Launch Technical Guidelines For Ultra High Definition Content

Transcription

1 Launch Technical Guidelines For Ultra High Definition Content

2 Contents 1 Overview Production Cameras Record Formats Film Stock Digital Post Production Guidelines High Definition Commission Ultra High Definition Commission Acquisitions and Acquired Footage Within Commissions Native UHD UHD Film Scan UHD Remastering Of 2K Non-Qualifying-UHD Delivery Format Audio Appendix UHD Terminologies Version Control

3 1 Overview This document details the requirements around Production and provides Post Production Guidelines for Commissions, as well as the expectations of Acquisitions, Acquired content used within Commissions and the Delivery formats. This document is intended to supplement the full Technical Delivery Requirements detailed in the DPP technical specifications. All UHD content must satisfy a Quality Control process specified by Sky. Failure to adhere to these guidelines could result in content being rejected or not qualifying as Ultra High Definition. The advancements in technology around 4k/UHD will necessitate amendments. Please check with Sky to ensure you are using the most up-to-date version of this document. 3

4 2 Production 2.1 Cameras Cameras should comply with the appropriate tiering as defined in the EBU R-118 for UHD: UHD Tier 1 - Full UHD x 2160 output resolution from sensor Minimum Single Sensor size of 1. Single sensor pixel count sufficient that a filtered output (such as Bayer) is equal to or exceeds 3840 X This would nominally require a single patterned sensor of at least 16Mpixels (or approximately 6000 x 3375 pixels) or multiple sensors of R, G and B, each delivering a 3840 X 2160 pixel resolution. UHD Tier x 1620 output format from camera head Single sensor cameras with an imager size approximately the same as the 35 mm film image size. Sensor pixel count has a minimum resolution of 2880 x Multi-sensor cameras with sensors of 2/3 or greater, each sensor having a minimum of 2880 X 1620 picture elements in each of R & G & B. 2.2 Record Formats Film Stock 35mm film where EI is 250 or lower, converted directly to a 3840 x 2160 format and at a rate of 25 frames per a second will be classed as UHD1 Tier Digital Bit Depth A minimum 10-bit processing (but 12 or higher is preferred). Colour Sub-Sampling Capture must be a minimum of 4:2:2 (but 4:4:4 is preferred). Codec Sky may require a specific set of output characteristics that may determine the record codec. Direct data, Raw or Unprocessed camera outputs may be required to maintain full exposure and colour latitude, would deliver the highest quality image and be beneficial for downstream grading. A compressed format may be required for operational needs but can constrain the image grade. As a minimum: AVC Intra based compressed format at no less than 500Mbs for 2160P50 AVC Intra based compressed format at no less than 250Mbs for 2160P25 4

5 3 Post Production Guidelines 3.1 High Definition Commission HD commissions using large sensor UHD, HDR, WCG and / or HFR capable cameras, may require the archive of the original video for future utilisation. If UHD delivery is later required; it should be defined with Sky before delivery as this may also include changes to the HDR, WCG and / or HFR. Workflow, toolsets and storage should be discussed with Sky. The HD image should be produced by scaling from the full UHD image. Where 4K (4096 x 2160) is captured, it must be cropped to UHD (3840 x 2160) before scaling to HD. Cropping a UHD image to HD 1:1 pixel mapped is permitted with qualifying cameras and where a Bayer filter is used, the minimum pixel count should be 2880 x HD deliverables should follow the appropriate DPP Guidelines. 3.2 Ultra High Definition Commission Where the initial commission is UHD, with a HD counterpart, the editorial workflow must be in UHD with the down-conversion performed at the final stage. Where applicable, care should be taken with Dynamic Range, Colour Space and Frame Rate conversion. Post Production techniques and technologies should maintain the highest quality. Where possible the native acquisition format should be utilised and with no transcode process performed by the creation tools. Where this is not achievable, the lowest possible compression ratio (highest possible bit rate) available, by the post production hardware s individual codec, should be used. Artefacts can be created at any point where a recode or transform of the media is performed it is paramount any degradation is minimised throughout the post production chain in order to maintain the highest quality and deliver efficiencies to downstream encoding processes. To avoid the rejection, or the reclassification of your UHD deliverable to HD, formats and workflows should be confirmed with Sky prior to production Current launch requirements are for SDR (Rec. 709). Where a HDR grade has been requested, it should be compliant to ITU-R Recommendation BT.2020 and SMPTE ST

6 4 Acquisitions and Acquired Footage Within Commissions Whilst Native UHD content is limited, it is important that the UHD content we supply meet the expectations of being noticeably better image than HD, on the same UHD screen. The below provides further information on formats which Sky qualifies as UHD. It is the content supplier s responsibility to confirm to Sky, prior to delivery, which category content comes from: Native UHD, UHD Film Scan or UHD Remastering Of 2K DIs. 4.1 Native UHD Native UHD is defined as content recorded on cameras meeting the minimum requirements of UHD1 Tier 2 as defined by EBU R- 118, with this native horizontal resolution of 3084 or greater, retained throughout post production and through to delivery. Cameras that do not qualify with EBU R-118 as UHD must be discussed with Sky. 4.2 UHD Film Scan The definition captured by film stock can vary greatly depending on many factors, such as era, film speed, number of perfs and its condition from storage. To achieve the highest quality, scanning of film should start with the original print. The scanning must be at either 4k/UHD resolutions, without rescaling that would introduce pixel interpolation. 4K scans must be cropped to UHD 1:1 pixel mapped with mineral impact to the intention of the framing and subject within it. Higher resolution scans, with the intention to oversample, are acceptable but care must be taken to ensure this does not result in an otherwise softer image than a 4k/UHD scan. If oversampling is intended, it is recommended to scan at a 4:1 pixel ratio (8K). Each frame should be digitally treated to remove contaminations and other defects (e.g. dirt and scratches) and care should be taken in controlling noise and sharpening, as well as colour and contrast improvements. Eligible UHD film stock would be of 3 perf or greater, of an ISO of 250 or less and without processes applied which would reduce definition (e.g. push processing/uprating or neg/print crops/push-ins). Age of film stock, condition from storage and level of restoration also influences the picture quality and all play a part in whether the resulting image qualifies as UHD. In the scenario where some of the this film stock information is difficult to ascertain, a variable of film stock used or there is uncertainty to whether the resulting image quality would qualify as UHD, Sky should be informed of the known factors (e.g. cameras, shooting format, resolutions, post-production processes, percentage of non-uhd footage etc.) and samples can be submitted for review ahead of delivery. 4.3 UHD Remastering Of 2K Remastering of content from a Progressive Frame, 10 Bit or greater, and 2K resolution or greater, may be accepted as UHD. This would be subject to the remastering process, agreement from Sky and a QC assessment. Care should be taken in controlling noise and sharpening, as well as colour and contrast improvements. 4.4 Non-Qualifying-UHD Different shooting environments (e.g. GoPros for crash-cam type shots) and intended styles (faster film speed for some desired effects / lighting environment) will present exceptions where non-qualifying-uhd content is permitted within a UHD deliverable. To ensure the UHD content retains consistently high quality, a maximum of 25% non-uhd footage is permitted and where this is utilised within a Commission; it should sit within the editorial context of the program and not exceed 5 minutes, in any 15 minute period. Whilst CGI is predominantly rendered in 2k, its usage is not limited to the above constraints with Acquisitions and its usage with commissions should be discussed with Sky. 6

7 5 Delivery 5.1 Format Launch delivery formats and methods must be discussed with Sky ahead of delivery, alternatives to the below may be permitted as an exception. Bit Depth 10 Colour Sampling 4:2:2 Colour Space REC. 709 (gamut levels within threshold defined by with EBU R103) Scan Delivery Format Progressive Frame IMF Application 2e / JPEG fps or greater) - intended for Movies, preferable frame rate is 25fps. IMFs may be accepted for the delivery of Commissioned content but at a higher bitrate. XAVC Intra 25fps or greater / 50fps or greater) ProRes HQ ProRes LT Requirements for Native, Uncompressed, RAW files or non-linear files, for commissioned content, should be discussed with Sky Audio With the exception of movies for platforms without commercial breaks, audio must be mixed to comply with the EBU R128. Movie content intended for channels or platforms without commercial breaks (e.g. a movie-only channel or VOD exclusive movie content) should be supplied with the same audio mix as the consumer DVD/Blu-Ray (often the Nearfield Mix), which may not necessarily be R128 compliant. If the commission contains dubbing of foreign languages, please check with Sky to confirm the delivery method of the foreign dialogue. Audio, which is delivered as discrete tracks, as oppose to Soundfield Groups, should have its channels allocated to the following tracks. 01 Main Stereo L 02 Main Stereo R 03 M&E Stereo L 04 M&E Stereo R 05 Main 5.1 Front L 06 Main 5.1 Front R 07 Main 5.1 Centre 08 Main 5.1 LFE 09 Main 5.1 Surround L 10 Main 5.1 Surround R 11 M&E 5.1 Front L 12 M&E 5.1 Front R 13 M&E 5.1 Centre 14 M&E 5.1 LFE 15 M&E 5.1 Surround L 16 M&E 5.1 Surround R 7

8 6 Appendix 6.1 UHD Terminologies Ultra High Definition (UHD) Broadcast and Consumer TV UHD Format Resolution of 3840 Horizontal pixels by 2160 Vertical pixels ITU-R Recommendation BT.2020 (AKA Rec. 2020) Quad Full HD (QFHD) 4 HD 1080P50 quadrants compiled to a single UHD frame ITU-R Recommendation BT.709 (AKA Rec. 709) HD 4K 2K Broadcast and Consumer TV UHD Format Can be used to describe a resolution of 1920 x 1080 ITU-R Recommendation BT.709 (AKA Rec. 709) This Format is not classified as UHD when up converted to the UHD format. Cinema UHD format Resolution of 4096 Horizontal pixels by 2160 Vertical pixels Defined in SMPTE ST 2048 Cinema format Term can refer a number of resolution including 2048 x 1080, 2048 x 1556 and 2440 x 1810 High Dynamic Range (HDR) HLG = HLG grade based on BBC variable curve PQ = HDR 10 SMPTE 2084 HDR is still under review Standard Dynamic Range (SDR) The dynamic range commonly used on consumer TVs ITU-R Recommendation BT.709 (AKA Rec. 709) High Frame Rate (HFR) For UK this is currently 50 progressive frames per a second Wide Colour Gamut (WCG) Extended colours space ITU-R Recommendation BT.2020 (AKA Rec. 2020) Frames Per A Second (FPS) The number of full frames displayed per a second. Progressive The creation and transport of an image acquired as a single full frame For the UK this may be 25 or 50 frames per second All UHD content must be acquired in a Progressive manner Native UHD Recorded electronically at the full pixel count of 3840 X 2048 This native resolution must be retained throughout post production, through to delivery, to qualify as Native UHD Eligible UHD Film 35mm or grater 3 perf or greater IE of 250 or less Without processing which would reduce definition (e.g. push processing/uprating or neg crops/push-ins) 16mm / Super 16mm will not qualify as Eligible UHD Film True UHD Native UHD or UHD/4K Eligible Film Commission Content Sky has financed to be made. Acquisition Pre-made content which Sky has licenced the use of. 8

9 6.2 Version Control Version Date Section Update 1.0 May Initial publication 1.1 June Correction made to UHD Tier 2 camera resolution. Document Owner: Contributors: Chris Johns Ashley Ross Kevin McCue 9