Very obscure HDMI issue, can someone help?

[Scoob]

Hi all,

This one has been vexing me, so here's a little history...

I bought a Hannspree 32" LCD TV back in 2007 for use as a TV Connected to my digibox and as a PC screen connected via VGA. Picture quality with VGA was fairly rubbish, as you'd expect, so I picked up a DVI to HDMI lead to run from my GTX 275 to the display. Worked brilliantly.

After a couple of years of steadfast service, that old GTX 275 was upgraded to a GTX 570 - a hand me down from my main gaming rig at the time. It was then I ran into this issue for the first time, due to the 570 supporting HDMI and audio over HDMI of course...

An issue in the Nvidia drivers means that if the 570 is connected via HDMI (or DVI to HDMI cable) to a TV, it will always force audio over HDMI. On the face of it, this doesn't sound a problem. However, firstly I use a discrete sound card for my audio, it has better quality for whatever reason. Secondly, when video and audio are pushed down HDMI picture quality is hugely degraded on my TV - akin to running a VGA cable ironically.

Back in 2009, when this issue first occurred, I got to the bottom of it, discovered the route cause and created a solution. That solution was creating a custom Monitor driver for my TV explicitly saying it does NOT support audio over HDMI - i.e. it's basically just a monitor. Applying this new driver and rebooting immediately saw audio going via my soundcard once more and the picture quality pin-sharp - really, it was a world of difference.

Fast forward to yesterday... This PC, still in use daily as a general internet / media PC still running Windows 7, had started to have a HDD issue on the system drive. Pending reallocations and the odd blue-screen when issues occurred. So, I took the opportunity to pop a spare SSD in the replace the faulty drive and popped W10 on the machine.

All went well, but I once again encountered the poor image quality and no sound from sound card issue again. Not a problem, I thought, I'll apply my custom Monitor driver once more, which I did. However, while the driver was accepted (after allowing unsigned drivers) it did NOT fix the issue like it did previously - the poor picture quality remained, and audio only worked via the GPU, my soundcard was ignored.

I re-downloaded updated versions of the free tools I used once before and created a brand new driver for my monitor, tweaking the appropriate settings and noticed that certain values were now different under W10, which was what I expected. However, upon loading this new driver and rebooting the issue remains.

So, I spent several hours yesterday trying to get to the bottom of this. I don't know why my Monitor Driver fix - which was so successful for YEARS under Windows 7 - is totally failing to work under Windows 10. The display is usable, just about, but picture quality is "out of sync VGA" levels making text blurry and affecting colours.

Now, I know I have what is basically now an ancient TV, and I'm sure newer models would likely just work, but this TV is still GREAT, well it was under Windows 7, and I don't want to replace it at this this time.

I'm posting here on the off chance anyone has experienced something similar and has a solution for me. The sad thing is that this is basically an Nvidia problem with them forcing audio over HDMI even if the audio driver component is uninstalled and GPU audio set to disabled. Before "Blocking" this via a monitor driver tweak worked brilliantly, but NV's seem to be ignoring device capabilities now, forcing HDMI audio when the device does not support it in the driver.

Edit: I have of course disabled all HDMI audio devices, ensured the soundcard is the default etc. etc. but none of this helps. Regardless of settings, I get NO sound from the soundcard, but retain the corrupted display caused by HDMI audio even when fully disabled.

Any help appreciated.

Cheers,

Scoob.

 

[Scoob]

So, the miracle that is the OC3D forum continues...

No sooner do I post about the issues that frustrated me until late last night, try again (creating a Monitor Driver) and this time...it works like a charm!

My tired brain must have gotten something wrong, though comparing the two drivers I created they look the same...maybe some whitespace issue in the raw data.

Anyway, my nine year old TV is once again crisp and sharp, and using the far superior Soundcard in my system rather than HDMI. This old TV, not being constrained by the need to be thin, has some very good speakers fitted, so the better audio quality is most welcome. Also gone are the glitches and chopped windows sounds. Nice.

If anyone needs assistance with a similar issue, reply here and/or PM me.

Cheers,

Scoob.

 

[barnsley]

Sounds to me that Windows 10 might be using a generic audio over HDMI driver when it first detects the hdmi output, and that the driver for the soundcard is being overridden. Even if it is the Default audio device, Windows will ignore it if it doesn't see it on startup (in my case, it was because the USB wasn't supplying power until the system had booted past the initial check on startup).

If you've not tried it, I'd suggest disabling plug and play to see if Windows is being 'helpful'. Not ideal but worth to see if that is the case. You can disable it for specific devices/device IDs on W10 pro, just not home.

-edit- Typed before you had posted your reply. Whoops!

 

[Scoob]

Sounds to me that Windows 10 might be using a generic audio over HDMI driver when it first detects the hdmi output, and that the driver for the soundcard is being overridden. Even if it is the Default audio device, Windows will ignore it if it doesn't see it on startup (in my case, it was because the USB wasn't supplying power until the system had booted past the initial check on startup).

If you've not tried it, I'd suggest disabling plug and play to see if Windows is being 'helpful'. Not ideal but worth to see if that is the case. You can disable it for specific devices/device IDs on W10 pro, just not home.

-edit- Typed before you had posted your reply. Whoops!

Hey Barnsley,

No that's a good call, and something I did think of myself initially, though it turned out not to be the case

It does appear that the option to disable GPU Audio over HDMI in the NV Control Panel does nothing...well, worse than nothing really. Basically, when I just disabled HDMI Audio this way, sure, things went silent, but audio (even though silent) was still being transmitted down the HDMI cable, both corrupting the display and "blocking" audio from the sound card.

I'm really glad I got the Monitor driver working as only that telling the NV Drivers that "Sorry guv, I ain't got no speakers" stopped my GPU from buggering things up.

It does seem crazy how this has been an issue in NV drivers since the 180.x or something like that. I guess though that newer TV's just work and this was a problem only back when the tech was fairly new.

Sooo very happy that I don't need to replace my TV - because I would have if that was the only solution as the corrupted/blurred display was giving me severe eye strain as my eyes attempted to compensate for the blur.

Anyway, I do appreciate your response on this one, even though I'd already managed to sort it.

Cheers,

Scoob.