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redger
02-28-11, 05:42 AM
Is it possible to send audio over the HDMI and DVI outputs simultaneously ? On my Zotac GT430 ? nice card, for this application I was hoping to send audio to an LCD TV (at 108060p) and a receiver (which is capable of 1080i only but can read HDMI signals)

Is it possible to send audio over the DVI link at all ?? If so, do I need any special cables or adapters ?

I can get HDMI audio to work without problems ... but cannot find a way to send audio over DVI. Not sure if it's just me or a hardware limitation

thanks for your advice

tweaked
02-28-11, 06:23 PM
You shouldn't be able to send Audio over DVI.

redger
02-28-11, 06:59 PM
A partial answer to my previous question -

Audio will be sent to BOTH HDMI and DVI when -
- Two "screens" are connected from the graphics cards perspective (one may actually be a receiver)
- The screens are cloned
- Digital audio over HDMI is enabled (in linux ALSA digital controls must all (? 4) be enabled)

In my case, there is an additional constraint -
- HDMI must be connected to the receiver
- DVI connected to the TV

Under these conditions there is sound on both the DVI and HDMI cables. Both the TV and the receiver play the audio.

There may be something about my setup since I'm in a PAL country. The receiver wants a 50hz signal (interlaced, as it's an older receiver which cannot process progressive 1080/60p) whereas the TV's native refresh rate is 60hz and it can process 1080/60p.

So for the GT430 there is support for audio over DVI ... and simultaneous HDMI and DVI audio

If anyone has additional insight I'd be grateful

JasonPC
02-28-11, 08:55 PM
Just because the card supports it that doesn't mean the TV does?

redger
03-01-11, 12:30 AM
sort of. In my case it appears that it's the receiver that doesn't want to support audio over DVI - the TV is working fine with it.

It looks like there are -
- interactions between the DVI and HDMI ports. Either both work or neither work
- interactions with the receiver which are different to those with the tv. Both support HDCP (and generally do so correctly), but for some reason the receiver rejects DVI based audio .. which is odd because in theory it should be indistinguishable from HDMI based audio (only the connector varies not the content or path).

It is worth noting that the DVI port is dual link - I can't see why that would make a difference, since I would expect the DVI-HDMI cable drops the additional wires. Who knows ......

tweaked
03-01-11, 10:13 AM
Audio over DVI is out of spec. Its interesting that the card sends the signal. That makes me wonder if the card is treating the DVI and HDMI ports as the same interface.

Even weirder that the TV accepts the signal. I would expect it to behave the same as the amp.