HDMI Audio + monitor sleep = no more sound

bexamous

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Dec 12, 2005
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So how do you deal with this:

Sound goes through receiver via HDMI, and it works whether the TV connected to the receiver is on or off (eg I can hit power button to turn it off when I don' watn to watch tv). But when windows tells monitor to go to sleep sound turns off. So how do you listen to music if computer tells monitors to sleep?
 

jakeshields

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Jul 26, 2010
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I got tired of the hdmi dropouts and my personal solution was to run one hdmi port for audio, one hdmi/dvi to the monitor or TV directly so their operations are separate.
 

Sycraft

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Nov 9, 2006
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That is an HDMI limitation. HDMI can only transmit audio when video is also being transmitted. Well when a monitor goes to sleep, what that means is that your computer stopped transmitting video. Hence, the audio goes away too since there's no video to generate clock for it.

It is rather a pain in the ass, I'll agree. One solution is not have Windows turn your monitor, just send video all the time. You can still turn the monitor itself off, that it fine, your card just has to be transmitting video. Of course that means it won't sleep, you'll have to remember to power it off.

You could also get an HDMI signal generator, but they are expensive, like $250, and that only works if you are using a separate HDMI card that takes HDMI video in, and not just using your GPU.

Shitty design on HDMI's part, but unfortunately HDMI is all we got for lossless surround sound.
 

jakeshields

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That is an HDMI limitation. HDMI can only transmit audio when video is also being transmitted. Well when a monitor goes to sleep, what that means is that your computer stopped transmitting video. Hence, the audio goes away too since there's no video to generate clock for it.
I believe the computer is at fault here--Microsoft for not considering this with their sleep feature--and not the hdmi spec. Many hdmi based devices can playback audio with video switched off. For example, there are several models of blu ray players that have "pure audio" modes which you can enable with the remote, if you just want to listen to music rather than stare at the GUI on the TV.
 

Sycraft

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That is "pure marketing." Companies have tried to market special "pure" audio modes for a long time. My old, non-HDMI, Yamaha receiver has such a thing. Disengages processing, turns off all the displays and so on. Supposedly improves sound quality because there isn't so many electronics on. As a practical matter I can't hear the difference, and that is analogue.

Now HDMI is all digital so this "Less stuff for moar quality," is silly. It is 100% lossless at all times unless there's a transmission error. Then there's the fact that you have to have a video signal to have audio. Sorry, that is how HDMI works. There MUST be a video clock for audio to be transmitted. Look it up, audio is transmitted in between the video signal, not over its own wires. So a device can blank out the video, but it can't just not send a signal, it won't work.

Also, the way Windows is doing things is the VESA standard and far, FAR predates HDMI. Computer monitors are designed such that when they stop receiving a video signal, they go to sleep. That is the standard behaviour. As such that is how OSes and video cards do it. They shut down video to signal monitor sleep.

TVs don't work that way. If you shut down video to my TV, it just whines and pops up a GUI letting you know the input it is selected on. It keeps itself turned on. To get no GUI you'd need to transmit a blank video signal (or turn it off).

Sorry, but this is just the reality of the situation.
 

ragejg

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Dec 16, 2002
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I never had this happen until I just did a new build with Win7, but with the same graphics card (HD 5830). Now when I restart I gotta shut off and turn back on my TV to get sound working right. :(
 
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