[Help] UHD, HEVC, and stuttering...

[spoRv]

Yesterday I tried to watch an HDR UHD demo, encoded in HEVC, and the video stuttered with MPC-HD and other players (but first decoded HDR properly).

My CPU is an Intel i7-4770 and the GPU is a GeForce GTX 760... yes, not the latest top tech, but I was sure they was good enough... I was wrong, it seems.

So, would a "simple" GPU upgrade solve the problem? Or I should upgrade to a better CPU? (not using my actual motherboard, I'm aware)
Or, I need both new CPU and GPU?

Becuase I'm thinkering the idea of upgrading to another brande new used PC... AMD Ryzen or ThreadRipper, perhaps?

[deleted user]

I tried to play a UHD Remux on a PC with i7-3930k and a GTX 1070. I tried MPC-HC, which played fluidly, but had no tone mapping. Then I tried VLC, which also has no tone mapping, but it stuttered a lot. Then I tried mpv, which *does* have tone mapping and it played well.

That PC used to have a GTX 760, but I don't 100% reliably recall whether I tested playing an UHD Remux on it.

I think the main thing is the GPU really, because of the GPU acceleration.

Look here: https://developer.nvidia.com/video-encod...ort-matrix

Look at the NVDEC (DEC means decode here) table.

As you can see, the GTX 760 does not have HEVC hardware decoding, but the 10x0 models do. (you have to click on the "for a complete list, blahblah" buttons)

Without hardware decoding, you have a very high load on the CPU. But, the player you use has to support the GPU decoding, or it will be slow anyway. (as I think happened with VLC on that computer)

[MrBrown]

I think it is an encoder problem. I have a PC that plays UHD BDs fine on PowerDVD, but MPC and VLC did not work properly.

[Chewtobacca]

For UHD, use madVR in concert with MPC.  I get smooth playback even on my relatively old rig.

[babouin]

I agree with Chewtobacca, in my experience madVR is the best way to play HDR on a PC. It can pass HDR to your display if your hardware supports it or convert it to SDR.
For HEVC, it is much easier to decode with an hardware decoder, I believe pretty much any gpu from the last two years or so can do it.
If you really have to decode it using your cpu, LAV filters gave me the best results last time I tried.

[spoRv]

Tried to select MadVR in the MPC-BE (both 32 and 64 bit) and it freeze the frame, and get wrong aspect ratio...
Strangely, "normal" MPC seems to work more fluidly (enhanced rendering), yet some stutters here and there... maybe it's due to the fact it's a 10bit, or HEVC, or both... well, AFAIK the GTX 760 can't display 10bit - and it has not hardware HEVC decoder, so... time to buy a new GPU? Probably!

P.S. when I tried to play the demo (just 1 minute long) with MadVR (frozen frame) PC decided to shut off... have to discover why, as it happens sometimes when it overload, but it SHOULD NOT act in this way, with a liquid cooling! It started (I think) after I have moved it... what did I do?!?

EDIT: it made it again - this time MadVR in PotPlayer... I wonder what's the problem, as, for example, encoding a big video in x264 for 8 hours didn't shut it off.

EDIT 2: checking the CPU temp, it raises up more than 25°C (over 62°C and counting) when I play that 10bit HEVC HDR UHD demo (in just few seconds), while, for example, an 8bit AVC SDR UHD at higher bitrate goes around "only" 53/55°C - with peaks around 59°C... dunno... fans? CPU cooling?

[Feallan]

Your GPU doesn't have hardware decoding for HEVC. Hardware decoder is a dedicated chip (or a section of a chip) which has a single purpose - decoding a source using a particular algorithm. The chip is optimized for this single task, and can do it very efficiently. Without such chip, your CPU has to do all the work, and from the looks of it, it's simply not fast enough. You have a hardware decoder for AVC, that's why your PC is not even breaking a sweat. I don't know what CPUs are good enough for HEVC playback, but at higher bitrates I'm guessing only the top tier ones.

62C is not a high temperature at all, leave it running and check the max. Unless you'd get like 90+, you're good on that front.

[deleted user]

What do you mean by shut off, spoRv? Reboot? Or completely off? If it's completely off, could it be that your power supply isn't strong enough for some reason?

Other than that, it could be either a software or hardware problem (duh). My other PC used to have regular crashes/bluescreens and the only thing that helped in the end was to reduce the timing (frequency) of the RAM to below what it's actually classified for. Guess I got some bad sample. But was too lazy to send it back or anything, so I just underclocked it and it worked fine since then.

So, all I can think of concretely is to run a proper RAM test to at least cover this one base and maybe exclude it from the possible suspects.

Of course it could likely be a gazillion other things, but you have to start somewhere.

Also, you mentioned it happens during overheating. Is there any particular examples you can give of when it happened?

[spoRv]

@Feallan: I'd need at leastba GTX 1030 to get HEVC decoding. Now I know it!

@TomArrow: it just shut off and restart; it never did it before, since few weeks ago when I moved the PC. It "should" be overheating. Now, got to find out the cause:
- liquid cooling not working? But idle temp is around 30°C
- CPU dissipator dislodged during the move? Maybe
- thermal paste to be reapplied? Hardly, but possible
- air not entering? It is in a quite open place, room temp is not high either
- dust inside the case? Sure, but not so much... could it be the cause?

[deleted user]

Well, if the temperature sensor shows 30 degrees, I doubt that's the problem, but yeah in general it's possible of course. But I've often moved my PC, for example to friends for LAN parties etc., never had such problems.

Dust would only play into the heat issue (unless some got inbetween some connectors, but that's unlikely I think). But ofc it can't hurt to de-dust the computer and re-insert GPU, RAM etc.. (it's not much work, unlike CPU)

Really what I think would help is if you could identify or remember the specific things that trigger this to happen, that could help narrow it down. Did it ever happen during encoding too? When else? Also, check your Windows Event Log, the shutdown might be in there, as well as indicators of why it happened.

P.S. You could try posting a thread here https://www.reddit.com/r/techsupport/ and see if they can help you out. They certainly know more than me and likely get cases like that often.