Digital TV: Connecting the unconnected?

The South African Department of Communications (DoC) upset the industry and delayed the migration to digital television earlier this year when the temporarily reinstated Director General Mamodupi Mohlala stated that a standard for digital terrestrial television (DTT) broadcasts hadn’t been selected.

MultiChoice,, the Southern African Digital Broadcasting Association (SADIBA) and South African Communications Forum (SACF) have all publicly opposed the DoC’s position, citing the Broadcasting Digital Migration Plan (BDMP) published by the DoC in 2008 as well as the migration regulations released by ICASA earlier this year.

The BDMP stated that Digital Video Broadcasting – Terrestrial (DVB-T) would be South Africa’s DTT standard. According to industry stakeholders this policy decision wasn’t unilateral, but came over the course of eight or nine years after two separate recommendations for the European DVB standard where made by different government-appointed bodies.

While there are a number of other DTT standards, most industry players believe that the standards debate is really about DVB-T and the Brazilian version of Integrated Services Digital Broadcasting, Terrestrial (ISDB-Tb). ISDB-T was originally developed in Japan, but was customised in Brazil to create ISDB-Tb.

One of the key features punted by the Brazilians is the interactivity capabilities of their version ISDB-Tb.

DTT Interactivity and Middleware

The Brazilians have developed their own open source interactivity middleware called Ginga. In South Africa, broadcasters have tested a similar but somewhat different technology on DVB-T called MHEG-5.

Aldred Dreyer, an expert in the industry on DTT, explains that middleware simplifies communication between the interactive software and the hardware of the digital TV set top box (STB).

An STB is similar to M-Net or DStv decoders in that consumers will need to connect a DTT STB to their normal TV sets in order to receive digital TV signals.

Special Advisor to the Civil House at the Presidency of Brazil, Andre Barbosa Filho, mentioned at a business forum earlier this year that interactivity should be a fundamental factor in considering a digital broadcasting standard.

Filho went on to say that he thinks the statement that the PC will be the point of integration in a home is European propaganda. Filho suggested that DTT is a way to bring the information age to those who have been unable to afford computers and Internet connections.

This begs the question: Is the interactivity offered by digital television a viable substitute for an Internet-connected PC?

Dreyer explained that there are essentially three types of interactivity available on DTT standards such as DVB-T:

  1. Local interactivity – Users interact with data stored in the STB. Examples of this include electronic programming guides (EPG), games stored in the STB, and applications like dictionaries.
  2. Pseudo interactivity – Users interact with the broadcast stream. When a show or sporting event is over the data becomes unavailable. Examples of this include pressing a particular button to access the data broadcast associated with football, rugby, or cricket matches, as well as shows like “Idols.” DStv subscribers may also be familiar with the games that are perpetually broadcast on certain channels.
  3. Return path interactivity – Users send data back to the broadcaster, content provider, or a third party. Examples of this include shopping from your TV (“T-shopping”).

DStv and TopTV subscribers may be familiar with local and pseudo interactivity as the satellite television offerings in South Africa are both based on DVB standards that already make use of them.

Return path functionality is required in order to provide a web-like experience over digital TV.

Dreyer said that a return path is provided by a dial-up modem. Typical examples of this are POTS/PSTN (i.e. old 56k dial-up), ISDN, or GSM/GPRS modems.

As part of the implementation of DVB-T in South Africa a South African profile of MHEG-5 was created, Dreyer explained. This profile doesn’t currently include return path capability, but adding it is “just a software upgrade” that can be delivered over the existing DVB-T data channel.

The specification published by the SABS for the South African set top boxes based on DVB-T also includes a USB port which can be used to connect a modem, said Dreyer.

Internet over TV the answer for the unconnected masses?

Dreyer said that for basic “wow-factor” interactivity you don’t need a return path.

Even when a return path is present, Dreyer warned that websites and television are two different things.

Besides text being displayed at different sizes on television screens and computer monitors, Dreyer said that content on websites would have to be repurposed for use on television.

PCs typically have a keyboard and a pointing device such as a mouse for navigation and input whereas television users would have to navigate around a page with the direction keys on a remote control.

Gerhard Petrick, who is active within the technical committee of SADIBA, also mentioned the challenges of delivering web content over television screens via set top boxes.

“In an age where the link between increased economic activity and access to a broadband connection is undisputed, arguing that digital terrestrial television with interactivity will provide for ‘connected homes’ would be tantamount to arguing in favour of an apartheid style Bantu education system that deliberately offered substandard education to people,” said Petrick.

“While the roll-out of DTT will provide for new interactive services and return path connections,” Petrick said, “DTT, regardless of the technology standard, will not deliver connected homes or proper internet access.”

The use of digital broadcasting as a substitute for a proper Internet connection also seems to be in conflict with the DoC’s recently published National Broadband Policy. It stipulates that all South Africans must have access to an “always available, multimedia capable connection with a download speed of at least 256 kilobits per second (kbps)” by 2019.

MHEG doesn’t need much data capacity. One of the local DVB-T trials is testing MHEG applications using 500kbps, said Dreyer. While the data channel capacity is configurable, the capacity is shared by all television consumers receiving content from a particular multiplex.

Under the current Digital Migration Regulations published by ICASA the SABC will operate one multiplex while and MultiChoice will share another.

Ready to go

Filho said that the Brazilian government would assist in training and skills transfer if South Africa chooses to adopt ISDB-T.

Representatives of MultiChoice,, SADIBA and SACF have all said that digital broadcasting could begin in six to nine months if the DoC decided to stick with DVB-T for which policy, regulations, SABS specifications, band plans and trial networks already exist in South Africa.

DTT interactivity a viable alternative to PC literacy and Internet access? << can it bridge the “digital divide?”

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Digital TV: Connecting the unconnected?