IPTV and OTT basics
IPTV Deployment is a Challenging Task
First commercial IPTV deployments started already in the beginning of the Millennium. Since then IPTV and OTT industry became mature and in Europe it is hard to find an operator without the IPTV service. However, in Sub Saharan Africa, some parts of Middle East and Latin America, there are still many service providers in phase of launching or even still considering to start the IPTV service.
These service providers face quite some challenges. It might seem trivial, but with so many different vendors and systems and no standards, even basic naming of the TV services, components and their functions become tricky and I have to admit it, sometimes it’s fun too. From our experiences working with operators in Africa, Middle East and Latin America, we found that basic description of the TV services and IPTV equipment is very useful and a good thing to start with.
Blog is prepared for newcomers in the IPTV and OTT industry, to make your life easier and to help you on the path of designing and launching a fast growing IPTV / OTT service. In case, you are already familiar with the IPTV basics, your next step might be an article How to start an IPTV / OTT Turnkey Solution? or find out if your network is ready for the IPTV and OTT service in the article Network Requirements for IPTV and OTT Service.
What is the difference between IPTV and OTT?
So first, let’s take a look what is the difference between IPTV and OTT or Internet TV. Both IPTV and OTT, are about delivering video content and interactive TV services using the IP network.
Main difference is that IPTV delivers video content in the managed network, fully controlled by the operator, while OTT as the name applies (over the top) is designed for video delivery over public Internet. In IPTV, multicast is used as a transport of Linear TV content, saving bandwidth in the operator network. OTT is always unicast traffic, for Linear TV and on demand content, using adaptive streaming technologies, such as HLS from Apple. Adaptive streaming allows client devices to adapt streaming profile/bandwidth to current network conditions, providing good user experience even in non optimal network conditions.
Sometimes, term OTT is used also in cases where TV service is offered on the mobile and/or PC devices, in addition to the STB connected in the operator’s managed network. More often, term multiscreen is used, meaning that TV service is offered on other devices such as mobile phones, tablets and PCs. OTT term is also used for any combination of devices where content is delivered over the Internet, e.g. STB outside operator’s private network, mobile or PC devices over public network, or any combination of it.
Most Popular TV Services
In the IPTV or OTT, there is a list of most commonly used TV services. However, you can often find different naming for the same service. One of the first things we do when starting IPTV project is to get aligned with the customer on the naming of the used TV services. To avoid funny situations, here is a list with the brief explanation for each service. For more detailed overview, you can download the UniqCast Turnkey IPTV / OTT solution presentation.
Sometimes it is referred to also as a Live TV, means watching Linear TV channels (TV or radio channels) in real time. User is able to browse through all available channels and zapp to the selected one.
Fast Channel Change
It is an improvement of the Linear TV, speeding up zapping of TV channels, significantly improving TV experience. Usual zapping time in IPTV is between 1,5 to 2 seconds, while with Fast Channel Change service, zapping can be improved from 1 up to 0,5 second.
Usually it comes together with the Fast Channel Change and improves quality of the delivered Linear TV content. It corrects packet loss errors on the STB client, providing good video quality even in non optimal network conditions. This is especially important on the DSL lines.
Provides mosaic view of selected TV channels on one screen, allowing viewers to quickly find interesting program and switch to it. User is able to navigate through TV channels in the mosaic, getting video, audio and EPG information for the selected channel.
Picture in Picture
While watching a Linear TV channel, viewers are able to bring up another, small size window, showing what's playing on other Linear TV channels. In this way, you are able to check program on other channels without leaving the currently watched channel.
Electronic Program Guide provides to the viewers detailed information about the TV program. It can include pictures, show description, title and casting information, but information depends on the selected EPG provider. Viewers can browse EPG for a selected Linear TV channel in the future or past for a configured period of time. There are several different views of EPG, matrix or horizontal EPG, being most widely used, vertical EPG with a newspaper like view and info bar, providing current show information while zapping.
Users are able to initiate search for the defined keywords and find an interesting content, whether live or on demand. Usually, search is possible on different parameters, such as show title, description, casting, etc. allowing viewers to quickly find the content they have been looking for and start watching it within few clicks.
Catch Up TV
It is one of the most popular and widely used IPTV services, allowing viewers to watch TV shows on a selected Linear TV channel in the past, within the configured period of time. Recorded content is stored in the network and streamed to the users on request. Majority of the watched Catch Up TV content is within the current and last day, after that content consumption rapidly decreases. Time period for the Catch Up TV service directly influences required storage capacity on the streaming servers. Catch Up TV is sometimes called Timeshift, even though term timeshift is more often used for storing last few hours of the currently watched TV channel on the PVR capable STB device.
Start Over TV
Usually, it is combined together with the Catch Up TV service, allowing viewers to start playout of the show currently being watched from the beginning. It is useful in situation when user misses start of the show and is able to watch from start with single press on the remote control.
Pause and Resume
Can be a part of the Catch Up TV service or sometimes even a separated service, allowing users to pause currently watched Linear TV channel and resume it at some time later. After resume, user watches content in the past, in the same way as for the Catch Up TV.
Sometimes, it is also called nPVR. Viewers are able to record show based on the EPG information, on any Linear TV channel with activated nPVR service. Recorded content is stored in the network. User is able to watch recorded show at any time later, but within the recording expiration time.
Video on demand service allows browsing through available VOD content catalogue, checking information about the selected movie, such as description, casting, price and trailer and watching purchased VOD content. VOD service can be provided in two variants, as a pay per view VOD, where subscriber pays for each movie separately for limited period of time (e.g. 24 hours), or subscription VOD, where movies are offered inside monthly subscription fee. Subscription VOD has usually much higher usage comparing to pay per view, although it depends on the geographical region and quality of the content as well.
Required IPTV and OTT Subsystems
For above listed TV services to function, several different components should be included in the solution. In the next section a brief explanation of each component is provided. For more detailed overview on the complete solution, please download the UniqCast Turnkey IPTV / OTT solution presentation.
It is the first component in the chain for acquisition of video channels. It is used to receive satellite or terrestrial TV signals and pass it forward to receivers and encoders. Video signals received over air can be in standard or high definition quality (SD or HD), it can be free to air or scrambled.
Used to feed several receivers from a single antenna/LNB. It is used to split source signals of different polarity to two receivers. Signals can also be splitted to provide redundancy on the receiver and antenna level.
Used to connect all the components of the solution with ethernet interfaces and provide IP connectivity between them. Depending on the network design, it can be L2 or L3 switches. To organize multicast video delivery, switches should support IGMP snooping and provide enough processing power. Use of L3 switches is recommended, to route the traffic between different VLAns and in this way simplify potential troubleshooting in the production phase.
It filters incoming and outgoing network traffic and protects IPTV/OTT systems from intrusions and DoS attacks. This specially becomes important in case of OTT service and connections to external systems. Usually it also provide remote access to equipment for the management purposes. In some cases, firewall as a dedicated appliance can be replaced with access list on the L3 switch.
Core or provider edge (PE) network router in the operator network presents main connectivity point between IPTV/OTT system and operator network. It requires PIM functionality for the routing of multicast streams and IGMP Querier functionality to establish permanent multicast presence in the core network.
It is also called integrated receiver decoder or shortly IRD. Main purpose of the device is reception of satellite signals from antenna, decoding received signals and forwards it to video encoders. Today, most widely used interface between receiver and encoder is IP, but there are also ASI and SDI legacy interfaces, that are still available on the market. For encrypted satellite signal, receiver needs to have proper Smart Card or decryption module to decrypt the signal.
In theory, encoder is a device that encodes video signal in a format suitable for delivery in the IP network, while transcoder first decodes video signal and encodes it again in different format. However, in practise both terms are often confused and used for same devices. It include functions such as signal reception, routing, encoding, content protection, formatting, multiplexing and modulation. It transforms video signals got from receivers into multiple formats and resolutions, encode to H.264, protect and package them for each targeted network and device. Additional feature of the encoder can be a smaller resolution stream, used for picture in picture feature. For OTT, encoders can also include so called chunker or segmenter functionality, segmenting input streams with multiple profiles into chunks. If required, HLS chunks are encrypted by OTT encoders before being uploaded to streaming server.
Content and Subscriber Management
It is often referred to as a Middleware. It presents the central entity in the IPTV/OTT solution, providing subscriber, content and device management and integrates with other systems such as DRM, VOD, billing, provisioning, EPG and VOD providers. In most cases, it is based on the server - client architecture, where server part provides all business logic and integrations with other systems while different client applications connect to server and provide user interface and other TV services to the viewers on STB, mobile and PC devices.
It protects video content delivered to the end user devices in the IP network. For IPTV, it takes multicast streams from the encoders, encrypt them in real time and send out as multicast to end user devices, while VOD content is encrypted offline. DRM also interacts with the Content and Subscriber Management System, to deliver proper key to the end user device, in order to decrypt the content for a specific subscriber. For OTT delivery, content is encrypted already on the encoders, but DRM still needs to control delivery of the proper keys to subscribers.
It stores video on demand content, records Linear TV multicast streams as instructed by the Content and Subscriber Management System and streams on demand and recorded content to the client devices. VOD server is usually used for delivery in the managed network, while for OTT service, term OTT Streaming server is most widely used. Today, as operators offer TV service not only on the STBs, but also to the mobile and PC devices, it makes sense to use only OTT Streaming server and use HLS streaming for mobile devices and STBs over Internet and in managed network as well.
OTT Streaming server
Similarly as VOD server, it stores video on demand content, records Linear TV HLS streams as instructed by the Content and Subscriber Management System and streams on demand and recorded content to the client devices. Main difference is that is streams VoD and recorded content to the end users in a format of HLS.
It is still most widely used end user device controlled with the remote controller. It decodes received video signal in a format proper for presentation on the TV. STB provides different interfaces for connecting TV such as HDMI, SCART or composite. If required, it also decrypts video signal using dedicated DRM client that needs to be integrated on the STB.
STB Upgrade/Boot server
It is used for remote upgrades of the STB devices. There are different upgrade mechanisms used. In the managed network, STB SW can be delivered to the devices using multicast, FTP or HTTP methods. For OTT STB devices, use of HTTP delivery is usually the only option. For Android STB vendors, upgrade server can be in the cloud and maintained by the STB vendor.
It provides centralized collection of logs from all STB devices, allowing operator to proactively monitor health of its TV service. Either in case of a specific complaint from the end user or proactively finding a suspicious pattern across many STB devices, STB monitoring server enables efficient troubleshooting and quick resolution times.
Auto Provisioning System
It enables operator to automatically provision STB devices in the system without manually inserting password from the end user or field engineer. It works in combination with the DHCP server and operator’s provisioning system.
Video Stream Monitoring
Provides monitoring of multicast and HLS streams in the centre and edge locations. It requires special monitoring probes to be installed on each location, measuring parameters relevant to Quality of Experience and providing alerts and visual presentation of results.
It performs backup of all critical information for all server based IPTV components. It periodically performs full and incremental backups, allowing operator to quickly restore full systems back in operation in case of disaster recovery.
Central Monitoring System
Provides overview on current status and pending alerts of all IPTV components. It monitors the solution components using SNMP, syslog or other monitoring protocols.
It enables operator to automatically add subscribers, devices and control activation and provisioning of TV services directly from it’s selling points. Integration is done using API on the Subscriber and Content Management System in order to provision, activate or deactivate subscribers, STB devices or services.
It collects charging information from different systems and generate bills/invoices for each subscriber. Billing can be of postpaid, sending invoices after service is consumed or prepaid, where user needs to pay amount of money in front and is charged in real time for consummation of each TV service. Integration is done using API on the Subscriber and Content Management System in order to get charging information about TV service for TV subscribers.
Every STB device needs IP address to function. After STB boot, one of the first things is to contact DHCP server and ask for IP address. DHCP server dynamically distributes network configuration parameters, such as IP addresses, DNS and NTP server address, or STB boot/upgrade server to the STB devices.
It is used for clock synchronization between computer systems over packet-switched, variable-latency data networks. It can be installed in the operator’s network or one of the Internet servers can be used. Usually, all solution components connected to the IP network as well as end user devices have NTP configured, in order to properly synchronize the time, otherwise some of the TV services such as EPG or nPVR, might not function properly.
It resolves domain names in the IP address. Service or server address can be configured as a domain name (e.g. googletv.com). In such cases, STB and other client devices need to have DNS server configured that will properly resolve domain name in the IP address.
Hopefully this article was useful and it will save you some time when you will start defining your new IPTV or OTT service. Even though it’s sometimes fun watching other people doing same mistakes you did, please share this article on the social networks with others that are looking for help in starting IPTV or OTT service.