The digital terrestrial television is the transmission of data (images and sound) via digital signals. DTTV signals are broadcast over the same media as the older analog terrestrial TV signals: via radio.
DVB-T is the standard for the broadcast transmission of the digital terrestrial television. It uses MPEG-2 codification and COFDM modulation. The bandwidth of DVB-T is 20Mb/s so, as much as 5 programs per channel depending of the quality wanted (4Mb/s to SD-TV and 20Mb/s to HD-TV). All the video, audio, subtitles and text programs conform the multiplex and it is coded through COFDM.
The advantages of DVB-T are the reduction of the bandwidth, clearer picture and superior sound quality, subtitles and different languages, and more contents. However, in Digital TV noise produces an increase in the channel bit error rate so the transmission could break down.
IPTV is a new way of understanding the tv, it is an interactive television accessible by multiple devices. The customer chooses what to watch at every moment so, only the channel ordered is transmitted in MPEG-2 or MPEG-4 (better quality and data rates) codification.
In Spain there are different IPTV providers: Telefonica (Imagenio), Orange (OrangeTV), Jazztel (Jazztelia TV). Nowadays, Movistar Imagenio is the most important with more than 800.000 clients.
Multimedia Home Platform (MHP)
DVB-MHP is an open middleware system standard designed by the DVB project for interactive digital television. Interactive tv applications can be delivered over the broadcast channel, together with audio and video streams. There are lots of application areas of MHP: program guide, portals for events and programs, information, news, weather, sports events, games, interactive shopping…
MHP applications are programmed using Java language and APIs, and once developed are installed on MHP set-top-boxes. However, the degree deployment of MHP is null at this moment.