Judder effect (Monitor Gigabyte M320q + PotPlayer)

[rRondo]

Hello, I want to warn you that I am using Google Translate to write this text

After buying a new monitor, I faced a judder effect while watching movies. I don't have any problems while gaming (or in UFO test), but when I tried to watch movie —*landscape footage start “ghosting”, make's moving objects looks like they're shacking. I have tried PotPlayer and VLC with default setting, turned on DXVA in Potplayer setting — nothing helped.

I want to understand exactly what the problem is: the monitor (and its settings), the player (and its settings), Operating System (and its setting + graphic card setting) or just a codecs.

More information about specifications that might help:
Monitor: Gigabyte M320Q (31,5", 1440p, 165Hz)
Graphic Card: NVIDIA GeForce RTX 3060 Ti
Windows 11, PotPlayer and VLC

Ask me any questions, I will be glad to answer them. Thank you!

[rRondo]

Here is the video fragment where Judder effect shows up. Figures (and especially the hair) twitch very much when camera moving.

https://files.videohelp.com/u/307528/Barbie_judder_hair.mkv


I'v tried SVP technology build in PotPlayer, but it doesent help.


[Attachment 73804 - Click to enlarge]

[hello_hello]

I'm not all that familiar with the latest display technology, but until someone else comes along....

What refresh rate is the computer connected to the monitor? Is it 165Hz? Ideally the refresh rate should be an exact multiple of the frame rate.
165 / 24 = 6.875
If the refresh rate was 120Hz:
120 / 24 = 5
So each frame would display for 5 refreshes.

Have a look in the nvidia control panel, or whatever they call their control panel these days. I'd start by disabling everything in there that can mess with video specifically (not games), and see how it looks then. Except maybe any option for removing pulldown or telecine. It's probably a good idea to leave that enabled.

Have you tried adjusting the monitor's settings? There's possibly a preset for video, or even better, a preset that doesn't mess with the video. If you're using a gaming preset that could be part of the problem.

If it's nvidia settings, or monitor settings, or even the player's settings.... anything that can mess with the video.... disable everything you can disable and start from there.

[jagabo]

Yes, run your monitor at an integer multiple of 24 (or 23.976) fps (ie, 24, 48, 72, 96, 120...). You'll still get the inherent flicker of 24p but not the judder.

[hello_hello]

Here is the video fragment where Judder effect shows up. Figures (and especially the hair) twitch very much when camera moving.

https://files.videohelp.com/u/307528/Barbie_judder_hair.mkv


I'v tried SVP technology build in PotPlayer, but it doesent help.


[Attachment 73804 - Click to enlarge]

That video appears to have issues. The frames in the first second or two are repeated, and for that first second or so the video looks quite blurry. I thought the frames were displaying in the wrong order at first. The rest of the video plays normally using SMPlayer/MPV, with or without hardware decoding, although SMPlayer crashes at the end. VLC also plays it normally. I'm on Linux though so maybe there's an issue with nvidia's drivers. It wouldn't be the first time. When I was on XP I stopped updating the video drivers because doing so broke something more than once, but I guess Microsoft doesn't allow you to decide for yourself any more.

[jagabo]

Timestamps (ffprobe) show all the frames have a duration of ~42 ms (24000/1001 ms each). Except for frame 11 (the last frame before the shot change) which has a duration of ~84 ms.

[rRondo]

If someone have video for testing specifically judder effect —*please share with me.
I have seen the same "judder effect" earlier in another movie – Blade Runner 2049. In 2 or 3 scenes there were the same problems (but LosslessCut doesn't want me to show you these fragments).

[Attachment 73825 - Click to enlarge]

Here's info about "barbie.mkv" with judder scene:

General
Format                                   : Matroska
Format version                           : Version 4
File size                                : 21.0 GiB
Duration                                 : 1 h 54 min
Overall bit rate                         : 26.4 Mb/s
Frame rate                               : 23.976 FPS
Movie name                               : Barbie
Encoded date                             : 2023-09-12 16:44:55 UTC
Writing application                      : [url=https://www.videohelp.com/software/MKVToolNix]mkvmerge[/url] v78.0 ('Running') 64-bit
Writing library                          : libebml v1.4.4 + libmatroska v1.7.1
Cover                                    : Yes
Attachments                              : Cover.jpg

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L5@High
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 1 h 54 min
Bit rate                                 : 24.6 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0 (Type 2)
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.124
Stream size                              : 19.6 GiB (93%)
Default                                  : Yes
Forced                                   : No
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

Blade Runner 2049 with same problems

General
Unique ID                                : 52229678148055016106722612622177589138 (0x274B11F2EEB3A1DE4DA6C2F65F83D792)
Format                                   : Matroska
Format version                           : Version 4
File size                                : 29.0 GiB
Duration                                 : 2 h 43 min
Overall bit rate mode                    : Variable
Overall bit rate                         : 25.4 Mb/s
Frame rate                               : 23.976 FPS
Movie name                               : Blade Runner 2049
Released date                            : 2017
Encoded date                             : 2019-11-05 14:54:54 UTC
Writing application                      : mkvmerge v39.0.0 ('In The Waiting Line') 64-bit
Writing library                          : libebml v1.3.9 + libmatroska v1.5.2
Cover                                    : Yes
Attachments                              : cover.jpg


Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings                          : CABAC / 2 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 2 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 2 h 43 min
Bit rate mode                            : Variable
Bit rate                                 : 20.3 Mb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 23.976 (24000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.409
Stream size                              : 23.3 GiB (80%)
Title                                    : Blade Runner 2049
Language                                 : English
Default                                  : Yes
Forced                                   : No

[jagabo]

You get judder any time the display rate is not an integer multiple of the source rate. It's most obvious with sharp, high contrast, medium speed panning shots. And low frame rate (24p, 30p, etc.) always flickers under such conditions. This is nothing new. It's always been true.

[jagabo]

Downscaled, 8 bit, and simpler to decode. Same judder.

[rRondo]

You get judder any time the display rate is not an integer multiple of the source rate. It's most obvious with sharp, high contrast, medium speed panning shots. And low frame rate (24p, 30p, etc.) always flickers under such conditions. This is nothing new. It's always been true.

What can I do with this? Is there any tips what to do to avoid flickering? Maybe some setting in PotPlayer can make those shots smoother?
Thanks!

[jagabo]

If you have a fast CPU/GPU you could try using PotPlayer's ability to use AviSynth:


[Attachment 73856 - Click to enlarge]

I set the frame rate there to 55 fps since that's 1/3 of your refresh rate. That should give you smooth motion if your computer is fast enough. You'll need to install AviSynth+, the Interframe filter for AviSynth, and any other filters Interframe requires. That type of frame rate interpolation often doesn't work well (it may generate gross distortions). And it may not be fast enough for your 4K video.

[jagabo]

Here's what that filter delivers at 55 fps. Does it play any smoother for you? Notice all the distortions?

[rRondo]

Hi, jagabo. First of all, thanks you!
I've tried your 55 fps Barbie_55.mkv fragment. This file playing very smoothly, if not reduction in quality — it would be perfect

But AviSynth says that this script setting (on screenshot) have error: "Script error: There is no function named 'InterFrame'-. (potplayer_avisynth_script, line 2)"

also, is there any option to install AviSynth+ (plus) to PotPlayer?

[jagabo]

InterFrame is a third party AviSynth filter (ie, it doesn't come with AviSynth). You need to download and install Interframe and SVPFlow.

https://www.spirton.com/uploads/InterFrame/InterFrame2.html
https://www.spirton.com/uploads/InterFrame/InterFrame-2.8.2.zip

The zip file contains the SVPFlow dll's.

Potplayer will use Avisynth+ if that's the only version of Avisynth installed.