1、Measurement methods High dynamic range video PD IEC/TR 62935:2016 BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06National foreword This Published Document is the UK implementation of IEC/TR 62935:2016. The UK participation in its preparation was entrusted to Techni
2、cal Committee EPL/100, Audio, video and multimedia systems and equipment. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct
3、application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 93495 7 ICS 33.160.40 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Standards Policy and St
4、rategy Committee on 31 August 2016. Amendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD IEC/TR 62935:2016 IEC TR 62935 Edition 1.0 2016-07 TECHNICAL REPORT Measurement methods High dynamic range video INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.160.40 ISBN 97
5、8-2-8322-3517-1 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. PD IEC/TR 62935:2016 2 IEC TR 62935:2016 IEC 2016 CONTENTS FOREWORD . 3 INTRODUCTION . 5 1 Scope 6 2 Normative references. 6 3 T
6、erms and definitions 6 4 Overview . 7 4.1 Historical background 7 4.2 Scene versus display ranges . 7 4.3 HDR ranges 8 5 HDR standards and related activities 9 5.1 SMPTE . 9 5.1.1 10E study group on HDR ecosystem . 9 5.1.2 ST 2084:2014 9 5.1.3 ST 2086:2014 9 5.1.4 ST 2036-1 9 5.2 CEA-861.3 9 5.3 HDM
7、I 2.0a 10 5.4 ITU-R 10 5.4.1 BT.2020-1 10 5.4.2 HDR 10 5.5 ICDM 10 6 HDR content 10 6.1 General . 10 6.2 Cinema . 10 6.3 Ultra HD Blu-ray 11 6.4 Streaming media . 11 6.4.1 Amazon . 11 6.4.2 Netflix 11 6.4.3 Other . 11 6.5 Broadcast . 11 6.6 Redistribution platforms . 11 7 Measurement of HDR 12 7.1 G
8、eneral . 12 7.2 Peak white 12 7.3 Full-screen black . 12 7.4 Contrast ratio 13 7.5 Colour Gamut 13 7.6 White point 13 7.7 Other 13 Bibliography . 14 PD IEC/TR 62935:2016IEC TR 62935:2016 IEC 2016 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ MEASUREMENT METHODS HIGH DYNAMIC RANGE VIDEO FOREWORD 1) T
9、he International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical a
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18、f, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that som
19、e of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. The main task of IEC technical committees is to prepare International Standards. However, a technical committee may propose the publication
20、of a technical report when it has collected data of a different kind from that which is normally published as an International Standard, for example “state of the art“. IEC TR 62935, which is a technical report, has been prepared by IEC technical committee 100: Audio, video and multimedia systems an
21、d equipment. The text of this technical report is based on the following documents: Enquiry draft Report on voting 100/2642/DTR 100/2703/RVC Full information on the voting for the approval of this technical report can be found in the report on voting indicated in the above table. This publication ha
22、s been drafted in accordance with the ISO/IEC Directives, Part 2. PD IEC/TR 62935:2016 4 IEC TR 62935:2016 IEC 2016 The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC website under “http:/webstore.iec.ch“ in the data re
23、lated to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. PD IEC/TR 62935:2016IEC TR 62935:2016 IEC 2016 5 INTRODUCTION The market for the producti
24、on and delivery of moving images has transitioned from film through analogue standard-definition video through digital HD video and now to 4K Ultra HD video. As the increase in resolution continues to 8K, the opportunity exists to increase the dynamic range of the video, including brighter peak lumi
25、nance levels. This, in conjunction with wide colour gamut, increases the volume of possible levels and colours, resulting in more realistic and hyper-realistic presentations. IEC TC 100 AGS SS9 (HDR) has identified a standardization opportunity related to measurement methods and test signals for HDR
26、 video. This Technical Report sets the groundwork for such an activity. PD IEC/TR 62935:2016 6 IEC TR 62935:2016 IEC 2016 MEASUREMENT METHODS HIGH DYNAMIC RANGE VIDEO 1 Scope This document introduces the concept of High Dynamic Range (HDR) video, lists some of the related standards and activities, p
27、rovides information about HDR in the marketplace, and proposes areas of HDR measurement that could be standardized. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated referenc
28、es, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. There are no normative references in this document. 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO
29、and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at http:/www.iso.org/obp 3.1 high dynamic range HDR span of image luminances that is larger than normall
30、y possible for standard, high definition, and ultra HD video 3.2 standard dynamic range SDR span of image luminances that is normally possible for standard and high definition video Note 1 to entry: Standard definition, high definition, and ultra HD video systems are normally capable of producing lu
31、minances of 10 times that of an average mid-tone at the top (white) end of the range, and of 0,01 times that of an average mid-tone at the bottom (black) end of the range. 3.3 wide colour gamut WCG range of colours in a colour space that covers a large percentage of visible colours EXAMPLE ITU-R BT.
32、2020 2 1is considered to provide WCG while BT.709 3 does not. _ 1Numbers in square brackets refer to the Bibliography. PD IEC/TR 62935:2016IEC TR 62935:2016 IEC 2016 7 4 Overview 4.1 Historical background Still and moving pictures were initially captured and displayed with chemical processes, typica
33、lly on film. The dynamic range varied by process and was limited by the maximum density achievable on the reproduction medium for representation of dark areas and by the minimum density achievable on the reproduction medium in representation of bright areas. Though there are hard limits with this te
34、chnology, the processes involved resulted in the limits being approached gradually, with dynamic range expansion in the mid-tones, and dynamic range compression at the extremes. Electronic images were initially captured and displayed using analogue means. Electronic noise limits the representation o
35、f dark areas and defined limits can clip the bright areas. Though a wire can carry much more than a 1 V signal (which represents 100 % white in some systems), various equipment in the processing chain might apply a hard clip. There is no natural compression as the signal approaches the white limit.
36、Dynamic range compression is generally performed in the camera or in post-production with specialized equipment. Today, most image capture, storage, and processing is based on digital technology. Dark details are limited by the noise and quantization error. White levels have a hard limit at the defi
37、ned maximum white code value. Similar to analogue electronic techniques, dynamic range expansion in the mid-tones and compression at the extremes is performed by in-camera processing or in post-production. Picture levels were standardized during the analogue time frame. Peak white for displays was d
38、efined as 48 cd/m 2for the cinema and 100 cd/m 2for video presentation in mastering suites under controlled, low-level lighting conditions. These standardized levels were retained during and after the transition from analogue to digital equipment and techniques. NOTE Consumer televisions have higher
39、 peak luminance, typically around 350 cd/m 2 , in order to allow for bright viewing conditions. In order to optimize the use of signal levels, a gamma curve is applied between signal and display. This was done naturally by cathode ray tube displays and is done electronically in typical flat panel di
40、splays. The gamma equation is as follows: in out AV V = ITU-R Recommendation BT.1886 1 2 defines gamma ( ) as 2.4 and screen luminance for white as 100 cd/m 2for standard dynamic range high definition video. 4.2 Scene versus display ranges Images are captured in a variety of conditions from the dark
41、 reaches of Pluto to the intense light levels of the sun. The captured ranges of these images are normalized by controlling exposure levels. The high dynamic range system covered by this document is not intended to capture Pluto and the Sun at a single exposure image; however, an HDR system allows t
42、he captured range of those two separate images to include deeper black levels above the noise level and brighter white levels without clipping. An HDR system preserves those larger ranges through display to the viewer. This requires higher bit-depths, displays capable of higher luminance peaks, and
43、carefully designed transfer functions to optimize the relationship between signal and presentation. _ 2Numbers in square brackets refer to the Bibliography. PD IEC/TR 62935:2016 8 IEC TR 62935:2016 IEC 2016 In essence, HDR relates to a system and signal definition that can represent an increased dar
44、k to bright range of a high dynamic range display, rather than trying to capture the full- range of extreme luminance differences found in nature. A display with an increased dynamic range enables a fuller representation of the scene. Today, highly controlled scene lighting is generally used to keep
45、 faces bright, limit overly bright areas that would otherwise be “blown out”, and to light dark areas such that textures remain visible. In addition, electronic dynamic range compression is used to ensure that the information is well-represented by the signal. In naturally lit scenes, such as in spo
46、rts, news, and documentaries, heavy dynamic range compression is often used and/or the signal is clipped, given that the lighting is generally not under the control of the content creator. For todays SDR video systems, the content creator shall balance clipping at the extremes with making images dul
47、l through strong lighting or electronic compression. For high-value content, adjustment of the dynamic range and colours can be controlled separately in various spatial regions of each frame by using dynamic masks. Image grading with dynamic masks can be complex and time consuming and is not practic
48、al in some situations, like live sports broadcasts and electronic news gathering. On the other hand, with an HDR system, the content creator can preserve bright, specular highlights, source lighting, and sunlit areas with minimal clipping while also presenting well- displayed faces and deeply dark t
49、extures. The result can be a more compelling visual experience than offered by SDR systems. The result can also be more representative of reality and can reduce the need for time-consuming, manual adjustments. 4.3 HDR ranges There are practical limits on peak white levels, related to viewers and to displays. Excessively high peak luminance levels could be uncomfortable for the viewer and implementation of such a display might be impractical. For these reasons, there is no nee
