What is IPTV and IPTV/OTT?¶
TV has become a huge part of our lives and now it's hard to imagine a home without it. Currently there are a few digital television services: satellite TV, cable TV, over-the-air TV and the recent ones — IPTV and IPTV/OTT. This article focuses on IPTV, how the TV signal is delivered to the viewer and how Flussonic Media Server can help in implementing such technologies.
IPTV and its architecture¶
Internet Protocol television (IPTV) is the delivery of television content over Internet Protocol (IP) networks. This technology appeared in the late 90s to replace the traditional methods of TV signal transmission.
IPTV is a competitor to the conventional television content distribution like over-the-air broadcasting (DVB-T/T2 in digital format), cable TV (DVB-C/C2) and satellite TV (DVB-S/S2) that are relatively simple to set up and affordable, but offer poorer variety of channel selection. Those types of broadcasting are inferior to IPTV in a number of features, which we will discuss later.
The classic example of IPTV service is that offered by an Internet provider. IPTV's great advantage in comparison with DVB-T/T2 (short for Digital Video Broadcasting — Terrestrial) and DVB-S/S2 (short for Digital Video Broadcasting – Satellite) is a wider selection of channels. If you have provider XYZ's dish installed on the roof, you get to watch only XYZ's TV channels. There aren't too many enthusiasts who would install 3 or 4 dishes from different providers, so a telephone company can offer a wider selection of channels in contrast with satellite TV.
It should be noted that traditional IPTV service uses Internet Protocol, a transport protocol to deliver the video content to the viewer through a cable. So that the operator/provider manages the stream delivery to the end-user. That does not correspond to delivery over the open-access network, i.e. Internet.
Traditionally, the term IPTV describes a specific list of technical solutions for receiving television signal and its retransmission to viewers. A classic IPTV architecture looks as follows (see diagram 1.1):
Diagram 1.1. IPTV architecture
Note 1: The IPTV scheme given above is a traditional one, so in every case it may undergo some changes.
Note 2: signal can be transmitted through various digital television broadcast standards: DVB, ATSC or ISDB.
Further in the article we will use the term video content. Let's agree that by this term we mean not only a video stream, but also an audio stream as well as subtitles, closed captions, etc., if any.
In the simplest case, the IPTV diagram includes a satellite dish, a headend and a set of set-top boxes.
Let's define some terms necessary for further understanding of the delivery of video content process:
Headend is a professional term for a satellite receiver that is capable of capturing a lot of TV channels from different sources simultaneously. A headend has three main functions:
- Converting DVB, ATSC or ISDB signal into bytes.
- Descrambling, i.e. decrypting it.
- Sending this stream of bytes via UDP (User Datagram Protocol) multicast to the network.
Multicast is a method of data transmission to a group of recipients simultaneously. Note that multicast takes place only in the context of a private network or a local access network (LAN). Multicasting is similar to broadcasting, but it only transmits data to specific viewers and not to all of them. It is used to efficiently send streaming media and other content to multiple viewers at once by individual copies of the data.
For more information about sending multicast, see Sending multicast.
Set-top box (STB, "a box lying on top of the TV") is a small computer that contains a TV-tuner input and displays output to a TV set. A main device for controlling a set-top-box is a remote control.
Most IPTV operators use a satellite dish as a signal source to capture content due to its lower cost, but it is not the only possible source. In fact, there may be several sources of various kinds. For example, the headend can capture a signal from both satellite dishes and a TV tower at the same time (see diagram 1.1)
For more information about capturing satellite video, see Capturing Satellite Video.
Capturing one TV channel using professional equipment should cost from roughly $100 to $1000 at a time. A dedicated Internet TV channel with a guaranteed quality costs about the same, but monthly. This is the reason why Internet TV is often provided without any quality guarantees. Sometimes a channel is captured via SDI (a cable transmitting raw original video). This is convenient, reliable and extremely expensive.
So, how is the signal transmitted via IPTV? The signal is transported according to a certain set of rules called protocols for devices to process the signal. Satellite transmits the DVB-S/S2 signal to the satellite dish. Then content from satellite dishes (through same DVB-S/S2 protocol) and/or local antennas (through ISDB-T, ATSC or DVB-T/T2 protocols) is captured by the headend and converted to IP so that the router could transfer it to IP network. Stream is further transported to STB from the router, where it is tuned to be displayed on TV screen. HDMI cable is used to deliver the signal to TV.
A question may rise: why is IPTV better than a simple satellite dish (DVB-S/S2) if the operator installs the dish anyway?
Firstly, the operator installs not one plate, but 5 or 6, or even more, capturing all the channels that can only be reached, so that the subscriber gets a larger amount of various channels. Secondly, IPTV provides more different services. Thirdly, a significant part of the residents of apartment buildings in urban areas are not able to install a satellite dish, because of the fact that the signal from the satellite simply does not reach the dish. This can happen due to the following reasons:
- Typical for areas, where the distance between the buildings is extremely small. In this case, the signal's way from the satellite is blocked by the houses and the dish can not receive it.
- The windows of the apartment buildings face north. The satellites are placed in geostationary earth orbit above the equator. So, in the northern hemisphere they are visible only in the south. Hence, the signal simply cannot reach the dish.
Technically, it is possible to install a dish, but it just will not make any sense.
Some STB's can record and save live broadcasts for the viewers to watch later so they can playback and resume at their convenience.
It is important to acknowledge that recording of live TV broadcasts raises problems with the law. Many decades passed before the lawyers of content providers agreed to the use of the videocasette recorder (VCR) by the viewers. Thereby modern set-top boxes often just copy the meaningless and inconvenient functionality of old video recorders: recording a live broadcasting TV channel according to a preliminary schedule. In this case, a viewer has to preconfigure the STB to record at the right time.
First fairly primitive set-top boxes could only switch channels on a preloaded playlist. Modern consoles often come with web browsers like Opera or something based on Webkit (a free engine for displaying web pages), which are modified for video-specific tasks and processing the signal from the remote control. Usage of a web browser makes it easier to change the interface and add new features (for instance, buying content clicking a single button from the remote control). However, web browsers on slow set-top box processors are slower than some specialized applications, so there are still devices without web browsers on the market.
To provide something more amusing and convenient than just a list of 300 channels that you need to scroll through from the first to the last, a new component comes in handy – Middleware.
Middleware is a separate component of the entire system, a software that provides additional services to users via set-top boxes. It should be noted that Middleware is not suited for some IPTV services and, hence, some set-top boxes receive a fixed list of channels.
With the help of Middleware, a viewer can quickly change the list of channels, classify channels by genre, access recorded live broadcasts, movies, enable the display of various information such as currency exchange rates, weather forecasts, etc.
For more information, see Middleware
That is how the first traditional IPTV model looks like. However, due to technological development this architecture has undergone some changes that leads us to the IPTV/OTT.
For more information about IPTV/OTT, see IPTV/OTT.
IPTV solution based on Flussonic Media Server¶
So, we have examined what IPTV is, its way of content delivery to viewers. What part does Flussonic Media Server plays in this system and how can it be used to implement IPTV?
You can use Flussonic Media Server to create headend with its functionality: capturing the signal from the satellite dish and/or TV tower, descramble that signal and send it over IP network. Flussonic can also capture video streams from DVB boards directly. Furthermore, only one Flussonic server is needed to create a small 100-channel service.
Our product allows you to deliver the content the most efficient way possible and without loss of quality for viewer. So that you can focus on the content maker's and veiwer's experiences, while Flussonic will take care of the rest.
If you have any questions about implementing IPTV with Flussonic Media Server or you are willing to try out our product, please fill out the form to receive a free Flussonic Media Server trial key.
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