: FAQ - DVI/HDMI Information


57
2004-11-23, 05:05 PM
Although this (older) thread can still be useful with lots of DVI/HDMI information, the following link contains newer, HDMI Issue information.

http://www.digitalhome.ca/forum/showthread.php?t=71112


HDMI is basically DVI plus digital audio. Therefore most of what's said below is also applicable to HDMI.

DVI - A Practical Guide to DVI (http://dvi.baumannpaper.com/)

http://www.hometheaterhifi.com/volume_11_4/feature-dvi-hdmi-hdcp-connections-11-2004.html There are minor difference between HDMI/DVI

DVI Connector Information (http://www.ramelectronics.net/html/DVI_monitor_cables.html)

Sample DVI Cable Lengths and Prices (http://www.national-tech.com/catalog/dvivideocable.htm)

Canadian DVI Cable (http://www.ncix.com/products/index.php?sku=10893)

Another Canadian Supplier (http://www.infinitecables.com/)

Many computer stores sell DVI/HDMI cables for about $10-25. No need to go to FF, BB and buy Mon$ter for $100...

More places to buy cables (good reviews on monoprice)...

http://www.pacificcable.com/Picture_Page.asp?DataName=DS-21R

http://stores.*********/HDTV-Supply_W0QQcolZ2QQdirZ1QQdptZ0QQpZ2QQsclZallQQsotimedisplayZ 2QQtZkm

http://svideo.com/index.html

http://www.tigerdirect.ca/indexca.asp?

http://www.monoprice.com/home/index.asp

http://www.moregadgets.ca/catalog/index.php

http://digitalhomecanada.com/forum/showthread.php?t=31337 (99 cent HDMI)

Still more...

I'm not a DVI expert, but I've assembled the following information from various threads. I'll update as necessary.

Here?s a great link to a DVI overview and some DVI FAQs

http://www.ce.org/about_cea/cea_initiatives/downloads/dtv/DVI_Informational_Doc_1_04_02.pdf

http://www.datapro.net/techinfo/dvi_info.html


Some Comments on DVI

1. DVI is digital (sending information at over 1 Gb/sec. Component Video is analogue.

2. DVI/HDMI was NOT designed to provide superior picture quality to component video. They should really be considered as "equals" in terms of PQ. Any differences you see are likely due to differences in equipment or the way the various inputs are calibrated (or not calibrated) on your TV, not the connector.

See: http://www.tomsguide.com/us/2007/09/11/hdmi_vs_component/ (Thanks to Caatnap for the link)

3. DVI/HDMI may provide a superior picture when viewed on a fixed pixel display (like LCD, DLP, Plasma, LCoS) since these are digital displays, so the signal remains digital "all the way". CRT-based TVs are analogue, therefore a superior picture is less likely on HD inputs since the D/A conversion must take place somewhere in the chain.

4. TVs contain EDID, which the source device (e.g. STB) reads in order to determine the video formats the TV (sink) supports. There is nothing in the EDID that positively tells the source that the sink is TV or a recorder, etc.

5. So far, few A/V receivers have DVI/HDMI switching capability. Those that do are "flagship" receivers (very expensive). See additional comment regarding firmware at the end of this FAQ.

6. DVI/HDMI switches are typically quite expensive (>US$100).

7. DVI/HDMI cables may have a length limitation of about 50'.

8. DVI comes in two flavors: digital (DVI-D) or digital and analog (DVI-I). Computers tend to support DVI-I. STBs and DVD Players tend to support DVI-D.

9.HDMI is backward-compatible with DVI.

10. When connecting via DVI, it sometimes "disables" the TVs stretch modes since the TV thinks it's getting an HD signal. This can cause some problems and perhaps require a second connection... This issue is specific to the TV, the STB or the DVD player... Make sure the STB is set up properly and it'll usually work.


DVI as it relates to DVD players. (Some new DVD players have DVI outputs.

A . Some new DVD players have DVI outputs. These DVD players "upconvert" the DVD?s 480i signal to 720p or 1080i. This upconversion is done while in the digital domain, so this may provide a superior signal to any TV, regardless of whether it?s analogue or digital.

B Some DVD players that have DVI outputs have been reviewed as having quite weak PQ when using the component video outputs,. Therefore only buy one of these if you have a DVI equipped TV, or know that the DVD player has good component out quality.

C. Some people think that you cannot upconvert to 720P or 1080i using the component video cables. This is not the case as some DVD players have this feature, but see point "B".

Some HDMI comments:

- Many people have had difficulty in connecting HDMI outputs to DVI inputs on TVs. Make sure you have the appropriate connectors and that they are securely seated. Try it without any adaptors but with the appropraite cabling as the adaptors have caused some issues.

- Some TVs have HDMI inputs and digital audio outputs. If you run HDMI to your TV and run a digital audio connection to your A/V receiver "through" the TV, you will likely lose the DD5.1 signal. Better to run the digital audio connection directly to your A/V receiver from the STB.

- Some STBs only allow HDMI/DVI OR, component video. If you can't get your digital connection to work, be sure to disconnect your component video cables.

- I understand that many customer in the US who use HDMI are unable to get DD5.1 out of the digital audio ports - some sort of firmware issue...

- There have been a fair number of posts indicating that Toshiba HDTVs have more than their share of "handshake" issues with DVI/HDMI.

- I have heard of some problems with HDMI and DVI being caused by the connector not being well seated. Make sure you press it in very firmly, perhaps even pulling it out and reconnecting a couple of times to ensure that any "gunk" or "oxidation" is removed from the pins.

- There are some HDMI switching A/V Receivers on the market now, however, there have been some firmware issues in that signals from some devices have not been getting to the TV "through" the receiver (SA STBs for example).

More DVI/HDMI reading:

http://www.sanyo.com/lcd/resources/files/Sanyo_DVI_HDCPArticle_110904.pdf

If you have any comments, corrections or questions regarding this post, please send me a PM.