Color in the Cloud: Motion picture and television color grading and finishing on AWS with Baselight
Motion picture and television workloads that require high-fidelity color monitoring such as color grading, VFX compositing, digital intermediate, finishing, and master quality control have typically been precluded from running in the cloud due to the traditional 8-bit 4:2:0 sRGB color space limitations of pixel streaming clients such as Teradici’s CAS and AWS NICE DCV (NICE DCV has recently been enhanced for certain use cases with 4:4:4 10-bit YCbCr support). These post-production activities typically require 10-bit or 12-bit color depth, 4:4:4 or 4:2:2 chroma subsampling, and the correct color space for the deliverable being worked on (typically Rec. 709, Rec. 2020 or DCI-P3). Due to the high bitrates associated with these video signals, it has to date been difficult to efficiently egress them from the cloud without employing lossy codecs such as HEVC, which are unreliable for these use cases. The requirements for a viable cloud-based color and finishing solution are threefold: 1) usage of a visually lossless codec, 2) low-latency encoding, and 3) offloading all computation from the workstation in order to liberate resources for the artist’s experience.
AWS Elemental MediaConnect, a high-quality transport service for live video, and AWS Cloud Digital Interface (CDI), a network technology that allows you to transport high-quality uncompressed video inside the AWS Cloud, provide a solution to the above challenge when repurposed from their intended use cases for broadcast play-out. By leveraging JPEG-XS, “a lightweight image coding system… with compression ratios from 2:1 to 12:1 (or even more) while maintaining lossless quality,” (www.intopix.com) these signals can now be compressed to be suitably transmitted over AWS Direct Connect, AWS VPN, or the open internet while maintaining lossless or “uncompromised” image quality. The transcoding is offloaded to an AWS managed media service so there is no computational or graphics overhead compromising the artist experience. The end result is a viable and scalable solution for high-fidelity, visually lossless color from a cloud provider. MediaConnect currently supports 4:2:2 10-bit JPEG-XS in Rec. 709 and Rec. 2020, with 4:4:4 and 12-bit support in interoperability testing with a release date to be determined.
Color grading on Baselight
AWS is pleased to announce in partnership with FilmLight, Baselight is now enabled with AWS Cloud Digital Interface support. CDI support allows Baselight users in the cloud to connect Amazon Elastic Cloud Compute (Amazon EC2) instances to an on-premises professional grading monitor. Baselight is a color grading and finishing system that provides a comprehensive set of tools for creative finishing of projects across the post-production of film, television, and commercials. FilmLight is headquartered in London, where its research, design, and manufacturing operations are centered. For more information about Filmlight and Baselight, please visit: www.filmlight.ltd.uk.
Decoding with Riedel and Evertz
In order to decode a JPEG-XS signal, a hardware decoder device is required. Several AWS Partner Network (APN) companies have developed decoders compatible with this workflow. The Riedel Fusion 6 device is small enough to sit on a desktop, making it an excellent choice for those concerned about form factor. Several devices from Evertz are also available that have been tested with the Color in the Cloud workflow. For more information about these devices, please visit www.riedel.net or www.evertz.com. These devices are currently available to support 10-bit 4:2:2 workflows with testing underway to support ongoing 4:4:4 and 12-bit enhancements coming to AWS Elemental MediaConnect.
The AWS Color in the Cloud workflow relies on several AWS Elemental products: AWS Cloud Digital Interface (CDI), AWS Elemental MediaConnect, AWS Elemental MediaLive for video encoding and AWS Elemental MediaPackage for content packaging and delivery. CDI, an open-source SDK, can be integrated into any Grading, Digital Intermediate, VFX or Quality Control application in order to transport uncompressed video from the application to the AWS Elemental suite of products. MediaConnect then receives the uncompressed video signal and performs one or both of the following:
1) Primary grading monitoring – JPEG-XS encoding and transport over SMPTE ST 2110-22: MediaConnect is enhanced with the IntoPix JPEG-XS encoding library. This allows for extremely low-latency encoding and compression of the signal into something manageable for transmission over a Direct Connect or even the open internet. An IP based JPEG-XS decoder then converts the signal back to uncompressed video and feeds it over SDI or HDMI to a grading monitor.
2) Secondary over the shoulder view – HEVC encoding and transport over HTTP live streaming: With this option enabled, MediaConnect forks an ancillary signal over CDI to MediaLive. MediaLive encodes HLS variable bitrate streaming variants in either HEVC (h.265) or AVC (h.264) Those variants are then passed to MediaPackage where they are used to form an HLS package. The output of the MediaPackage node is an HLS M3U8 manifest that can then be employed for direct streaming, or incorporated into a companion application. Digital Rights Management (DRM) can be optionally added at this phase.
Each color workstation requires its own discreet AWS Color In the Cloud workflow. The primary user interface monitors are connected to the Amazon EC2 instance via NICE DCV or Teradici CAS. USB peripherals can be passed over an ancillary data channel with Microsoft Windows Clients and Windows-based instances. Authentication can take place via any protocol supported by NICE DCV such as Active Directory or any supported SSO provider.
How to get started
In order to get started with an AWS Color in the Cloud workflow, please contact your AWS Media & Entertainment Account team. You will need a compatible decoder and a supported application such as Filmlight – Baselight. An AWS CloudFormation template will be released soon to our Github (https://github.com/aws-samples) to help automate the deployment.