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[jmone]

For HTPC users outputting over HDMI/DVI to an AV Receiver you may experience the following problems (I know I did!):
1) Crashes / Hangs / Stalls - If you switch your AV Receiver away from your HTPC while media is playing you may find you HTPC has stalled, crashed, frozen when you switch back.
2) Mysterious Changing Resolutions - You may find the HTPC's Windows Resolution tends to change back and forth from what you have set to default settings (like 800x600) if you boot up when the AV Receiver & TV are not on - or even switching the AV Receiver between your HTPC and other sources.

EDID (Extended display identification data) - Many (most) Video Cards in your PC are designed to read the EDID information sent over HDMI/DVI and adjust its Video & Audio settings accordingly.  This EDID information is transmitted from your TV & AV Receiver so your HTPC knows that these devices support specific Video Resolutions (eg 1080p/60hz) and Audio Formats (eg 5.1 PCM, DD, DTS etc).  More info at http://en.wikipedia.org/wiki/Extended_display_identification_data

"Lost" EDID Information - The issue in an AV Setup is that when you switch your AV Receiver away from your HTPC (or boot-up without your AV Receiver / TV on and selected to your HTPC) you Video Card loses the signal and thinks that there is no longer any Monitor or Audio device attached to your HDMI port.  What happens next seems to differ between chipsets but typical issues include the resolution changing to default settings (eg 800x600), default 2 ch sound, and if you were playing media at the time various crashes, hangs etc as the renderers fail.

Adding EDID Persistence - The problem can be solved if the HTPC can "ignore" the loss of the connection, or if the relevant EDID information can be continually sent to the HTPC.  Unfortunately it seems the later is the most viable option and needs to be provided by third party HW devices.  Such devices (eg Monoprice DVI Doctor, and Gefen DVI Detective / Detective Plus) exist but range in price and features.  I've purchased the DVI Detective Plus and it fixes these problems (note: make sure you get the latest firmware!).  These devices work by initially reading the transmitted EDID data from your AV equipment then continuing to broadcast them to your HTPC.  I have installed mine as AV Receiver <--> HDMI to DVI Cable <--> DVI Detective Plus <--> DVI to HDMI Cable <--> HTPC (please note: DVI and HDMI cables are interchangeable - you just need an adapter as the ability to send Audio over HDMI/DVI is due to with the chipsets on either end not the cable).  You can now switch back and forth and your HTPC never knows.

Thanks
Nathan

[newsposter]

You will also lose EDID info if you are using 'cheap' HDMI-DVI converter cables/adapters.

It's better to spend a few extra bucks on 'real' HDMI cables and switch boxes instead of going cheap and fighting problems along the way.

[benn600]

You can really simplify by using a computer with an HDMI output.  I do not experience any of these issues you describe with my Denon receiver and LG television.  I never notice resolution changes or locking up when switching between sources.

The only issue I have noticed is that when hooked up to the Denon, I don't see the Overscan correction feature on the video card configuration utility.  If going directly to the TV I see it and can correct overscan in small increments to get the perfect picture, going almost perfectly to the edge.  Too bad TVs can't be as precise as computer monitors.  With computer monitors it is 100% pixel perfect edge to edge all the time no exceptions...if set to the correct resolution and settings.

So I think you're troubling experience may be common to some extent but I definitely don't have these issues...and I have 8 HTPCs throughout the house, almost all of them are unique hardware configurations / television combos.

[achambers]

Hey all, I realize this is an ancient post, but it helped me understand what was going on between my receiver, htpc, and display.  I was very close to buying an 'hdmi detective' to push the edid so I no longer had to hard reboot.  I found something however that might help others.  I installed powerstrip on my htpc, and I set a hotkey to 'refresh the desktop'.  Now, if I switch my receiver off or to another input, and come back to no display, I push ctrl-alt-r and my display comes back. 

Hopefully that helps someone!
-Andrew

[Daydream]

Well since we're reviving this, my problem is different. 3 LCD displays + one HDMI link to my receiver that's connected to my TV (all on 2 ATI cards). If I switch the receiver to a different input, or if I turn the TV off all 3 LCD screens flicker 3 times before coming back to their senses. Is this what happens for everybody (that have a setup close to what I described)?

Too bad TVs can't be as precise as computer monitors.  With computer monitors it is 100% pixel perfect edge to edge all the time no exceptions...if set to the correct resolution and settings.

That's the 1:1 pixel mapping that's missing on many TVs, especially the 1080p first generations (my Sony doesn't have it). There was a list on AVSForum which set can do 1:1 mapping but I think it's just a fraction. I'm guessing the newer sets have this implemented. Anyways, another thing to check when you buy.