24p flawed with Nvidia GPUs?

[Xan]

For the past half year I've been trying to get this to work and I'm always getting reproducible ~7-10 second bouts of stutter every minute or so, no matter the video material in question. I'm using a GTX 660 with newest drivers, 1080p/23 Hz set in the driver for secondary display. TV is a Samsung H4500 plasma which does support 24p and also has a "Cinema Smooth" option for 96 Hz playback. I'm using VLC x64 as video player and tried increasing buffer size, enabling/disabling acceleration, and various other options. I've read it's possible to work around the issue by using Reclock to speed up the video to 25 Hz and output 50 Hz but this really seems like a stupid workaround for something that should work out of the box in 2015 in my opinion.

I've read reports of older integrated Intel GPUs being unable to output proper 24p and statements that Nvidia GPUs should be fine, but my experiences certainly contradict this. Anyone have any experience with this and/or can vouch for AMD GPUs working properly here?

[Thomago]

This isn't about Nvidia or Intel or AMD GPUs, but about the way PCs synchronize audio and video (by leaving audio untouched an introducing stutter to the video). Without ReClock (which resamples the audio) you won't be able to get perfectly smooth video playback. However, afaik ReClock doesn't work with VLC anyway.

[Fudoh]

In addition the alternative approach (syncing the output to the video material) never fully works on software based players solutions (e.g. a PC running windows), which makes all the interframe creation modes on TVs pretty much useless unless used with a hardware based media player.

[Xan]

OK, thanks for the clarification. This is pretty frustrating and I'm not sure why this seems to go largely unnoticed by many people. Time to invest in a hardware media player then...

[Fudoh]

the whole concept of 24p is still too complicated to most users. I assume most will just output everything at 60Hz and be done with it.

And honestly even the professional sites don't do much good by downplaying such flaws. AVForums UK recently reviewed an Android based media player (can't remember which one), mentioned features after features and eventually stated that it has a bugged 24p playback with regular stutter. AND THEY STILL GAVE IT A 07/10. Unless this stops and players like these get a 00/10 (or a 01/10 since they can still show pictures) I don't see this getting any better.

[blizzz]

This isn't about Nvidia or Intel or AMD GPUs.

That's not correct. NVidia GPUs are not able to output at 23.976 Hz. As far as I can tell that's still a problem with the most recent GPUs. At least my GTX 750 Ti and GTX 970 can't hit 23.976 Hz and instead output at 23.972 Hz. AMD cards have been better in this regard for quite some time and were therefore the better choice for HTPCs. Intel integrated graphics were for the longest time only capable of outputing at 23.972 Hz, but with the changes they made for the Haswell generation they're pretty much bang on 23.976 Hz now. My HPTC with i3-4130 can show 23.976p content for hours without any hickup.

One solution for NVidia cards is, as peviously mentioned, ReClock. You can get a nice setup with MPC-HC, madVR and ReClock and either slow down the audio to match 23.972 Hz or speed it up to 24.000 Hz which should run fine on most GPUs.

This is pretty frustrating and I'm not sure why this seems to go largely unnoticed by many people.

It hasn't been unnoticed. This is a long criticized flaw in NVidia cards and in Intel's Ivy Bridge it was referred to as the 24p bug.

[Thomago]

the whole concept of 24p is still too complicated to most users.

Yeah, people are mostly ignorant. Just take games as an example: Bazillions of PC games use Bink-compressed cutscenes and for reasons I don't know Bink's own playback solution (the in-game one) is extremely prone to stutter. I've tried to find a remedy for that for years, thinking it's my system's fault, but no - it's just Bink that sucks. And nobody seems to care, you hardly even find this problem discussed.

That's not correct. NVidia GPUs are not able to output at 23.976 Hz.

I didn't hear about this before but the thing is: It doesn't matter. Even if the refresh rate matched up perfectly you would eventually see stuttering.

[blizzz]

Yes, it will stutter eventually. But if it runs fine for 3 hours then it's not an issue.

[Xan]

the whole concept of 24p is still too complicated to most users. I assume most will just output everything at 60Hz and be done with it.

And honestly even the professional sites don't do much good by downplaying such flaws. AVForums UK recently reviewed an Android based media player (can't remember which one), mentioned features after features and eventually stated that it has a bugged 24p playback with regular stutter. AND THEY STILL GAVE IT A 07/10. Unless this stops and players like these get a 00/10 (or a 01/10 since they can still show pictures) I don't see this getting any better.

Playing it back in 60 Hz is actually better than what I'm getting here to be honest, as the motion judder is at least constant there. When you get nearly a minute of smooth playback and then 10 seconds of stuttery mess any immersion goes out the window.

I also just remembered that the TV has an own media player so that's what I'll try for the time being. It seems to work OK from a quick test, although several options like Cinema Smooth are greyed out.

@blizzz: this source states that you get a dropped frame every 4 minutes with Ivy Bridge and every 6 hours with Haswell, neither of which sound like a big deal at all.

[blizzz]

Maybe I misunderstood the issue. I haven't seen continuous stutter for several seconds on any PC I've used.

[Guspaz]

Just use MPC-HC with MadVR and Smooth Motion enabled. It uses frame blending to smooth out the judder, and the closer you can get your video output to match that of the video framerate, the less it will need to blend. Personally, I don't even bother with anything but 60Hz anymore, because I can't see any ghosting with it enabled, and the judder is gone, so it's simply good enough.

[cyborc]

when I use mpc+madvr+reclock on a gtx 970, outputting 24hz, the frame drop/repeat estimator is usually around 15 hours upwards to 1 day. I can't think of any movies that are that long This solution works great for me.

[BuckoA51]

This and a myriad of other annoying glitches and crap is why I'll never go HTPC again as long as I live. Friends don't let friends build HTPCs, they invariably just suck balls one way or another.