Transcript Document

HD Distribution in the
Digital Headend
Nov 13, 2002
Marek Skupien
Scientific-Atlanta
Sr. Market Manager, Headend Systems
[email protected]
770-236-6493
HD what’s taking so long?
Consumers hesitant
to buy HD sets due to:
• High equipment cost
• Lack of programming
Few programs
available due to :
• small consumer
base with HDTV sets
…the market has been waiting to reach critical mass
Has the time arrived for HD?
• Over 2M house holds in US have an HD ready TV set
• Prices for HD sets are coming down, 2M more sets are expected to
be sold this year
• “USA’s 10 biggest operators - including AT&T Broadband, AOL
Time Warner, Comcast, Charter and Cox – said that by 2003 they
will provide a package of high-definition television” USA Today, May 2, 2002
• Numerous Headends are in process of creating “room” in their
plants for HD programs
• S-A has shipped over 100,000 HD set top boxes!!!
…yes the time is now, get ready!
DTV adoption by consumers
Digital TV Units Shipped to Dealers
14000
12000
Average Price
Based on DTV
Sales through
October 2001
Unit Shipments (000)
Normalized Prices in Dollars
16000
10000
8000
6000
4000
2000
Calendar Year
0
1998
1999
2000
2001e
2002p
2003p
Unit Shipments (000)
14
121
648
1425
2250
4000
2004p
5000
Cumm Units (000)
14
135
783
2208
4458
8458
13458
Years on Market
DTV
Color TV
Once the price point falls below $1,000 per unit (est.
Christmas ’02 or early ‘03), a strong shift towards HDTV
units is expected.
Source: DTV Guide, Jan. 02 and CEA Market Analysis, Jan. 02
Why bother with HDTV?
•Regulation
•Broadcasters need to fully convert to DTV by 2006
•Competition
•DBS is offering HD programming now
•HBO HD, Showtime HD, HD Net (NHL, Major League Baseball, etc)
•Fight for premium customer
•Cable can offer a better premium package (HD, VOD, Cable
Modem…)
•Consumers are starting to create demand
•Vendors are responding (DTV ready sets, more programming, HD
equipment)
HDTV in the Headend
Headend
Plant
LOCAL
CONTENT
Home
Explorer® 3100HD
UP TO 5 CA-QAM
BITMIZER
MULTIPLEXER
PICTOR HD RTE
DTV
BROADCAST

ATSC Demodulator
HBO, etc
OR: MQAM
IRT-2000
PBS
PowerVu IRD
C100
LOCAL SD
CONTENT
DNCS
Continuum Encoder
HDTV Set
Reception
Management
Transmission
Subscriber
DVT Program Reception
Digital Terrestrial
Broadcast is not just HD
HD reception is not just via
terrestrial digital broadcast
•May be SD or HD transmission
•May alternate between SD and HD
•Content may be locally encoded
•Content may be delivered via
based on time or program event
•Requires an ATSC demodulator
with ASI output
Satellite
•Requires a satellite decoder with
ASI output
DTV Program Reception…
…Alternating HD and SD transmission
•Some programs alternate between
one HD and several SD services
HD
SD1
SD2
SD3
SD4
How to handle the switch at the HE?
Allocate HD and
SD programs at
all time
Black screen when
program not there,
may waste b/w
Adjust program
lineup based on
time schedule
Some program are
event based and time
of switch can not be
predetermined
Let system auto
switch based on
incoming bitrates
Appears to be the
best solution, but
harder to implement
Program Management…
…Multiplexing of HD programs
HD typically uses 13 to 19.4 Mbps vs 3 to 5 Mbps for SD programs
(HD transmission in VBR may go as high as 20 or 21Mbps for short periods of time)
For Efficient use of cable plant b/w
• Multiplex 2 HD programs into 256 QAM
or
• Top of an HD program with some SD programs
Overhead
256 QAM =
38.8Mb/s
Multiple SD
or one HD
HD
19.4
19.4
Program Management…
…Transrating of HD
• transcoding, transrating, rate reducing, rate shaping
• All refer to bit rate reduction of the program
• May allow 3 or even 4 HD programs to fit through a
256QAM
• But, lower bit rate = lower quality
• Program providers generally do not want HD programs
further rate reduced at the Headend
• Need to consider subscriber reaction to lower video quality
Program Management…
…PSIP information
What is PSIP?
• Program System Information Protocol (ATSC defined)
• PSIP contains the program information
(ex. Program Name, Number, EPG, etc.)
PSIP Management:
• 3rd party PSIP management systems are available
• PSIP Management System coordinates and
consolidates PSIP information from different program
streams
Transmission …
…Bandwidth Management
•
•
HD takes a lot of bandwidth
(equivalent to 3 - 5 typical SD programs)
Many HE plants are bandwidth restrained
Solutions
1. Is there spare capacity…Optimize first!!!
2. Is it possible to move from 64 to 256 QAMs
3. Move Analog Programs to Digital
or
4. Upgrade Plant
Bandwidth Management…
…Creating Room for HD or VOD Programs
Some Cable Plants have b/w available to add HD or VOD
– Some need to make room!!!
Option 1
Upgrade plant to higher b/w
- expensive ($15 to $20 K per mile)
550
Analog
750
Digital
Aggressively convert more program
from analog to digital tier
– may need to subsidize the set top boxes
Option 2
The option that is more
cost effective is a
function of plant size,
and number of
subscribers
Ie. Subscriber Density
Conceptual models evolution of
550MHz HFC systems to HDTV carriage
50 VOD streams
500 VOD users (10:1)
Number of 6 MHz channels per Node (or Optical Rx)
0
10
20
30
40
50
60
70
80
27 Mbps (1.5 b/Hz)
675 data users (25:1)
Analog “Must Carry”
Today
Extended Analog
10
Digital Tier
40
20
50 ch
250
VOD
5
HSD
3
200 ch
channels
Analog “Must Carry”
Powell's Deal
10
262
Analog “Must Carry”
281
channels
HDTV
36
46 ch
channels
HDTV proliferation
Extended Analog
10
Extended Analog
25
35 ch
HDTV
Digital Tier
3
21
6 Ch.
216 ch
Digital Tier
13
26 Ch.
22
246 ch
VOD
HSD
5
VOD
3
HSD
5
3
Nodes can be
fragmented if more
needed
HDTV doesn’t
necessarily mean an
upgrade to 750MHz
An orderly analog to
digital transition will
enable the bandwidth at
the same time that
increases digital
penetration: the digital
tier will become the new
extended basic tier (or
likely will be
segmented)
PPV = 15% of basic
subs – replace with
VOD
Premium = 30%-40%
penetration (almost
perfect overlap with
digital footprint)
Bandwidth Management…
…Moving more programs to Digital Tier
Headend
• Encode additional programs for Digital Tier
• Need:
• Broadcast picture quality at low bit rates
• Cost effective encoders
Subscriber Implications
• With movement of more channels to digital tier, may
need to subsidize set-top boxes to provide churn of
analog subscribers
In Conclusion…
•HD is finally here due to regulation, but consumers
are latching on and it’s becoming market driven
•HD ready solutions are available
•Plant upgrades are not always necessary to add
additional content