF Time signals and 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, 2010 ITU 2010 All rights reserved. No part of this pu
8、blication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R BS.1864 1RECOMMENDATION ITU-R BS.1864 Operational practices for loudness in the international exchange of digital television programmes (Question ITU-R 58/6) (2010) Scope This Recommendation specifies
9、 operational practices intended to improve the consistency of loudness of digital television programmes that are intended for international exchange. These practices apply to the production of those programmes. They do not apply to the distribution or emission of broadcast programmes. The ITU Radioc
10、ommunication Assembly, considering a) that the audience of digital television programmes enjoys programmes better when their loudness is reasonably uniform, irrespective of different programme sources and different programme types; b) that it would be very desirable if reasonable consistency in the
11、loudness of sound programmes, and of sound accompanying television programmes, were also achieved on internationally exchanged programmes; c) that Recommendation ITU-R BS.1726 specifies use of either 18 dBFS or 20 dBFS for “alignment level”, but that “alignment level” does not directly correspond to
12、 audio loudness; d) that Recommendation ITU-R BS.1770 Algorithms to measure audio programme loudness and true-peak audio level, specifies a method for the measurement of audio programme loudness; e) that Recommendation ITU-R BS.1771 Requirements for loudness and true-peak indicating meters, specifie
13、s the requirements for loudness meters that employ the algorithms specified in Recommendation ITU-R BS.1770, thus enabling the worldwide use of loudness meters that behave in a consistent manner and provide a consistent indication of loudness on the same programme, irrespective of programme content;
14、 f) that one programme element that is of concern to the audience in programmes that are predominantly dialogue is the loudness of dialogue, and that this should desirably be uniform in internationally exchanged programmes; for other types of internationally exchanged programmes, such as short spots
15、, or programmes featuring important non-dialogue subject matter, it is the loudness of the full programme mix that is of most concern to the audience; g) that some audio systems include metadata for controlling loudness and others do not, further considering a) that reducing inter-programme audio lo
16、udness differences may improve audience satisfaction; b) that practical measurement techniques, and anticipated consequences of the way metering algorithms are implemented, suggest that a difference may be anticipated of up to 2 dB between measurements conducted on the same content by different faci
17、lities, and that such variations are anticipated and acceptable in practice; Rec. ITU-R BS.1864 2c) that studies have shown that listeners can comfortably tolerate some loudness variation as long as the loudness does not deviate from a “comfort zone”, which is a loudness window of approximately +3 t
18、o 5 dB relative to the desired loudness, recommends 1 that loudness measurements should be made, including all audio channels, in conformance with Annex 1 of Recommendation ITU-R BS.1770; 2 that for international exchange of digital television programmes, when metadata is employed to indicate the lo
19、udness of the programme, the metadata value should correspond to the average loudness of the full programme mix, or to the average loudness of the normal dialogue component whichever is deemed appropriate by the programme provider; 3 that for international exchange of digital television programmes,
20、when metadata is not employed to indicate the loudness of the programme, the measurement of average loudness should be made on the full programme mix, or on the normal dialogue component whichever is deemed appropriate by the programme provider; 4 that for the international exchange of digital telev
21、ision programmes, the target loudness should be 24 LKFS; 5 that Notes 1 and 2 are to be regarded as part of this Recommendation, and further recommends 1 that, variations of up to 2 dB in measured loudness should be anticipated and, due to the “comfort zone” mentioned in further considering c), shou
22、ld be considered acceptable as long as there is no consistent operation at either extreme; 2 that due account be taken of the fact that there may be occasions where a departure from the provisions of this recommendation is necessary or desired for various reasons, such as overriding creative require
23、ments, legacy programmes, or the need to match loudness of heavily compressed sound recordings. NOTE 1 The algorithm specified in Recommendation ITU-R BS.1770 for loudness measurement is an integrating measure: a manual or automatic gating function should be used, pausing the integration during quie
24、t periods. It should be noted that, in the absence of a formal definition of the gating function, slight variations in measured loudness values might be observed. The incorporation of a gating function into Recommendation ITU-R BS.1770, to pause the integration during quiet periods, is currently under study. NOTE 2 “Normal” dialogue is that which is spoken in a normal level of speaking voice, that is, not shouting or whispering.
