AWS for M&E Blog
Enabling real-time audio using multicast on AWS
This blog was coauthored by Patrick McCoy, Chief Product Officer of swXtch and John Schur, President at Telos Alliance TV Solutions Group.
Reliable, low-latency solutions are critical in the media and entertainment industry. This is especially true for intercom systems serving live production teams working across multiple locations. Producers, directors, camera operators, audio engineers, roving reporters, and others must collaborate in real time. Media production teams are looking for audio systems with flexibility and scalability.
We will explore how Telos Alliance, swXtch.io, and Amazon Web Services (AWS) joined forces to enable scalable near real-time audio workflows in the cloud. Now, production teams can enhance the scalability and availability of their mission-critical workloads while maintaining the familiar operations and functions of their traditional environments.
Audio workflows and the role of multicast
Live production (including intercom), contribution, and broadcast distribution audio workflows often comprise hundreds and thousands of live audio streams connected to hundreds of devices. SMPTE ST 2110 audio applications and many other audio workflows depend on multicast as an efficient way to distribute audio streams to multiple recipients simultaneously, reducing network load and bandwidth usage. Without multicast in the cloud, live audio workflows require significant operational changes, which can impact their scalability and flexibility.
As real-time audio workflows require low and deterministic latency of less than a second, a multicast network overlay solution must enable these parameters.
Multicast with standard Internet Group Management Protocol (IGMP) joins and leaves is also key to large-scale audio productions. Endpoints can rapidly subscribe to multicast streams and change subscriptions within milliseconds, rather than requiring human intervention to manually configure individual unicast links.
The challenge with scalability
Broadcasters and production teams have long relied on multicast switching capabilities in on-premises workflows. Having great scalability (managing hundreds of connected panels and thousands of audio streams simultaneously) requires network optimization in the cloud. While unicast may be suitable for many customer workloads, real-time audio workflows are more efficient with multicast. As media creators begin to leverage the cloud, they expect seamless integration between their on-premises multicast networks and those of the cloud.
On AES67 and ST 2110-30 production in the cloud
SMPTE ST 2110 has become a widely adopted standard for the distribution of video, audio, and metadata in on-premises facilities. It comes with many advantages over more hardwired approaches, including scalability, low latency and high-quality media flows. ST 2110-30 is the uncompressed audio standard that incorporates AES67 Audio over IP to transport audio in RTP packets over multicast connections.
When using SMPTE ST 2110 for on-premises deployments, Telos Alliance Infinity VIP synchronizes to media through Precision Time Protocol (PTP) On AWS, Telos Alliance Infinity VIP makes use of Amazon Time Sync Services to synchronize the host clock with global time. The accuracy of Amazon Time Sync Services meets the requirements for audio synchronization in the cloud and in hybrid cloud and on-premises systems.
Enabling dynamic multicast for hybrid environments
swXtch.io’s cloudSwXtch intelligent media network provides the multicast connectivity and elasticity required for real-time distribution across multiple locations to support global live productions. It enables seamless connectivity into and through the cloud to replicate the local area network functionality while allowing access to datacenter resources. Telos Alliance virtualized their intercom and audio products for use in hybrid (on-premises and cloud) systems.
Solution architecture
Figure 1: High-level architecture.
The following is a description of the different areas within the high-level architecture:
- Intercom clients are distributed globally in venues, outside broadcasting (OB) trucks, and studios. The intercom users could be producers, directors, camera operators, roving reports, talents and more. Hundreds of connected intercom panels could be required for major sporting events. Telos Alliance belt packs connect to the AWS Cloud through a Telos Alliance Infinity VIP and cloudSwXtch, enabling over 512 live conversations to take place across the connected venues and cloud. To transmit and receive audio over multicast in a hybrid environment (on-premises and cloud), cloudSwXtch Bridge application is used to enable multicast joins and leaves between connected nodes. Bridge is installed on an appliance server on premises.
- Signals are transmitted and received between the on-premises locations and the cloud using AWS Direct Connect or over the internet. This is determined by the format and bandwidth requirements. For example, for ST 2110-30, customers tend to have AWS Direct Connect available to verify dedicated bandwidth and deterministic transport of content.
- Once in the cloud, audio feeds are switched to the nodes using standards-based IGMP v2 join requests using cloudSwXtch. This is the router appliance that runs on Amazon Elastic Compute Cloud (Amazon EC2) instances enabling multicast network overlay. Beyond routing, the cloudSwXtch manages the deployment and communication with the xNICs that are integrated into the applications running on EC2 instances.
- xNICs are software agents that facilitate multicast transport between EC2 instances on the swXtch network. Applications running on EC2 instances, such as the Telos Alliance VIPs, are able to send and receive multicast streams through the xNIC, regardless of where the senders or receivers are located. The latency from the venues to the Telos Alliance VIP instance in AWS is around 150 milliseconds (ms). This is measured from the time a person hits the “talk” button on their intercom endpoint (phone, tablet or computer) until their audio stream has joined the Telos Alliance VIP system (virtual matrix) in the cloud. Additionally, as stream reliability is critical, cloudSwXtch implements hitless packet merge (SMPTE 2022-7) with the Telos Alliance VIP intercom nodes. This ensures audio stream resiliency with no impact to latency.
Conclusion
We showed how using the multicast implementation of swXtch.io’s cloudSwXtch platform and Telos Alliance containerized audio software products, customers can extend their workflows to the cloud using SMPTE ST 2110 to achieve highly scalable, flexible, and low latency solution. Users of this solution can choose from several models for resilient operation, spinning up and down workflows as needed, and dynamically integrate functions to meet changing requirements.
Are you ready to extend your audio workflows through the cloud? Contact us or reach out to Telos Alliance, and swXtch.io to learn more.