1、 Report ITU-R BT.2053-2(11/2009)Large screen digital imageryBT SeriesBroadcasting service(television)ii Rep. ITU-R BT.2053-2 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication
2、 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 Conferences and Radiocommunic
3、ation 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 statements and licensing declaration
4、s 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 Reports (Also available online at http:/www.itu.int/pu
5、bl/R-REP/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 services P Radiowave propagation RA
6、 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 Note: This ITU-R Report was approved in English by the Study Group under the proce
7、dure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2010 ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rep. ITU-R BT.2053-2 1 REPORT ITU-R BT.2053-2 Large screen digital imagery (Question ITU-R
8、 15/6) (2005-2006-2009) Foreword This Report has been prepared by Radiocommunication Study Group (SG) 6 and Radiocommunication Task Group (TG) 6/9, and contains information gathered from a number of external sources as well as from Radiocommunication TG 6/9. The terminology used throughout this Repo
9、rt is not consistent, other bodies such as, Society of Motion Picture and Television Engineers (SMPTE)1, and European Digital Cinema Forum (EDCF)2and technical publications, have used different terms in their deliberations to the terms adopted by Radiocommunication TG 6/9 in defining large screen di
10、gital imagery (LSDI). Further, it is not appropriate to draw comparisons between various definitions. This Report retains the original text provided by the various sources. The reader is cautioned not to draw any conclusions on the eventual adoption of terminology within this evolving industry. 1 In
11、troduction Radiocommunication TG 6/9 was formed by SG 6 in 2002 as a result of the adoption of ITU-R Question 15/6 “Digital cinema (D-Cinema) broadcasting”. Dr Joseph Flaherty of the North American Broadcasting Association (NABA) chaired the task group. Radiocommunication TG 6/9 held its first meeti
12、ng in March 2002. Some questions were raised concerning the scope of the task group; and it was concluded that aspects specifically relating to motion pictures (movies) should be based on standards developed by the motion picture expert groups. As a result, a revised Question was prepared and subseq
13、uently adopted, and the term “large-scale digital imagery (LSDI)” has been employed to describe the area of work of the task group. The revised Question is attached as Appendix 1. This Report is intended to supplement the set of Recommendations prepared by the task group, giving a brief summary of L
14、SDI and the work of the task force and providing detailed information on LSDI technology and LSDI applications. A progress report on standardization for digital cinema is also included. 2 What is LSDI? Large screen digital imagery (LSDI) is a family of digital imagery systems applicable to programme
15、s such as dramas, plays, sporting events, concerts, cultural events, etc., from capture to large screen presentation in high-resolution quality in appropriately equipped theatres, halls, and other venues. There may be many types and sizes of LSDI venues and audiences, but audiences larger than typic
16、al family viewing, using display systems larger than those that would normally be considered for a home environment, characterize LSDI. 1See digital cinema Specification V1.0 as submitted to the SMPTE at . 2See definitions of the EDCF four levels in 1 of Chapter 3 of Part 2. 2 Rep. ITU-R BT.2053-2 L
17、SDI became practical as a result of the development of electronic display systems suitable for viewing by an audience of significant size. Such display systems evolved in a number of areas. Some systems were designed to display very large albeit relatively low resolution images for viewing at long d
18、istances by very large audiences, such as in sports venues. Other systems were developed by the computer and audio/video (A/V) industries to facilitate presentation of electronic slides to smaller audiences in business environments. Eventually, these developments led to display systems that could pr
19、oduce an audience experience comparable to that delivered by projection of 35 mm motion picture film, and the concept of digital cinema was born. It soon became apparent that the evolving technologies could serve two very different areas of requirements. The motion picture industry intends to develo
20、p systems to replace the distribution and projection of 35-mm film prints. In this area it is vitally important to preserve characteristics of film that differentiate it from television, including extended colour gamut and very large contrast range. These considerations meant that the motion picture
21、 industry needed to undertake extensive studies based on the unique requirements of the business. Another area of great interest is the use of LSDI to permit presentation of television programming to large audiences, such as in theatres. Obvious examples are sports events and concerts or other stage
22、 productions. In this area it is essential that the characteristics of LSDI systems be closely matched to the television systems that are likely to be used to acquire the programmes 3 LSDI venues LSDI is suited to any venue where electronically delivered moving images are to be displayed for an audi
23、ence. Such venues may range from community television halls to stadium environments while the audience size may range from few persons to many tens of thousands. Some of the many possible LSDI venues, and ways in which they may be used, are discussed in Chapter 7 of Part 1. The work of the task grou
24、p focused largely on LSDI for theatrical environments. It was recognized that even this classification may include venues of many sizes and characteristics, but emphasis was given to venues where audiences could receive a “big-screen” experience. The LSDI sound system should have characteristics com
25、mensurate with this, so as to enhance the overall audience experience. Generally, the LSDI experience should represent a significant enhancement over conventional television, even large-screen television. Recommendation ITU-R BT.1690 describes such a theatrical environment in perceptual terms. 4 Vid
26、eo signal formats for LSDI The task group developed two Recommendations for baseband video formats for LSDI. Recommendation ITU-R BT.1680 recommends the use of Recommendation ITU-R BT.709 (1 920 1 080 at various frame rates, interlaced and progressive) and Recommendation ITU-R BT.1543 (1 280 720 at
27、59.94 Hz, progressive). It further recommends that for an expanded hierarchy of LSDI digital image formats for future LSDI applications that may require certain resolution and scanning formats that go beyond current technical solutions or those image formats used in other applications a hierarchical
28、 relationship with existing Recommendations be retained. For applications where high-definition signals are not available, Recommendation ITU-R BT.1689 recommends the use of Recommendation ITU-R BT.601 (720 576/480 at 50/59.94 Hz). Rep. ITU-R BT.2053-2 3 Programme material for LSDI will normally nee
29、d to be compressed for delivery to the venue; Recommendation ITU-R BT.1687 recommends the use of MPEG-2. This Recommendation suggests that LSDI applications will generally need higher bit rates than those used for delivery of television to the home. Recommendation ITU-R BT.1687 recommends “MPEG-2 in
30、terframe bit-rate reduction at MPHL (HiQ) and at a minimum video net bit rate of the order of 20 Mbit/s should be preferred in the short term, for real-time distribution of LSDI programmes for their theatrical presentation.” 5 Audio for LSDI The task group recognized that high-quality, multichannel
31、audio is an essential component of presentation in an LSDI environment. Recommendation ITU-R BT.1688 recommends a delivery of 5.1 channel audio as part of LSDI programming, and the use of 48 kHz sampling at a minimum 16-bit resolution, and the use of either baseband PCM, AC-3, or AAC encoding. Some
32、LSDI applications for a large theatrical environment may need multichannel sound systems that can reproduce the sound sources, which are localized at a higher position over the listener, and vertical and horizontal movements of sound sources. Several multichannel sound systems are currently applied
33、or studied for a theatre with a large screen, and some of them have loudspeakers arranged above and around the viewer. 6 Quality considerations for LSDI Audiences will have high expectations for LSDI and the quality of the presentation will be critical to success in many areas. Recommendation ITU-R
34、BT.1662 discusses issues of post-processing headroom in the LSDI chain. Recommendation ITU-R BT.1663 addresses display quality; Recommendation ITU-R BT.1686 covers measurement of image parameters, and Recommendation ITU-R BT.1721 makes recommendations for measurement of perceptive image quality. Rec
35、ommendation ITU-R BT.1679 addresses subjective evaluation of audio quality in LSDI environments. A study on psychological effects of wide-screen display systems confirms that wider viewing angles generate higher “sensation of reality”. It also implies that LSDI with higher resolution than HDTV would
36、 be needed for applications that require a higher “sensation of reality”. On the other hand, it is known that decreases of comfortableness would arise when the viewing position is too close to wide-screen images. Based on such results, parameter values for expanded hierarchy of LSDI systems such as
37、display size, viewing distance and spatial resolution might be determined. 7 Delivery of LSDI content Traditional broadcast channels such as terrestrial transmission will not generally deliver LSDI content. The large screen will make impairments such as compression artefacts more apparent, and lower
38、 compression ratios will normally be needed for LSDI. Real-time delivery of LSDI will normally use broadband terrestrial circuits or satellite systems. Recommendation ITU-R BT.1727 addresses these forms of delivery. Non-real-time delivery may use similar circuits, or may use tapes or disks. Recommen
39、dation ITU-R BT.1694 makes recommendations for the use of videocassette recordings. 4 Rep. ITU-R BT.2053-2 8 LSDI technologies and implementations Current and future LSDI technologies are both discussed in Part 1, which consists of eight Chapters related to the various components of the LSDI chain.
40、Part 2 includes available information on the status of implementations of LSDI applications around the world and future LSDI trends. It is divided into three Chapters, one for each region covered by relevant investigations, namely America (North and South), Asia and Europe. 9 Digital cinema A progre
41、ss report on standardization for digital cinema will eventually be included, as Part 3 of this Report. 10 Recommendations The Recommendations developed by the task group are listed below in Table form, and with a brief summary of the subject matter. LSDI application for presentation in a theatrical
42、environment Recommendations already developed by Radiocommunication TG 6/9 Rec. ITU-R Title BT.1662 General reference chain and management of post-processing headroom for programme essence in large screen digital imagery applications BT.1663 Expert viewing methods to assess the quality of systems fo
43、r the digital display of large screen digital imagery in theatres BT.1664 Representation of various image aspect ratios into the image of large screen digital imagery applications that use a 16:9 raster BT.1665 Considerations for colour encoding and spatial resolution for large screen digital imager
44、y display BT.1666 User requirements for large screen digital imagery applications intended for presentation in a theatrical environment BS.1679 Subjective assessment of the quality of audio in large screen digital imagery applications intended for presentation in a theatrical environment BT.1680 Bas
45、eband imaging format for distribution of large screen digital imagery applications intended for presentation in a theatrical environment BT.1686 Methods of measurement of image presentation parameters for large screen digital imagery programme presentation in a theatrical environment BT.1687 Video b
46、it-rate reduction for real-time distribution of large screen digital imagery applications for presentation in a theatrical environment BS.1688 Baseband sound system and audio source-coding at delivery interfaces of large screen digital imagery applications BT.1689 Guidelines on the presentation in l
47、arge screen digital imagery environments of programmes that are provided in image formats conforming to Recommendation ITU-R BT.601 BT.1690 Assumed characteristics of venues intended for large screen digital imagery programme presentation in a theatrical environment Rep. ITU-R BT.2053-2 5 Rec. ITU-R
48、 Title BR.1694 Videocassette recording formats for international exchange of large screen digital imagery programmes intended for presentation in a theatrical environment BT.1721 Objective measurement of perceptual image quality of large screen digital imagery applications for theatrical presentatio
49、n BT.1727 Terrestrial and satellite delivery of programme material to large screen digital imagery venues BS.1734 Basic performance requirements for the sound components of large screen digital imagery applications for presentation in a theatrical environment Recommendation ITU-R BT.1662 General reference chain and management of post-processing headroom for programme essence in large screen digital imagery applications This Recommendation specifies a general reference chain that should be used to study post-processing headroom management for typical LSDI app
