Media Reports
Blu-ray versus Blue Laser
By Barry Fox
Multimedia Manufacturer, Jan/Feb 2006
The rival DVD laser disc formats are
set to collide head-on
The rival Blu-ray and HD-DVD blue laser disc formats are still
on course for head-on collision. The disc structures are too different
to combine, and neither side is yet willing to roll over and admit
defeat---even if it is wrapped up in weasel words like "a single
format combining the very best of both formats." It's a straight
choice between HD-DVD's two half-thickness discs bonded back to
back and Blu-ray's full thickness disc with 0.1mm optical skim on
the top.
Market research recently carried out by Ipsos-Vantis for the HD-DVD
group shows that if there is a VHS-Beta format war, nearly half
of all consumers will simply not buy into either format. So either
one format will quickly fail or both will fail. With them will go
plans to use blue laser discs for hi-fi audio recording. More and
more home audio/video systems will use hard discs.
At the recent DVD Forum meeting in Paris we sat bewildered as Forum
member companies, and market research company Understanding and
Solutions which had organized the event, talked only about the new
HD-DVD system.
"The elephant's in the room, and no-one wants to notice"
said one delegate, "and it's called Blu-ray."
The main mention of Blu-ray was when Microsoft (those wonderful
people who gave us crashing Windows) launched into a clumsy slag-off.
None of the conference predictions for blue laser high definition
disc take-up, and none of the comparisons with DVD take-up, took
into account the devastating effect a standards battle will have
on sales for both new systems. Does the Forum not remember that
DVD was sold as a single system, because the format fight between
Toshiba, Sony, and Philips was settled ahead of launch?
There is still no sign of the only sensible compromise between
Blu-ray and HD-DVD---a single format disc based on Blu-ray's high
capacity, but with the iHD interactive system that makes HD-DVD
demos look so appealing.
Perhaps the Forum and co. genuinely believe that if they pretend
that Blu-ray does not exist, and has not been winning Hollywood
support over HD-DVD---even from Warner---then Blu-ray will just
go away. Or perhaps they just take us for fools. Significantly there
was very little opportunity for delegates to ask open questions
and challenge the contentious opinion that was being paraded as
fact.
The bottom line is that---especially in Europe, where PAL DVDs
can deliver very high quality pictures---any blue laser HD launch
will be a slow burn. If Blu-ray and HD-DVD launch head-to-head in
a format war, many consumers will just ignore both blue laser systems.
In the short term this will be great for DVD sales. But in the longer
term the video industry needs blue laser to fight piracy.
Both blue laser systems will use the same very strong copy protection
system called AACS (Advanced Access Content System) and the most
exciting thing to come out of Paris was the news that AACS can be
used to control camcorder piracy---currently the source of most
pirate DVDs.
The new---and very clever---idea was unveiled by Alan Bell, formerly
with IBM and now head of technology at Warner Bros. Although a boffin
[a person involved in research, according to Oxford Dictionary---Eds.],
Bell is a plain-talker: "If you want an easy way to remember
the names of the companies that developed AACS, without having to
remember Disney, Intel, Matsushita/Panasonic, Microsoft, Warner,
IBM, Toshiba, and Sony, just think of the their initials. DIMMWITS
is easy to remember."
The eight companies are far from dim, though. Their new camcorder-killer
very cleverly relies on sound, not vision.
Blue laser players will have a sensor that looks for inaudible
watermark sounds that will be buried in the soundtracks of film
prints released to cinemas. The mark is made by slightly varying
speech and music so as to convey a digital code. The variations
are too subtle to be noticeable to the human ear, but are easily
recognized by a sensor in the player which knows what patterns to
look for.
If the home player detects a telltale code pattern in a disc, the
disc must be an illegal copy made by copying a film print, or pointing
a camcorder and microphone at a cinema screen. So the player shuts
down.
This will work even when the pirates play their trick of tapping
into the hearing aid loop used in some cinemas to help deaf viewers.
In fact because the sound quality the pirates get from the hearing
loop is better than with a microphone, the watermark should be even
clearer on the pirate soundtrack and work even better!
The intriguing spinoff from this is that because new HD-DVD players
will also be able to play ordinary DVDs, the anti-camcorder system
should also be able to stop the player playing pirate DVDs. The
software that PCs use to play ordinary DVDs can also be modified
to look for watermarks.
A clever variation of the system can even prevent the playback
of copy discs made by pointing a camcorder at a high quality home
screen while it is playing a legitimate disc. Legitimate new movie
disc releases will have a "consumer" audio watermark,
which differs from the cinema mark. If an HD-DVD player senses the
consumer watermark it will check whether the disc was factory-pressed
and, if not, shut down.
Alan Bell reckons the Forum has done all it can to prevent foul-ups.
"We know that there might be a Hollywood movie in the background
during a children's party, and if Dad takes a home movie the watermark
might end up on the soundtrack," he says. "So the player
will only shut down if the mark sound is continuous for quite a
long time."
The beauty of all these new systems is that they hit the pirates
through the people who buy pirate discs. When Joe Sixpack has bought
a couple in the pub and found they stop playing five minutes into
the action, he will be a lot less keen on buying any more.
Before we all get too excited though, remember that some of the
studios currently pinch pennies by not using Macrovision or DVD's
own built-in protection systems to stop people copying DVDs to blank
discs or PSP Memory Sticks.
Likewise Macrovision has a newer system called RipGuard which is
designed to stop computer-experts using PCs to copy DVDs. But so
far only a very few titles have used RipGuard, for instance, "Million
Dollar Baby" and "Coffee and Cigarettes" in Germany.
"Madagascar" looks as if it will be the first in the UK.
So, just because blue laser players offer the chance to attack camcorder piracy, there is no guarantee the studios will pay to use it.
DIGITAL RADIO
There is another new format coming, and this one's a new digital
radio system called Digital Radio Mondiale to rival DAB in Europe
and IBOC and satellite radio in the US.
IBOC squeezes both analog and digital versions of the same program
into one AM or FM channel, which compromises sound quality and risks
overspill interference. IBOC has not yet been a commercial success.
You can read a devastating critique on the Internet by an independent
engineer at gullfoss2.fcc.gov.
Digital Radio Mondiale does not try to squeeze digital and analog
into the same channel. It's an either/or system; a new way to use
the existing AM bands for digital radio. DRM does not pretend to
be hi-fi. But DRM can deliver something like FM stereo quality from
AM short, medium, and long wave.
The system is a world standard and stations can switch from analog
to DRM overnight, or---as is already happening---transmit some of
the time in DRM and some of the time in analog.
So far, just as in the early days of DAB and IBOC, there have been
only a few prototype receivers, costing thousands. The big breakthrough
was the decision by RadioScape and Texas Instruments to develop
a chipset that will let one radio pull in AM analog, AM digital,
FM stereo and DAB digital. The first receivers will be unveiled
at IFA. The BBC and Radio Luxembourg will be broadcasting in DRM
for the show.
DRM is able to squeeze high quality stereo into the narrow AM bands
because it uses technology that had not been invented when DAB and
Internet audio were conceived. Here are the key facts:
Conventional AM radio uses analog modulation in channels that are
10kHz wide. The strength or amplitude of the carrier wave is continuously
varied, and the rate of change represents the frequency of the sound
signal.
For frequency modulation the frequency of the carrier wave is rapidly
varied instead of the strength. Quality is much higher but the channel
is much wider, around 200kHz.
DRM converts the original analog sound to digital code in several
steps. First the sound is filtered using a system called SBR (spectral
band replication) to separate and digitally code the top octaves
over about 7kHz, which contain mainly sibilant noise and harmonic
overtones. The lower pitch sound is separately converted into digital
code and compressed to reduce the number of bits needed by using
a system called Advanced Audio Coding. AAC works like all compression
systems to throw away sounds which the ear is unlikely to miss,
like quiet sounds masked by louder sounds of similar frequency.
But because AAC was developed more recently than the familiar MPEG/MP3
systems it works more efficiently.
The receiver uses both the AAC data and high frequency helper signal
to re-build full frequency range sound.
To help the broadcast signal resist interference, the transmitted
code is split into many parallel streams, on the principle that
if one stream does not get through most of the others will. In addition,
error correction bits added to the bitstream to let the receiver
correct digital glitches mathematically---just as a CD player can
correct corrupt bits from a dirty disc.
This technique, called Coded Orthogonal Frequency Division Multiplex,
is already used for the DVB digital TV system and for DAB.
Depending on the amount of error correction needed to protect long
range transmission, each 10kHz channel carries between 20kbps and
40 kbps. Several channels can be ganged together for faster data
rates and higher fidelity.
The DRM standard also provides for data channels, alongside the
audio. As with DAB the text can display along with the speech or
be stored for future use; or the data can deliver software updates,
for instance telling a short wave receiver how to re-tune to a better
frequency.
In March 2005 the DRM Consortium endorsed an extension of the system
allowing it to be used with frequencies up to 120MHz. This clears
the way for broadcasters to start using their existing analog FM
frequency allocations for digital broadcasting.
The biggest handicap that DRM faces is the DRM Consortium, a German-centric
group of broadcasters who are clumsily promising too much, too soon-for
instance, DRM receivers before they are ready-and thus risk giving
the new system a bad name before it has a chance to earn a good
name.
Barry Fox reports on the audio industry as columnist for the British publication Hi-Fi News. His commentary also appears in every issue of Multi Media Manufacturer.