Picture glitching/pixelating

[Antelope]

Long time user of NPVR, it's been excellent, trouble free for years.  

I have an ageing Windows HTPC, an ASRock Vision 3D.  It's been a faithful servant for many years.  Through it I run a Hauppauge Freeview HD USB tuner (PCTV 292e) & a Hauppauge Freesat HD USB tuner (WinTV Nova S2).  Both worked absolutely fine until late August when the picture on both turners started glitching/pixellating for both live TV & recordings.  One day recordings were fine, after that new recordings are unwatchable.  Live TV is unwatchable.

The same issue manifests on both NextPVR v4 & v5.  It is NOT a signal issue and I do not believe this is an issue with NextPVR (tested on a laptop & had no issues at all) but would like to appeal to you good people for any help please.

The ASRock HTPC has an Nvidia GeForce 425M graphics card.  I've done a full reinstall of Windows & noticed when reinstalling the manufacturer provided drivers for the onboard Intel graphics are now obsolete for Windows 10 so for graphics it is running only the Nvidia GeForce graphics card.  

Whilst testing NextPVR on a Windows 10 laptop there were no picture glitching issues whatsoever.

Checking the Task Manager Performance Manager on the laptop whilst running NextPVR revealed it was only using its onboard graphics card - the Nvidia GPU on the laptop was not being used at all.

I'm wondering whether the ASRock Nvidia card is struggling with decoding the signal?  On the ASRock HTPC, checking Task Manager Performance Manager whilst running NPVR, the GPU is only at about 30% load but I wonder whether the Intel onboard graphics chip (which it can no longer use) is just more suited to the job of decoding the signal?

Any insight gratefully received.  It's strange how both tuners worked fine for years & both now have the same picture issue at the same time. The ASRock came with Windows 7 but has been running Windows 10 pretty much since the upgrade became available & NextPVR has worked fine until last month.  I'd rather not replace the ASRock unless I have to so this is the last throw of the dice! Thanks.

PS In case of questions, what I've tried:

1. Removing all Windows updates beyond the glitch date
   
2. Uninstalling/reinstalling both tuners
   
3. Delete both tuners from NextPVR to start from fresh (did not re-use my existing profile, did not import channels in order to rule out any gremlins here)
   
4. Uninstall/Reinstall NextPVR
   
5. Plugging the coaxial directly into TV (ruling out any potential issues with the cabling junction splitter - it's not a signal issue either, perfect picture when testing on the laptop)
   
6. Updating the decoders used by NextPVR (I've always used LAV decoder. Updating LAV decoder didn't help nor did switching to ffdshow)
   
7. Full reinstall of Windows
   
8. Blocked the fresh installation of Windows from updating to rule out a rogue update
   
9. Tried watching live TV via NextPVR using multiple browsers, same issue
   
10. Updated Windows so that it matched the version on the laptop.  Made no difference
    

[mvallevand]

I am confused by one statement "Tried watching via multiple browsers, same issue" are you talking web or NextPVR.exe playback?

Martin

[Antelope]

I am confused by one statement "Tried watching via multiple browsers, same issue"  are you talking web or NextPVR.exe playback?

Martin

I normally use NextPVR.exe for watching live TV.  During testing to try to resolve my issue I also tried via web on both v4 & v5 using Brave, Edge etc but all displayed picture glitching through the browser.  Thanks

[mvallevand]

Focusing on NextPVR.exe how is it?

Martin

[Antelope]

Focusing on NextPVR.exe how is it? 

Martin

The picture & sound glitch immediately.  I've attached an image link:

https://imgur.com/maGCmkK

Thanks

[mvallevand]

When you do the test on Win 10 laptop is it the same coax and location?

Martin

[Antelope]

When you do the test on Win 10 laptop is it the same coax and location?

Martin

Yes, I set the laptop next to the ASRock HTPC & switched cables from ASRock to laptop.  This is how I know it isn't a signal problem or an issue with NextPVR (to be sure, during tests I set up NextPVR from scratch on both ASRock & laptop)

Regards to the setup, the only difference I can see between the ASRock HTPC & the laptop is that the ASRock is no longer using the onboard graphics chip, only its Nvidia GPU, whereas Task Manager Performance Manager showed that when playing live TV the laptop is using only its onboard graphics chip, not it's Nvidia GPU.  This may be a "red herring" but as I tried everything I can think of it made me suspicious.   I can't think of a reason why both tuners would work on the ASRock for years on Win 10 then suddenly last month both tuners glitch.

Thanks for taking the time to look at this.

[sub]

If you do a recording, and play that recording in another player, do you see the same issues?

(this helps us know if it's related to capture or playback side of live tv)

[Antelope]

Yes, recordings show glitching throughout in VLC. They would also glitch in Kodi. Live TV also glitches through Kodi (using NextPVR backend).

[sub]

If the problem is present in the file that has been recorded, then it's almost certainly related to signal. Another possible candidate is driver compatibility issues with your machine. Less likely, but still a possibility, disk issues.