Veset – Delivering Live Events Efficiently in the Cloud
Lelde Ardava, COO, Veset
We all know that viewers today want the freedom to watch content over the internet, anytime, anywhere, and on any device. It’s also well recognised that the cloud provides broadcasters with much needed flexibility and scalability making it easier to meet these needs. However, the cloud also relies on IP, and IP networks are built on unicast data transmission, where data is sent from a single sender to a single receiver. Consequently, when broadcasters distribute content over the internet via OTT services, a separate transmission must be sent to each and every viewer that requests a stream. Conversely, with traditional broadcast distribution, a single transmission is sent to many viewers simultaneously, making it a highly efficient mode of distribution. The inability to easily and efficiently deliver a single transmission to many viewers simultaneously like in traditional broadcasting remains a challenge for cloud-based broadcasters.
While unicast works perfectly well for on-demand content, it’s problematic when it comes to live events such as sports events, awards ceremonies and music concerts, because sending high volumes of synchronous streams overloads the network, leading to poor quality and disrupted viewing. This is a challenge for broadcasters, and the problem is only going to worsen as viewer appetite for watching live events over streaming services increases. It is this need for a more efficient way to stream live events, maintain quality and prevent network overload that is driving interest in multicast, which similarly to traditional broadcast, allows a single transmission to be delivered to many viewers.
Understanding Unicast Challenges
With traditional broadcast distribution, a signal is transmitted from one source and is picked up by all receivers (in this case, TVs) within range. It doesn’t matter if ten or ten million people are watching, a single transmission is still sent. Conversely, with unicast, each viewer’s device whether that be a smartphone, tablet or smart TV, connects directly to a server to receive the requested content. For a live sports event being shown on an OTT service, the origin server sends individual streams to each viewer.
Every stream travels its own internet path, so a single server can quickly become overwhelmed by high numbers of simultaneous unicast streams which can go into the thousands or even the millions with high profile events. The Super Bowl LIX for example which was streamed by Fox’s Tubi earlier this year, reportedly reached a peak of 15.5 million concurrent streams. To manage this level of demand, prevent servers from becoming overloaded and to maintain performance, service providers use CDN’s (content delivery networks) to distribute the content across multiple servers.
However, the numbers of simultaneous streams can be so high, that even after taking various actions to ensure quality and a seamless viewing experience, broadcasters can still experience problems. Take the Jake Paul versus Mike Tyson boxing match streamed by Netflix last year: the match reportedly attracted a staggering 65 million concurrent streams, however many viewers complained of poor quality, buffering and startup errors. It’s likely that these issues occurred at least in part as a result of there being such high audience numbers.
How Does Multicasting Work?
Similarly to traditional broadcast distribution, multicast also transmits from one source to multiple destinations. This enables one stream to be sent to multiple viewers simultaneously without having to duplicate it for each recipient. The process uses UDP (User Datagram Protocol), a lightweight transport protocol often chosen for live video because it can move data quickly without the delays associated with some other protocols.
Instead of creating a direct connection to every device, the source sends just one stream into the network. Routers and switches then pass that stream along only to parts of the network where someone has asked to receive it, so servers don’t have to work any harder whether there’s one viewer or thousands. Although using multicast for cloud-based broadcast operations may seem like an easy call, it’s not widely used because as mentioned, IP networks are built on unicast data transmission. Most public cloud providers don’t natively support multicasting, so it hasn’t generally been easy for broadcasters to implement. Having said that, broadcasters can now access third-party solutions that enable multicast functionality in the cloud without too much complexity.
Benefits of Multicasting in the Cloud
Unlike sending a separate unicast stream to each viewer, multicast doesn’t overwhelm the network with repeated copies of the same stream. Only the parts of the network with interested viewers receive the stream, so bandwidth is used far more efficiently. For large-scale live broadcasts, that efficiency is the real advantage. The result is lower bandwidth requirements, greater efficiency, and more consistent quality, even during times of peak traffic.
The multicast approach is particularly valuable for tier 1 and 2 broadcasters and those operating multi-channel operations because it provides an efficient way to distribute content to high numbers of viewers simultaneously without creating too much complexity. Additionally, multicasting is also highly beneficial for broadcasters that use alt-casting (alternate broadcasting), a strategy that is becoming increasingly popular as broadcasters seek to appeal to a broader audience. Popular in sports broadcasting, alt-casting lets broadcasters offer alternative coverage alongside the main event feed, such as alternative commentary aimed at a specific demographic or regional variations, all without overburdening their network. It can also be used to create additional channels for specific platforms and in different formats such as FAST channels.
Future of Live Streaming
The industry is still in the process of bridging the gap between the efficiency of traditional broadcast and the flexibility that cloud infrastructure and IP delivery provides. Multicast offers cloud-based broadcasters a way to efficiently stream live events to the masses without overloading the network or losing precious quality. Multicast may well become part of a broader toolkit that blends efficiency with enhanced viewing experiences, whether that means custom camera angles or supplementary commentary delivered at scale, ensuring that broadcasters can always deliver high-quality live streamed events to viewers, no matter how many are watching.
