In contrast to traditional broadcasting, many different bodies are working on IPTV services. To date, there has been little standardization even within individual countries. There is a growing industry consensus that IPTV should be reserved for those services provided directly by the network operator who owns and operates the last mile, i.e. the last connection to the user’s premises.
Either multiprogram (MPTS) or single-program (SPTS) MPEG-2 transport streams encapsulated in IP packets are used to carry video and audio in a similar way to conventional broadcasting services using standard codecs such as MPEG-2, H.264 or VC1 at SDTV or HDTV resolution. IPTV may employ multicast services when, for example, re-broadcasting a live local terrestrial channel and for popular scheduled or live services. IPTV operators can also use unicast delivery protocols to set up a specific path from the playout server direct to an individual set-top box.
Numerous protocols can be used to move video over an IP network. Choosing the right ones is largely a commercial decision driven by the degree of access that the service provider has to the consumer.