Build A Foundation For World-Class OTT Delivery

Over-the-top (OTT) video is increasingly challenging the traditional broadcast model with added convenience in terms of both user experience and reach. Thanks to a growth rate ten times that of traditional TV, OTT already accounts for 15 percent of total industry revenues and is projected to approach one-third of the market by 20221.

Even so, effectively delivering content over the internet requires care and consideration. Ill-prepared content providersoften struggle with issues such as limited bandwidth, latency, managing two-way communication, and compression standards among others. A strong technological backbone is necessary to support the many functions needed to deliver great video experiences over the internet.

First-Mile Network Management

One of the first and most critical steps in the streaming delivery journey is IP transport. The primary goals need to be latency minimization and avoiding quality degradation.

Advancements in HTTP/2, which became a published standard in 2015, allow providers to skip a step with the transcoders by delivering content to the origin servers following transmission control protocol (TCP)-based streaming techniques. But TCP does have some trade-offs, sacrificing low latency for high reliability, especially the further the signal has to travel.

Depending on priorities, providers can also consider user datagram protocol (UDP) -- a connectionless protocol that requires no communication between sender and client. UDP shines by delivering low-latency and better bandwidth utilization than TCP, but sometimes drops packets resulting in lower reliability.

First-mile distribution requires high-quality control to guarantee satisfactory performance on the way to the origin before it is distributed to all viewers. Multipath redundancy ensures content will be delivered in this critical stage without any interruption to the ingestion points. In the case of global live-event streaming, providers should have two fully diverse paths at a minimum, and in practice three or more for delivering critical content. 

Delivering content to smartphone and other OTT viewers requires no less focus on quality than does traditional TV.

Delivering content to smartphone and other OTT viewers requires no less focus on quality than does traditional TV.

Linear channels also require consistent, 24x7 performance, heightening the risk of interruption due to their “always-on” nature. A two-path redundancy model should be considered the baseline. Depending on the channel or content, operators may opt to consider three-path redundancy models as used for high-profile, live event delivery.

Whatever the chosen redundancy, content providers must maintain continuous performance monitoring and analysis through first-mile distribution points—and they must ensure that together with their internet service providers (ISPs), they can address anything that might cause a poor user experience. This constant monitoring allows identification of issues with the primary paths and active alternative routes before they disrupt the user experience.

Origin Infrastructure & the CDN

The primary goal of moving content from the post-production environment or a linear channel playout to the origin server is to ensure that the content can propagate to the next point in the delivery chain while maintaining high quality. Linear streams need to be accessible from any display at the low-latency and high quality levels of traditional TV. Playback of on-demand OTT content needs to start as quickly as traditional mediums.

Ingesting packaged content onto origin servers that can be accessed by content delivery networks (CDNs) is critical to the video stream’s success. Live or 24x7 linear video services reaching large audiences need an encoder that pushes content to an origin equipped to handle massive call volumes for content-over-CDN infrastructures. The origin must also be able to support dynamic identification of optimal entry points based on factors like network conditions and audience locations; and also supporting optimal modes of transport to minimize latency with no loss in quality. For on-demand scenarios, content providers need highly scalable infrastructures to support their origin services. These should optimize storage for high-performance video by working in tandem with distributor workflows.

Providers using their own origin infrastructures must have sufficient capacity to handle all calls from all CDNs, as well as separate backup facilities in the event of an origin failure at the primary origin facilities.

Next-Generation Compression Standards

Content providers must have a strong understanding of the trends in the compression codec landscape in order to make the right choice for their business. Uncertainty in the industry points to the need to pay closer attention when choosing codecs.

The advent of 4K ultra high-definition (UHD) has encouraged content providers to look beyond H.264/AVC, the longtime dominant standard codec in video streaming. Many are now looking at alternative codecs like H.265/HEVC, which can consistently deliver a peak 50-percent improvement in compression efficiency over AVC.

Built-in support for 4K UHD from the latest smartphones and TVs demonstrates industry confidence in the quality of 4K UHD streams. HEVC has gained traction in advance of wide-scale UHD availability, as well as on the encoder side, as content providers and distributors replace or expand encoding assets.

HEVC can provide up to a 50-percent improvement in compression efficiency over AVC.

HEVC can provide up to a 50-percent improvement in compression efficiency over AVC.

But we may not reach the industry consensus with HEVC that we had for AVC for some time given the emergence of other next-generation codecs. Royalty costs remain an obstacle for HEVC, while other high-performing options like Google’s royalty-free VP9 and the Alliance for Open Media’s AV1 may prove to be attractive options.

Because not all codecs support all devices, it is advisable to consider multiple codecs when the economics make sense. The rule of thumb is to consider implementing new codecs at the point where the savings on delivery costs reach the incremental cost of storage and encoding. The economics of any use case should always be the deciding factor in choosing the right mixture of codecs to support optimized delivery to all target devices.

External Streaming Networks

The ability to consistently achieve and exceed minimum quality standards for streaming depends on a strong CDN to support seamless delivery from the origin to the end user. One of the most important characteristics of that CDN is the location of its edge facilities. These must be located near targeted users. A highly distributed architecture can minimize the impediments to delivery over last-mile access networks.

CDN operators who rely on Border Gateway Protocol (BGP) routing, which is not a performance-based protocol, to find the lowest-latency routes may struggle for quick responses in the case of outages or severe congestion. A well-designed, distributed CDN architecture creates an internal transport environment that avoids the pitfalls of relying on the open internet.

When evaluating a CDN, content providers should consider their needs for their audience. If the providers have a global audience, they should look for a highly distributed platform with software that can dynamically map end users to servers to accommodate the highest possible performance. For providers looking to achieve optimal connectivity between all origin entry points and edge facilities should look for advanced capabilities, such as the ability to route around BGP inefficiencies, multiplex connections, and high-efficiency transport platform utilization.

Dramatic internet innovations have brought sweeping changes to the businesses of content providers. The landscape is changing quickly while technology is at the same time making providers’ lives easier while also raising the expectations of consumers. The right OTT delivery foundation ensures that every step of the process works cohesively to continue delivering the first-rate experience viewers have come to expect.

1  Digital TV Research, “OTT and Pay TV Forecasts”

Author: Melis Unsal, Manager, Global Product Marketing, Akamai

Author: Melis Unsal, Manager, Global Product Marketing, Akamai

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