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Digital TV –
where to from here?
Freeview with MPEG-4
should be the answer!
Digital TV commenced in Australia on 1st January 2001
– yes, nine years ago, making Australia one of the first
countries to start regular DTV transmissions. These
transmissions now cover 60% of the population but for
Australians to get full HD programming, we need MPEG-4
broadcasts. At present, we are being short-changed.
By ALAN HUGHES
W
hat has happened with Digital TV since 2001? As far as
programming is concerned,
the answer must be “Not much!”
Sure, the networks can now transmit both SD and HDTV but there is
little that is true HD - and most HD
is merely simulcast with the SD programs anyway. Believe it or not, a lot
of the do-called “HD” programming
is itself up-scaled from SD, which
means that it might fill a large screen
but quality-wise, it’s no better than the
SD program.
We’ll explain the important difference between HD and true HD (or more
correctly Full HD) shortly.
However, on the reception side,
there have been considerable developments. Over the last few years, a
large proportion of the population has
upgraded their TV sets to large-screen
LCD or plasma HD sets. Many people
have also purchased Blu-Ray players
which are recorded at the ‘Full HD’
standard. When connected to a display
with an HDMI or component video
You don’t have to pay a lot to get Freeview Certification (whatever that actually means – Freeview won’t tell anyone!).
This HD Set Top Box was recently being offered through ALDI stores for just $99 – and that includes MHEG-5 interactive
middleware enabled, MPEG2 and MPEG4 AVC format decoding and 1080i/720p/576i display modes.
18 Silicon Chip
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cable, many large-screen TVs and projectors will display the image at this
quality. But free-to-air broadcasters
and Pay-TV operators do not transmit
signals at the ‘Full HD’ standard.
Freeview
We’ve also been “blessed” with a
raft of “new” digital TV programming
under the “Freeview” banner but as
viewers well know, that hasn’t meant
much in the way of new programs.
In fact, during 2009 TV channels
were forced to change their advertising which claimed Freeview offered a
whole lot more than it delivered.
With only a few exceptions, most
new Freeview channels are simply
copies of existing channels.
As we said earlier, Australians are
being short-changed and there is no
sign that this is going to change any
time soon. But Freeview is more than
TV stations transmitting new digital
channels. It’s actually a whole new set
of technical standards including (but
not limited to) the ability to receive
MPEG-4 signals.
It’s almost impossible to find out
what the Freeview specifications are,
unless you are a manufacturer or importer willing to sign a non-disclosure
agreement.
However, even without the specifications, we can use the Freeview
marketing and labelling to ensure any
TV set purchased now will be ready
for MPEG-4 when it finally arrives.
What is MPEG-4?
The Motion Picture Expert Group
(MPEG) is a body which lays down
standards. Australian Free-to-Air TV
and SD satellite TV currently use the
MPEG-2 standard.
In 2007, MPEG-4 was introduced,
which creates signals with 30 – 50%
smaller data rates than with MPEG-2.
The result is that a Full HD signal can
now be sent with a data rate of only
8Mb/s.
MPEG-4 is presently used only on
HD satellite transmissions including
Foxtel, handheld TV, plus a number
of Free-To-Air (FTA) ground-based TV
services, including all New Zealand
DTV.
Semiconductor manufacturers are
now making MPEG-4 decompressor ICs. These will also decompress
MPEG-2 because it is a subset of
MPEG-4. As a result, there should
be no significant increase in receiver
price due to the inclusion of MPEG-4
decoding.
For example, Aldi stores have been
selling a Freeview-approved STB for
a similar price to other, non-MPEG4-capable, HD STBs.
TV precedents
When colour TV was introduced
to Australia, there were no separate
monochrome and colour transmitters.
All receivers, even B&W sets, could
display a watchable program from the
same transmission.
The former equivalent of the ACMA
specified that all colour receivers had
to incorporate a delay line for colour
correction. As a result we had no
simple-PAL sets and assuming there
No money for MPEG-4?
Free-to-air TV stations constantly bleat
about insufficient revenue to allow them
to adopt new technology such as MPEG-4.
But with the Federal Government’s $250
million largesse to free-to-air licencees
in the form of slashed licence fees (The
Australian, February 8), surely there is
now just a little left in the coffers to stop
short-changing Australian TV viewers and
switch on MPEG-4?
was enough signal at the aerial, all
colour sets gave good pictures.
Similarly, when UHF TV was introduced, even if the TV receiver didn’t
have a UHF tuner (and very few did
not) just about everyone had a VCR. All
video recorders were equipped with a
UHF tuner allowing the vast majority
the audience to view UHF as well as
the original VHF programs. This enabled all broadcasters to roll-out UHF
transmission to many regional areas.
But now, with digital TV, we have
separate HD and SD program streams.
They could have completely different
content but for the most part, they both
have identical programs.
Since HD broadcasts started, the
price of HD set-top-boxes has plummeted; SD STBs have virtually disappeared from the shops. (Even if SD are
still available from your local retailer,
we recommend against purchasing
them – even if they appear to be an
absolute bargain!)
Action required
What we need now is for the Depart-
Here are the developments since 2001. The inner (yellow) rectangle represents the standard CRT screen, capable of
displaying only SD (standard definition) pictures. Unfortunately, many of the signal sources even today – including offair “HD” TV signals – are only capable of displaying at this resolution. This will change – but it needs to change faster!
siliconchip.com.au
March 2010 19
compression and improved error correction. Foxtel HD is already using
DVB-S2. This has enabled them to
minimise their satellite hire costs for
HD programs.
The conversion task
in Australia
A comparison of relative screen sizes from SD, through the various incarnations
of “HD”, right up to the full or true HD (in light blue). As this graphic ably
demonstrates, even discounting SD, without full HD you are being well and
truly shortchanged. And you cannot (yet!) receive full HD signals off-air.
ment of Broadband, Communications
and the Digital Economy and the
Australian Communication and Media
Authority to insist all importers that
all receivers must be able to produce
a viewable program from a Full HD
MPEG-4 program.
To enable broadcasters to switch
over to MPEG-4 receivers need to be
able to decompress all MPEG-4 signals,
whether they are Full HD or SD. This
will then make the need for transmitting an identical SD version of the HD
program unnecessary.
Even though MPEG-4 offers broadcasters a number of advantages (see
tables), experience has shown they
loathe spending money: they won’t
switch over to MPEG-4 until they are
confident that receivers can decompress all MPEG-4 signals.
As an aside, in the USA, all colour
TV transmissions were to the NTSC
standard until 2007. Now NTSC broadcasts have stopped and US TV signals
are HD ASTC digital only. So while the
USA started digital TV after Australia,
they have moved ahead of us with their
HD ASTC digital TV.
As a result, there has been a considerable increase in the number of
HD original programs – which we
don’t see! So plenty of HD programs
are available and probably most USoriginated TV series we are presently
watching are available in HD – at no
extra cost!
So, to set the ball rolling, we need
just one TV broadcast network to start
transmitting MPEG-4 programs. The
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others will follow suit just so they
don’t suffer any marketing disadvantage.
Developments since 2001
Currently, we have a model of three
commercial broadcasters plus the
ABC & SBS. Usually this means five
transmitters on five separate channels.
Digital TV is more efficient in the use
of the spectrum, enabling more than
one program to be transmitted by a
single transmitter. Local digital TV stations are now radiating extra program
streams: TEN and One HD, Nine and
GO!, Seven and Seven HD, while the
ABC now has ABC2 and ABC3 with
SBS also transmitting SBS2.
Costs for the broadcasters
Provided the entire audience can
receive the MPEG-4 programs, the
largest cost is the infrastructure used
to produce HD programs. The distribution costs are unchanged with
the exception of the purchase of HD
MPEG-4 compressors for each program
stream at the playout centre.
Satellite television
Currently the Optus Aurora satellite is feeding low powered repeater
transmitters and direct-to-home receivers in remote areas of Australia.
This system is DVB-S which uses SD
MPEG-2 compression.
Towards the end of this year the
Optus D3 satellite will be launched.
To transmit HD through a satellite
DVB-S2 is required as it uses MPEG-4
There are about 7.9 million dwellings in Australia. There are 4.2 million
dwellings yet to get their first digital
receiver.
Australia has around 17 million TV
sets. Eight million of those sets need
to be replaced or at least, used in conjunction with a Set Top Box.
The Switchover Taskforce of the
Department of Broadband, Communications and the Digital Economy
(DBCDE) is funding set top boxes
for aged, disability, DVA pensioners,
along with carer and DVA income
support recipients.
The Tender should mandate that
only MPEG-4 capable Set Top Boxes be
supplied, and where satellite receivers
are required, they must be DVB-S2.
For reliable DTV reception the tender
should also mandate that no antennas
designed for any channel between
channel 0 – 5A can be supplied.
This means that by the start of 2014
at least 53% of households will be able
to view HD MPEG-4 signals. Some
current DTV viewers will need to feed
their digital TV with an MPEG-4 capable Personal Video Recorder or STB
because their existing decompression
is only capable of MPEG-2. You may
have noticed that HD Set Top Boxes
are now 10% of the price they were
in 2001.
Country Western Australia has no
commercial DTV. GWN (Prime WA)
and WIN are yet to announce a commencement date. Since they only intend to have one digital transmitter per
site then the use of MPEG-4 would give
either Full HD TV or a greater variety
of SD programs. Without commercial
DTV there is a much lower proportion
of digital TVs. With a viewing population of 500,000 this would be a good
place to start using MPEG-4.
The ABC’s Role
Virtually all of the programming on
ABC HD is upconverted ABC1. This
does not make the image quality any
better than ABC1. The commencement of ABC3 (Childrens channel)
would have spread the existing data
rate too thin.
siliconchip.com.au
So the ABC would be better off
converting ABC HD to Full HD using MPEG-4. This would require an
MPEG-4 encoder for each state so that
the local news will be available on
ABCHD so the channel doesn’t need
to be changed. Even better if they also
use an additional MPEG-4 compressor
for ABC3. This will accelerate the sales
of MPEG-4 capable receivers.
Conclusion
To future proof TV all new receivers must:
• be able to display a full HD MPEG-4
program
• have at least 1 HDMI V1.3 input,
and STB/PVRs an HDMI output
• be MHEG-5 capable
• be 24p display capable (Blu-Ray
compatible)
• All Australian satellite transmissions should be DVB-S2 to enable
all of us to have the option of Full
HD TV.
Importers and manufacturers need
to indicate in the specification section of the User’s Manual and on
their websites what their receivers are
capable of.
Broadcasters and the regulators
need to bite the bullet and start limited
Full HD transmissions with a view
to a complete conversion to MPEG-4
transmission at the start of 2014, the
start of all digital transmission. This
includes the Optus Aurora Free to Air
satellite service, which is also used to
feed many country transmitters.
If DVB-S2 is used then the demodulated satellite signal can be fed into
the ground based transmitter without
the need for changes in compression.
Now that the major US networks are
HD capable to their viewers and the
Europeans are starting HD transmissions, it is time that our broadcasters
use the HD versions of programs where
possible.
We now have the situation in Australia where an increasing percentage
of the audience have better performing
equipment than the broadcasters. The
lack of Full HD broadcast programs
is making manufacturers and retailers’ claims of excellent quality false
(except for Blu-Ray disc playback).
What is needed is a decision from
the DBCDE and Freeview for a start
date for the above and an instruction
to all importers and manufacturers to
implement it. This follows the precedents they set in the past.
SC
siliconchip.com.au
Which set to buy?
If you are in the market for a TV, PVR or set top box, which model should you buy?
The best answer is to buy one labelled “Freeview Approved” since all such products
are capable of MPEG-4 decompression. This applies to all Australian and New Zealand
“Freeview Approved” models.
Another option would be to look for the Standards Australia ticks, unfortunately the
“Australian Standard 4933.1 – 2009 Digital television - Requirements for receivers - VHF/
UHF DVB-T television broadcasts” draft has been placed on hold by Standards Australia,
pending the availability of resources. This standard is not mandated by law.
You could also look in the specifications section of the user’s instruction manual,
however many manufacturers do not specify what compression standards the device
can decompress. Download the manual from the manufacturer’s website or look at the
manual in the store.
Contact the manufacturer or importer and ask them.
Which receivers are currently capable of MPEG-4 decoding?
The European Union is proposing that all DTV receivers sold after 1st January 2012
should be able to decode MPEG-4 also called H.264/MPEG-4 AVC standard.
TV Receivers
Blue =
MPEG-4 capable
Black=
24p capable
Cyan =
Full HD
Orange =
>1m diagonal screen
Set Top Boxes and Personal Video Recorders
Blue =
MPEG-4 capable,
Yellow = HD
Cyan =
HDMI capable
The data for the above graphs is constantly changing so some brands may be missing
or have a greater percentage of the characteristics shown in the graph. The data was
obtained from a survey of websites, including downloading the instruction manuals
and requests for information from the manufacturers. Most did not reply.
March 2010 21
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