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7. Device Connections and Interfaces

7.1 What type of video outputs do consumer electronics BD video players offer?
7.2 What issues are raised when playing commercial BD movies over analog and digital video connections?
7.3 What is HDMI?


7.1 What type of video outputs do consumer electronics BD video players offer?
Typical BD consumer electronics (CE) video players offer analog (e.g. component, S-Video, composite) as well as digital (e.g. HDMI, DVI) video outputs.

 

7.2 What issues are raised when playing commercial BD movies over analog and digital video connections?

Digital Video Connections
All commercial BD movie discs (prerecorded/replicated) are encrypted by the Advanced Access Content System (AACS), designed to deter unauthorized copying. AACS allows a BD device to transmit video over a digital interface (HDMI, DVI, DisplayPort, MHL) only if it implements High-Bandwidth Digital Content Protection (HDCP), which is an encryption system to prevent making perfect duplicates by intercepting the digital signal. Many older televisions, monitors, video cards and A/V receivers  do not support HDCP, so BD devices and computers will often use analog connections (from which, of course, copies can more easily be made).

By way of background, United States Federal Communications Commission (FCC) regulations [47 CFR 15.123. 2005] specify dates by which certain percentages of new HD (720p/1080i) televisions marketed as "digital cable ready" must incorporate either HDMI or DVI interfaces equipped with HDCP (see table).

Percentage of New U.S. HD Digital Cable Ready Televisions
Required to Incorporate HDMI or DVI with HDCP
FCC Regulation Compliance Date Television Screen Size
13" – 24"
Television Screen Size
25" – 35"
Television Screen Size
36" +
July 1, 2004 50%
July 1, 2005 50% 100%
July 1, 2006 100%
July 1, 2007 100%

In Europe, HD (720p/1080i) capable devices conforming to the European Information, Communications & Consumer Electronics Technology Industry Association’s (EICTA) "HD TV" and "HD Ready" requirements must also incorporate either HDMI or DVI interfaces outfitted with HDCP.

Analog Video Connections
As of now, it should be possible to view many commercial BD movies at full resolution on televisions (or other displays) using analog composite (RF, composite, S-Video), component (YUV, YPbPr and Y,R-Y,B-Y) or computer (VGA, SVGA, XGA, SXGA, UXGA) video connections. However, some current and future movie releases may be designed to force BD playback devices to significantly downgrade image quality. Eventually, new BD equipment will be designed to make it impossible to play commercial content over their analog video connections.

To make it less attractive to use analog connections for copying, AACS incorporates an Image Constraint Token (ICT). If this feature is employed when the movie disc is mastered the ICT will instruct a BD playback device to reduce its video image quality to 960×540 (by e.g. discarding, dithering or averaging pixels, etc.) if connected through its analog outputs. But, because so many existing devices must use their analog connections, it is expected that most commercial movies will not resort to the ICT restriction. Be aware, however, that not all content publishers may decide to follow this practice. The future therefore is uncertain. At present, movies are required to disclose, either on their packages or at point of sale, if they trigger the ICT.

Part of AACS’s collection of features, as well, is a Digital Only Token (DOT). To further remove the possibility of analog copying the DOT functions somewhat like the ICT but instead instructs the BD playback device to transmit through only its (HDCP protected) digital outputs. Initially, AACS license agreements prevent content publishers from utilizing the DOT but all BD playback devices must still be able to enforce the restriction in the event it is eventually permitted. At this early stage in the market, it is unclear the terms under which this might happen.

Beyond the ICT and DOT, AACS license agreements also implement "analog sunset" clauses that will eventually cripple and ultimately prevent new BD playback devices from transmitting commercial BD movies over their analog connections (see table).

Advanced Access Content System (AACS)
Analog Sunset Requirements
Sunset Date Requirements
Dec. 31, 2010 New playback devices limit analog outputs to standard definition (SD) interlace modes only (composite, S-Video, 480i component, 576i component TBD)
Dec. 31, 2011 Existing playback devices limit analog outputs to standard definition (SD) interlace modes only (composite, S-Video, 480i component, 576i component TBD)
Dec. 31, 2013 No analog outputs permitted

 

7.3 What is HDMI?
First appearing at the end of 2002, the High-Definition Multimedia Interface (HDMI) is a high bandwidth digital interface designed to connect together devices such as Blu-ray Disc (BD) and DVD players as well as camcorders, game consoles, set-top boxes, A/V receivers, digital televisions and home theater projectors. It carries uncompressed high definition (HD) video, compressed or uncompressed multi-channel audio and optional control information using a single cable (up to 15 m in length). HDMI is backward compatible with the Digital Visual Interface (DVI) by means of a converter or adapter, but with the loss of control information and the need for separate audio connection (DVI carries only video signals).

Since its release in December 2002 (version 1.0), HDMI has been upgraded several times to add new features (v. 1.1 in May 2004, v. 1.2 in Aug. 2005, v. 1.2a in Dec. 2005, v. 1.3 in June 2006, v. 1.3a in Nov. 2006, v. 1.4 in June 2009, v. 2.0 in Sept. 2013, v. 2.0a in Apr. 2015). Products incorporating version 1.3 modifications began appearing at the end of 2006. Among its advancements are greater bandwidth (10.2 Gbps compared to 4.95 Gbps), deep color (30/36/48-bit RGB or YCbCr compared to 24-bit), broader color space (xvYCC/x.v.Color) and the ability to carry BD’s lossless compressed digital audio formats (Dolby TrueHD and DTS-HD Master Audio).

Version 1.4 incorporates further improvements including integrated Ethernet (100Base-TX), an audio return channel (Dolby Digital, DTS, PCM), support for additional color spaces (sYCC601, Adobe RGB, Adobe YCC601) and new physical connectors (micro, automotive) as well as increased bandwidth to accommodate higher 4K x 2K (Quad HD) resolutions (3840 x 2160 24p/25p/30p, 4096 x 2160 24p) and three-dimensional (3D) video (1080 24p, 720 60p).

The latest major change (v. 2.0) expands the range of video (4K@50/60, 21:9, dual streams), audio (multi-stream, 32 channels, 1535kHz, dynamic auto lip-sync) and Consumer Electronics Control (CEC) options,  while version 2.0a adds support for High Dynamic Range (HDR).

Developed by Hitachi, Matsushita, Philips, Sony, Thomson, Toshiba and Silicon Image, the HDMI specification is administered and promoted by HDMI Licensing, LLC.

HDMI Version Comparison
(simplified)
Feature Support Version 1.0 Version 1.1 Version 1.2 Version 1.3 Version 1.4 Version 2.0
Standard connector (Type A) X X X X X X
Dual-link connector (Type B) X X X X X X
Consumer Electronics Control (CEC) X X X X X X
sRGB color space X X X X X X
YCbCr color space X X X X X X
Uncompressed digital audio (8-ch/192kHz/24-bit max.) X X X X X X
DVD-Audio (DVD-A)   X X X X X
Super Audio CD (SACD), Direct Stream Digital (DSD)     X X X X
Deep color       X X X
Automatic lip sync       X X X
Mini connector (Type C)       X X X
Lossless compressed digital audio (Dolby TrueHD, DTS-HD MA)       X X X
x.v.Color (xvYCC) color space       X X X
Audio return channel         X X
4K x 2K resolution (Quad HD)         X X
Three Dimensional (3D) video         X X
Integrated Ethernet (100Base-TX)         X X
Micro connector (Type D)         X X
Automotive connector (Type E)         X X
sYCCC601 color space         X X
Adobe RGB color space         X X
Adobe YCC601 color space         X X
4K@50/60           X
CEC Extensions           X
Dual-stream video           X
Multi-stream audio           X
32-channel audio           X
1536 kHz audio           X
21:9 aspect ratio           X
Dynamic auto lip-sync           X

HDMI cable

Figure 7.1: HDMI Cable (source: HDMI Licensing, LLC.)

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