GUEST BLOG BY DJ Rahming, Brandon Lindauer, Mike Owen, and Sean Wallitsch 

As high-performance, real-time post-production workflows such as color grading and finishing migrate to the cloud, the ability to view reference quality video on appropriate local display devices is critical. 

In addition, as teams become more and more comfortable working at a distance, creative decision-makers still expect to have a real-time, high-quality view to provide over-the-shoulder feedback, wherever they might be located. 

This creates a new set of challenges to satisfy post-production workflows. 

Autodesk Flame, Streambox Spectra VM, and Colorfront Streaming Server now support AWS Cloud Digital Interface (AWS CDI). With this support and the ultra-high fidelity workflows announced last year for color grading in the cloud and AWS Elemental MediaConnect, there is a growing list of options to solve these challenges, tailored to suit a variety of requirements. 

What is AWS CDI? 

AWS CDI is a network technology that allows you to transport high-quality uncompressed video inside the AWS Cloud, with high reliability and network latency as low as 8 milliseconds. Workloads that require high-performance connectivity and uncompressed live video have historically been deployed on-premises using Serial Digital Interface (SDI) connections or over standard networks using SMPTE ST-2110. You can think of AWS CDI as a virtual SDI cable, which lets you build similar workloads across compute instances and services in the AWS Cloud with reliable, high-performance, and interoperable transport of uncompressed video. 

AWS CDI enabled video preview in Flame. 

As part of the 2023.3 release of Autodesk Flame, Autodesk has added support for CDI video monitoring on Flame workstations running on AWS. This allows for sending ultra-low latency, uncompressed video to other software running on AWS at up to 4K 12-bit at 60 fps. With this release, CDI can be selected as a Broadcast Monitor target in the Broadcast Monitor preferences section (1), providing the ability to configure the networking, route the CDI signal, and include transfer function metadata (2). All color spaces are supported (3), as well as all Flame broadcast timings (4). 

What the CDI integration allows us to do is send uncompressed videos to other partner solutions, such as Streambox and Colorfront. Those solutions then package and transport the video to a variety of destinations, allowing high-quality over-the-shoulder playback, reference quality monitoring, and lightweight remote streaming. 

Leveraging CDI in Streambox Spectra VM 

At IBC 2022, AWS demonstrated a technology preview of Flame on AWS, with video monitoring over CDI, connected to a Streambox Spectra VM, which performed encoding on an Amazon Elastic Compute Cloud (Amazon EC2) instance. This instance exported two low-bandwidth encoded streams. One was point-to-point, using a Chroma+ hardware decoder. The other, through Streambox Cloud, allowed users to log into a viewing session in Streambox Player on iOS, tvOS, MacOS, or Windows. 

 “It was exciting to discover AWS CDI this year. We immediately saw a great fit with Streambox Spectra Virtual encoders that were already running Cloud applications on AWS. Within a few weeks we got a prototype running for CDI Encoding and Decoding using the CDI SDK, testing 4K feeds from Oregon to Ireland at 120 ms latency.” – Alex Telitsine | CTO at Streambox Inc. 

The point-to-point stream to the Streambox Chroma+ was used to drive an LG C1 OLED TV. This configuration provided a UHD video preview, with the 10-bit precision required by HDR10, with 3-4 frames of latency. The CDI signal was stable throughout the event, even via the often noisy trade show public internet, from the AWS Europe (London) region to the RAI convention center in Amsterdam. 

After IBC, Streambox and Autodesk collaborated to allow Spectra VM to run on the same EC2 GPU instance as Flame. This collaboration eliminates the need for additional compute instances, improving efficiency and reducing overall cost, without sacrificing performance or quality. Streambox cloud was used to stream the same signal from Flame to an iPad Pro in HDR10 at 1080P resolution. Users were also able to log in using standard mobile devices to view the stream in real-time, demonstrating the capability to review a session anywhere in the world. 

Colorfront adds CDI support to Streaming Server 

As part of the expanding options available for flexible CDI preview, Colorfront announced support for CDI input for its streaming product Colorfront Streaming Server on December 7, 2022. 

Streaming Server converts uncompressed CDI video to professional, reference-quality HEVC. Coupled with the Colorfront Advanced Streaming Gateway and Colorfront’s Streaming Player, approval and QC can be performed on a variety of remote displays, ranging from 4K projectors to mobile devices. 

Colorfront’s web-based invitation system provides simple tools to add session administrators, create sessions, and send invitations. The invitation system automatically configures the SRT Gateway needed to provide multiple secure streams to multiple clients. 

You can follow these steps to configure multi-user streaming sessions, or simply route a stream to a local Flame suite. 

In the Colorfront Web UI, you can select the appropriate Streaming Server (1) and begin inviting users (2) to the Streaming Session. When the user receives the invite (3), they can click the session link or enter the code that appears into their device (such as an Apple TV or iPhone). Once the stream is connected, the Colorfront Web UI allows you to monitor the currently connected clients.

This provides a fast, secure, and simple way to connect to the output of the Flame station. 

The input from the Flame station is automatically detected (1), including the transfer function (3). The Streaming Server can be configured to set the target resolution and bit-depth for the client stream 

“Implementing AWS CDI was straightforward thanks to the detailed SDK and the useful tips and examples it includes.
The collaboration with the development teams from other AWS partners – especially Autodesk Flame – allowed us to quickly validate workflows, resulting in a fully featured CDI implementation in our Streaming Server.” – Bruno Munger | Director of Business Development at Colorfront. 

The integration of AWS CDI in Colorfront’s Streaming Server allows finishing artists working in the cloud to collaborate with colleagues and clients virtually anywhere in the world. This is achieved by providing users with smooth and responsive remote video playback from their Amazon EC2 instance, even over residential and mobile networks. 

Summary 

As companies like Autodesk, Streambox, and Colorfront leverage AWS CDI, a healthy CDI ecosystem is rapidly forming on AWS for content production video preview workflows. Studios can design solutions for low-latency, high-fidelity streams that best fit their unique requirements and budget. 

This article originally appeared on the AWS Media Blog, January 11, 2023

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