Eevee/Cycles motion blur not taking into account Time Remamaping in VSE #91927

New Issue

Dmitry · 2021-10-03T21:29:58+02:00

Dmitry commented

2021-10-03 21:29:58 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.11

Blender Version
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-10-02 22:34, hash: 34cf33eb12
Worked: (newest version of Blender that worked as expected)

Short description of error
Remapped scenes should have adequate motion blur if that is possible.

Right now the added scenes are treated as a set of animation keys, not as a rendered sequence of frames.
And if so, then the motion blur should be processed after the fact of the speed remapping in VSE, but it remains the same as in the original scenes.

Exact steps for others to reproduce the error

Added two scenes into VSE
Grouped it
Remapped the speed
Rendered

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.11 **Blender Version** Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-10-02 22:34, hash: `34cf33eb12` Worked: (newest version of Blender that worked as expected) **Short description of error** Remapped scenes should have adequate motion blur if that is possible. Right now the added scenes are treated as a set of animation keys, not as a rendered sequence of frames. And if so, then the motion blur should be processed after the fact of the speed remapping in VSE, but it remains the same as in the original scenes. **Exact steps for others to reproduce the error** 1) Added two scenes into VSE 2) Grouped it 3) Remapped the speed 4) Rendered

Dmitry commented

2021-10-03 21:29:58 +02:00

Added subscriber: @Rockbard

Richard Antalik commented

2021-10-03 23:09:54 +02:00

Added subscriber: @iss

Richard Antalik commented

2021-10-03 23:09:54 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Richard Antalik commented

2021-10-03 23:09:54 +02:00

Please upload simple example file. I am not sure if you use speed effect or scene time remapping method. Either way I wasn't able to reproduce the issue.

Dmitry commented

2021-10-04 10:43:39 +02:00

I'm sorry, I thought the project file is attaching automatically.
Please, see the attachment. Speed remapping Motion blur.blend

P.s. I'm using the Speed Effect

I'm sorry, I thought the project file is attaching automatically. Please, see the attachment. [Speed remapping Motion blur.blend](https://archive.blender.org/developer/F10760285/Speed_remapping_Motion_blur.blend) P.s. I'm using the Speed Effect

Richard Antalik commented

2021-10-11 14:11:32 +02:00

I am not really sure I follow this report - in both scenes animation is so slow, that motion blur has almost no visible effect.

Then from description:

Right now the added scenes are treated as a set of animation keys, not as a rendered sequence of frames.

What do you mean by this? A scene has mostly it's own properties, though some are overridable in VSE. Rendering scene strip in VSE should be the same as rendering scene itself into image sequence and importing this sequence into VSE.

And if so, then the motion blur should be processed after the fact of the speed remapping in VSE, but it remains the same as in the original scenes.

VSE has no implementation for motion blur currently, even though it is hosted in scene that has this property. So whether it is enabled or not should have no effect on render result.

I am not really sure I follow this report - in both scenes animation is so slow, that motion blur has almost no visible effect. Then from description: >Right now the added scenes are treated as a set of animation keys, not as a rendered sequence of frames. What do you mean by this? A scene has mostly it's own properties, though some are overridable in VSE. Rendering scene strip in VSE should be the same as rendering scene itself into image sequence and importing this sequence into VSE. > And if so, then the motion blur should be processed after the fact of the speed remapping in VSE, but it remains the same as in the original scenes. VSE has no implementation for motion blur currently, even though it is hosted in scene that has this property. So whether it is enabled or not should have no effect on render result.

Dmitry commented

2021-10-11 21:03:00 +02:00

In #91927#1233686, @iss wrote:
Rendering scene strip in VSE should be the same as rendering scene itself into image sequence and importing this sequence into VSE.

Well, yes and no. If you will use an image sequence and slow it down beyond a certain level in VSE you will get a pretty jerky motion.
On the other hand, slowing down the native scenes in VSE will always leave you with a buttery smooth motion.

So VSE can operate on scene timing directly on its timeline, but it retaining the native motion blur of the used scene. (One more example: Motion blur test 2.blend)

Therefore, we can assume that with changing the scene timing the motion blur will be changed as well. But currently, it is not.

P.s. Richard I know I'm expressing my thoughts pretty rough due to my low level of English,
but I think this topic is quite interesting to discuss, if we could change the current way VSE handles the motion blur in scenes it could become much more useful.

> In #91927#1233686, @iss wrote: > Rendering scene strip in VSE should be the same as rendering scene itself into image sequence and importing this sequence into VSE. Well, yes and no. If you will use an image sequence and slow it down beyond a certain level in VSE you will get a pretty jerky motion. On the other hand, slowing down the native scenes in VSE will always leave you with a buttery smooth motion. So VSE can operate on scene timing directly on its timeline, but it retaining the native motion blur of the used scene. (One more example: [Motion blur test 2.blend](https://archive.blender.org/developer/F10978004/Motion_blur_test_2.blend)) Therefore, we can assume that with changing the scene timing the motion blur will be changed as well. But currently, it is not. P.s. Richard I know I'm expressing my thoughts pretty rough due to my low level of English, but I think this topic is quite interesting to discuss, if we could change the current way VSE handles the motion blur in scenes it could become much more useful.

Richard Antalik commented

2021-10-12 16:04:38 +02:00

Changed status from 'Needs User Info' to: 'Confirmed'

Richard Antalik commented

2021-10-12 16:04:38 +02:00

Ah sorry that was incorrect assumption on my part, scene strips really do support subframes.

So you are correct in that this doesn't work as expected. But I don't think this can be easily resolved.

Motion blur is property of renderer and it will always use settings from original scene. VSE could (technically) modify this, but it shouldn't do it. Unless there is better way to resolve this issue, such change won't be accepted.

I think that way to solve this would be to have ability to override or amend scene time remapping, since this is "native" to scene and all features that depend on time should support this. In fact this could be used to work around speed strip not working as intended.
See this example:
#91927-frame-remap.blend

Then however challenge would be to properly propagate this further, since speed effect can't just render strip directly as it does now, but it would have to create local context with speed factor and if there is another speed effect in chain, it will have to add it's own speed factor and so on.

Will set as known issue for now, since this isn't very trivial to resolve and at least will need design evaluation.

Ah sorry that was incorrect assumption on my part, scene strips really do support subframes. So you are correct in that this doesn't work as expected. But I don't think this can be easily resolved. Motion blur is property of renderer and it will always use settings from original scene. VSE could (technically) modify this, but it shouldn't do it. Unless there is better way to resolve this issue, such change won't be accepted. I think that way to solve this would be to have ability to override or amend scene time remapping, since this is "native" to scene and all features that depend on time should support this. In fact this could be used to work around speed strip not working as intended. See this example: [#91927-frame-remap.blend](https://archive.blender.org/developer/F11008767/T91927-frame-remap.blend) Then however challenge would be to properly propagate this further, since speed effect can't just render strip directly as it does now, but it would have to create local context with speed factor and if there is another speed effect in chain, it will have to add it's own speed factor and so on. Will set as known issue for now, since this isn't very trivial to resolve and at least will need design evaluation.

Dmitry commented

2021-10-12 19:41:56 +02:00

Ah, yes. My first thought was to modify imported scene native time remapping within the VSE using the speed effect, to bound these two somehow.
So the scene will continue to use its own motion blur settings, but now it will evaluate it with its new retiming settings.

Thank you for your time, Richard.
I hope this issue will be resolved in near future.

Ah, yes. My first thought was to modify imported scene native time remapping within the VSE using the speed effect, to bound these two somehow. So the scene will continue to use its own motion blur settings, but now it will evaluate it with its new retiming settings. Thank you for your time, Richard. I hope this issue will be resolved in near future.

Philipp Oeser removed the

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Eevee/Cycles motion blur not taking into account Time Remamaping in VSE #91927