[User 328513]

SOLVED: The problem was apparently that the proprietary Nvidia drivers can only sync to one display. Even though I switched my desktop from my PC to my TV (leaving my PC monitor to go to standby), Nvidia still wanted to sync to the PC monitor. By turning off the PC monitor while using the TV, Nvidia immediately jumps to syncing with the TV, and not the PC monitor. I could even turn off the PC monitor in the middle of watching a movie on my TV, and the stuttering would go away.

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I experience symptoms similar to 3:2 pulldown judder (regular stutters every 1-2 seconds) with 23.976 content even though my refresh rate is 24Hz (yes, my TV switches to 24Hz when the video starts). The TV may be using 23.97x for all I know. If the TV is really using 24.000Hz then sure, it won't be perfectly smooth, but there shouldn't be regular stutters every 1-2 seconds.

This is only a problem in Linux, it works fine in Windows (I'm dualbooting).

I've tried to solve this, but I'm stuck and can't figure it out.

Relevant info:
Linux Mint 17.3
Nvidia GTX980Ti, proprietary drivers
"Adjust display refresh rate" on
"Sync playback to display" on (but makes no visible difference whether on or off)

Please let me know how I can proceed in order to debug and fix this problem. I'll happily provide any other helpful info.

Update: This actually seems to happen with other media players too (on Linux). If I manually set the refresh rate to 24Hz and play the video with another player, it stutters in the same way. Still, I'd be immensely grateful for any help in finding out what could be wrong.

Update: Logs and info
Linux log: http://pastebin.com/DP9rdiMK
Linux log Kodi 17 alpha: http://pastebin.com/FRGHkUum
Windows log: http://pastebin.com/cp3N2ngH
Mediainfo: http://pastebin.com/MkDj2RmD
DISPLAY=:0 /usr/lib/kodi/kodi-xrandr http://pastebin.com/uhMYfqjk (HDMI-0 is my TV)

[fritsch]

A Debug Log will help us. Especially as nvidia has no real 24.0 modeline - a bug since years :-)

"Mint" <- with its nice compositor was not made for movie playback.

[fritsch]

And something else: We don't do a pulldown ... never.

[MrMC]

mediainfo might tell more, some content actually has 3:2 pulldown embedded in the time stamps.

[fritsch]

if it's in the PTS - then that's something else ...

[User 328513]

Linux log: http://pastebin.com/DP9rdiMK

Windows log: http://pastebin.com/cp3N2ngH

Mediainfo: http://pastebin.com/MkDj2RmD

And something else: We don't do a pulldown ... never.

Sorry, I don't really know the terminology or the technical details. The point I was trying to get across is this: I experience a visible stutter every 1-2 seconds. If I look at the codecinfo ("o" key) with "Sync playback to display" turned on, the info overlay shows that most of the stutters correspond to dropped/missed frames.

Let me know if I can be of any further help.

[fritsch]

09:00:27 T:140055557424896 DEBUG: OutputPicture - change configuration. 1920x1080. framerate: 23.98. format: VDPAU
09:00:27 T:140055557424896 NOTICE: Display resolution ADJUST : HDMI-0: 1920x1080 @ 23.97Hz (20) (weight: 0.000)

vs:

Frame rate : 23.976 fps

Now please provide:

DISPLAY=:0 /usr/lib/kodi/kodi-xrandr | pastebinit

[User 328513]

DISPLAY=:0 /usr/lib/kodi/kodi-xrandr
http://pastebin.com/uhMYfqjk (HDMI-0 is my TV)

[User 328513]

Let me know if I should do that on Windows too.

[noggin]

And something else: We don't do a pulldown ... never.

So what cadence would you expect for 24.000 at 60.00 or 23.976 at 59.94?

If I want to be anally retentive nothing does a pull-down apart from a telecine (which 'pulls down' the film frame)... But I'm interested to know what cadence you'd expect Kodi to deliver when playing non-native frame rates?

I assume 25p will be 2:2 at 50p? But what cadence would we expect instead of 3:2:3:2 or 3:2:2:3?

[FernetMenta]

This is a NVidia issue. Without tweaking it, you won't get 23.976 but 23.971.
I don't understand how a company can be that stupid or arrogant as NVidia. This bug is around since ever and they don't fix it.

[User 328513]

This is a NVidia issue. Without tweaking it, you won't get 23.976 but 23.971.

I don't think that is the problem. Correct me if I'm wrong in my assumptions here, but firstly, that mismatch would cause a stutter much less frequently (off by 0.005 FPS = off by 1 frame every 200 seconds), and secondly, I use "Sync playback to display" which adjusts the speed of the video slightly to make it match.

I don't understand how a company can be that stupid or arrogant as NVidia. This bug is around since ever and they don't fix it.

Money. Fixing this would most likely provide extremely little gain for them. Their resources (developers/time etc.) must be allocated where it gives the most return on investment (ROI), and there are probably areas which provide several orders of magnitude more ROI than fixing this bug. It's not stupidity, its not arrogance, it's just Nvidia looking out for their shareholders (which they're obligated to do). I could be wrong, but I don't think I'm far off.

[FernetMenta]

Could you try a recent v17 alpha?

[User 328513]

Could you try a recent v17 alpha?

Done, no change.

Again, as mentioned at first, I have this problem in other media players too on Linux (when manually setting the refresh rate to 24Hz).

[qp9013625]

This is a NVidia issue. Without tweaking it, you won't get 23.976 but 23.971.
I don't understand how a company can be that stupid or arrogant as NVidia. This bug is around since ever and they don't fix it.

Well, displays (monitors / TVs) can only refresh at integers anyway, right?

A display can not refresh at 23,976 Hz, right? It can only display at either 23,000 Hz or 24,000 Hz, right?

So why would you want to have your NVIDIA GPU output at 23,976 Hz at all?

The only thing that would make sense would be to speed up the video from 23,976 fps to 24,000 fps and make the GPU output at 24,000 Hz, wouldn't it?

I never really got that 23,976 vs. 24,000 fps / 29,970 vs. 30,000 fps / 59,940 vs 60,000 fps stuff.

I mean, why? TVs / monitors can only refresh at integer refresh rates anyway, don't they?