How To Deliver Ultra High Definition To Broadcast On A Tv Or Tv (Uhd)

Transcription

1 TECHNICAL STANDARDS SUPPLEMENT FOR DELIVERY OF UHD PROGRAMMES TO BROADCASTER LOGO Version 1.0 This document is a guide to the common technical standard for the delivery of UHD Programmes to BBC, ITV, Channel 4, Sky, and BT Sport. This document is a supplement to the technical standards for programmes that THE BROADCASTER has agreed can be delivered in Ultra High Definition (UHD). It must be read together with the full DPP file delivery document that can be found here; LINK TO BROADCASTER SPECIFIC HD DELIVERY DOC. Please check that you are using the latest version of this document. UHD as a standard is evolving quickly and this document will receive regular updates. Also this document contains several elements that require discussion and agreement with the broadcaster before production begins. Please read through the document and make sure you have had the discussions before you begin production. To ensure the high vision quality thresholds expected from UHD are delivered, it is essential to utilise the highest possible image formats at each point throughout the production workflow. For more information about UHD and UHD production workflows please see the DPP s guides: 10 things you need to know about UHD and UHD Production Workflows, both of which are available to DPP members at:

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5 Contents s Contact Details:... 2 s File Naming Requirements:... 2 s File Delivery Details: Ultra High Definition Overview Ultra High Definition Video UHD Image Format Origination Post- production Film motion or film effect Video Line-up Video Levels (Gamut) Blanking Aspect Ratio Archive Material Use of Non-UHD Material Non- UHD material Film for UHD Production Quality Control Safe Areas for Captions Conversion Frame Rate Conversion Up conversion Single Sensor UHD Cameras (including DSLR) UHD and 4k Cameras UHD Sound Requirements UHD File Requirements File Format Additional Video Constraints Programme Parting (Segmentation) Audio Programme Layout / Format D Delivery Closed captions (Subtitles) Additional Metadata Constraints Appendix 1 Version Control Page 5 of 17

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7 1 Ultra High Definition Overview This document is for the guidance of programme makers who are shooting and mastering in Ultra High Definition (UHD) for delivery to the above s. The International Telecommunications Union (ITU) has defined the world standards for Ultra High Definition Television in ITU-R BT.2020, which defines the overview of the new television standards for the two UHD systems x sometimes referred to as 4k x sometimes referred to as 8k. This document deals with the delivery of x UHD programmes only and uses the term 2 160p. With any new technologies there can be a lot of confusion around terminology especially amongst the consumer manufacturers. The term Ultra High Definition is used by the organisations that make and set international standards and it is the term used to describe a particular set of standards that need to be met. Term Description Standard 4k Digital Cinema Standard usually x K HDR HFR Quad HD UHD Proprietary definition and may describe more than one standard. High Dynamic Range improves the quality of images from black to highlights and speculars. High Frame Rate refers to normal speed images captured at over 60 frames per second. In Europe the maximum is currently 100fps. Four times full HD x at 50 frames per second (1080p/50). Does not have HDR, HFR or WCG options. Ultra High Definition. UHD-1 Sometimes used for Ultra High Definition x Ultra HD WCG Often used for consumer product. Used with 4K by some manufactures (e.g. 4K Ultra-HD). Wide Colour Gamut refers to the extended colours (or Colour Space) that UHD and Digital Cinema offers. The UHD standard includes wider colours often referred to as 2020 Colour and the Digital Cinema Initiative s (DCI) has a P3 colour space. DCI Digital Cinema System Specification None ITU-R* ITU-R BT (10/2015) ITU-R BT (06/2015) ITU-R BT (10/2015) ITU-R BT (10/2015) ITU-R BT (10/2015) * This Recommendation is still under development by the ITU and will augment or replace ITU-R BT UHD is still a very new standard and the end-to-end programme chain is still evolving. There are different interpretations of some of the delivery requirements too, so although this document outlines the requirements for DPP delivery, other co-producers may have their own variations and it s important to clarify what type of versions are required before shooting. Page 7 of 17

8 2 Ultra High Definition Video 2.1 UHD Image Format Material delivered to this specification must be acquired, post-produced and delivered as: x pixels in an aspect ratio of 16:9. 50* or 25* frames per second progressive - known as 2160p/50 or 2160p/25. Colour sub-sampled at a ratio of 4:2:0 or 4:2:2**. The UHD format is fully specified in ITU-R BT (10/2015). * The frame rate must be agreed with the broadcaster before shooting begins. ** Programmes should normally be delivered with 4:2:0 colour, however some broadcasters may require delivery with 4:2:2 colour, and this should be discussed in advance with the broadcaster Origination UHD material can only be originated using progressive scan at 25 or 50 frames per second. Interlace origination is not acceptable. Note; this does not apply for off-speed shooting for slo-mo etc Post-production Electronically generated moving graphics and effects (such as rollers, DVE moves, wipes, fades and dissolves) must be edited so as to prevent unacceptable judder. For 50P deliverables, such effects must be edited at 50 frames per second. If delivering at 25P, this should be discussed with the broadcaster in advance Film motion or film effect Conversion from 50 frames per second to 25 frames per second is permitted provided the frame conversion process is carried out as outlined in Section and an appropriate shutter speed has been used and it has been agreed with the broadcaster. 2.2 Video Line-up Programmes must use the DPP UHD line-up Colour Bars only. A download is available here: Video Levels (Gamut) Although UHD video levels can be measured in a similar way to HD video levels, the requirements vary with the system colorimetry and if a high dynamic range system is used. Section A of the table below gives the black level, peak white and reference white levels for an ITU-R BT.2020 signal. Section B gives values for ITU-R BT.709 (HD) signals if measured in a BT.2020 signal. These tables contain TBD values which will be updated as soon as they are published by the relevant standards bodies. Page 8 of 17

9 Section A ITU-R BT.2020 content R G B Ycr Ycb Fail where any single code value is Black TBD TBD < 4 Peak White TBD TBD > 1019 Ref White TBD TBD TBD TBD TBD - Section B ITU-R BT.709 content inside an ITU-R BT.2020 container (up converted) R G B Ycr Ycb Fail where any single code value is 0% TBD TBD < 4 Peak White TBD TBD > Blanking Ordinarily UHD images should fill the x raster. However, when agreed with the broadcaster before shooting begins, the picture ratio can be wider than 16:9 (meaning that the content is letterboxed ). In these cases the letterbox must be centred vertically in the line frame. 2.5 Aspect Ratio The UHD requirements for Aspect Ratio are the same as for HD. Please see section 2.5 of the Technical Standards For Delivery Of Television Programmes for further information. 2.6 Archive Material Use of archive material must be discussed and agreed with the broadcaster in advance. 2.7 Use of Non-UHD Material Some UHD programmes will contain some material from standard definition and high definition originals, and sources which are not considered to meet UHD broadcast standards. This material is all called non-uhd in this document. To maintain a high standard and meet audience expectations the amount of non-uhd material is limited to 25% of the programme s total duration. Non-UHD material must not be used for large uninterrupted sections of the programme, unless agreed by the broadcaster. This includes archive material. Page 9 of 17

10 2.7.1 Non-UHD material Material acquired using the following methods or formats is considered to be below the ultra high definition standard and will therefore be treated as non-uhd: All SD and HD formats. HD Material usually requires deinterlacing before it can be included in UHD programmes. Most cameras with image sensors under 2/3. Frame based (intra-frame) recording formats below 250Mb/s (25p) and 500Mb/s (50p). Inter-frame based recording formats below 120Mb/s (25p) and 220Mb/s (50p). Film formats below the 35mm format. 2.8 Film for UHD Production Film will not usually be considered for UHD programme production and will be counted as non-uhd content. However 35mm stock (new or archive) scanned at UHD (or 4k and cropped to 3 840) can count as UHD. Super 35mm film ASA100 (or slower) transferred from the negative, may be considered but must be discussed with the broadcaster in advance. 2.9 Quality Control As the UHD standard is new and evolving quality standards need to be discussed with the broadcaster before shooting begins. Initially quality controls will be on a genre by genre basis. As the spec evolves and broadcasters gain a better understanding of it they will be able to provide more guidance in this document Safe Areas for Captions Captions and credits must be clear and legible and must be within the safe areas specified. All UHD font sizes must be legible after down conversion for the SD viewer. There are two primary caption safe areas defined for 16:9 material for UK transmission (EBU R95-1): 16:9 used by all UK DPP broadcasters for captions and in-programme text. 4:3 required for certain programmes/broadcasters for end credits or for programmes distributed internationally. Caption Safe Area Defined as (%) Pixels (inclusive) first pixel numbered 0 16:9 Caption safe 4:3 Caption safe 90% of Active Width 90% of Active Height 67.5% of Active Width 90% of Active Height Page 10 of 17

11 2.11 Conversion This section covers both frame rate and up conversion Frame Rate Conversion When standards converted material is included in a programme, Motion Compensation (sometimes known as Motion Predictive or Motion Vector) standards conversion is required for any conversion from 30p and 60p (/1.001). Speed change is the preferred method of changing between 24fps (including 24/1.001fps) and 25fps standards. Due attention must be given to the audio. Material shot at 50p can be converted to 25p by alternate frame dropping. Care must be taken to minimise judder but frame blending is not recommend. Software standards conversion packages must also use Motion Compensation processing. It is not permitted to use simple timeline conversion. Contact the broadcaster for more information. Below are the recommended processes for frame rate conversion: 24p and 24/1.001p to 25p speed change is the recommended conversion process. 24p and 24/1.001p to 50p speed change plus frame doubling. 30p and 30/1.001p to 25p Motion Compensated Conversion required. 30p and 30/1.001p to 50p Motion Compensated Conversion required. 60p and 60/1.001p to 25p not recommended, speak to broadcaster if required. 60p and 60/1.001p to 50p Motion Compensated Conversion required. Page 11 of 17

12 Content acquired at 24 (24/1.001) fps which has been converted to 60 (60/1.001) fps should first have the repeated frames removed to produce the original frame rate then replayed at 25 fps Up conversion HD and SD material will usually require de-interlacing and frame rate processing during up conversion to UHD. Up conversion from: HD 25psf to UHD 25p no frame rate conversion or de-interlacing required. HD 25psf to UHD 50p frame doubling, no de-interlacing required. HD 25i to UHD 25p not recommended speak to broadcaster if required. HD 25i to UHD 50p de- interlacing and frame doubling. De-interlacing processing should be carried out via a multi-field (five-field or greater) de-interlacer or a motion compensated de-interlacer Single Sensor UHD Cameras (including DSLR) The minimum sensor resolution (pixel count) for single sensor cameras is x (Bayer patterned). Full details are available in EBU R118. Several DSLR cameras have sensors that meet or exceed UHD resolution and are therefore acceptable for specialist use, time-lapse sequences and stop-frame animation but are currently not suitable for use as video cameras. Exceptions may be made for covert shoots or dangerous locations at the discretion of the broadcaster. The broadcaster must agree to the use of DSLR cameras in advance of any shooting UHD and 4k Cameras The EBU divides UHD cameras into two Tiers: UHD-1 Tier 1: have a sensor that can give full UHD resolution and have a pixel count of x in each of R and G and B or, a minimum pixel count of x where Bayer filtering is used. UHD-1 Tier 2: have a sensor resolution that is below full UHD resolution (but greater than HD) and have a minimum sensor resolution of x where Bayer filtering is used. The use of Tier 2 UHD cameras should be checked with the and any UHD co-producer(s) before shooting begins. Page 12 of 17

13 3 UHD Sound Requirements The technical requirements (metering, synchronisation, etc.) for UHD audio are the same as in section 3 of the s HD File Delivery document. LINK TO BROADCASTER HD FILE DELIVERY DOC 4 UHD File Requirements 4.1 File Format The programme must be delivered as one or more files that conform to the AMWA AS-11 X1 Specification ( MXF Program Contribution DPP UHD ). Note: In summary, the key file-format properties of a file that conforms to AMWA AS-11 X1 are: MXF OP1a. AVC / H.264 coded video: o 10-bits per sample o LongGOP (inter coded) or I-Frame (intra coded). Multi-channel Sound Tracks containing 48kHz 24-bit PCM audio. Each Sound Track contains labelling to identify its audio configuration, language, etc. An embedded XML document containing descriptive metadata. A Segmentation Track to identify the in-point and out-point of each programme segment. A continuous Timecode Track. 4.2 Additional Video Constraints The choice of AVC / H.264 coding style (LongGOP (inter coded) or I-Frame (intra coded)) must be discussed in advance with the broadcaster. The AVC / H.264 coded video in each MXF file must have a mean data rate (mean value across the entire file) of at least: LongGOP (inter coded): o 2160p/25: 150Mb/s o 2160p/50: 250Mb/s* I-Frame (intra coded): o 2160p/25: 250Mb/s o 2160p/50: 500Mb/s * Content acquired at 25 fps but delivered as 50 fps in LongGOP to allow for moving graphics may fall below the minimum of 250Mb/s. However, it must not fall below 150Mb/s as required for 25fps acquired content. Note: These data rates are likely to be revised as the standards related to UHD mature and more practical experience is gained. The video signal transfer characteristic(s) must be as defined in one of the following documents: ITU-R BT (10/2015). ARIB STD-B67 (Hybrid Log-Gamma). SMPTE ST 2084 (PQ). The choice of HDR type (and any special arrangements needed for delivery of the file that arise as a consequence) must be discussed in advance with the broadcaster. Page 13 of 17

14 4.3 Programme Parting (Segmentation) Ordinarily each programme should be delivered as a single MXF file. However, when agreed in advance with the broadcaster programmes with several parts may be delivered using more than one MXF file. There must only ever be content from a single programme in each MXF file. The permitted single-part, soft-parting and hard-parting file layouts are as in section 4 of the s HD File Delivery document. 4.4 Audio The MXF file: must only include Sound Tracks that are specified in this document must use Audio Layout Mode 1 (note: this is defined in AS-11 X1). The Sound Tracks listed in the table below must be included in the MXF file as specified. Sound Track Play-out (SoundfieldGroup Label) Number of Audio Channels per Sound Track Content / Purpose (GroupOfSoundfieldGroups Label) Audio Language Number of these Sound Tracks per MXF file Stereo (SMPTE20678StandardStereo) 2 Main Mix - (SMPTE20678MainProgram) Ask broadcaster (_51SoundfieldGroup) 6 Main Mix - (SMPTE20678MainProgram) Same as the Stereo Sound Track above 1 Any additional Sound Tracks that are included in the MXF file must be as specified in the table below. The inclusion of additional Sound Tracks must be discussed in advance with the broadcaster. Page 14 of 17

15 Sound Track Play-out (SoundfieldGroup Label) Number of Audio Channels per Sound Track Content / Purpose (GroupOfSoundfieldGroups Label) Audio Language Number of these Sound Tracks per MXF file Stereo (SMPTE20678StandardStereo) 2 Alternative Mix (such as an additional language) (AlternativeProgram) Ask broadcaster Ask broadcaster or Music & Effects (M&E) (MusicAndEffects) 5.1 (_51SoundfieldGroup) 6 Same as the Stereo Sound Track above (AlternativeProgram) or (MusicAndEffects) Same as the Stereo Sound Track above 1 for each Stereo Sound Track above Stereo (SMPTE20678StandardStereo) 2 Audio Description Mixed with Programme Audio (AudioDescriptionProgramMix) Ask broadcaster Ask broadcaster Mono & Control (AudioDescriptionStudioSignal) 2 Audio Description (AudioDescription) Ask broadcaster Ask broadcaster Exactly one Dolby Audio Metadata Bitstream must be included in the MXF file. This bitstream must contain metadata that is accurate for all of the 5.1 Sound Tracks included in the MXF file. Note: The AMWA AS-11 X1 Specification mandates how a Dolby Audio Metadata Bitstream is embedded in the MXF file. The procedure for delivering audio generated as mono must be discussed with the broadcaster. 4.5 Programme Layout / Format The layout of the programme content must be as in section 4.5 of the s HD File Delivery document except that the legacy layout option is not permitted. Note: this means that the first MXF file for a delivery must start at a timecode of 09:59:30:00 and the first frame of the programme must be 10:00:00: D Delivery Delivery of 3D UHD is not currently defined. UHD may be used for HD Frame Compatible S3D deliverables. 4.7 Closed captions (Subtitles) Closed captions or subtitles must be delivered as a separate file as required by each broadcaster. The separate file must be named identically to the principal MXF file, apart from the filename extension. 4.8 Additional Metadata Constraints The XML document (containing descriptive metadata) embedded inside each AS-11 X1 MXF file must comply with the following additional constraints: Page 15 of 17

16 The Picture_Ratio field must be present. If the programme content does not fill the entire video frame (for example if the content is letterboxed or pillarboxed ) then in the Picture_Ratio field: o Defined_Picture must be used o unless the broadcaster has agreed in advance that Custom_Picture can be used. Page 16 of 17

17 Appendix 1 Version Control UK DPP VERSION VERSION DATE SECTION REQUIRED / INFORMATION UPDATE UK /01/2016 First version of document First version of document BROADCASTER VERSION VERSION DATE SECTION REQUIRED / INFORMATION UPDATE OWNER Page 17 of 17