HDMI, DVI, component. Saw no picture quality difference. [Archive] - Audio & Video Forums

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Widowmaker
03-15-2005, 11:51 AM
Hey, everyone, it's been a long time since I've been here and it's good to be back.

Recently, I purchased a Sharp 26" LCD panel and switched to DIRECTV's HD service. The box gives me a choice of HDMI, DVI, or component to broadcast HD. I have it plugged up by HDMI (thankfully, I only paid $10 for the cable instead of the ridiculous prices that they're going for now) but as an experiment, I borrowed a DVI cable from work and used an old component cable to see if there really was any difference in picture quality.

Trust me, I looked hard and long and from my eyes, I just could not see any difference between an analog (component) versus a digital (HDMI, DVI) connection. Sure, HDMI's and DVI's original purpose was not to improve PQ but to protect content owners from piracy but it's very telling how salespeople or product literature all proclaim the vast difference between analog and digital connections. Perhaps they just want to sell more expensive HDMI and DVI cables, I don't know.

Is it just me or does anyone else not notice a difference between the various HD connections?

edtyct
03-15-2005, 12:44 PM
A vast difference would be overstating the case; no difference is often the case; and a slightly worse picture is sometimes the case. It all depends on execution. Theoretically, a digital connection offers the possibility of improved image quality whenever the signal will not have to endure D/A conversion. Automatically, a CRT would not qualify for this reward, since it by nature would have to convert digital to analog. Microdisplays like yours stand to benefit the most--as I said, theoretically. On a relatively small screen like yours, improvements in sharpness at this order of magnitude would be hard to see, anyway, even on test screens. Moreover, if a particular digital output/input isn't too good, and/or the component input/output is quite good, no difference might be evident. Another possible factor in your case is the degree of compression that broadcast HD has to undergo in order to fit all of the stations along the wire. That kind of leveling might work against much visible improvement.

Are you setting the tuner to 720p, which, I assume, i (#)s the Sharp's native vertical resolution, or 10 (#)80i? If DirectTV defaults to 1080i, the Sharp would have a little more difficulty scaling back to 720p, or 768p if that's what i (#)ts resolution is. The quality of deinterlacing and scaling, from different outputs, can have an effect on what you see.

I can tell you that on at least a 42" Sony LCD screen, the picture from a Sony HDP-DS975V DVD player looks better via HDMI than component, though component is not likely to disappoint anyone. Upconversion to 720p on the Sony DVD player refines the PQ even further. It simply does a better job of scaling than the Grand Wega does.

Ed

Widowmaker
03-15-2005, 01:22 PM
A vast difference would be overstating the case; no difference is often the case; and a slightly worse picture is sometimes the case. It all depends on execution. Theoretically, a digital connection offers the possibility of improved image quality whenever the signal will not have to endure D/A conversion. Automatically, a CRT would not qualify for this reward, since it by nature would have to convert digital to analog. Microdisplays like yours stand to benefit the most--as I said, theoretically. On a relatively small screen like yours, improvements in sharpness at this order of magnitude would be hard to see, anyway, even on test screens. Moreover, if a particular digital output/input isn't too good, and/or the component input/output is quite good, no difference might be evident. Another possible factor in your case is the degree of compression that broadcast HD has to undergo in order to fit all of the stations along the wire. That kind of leveling might work against much visible improvement.

Are you setting the tuner to 720p, which, I assume, i (#)s the Sharp's native vertical resolution, or 10 (#)80i? If DirectTV defaults to 1080i, the Sharp would have a little more difficulty scaling back to 720p, or 768p if that's what i (#)ts resolution is. The quality of deinterlacing and scaling, from different outputs, can have an effect on what you see.

I can tell you that on at least a 42" Sony LCD screen, the picture from a Sony HDP-DS975V DVD player looks better via HDMI than component, though component is not likely to disappoint anyone. Upconversion to 720p on the Sony DVD player refines the PQ even further. It simply does a better job of scaling than the Grand Wega does.

Ed

Hey, thanks for the reply. Yes, I am setting the box to output 720p (the Sharp's native resolution) and even with all my close staring, I still did not see an earth-shattering difference. I'm not saying there's no difference whatsoever, maybe if you plugged the box to some machine, it can detect differences caused by A/D conversion but what I'm saying is with my naked human eye (20/20, BTW), I couldn't see a change.

Also, I'm a little skeptical regarding those DVI/HDMI upconverting DVD players. I know that it's mathematically impossible to get true 720p or 1080i resolution from a current-gen DVD and I've read reviews of some of those players and the reviewers state that they prefer the picture on the component output instead of the digital output.

LEAFS264
03-15-2005, 01:28 PM
I would also like more info on this subject as i bought a HDMI 52" DLP fron Toshiba. And i need to know if i should spend the $$$ on Component or HDMI cable.


Jay.

edtyct
03-15-2005, 01:57 PM
Yeah, sometimes component looks better than HDMI/DVI, for reasons already stated, and others not stated (like color space problems, or the wrong IRE standard) but the theoretical reason for improvement still remains, and it is often confirmed. The Bravo D2 was the first DVD player that I recall to rate high marks for its digital output; other early players weren't so lucky, or so good.

It is mathematically impossible to turn 480p resolution into a resolution that is inherently 720p by extrapolating its own data. However, 480p upscaled to 720p is still 720p, in the same way that 480p automatically upscaled to the native resolution of your Sharp LCD is really 720p. It just suffers from the fact that it did not originate as 720p. The upconverting DVD player really isn't doing anything that an HD microdisplay doesn't do to an incoming SD or ED signal; it just has a chance to do it with a little more finesse and less complication, which in itself theoretically translates into an advantage. Until manufacturers master the technology, all we can do is check to see which set of inputs/outputs looks/tests better.

Ed

LEAFS264
03-15-2005, 02:08 PM
So, does that mean with my DLP i'm better off NOT using the HDMI because the T.V is 720p native and the Pioneer Elite 59avi player is upconverting the 480p to 1080i or 720p.



Jay

edtyct
03-15-2005, 02:21 PM
Jay, if the Pioneer upconverts to 720p, it's worth comparing the result to 480p from both component and HDMI. You are in an ideal situation. The TV is large enough for you to see differences, and its 720p native resolution is tailormade for 720 upconversion from a DVD player. First, via HDMI, it has no major conversion to analog along the signal path to create artifacts, and the TV itself has no need to do anything at all to the signal sent by the DVD player's HDMI output, since this output is already at 720p, which is the resolution that your TV scales everything to, anyway. If you send, for example 480p or 480i across from any of the DVD player's outputs, the TV will have to scale the signal to 720p just to show it. If you can accomplish this scaling before the stream hits the TV, you may well get a superior picture. I look forward to your report. By the way, I have no idea how good the Pioneer's 3:2 pulldown or video deinterlacing is relative to the Toshiba's. That could have an effect, too. But give the two sets of inputs/outputs a try, and see if your eyes notice anything.

Ed

LEAFS264
03-15-2005, 02:37 PM
A 14-bit, 216MHz video digital-to-analog converter (DAC) that delivers professional-quality video. This high-end DAC provides exceptionally clean images with very low noise.Three high-end

Burr-Brown Chipsets, for extraordinarily pure audio processing.


A Pixel Conversion IC that automatically increases the pixel count from progressive 480 x 720 to an amazing high-definition progressive 1280 x 720, or 1920 x 1080i. More pixels = better picture. This feature works on all material, whether video or film, and regardless of source (DVD, TV, cable, etc).


That was taken right from Pioneers website on the DV-59AVI so does that mean that it does upconvert the 480p to 720p before it gets to the DLP. And i would need to use HDMI to do it. Does the quallity of the HDMI cable make a difference?

edtyct
03-15-2005, 02:59 PM
I just went to have a quick look at the review of the Pioneer on the Ultimate AV site. It seems like a hell of a good one. Tom Norton says that on his review system, the HDMI trumped component. Anyway, yes, it converts to 720p before reaching the DLP. Many cables are overengineered to protect against various sorts of interference. If your run isn't more than 2 meters and doesn't have to negotiate an enormous tangle of wires and other sources of electrical noise, you don't have to buy a Monster HDMI cable. Take a look at Pacific Cable's site. Another dealer worth checking out is Lenexpo, which has an ebay store that sells cables at unbelievably low prices. I use one of their 2m DVI cables, costing about $13.00, which I checked vigorously against one of my Monsters, and it's every bit as capable. Ordinarily, you don't have to spend an arm and a leg on cables, but Ram, Pacific, and other sellers that advertise on audio/video sites make cables that should work perfectly.

Ed

LEAFS264
03-15-2005, 03:17 PM
Thanks for the advise.
Can't wait to get it all put together


Jay