[vegetable420]

Ok so my plasma has an HDMI port, but no DVI port. I've googled and found DVI->HDMI converter cables so am I to assume that HDMI inputs can understand a DVI signal as long as I get the converter to change the plug form factor?


Also, I've heard varying reports of the quality increase of Component vs. DVI. In theory DVI is better since it's digital so there's no degradation, but is this difference really noticable to the human eye? My HD receiver is currently using component cables that are shielded pretty well and HD channels look pretty darn crisp. Is it even worth monkeying around with the HDMI port?

 

[dsurkin]

Many people report better quality with DVI, compared with component (see the Yahoo newsgroup for Cablevision).


I purchased a DVI-HDMI cable from Pacific Cable, available in a variety of lengths. HDMI also carries digital audio, but DVI does not. You'll need to hook up regular audio cables with your DVI-HDMI cable. If your screen is a Panasonic, I know that the screen itself automatically detects if you have HDMI (with audio) or DVI to HDMI (requiring separate audio).

 

[rogo]

I don't mean to call out the original poster here, but there has been an increase in threads lately that ask a question that has been answered a good 1,000 times.


In this case, DVI and HDMI and whether they are compatible.


Please give the Search button a try now and then. Use the slowest search option if you don't get good results initially.


Dean did answer the question, though: They are completely compatible, save for the fact that only HDMI carries audio.

 

[vegetable420]

Sorry rogo. I actually did try searching for past posts without much luck (searched for "hdmi dvi", "hdmi", etc), but I didn't find much. In fact I usually can't seem to find specific answers very easily with the search. This forum is full of great info, but you usually only find it if you happen to be reading a thread in it's entirety. I googled this too and couldn't find an explicit, definitive answer (I found mostly propaganda about how HDMI is the future of digital television).


Anyway, I'll try harder next time, but I did make an attempt to figure this out before posting.

 

[Ross in Toronto]

There is a possible video incompatability that may become more apparent now that Pio is coming out with a 5 billion colour panel (see related thread). I believe the HDMI standard supports 12 bits per colour per pixel (36 bits total RGB), whereas DVI supports 8 bits per colour max.


My Pio 1110HD panel is 10 bit, so technically the DVI standard shouldn't be able to use all of its colours. There have been some other threads on this issue, too, especially because the cable that connects the panel to it media box *looks* like a DVI cable.


A DVI output to HDMI input should always work because the HDMI has more colour space "room". Going the other way (i.e., an HDMI out player like the Pio 59Avi into a DVI input display) may not always work... I don't know.


Ross

 

[rogo]

No need to apologize; that wasn't my point.


I just wanted to remind people that a basic question is likely to have been answered.


And, in general, it's good to search for information on one's own and then -- certainly -- ask any pertinent questions.


I got 463 hits here on HDMI DVI as a search using the Crawler setting. I got a lot of useful hits on Google, too. But anyway... We need a better FAQ here that we can point people too. That's our problem.


Anyway, Ross, it will always work >>both

 

[Ross in Toronto]

Mark,


If DVI HDMI works in both directions, how is the difference in bits per colour resolved? Am I mistaken the DVI standard is 8 bits per colour / 24 bits per pixel and HDMI is 12 bits per colour / 36 bits per pixel?


Thanks,

Ross

 

[PooperScooper]

DVDs and HDTV are still only being encoded with with 8 bits each for Red, Green, and Blue (at least the output of the MPEG decoder is RGB 4:4:4 for DVDs and I'm pretty sure for HDTV MPEG decoders) which is the only standard DVI supports. The higher color depths of HDMI is YCbCr (4:2:2 and 4:4:4) which very few devices accept (or generate). HDMI devices detect DVI on the other end and will automatically go into "DVI mode" - RGB 4:4:4 only. HDMI is really just a "superset" of DVI - data is transported the exact same way using TMDS.


larry

 

[Joe Murphy Jr]

Actually, the MPEG decoder outputs YCbCr, not RGB. For DVI transmission, this is converted to digital RGB. HDMI can transmit YCbCr or digital RGB. HDMI can support up to 12-bit color.


rogo

Speaking of a FAQ for digital video, why don't you ask Stacey Spears (MS, WidescreenReview), Greg Rogers (WidescreenReview), Dale Adams (DVDO), Keith Jack (Sigma Designs), Guy Kuo (Ovation Software) or all of the above to help out with a FAQ page. With input from these guys, all questions would be answered in quadruplicate, if not more.

 

[a.macree]

Quote:

Originally posted by vegetable420 Sorry rogo. I actually did try searching for past posts without much luck (searched for "hdmi dvi", "hdmi", etc), but I didn't find much. In fact I usually can't seem to find specific answers very easily with the search. This forum is full of great info, but you usually only find it if you happen to be reading a thread in it's entirety. I googled this too and couldn't find an explicit, definitive answer (I found mostly propaganda about how HDMI is the future of digital television)....

Hey vegetable:

Join the club. I feel your pain. The only way I finally got any useful, prompt, intelligent answers on my RGB-vs-VGA-vs-Component-vs-DVI-vs-What's the Difference? questions was from an AVS postee, couple months ago:

www.free-definition.com


O Man! Nirvana!

FWIW,

AMc

 

[BruZZi]

Quote:

Originally posted by Joe Murphy Jr rogo Speaking of a FAQ for digital video, why don't you ask Stacey Spears (MS, WidescreenReview), Greg Rogers (WidescreenReview), Dale Adams (DVDO), Keith Jack (Sigma Designs), Guy Kuo (Ovation Software) or all of the above to help out with a FAQ page. With input from these guys, all questions would be answered in quadruplicate, if not more.

"The Dream Team"

 

[Ross in Toronto]

Now its starting to make sense.


My Pioneer 59Avi DVD player, under "HDMI settings" has both an RGB and a "direct" mode. I suspect the direct mode is YCbCr, and therefore has more colour space to work with. It certainly looks better than RGB.


Good point, Larry, about the encoding. If almost all material is 8-bit encoded, then we really haven't taken advantage of the additional colour space on 10-bit panels...

 

[Ross in Toronto]

...I may have contradicted myself in the post above... if YCbCr has more colour space, but all the material is 8-bit then why would YCbCr look better than RGB...?

 

[melechmet]

Maybe another FAQ (or a series of them about connectors, cables etc.) should be created and cross referenced about the Forums; minimally with listing a good many links. My 2c: Boolian searching, ala Google and here on the Forum, is very contingent on phraseology, aside from the specific terminology. One almost needs to know the answer to ask the question. :]

 

[Joe Murphy Jr]

I think it's more like "The Head Spin" team. A FAQ from these guys is likely to have some noggins imploding from the inside out! On second thought, we may not be ready...



Ross

YCbCr is the format that's recorded on the DVD. If you use RGB out from the DVD player, a format conversion must be done. As with all conversions, there is room for error. It's also important to note the format that any processing will be done inside the display (YCbCr or RGB) and whether or not an outboard video processor is being used (YCbCr or RGB). Let's say, for example, that the plasma does all of its processing in the YCbCr format. The DVD player being used has a DVI output.


Here's what you would get with DVI:

(DVD encoding) YCbCr --> (player output) RGB --> (panel processing) YCbCr --> (panel display) RGB


vs one possibility with HDMI:

(DVD encoding) YCbCr --> (panel processing) YCbCr --> (panel display) RGB



And then there's my favorite, SDI...

 

[Ross in Toronto]

Joe,


Thanks. Makes sense. It may also explain the mystery of the DVI-ish cable connecting the Pio 910 / 1110HD's media receiver to the panel; the last step has to be done in RGB, which is likely taking place in the media receiver and fired up the DVI cable.


Ross