ATI, partners tip hybrid solution for digital TV on PC [lots of issues here]
eetimes.com
By Junko Yoshida
EE Times
(02/14/00, 1:47 p.m. EST)
SAN MATEO, Calif. — ATI Technologies Inc. has joined forces with
three other companies to demonstrate a digital TV processing solution
for PCs with an architecture that may prompt a fresh round of talks
about content protection.
Pitching "DTV on a PC" as the most cost-effective digital TV receiver
solution on the market, ATI (Thornhill, Ontario), Conexant Systems
Inc., Nxtwave Communications and Ravisent Technologies Inc. will
introduce their hardware-assisted DTV processing solution for
mainstream PCs at the Intel Developer Forum this week.
It will be offered as a PCI low-profile DTV board, both for retail and PC
OEM markets.
The design is a hybrid solution that combines the power of PC host
processing with hardware video decoding enabled by ATI's Rage 128
PRO graphics chip. The scheme has the potential to trigger a whole
new debate on PC DTV architecture among PC OEMs and add-in card
vendors.
At issue is not only how much audio/video decoding should be done in
hardware on a DTV receiver card, but also whether a pristine
HDTV-quality raw digital video stream should be allowed to cross over
a PCI bus without any protection.
Depending on the architecture, card vendors and PC OEMs will find
differences in the cost, picture quality and memory requirements of
their PC/DTVs, said chip vendors. Some pointed out that letting a
naked MPEG transport stream cross over a PCI bus to a CPU for
software demuxing and decoding could be a controversial choice.
Noting that hackers could easily tap into the PCI bus to steal the
HDTV stream, they warned that OEMs could face the threat of
lawsuits by Hollywood studios paranoid about content protection.
To date, however, Hollywood has not formally raised this as a critical
issue. Nor have Hollywood and the PC industry come to any specific
agreement on how HDTV decoding ought to be handled on a PC
platform.
"Hollywood can't stop the trend," said Gerry Kaufhold, a DTV industry
analyst at Cahners In-Stat Group. "This is an issue that studios have
to come to grips with."
In ATI's design, once DTV signals are received and demodulated on a
DTV card, a compressed MPEG-2 transport stream is sent via a PCI
bus to a CPU in a PC. Ravisent's software, running on a Pentium II
processor at 266 MHz or above, splits the transport stream into audio
and video, and decodes the Dolby Digital audio stream.
HTDV spec support
Meanwhile, most of the HDTV video decoding, including inverse
discrete cosine transformation, motion compensation and scaling, is
handled by ATI's Rage 128 PRO. The chip decodes and displays all 18
ATSC HDTV formats, said Henry Quan, vice president of strategic
marketing at ATI.
The architecture also incorporates Philips' VSB and analog tuner; a
stereo decoding chip for analog stereo; Nxtwave Communications'
VSB/QAM NXT2000 demodulation chip; and Conexant's Fusion 878A
A/D and bus-mastering chip. The card contains no DTV video
decoding ICs.
The architecture offers high picture quality at a low cost, Quan said.
He predicted that ATI's DTV card will retail at "well below $200," and
at "less than $100 for OEMs."
ATI, of course, is hardly alone in vying for the DTV/PC market.
TeraLogic Inc., a leading HDTV silicon vendor, made an early foray
into the market with its Janus decoder. The chip is capable of
decoding and displaying all 18 ATSC formats and outputting in any
common display resolution.
Unlike ATI's design, TeraLogic's chip sits right on a DTV receiver card.
Instead of a host processor, the Janus is responsible for demuxing and
video decoding. However, third-party software, such as Ravisent's
offering, will handle Dolby Digital decoding on a host CPU.
Once full HDTV video signals are decoded by the Janus chip, they are
directly displayed on a PC monitor without going through a PCI bus,
said Kishore Manghnani, vice president of marketing at TeraLogic.
In fact, under TeraLogic's Janus DTV/PC reference design, video can
be displayed either by the Janus board or by the graphics card.
In the cards
So far, PC DTV receiver card vendors such as Hauppauge Computer
Works Inc., Panasonic and Creative Labs have signed on to use
TeraLogic's chip. Those cards are expected to be on the market
"soon," said TeraLogic.
TeraLogic's Manghnani warned that any PC/DTV architecture designed
to send a raw digital bit stream over a PCI bus could only prompt
Hollywood to take issue with the PC industry on the potential threat
for copy protection. "Under our PC/DTV design, Panasonic, for
example, could choose to disable the transport stream to be sent over
the PCI bus," said Manghnani. Already burned on the hacking of
DVD-Video's content-scrambling system, the Motion Picture
Association of America is said to be extremely wary of the potential of
illegal copying on a PC.
Descrambling broadcast signals is another important issue for PC
OEMs, Manghnani said. "Service providers are considering all kinds of
scrambling methods, including applying triple DES [Data Encryption
Standard] in order to protect their content," he said. "Something as
strong as triple DES cannot be descrambled by a CPU in a PC." |
