Prior to the appearance of OTT, online video delivery was only limited to PCs and some top-end mobile phones. Now the televisions are connected, entering the OTT space.
By Carlos Pantsios Markhauser *
OTT is the latest technology that makes it possible to distribute "Over The Top" (OTT) video content of all conventional distribution technologies. It does this by transmitting data streams that use HTTP (Hyper Text Transport Protocol), a protocol used for decades to transport web pages over the Internet.
HTTP is based on Transport Control Protocol (TCP), a secure connection transport protocol that has more practical elements than the popular User Datagram Protocol (UDP). The TCP connection allows anyone with sufficient web hosting capacity to broadcast audio and video content to a global audience on the open Internet.
In its simplest form, OTT is fundamentally an alternative technology that allows replication of the repertoire of traditional entertainment content but in a fully digital context.
OTT consists of delivering content through fixed and mobile internet connections, replacing the TV broadcast spectrum or dedicated cable, fiber, or satellite networks.
Although OTT technology reflects traditional video content, its digital domain allows for many of its own characteristics and elements that are not possible in air, cable or satellite distributions.
Some OTT Technical Details
HTTP is the protocol that was used as a transport solution for video-on-demand media (VOD) contained in web pages, especially in Adobe Flash-based sites, such as You Tube, Hulu and Dailymotion. However, it is very important to note that these solutions do not stream in real time, basing their operation on the so-called progressive downloading of media content files.
In this case, the browser downloads the file from the HTTP web server and when you have enough information, initial playback of the content while continuing to download the rest of the file. The major disadvantage of this form of operation is the extended time required to fill the initial buffer. Another problem associated with HTTP is the quality of streaming, which depends on the IP connection. Content streaming is subject to stagnation if fluctuations in available bandwidth occur, leading to image freezing. This makes it almost impossible to broadcast live content over the Internet.
The principle of operation of OTT is to work with video streams or files based on TS streams (Transport Stream). While an OTT container uses the MPEG transport stream (MPEG-¬-TS) for video, the AAC is used for audio, both of which are widely used in the broadcast industry for many years.
Another strength of OTT is its ability to implement intelligent adaptive bit rate. Here, it is the end user device that decides the quality of the streaming, according to the available bandwidth, and not the video server, as it was traditionally done. This technological solution allows to achieve uninterrupted video streams, thus achieving a very positive user experience (QoE) through an unmanaged network (eg, Internet).
Until recently, live broadcasting was therefore restricted to operator-managed IPTV networks employing the lightweight UDP multicast protocol. The entry of OTT technology into the world market, however, has brought a new approach and it is now possible to achieve quality levels of streaming over HTTP that allows live content in broadcasting over the Internet.
In OTT, an index file is generated indicating different profiles (streaming qualities) available for a channel / content file. On the other hand, the receiving device (PC, mobile, STB) searches for the most appropriate bit rate, based on the time required to receive a file block. Each file block lasts about 10 s, so that the receiving device can automatically adapt the streaming with flexibility in that time.
The OTT streaming has brought with it a new technological approach that now allows streaming quality levels over HTTP never before achieved and that enable live content to be sent via broadcast over the Internet.
Why the nervousness in telecom companies with the appearance of OTT?
Until very recently, high-quality video delivery was monopolized by companies working with managed networks, such as telecom operators (telcos) and Internet Service Providers (ISPs). The revolution came in the year 2002 when the company FastWeb (Italy) proposed the offer of large-scale video over IP.
The emergence of OTT technology meant that a managed network is no longer essential for quality video (QoS) delivery. This implies an open threat to telcos who fear a "disintermediation" (ie, elimination of intermediation in the video delivery chain --- referring here to networks operated by administrators) being relegated to simple broadband vendors. band on the Internet, a position they have been radically opposed for many years.
There is, however, a perfect OTT opportunity for telcos. Many of them are currently building new offerings that allow them to reach new users, and even extend video offerings to subscribers of other ISPs.
On the other hand, OTT technology can be seen as the facilitator of a multiscreen type convergence, delivering video content to different user devices already, that HTTP is used in both PCs and STBs, connected TVs and mobile devices.
OTT technology allows new participants to emerge by creating a direct connection between content providers (TV channels, content aggregators, satellite and cable broadcasters) and end users. OTT makes it possible for content providers to directly promote their video services to users.
Content providers have been at a disadvantage in the battle of telco vs. broadcasters over the administration of end users while telcos have gained a significant advantage through technology IPTV and VOD offers, including triple play packages. With the arrival of OTT, content providers will be able to re-gain a position by marketing and delivering their content directly to connected TVs and mobile devices.
Other Important Advantages of OTT Technology
Before the emergence of OTT technology, online video delivery was only limited to PCs and some top-end mobile phones. Now it is possible to observe the emergence of so-called connected TVs, entering the OTT space. Connected television allows consumer electronics manufacturers to bring new value to TV delivery as this allows direct contact between users and content providers.
Mutual agreements were created between the manufacturers of TV receivers and content providers to improve their mutual offerings. Another new market for content by OTT are tablets. The tablet war, which began with the Apple iPad, will continue in the years ahead with fierce competition between hardware and software manufacturers.
Another example of emergence of new entrants ready to take advantage of OTT's opportunities are retailers that currently have a stake in the fixed and mobile telco markets and Mobile Virtual Network Operators (MVNOs). Both have a strong user base with a local presence, and their core business is delivering devices to consumers such as TV receivers, tablets and other video equipment to connect. OTT is able to enable them to improve the management of their relationships with consumers through a complementary video offering, linked to the electronic devices they distribute themselves.
Main actors in OTT technology
OTT technology continues to be a technological battlefield where no clear winner has emerged. The four contenders of advanced technology OTT, such as: Apple HLS, Google WebM, Microsoft Smooth Streaming and Adobe HTTP Dynamic Streaming, all come from the Internet market sector, totally devoid of links to the broadcast and telecommunications industries.
In 2010, 3GPP and OIPF published their own specifications for adaptive streaming protocols; Adaptive HTTP Streaming (AHS, part of 3GPP R9) and HTTP Adaptive Streaming (HAS), however adoption of these protocols still did not occur. The MPEG-¬-LA and ISO organizations have taken the lead by creating a simple cross-industry standard in order to unify the adaptive streaming over HTTP protocols: MPEG-¬-DASH (Dynamic Adaptive Streaming over HTTP). The first written on DASH specifications was published in February of 2011.
Due to popular demand, MPEG-¬-DASH introduced an optional function: the initialization segment. The initialization segment is an MPEG --- TS format containing a simple program, its program specific information (PAT, PMT) and some optional codec and DRM information. The advantage of this is that duplication of this information is not required in the subsequent media segments. This has the enormous advantage of faster channel switching, which contributes to a substantial improvement in the quality of experience similar to the change of traditional analog TV channels.
In this contest of different technologies based on OTT, it is very difficult at the moment to know which of them will dominate the future of OTT (no matter which one is really the best!). This is because these technologies are promoted by very heavy players in the telecommunications industry and therefore each is creating a great impact on the market.
* Carlos Pantsios Markhauser is an engineer in Telecommunications and Magister in Communications of the Simon Bolivar University, Specialization in Telecommunications in satellite and networks The George Washington University-School of Engineering & Applied Science, Specialization in Digital Telecommunications University of Colorado Boulder. He currently serves as Technical Director at the consulting firm Mediax Gente de Medios. You can contact him through email@example.com