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HDMI audio and DVI

V

venm11

2[H]4U
Joined
Oct 6, 2004
Messages
2,236
I'm curious as to why digital audio isn't [generally?] supported through DVI-D, such that an HDMI adapter can be used without a separate line for audio.

The thing is, DVI and HDMI are just different connectors; all the tranceivers are still the same. The audio is simply a separate data stream within that conduit. So why is implementing an audio stream not simply a driver issue? Many other stream-oriented changes have been made in drivers/firmware.
 
DVI is much older than HDMI, and back in the mid-90's, no one really had monitors that could output audio, if they did, it was using the 3.5mm audio jack.

Also, DVI was a huge luxury back in the 90's and early 2000's, and it wasn't until about 2004/5 that it really started becoming popular (and affordable).

HDMI wasn't even released until 2003, so the though of having video+digital audio go through one cable (DVI) wasn't really a thought back then.

So DVI was never intended to have audio included, even though it is capable of it now.

Also, you need to have physical hardware to produce the digital audio. If you don't have a built-in sound processor in the video card (AMD does this), then you need to have a pass-through cable which connects the audio stream on your video card to your sound card/integrated (NVIDIA does this).

and no, many stream-oriented changes have not been made through drivers/firmware. There has to be a hardware layer in order for the sound to be processed, whether it be a processor or a simple cable.


EDIT: HDMI is also much higher quality than DVI as it can support much higher bandwidth and resolutions (assuming the monitor can support it).
 
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I output sound from my GTX 480 via the DVI port into my Denon AVR-1910. The other end of the cable is HDMI, but the end that goes into the Video card is DVI. I do 1080/60p and 6 channel Lossless audio without a problem. This is also over a 25 foot cable, but the cable is rated for high-speed and is very large (22ga).

So sound can definitely work over DVI.

I'm not to sure about DVI being worse because I know that for a 30" monitor at 2560x1600 you can only use dual-link DVI to send the signal. HDMI is never supported for those resolutions. Though I also know that HDMI can now transmit 4K x 2K HDTV. Though that's only for HDMI 1.4 of which there is no DVI equivalent.


They both seem pretty capable to me and it just depends on the hardware and software at either end.
 
SirMaster said:
I'm not to sure about DVI being worse because I know that for a 30" monitor at 2560x1600 you can only use dual-link DVI to send the signal. HDMI is never supported for those resolutions. Though I also know that HDMI can now transmit 4K x 2K HDTV. Though that's only for HDMI 1.4 of which there is no DVI equivalent.
Click to expand...

HDMI is capable, it just has to be a 1.4a cable as far as I'm aware. You are right, it can support 4kX2k resolutions, DVI can output up to 2560x1600. Of course the video card has to be capable of those resolutions that go beyond XHD as well.
 
DVI has enough bandwidth for 1080p and 7.1 sound given the pins. But DVI is old and and was not originally built to deliver sound. Also it has older equipment standards to worry about when being updated. Plus, pins can get bend and DVI is a little large. Thus, there is HDMI which is smaller without protruding pins, and can be updated without worry about ancient equipment.
 
Red Falcon said:
DVI is much older than HDMI, and back in the mid-90's, no one really had monitors that could output audio, if they did, it was using the 3.5mm audio jack.

Also, DVI was a huge luxury back in the 90's and early 2000's, and it wasn't until about 2004/5 that it really started becoming popular (and affordable).

HDMI wasn't even released until 2003, so the though of having video+digital audio go through one cable (DVI) wasn't really a thought back then.

So DVI was never intended to have audio included, even though it is capable of it now.

Also, you need to have physical hardware to produce the digital audio. If you don't have a built-in sound processor in the video card (AMD does this), then you need to have a pass-through cable which connects the audio stream on your video card to your sound card/integrated (NVIDIA does this).

and no, many stream-oriented changes have not been made through drivers/firmware. There has to be a hardware layer in order for the sound to be processed, whether it be a processor or a simple cable.


EDIT: HDMI is also much higher quality than DVI as it can support much higher bandwidth and resolutions (assuming the monitor can support it).
Click to expand...

DVI was intended to carry different kinds of data, hence the provisions for packet type. Whether or not it was intended to carry sound is arbitrary, because the standard was designed to support expansion, and such an approach is commonplace and responsible everywhere in EE. The standard supported it, so the designs supported it, and the standard and/or actual designs were licensed by chip and hardware mfrs. That doesn't mean that many designs weren't integrated for economic reasons, but considering that HDMI was in development long before the mass proliferation of DVI, the need for electronics supporting DVI to carry sound and other non-video streams would have been well-known. Moreover, in order to have a reliable, mature design to support it when the market demanded it, supporting designs would have been in place long before that.

So one question is at what point the GX card manufacturers had the degree of programmability required to implement it, but another is when they actually programmed the thing to do it. There's likely a large gap there. And there's the motivation of them to update drivers for earlier cards to pass audio streams when they can sell a new card with the feature in place - not much.

So I don't think that audio support was a sudden thing, so there must be some cards that could, or do support it, and I'm asking which ones and why.
 
The last reason is the DVI group disbanded sometime ago, while the HDMI group is still around. No more official spec changes.
 
OK, I'm confused. Why are we pumping audio to the monitor, through the HDMI?
Is the audio now coming from the monitor to the speaker system? What if you already have a high end audio card? Or do you even need one with audio coming from the new generation video cards with HDMI output.

Sorry, but obviously confused. Thanks!
 
keithallenlaw said:
OK, I'm confused. Why are we pumping audio to the monitor, through the HDMI?
Is the audio now coming from the monitor to the speaker system? What if you already have a high end audio card? Or do you even need one with audio coming from the new generation video cards with HDMI output.

Sorry, but obviously confused. Thanks!
Click to expand...

Define "high-end" audio card. The only thing those cards can do that integrated can't is hardware acceleration (which doesn't matter at this point with quad-core CPUs) and EAX 5.0 for games, which can still be emulated well with integrated.

As for HDMI, it can support 7.1 digital audio through the cable. Why would I use a seperate SPDIF cable and a DVI cable when I can use HDMI and get both in one cable? The only higher grade audio that is 24-bit (HDMI does 20-bit with digital SPDIF) is fibre optic.

Also, HDMI supports MUCH higher resolutions and bandwidth than DVI could ever hope to achieve. I'm not saying DVI is bad or anything, but it is becoming a dated standard. This is why HDMI 1.4a and Display Port 1.1 are becoming more popular. Also, Display Port has and awesome connector with the clip so it can't be pulled out and is so much easier to attach that DVI is, imo.
 
OK. I'm with you. I just hope dell has the new HDMI input on their 2560x1600
30" monitors. Mine only has the HDMI connect, and I'm sure when this one goes
bad I'll want one one to replace it someday.
 
So...audio comes from the monitor since audio is contained in the HDMI cable that come from the newer generation VGA's?
 
Red Falcon said:
Also, you need to have physical hardware to produce the digital audio. If you don't have a built-in sound processor in the video card (AMD does this), then you need to have a pass-through cable which connects the audio stream on your video card to your sound card/integrated (NVIDIA does this).
Click to expand...

ok i'm confuse on this part as i've never run HDMI/never owned card that does this and i'm planning on building new PC so want to know what will be best for my use.

AMD :- they've build in sound processor (all you need is power cable and PCI express to get it working fully)

NVIDIA :- they don't have build in sound processor (you need audio cable connected to onboard audio connection to the video card)

am i understanding this right or is it other way around?
 
scbjmshpv said:
ok i'm confuse on this part as i've never run HDMI/never owned card that does this and i'm planning on building new PC so want to know what will be best for my use.

AMD :- they've build in sound processor (all you need is power cable and PCI express to get it working fully)

NVIDIA :- they don't have build in sound processor (you need audio cable connected to onboard audio connection to the video card)

am i understanding this right or is it other way around?
Click to expand...

Newer nVidia cards also have a built in sound proc, though only (generally) for the 400/500 series, and a few of the 200 series.

Bitstreaming of HD audio only exists in the lower range 400 series (GTX460 and below).
 
You can currently pass audio through DVI-D -> HDMI adapter with ATI cards but it is not a perfect solution as it is only 2 channel sound. You can have it encoded as surround though and have the receiver decode it (my current HTPC setup pretty much)
 
......so audio outputs now comes from the monitor, not from pc audio outs???
Why is sound going to a monitor via HDMI???
 
Audio can come from the monitor if you connected with HDMI. Some monitors give the option to send the audio received on hdmi back to a receiver (more common on TVs though)
 
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