dvi to hdmi adapter carries sound.

[bdub]

yeah, back a while it seemed there was some proprietary technology in those nvida cards... but now it seems it is just plain normal, as my brother's amd 6450 card does it easily with only the addition of a dvi/hdmi adapter (which I believe is quite common, it's not like it came with the video card he's using.
I know that videocards with hdmi built into them do put some devices into the sound controllers section of device manager, so that's no big deal... but to make audio come out a dvi port? that's something special, or so I thought.

[bdub]

found this thread which talks about audio being combined into the dvi port a little...
http://forums.stevehoffman.tv/threads/d ... mi.273139/
here's some of the dvi/audio references from the thread...

"Modern GPUs have their own built-in audio chip, output HDMI natively via an HDMI port and Windows 7 will automatically switch to said A/V output when a display is connected. They can also output via DVI with otherwise unused pins assigned to audio, which are then connected to the correct HDMI pins via an included DVI-to-HDMI adapter. "

"Audio is admittedly slightly less common but like I said, most modern GPUs will output audio over DVI but they have to be set up correctly and you have to use the special adapter that came with the graphics card (AMD and nVidia probably use different pins to do different things so you need the matching one for your card). Integrated graphics processors might be less likely to have this capability, I'm not sure."

"Further, audio does not ride on additional DVI pins, and does not interface with HDMI in this fashion. Audio in the HDMI spec occurs during video blanking, it doesn't reside on it's own pins or have it's own signal transmission, it is basically a subset of the video data."

so still unclear exactly how it works, but good to find more posts on the subject.

[Karlsweldt]

Some links about video blanking intervals..
http://en.wikipedia.org/wiki/Talk:Verti ... g_interval
http://www.ni.com/newsletter/51078/en/
While the blanking intervals occur frequently, their cycle time is short.. less than 10 ms.
Not sufficient to carry a high quality audio signal, in analog or digital.
Using the R-G-B leads for audio instead of video is likely the true design.

[rascard2007]

Looks similar to trasmiting internet signal trough the normal 110 V power lines