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View Full Version : Article on DVI/HDMI vs Component Cables



KvHagedorn
2nd March 2005, 00:33
Thought I might post this here for you guys who think you "need" to have an HDMI connection for a really good picture. I hear this sort of thing all day from tech-fad-chaser types, who insist upon HDMI. They are just being played for suckers.

http://forum.ecoustics.com/bbs/messages/34579/122868.html

VJ
2nd March 2005, 01:24
Interesting read... :up:


Jörg

Jammrock
2nd March 2005, 13:55
Very good read. This is why my local AV shopcarries RCA DLP TVs. You have the option to disable all the internal video converters and whatnot and use an external video processor and component video to get the best possible signal.

Though those new JVC HD-ILA displays are looking pretty tempting these days.

Liquid Snake
2nd March 2005, 21:16
So it's much like the digital SPDIF vs. analog RCA thing for audio? Meaning, use whichever sounds (looks) best.

xortam
3rd March 2005, 09:56
Originally posted by Jammrock
... This is why my local AV shopcarries RCA DLP TVs. You have the option to disable all the internal video converters and whatnot and use an external video processor and component video to get the best possible signal. ... I seem to recall that it was RCA that screwed up their DLP implementation (presumably by being cheap and using old components) and they always rescaled the DVI input even when it was fed a native 720p signal. Their second generation DLPs still had the same stupid implementation. I don't know if they've gotten around to correcting this stupidity yet or not.

xortam
3rd March 2005, 10:31
HDMI isn't typically for the A/V'phile because they want high quality audio and you're not going to get that from a TV (at least no one's bothered in trying to build such a thing yet). HDMI is nicer than DVI for routing because of supporting longer cable lengths and its smaller connector head (fishing through walls). Longer runs (like 1000' feet) are possible with FDDI based DVI or HDMI cables though they get quite expensive. You can also use repeaters to extend the lengths, at a cost. Then there's the whole copy protection issue you have to consider. One of the nice things about digital cables is that they're relatively inexpensive compared to component cables and are less bulky. My most critical viewing is straight digital anyway so I don't want any extra D/A conversions and I can handle any digital-digital transformation myself in my HTPC. I use a WS LCD (with a plethora of video inputs) for my TV viewing right now. Most of my analog viewing has already been digitized anyway either by my DVDR or the content provider (via BUD satellite TVRO or DVD and such).

KvHagedorn
4th March 2005, 10:38
There's no real point in having a cable technology that runs HD picture and sound if it won't run 100-200 feet. Typically you want that in whole-house distribution systems, but in this case, firewire does a much better job (on the video side at least). The only problem is no manufacturers support firewire because you can record the signal that comes down that wire. This was why back in the day movie studios could not own theaters, because of conflicted interest. The damned government is not doing its job nowadays though. Companies like Sony should not be able to control content AND decide the industry standard by which that content is distributed.

xortam
4th March 2005, 12:08
There's no real point in having a cable technology that runs HD picture and sound if it won't run 100-200 feet. ...Sure there is. I'm integrating HD into a legacy system which includes a 17 year old whole-house distribution system (modulated video over coax). I don't need HD elsewhere about the house at the moment and my only HD display is in the HT/living room.

I wont' be able to debate this much at the moment due to the new site move. See my post in SF (http://forums.murc.ws/showpost.php?p=526810&postcount=29).

xortam
6th March 2005, 10:16
Well, I'm suffering through the JS script prompts for now so I can pick this thread up again if you want to discuss this further.


There's no real point in having a cable technology that runs HD picture and sound if it won't run 100-200 feet. ...And again, why would a critical HT user want to route sound along their video path given the choice? Where are their speakers and amps?

KvHagedorn
6th March 2005, 12:45
I suppose an HD video modulator would work for whole house video and sound once we are all converted to HDTV, but it would be nice not to have to go through this up conversion/down conversion process within the confines of your home.

xortam
6th March 2005, 13:51
HD, ED, and SD TV will need to coexist for some time to come. Thereís still an overabundance of SD video (both old and new content) that we will want to watch as well as the higher res formats. SD video is problematic on HD displays due to resolution and aspect ratio mismatches so itís actually many times preferable to watch them on a SD display. I have a collection of SD LDs that I will still want to enjoy and DVDs are only ED. The new 1080p displays (such as the Qualia 006) can handle SD very well but are quite expensive and have very high-end processors for scaling and de-interlacing. One can always down-res new HD content and route it through traditional SD channels or simply capture the SD version of the same content (the major U.S. networks broadcast both SD and HD of some shows). HD seems only appropriate in the HT room for now mainly because HD isnít of much value unless you have a display large enough to allow you to resolve the definition at the appropriate viewing distance.

I have no compelling reason to route other than SD about the house right now since my HD viewing requires my HTPC and my 23Ē LCD which are in my HT/living room (new large HD display system coming soonô). Iíve routed the SD video through coax all these years but still utilized speaker wire for my more critical listening in the remotely located master bedroom (both headphones and quality speakers). The less critical listening elsewhere inside and outside the house utilize the coax for both modulated video and audio. I wanted to route A/V digitally back in í88 but the market wasnít ready for me.

Error correction can always be placed onto these new interfaces and DTV already utilizes FEC in the TS data for ATSC and QPSK via satellite. I would think that there are FEC capable devices that can be utilized for longer runs of DTV across DVI and/or HDMI.

Fluff
7th March 2005, 10:39
HD-SDI seems the best and the cables seem to be alot simpler / go along way .
But it's for 'professionals' such is life....

Wombat
7th March 2005, 12:24
I'm not impressed with this article. This paragraph here is quite misleading:
That might be true, were it not for the fact that digital signals are encoded in different ways and have to be converted, and that these signals have to be scaled and processed to be displayed. Consequently, there are always conversions going on, and these conversions aren't always easy going. "Digital to digital" conversion is no more a guarantee of signal quality than "digital to analog," and in practice may be substantially worse. Whether it's better or worse will depend upon the circuitry involved--and that is something which isn't usually practical to figure out. As a general rule, with consumer equipment, one simply doesn't know how signals are processed, and one doesn't know how that processing varies by input. Analog and digital inputs must either be scaled through separate circuits, or one must be converted to the other to use the same scaler. How is that done? In general, you won't find an answer to that anywhere in your instruction manual, and even if you did, it'd be hard to judge which is the better scaler without viewing the actual video output. It's fair to say, in general, that even in very high-end consumer gear, the quality of circuits for signal processing and scaling is quite variable.

Digital/digital "conversion" - which it's not, it would be a transform - is algorithmic in nature, and very different than something with analog involved.

Also, they talk about analog surviving long cord runs w/o signal boosting. Who cares if you boost a digital signal? No harm done, unlike analog.