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TOPIC: Avoid 24p judder coming from big sensors

Avoid 24p judder coming from big sensors 2 weeks, 1 day ago #238027

  • timzett
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Since my main camera has a one inch sensor, I cannot always avoid pan-zoom combinations without 24p judder (while using a 180° shutter).

Now whenever I have such badly brought up clips, I am wondering whether there is any best-practice approach in Lightworks, in order to tweak this and hopefully manage to improve it a bit.

I tried the blur effect and speed changes but it doesn't improve anything noticeable.

Any hints, advices?
Lightworks Beta 2021.2 revision 128092, pro license, on Windows 10

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CAMs: Sony PXW-X70, NEX-5n, 2x Xiaomi Yi 1080p
Last Edit: 2 weeks, 1 day ago by timzett.

Re: Avoid 24p judder coming from big sensors 2 weeks, 1 day ago #238028

  • briandrys
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When shooting 24p, you need to avoid panning so fast as to get this effect. In the American Cinematographer Manual there are panning speed tables to avoid getting this. The size of the sensor doesn't matter, you'll still get it on 2/3" broadcast cameras when shooting at 24p and 16mm film cameras.

The difference is that film cameras have a mechanical shutter, which it is argued helps to "soften" it slightly compared to electronic shutters, but you will still get it if you move the camera too fast.

Try shooting with a slightly wider shutter angle than 180 degrees, to see if that improves things.

Re: Avoid 24p judder coming from big sensors 2 weeks ago #238052

  • hugly
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This guy seems to have invested a reasonable amount of time and money to get rid of the judder and explains it in a well understandable way:

It's better to travel well than to arrive...

Re: Avoid 24p judder coming from big sensors 2 weeks ago #238063

  • timzett
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Thanks guys for your answers.

I was actually aware of the problem and its workarounds, which is why I wrote
I cannot always avoid pan-zoom combinations without 24p judder
which especially applies to hand shots.

The shutter angle respectively shutter speed change is definitely a good means for introducing more motion blur and hence, limiting the visibility of the problem.

Anyway, I was rather at something to be improved in post, means for shots which already happened. Maybe there is a user effect or something, or a change of timeline/project settings to make this a little better?
While saying this, I also came across that one:
[Workaround] Canon Eos Judder in Lightworks
making me wonder if the problem is maybe even reinforced by the way Lightworks deals with the clips (until now I typically link them)?
I know the thread linked above is old, however I am wondering if transcoding still preserves a better handling of this than direct linking. I still had to try that.
Lightworks Beta 2021.2 revision 128092, pro license, on Windows 10

HARDWARE:
.Intel Core i7-4710HQ Quad-core 2,50 GHz, 16 GB DDR3 SDRAM
.GPU: NVIDIA GeForce GTX 860M with 2 GB RAM
.Sound: Onboard (Realtek)
.Disks: 250 GB SSD internal (OS/programs), 1 TB SSD internal for source footage

CAMs: Sony PXW-X70, NEX-5n, 2x Xiaomi Yi 1080p
Last Edit: 2 weeks ago by timzett.

Re: Avoid 24p judder coming from big sensors 2 weeks ago #238070

  • hugly
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The video I linked to above is truly worth watching, even if you have to watch it on Youtube, because the owner blocked linking the video from other sites.

timzett wrote:
I know the thread linked above is old, however I am wondering if transcoding still preserves a better handling of this than direct linking. I still had to try that.

Highly unlikely. I find the conversation there not very convincing anyway in our context. The guy seems to have performance problems, "judder" not caused by too fast panning, but by frame drops due to too demanding media on underpowered hardware, which is not so unlikely. However, because I never say never and don't know your system, give it a shot and let us know your findings.

By the way, this might also find your interest.

It's better to travel well than to arrive...
Last Edit: 2 weeks ago by hugly.

Re: Avoid 24p judder coming from big sensors 2 weeks ago #238080

  • schrauber
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timzett wrote:
... I was rather at something to be improved in post, means for shots which already happened.


I'm still experimenting there too.
In theory, one idea would be:
Higher fps with additional frames, synthetic generated from either:
- additional motion blur frames without changing the original frames.
-frame interpolation (third-party programmes).

With frame interpolation, however, artefacts can occur.

If the original material contains duplicate frames (or frames with too long a running time at a flexible frame rate) (camera too slow, etc.), these would also have to be interpolated / blurred.
Mainly automatically translated
--------------------------------------------
Software: Lightworks 2021.1 & 2021.2 (& old 14.x , 2020.x) || Windows 10 Home, 20H2, 64 Bit
Hardware: Intel i5-4440 (3,1 GHz); || RAM: 8 GB; || Intel HD Graphics 4600 (can use max. 2 GB of shared RAM)
Last Edit: 2 weeks ago by schrauber.

Re: Avoid 24p judder coming from big sensors 2 weeks ago #238084

  • hugly
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I believe the seven seconds rule together with a stable tripod creates certainly better results than frame interpolation. Check out Resolve, it has one of the best currently available interpolation algorithms, from my point of view, but honestly, the results depend highly on the content and are frequently not so convincing.
It's better to travel well than to arrive...

Re: Avoid 24p judder coming from big sensors 2 weeks ago #238100

  • timzett
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hugly wrote:
I believe the seven seconds rule together with a stable tripod creates certainly better results than frame interpolation.
In practice one doesn't always meet these conditions. These are good recommendations for scenic arrangements like on a film set for instance, but not for hand shots in the field.
A tripod may not be possible or at hand, and still you need to use a relativley long lens. Which means you may meet the worst conditions, with the opposite what is actually best-practice.
That is where post-fixes come in handy.

BTW I had watched the Youtube video instantly.
Lightworks Beta 2021.2 revision 128092, pro license, on Windows 10

HARDWARE:
.Intel Core i7-4710HQ Quad-core 2,50 GHz, 16 GB DDR3 SDRAM
.GPU: NVIDIA GeForce GTX 860M with 2 GB RAM
.Sound: Onboard (Realtek)
.Disks: 250 GB SSD internal (OS/programs), 1 TB SSD internal for source footage

CAMs: Sony PXW-X70, NEX-5n, 2x Xiaomi Yi 1080p
Last Edit: 2 weeks ago by timzett.

Re: Avoid 24p judder coming from big sensors 2 weeks ago #238102

  • hugly
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I would think removing judder caused by wrong panning speed in post is as difficult as removing motion blur in post. For reasonable results both need CGI.
It's better to travel well than to arrive...

Re: Avoid 24p judder coming from big sensors 1 week, 6 days ago #238140

  • timzett
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Very true.

I did a combination of a slightly increased blur effect and transcoding the affected clips in the timeline (to YUYV).
Subjectively, after the final export the result seems to be slightly better.
Lightworks Beta 2021.2 revision 128092, pro license, on Windows 10

HARDWARE:
.Intel Core i7-4710HQ Quad-core 2,50 GHz, 16 GB DDR3 SDRAM
.GPU: NVIDIA GeForce GTX 860M with 2 GB RAM
.Sound: Onboard (Realtek)
.Disks: 250 GB SSD internal (OS/programs), 1 TB SSD internal for source footage

CAMs: Sony PXW-X70, NEX-5n, 2x Xiaomi Yi 1080p

Re: Avoid 24p judder coming from big sensors 1 week, 6 days ago #238154

  • hugly
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That's one my favorites in terms of appealing camera movements, produced by Jacob + Katie Schwarz:

It's better to travel well than to arrive...

Re: Avoid 24p judder coming from big sensors 1 week, 5 days ago #238165

  • schrauber
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If the pan shows a landscape in which no significant moving objects or moving people are visible, then perhaps a DVE frame to frame sub-pan would be conceivable (manual frame interpolation with DVE)?

Idea would be to reduce the speed in the timeline to e.g. 25%, which adds to each frame 3 additional, initially identical frames. These 4 frames could be minimally panned with a DVE effect, so that the jump distance to the neighboring frame would be reduced to 25%.
But there would be many details to consider:
- The effect would have to be copied for each group of 4 frames (2000 effects for 2000 original frames). Alternative would be a remote control effect " rc_Zoom_regional_B.fx" with remote controllable position, controlled by "RC 3001, cyclic control" and basic settings + fine adjustment with "RC 1, Five channel remote". (in total 3 effects).
- Slight zoom required for the DVE pan.
- Exact adjustment of pan ranges; corrections may be required when changing main pan speed.
- Frame exact synchronization of the effects with the beginning and end of the respective 4-frame groups.
Mainly automatically translated
--------------------------------------------
Software: Lightworks 2021.1 & 2021.2 (& old 14.x , 2020.x) || Windows 10 Home, 20H2, 64 Bit
Hardware: Intel i5-4440 (3,1 GHz); || RAM: 8 GB; || Intel HD Graphics 4600 (can use max. 2 GB of shared RAM)
Last Edit: 1 week, 5 days ago by schrauber.
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