Tag : IP

Connected TV

A television service that typically allows viewing recent programs and the internet in general. Early versions of this made use of a set-top box with an internet connection, today it can be accessed with an all-in-one smart TV.

See also: Smart TV

DASH

Dynamic Adaptive Streaming over HTTP, A.K.A. MPEG-DASH, makes use of standard HTTP (Hypertext Transfer Protocol – as in the internet) web servers to provide a high quality adaptive bit-rate streaming video service. As the video or audio is usually quite long, and a lot of data, it divides the content into small segments which are then sent as a series of small HTTP files. The server makes the content available in a range of bit rates so the receiver can select the highest quality version that provides continuous video or audio – no freezes or breaks. It also means that the service can adapt to fit with the available bandwidth as the speed of the internet connection varies.

DASH-IF is the DASH Industry Forum that is made up of 67 industry members from around the world.

DASH-PG is the Promoters’ Group. Its membership includes manufacturers, content owners, operators, and more. The goal is to promote DASH as a widely available solution for adaptive streaming.

DASH-VLC a Video LAN Player designed to work with DASH. Generally VLCs are available as downloads, and can play a wide range of video formats. A DASH-VLC is designed to work with DASH.

Website: dashif.org

DSL

Digital Subscriber Line. A general term for a number of techniques for delivering data over the telephone local loop (between exchange and user) – the copper wires that make up the so called ‘last mile’. Referred to generically as xDSL these offer much greater data speeds than modems on analog lines – up to 32 Mb/s upstream to the computer and 1 Mb/s or more downstream.

See also: ADSL

DSLAM

Digital Subscriber Line Access Multiplexer, usually located at the local telephone exchange, it connects multiple customer DSL lines to a high-speed ATM internet backbone line. It is the device that communicates with our ADSL (and SDSL) modems, creating a network similar to a LAN but without Ethernet distance restrictions, to provide an Internet connection for subscribers.

FTP

File Transfer Protocol. The high level Internet standard protocol for transferring files from one machine to another. FTP is usually implemented at the application level.

See also: FXP

HTTP

HyperText Transfer Protocol provides the basis for data communication in the World Wide Web. It defines how messages are formatted and transmitted, and how web servers and browsers respond to commands. So a web address (URL) entered in a browser sends an HTTP command to a web server that then requests fetching and sending the page found at that URL.

See also: DASH

HTTP Live Streaming (HLS)

This HTTP-based media streaming protocol enables live streaming of audio or video over the internet for appropriate Apple products. It is a part of iOS, OS X, QuickTime and Safari and works by dividing the required source media into small chunks of around two seconds, then offering media files in several levels of H.264 video and MP3 or HE-AAC audio compression, providing from low to high bit-rate (and quality) delivered in an MPEG-2 Transport Stream. The data delivery system is adaptive to allow for variations of available data speeds, with the receiving end able to choose the highest bit-rate files it can receive fast enough to maintain live operation.

See also: Buffering, Adaptive bit-rate streaming

IP

1) Intellectual Property – this can be very valuable and there are regular court cases where owners of this type of IP are trying to sue other people who they think have stolen their IP.

2) Internet Protocol – is the de facto standard for networking and is the most widely used of the network protocols that carry data and lie on top of physical networks and connections. Besides its Internet use it is also the main open network protocol that is supported by all major computer operating systems. IP, or specifically IPv4, describes the packet format for sending data using a 32-bit address to identify each of nearly 4.3 billion devices on a network with four eight-bit numbers separated by dots e.g. 192.96.64.1. Each IP data packet contains a source and destination address as well as a payload of data. There is now IPv6 which brings, among many other enhancements, 128-bit addressing – allowing 2128 addresses, plenty for all the connected devices on planet Earth, and thus relieving IPv4’s address shortage.

Above IP are two transport layers. TCP (Transmission Control Protocol) provides reliable data delivery, efficient flow control, full duplex operation and multiplexing – simultaneous operation with many sources and destinations. It establishes a connection and detects corrupt or lost packets at the receiver and re-sends them. Thus TCP/IP, the most common form of IP, is used for general data transport but is relatively slow and not ideal for video.

The other transport layer is UDP (User Datagram Protocol) which uses a series of ‘ports’ to connect data to an application. Unlike the TCP, it adds no reliability, flow-control or error-recovery functions but it can detect and discard corrupt packets by using checksums. This simplicity means its headers contain fewer bytes and consume less network overhead than TCP, making it useful for streaming video and audio where continuous flow is more important than replacing corrupt packets.

There are other IP applications that live above these protocols such as File Transfer Protocol (FTP), Telnet for terminal sessions, Network File System (NFS), Simple Mail Transfer Protocol (SMTP) and many more.

Video over IP – Watching video over the internet is commonplace. It represents a very large, and growing, part of internet traffic, and fits well with the rising population of Smart TVs. There are several suitable streaming protocols in use, including those offering variable bit rates such as HTTP Live Streaming from Apple, and HTTP Smooth Streaming from Microsoft. These offer a good chance of providing uninterrupted viewing, even when the internet connection gets a bit slow.

Website: www.ipv6forum.com

IP Datacast Forum (IPDC)

The IPDC (Internet Protocol Data Cast) Forum was launched in 2002 to promote and explore the capabilities of IP-based services over digital broadcast platforms (DVB and DAB). Participating companies include service providers, technology providers, terminal manufacturers and network operators. The Forum aims to address business, interoperability and regulatory issues and encourage pilot projects.

See also: IP over DVB

Website: www.ipdcforum.org

IP over DVB

The delivery of IP data and services over DVB broadcast networks. Also referred to as datacasting, this takes advantage of the very wideband data delivery systems designed for the broadcast of digital television, to deliver IP-based data services – such as file transfers, multimedia, Internet and carousels, which may complement, or be instead of, TV.

Due to DVB-T’s ability to provide reliable reception to mobile as well as fixed receivers, a new standard DVB-H has been added to send IP-style service to people on the move – typically to phones. For interactivity, a return path can be established by the phone.

See also: IP Datacast Forum, Data carousel

IPTV

Internet Protocol Television refers to the use of the IP packetized data transport mechanism for the delivery of streamed realtime (live streaming) and downloaded television signals across a network. This is a huge subject as video accounts for an increasingly large part of internet traffic. Cisco predicts that, excluding video peer-to-peer file sharing, 79 percent of domestic internet traffic will be video by 2018, up from 66 percent in 2013. And that including file sharing, it will take between 80-90 percent of global consumer traffic in 2018.

Website: www.cisco.com

MHP

Multimedia Home Platform – DVB-MHP is open middleware from the DVB project for interactive television. It enables the reception and execution of interactive, Java-based applications on a TV set that can be delivered over a broadcast channel, together with the audio and video streams. The applications can provide information services such as games, interactive voting, e-mail, SMS and shopping. Some may require using an IP return channel.

Early deployments included DVB-T in Italy, DVB-S in Korea and Poland and DVB-C in Belgium. There have also been trails in other countries.

Mobile TV

This is where broadcasters and mobile (cell) telcos come together to provide consumers with access to video content on their mobile phones and tablet computers. This includes downloads to flash memory, 3G and 4G streaming and mobile on-demand broadcast TV. The landscape is complex as there are many competing formats including DVB-H, DVB-SH, MediaFLO, ISDB-T, S-DMB/T-DMB in different regions and backed by different hardware manufacturers, technology suppliers, content providers and mobile operators. Also there are any number of screen resolutions and aspect ratios to be catered for. China is adding its homegrown China Multimedia Mobile Broadcasting (CMMB). In Europe, the European Union has decided to support the DVB-H standard for mobile TV. DVB-H uses a separate broadcast network, rather than a phone network, to send TV content to phones or mobile devices.

Modem

Short for modulator/demodulator, it is a two-way communications interface working between a communications channel, such as a DSL line, and a machine such as a computer. That is how billions of people access the internet. Television itself is distributed live via a modulator in the transmission chain, and a demodulator at the receiving end.

The efficiency of modern modems over analog is worth noting. In analog days it generally used PAL or NTSC ‘coding’, that compressed three channels R, G and B into one, which was transmitted in one TV channel. Today there are very efficient compression systems such as MPEG-2, MPEG-4, H.264 and H.265 used in DVB, ATSC or other digital systems. The combination of the latest video compression, H.265, and the efficiency of DVB-T2 modulation will allow up to 32 SDTV channels, or 4 HD channels, or one 4K UHD channel, to be delivered in the space (bandwidth) that was occupied by one analog PAL 625-line channel.

OTT

Over-The-Top (content) refers to video and audio that is delivered over the broadband internet without involving broadcasters of cable, satellite or terrestrial television systems. The provider may be aware of the content but is not responsible for it, or in control of it.

See also: IPTV

SNMP

Simple Network Management Protocol is the Internet standard protocol developed to manage nodes (servers, workstations, routers, switches, hubs, etc.) on IP networks. It enables network administrators to manage network performance, find and solve network problems, and plan for network growth. SNMP works by sending Protocol Data Units (PDUs) messages to different parts of a network. Agents, SNMP-compliant devices, store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters.

Streaming (video and/or audio)

Refers to supplying a constant realtime media service. Although broadcast TV has done this from the beginning, and SDI streams data, the term is more usually associated with delivery by networks, usually the Internet where it accounts for a large majority of the traffic. The transmission comprises a stream of data packets which can be viewed/heard as they arrive though are often buffered, stored slightly in advance of viewing/hearing, to compensate for any short interruptions of delivery. For the Internet, media is compressed and generally offers acceptable results for audio and video. There are three predominant video streaming solutions: RealNetworks with RealVideo, RealAudio and RealPlayer, Microsoft Windows Media and Apple QuickTime; each with their particular advantages. As Internet transfers are not deterministic, pictures and sound may not always be continuously delivered.

Many popular sites, such as YouTube and the BBC iPlayer, offer both SD and HD services. A few are working with 4K UHD. Most TV and radio stations offer live streaming services.

See also: IPTV, File transfer, Isochronous

Switch (network)

Connecting network users via a switch means that each can be sending or receiving data at the same time with the full wire-speed of the network available. This is made possible by the aggregate capacity of the switch. So, for example, an eight-port Gigabit Ethernet switch will have an aggregate capacity of 8 Gb/s. This means many simultaneous high-speed transactions taking place without interruption from other users. The Internet is connected by thousands of very high speed network switches.

See also: CSMA/CD, Hub

TCP/IP

Transfer Control Protocol/Internet Protocol. A set of standards that enables the transfer of data between computers. Besides its application directly to the Internet it is also widely used throughout the computer industry. It was designed for transferring data files rather than large files of television or film pictures. Thus, although TCP/IP has the advantage of being widely compatible it is a relatively inefficient way of moving picture files.

See also: FTP, IP

WiMAX

Worldwide Interoperability for Microwave Access (IEEE 802-16 and ETSI HiperMAN) uses OFDMA modulation over its radio links. The WiMAX Forum describes it as “a standards-based technology enabling the delivery of last-mile wireless broadband access as an alternative to cable and DSL”. Unlike Wi-Fi, this offers symmetrical bandwidth (equal upload and download speeds) over longer ranges of some kilometers with strong encryption (3DES or AES). It connects between network endpoints without line-of-sight of the base station for fixed, portable and mobile wireless broadband. A typical cell radius is 3-10 km, offering up to 40 Mb/s per channel for fixed and portable access, and up to 1 Gb/s for fixed only.

Mobile networks are expected to provide up to 15 Mb/s capacity within a 3 km cell radius. WiMAX technology is incorporated in some mobile devices, allowing urban areas and cities to become MetroZones for portable outdoor broadband wireless access.

See also: OFDMA

Website: www.wimaxforum.org