Blu-Ray HD Playback for Video Projection

Blu-Ray HD Playback for Video Projection
Blu-Ray HD Playback for Video Projection
Author: Mark C. Brown
Systems Engineer, BEE
www.reachcomm.net
Originated: 9/18/11 Revised: 9/25/11
Introduction
Houses of worship, schools, and users of corporate conference rooms often want to use Blu-ray players with
their video projection systems and flat panel displays, and understandably, they expect HD image quality
when they do this. However, often they encounter difficulties, or questionable image quality (or no image)
when they try to do this, and the solution is not always easy to sort out. In writing this application note, I’m
hoping to help de-mystify this topic.
I’ll begin with a summary of the basic principles to consider, followed by my observations, and a list of
references for more information on the details.
Basic Principles
1. HD = High Definition (“Hi Def”): 1080p, 1080i, 720p, 720i, resolutions, 16:9 aspect ratio
2. SD = Standard Definition: 480i resolution, 4:3 aspect ratio
3. Typical Video Projector Resolutions: The most common native resolutions for projectors are XGA (1024
x 768, aspect ratio 4:3) and WXGA (1280 x 800, aspect ratio 16:10), at the time of this writing.
Essentially a WXGA projector will achieve the full benefit of a 720p source, i.e. 1280 x 720 (i.e. 16:9,
HDTV aspect ratio). In this sense, a WXGA projector is usually considered High Definition.
4. Blu-ray 1080p resolution: This translates to a pixel field of 1920 x 1080. To get the full advantage of Blurays’s maximum 1080p resolution, you would need a video projector with the same native resolution or
better. Such a relatively high resolution is possible, but not the most common for projectors at the time of
this writing. (Even so, projectors with WUXGA 1920 x 1200 resolution are readily available, although
more expensive.)
5. High Definition Signal Methods: Baseband video with high definition resolution can be transmitted over
analog RGBHV (e.g. using a VGA HD15 connector, or five separate BNC connectors for RGBHV), and
also over analog component video (typically 3 RCA connectors on consumer gear), as well as digital
(DVI or HDMI) interconnection schemes.
6. VGA-type Sources for High Definition Images: VGA-type sources of higher resolution, such as WXGA
(1280 x 800) and WUXGA (1920 x 1210) can be considered similar in resolution to “High Definition”
resolutions, also known as HDTV resolutions. (In this sense, I use the term VGA not as a resolution, but
as an analog video connection format used for transmission of RGBHV signals over HD15 connectors.)
7. DVI Sources for High Definition Images: DVI stands for “Digital Video Interface.” On computers, a
connector type known as a DVI connector is typically used, but DVI signals can be used on other types of
connectors. In particular, HDMI uses DVI signals for video transmission. Computers use DVI to provide
video images with resolutions such as XGA, WXGA, and WUXGA resolutions that are common in video
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projection systems. DVI works well for higher resolutions, with the resulting image being less affected
by noise and other influences.
8. HDMI: This stands for High Definition Multi-media Interface. It includes both DVI video and SurroundSound audio signals on a single, compact connector. When used with a projector system in an auditorium
or similar large room, typically only the DVI video signals from the HDMI connector are used by the
projection system.
9. Another major issue – HDCP: High-bandwidth Digital Content Protection (also sometimes unofficially
defined as “High Definition Copy Protection”) is a copy prevention scheme intended to protect
commercial producers of high-definition content. This is a form of digital rights management for video
recordings. It requires that all devices in a digital video signal chain must be HDCP-compliant, to make
sure none of them are copying the content. This means that any projector (or other display device) must
be HDCP-compliant. The only way the display can be compliant is if it has a digital video input port,
such as DVI or HDMI, and even in that case it must have internal electronics and software that make it
HDCP-compliant. Otherwise a Blu-ray player will not send its highest definition content to the projector
or display. A projector that has a DVI input port does not guarantee that it is HDCP-compliant. The
projector manufacturer will specify that the unit is HDCP-compliant, if it is.
10. High Definition over Digital connections (HDMI, DVI) vs. Analog (Component Video): High Definition
resolutions of 1080p and higher can be transmitted over analog connections, specifically over Component
Video (analog red, green & blue jacks, signals Y- Pb- Pr). However, Blu-ray players are designed so that
they send a maximum resolution of 1080i over component video, up until 2011 (see more on this below,
i.e. “Analog Sunset”). The intent is to prevent or discourage copying of high definition content that is
produced commercially. This cannot be controlled over existing formats of analog connections. With
DVI (which is also used within HDMI), the format of this digital connection facilitates HDCP control, so
high def producers want this to be the way high def content is delivered to your display device (TV, flat
panel display or projector).
11. Possible Big “Gotcha” When You Have an HDCP Compliant Switcher or DA: If you have a Blu-ray
player (or other HDCP compliant source, such as a MacBook Pro) connected by HDMI or DVI to an
HDCP compliant switcher or DA (i.e. Distribution Amplifier, such as HDMI or DVI splitter), you will
likely have a problem unless everything else is HDCP compliant. For example, maybe your projector is
not HDCP compliant, or maybe your output cabling from the switcher or DA does not facilitate HDCP
(e.g. if you use VGA cabling instead of DVI or HDMI cabling). In this case, you’re likely to get a black
screen or screen full of snow. This is because the HDCP compliant source (e.g. the Blu-ray player or
MacBook Pro), having detected an HDCP compliant device (the switcher or DA) is sending an HDCP
encoded data stream. However, the cabling or the next device in the chain does not support this, so you
get the black screen or a screen full of snow.
12. Is SDI a Solution with Blu-ray Players? – The answer is “No.” By definition, SDI (Serial Digital
Interface) does not carry HDCP encoding, or any other form of copy protection in the digital signal. This
is because SDI, also sometimes referred to as HD-SDI when used for Hi-Def, is a video signaling
standard intended for broadcast & video production studios, and similar professional video environments.
It is also found in high-end video projection systems, because of the advantages of SDI cabling and other
factors. On the other hand, Blu-ray players are consumer devices, designed for home use and similar
situations. SDI is definitely intended for High Definition capability in professional environments, but not
for Blu-ray players with only HDMI out and HDCP-compliance. (Of course, SDI can be used for hi def
signals converted from analog component video directly to SDI.)
13. “Analog Sunset” for Component Video on Blu-ray Players: This is scheduled to happen over the period
of 2011 to 2014, as detailed in various references below. Basically, starting in January 2011, new models
of Blu-ray players do not pass HD over component video connections. Probably many new models (and
eventually most) will discontinue having component video connectors.
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Observations
If you want to use a Blu-ray player to get high definition resolutions from commercially produced content,
used in combination with a video projector or flat panel display, there are 2 ways to do this.
First, for projectors or displays that don’t have HDCP-compliance, or even if they do, if you’re using a nondigital video connection (e.g. VGA or RGBHV, instead of DVI or HDMI), then you need a pre-2011 Blu-ray
player that has component video output. This can be connected through a switcher/scaler and DA, or directly
to the projector or display. You would typically use the Blu-ray player for 720p output resolution in this case,
which will line up most closely with the native resolution of a WXGA projector. (Alternately, the best
resolution you can get from this Blu-Ray player is 1080i out of the component video connectors, but this
would require a projector or display with a native resolution of WUXGA or better, and a pre-2011 Blu-ray
player.)
Second, for projectors and displays that have HDCP-compliance, then you need to use a digital video
connection path (i.e. DVI or HDMI) to connect from the Blu-ray player to the projector or display. If you go
through a switcher/scaler or similar, then the switcher/scaler must also be HDCP-compliant, and you need to
use digital video ports for both input and output on the switcher, as well as a digital video input port on the
projector or display. If you use a DA, it must also be HDCP compliant, and you need to use digital ports in
and out on the DA.
Note, these concerns apply to Blu-ray players used for high definition commercial content. If you’re using a
computer for high resolution graphics, or for showing your own in-house high definition video clips, or
you’re sending high resolution video from an in-house camera mixer or similar, then you can send these high
resolution signals over any existing VGA or RGBHV cabling without changing anything, and you will get
high resolution results. Or at least you’ll get the highest resolution possible for your projector or display, and
for your signal processing. It’s the Blu-ray player, or other HDCP compliant device, that’s causing a
resolution limitation.
For new projectors, new switcher/scaler units, and new video cabling installations, it is clear that the issue of
HDCP compliance and the related digital cabling required must be part of the decision making process,
including whether the users require this capability. Trying to accommodate HDCP compliance adds
headaches and significant cost, but with the demise of high def signals on component video outputs from Bluray players, this issue is forced into the discussion for new systems. As part of this discussion, it must be
considered that protected material is usually restricted from playback in public and commercial spaces, and
this fact also deserves some thought.
Conclusion
By understanding the basic principles involved, and considering my observations discussed above, you should
be able to achieve the best possible image quality for your specific system when you play DVDs or BDs, even
if it isn’t the highest resolution possible from your Blu-ray player. In most cases you can achieve some form
of high def, although it’s getting harder with the design changes that are being implemented on new Blu-ray
players.
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References:
1. http://en.wikipedia.org/wiki/High-definition_video - Wikipedia definition for High Definition Video
2. http://en.wikipedia.org/wiki/Component_video - Wikipedia definition for Component Video
3. http://en.wikipedia.org/wiki/Serial_digital_interface - Wikipedia definition for Serial Digital Interface,
for video (also known as SDI)
4. http://www.serialdigital.com/tag/hdcp/ - “MacBook Pro: Black screen or ‘snow’ over DVI into
switchers’ – Blog article by Steve Wylie, Feb 21, 2010
5. http://www.crutchfield.com/S-nCyxM5ipkNj/learn/learningcenter/home/dvd_faq.html Blu-ray and DVD
Player FAQ , hosted by Cutchfield, author Loren Barstow; August 26, 2011
6. http://news.cnet.com/8301-17938_105-20042864-1.htmll “Component video is missing or crippled on
2011 Blu-ray players: Here’s why”; cnet News article, by Matthew Moskovicak; March 17, 2011
7. http://www.osnews.com/story/22897/2010_Analog_Sunset_the_End_of_Component_Video “2010:
Analog Sunset, the End of Component Video” - OSnews article, by Thom Howards; Feb 20, 2010
8. http://forum.videohelp.com/threads/314684-How-good-is-playing-Blu-ray-through-component-video
“Thread: How good is playing Blu-ray through component video?”- forum that specifically discusses
aspects impacting a video projector; 1st post – 1/5/2010
9. http://www.zeevee.com/files/documentation/AllAbouttheAnalogSunset.pdf White-paper, “The Future of
HD Over Component Video As of May, 2010”- posted on ZeeVee (manufacturer) website
10. http://www.zdnet.com/blog/government/so-now-that-the-hdcp-key-is-loose-what-does-it-all-mean/9415
“So now that the HDCP key is loose, what does it all mean?” - ZDNet article, by David Gewitz; Sept 20,
2010
11. http://en.wikipedia.org/wiki/High-bandwidth_Digital_Content_Protection Wikipedia definition for
HDCP
12. http://www.commercialintegrator.com/article/challenges_of_hdmi_installs/ “Challenges of HDMI
Installs”, online article for Commercial Integrator magazine, by CI staff; Oct 26, 2010
13. http://www.hallresearch.com/app/webroot/files/articles/DisplayPort_White_Paper.pdf White-paper,
“Display Port
14. http://www.ecoustics.com/electronics/products/articles/122868.html - “DVI vs. HDMI vs.Component
Video – Which is Better?” - article on ecoustics.com website,, by Admin; Feb 14, 2005
15. http://www.convergent-av.co.uk/article1.html - “DVI/HDMI - What you need to know!” - article on
Convergent AV website; includes a brief discussion of SDIcopyright 2003-2011
16. http://media.extron.com/download/files/whitepaper/analog_sunset.pdf “Analog Sunset” Dymystified –
Rev 1.0 - Extron whitepaper, concerning the implications of this topic for Blu-Ray players – June 3, 2010
17. http://www.extron.com/download/files/whitepaper/hdcp_wp.pdf “HDCP – A Technical Overview”–
Rev 1.0 - Extron whitepaper – June 11, 2009
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18. http://www.extron.com/download/files/whitepaper/drmavprofessionalwp.pdf “DRM for the A/V
Professional”– Rev 1.0 - Extron whitepaper, concerning Digital Rights Management – January 27, 2010
19. http://www.extron.com/download/files/whitepaper/theabcs_wp.pdf “The ABCs of Digital Video
Signals”– Rev 1.0 - Extron whitepaper – June 8, 2009
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