OTT or Over-the-Top is a technology of delivering video content over the Internet. Online video services like Vimeo, YouTube or Netflix are all using OTT technology to deliver their content to our screens. The technology is called Over-the-Top because content is delivered using HTTP protocol, which belongs to the top level of the OSI model. Linear TV, time-shifted TV, Video on Demand, streaming and other services can be delivered to any device connected to Internet via 3G, 4G, Wi-Fi or broadband connection.
OTT video streaming technology applications:
All applications can be customized to fit the specific needs of business.
OTT derives from IPTV technology and basically resemble the approach seen in IPTV solutions. Server streams TV channels or videos and distributes them over computer networks to client devices. The difference, however, is huge, because Internet TV use specific encoding profiles, is different in the solution architecture and use network protocols adapted to be efficient on infrastructure supporting the Internet.
Where IPTV use local network, which is comparably comfortable to use, OTT have to deal with more aggressive environment. Different networks, unpredictable routes of traffic, unknown types of equipment and all varieties of client devices makes it hard to ensure flawless streaming of videos. However, special technologies were developed to make Internet TV more reliable.
The first and most important thing that helped OTT to become a reliable technology is Adaptive Streaming. Despite the huge efforts, Internet is not that fast as we all want. Having slow Wi-Fi connection or 4G/LTE that could lost signal sometimes and would revert to slower 3G makes it uncertain regarding what bandwidth can be utilized for video streaming. That’s why OTT streams try to use as little bandwidth as possible. But small video size means poor quality, so a trade-off must be found.
Here’s Adaptive Streaming comes in handy. Basically, what it does is checking what bandwidth is available at the moment and providing video stream of best quality that can be played in current conditions. So, when good speed is available a video of maximum quality will be streamed. That is a crispy detailed image with no visible signs of compression. If network speed is reduced, then stream of lower quality is selected. Switching between high resolution and low resolution streams can be done on the fly with HTTP Live Streaming (HLS) or MPEG-DASH standards.
Content Delivery Network
CDN is another important thing that makes OTT happen. OTT is Internet-based, it can be global and offer ability to watch content in any part of the world. Internet TV use unicast connections, so having just a source server and client devices would consume too much traffic which is expensive and would also imply greater delay.
An elegant solution for this problem was found in using special servers that’s part of CDN. The main task that CDN does is reducing distance between streaming server and client device. It also reduce amount of traffic sent from source server to edge CDN and reduce costs spent on bandwidth. It is done by caching most-rated content on a CDN, so that it is immediately available for anyone connected to that CDN. Various techniques like geo-balancing and load-balancing are helping to use CDN servers effectively. CDN can be private, with dedicated servers installed at colocation data centers. Or it can be a service, like CloudFlare, Digital Ocean, Akamai or Amazon Cltop 5 biggoudFront.
Map showing global CDN network of CloudFlare CDN provider.
OTT Solution Diagram
Examples of OTT providers
YouTube, Netflix, Hulu are most notable and probably the biggest OTT providers today.