White Paper on Digital Media Technology

White Paper on Digital Media Technology
Crestron DigitalMedia™ Design Guide
© 2009
Crestron Electronics, Inc.
15 Volvo Drive
Rockleigh, NJ 07647
800.237.2041
www.crestron.com
HDMI™ and High Definition Multimedia Interface are trademarks of HDMI Licensing, LLC in the United States and other countries.
All brand names, product names and trademarks are the property of their respective owners.
Crestron DigitalMedia™ Design Guide
CONTENTS
What is HDMI? ................................................................................................................................................................... 1 Advantages of HDMI versus Analog Interfaces ................................................................................................................ 1 It’s Not Just Cable Length............................................................................................................................................... 1 Say Goodbye to Analog ................................................................................................................................................... 2 Comparing the Cables .................................................................................................................................................... 3 Topology ........................................................................................................................................................................ 4 EDID ............................................................................................................................................................................... 4 Consumer Electronics Control (CEC)................................................................................................................................ 6 Audio.............................................................................................................................................................................. 7 Convergence .................................................................................................................................................................. 7 What About DisplayPort? ............................................................................................................................................. 7 Section Conclusion ......................................................................................................................................................... 8 Crestron DigitalMedia ....................................................................................................................................................... 9 Features of DigitalMedia ................................................................................................................................................. 9 Application Diagrams ...................................................................................................................................................... 10 Residential Multi-Room Distribution .............................................................................................................................. 10 Dual Projector Classroom Application ........................................................................................................................... 11 Small Classroom .......................................................................................................................................................... 12 Network Operations Center Scenario ............................................................................................................................ 13 Design and Install a DigitalMedia System...................................................................................................................... 14 Step 1: Select the Wiring for Each Run ......................................................................................................................... 14 DigitalMedia Cable .................................................................................................................................................... 16 CresCAT®-D .............................................................................................................................................................. 16 Fiber Optics............................................................................................................................................................... 16 CresFiber™ .............................................................................................................................................................. 18 Selecting Third Party Fiber (advanced) ...................................................................................................................... 18 Selecting the Optical Fiber ........................................................................................................................................ 18 Selecting the Jacket Configuration ............................................................................................................................ 19 Wiring Connection ..................................................................................................................................................... 20 Step 2: Select DigitalMedia Equipment ......................................................................................................................... 21 Switcher Chassis....................................................................................................................................................... 21 DigitalMedia Switcher Input Cards - Local Sources.................................................................................................... 21 DigitalMedia Switcher Input Cards - Remote Sources ................................................................................................ 22 DigitalMedia Switcher Output Cards .......................................................................................................................... 23 DM-MD6X1 Transmitter ............................................................................................................................................ 24 DigitalMedia Room Solution Boxes ............................................................................................................................ 26 Step 3: Prewiring ......................................................................................................................................................... 27 HDCP Wiring Notes.................................................................................................................................................... 27 Copper ...................................................................................................................................................................... 27 Fiber ......................................................................................................................................................................... 27 Step 4: System Commissioning .................................................................................................................................... 27 DM-MD8X8 Features ....................................................................................................................................................... 28 DigitalMedia Device Quantity Limits .............................................................................................................................. 28 DM Transmitters .............................................................................................................................................................. 29 For Sources Located Away From the Switcher ........................................................................................................... 29 DigitalMedia Repeater DM-DR ........................................................................................................................................ 30 Appendix A - The Device List .......................................................................................................................................... 31 HDCP Limits in Source Devices..................................................................................................................................... 31 DigitalMedia Source Testing ......................................................................................................................................... 31 Device List ................................................................................................................................................................... 32 Check website (www.crestron.com) for product availability
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Crestron DigitalMedia™ Design Guide
Glossary ........................................................................................................................................................................... 33 Video Resolution Terminology ....................................................................................................................................... 33 Video Display Terminology............................................................................................................................................ 34 Encoding Terminology .................................................................................................................................................. 36 ii
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Crestron DigitalMedia™ Design Guide
What is HDMI?
High Definition Multimedia Interface (HDMI)
is the first and only consumer electronics
industry-supported, uncompressed, all digital
audio/video interface. By delivering crystal
clear, all digital audio and video via a single
cable, HDMI dramatically simplifies cabling
and provides consumers with the highest
quality AV experience.
Advantages of HDMI versus Analog Interfaces
HD content ready: Consumers using HDMI devices supporting HDCP have the comfort of knowing that they will have access
to premium HD content now and in the future. Content providers (a.k.a. movie studios and television networks) are requiring
that devices transmit HD video only to “protected outputs” that use HDCP. With today’s HD movies, content can be sent over
unprotected interfaces—such as analog component—because Blu-ray has delayed the activation of the image constraint
token (a.k.a. content protection flag) to help minimize potential transition issues. This activation is expected in a few years,
meaning future HD movies will no longer be viewable at HD resolutions over analog component and other unprotected
interfaces. A similar situation exists with cable and satellite TV, in which the Motion Picture Association of America (MPAA)
is petitioning the FCC to restrict HD transmission to protected outputs.
Quality: Because HDMI is a digital interface, it has lossless transmission and provides the best video quality, unlike analog
video. The difference is especially noticeable in low brightness scenes and at higher resolutions, such as 1080p. Digital video
is sharper than component, and eliminates the softness and ghosting found with component. Small high contrast details, such
as text, especially bring out this difference.
Ease of use: HDMI combines video and multi-channel audio in a single cable, eliminating the cost, complexity, and confusion
of multiple cables currently used in AV systems. This is particularly beneficial when equipment is upgraded or added.
Intelligence: HDMI supports two-way communication between the video source (such as a DVD player) and the DTV, enabling
new functionality such as automatic configuration. By using HDMI, devices automatically deliver the most effective formats
(e.g., 480p vs. 720p, 16:9 vs. 4:3) for the displays to which it is connected, eliminating the need for external intervention
to identify the best resolutions and audio formats.
It’s Not Just Cable Length
The promise of HDMI is great. One cable carrying uncompressed digital HD video and audio; what’s not to like? But mention
HDMI to an AV integrator and you’re likely to get an expletive in response. A quick search of online forums and industry trade
publications uncovers a slew of HDMI related complaints, ranging from annoying switching delays and screen flashing to
complete audio and video failure.
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Crestron DigitalMedia™ Design Guide
There are two primary reasons for HDMI problems: bandwidth and complexity. Uncompressed HD video requires enormous
digital bandwidth, which is notoriously difficult to push through copper wire. Add popular features such as 1080p resolution
and the potential offered by Deep Color and the problem worsens.
There are a number of products appearing on the market that attempt to address this issue, some of which actually work
quite well. But the under-discussed issue is the sheer complexity of HDMI.
HDMI is a full-duplex digital communications interface. The creators of HDMI took advantage of its digital nature, and added
several communications mechanisms to automatically control and encrypt content. Unfortunately, the custom installation
industry wasn’t considered in the design process, and HDMI doesn’t scale well. Compounding the problem is the fact that
digital control is relatively new to most of the major AV distribution players, so the learning curve has been very steep.
Though much more complex than analog, HDMI isn’t nearly as complicated as home automation, Ethernet, or any of the
myriad wireless protocols. Companies with experience in these fields are in a position to implement HDMI in environments
that the designers hadn’t anticipated.
This portion of the guide will address the need for the move to HDMI and explain the new features that HDMI supports. We’ll
demystify the “handshaking” that occurs between HDMI sources, repeaters, and displays, and explore the cause of some
common problems experienced in the field.
Say Goodbye to Analog
Before we get too involved in the technical details, there’s an important question to address: why do we need HDMI? Although
analog video distribution works very well for much of the market, analog is on its way out. Content providers such as television
and movie studios love the fact that HDMI supports the High-bandwidth Digital Content Protection (HDCP) protocol. HDCP
allows them to encrypt content while it’s on the wire, so it can’t easily be copied and pirated. They’re pushing hard on the
consumer electronics industry to move from analog to HDMI, and they’re making progress. For the unconvinced, here are
a few harbingers of analog’s demise:
Image Constraint Token: The Blu-ray specification has a built-in time bomb that’s yet to go off; the Image Constraint Token
(ICT). This embedded flag forces players to downgrade video on analog outputs to standard definition, which is one quarter
the resolution of the current analog maximum, 1080i. The movie studios are waiting for more widespread HDMI and Blu-ray
adoption before shipping discs that implement this limitation, and have reportedly decided not to do so until 2010 or 2012.
Content provider support: SkyHD, a popular European satellite service, is already shipping HDMI-only set top boxes. And
here in the United States, the Motion Picture Association of America (MPAA) is petitioning the FCC for permission to block
movies from being transmitted on set top box analog outputs.
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Crestron DigitalMedia™ Design Guide
Feature support: The latest and greatest features are only supported by HDMI. The aforementioned 1080p and Deep Color
formats, for instance, aren’t, and will never be, available over analog. The more discerning consumers, who are the bread
and butter for much of the custom installation industry, expect these sophisticated features.
Any analog distribution system that carries commercially created content runs the risk of becoming obsolete over the next
several years. Now is the time for the consumer electronics and custom installation industries to embrace the transition.
Comparing the Cables
Analog Cables






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

HDMI Cable









Separate audio and video cables
Robust signals
Field termination
Inexpensive
Installer friendly
Reliable multi-room distribution
Distance is rarely an issue
Secure cables
No copy protection (DRM) support
Single AV cable
Delicate signals
Cannot be field-terminated
Very expensive
Difficult to run
No reliable multi-room solution
Limited distance
Non-locking cable
Supports copy protection
The complexity of HDMI becomes obvious when you compare HDMI cable to analog audio and video cables. Analog cables
typically consist of one to three wire pairs, depending on the format, and they simply carry an audio or video signal (not both).
In contrast, the HDMI cable consists of 19 wires, which carry high speed video, audio and other digital information. The digital
audio and video data is encoded into three color channels and a clock channel. Audio is embedded inside the video data and is
inserted and extracted at each end. Additional information carried by HDMI includes:
DDC: The Data Display Channel (DDC) is a two-way communications interface between the source and the downstream
repeater or display device. This channel was originally provided to communicate device capability information, which is
encoded in a structure known as Extended Display Identification Data (EDID). HDMI devices use EDID to indicate what audio
and video formats they support, discussed in more detail in a later section. The DDC interface is also used to set up and
maintain HDCP encryption.
Hot Plug Detect: The downstream device, or sink, indicates its presence to the source with the Hot Plug Detect (HPD)
signal. This allows each device to know when a cable has been connected and to start authentication.
CEC: Consumer Electronics Control (CEC) channel wiring is mandatory, although implementation of CEC in a product is
optional. The CEC channel uses the industry standard AV Link protocol for remote control functions, and is a one wire
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Crestron DigitalMedia™ Design Guide
bidirectional serial bus. The CEC feature allows the user to command and control multiple CEC-enabled boxes with one
remote control, and individual CEC-enabled boxes to command and control each other without user intervention.
Depending on the device and manufacturer, DDC, HPD, and CEC signals interact differently. This inconsistency can
negatively affect device performance.
Additional control signals are associated with HDMI, but they are beyond the scope of this guide.
Topology
Every HDMI installation consists of at least one content source, like a cable box or Blu-ray player, and a sink, like a TV or a
projector. Most custom installations also involve at least one repeater, which is a device that accepts and re-transmits HDMI
content. Repeaters include simple devices such as switches and distribution amplifiers as well as more feature-rich devices
like audio and video processors.
EDID
EDID is the information transmitted from a display to a source conveying its resolution capabilities. Initially developed for
computers and monitors, EDID has made its way into consumer electronic devices via HDMI. HDMI displays and surround
sound receivers use EDID to communicate their audio and video capabilities. For instance, a television may use EDID
to indicate support for the standard HD resolutions plus 1080p and Deep Color. Another TV may not accept higher than
720p/1080i resolution. One audio processor may support Dolby TrueHD while another only supports standard Dolby;
most TVs only support basic stereo audio. All of this information is stored in EDID.
The content source reads and analyzes EDID to determine what formats to send. It is the responsibility of the source, if
equipped, to only send formats that the downstream devices support. For example, Blu-ray players include video scalers to
best match the disc’s native format to the capabilities of the television or projector.
In the simplest installations, with one television and an audio processor, the EDID protocol works reasonably well. Multiroom installations, on the other hand, can quickly become problematic, with several televisions connected to several sources
through one or more HDMI switches. The switches are responsible for collecting all of the televisions’ EDID and providing one
unified version to the source. Neither the HDMI nor the EDID specifications offer guidance in this scenario. As a consequence,
different switches behave in different ways. Combining multiple EDID can be a complicated issue, so it's worth researching
how a given switch handles it prior to installation.
Consider a simple system. The client has a 1080p projector with a surround sound processor in the home theater, and a 720p
LCD with integrated speakers in the family room. The 1080p projector also supports 720p, but obviously the customer would
prefer 1080p where possible. How should the switch combine the EDID? Some devices on the market simply copy the EDID
from the first output. In our scenario, 1080p video and surround sound audio is sent to the family room, which supports
neither. At best, this results in no audio and no video and at worst, damage to the LCD display or speakers. A slightly smarter
switch may take a “best common” approach, generating merged EDID that limits the content to only what both rooms can
support; 720p video and stereo audio. Now, the client’s sophisticated home theater can no longer achieve exceptional content
quality. Extrapolate this scenario to the installation with five or ten rooms and this simple solution becomes inadequate.
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Crestron DigitalMedia™ Design Guide
Crestron DigitalMedia is an intelligent system that allows installers to make design decisions that set the fewest limits (if any)
on content quality across multiple displays. For example, let’s say the client only watches Blu-ray content in the home theater,
but watches cable TV in both the home theater and the family room. With the proper switch, the installer can configure input
EDID independently, so that the Blu-ray player can send the full 1080p and surround sound signal to the home theater, while
the cable box, which must support both rooms, is limited to 720p or 1080i. This isn't much of a sacrifice, since cable
companies don’t actually transmit 1080p content anyway (though some cable boxes will up-convert to 1080p). A really nice
switch accepts surround sound for the home theater, and down-mixes it to basic stereo for the family room.
HDCP
HDCP encryption is another complicating factor in HDMI installations. The HDCP system has two parts:
1.
2.
it authenticates HDCP devices to make sure they are authorized to receive the content, and
encrypts the content to prevent interception during transmission.
Authentication ensures that all devices receiving the content are licensed and authorized. Only after successful authentication
can the display output the audio and video streams.
HDCP Encrypts Each Individual Segment of an AV Transmission
HDCP Authenticates Each Device via the Source
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Crestron DigitalMedia™ Design Guide
Devices that re-transmit HDCP content must inform the source of all the downstream connections in the system. Every HDCP
device has a unique ID, known as a KSV (Key Selection Vector), which must be passed to the source. The source must then
verify each device before it transmits content. It is this authentication process that causes the 5-10 second switch times
in HDMI devices. DigitalMedia solves this “blank screen” issue by using a technology called QuickSwitch HD™. In a standard
HDMI switcher, each display is authenticated dynamically when video is routed to it. With DigitalMedia, the authentication
process takes place as displays are added. During initialization, sources are authenticated with each display through the
DigitalMedia system before any audio or video is routed. By doing this, each switch can occur instantly.
Unfortunately, all sources have a hard limit on the number of displays that can be connected, due to a limit in the number
of KSVs they will accept. The HDCP specification allows for up to 127 devices, but sources usually support far fewer. Many
support fewer than ten devices, and for at least one popular cable box in the field, it’s only one. If a repeater presents a source
with too many KSVs, the source stops transmitting content. Unfortunately, KSV limits are not an advertised feature. Clients
won’t even realize they have a problem until they try to route a given source an extra repeater or display. Audio and video
drops out inexplicably in all connected rooms, typically without so much as an error message.
Again, a solution is needed that allows installers to make intelligent design decisions. During commissioning, the DigitalMedia
system tests the KSV limits of each source, and sets appropriate limits on the switch. It will bring any problem areas to the
attention of the installer, to be solved before becoming end user issues.
Installers must be aware of KSV limit issues in any HDMI installation that involves more than one display. Be sure to research
how your equipment handles scenarios that violate source KSV limits using the device list (page 31) and by testing devices
in the field.
Consumer Electronics Control (CEC)
Each HDMI cable contains a communication link that enables devices connected via HDMI to talk to each other. This protocol
is called Consumer Electronics Control (CEC). When a control system is in place, however, you don’t want other devices
issuing commands. CEC is supposed to contain industry standard commands for interoperability, but inconsistent support
from CE manufacturers has caused a wide variation in the functions that can actually be triggered from each device. Some
examples of this functionality that Crestron has discovered are:


Multiple DVD players from the same manufacturer, in the same system, communicate with each other so that only
one can play at a time. Every time one player is issued the play command, the player sends a pause command to
the other players over CEC
When a Blu-ray player is turned off, it sends a power off command, turning off all the displays connected to
the system.
These functional commands are a major issue, because they are sent behind the scenes and without your knowledge.
DigitalMedia breaks the communication path between the HDMI devices that are connected to the switch, so these commands
cannot be sent without your approval. In addition, DigitalMedia provides a method to issue CEC commands from a control
system, so the communication link can be used for your benefit, as an alternative to IR and RS-232 control.
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Crestron DigitalMedia™ Design Guide
Audio
HDMI provides the only transmission link for 7.1 channel HD audio. However, unlike traditional analog video sources, HDMI
sources usually do not transmit multi-channel and 2-channel audio at the same time. This becomes a problem for multi-room
distribution, in which a mixture of surround sound and stereo audio rooms are present. HDMI sources will often shut off analog
outputs when sending audio over HDMI.
Audio Distribution
Crestron solves this problem by offering special HDMI cards that will take in a multi-channel audio stream and output both
types of audio for distribution. These special cards are noted by a –DSP suffix.
Convergence
HDMI enables computers to deliver premium media content, including high definition movies and multi-channel audio formats.
HDMI is the only interface enabling connections to both HDTVs and digital computer monitors implementing the DVI and HDMI
standards, which amounts to hundreds of millions of DVI displays in use today.
HDMI is fully compatible with all DVI-enabled computers, because HDMI was developed using the same technology as DVI
(Digital Visual Interface), which has been the most common digital connection for computers. However, since HDMI offers both
audio and video over one cable and DVI carried only video, DVI/HDMI connectivity requires a separate audio cable.
HDMI enables computers to deliver premium media content, including high-definition movies and multi-channel audio
formats. It is the only interface enabling direct connections to both HDTVs and digital computer monitors implementing the DVI
and HDMI standards, which amounts to hundreds of millions of existing DVI displays.
What About DisplayPort?
DisplayPort is a new VESA standard for digital video connection, similar to HDMI in functionality. While HDMI was introduced in
2001, the latest DisplayPort specification (1.1a) was released in 2008, which has given HDMI devices a huge head start in
device adoption. The DisplayPort standard was driven by the PC industry, to achieve a low cost process for transferring video
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Crestron DigitalMedia™ Design Guide
from a computer to a laptop screen and external digital video output. Both protocols support 1080p and higher resolutions,
HDCP content protection, multi-channel audio and Deep Color. HDMI additionally supports some items that DisplayPort does
not, such as CEC control and Dolby/DTS 8-channel audio streams.
VESA realized that they were late to the digital video game with DisplayPort, and it didn’t make sense to have a video output
that could not plug into 95% of the displays in the world today. They added backwards compatibility to HDMI and DVI (and
sometimes RGBHV -- but that doesn’t include content protection). This means that an HDMI input can accept video from DVI,
HDMI and DisplayPort devices -- making it the most universal connector going forward. Summary
Wide support from content providers and the consumer electronics marketplace makes HDMI the future of HD video
transmission. This brings many pitfalls to the uninformed installer (especially in larger installations) and the problems are
not limited to cable length issues. Processing EDID and managing HDCP requires complex microcontrollers, especially
when several rooms are involved. Switching systems must be easily customizable to intelligently handle HDCP and EDID.
DigitalMedia manages these various communication mechanisms and provides extensive troubleshooting information,
so the installer can solve issues like cable failure, device incompatibilities and content protection complications.
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Crestron DigitalMedia™ Design Guide
Crestron DigitalMedia
Crestron DigitalMedia distributes uncompressed digital audio and video signals over a choice of CAT5e/6-based copper wiring
or duplex multimode fiber cable. A full selection of switcher input cards, wall plate transmitters, and room solution boxes
provide extensive connectivity throughout the installation, supporting a complete range of analog and digital signal types.
DigitalMedia intelligently manages all the different signals and devices, matching each source's output to the capabilities of
the selected display(s) without scaling or compression. Every signal is preserved in its native video resolution and audio
format, ensuring a pure, lossless signal path.
DigitalMedia handles more than just audio and video. Integrated Gigabit Ethernet, device control (IR, RS-232) and USB mouse
and keyboard distribution allows computers, media servers, and video game consoles to be installed out of sight and accessed
from anywhere in the installation. With no additional wiring, built-in Crestron control is also available for controlling displays
and other room devices.
DigitalMedia:
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

Distributes uncompressed digital audio and video over CAT5e/6 or fiber
Supports HDMI 1.3a with Deep Color and 7.1 channel HD lossless audio
Supports video resolutions up to 1920x1200 or 1080p/60
Allows full 1080p/60 up to 400 feet using CAT5e or CAT6 cable
Supports 50/125 and 62.5/125 multimode fiber for distances up to 1km (3280 ft).
Features of DigitalMedia
DigitalMedia transmits a wide variety of signals:
Audio
Video
Other
HDMI 7.1 Channel
2.0 PCM
DTS-HD
Dolby TrueHD
SPDIF
2-Channel Analog
DisplayPort
HDMI
Component (Y/Pr/Pb)
S-video
Composite
RGBHV
DisplayPort
HD-SDI
DVI
Ethernet
DMNet™
Crestron Control
USB HID
DigitalMedia is installer-friendly, with a flexible choice of input and output cards. It expands easily to serve the most demanding
multi-room solution. Advanced troubleshooting tools can be accessed via the front panel, toolbox, and control system to
identify potential problems with HDCP keys and handshaking, CEC control, video resolutions, USB, and audio format issues.
DigitalMedia accommodates legacy AC systems, provides a zero-latency solution, and drives full HD content without
compression or resolution loss.
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Crestron DigitalMedia™ Design Guide
Application Diagrams
Residential Multi-Room Distribution
NOTE: Refer to www.crestron.com/digitalmedia for sample schematic and bill of materials.
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Crestron DigitalMedia™ Design Guide
Dual Projector Classroom Application
NOTE: Refer to www.crestron.com/digitalmedia for sample schematic and bill of materials.
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Crestron DigitalMedia™ Design Guide
Small Classroom
NOTE: Refer to www.crestron.com/digitalmedia for sample schematic and bill of materials.
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Crestron DigitalMedia™ Design Guide
Network Operations Center Scenario
NOTE: Refer to www.crestron.com/digitalmedia for sample schematic and bill of materials.
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Crestron DigitalMedia™ Design Guide
Design and Install a DigitalMedia System
Step 1: Select the Wiring for Each Run
DigitalMedia supports the following wiring options:
1. DigitalMedia Cable
2. CresCAT®-D cable
3. CresFiber™ (Crestron multimode fiber)
4. Third party multimode fiber
Cross-Section Comparison of Cables
DM-DR – DigitalMedia Repeater
One cable run of DigitalMedia Cable or CresCAT-D is required
for each DigitalMedia room solution box connection.
The choice of wiring for your installation is usually dictated by
the cable lengths required.
The copper DigitalMedia solutions (DigitalMedia Cable and
CresCAT-D) support repeaters (DM-DR) to extend their transmission
distance. Refer to Step 4, pre-wiring on page 27.
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Crestron DigitalMedia™ Design Guide
DigitalMedia Signals
D Port
M Port
PIN
SIGNAL
DESCRIPTION
1
DATA D0+
HDMI Blue
2
DATA D0-
HDMI Blue
4
DATA D1+
HDMI Green
5
DATA D1-
HDMI Green
7
DATA D2+
HDMI Red
8
DATA D2-
HDMI Red
3
CLK-
HDMI Clock
6
CLK +
HDMI Clock
DMNet
PIN
SIGNAL
DESCRIPTION
1
+5V
+5V Power
PIN
2
I2C_DATA
HDCP & EDID Data
3
E_TX-
10/100BaseT Transmit
6
E_TX+
10/100BaseT Transmit
4
E_RX-
10/100BaseT Receive
5
E_RX+
10/100BaseT Receive
7
I2C_CLK
HDCP & EDID Clock
8
+5V_RTN
+5 Power Return
SIGNAL
DESCRIPTION
24
+24v
DC Power
A
DM_NET+
DMNet
B
DM_NET-
DMNet
G
GND
DC Ground
The transmission distances between repeaters are determined by the video resolution sent over the wires. The total distance
that video can be sent using repeaters is also shown in Table A for each cable type. Up to three repeaters may be used to
extend the transmission distance, as shown in Diagram A.
Table A
Resolution
1080i / 720p / 1080p 24Hz
1024x768 75Hz
1280x1024 75Hz
1600x1200 60Hz
1920x1200 60Hz
1080p 60Hz
1080p 60Hz Deep Color
CresCAT-D
H
T
(Distance between
(Total distance using
repeaters)
up to three
repeaters)
45m (150 ft)
45m (150 ft)
30m (100 ft)
120m (400 ft)
23m (75 ft)
30m (100 ft)
30m (100 ft)
NOT SUPPORTED
DigitalMedia Cable
H
T
(Distance between
(Total distance
repeaters)
using up to three
repeaters)
60m (200 ft)
60m (200 ft)
45m (150 ft)
137m (450 ft)
38m (125 ft)
45m (150 ft)
45m (150 ft)
30m (100 ft)
120m (400 ft)
Diagram A
Key:
H = Distance between
repeaters
T = Total distance using up
to three repeaters
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Crestron DigitalMedia™ Design Guide
DigitalMedia Cable
This cable is specially engineered for DigitalMedia by Crestron. Up to two patch panels may be used on any DigitalMedia
Cable run, but they must use shielded connectors rated for CAT6a.
Because the “D” video cable is shielded, it must be terminated using RJ45 connectors provided by Crestron (DM-CONN-20).
These connectors can be terminated without any specials tools; all that is needed is a wire cutter. Refer to Data Sheet
Doc. 6767A for additional termination details. DigitalMedia Cable is available in two versions, plenum and non-plenum:


DM-CBL-NP-SP500
DigitalMedia Cable - (1) High bandwidth/low crosstalk shielded 4-twisted-pair,
(1) CAT5e, and (1) DMNet control cable; non-plenum, 500 ft spool
DM-CBL-P-SP500
DigitalMedia Cable - (1) High bandwidth/low crosstalk shielded 4-twisted-pair,
(1) CAT5e, and (1) DMNet control cable; plenum-rated, 500 ft spool.
CresCAT®-D
Standard CAT5e provides less distance than DigitalMedia Cable, but can be terminated using standard RJ45 connectors.
Note that these signals are more susceptible to interference, because they are transmitted in unshielded cables. Care should
be taken to ensure that they are not run alongside interference-causing sources. Up to two patch panels may be used on any
CresCAT-D cable run.

CresCAT-D-NP-SP500
(2) CAT5e plus Cresnet® (or DMNet™) control cable, non-plenum, supplied in a 500 ft spool
NOTE: If using third party CAT5 wiring, do NOT use low-skew CAT5 for the “D” cable.
Fiber Optics
Fiber transmission distances are not affected by video resolution, so only a single number for total distance is shown in Table
B. Unlike copper solutions, no repeaters are used (Diagram B).
Diagram B
Key: T = Maximum total distance between DigitalMedia devices
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Crestron DigitalMedia™ Design Guide
For the fiber DigitalMedia solutions, if your application only calls for runs up to 300m (1000 ft) then you can use the standard
fiber receiver products (DMC-F, DM-RMC-100-F). If you need to go further than 300m, use the long distance fiber receiver
products (DMC-F-LD, DM-RMC-100-F-LD) that will allow you to send DigitalMedia up to 1km. DigitalMedia fiber optic
components use two standard SC multimode connectors for each signal. Crestron recommends the Corning® infiniCor®
Pretium™ termination system for installing the connectors.
Table B - Fiber
Resolution
Standard Receivers
Long Distance Receivers
T (Total Distance)
T (Total Distance)
300m
(1000 ft)
1000m
(3280 ft)
1080i / 720p / 1080p 24Hz
1024x768 75Hz
1280x1024 75Hz
1600x1200 60Hz
1920x1200 60Hz
1080p 60Hz
1080p 60Hz Deep Color
All resolutions up to and including Deep Color can be transmitted the same distance.
1080p/60Hz is the most common resolution used in residential installations.
Due to limited support, Deep Color is not often used.
About Deep Color
Deep Color is an option that was added to HDMI 1.3. It allows devices to transmit video using 36 bits per pixel instead of 24
bits per pixel. This new color depth allows for 4096 shades each of red, green and blue instead of only 256. It is a good
concept, but in reality it is unlikely to be available anytime soon. Cable and satellite companies do not have the bandwidth to
support transmission of that size. Some Blu-ray players “support” Deep Color, but the Blu-ray standard does not. This
means that the content itself is only 24-bit and the player just dithers the colors, providing no real increase in video quality.
Given the lack of support for this feature and the decrease in transmission distances that it entails, Crestron recommends
using standard 1080p unless Deep Color is specifically requested.
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17
Crestron DigitalMedia™ Design Guide
CresFiber™
Crestron makes available a multimode fiber solution for DigitalMedia called CresFiber. It contains four strands of
50 micron multimode fiber for long distance transmission inside a single indoor/outdoor rated jacket. Two strands
are used for DigitalMedia and the other two strands are available for redundancy and expansion.
DigitalMedia fibers use high performance OM3 cores with an EMB rating of over 1000MHz-km at 850nm
to achieve long transmission distances.
Standard CresFiber is easy to run and terminate for cable runs that are 300m (1000 ft) or less, and it is highly recommended
for these applications. Standard CresFiber contains four fiber strands in a “breakout” cable formation; each strand has its own
3mm jacket with strength members inside. This gives it the ability to be terminated directly to the DigitalMedia equipment,
because each strand can support a large amount of tension. CRESFIBER-PRO is designed for longer cable runs (over 300m /
1000 ft), so it has a much smaller diameter and comes in larger spool lengths. CRESFIBER-PRO is built in a “distribution”
cable formation, where the strength member is part of the overall jacket, not the individual cables. It is recommended that a
breakout or similar kit be used to attach the strength members to the fiber strands.


CRESFIBER-NP-SP1000 - CresFiber fiber optic breakout cable: (4)50/125 multimode fiber strands.
Plenum-rated version available. Available in 300m (1000 ft) spools
CRESFIBER-PRO-NP-SP1KM – CRESFIBER-PRO fiber optic distribution cable: (4)50/125 multimode
fiber strands with 900u tight buffers. Plenum-rated version available. Available in 1km (3280 ft) spools.
Selecting Third Party Fiber (advanced)
Picking the correct fiber cabling for your application is a function of distance and the physical location of the cable. The optical
fiber (the part that carries the optical signal) determines the distance, and the jacket configuration depends on the application
(i.e. plenum, outdoor rating, number of fibers, etc). Either 50u or 62.5u multimode fiber may be used so long as the bandwidth
of the fiber is sufficient (see next section).
Selecting the Optical Fiber
Your selection of fiber cabling must have enough bandwidth to carry the DigitalMedia signals. The bandwidth of multimode
fiber is inversely proportional to the length of the fiber, because of the way multimode fiber works. The bandwidth of the fiber
is measured in Effective Modal Bandwidth (EMB), or MHz*km. For example, a 500MHz*km fiber can carry a 500MHz signal
1km, or a 250MHz signal 2km. Each fiber cable also has a different EMB rating at the two commonly used multimode
wavelengths, 850nm and 1300nm.
NOTE: The bandwidth of fiber cables are calculated based on several different standards put out by the TIA/EIA. This is
because the bandwidths vary slightly, depending on whether the light source is a laser or LED. DigitalMedia is a laser-based
fiber system, so the laser bandwidth should be used. This is sometimes referred to as RML BW (restricted mode launch
bandwidth) or EMBc (Effective Modal Bandwidth calculated).
The calculations must be done at both wavelengths to ensure there is enough bandwidth for each. The DigitalMedia
application requires the following bandwidth over fiber:
1200MHz @ 850nm
150MHz @ 1300nm
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Crestron DigitalMedia™ Design Guide
To calculate the distance that a DigitalMedia fiber transmission can be run, divide the bandwidth rating of the fiber by the
DigitalMedia bandwidth.
Example:
Corning® infiniCor600® has the following bandwidth ratings: 500MHz*km @ 850nm and 500MHz*km @ 1300nm. How far can
you send DigitalMedia over that fiber?
850nm: 500MHz*km / 1200MHz = 416m (1365 ft)
1300nm: 500MHz*km / 150MHz = 3.3km (10,826 ft)
This fiber is able to drive DigitalMedia up to 416m (1365 ft). If you know the distance and need to determine which fiber
will work, you can also multiply the DigitalMedia bandwidth by the distance to find the minimum fiber bandwidth.
Example:
I need to send DigitalMedia over fiber 300m. What is the bandwidth requirement for my fiber cable?
850nm: 1200MHz * 300m = 360MHz*km
1300nm: 150MHz * 300m = 45MHz*km
Corning infiniCor600 supports 500MHz*km at both wavelengths, therefore it is an acceptable fiber type for this installation.
Selecting the Jacket Configuration
When using fiber, it is recommended that you have at least two spare fibers for each location; a minimum of four strands in
your fiber jacket should be run to each endpoint. Ensure that your fiber cable has the correct ratings for your installation (i.e.
plenum, outdoor, UL, etc). Crestron recommends using a breakout type cable system for basic installations, because the fibers
can be directly terminated to the DigitalMedia equipment.
Check website (www.crestron.com) for product availability
19
Crestron DigitalMedia™ Design Guide
Wiring Connection
Diagram C
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Crestron DigitalMedia™ Design Guide
Step 2: Select DigitalMedia Equipment
Switcher Chassis
There are two DigitalMedia switcher card frames available, 8X8 and 16X16.
Each switcher permits inputs to be cascaded up to four additional switchers, increasing the number of available outputs in the
system. For example, using five DM-MD16X16 switchers in a system permits a total of 80 available outputs.


The DM-MD8X8 ships without cards; you must order both input and output cards
The DM-MD16X16 is pre-loaded with output cards in several popular configurations, but you must order input cards
separately. Check the Crestron website for available models.
Select Input Cards
Each switcher accommodates a card for individual video input.
DigitalMedia Switcher Input Cards - Local Sources
All input cards provide an HDMI loop output for switcher expansion.
DMC-HD
Includes HDMI 1.3a input, RCA analog audio output (which
breaks out the embedded HDMI audio to feed a multi-room
audio distribution system), and USB HID port (passes
a remote mouse/keyboard signal to the source device,
i.e. computer, game console, etc.).
DMC-HD-DSP
Same features as the DMC-HD plus internal DSP
processing to simultaneously provide both uncompressed
7.1 channel HD surround sound and 2-channel audio
for distribution via the RCA analog audio output and
DigitalMedia.
DMC-VID-RCA-D
Includes multi-format RCA inputs supporting component,
S-video, and composite video signals. Also includes SPDIF
digital audio input.
DMC-VID-RCA-A
Includes multi-format RCA inputs supporting component,
S-video, and composite video signals. Also includes RCA
analog audio input.
DMC-VID-BNC
Includes multi-format BNC inputs supporting component,
S-video, composite video signals, and balanced or
unbalanced stereo audio.
DMC-VID4
Includes four RCA composite video inputs w/built-in
sequential switcher and quad processor. Supports
dynamic colored text overlay on all four video windows
for easy identification.
Includes DVI-I input with breakout cable supporting DVI,
RGBHV, component, S-video, and composite video signals.
Also includes balanced or unbalanced stereo audio input
and USB HID port.
DMC-DVI
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Crestron DigitalMedia™ Design Guide
DigitalMedia Switcher Input Cards - Remote Sources
DMC-CAT
Receives a DigitalMedia signal from a DigitalMedia
transmitter via CAT5e/6 or DigitalMedia Cable. Includes
DigitalMedia input ports, and RCA analog audio output
to break out audio embedded in the DigitalMedia signal.
DMC-CAT-DSP
Similar to DMC-CAT with internal DSP processing to enable
simultaneous 7.1 and 2-channel audio output.
DMC-F and
DMC-F-LD
Receives a DM signal from a DM transmitter via multimode
optical fiber cable. Includes DigitalMedia fiber input and RCA
analog audio output.
DMC-F-DSP and
DMC-F-DSP-LD
Similar to DMC-F with internal DSP processing to enable
simultaneous 7.1 and 2-channel audio output.
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Crestron DigitalMedia™ Design Guide
Select Output Cards
You must also select the output cards for the DM-MD8X8 switcher chassis from the following available cards:
DigitalMedia Switcher Output Cards
DMC-CATO-HD
DMC-CATO
Provides four DM outputs to feed up to four individual DM
receivers via twisted pair cable. HDMI outputs on DM outputs 1
and 3 feed local devices. Each HDMI output is active
simultaneously with the corresponding DM output to drive two
separate devices.
Provides four DM outputs to feed up to four individual
DM receivers via twisted pair cable.
DMC-FO-HD
DMC-FO
Provides four DM outputs to feed up to four individual
DM receivers via multimode fiber cable.
Provides two DM outputs to feed up to two individual
DM receivers via multimode fiber cable. There are also dual,
independently switchable HDMI outputs and a balanced /
unbalanced stereo audio output.
DMC-HDO
Provides four HDMI outputs and two balanced/unbalanced
stereo audio outputs.
Check website (www.crestron.com) for product availability
23
Crestron DigitalMedia™ Design Guide
DM-MD6X1 Transmitter
The DM-MD6X1 is a low cost digital video distribution system designed for a small conference room or classroom. It can
replace three different products: analog video extenders, digital video extenders and USB extenders. It has a variety of input
formats built into the unit enabling you to get all your analog and digital signals into the system without any DM cards. It also
has a built-in power supply to drive connected DM devices so that they don’t need local AC power.




The DM-MD6X1 can be used as a stand-alone device
with transmitters and a room box
The analog inputs can be expanded with an MPS or
RGBHV switcher
The digital inputs can be expanded with an HDMI 8X1 or
8X2 switcher
Performs analog/HDMI audio conversion.
Video
The DM-MD6X1 supports all common video formats, both analog and digital, and converts them to a single video type to
simplify system design and wiring. The HDMI and DigitalMedia outputs are in parallel so they can be used simultaneously to
send video over structured wiring to the display and output to a local device.
Video Inputs
Video Outputs
 Composite (NTSC/PAL)
 DM
 HDMI
 S-Video (NTSC/PAL)
 Component (up to 1080p60)
 RGB up to 1920x1200
 HDMI connector, supporting HDCP on any of the
signal types below:
o HDMI signals up to 1080p60
o DVI signals up to 1920x1200
o DisplayPort (multimode) up to 1920x1200
 DigitalMedia, from any Crestron DigitalMedia
transmitter
Audio
The DM-MD6X1 cross converts all audio formats as well, so analog audio signals can be sent to a display as HDMI audio;
HDMI audio signals from laptops can be output to a traditional analog amplifier.
Audio Inputs
 HDMI and DM – 8-channel high-definition audio
 SPDIF
 Stereo analog audio
Audio Outputs:
 Stereo analog audio with volume control
 8-channel audio via the DM and HDMI outputs
USB
The DM-MD6X1 can process USB-HID keyboard and mouse signals from other DM devices in the system and relay them to a
connected PC or Mac. Separate USB signal extenders are no longer required to get control over your room PC from the lectern
or conference table. Best of all, no special drivers are required - just plug and play!
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Crestron DigitalMedia™ Design Guide
DM-MD6X1 Example Application Diagram
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25
Crestron DigitalMedia™ Design Guide
DigitalMedia Room Solution Boxes
DM-RMC-100, DM-RMC-100-F, and DM-RMC-100-F-LD
The DigitalMedia Room Solution Box features a low profile
design, perfect for installation behind flat panel displays and
above ceiling mounted projectors. It mounts on a standard
2-gang or 85mm European electrical box, and extends only
one inch from the surface. Connections for the display are all
positioned on the side of the receiver, while the DM and LAN
connections are made behind the unit within the electrical
box. An external power supply (wall wart) can be used when
using fiber cable.
The LD fiber Room Solution Box is used for long distance
(over 300m) fiber transmission (refer to “Select Wiring for
Each Run” on page 14).
Power and Heat Calculations
The DM-MD8X8 and the DM-MD16X16 both provide 24VDC power for connected DigitalMedia equipment,
such as transmitters and room solution boxes. Specifications are as follows:
DM-MD8X8
DM-MD16X16
Max Power
Consumption
211W
376W
Heat Dissipated
(BTU)
475
792
Power available
via DMNet
55W
110W
Room Solution Box and Repeater Power Consumption:
 DM-RMC-100 – 5W
 DM-RMC-100-F – 5W
 DM-DR – 3W
If more power is needed for DigitalMedia devices, it can be provided externally using the “EIG” jumpers to bring in
power from a standard 24V Crestron power supply. Refer to the manual for hookup information.
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Crestron DigitalMedia™ Design Guide
Step 3: Prewiring
HDCP Wiring Notes
When HDCP is not used, there are no midpoint limitations inherent to DigitalMedia (as with QuickMedia®).
When HDCP is used, too many hops in a single signal path (source to sink) can create potential HDCP problems.
The maximum number of hops is six (i.e. source to wallplate to switcher to receiver to display is three; repeaters
are not added to the count).
Contact Crestron Sales Support Services for design support.
Copper
When pre-wiring an installation using CAT5e or DigitalMedia Cable, ensure you have provided an area for repeater insertion
wherever one is required, as based on your distance calculations. Crestron recommends that you put the wire in a 2-gang box
or trim ring and leave a 1-foot loop available to splice in a repeater as necessary. There are foot markings on the DigitalMedia
Cable for determining length of run.
Fiber
When installing fiber optic cables, ensure that you have an adequate bend radius available in any conduit you are using. Most
fiber optic cables can support a bend radius of three inches under load. It is also recommended that you install spare fiber
optic strands in the event the fiber breaks.
Designers should also remember that fiber equipment can be powered locally or via 24VDC from the DM switchers. If they are
to be remotely powered, 18/2 or similar cable should be run for power.
Step 4: System Commissioning
The DigitalMedia system works out of the box to route any sources to any displays for cable testing. Once all of the equipment
is installed, the system requires commissioning. This can be done in 15 minutes from the front panel or the Toolbox tool, and
it verifies that all sources can be routed to all selected displays without causing problems. More information on this process is
available in the DM switcher manuals.
Check website (www.crestron.com) for product availability
27
Crestron DigitalMedia™ Design Guide
DM-MD8X8 Features



Eight input card slots (field upgradable)
Two output module slots with four outputs on each module (field upgradable)
Full audio and USB breakaway
NOTE: DMNet™ uses the same physical connectors as Cresnet®, but the two protocols are not compatible. Be sure you do not
cross-wire DMNet and Cresnet.
NOTE: The EIG connector on the DM product switchers is used to jumper in external power (in the same manner as the PAC2).
The switchers provide enough power (55 watts) for eight room solution boxes and five repeaters, so additional power is rarely
required.
DigitalMedia Device Quantity Limits
There are some HDCP limits as shown, below. Otherwise, there are no DigitalMedia maximum limits. The size of the system
can be increased as far as you like, subject to normal limitations with regard to memory, program size, etc.



No more than 128 devices total (each DigitalMedia switch counts as one device)
You cannot go more than six levels – i.e. hops - deep (each DigitalMedia switch counts as one level)
For design assistance, contact Crestron Sales Support Services.
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Crestron DigitalMedia™ Design Guide
DM Transmitters
For Sources Located Away From the Switcher
DM-TX-100 DigitalMedia HDMI Transmitter
 Connects to DigitalMedia switcher or receiver via DM Cable
 HDMI input
 USB HID port
 IR/1-way RS-232 port
 LAN port
 Rack or flush mountable
DM-TX-200 RGBHV + HDMI/DVI Signal Transport
 DigitalMedia transmitter for laptop AV and keyboard/mouse
commands over DM Cable
 Connects to DigitalMedia switcher or receiver via DM Cable
 RGBHV and HDMI input
 Audio input
 USB HID port
 Flush mount or in Wiremold® 6000 trough horizontally
DM-TX-300 + DM-TX-300-F 2X1 Switch DigitalMedia HDMI, DVI +
Component
The TX-300 allows any common AV signal over a single wire (video, RGB,
DVI, HDMI, DisplayPort – via a dongle, and the HDMI or DVI input). It
supports USB keyboard and mouse and provides an Ethernet port. This
combination enables the DM-TX-300 to replace three traditionally separate
pieces of equipment – the analog video extender, digital video extender and
USB extender. The DM-TX-300 can also be used to extend the life of an MPS
system by adding the DM-TX-300 to support digital and analog devices.











Connects to DigitalMedia switcher or receiver via DM Cable or fiber
DVI-I input
HDMI input
1 SPDIF digital audio input
2 analog stereo audio inputs
Component/S-video/composite video input
USB type “A” HID port
IR/1-way serial port
2-way RS-232 serial port
LAN port
Rack or flush mountable – perfect for use with Crestron FlipTops for a
clean tabletop solution
Check website (www.crestron.com) for product availability
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Crestron DigitalMedia™ Design Guide
DigitalMedia Repeater DM-DR
Reproduces signal for error-free delivery with DigitalMedia Cable. Up to three repeaters can be installed in a given signal path.
Installing the Repeaters
Repeaters mount to a standard 2-gang wall box.
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Crestron DigitalMedia™ Design Guide
Appendix A - The Device List
HDCP Limits in Source Devices
All HDMI sources that utilize HDCP limit the number of devices that may be connected at any given time. If too many devices
are connected to the source, content transmission stops until some devices are removed. These limits are not published by
device manufacturers.
DigitalMedia Source Testing
The Crestron DigitalMedia solution tests each source HDCP limit when the system is commissioned. It allows the installer to
limit the number of zones for each source to minimize the number of connected devices. Potential problem areas are pointed
out by the DigitalMedia system. Installation problems can be avoided by selecting source equipment that have greater HDCP
limits and designing around any low HDCP limit sources.
During system design, the number of devices connected to each source should be counted, to ensure that they fall under the
device’s HDCP limit. To count the total number of devices in the system, add up the number of HDMI devices that are in the
zones where the source will be used, including AV receivers and displays. Do not count the DigitalMedia system.
In this example, any source with HDCP limits of three or more is problem-free. If the source device’s HDCP limit is too low, the
source can still be used but cannot be viewed in all zones simultaneously.
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31
Crestron DigitalMedia™ Design Guide
Device List
The following is a list of the devices Crestron has tested, and the maximum number of devices each supports.
HDCP Limits - Set Top Boxes
Motorola DCT6412 (Comcast)
Scientific Atlanta 8300HD (Cablevision)
TivoHD
DirecTV HR21
EchoStar Europe Vi P211
Echostar STB VIP-222
1*
1*
16
N/A**
16
16
HDCP Limits - HD Disc Players
Panasonic DMP-BD30
Toshiba HD-A20
Toshiba HD-A35
LG Super Multi-Blue
Motorola VIP 1200
Sony DVD-P DPX - 2380
Sony Blu-ray Recorder BDZ-X100
Sony BD Player Blu-ray player BDP-S5000ES
Philips Blu-ray player BDP 7200
3
10
16
16
16
9
8
16
16
HDCP Limits - Game Systems/Other
Apple TV
Sony PS3
XBOX 360
Anchor Bay Edge 101 (Scaler)
16
14
16
8
* These sources were tested with firmware from the indicated cable company. Other cable companies’ products may have
different limits.
** DirecTV does not currently use HDCP, but may add it in the future without notice.
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Crestron DigitalMedia™ Design Guide
Glossary
Video Resolution Terminology
1080i
An HDTV standard that specifies an interlaced resolution of 1920 x 1080.
480i
480 interlaced; a form of standard definition digital television (SDTV) that approximates the quality of analog television but not
considered high definition television (HDTV). Even though the native resolution of DVDs is 480p, they are viewed at 480i on an
NTSC analog television.
480p
480 progressive; a form of standard definition digital television (SDTV) comparable to VGA computer displays but not
considered high definition television (HDTV), though 480p is discernibly cleaner and slightly sharper than analog television.
The native resolution of DVD is 480p, but that resolution can be seen only if a DVD player outputs a progressive scan signal
and the DTV has progressive scan or component video inputs; it is also known as EDTV.
720p
720 progressive; one of two currently used formats designated as high definition television in the ATSC DTV standard, this
technology comprises 720 vertical pixels and 1,280 horizontal pixels. The p stands for progressive, as opposed to interlaced,
scanning, which is used in the other accepted HDTV standard, known as 1080i. Contrary to myth, 720p is not inferior to 1080i;
720p has fewer lines but also has the advantages of progressive scanning and a constant vertical resolution of 720 lines,
making it better able to handle motion.
Deep Color
A color depth standard associated with high definition TVs and video gear that include HDMI 1.3 connections. The Deep Color
standard supports 10-bit,12-bit and 16-bit color depths, up from 8-bit, which is the current standard for consumer video.
DigitalMedia supports all but the 16-bit color depth. All earlier versions of HDMI just supported 8-bit color. (Because video
is based on three primary colors, you'll sometimes see Deep Color described as 30-bit, 36-bit and 48-bit.) A higher color bit
depth enables finer gradations between different shades of the same color, for smoother gradients and reduced color banding.
Deep Color gives TVs the potential to display billions rather than millions of colors, but in order to see that improvement, the
entire video production chain has to use it (camera, editing, format, player, display).
Down-convert
In DTV, the conversion from a higher resolution input signal number to a lower one. For example, some DTV receivers can be
set to down-convert an HDTV 1080i signal to a standard 480i signal that any TV can display.
Check website (www.crestron.com) for product availability
33
Crestron DigitalMedia™ Design Guide
Video Display Terminology
Aspect Ratio
The ratio of width to height in a video picture or other graphic image. Traditional U.S. TV broadcasts and computer monitors
feature a 4:3 aspect ratio; HDTV has a 16:9 ratio.
16:9
Sometimes expressed as 16 x 9 or 16 by 9 (known as 1.78:1 in the film world). The standard DTV widescreen television
screen size, or aspect ratio, which is 16 arbitrary units wide by nine arbitrary units high, as compared to a standard TV aspect
ratio of 4:3. The phrase describes the shape of a TV set or program, not an actual inch measurement.
4:3
Standard “square” NTSC TV screen size aspect ratio of four arbitrary units wide by three wide arbitrary units high; often
expressed as 4x3 or 4 by 3. It was originally known as the Academy Ratio (as in Academy of Motion Picture Arts and Sciences,
the film industry organization that awards the Oscars) prior to 1954 and the introduction of widescreen aspect ratio film
formats; also known in the film world as 1.33:1.
Anamorphic
Adopted from the film technique of shooting a widescreen image on a square 35mm frame, it's the process of compressing
widescreen images to fit into the squarer standard 4:3 television signal. The images are then expanded for viewing in their
original format on a widescreen display device. Widescreen or letterboxed DVDs that are not anamorphic have less detail
when projected on a widescreen monitor. In other words, a non-anamorphic widescreen DVD is designed to be shown
letterboxed on a standard “square” TV but appears with a black box all around the image when shown on a larger 16:9
widescreen TV. To fill a 16:9 screen, a non-anamorphic DVD has to be stretched, resulting in loss of resolution and detail.
Conversely, a DVD that is anamorphic, enhanced for 16:9, or enhanced for widescreen, delivers 33 percent more resolution
than regular letterboxed transfers. It was designed to be shown on a 16:9 TV, and does not need to be manipulated to fit.
When one of these DVDs is shown on a "square" TV, it is often subject to anamorphic down-conversion artifacts unless the
TV has a vertical compression feature.
Anamorphic down-conversion
Processing present in all DVD players that converts the image from an anamorphic DVD for display on a regular 4:3 TV.
In the initial setup of a DVD player is a choice between a 16:9 or a 4:3 TV; the 4:3 options engage this processing,
which often introduces artifacts such as jaggies and undulations during pans.
Component video
The elements that make up a video signal, consisting of luminance and two separate chrominance signals, expressed either
as Y R-Y B-Y or Y Pb Pr.
DisplayPort
A digital display interface standard put forth by the Video Electronics Standards Association (VESA) that defines a new licensefree, royalty-free, digital audio/video interconnect, intended to be used primarily between a computer and its display monitor
or a computer and a home theater system.
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Crestron DigitalMedia™ Design Guide
DVI
Digital Visual Interface; a digital interface specification created by an industry consortium, the Digital Display Working Group.
This universal standard for connecting flat panel monitors is also used for data projectors, plasma displays, and digital TVs.
Using a DVI connector and port, a digital signal sent to an analog device is converted into an analog signal (if the device is
digital, such as a flat panel monitor, no conversion is necessary). There are three different DVI configurations: DVI-A for analog
signals, DVI-D for digital signals, and DVI-I (integrated) for both analog and digital signals.
DTV
Digital television is a generic term that refers to all digital television formats, including high definition television (HDTV) and
standard definition television (SDTV).
HDMI
High Definition Multimedia Interface. USB-like digital video connectivity standard designed as a successor to DVI. Transmits
both digital audio and video signals and incorporates HDCP digital copy protection.
Interlaced scanning
Scanning method used by the 1080i HDTV format. As opposed to progressive scanning, in which the CRT's electron beam
scans or “paints” all lines at once, interlaced scanning TVs paint odd-numbered lines in succession, then go back and fill
in the remaining even-numbered lines. This method is more prone to artifacts and less stable than progressive.
Progressive scan
A method of displaying images on a CRT monitor or a high definition TV in which all the lines of a picture are drawn in one
quick burst, from left to right and from top to bottom. Compare this to interlacing, in which every other line is displayed in
two successive swoops to form a complete picture.
SDTV
Standard definition television. Digital television format that includes 480-line resolution in both interlaced (480i) and
progressively scanned (480p) formats; offers discernible improvement over conventional analog NTSC picture resolution,
with less noise; similar to DVD or satellite TV quality but not considered high definition.
Widescreen
Image with an aspect ratio greater than 1.33:1 or a picture wider and narrower than a traditional television image. Typically
refers to TVs in the 16:9 aspect ratio.
Y Pb Pr
Luminance, and two chrominance channels of blue minus luminance and red minus luminance. This technical shorthand for
component video is also written as Y Cb Cr (or Y R-Y B-Y).
Check website (www.crestron.com) for product availability
35
Crestron DigitalMedia™ Design Guide
Encoding Terminology
AC-3
This digital surround sound format for home audio is called Dolby Digital in theaters. It is a 5:1 format, with six separate audio
tracks. AC-3 has been chosen as the official sound format for digital TV and is commonly used to encode DVD soundtracks.
Authentication
Authentication ensures that digital data transmissions are delivered to the intended receiver. Authentication also assures the
receiver of the integrity of the data and its source. The simplest form of authentication requires a username and a password
to gain access to a particular account. But authentication protocols can also be based on secret key encryption, such as DES,
or on public key systems using digital signatures.
DRM
Digital Rights Management is a secure technology that enables the copyright owner of a piece of intellectual property (such as
a music, video, or text file) to specify what a user can do with it. Typically, this is used to offer downloads that can't be played
or burned to CD without paying for a license.
HDCP
High-bandwidth Digital Content Protection. A copy protection scheme developed by Intel used in conjunction with DVI and
HDMI connections.
KSV
A set of numbers transmitted between HDCP-protected sources and sinks during the authentication ‘handshake’ to validate
that the devices are authorized to receive the content. Some HDMI sources have limited buffer space to hold KSVs and as such
can only be routed to a few HDMI devices before their buffer overflows and content playback stops.
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Check website (www.crestron.com) for product availability
Crestron Electronics, Inc. 15 Volvo Drive | Rockleigh, NJ 07647
Tel: 800.237.2041 / 201.767.3400 | Fax: 201.767.1903
www.crestron.com
Printed in USA Doc. 4789F 1/30/09
Specifications subject to change without notice
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