Prores 2K in Editorial
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ProRes 2K in Editorial WHITE PAPER Date: 6 December 2012 Table of Contents 1. Introduction ................................................................................................................... 3 1.1 ALEXA Capture Aspect Ratios ........................................................................... 3 1.2 Typical Delivery Aspect Ratios ........................................................................... 3 1.3 Sample Footage ................................................................................................. 6 1.4 Framing Charts ................................................................................................... 7 2. Apple Compressor ........................................................................................................ 8 Re-format 2K 16:9 to 1.85:1 US Widescreen DCP (cropped) .................................. 8 Re-format 2K 16:9 (flat) to 2.39 Widescreen ............................................................ 8 Re-format 2K 4:3 anamorphic to 2.39 Widescreen .................................................. 8 3. Blackmagic Design DaVinci Resolve .......................................................................... 9 Re-format 2K 16:9 to 1.85:1 US Widescreen DCP (cropped) .................................. 9 Re-format 2K 16:9 (flat) to 2.39 Widescreen ............................................................ 9 Re-format 2K 4:3 anamorphic to 2.39 Widescreen .................................................. 9 4. Avid Media Composer 6 ............................................................................................. 10 2K 16:9 Footage ..................................................................................................... 10 2K 4:3 Footage ....................................................................................................... 10 Using pre-formatted Material .................................................................................. 11 5. Adobe Premiere CS6 .................................................................................................. 12 2K 16:9 Footage ..................................................................................................... 12 2K 4:3 Footage ....................................................................................................... 13 6. Final Cut Pro 7 ............................................................................................................ 1 4 2K 16:9 Footage ..................................................................................................... 14 2K 4:3 Footage ....................................................................................................... 15 Third Party Plugins ................................................................................................. 15 7. Final Cut Pro X 10.0.5 ................................................................................................. 16 2K 16:9 Footage ..................................................................................................... 16 2K 4:3 Footage ....................................................................................................... 17 ProRes 2K in Editorial – White Paper Page 2 of 17 1. Introduction With the release of SUP 7.0, all ALEXA cameras will be capable of internally recording QuickTime/ProRes 2K files. The ALEXA and ALEXA Plus offer 2K recording in 16:9 aspect ratio while the ALEXA Plus 4:3, ALEXA M and ALEXA Studio can also capture increased vertical resolution with the 4:3 aspect ratio. Capturing with the 4:3 aspect ratio is essential for cinemascope productions as it allows using regular 2:1 anamorphic lenses. Additionally, productions shooting with standard spherical lenses can benefit from the 4:3 "open gate" capture mode. This document provides information on how to correctly re-format ALEXA originated QuickTime/ProRes 2K footage to typical delivery aspect ratios using common editing software or utilities. In many cases, ALEXA footage will also require a conversion from Log C color space for editing, which is not available for all of these tools and should be considered when you plan your dailies and editorial workflow. 1.1 ALEXA Capture Aspect Ratios ARRI ALEXA cameras capture images in either a 16:9 (1.78:1) or a 4:3 (1.33:1) aspect ratio. Other formats, like 1.85:1 US widescreen or 2.39:1 widescreen need to be created in postproduction, typically by adding a letterbox or by cropping the image. 4:3 footage shot with 2x anamorphic lenses is converted to 2.39:1 widescreen using a combination of scaling and cropping. Sensor Mode and Recording Resolution The camera offers three options to select the captured aspect ratio (sensor mode) and recording resolution: 2K 16:9: 2K recording resolution and 16:9 sensor mode produces QuickTime clips with 2048 x 1152 image size, using any ProRes codec at 0.75 to 60 fps. 2K 4:3: 2K recording resolution and 4:3 sensor mode produces QuickTime clips with 2048 x 1536 image size, using any ProRes codec at 0.75 to 48 fps. HD 16:9: HD recording resolution is only available in 16:9 sensor mode. This setting creates QuickTime or DNxHD clips with 1920 x 1080 image size, using any codec in regular speed (0.75 to 60 fps) and any 4:2:2 codec in high speed (60 to 120 fps). 1.2 Typical Delivery Aspect Ratios 2K 16:9 for 1.78:1 (16:9) HDTV When a production is framed and mastered for a 1.78:1 (16:9) aspect ratio, the camera material generally does not need to be converted. The benefit of shooting 2K for a production that will be mastered in HD is the ability to make slight framing-adjustments for 2D productions or alignment correction for 3D productions. ProRes 2K in Editorial – White Paper Page 3 of 17 2K 16:9 for 1.85:1 US Widescreen 1.85:1 for TV or 35mm print: For an HDTV release or release as 35mm print, original camera footage may simply be re-formatted to a 1.85:1 aspect ratio by applying a letterbox or cropping the image height. 1.85:1 DCP: Creating a 1.85:1 release for digital cinema needs some more consideration however. The frame size of a 2K image, cropped to a 1.85:1 aspect ratio, is 2048 x 1108 pixels. The frame size of the 2K DCP container however, is 2048 x 1080 pixels. As a result, a 1.85:1 2K DCP is limited by the height of the 2K container, resulting in a frame size of 1998 x 1080 pixels. There are two methods that deliver the correct frame size for a 1.85:1 DCP. For both methods, there is an individual frame line available in the ALEXA user menu. 1.85:1 DCP – Center Cropped The full 2K frame is cropped to 1998 pixels width and 1080 pixels height. Cropping the image without scaling maintains the original image quality, but influences the field of view (FOV). This is the preferred method and will be described in the application examples below. Frame line: ARRI 1.85 2K DCI 1.85 DCP – Scaled and Cropped The full 2K frame is down-scaled to 1998 x 1124 pixels and then cropped to 1080 pixels image height. Down-scaling typically provides better results than up-scaling. Depending on the scaling algorithm, however, it may introduce an undesirable loss in sharpness. This method will not be further discussed below. Frame line: ARRI 1.85 ProRes 2K in Editorial – White Paper Page 4 of 17 2K 16:9 Flat for 2.39 Widescreen Creating a 2K 2.39:1 DCP from 16:9 footage that was shot on any ALEXA with standard spherical lenses couldn't be easier. Simply crop the 2048 x 1152 image to height of 858 pixels and you are done. The resulting frame size of 2048 x 858 fits perfectly inside the 2K DCP container negating any special treatment or re-formatting of the material in order to work with typical distribution formats. Frame line: ARRI 2.39 2K 4:3 for Anamorphic 2.39 Widescreen Shooting with standard anamorphic lenses on an ALEXA Studio, ALEXA Plus 4:3 or ALEXA M in the 2K 4:3 mode, delivers 33% more capture resolution compared to the same lenses with in a 2K 16:9 aspect ratio. Frame line: ARRI 2.39 Scope 2x The digital cinema standard does not provide for scope projection to optically de-squeeze anamorphic images, therefore the material needs to be mastered with a square pixel aspect ratio: 2.39 2K DCP, 2048 x 858 pixel frame size 2.39 4K DCP, 4096 x 1716 pixel frame size ProRes 2K in Editorial – White Paper Page 5 of 17 De-Squeezing the Image When an anamorphic image is de-squeezed with by a factor of 2, the resulting image will have an aspect ratio of 2.66:1. In order to get to the standard 2.39 aspect ratio, the image then needs to be cropped in width. To see the output from a 2K DCP with a 2.39:1 aspect ratio, the following steps need to be taken on the captured 2048 x 1536 anamorphic frame: 1. Scale the image height to 858 pixels. 2. Scale the image width to 2288 pixels. 3. Crop the image to 2048 pixels width. Most applications offer several adjustments to apply a 2.0 anamorphic de-squeeze for individual clips, a sequence of clips or an entire project. Please refer to your specific applications operations manual for detailed instructions on applying a de-squeeze. The only thing to remember is that in addition to the de- squeeze, the frame needs to be cropped on the sides to bring it to the proper 2.39:1 aspect ratio. 1.3 Sample Footage On the ALEXA downloads webpage www.arri.com/alexa/downloads, we have provided reference frame leader clips that you can be used to test each of the aspect ratio conversions described in this document. ProRes 2K in Editorial – White Paper Page 6 of 17 1.4 Framing Charts There are various combinations of one or more image