An OTT video delivery system uses an array of video servers to stream content in multiple formats and standards ex:HLS, HSS, HDS, MPEG-DASH.
According to a 2015 study from Digital TV Research, global OTT TV and video revenues will reach $51.1 billion in 2020.
While pure OTT providers such as Netflix and Amazon certainly command a large portion of that revenue pool, cable and satellite operators are starting to explore launching their own OTT offerings in order to appeal to cord-cutters and stay competitive. Accenture recently reported that Sky’s OTT service in the United Kingdom — called Now TV — has helped increase its subscriber base by targeting pay light customers, and decrease customer churn.
For now, many cable operators are focusing on using OTT delivery as a complement to their main TV service offering, satisfying the consumer demand for high-quality video on any device, including smartphones, PCs, and tablets. One of the main issues that operators face with OTT video distribution is how to address the surge in viewer consumption that inevitably takes place during popular live events such as breaking news or sports. Whenever this happens, the edge network becomes congested, resulting in poor quality of service (QoS) for viewers.
As operators look to launch 4K services, delivering OTT live TV will become even more challenging, since 4K content consumes more bandwidth. Operators will need a more scalable content delivery network (CDN) solution.
This article looks at the benefits that OTT distribution provides as well as key differences between OTT and traditional video delivery, explaining how recent advancements in adaptive bit rate (ABR) technologies can be utilized to deliver OTT multiscreen video in the most cost-effective manner possible.
Key Differences Between OTT and IPTV Distribution
Operators are moving from IPTV to OTT in order to take advantage of a wide range of benefits that OTT offers, such as the ability to deliver video content from a unified platform, streamlined operations thanks to standardized equipment, simplification of deployments, less maintenance, and the capability to reach STBs that can receive ABR streams.
While both OTT and IPTV rely on streaming video servers, their distribution networks are quite different.
Yet, before cable operators launch an OTT service, they should be aware that there are a few stark differences between OTT and traditional distribution methods like IPTV. For starters, OTT video content is generally made available to subscribers via Web portals or apps on second-screen devices like computers, tablets, smartphones as well as connected TVs. So while there is no need for a set-top box when it comes to viewing OTT content, operators will need to design and create an app in order to make that content available to subscribers.
There are also different bandwidth considerations to take into account. Overall, OTT is less reliable than IPTV. Because IPTV services are delivered directly by the cable operator, bandwidth is guaranteed, whereas with OTT video content, it is delivered together with all the HTTP traffic that travels on the Internet, without specific privileges. Moreover, in order to be compliant with smartphones, tablets, and connected TVs, standard OTT delivery requires that point-to-point unicast streaming is used, even for live content. This implies that each user consumes resources that are not mutualized, compared with IPTV, which benefits from multicast technology that allows a single stream to address all the users watching the same live content. During live news and other major events like sports, this can be especially problematic since the number of viewers can be quite large. There are a few steps that operators and ISPs can take to address this issue.
Three Technologies Designed to Alleviate OTT Delivery Issues
Adaptive bit rate formats, such as Apple HLS, Microsoft Smooth Streaming, and MPEG-DASH are designed to improve the user quality of experience. When an ISP’s network has been saturated to a point where it cannot transport a high-quality signal, or if the bandwidth available in the local network of the user has all been consumed, the receiver requests a lower bit rate from the server. By reducing the bit rate, ABR technology ensures that the signal can be delivered, albeit with a slightly reduced video quality. When the network conditions improve, the bit rate and the quality increase again.
Adaptive bitrate streaming is based on HTTP and requires the use of an encoder that can generate a single source of video at multiple bit rates. The receiver detects a user's bandwidth and CPU capacity in real time and adjusts the quality of the video stream accordingly.
Another solution that can be used by operators to improve OTT video delivery is the deployment of local caches dedicated to unmanaged video content in their networks. In this case, we are talking about content that is delivered directly by content providers through a “CDN as a service,” like Akamai, Level 3, or Limelight. Through agreements with content providers, operators can access the right to cache their content locally in their own network and install homologated HTTPS certificates when necessary, which is an advantage over transparent caching technologies that do not allow the caching of content protected with HTTPS.
Multicast is another technology that is making an impact on live ABR delivery. For many years, the majority of OTT content has been delivered via unicast. Unicast is a perfectly efficient solution for video-on-demand content, but there are drawbacks of using this technology for live content delivery. Unicast requires a separate router request in the network each time that a viewer tunes into live content. Let’s say there are millions of simultaneous viewers watching a live event; this can put a huge strain on the operator network. With multicast, television operators can stream live content only once in the network, regardless of the number of viewers watching. For example, a cable operator could stream one of the world’s largest sports games to millions of viewers in 4K, using only a few Mbps from the operator network.
Through the content delivery technologies described in this article, cable operators and ISPs can work together to dramatically improve the way that they are delivering OTT content, optimizing bandwidth usage, lowering costs, and providing viewers with a better television experience, including 4K. As the OTT and 4K markets heat up in 2016 and beyond, it will be critical for cable operators to partner with a CDN technology provider that supports these advanced technologies if they want to guarantee a high QoS for viewers on every screen at a fraction of the cost of traditional content delivery methods.
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