Introduction:
The coming launch of ‘Freeview HD‘ will doubtless have implications for retailers as well as consumers and in this note I hope to help address some of the questions. There are several new features which are implemented in ‘Freeview HD‘ which might impact consumer and some less obvious features you might not know about.
New features:
This is a new type of transmission technology which has evolved from the existing DTT standards and next generation communications theory.
Using the more recent developments from MPEG using the H.264 compression method the video can be transmitted in as little as 25% of the bandwidth that would be required for the same type of transmission in MPEG2. This allows HD which would consumer substantially more bandwidth to be transmitted efficiently.
MHEG is the standard for interactive services in the UK and is a very light weight system. It failed to impress some people in it’s original form but substantial progress has been made in the last few years to delivery a much more powerful user experience. The speed and graphics quality has been enhanced and the implementation on Freesat has already proven popular with consumers. As time passes the developers are able to demonstrate further enhancements in graphics performance and quality. The most significant step is in being able to render graphics to the screen with HD resolutions.
This allows MHEG applications to communicate back to the broadcasters over the consumers broadband package. This potentially gives consumers access to interactive voting, a wider range of content than can be broadcast and even streaming catch-up television. Broadcasters will decide what services they will implement but the connection is available to consumers on their product for those future services.
All products are now expected to be capable of audio description, this system allows people with visual impairments to have a description of the programme they are watching. TV is popular with a wide range of people and we are looking to include as many groups as possible. It will even work on HD channels, so the whole family can enjoy the latest releases. Some products may not support mixing multi-channel surround sound with AD tracks to produce surround out, but AD will still work with surround but produce a stereo output.
In addition to supporting existing Teletext format subtitles and standard DVB format subtitles the new boxes should now support HD format DVB subtitles which provides decent subtitles for HD video broadcasts.
Less obvious features:
The broadcaster can signal that a programme is also available in HD so that a viewer can get the best quality version even when watching the SD channel.
Broadcasters have difficulties obtaining rights for some programmes to be broadcast in HD on free television. So in order to be licensed by ‘freeview’ the manufacturer must agree to record the broadcasts subject to rules that are transmitted by the broadcaster for each programme. It is possible for the broadcaster to signal that they will not permit the programme to be copied or that it may only be copied once. They may also indicate that the programme can be streamed or copied to DVD. The ability to archive and copy programme content is not a requirement but where it is implemented it must follow the broadcast rules.
- Network Change Notification
The transmitter network can signal when changes are going to happen, this way when a re-tune is needed the receiving device can react more intelligently than they currently do.
A broadcaster can use new signaling on both programs and channels to indicate that their broadcasts contain content which may might not be appropriate for certain viewers. It is not intended just as an “Adult” genre but it is designed to show a wide range of sensitive issues, possibly including photosensitive epilepsy and violence.
Questions:
- What type of antenna does Freeview HD device need?
Freeview HD uses a traditional UHF antenna as used by existing terrestrial television.
- Will I need a new antenna for DVB-T2?
No, not unless you don’t get a good signal level currently. The T2 transmissions are being designed to perform under equal conditions as the existing digital transmissions but with more bandwidth to put more information in.
- What does DVB-T2 provide to broadcasters/consumers?
The development of DVB-T2 was not just about the steady march of time but has been done to provide more data in the available bandwidth. This means that the broadcasters can send more information per transmitter. DVB-T already allows many channels to exist in the same equivalent
- I have a High Definition ready TV, will it support Freeview HD?
Freeview HD requires the product to support the DVB-T2 transmission standard, only products made on/after winter 2009 and which say they support “Freeview HD” will work with the new service. All current IDTVs will need an external set-top box device to be able to receive Freeview HD. The current definition of “HD TV Ready” does not cover the new UK standard for HDTV.
- Can I upgrade my receiver to support T2?
It is not possible to software upgrade any existing products to support DVB-T2 due to the significant differences between the platforms. In theory certain IDTV displays from certain manufacturers may be upgraded by replacing certain parts of the hardware, but no manufacturer has yet stated their intention to do this.
- When will broadcasts of HD services start?
No dates have yet been confirmed, but it is expected that in preparation for product being available broadcasts are expected to begin during Winter of 2009. This schedule may change in response to changes in conditions and consumers should not expect to have reception before 2010. The service will have limited coverage to begin with and only certain areas will have availability to begin with. Consumers should check their coverage to determine what services are available in their area. It may be that a product like the Foxsat-HD or Foxsat-HDR (using the Freesat service) is the best way to get access to free HD channels.
- When will product be available for Freeview HD?
While the technology of HD has been available for some time the variations required for the Freeview HD, particularly DVB-T2, will require significant work. Because new silicon chips must be designed for this service there needs to be careful work on this investment.
- How many HD channels will be available?
There will be an HD service from the BBC and other services are expected from ITV-HD and Channel4 HD. Eventually a fourth and perhaps fifth HD provider are expected to join the platform. The platform operators are aiming to upgrade the video encoders to improve their efficiency in order to maximise the volume of content available on the platform for the available capacity.
Further definition:
A working group of the European DVB organisation has evolved this new standard for transmission. This has allowed more data to be broadcast in the same terrestrial spectrum. This is achieved by using powerful error correction technology as well as learning quite a number of lessons from the work on DVB-T. It has been many years since Digital Terrestrial Television was first launched in the UK and in this time the engineers/scientists have studied the different parameters available to engineers then this time has highlighted areas for improvement. The change in error correction is based on some mathematics which was first used in DVB-S2 and has now been refined further for DVB-T2. Overall the system is exploiting the next generation of technology and the latest innovations in transmission/communications theory.
A multiplex is the container which is used to broadcast digital services. The UHF radio frequency ‘channel’ in which a single analogue service was broadcast in can now be occupied by a multiplex which can contain many digital television services. There are currently six multiplexes in the UK which carry all of our digital television viewing. Each multiplex can carry services of differing quality averaging between eight and fourteen video services.
Bandwidth is the measure of size of the information carried, the term can be used in analogue or digital environments. In analogue it is the number of Hz and in digital it is the number of bits per second (the rate at which data is carried through a system).
- High Definition (HD) video:
Currently used to define any superior resolution of video over 720×576 in pixels.
