DVI
– a Practical Guide
Draft Version 0.83. July 16, 2003
This guide is my
attempt to capture the collective information on DVI in AVS Forum. Hopefully it
will stem the wasted tide of consumer dollars going into non-DVI devices, and
help forum members in their adoption of DVI.
This guide is
currently in draft form, and I need your help to get it to a level of
completeness and accuracy.
I am in no way affiliated with anyone in consumer entertainment business. The views in this guide are purely my own as a consumer.
Arun Gupta
Contents
DVI brings a
Quantum Jump in Picture Quality
Set Top Boxes
– HDTV Satellite/Cable Receivers and PVRs
PC Graphics
Cards with DVI Output
Links
to Related AVS Forum Threads and Guides
DVI - A Practical Guide: Thread Latest Version of this Document
My unofficial guide to Samsung HLN series: Thread Document
Introduction to DVI
As we change from
analog to digital for everything in consumer electronics, it is inevitable that
connections between our devices also become digital. For audio, this is already fully
underway. For video, DVI (Digital Video
Interface) represents this
inevitable change.
The most important lesson I've learned in 6 months of owning a Samsung DLP TV and few weeks of Bravo D1 player is that analog Component connections are history and digital DVI connections are the only way forward. There is a night and day difference in Picture Quality when we switch from Component to DVI connections. As we move towards all things digital:
Digital PQ Nirvana
= Digital Signal -> Digital DVI Connection -> Digital Display
Digital signals
include SD (Standard Def.) programs, HD (High Def.) programs, DVD playback, or
PC input. A digital display is any fixed
pixel display (LCD, DLP, LCoS, Plasma), as well as HDTV CRT displays.
Let me also
emphasize that DVI is video only. It
does not carry any audio. HDMI will have
both.
For more in-depth
info on DVI, see DVI Overview and this DataPro page.
DVI, however, comes with a big restriction - called HDCP
(High-bandwidth Digital Content Protection).
It is
Within the next
year or so, DVI will evolve into HDMI (High Definition Multimedia Interface), its second generation successor. HDMI
includes audio, has a smaller connector plug, and a bigger distance range. Fortunately, HDMI will be backward compatible
with DVI. See the in-depth section on HDMI – The Evolution of DVI.
DVI brings a Quantum Jump in Picture Quality
It was a surprise to me, and it is a surprise to most people when they first experience a DVD played back through a DVI connection. "Jaw dropping" is the phrase often used, and it describes my reaction. Except in my case I had no prior clue - so it contained shock and confusion as well. My wife kept insisting that the DVD we were playing was high definition. There are hundreds of reactions like mine in this forum, and now there are reviews in many publications attesting to the phenomenal quality difference. See DVI Quotes.
Why is that? DVI is not magically adding quality to your signal, it is Component that has been degrading the signal – we just didn’t how badly.
Component: When you use a component connection, your original digital signal is converted to analog, then it is sent over to the TV and becomes susceptible to noise, then it is converted back to digital by the TV. This dual conversion introduces conversion artifacts, plus the transmission can pick up noise.
DVI: In a DVI connection, the original digital signal is passed to the TV digitally in its original pristine condition.
In the past, when you had poor quality input signal and a poor fidelity TV, you could get by with component connections. Now you have high quality inputs (HD, PC or DVD) and high fidelity digital TVs (even CRT HDTV’s are digital in this context), so the component connection makes no sense. DVI is the only sensible option.
Indeed it is my opinion that HDTV without DVI is an oxymoron. Why go through all the trouble of creating an expensive digital setup, generating a high quality digital signal into a high fidelity digital display, if you are going to throw the analog Component monkey wrench into it.
And until you've switched to DVI, don't look for other culprits for video artifacts - clay faces, dithering, motion artifacts, etc. Find out first how many are actually introduced by your component connection.
Let's move on with DVI.
The State of DVI
Most consumers are not knowledgeable about DVI. Until a few months, I wasn't aware of the impact it could have. This AVS forum represents the most knowledgeable A/V consumers. I'd venture to say that most of us have also been in the dark until recently.
It is much more surprising, however, that most manufacturers are also in the dark. In a recent research in replying to a question on this forum, I was shocked to find out how many $10,000+ recently introduced displays are without DVI support. Satellite and Cable providers, as well set-top receiver and PVR manufacturers also have a mixed scorecard. DVD player vendors have also been a deep state of slumber and are just beginning to wake up.
In fairness to all of us, HDCP and the changeover to HDMI do bring a certain amount of confusion and uncertainty to DVI.
DVI - What We Need to Do
Suggestion General 1: If you are making a new
consumer electronics video item purchase, I strongly urge you to make sure it
has DVI support. Devices with DVI
inputs, such as televisions, should also have analog inputs so that you can
decide at what pace you want to move to DVI.
Suggestion General 2: All new equipment with DVI
inputs must also have HDCP support.
Suggestion General 3: For equipment with DVI outputs,
I think it is OK for consumers to buy ones without HDCP support, although
Suggestion General 4: If you have equipment with
DVI input ports that don’t support HDCP, look for equipment that has a DVI
output but doesn’t enforce HDCP – e.g. Bravo D1 DVD player. Buy them quickly before such devices become
non-existent.
Suggestion General 5: If you have an existing
item with DVI/HDCP support, test this capability as soon as possible. If it doesn’t work as advertised, demand
resolution.
Suggestion General 6: If you have a current A/V
setup that you are happy with, weigh the pros and cons of when you should
switch to DVI for each of your equipment.
Television is of course the first item to switch.
Televisions with DVI Inputs
State of
Note on CRT TVs: Since even a CRT HDTV is first converting the signal to digital for processing, CRT sets also benefit from the switch to DVI - although it may not be to the same extent as fully digital televisions.
Suggestion TV 1: Do not buy a new TV/monitor (over $1000) without
DVI/HDCP input.
Suggestion TV 2: I strongly recommend against buying a fixed pixel
TV (non-CRT) that has a non-standard native resolution. It will make 1x1 pixel mapping impossible,
and you will never achieve the best PQ.
I know this is a tough one, because non-standard resolutions seem to
have proliferated in front projectors, plasmas and some RPTV’s.
Suggestion TV 3: When you are buying a new expensive TV, it is more
than likely that a retail store is displaying the picture through a component
connection – which doesn’t help you much.
My advice is take a DVI equipped DVD player with some good reference
(Superbit?) DVD’s with you to test out the TV.
That way you can also compare television PQ in multiple stores.
Suggestion TV 4: Ideally, televisions should have 3 DVI inputs just
like they generally have 3 component inputs today. No televisions with 3 inputs are currently available,
and very few with 2 inputs. Look for
them starting in 2004. Meanwhile, we
have to use external DVI switches, and they are not quite there yet.
Suggestion TV 5: When you
connect your devices to fixed pixel televisions (LCD, DLP, LCoS, Plasma), it is
very important that you try to get one to one pixel mapping for best PQ.
One to One Pixel Mapping: If you have a fixed pixel television, then you will gain significantly in picture quality if you can get one to one pixel mapping to the NATIVE resolution of your TV. Of course, this is only possible if the original signal is the same as the native resolution. For example, if you have a 1290x720 pixel TV, you should make sure that an ABC 720p broadcast ends up in your TV without any scaling and 1x1 pixel mapped. Same is true for PC inputs. If your signal is going to be scaled, you want to make sure that it is scaled ONLY in one place, the place that has the best scaler.
DVI Compatibility Table for Televisions:
Notes: (This is work in progress.)
· This is not an exhaustive list, only those reported to work by forum members.
· Your help is needed here in checking its accuracy, completing the sets listed, and in listing more sets.
· Test successful column: The TV worked with one or both DVI equipped players and it produced a satisfactory picture in at least one resolution. There may be many caveats attached to this functioning.
· 1x1 pixel mapping column: At least 1 player output resolution could be matched one to one with the fixed pixel TV native resolution. Doesn't apply to CRT televisions.
Televisions with DVI
Support
|
Manufacturer and Set |
AVS Links Esp. on DVI support |
TYPE |
DVI Inputs |
HDCP |
Test Successful? |
1x1 Pixel Mapping |
|
Samsung TXN3098WHF |
CRT |
Yes |
|
Yes - Br D1 |
N. A. |
|
|
Sony 34XBR800 |
|
CRT |
Yes |
Yes |
Yes - Br D1 Yes - S 931 |
N. A. |
|
|
|
|
|
|
|
|
|
|
FP – DLP1 |
Yes |
|
?? |
No |
|
|
FP – DLP1 |
Yes |
Yes |
Yes - Br D1 Yes - 931 |
No |
||
|
|
FP – DLP1 |
Yes |
|
Yes - Br D1 |
No |
|
|
|
FP – DLP1 |
Yes |
|
No - Br D1 |
No |
|
|
|
FP – DLP1 |
Yes |
|
No - Br D1 |
No |
|
|
|
|
|
|
|
|
|
|
|
FP – DLP2 |
Yes - 2 |
|
Yes - Br D1 |
Yes |
|
|
|
FP – DLP2 |
Yes |
Yes |
Yes - Br D1 No - S 931 |
Yes |
|
|
|
FP – DLP2 |
Yes |
|
Yes - Br D1 |
Yes |
|
|
|
FP – DLP2 |
Yes |
|
Yes - Br D1 |
Yes |
|
|
Toshiba Mt8 |
|
FP – DLP2 |
Yes |
Yes |
?? - Br D1 Yes - S 931 |
Yes |
|
|
|
|
|
|
|
|
|
|
|
FP - LCD |
Yes |
No |
Yes - Br D1 |
|
|
Panasonic
PT-L300U |
|
FP - LCD |
Yes |
|
No - Br D1 |
|
|
|
FP - LCD |
Yes |
No |
Yes - Br D1 |
No |
|
|
Sony HS10 |
|
FP - LCD |
Yes |
Yes |
Yes - Br D1 Yes - S 931 |
Yes |
|
|
FP - LCD |
Yes |
No |
Yes - Br D1 |
No |
|
|
|