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.

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