WIP: Compositor: add aspect ratio display in node viewer #106338

Node viewer can now show the image with desired aspect ratio (does not affect render).

Attached gif shows how the UI looks like. Existing functionalities like backdrop offset and scaling through backdrop gizmo still behave the same as before.

WIP: defaults are not working / Might need tweeks to UI depending on feedback / Code style

Node viewer can now show the image with desired aspect ratio (does not affect render). Attached gif shows how the UI looks like. Existing functionalities like backdrop offset and scaling through backdrop gizmo still behave the same as before. WIP: defaults are not working / Might need tweeks to UI depending on feedback / Code style

Screen Recording 2023-03-30 at 21.08.24.gif

2.5 MiB

@SteffenD behavior of aspect ratio is the same as in image and movie clip editors. Is that also how you would expect it to behave (see attached gif)?

@Jeroen-Bakker I'm having a hard time setting default values for the new values. I tried the following:

RNA_def_property_float_default(prop, 1.0f); in rna_space.c
setting snode->xasp = 1.0f; in node_create() in space_node.c
defining a new struct in DNA_space_defaults.h

But Blender still sets values to 0.0f on start. Could you help me by pointing out where defaults get set?

@SteffenD behavior of aspect ratio is the same as in image and movie clip editors. Is that also how you would expect it to behave (see attached gif)? @Jeroen-Bakker I'm having a hard time setting default values for the new values. I tried the following: 1. ` RNA_def_property_float_default(prop, 1.0f);` in `rna_space.c` 2. setting `snode->xasp = 1.0f;` in `node_create()` in `space_node.c` 3. defining a new struct in `DNA_space_defaults.h` But Blender still sets values to `0.0f` on start. Could you help me by pointing out where defaults get set?

@SteffenD behavior of aspect ratio is the same as in image and movie clip editors. Is that also how you would expect it to behave (see attached gif)?

Awesome! The behaviour in the GIF is perfect :)

> @SteffenD behavior of aspect ratio is the same as in image and movie clip editors. Is that also how you would expect it to behave (see attached gif)? Awesome! The behaviour in the GIF is perfect :)

@SteffenD ok thanks!

After some investigation I found out that creating a new compositor space will have the correct defaults (from step 2 above). RNA_def_property_float_default is called when user clicks "Reset to Default Value". So the only way of starting blender with the desired values is to edit the startup blend file startup.blend. Is this correct?

@SteffenD ok thanks! After some investigation I found out that creating a new compositor space will have the correct defaults (from step 2 above). `RNA_def_property_float_default` is called when user clicks "Reset to Default Value". So the only way of starting blender with the desired values is to edit the startup blend file `startup.blend`. Is this correct?

Another approach would be to pass the aspect ratio via the meta data and use it. Might be better than adding an option. But requires more work as nodes can alter the aspect ratio.

I can imagine that the in the proposed solution the user has to alter the aspect ratio based on what they are looking at and that is adding more work towards the user. Although we might want the user to tweak final values, I do think this should be made as automatically as much as possible.

Another approach would be to pass the aspect ratio via the meta data and use it. Might be better than adding an option. But requires more work as nodes can alter the aspect ratio. I can imagine that the in the proposed solution the user has to alter the aspect ratio based on what they are looking at and that is adding more work towards the user. Although we might want the user to tweak final values, I do think this should be made as automatically as much as possible.

@Jeroen-Bakker but this is how the movie clip editor and the image editor change display ratio. The user has to alter the aspect ratio manually there also. So this patch addresses the consistency problem.

I agree this should be done as automatically as possible, but is it possible to do that as a next step after this patch?

@Jeroen-Bakker but this is how the movie clip editor and the image editor change display ratio. The user has to alter the aspect ratio manually there also. So this patch addresses the consistency problem. I agree this should be done as automatically as possible, but is it possible to do that as a next step after this patch?

In the image editor the aspect ratio is stored inside the image, so when switching the image the correct aspect ratio is used. Same for movie clip editor.

This patch stored the aspect ratio as node attribute, which in case you're switching inputs the aspect ratio will that of the node. This is different (from user point of view) compared to the other editors.

The display aspect inside the image/movie clip editor is read from the next locations.

Even render results have aspect ratios. There might be issues when mixing or other ways where aspect ratios cannot be decided. In these cases I can expect that the node will have an aspect ratio.
These limitations might require a different UI as there are quite a few options already:

Use aspect ratio from node (this patch)
Use aspect ratio from input.
Use aspect ratio from render layer.
Use aspect ratio from scene.

So to find out the correct location we should collect user feedback.

@eyecandy do you have any ideas about viewer node display aspect ratios? and how you would use them

In the image editor the aspect ratio is stored inside the image, so when switching the image the correct aspect ratio is used. Same for movie clip editor. This patch stored the aspect ratio as node attribute, which in case you're switching inputs the aspect ratio will that of the node. This is different (from user point of view) compared to the other editors. The display aspect inside the image/movie clip editor is read from the next locations. - https://docs.blender.org/api/current/bpy.types.Image.html#bpy.types.Image.display_aspect - https://docs.blender.org/api/current/bpy.types.MovieClip.html#bpy.types.MovieClip.display_aspect Even render results have aspect ratios. There might be issues when mixing or other ways where aspect ratios cannot be decided. In these cases I can expect that the node will have an aspect ratio. These limitations might require a different UI as there are quite a few options already: - Use aspect ratio from node (this patch) - Use aspect ratio from input. - Use aspect ratio from render layer. - Use aspect ratio from scene. So to find out the correct location we should collect user feedback. @eyecandy do you have any ideas about viewer node display aspect ratios? and how you would use them

@eyecandy I was wondering if you had a chance to look at this? I have time to work on this next week...

I checked with @eyecandy and we are struggling with finding the usage/benefit of this patch. I still believe that this should be collected from the input of the node tree where the viewer is connected to and not being a setting on the viewer node.

Can someone clarify what actual issue this solves and why adding the aspect rations in the viewer node is needed.

I checked with @eyecandy and we are struggling with finding the usage/benefit of this patch. I still believe that this should be collected from the input of the node tree where the viewer is connected to and not being a setting on the viewer node. Can someone clarify what actual issue this solves and why adding the aspect rations in the viewer node is needed.

@Jeroen-Bakker / @eyecandy I see, thanks for looking into this.

For me it's just a problem of consistent viewing across the different editors. If you work with anamorphic input then you will be able to display the correct aspect in movie clip editor and image editor but not in node editor (see attachment). I am not aware of a solution to this, that's why I submitted the patch.

As for implementation I don't have a strong opinion, I would go with Jeroen's suggestion if we agree backdrop must consider aspect ratio.

@Jeroen-Bakker / @eyecandy I see, thanks for looking into this. For me it's just a problem of consistent viewing across the different editors. If you work with anamorphic input then you will be able to display the correct aspect in movie clip editor and image editor but not in node editor (see attachment). I am not aware of a solution to this, that's why I submitted the patch. As for implementation I don't have a strong opinion, I would go with Jeroen's suggestion if we agree backdrop must consider aspect ratio.

image.png

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We discussed this in the VFX meeting, and I thought we might as well add the option here for those working with anamorphic video files. But I changed my mind after looking at this more closely.

The issue is that compositing in general doesn't work correctly on anamorphic video, filters and transforms will give wrong results. The workflow in a few other compositing apps seems to be to desqueeze the image with a node before processing it, rather than having viewer options for aspect ratio. I think that's what we should recommend too, rather than going in the direction of a workflow where we will hit limitations at some point anyway.

We discussed this in the VFX meeting, and I thought we might as well add the option here for those working with anamorphic video files. But I changed my mind after looking at this more closely. The issue is that compositing in general doesn't work correctly on anamorphic video, filters and transforms will give wrong results. The workflow in a few other compositing apps seems to be to desqueeze the image with a node before processing it, rather than having viewer options for aspect ratio. I think that's what we should recommend too, rather than going in the direction of a workflow where we will hit limitations at some point anyway.

You indeed need to "unsquish" the input, otherwise things like lens distortion will not work (as it is in the non-squished space, and caibraiton can not be mapped form one to another).

What I am not sure is whether you "squish" the image back before writing it to disk. You probably don't for the final output, if you're creating a clean plate maybe there are some benefits for squishing things back.

But now when I think of it, you probably will not use the viewer node to look into the squished result, as it will be at the end. And if the output image is to be squished, and you still want to see it, you can use the aspect ratio in the image editor.

There are couple of things I am wondering though.

I think @sebastian_k worked on anamorphic videos before and can share his experience and help prioritizing changes.
Habib, is it something coming from a discussion on devtalk where we can read-up a bit and understand if the "unsquish" workflow is not desirable there?

You indeed need to "unsquish" the input, otherwise things like lens distortion will not work (as it is in the non-squished space, and caibraiton can not be mapped form one to another). What I am not sure is whether you "squish" the image back before writing it to disk. You probably don't for the final output, if you're creating a clean plate maybe there are some benefits for squishing things back. But now when I think of it, you probably will not use the viewer node to look into the squished result, as it will be at the end. And if the output image is to be squished, and you still want to see it, you can use the aspect ratio in the image editor. There are couple of things I am wondering though. - I think @sebastian_k worked on anamorphic videos before and can share his experience and help prioritizing changes. - Habib, is it something coming from a discussion on devtalk where we can read-up a bit and understand if the "unsquish" workflow is not desirable there?

Thanks for looking into this patch.

I approached this as a bug after fixing #105590, not as a direct user request, so I don't have a strong opinion on how anamorphic input should be handled.

The idea of the patch #106121 is indeed to "squish" the mask before applying it to the image in order to have correct results. So I see 2 options on how to proceed here:

Do nothing: leave it to the user to un-squish the input image and squish it back before saving
Let Blender handle aspect ratio implicitly, e.g.
- add node "set aspect ratio" that un-squishes the input or read aspect ratio from render settings
- change all output nodes to scale the output before displaying or saving

Thanks for looking into this patch. I approached this as a bug after fixing #105590, not as a direct user request, so I don't have a strong opinion on how anamorphic input should be handled. The idea of the patch #106121 is indeed to "squish" the mask before applying it to the image in order to have correct results. So I see 2 options on how to proceed here: 1) Do nothing: leave it to the user to un-squish the input image and squish it back before saving 2) Let Blender handle aspect ratio implicitly, e.g. - add node "set aspect ratio" that un-squishes the input or read aspect ratio from render settings - change all output nodes to scale the output before displaying or saving

I think that if you're doing any non trivial compositing, your camera input may be anamorphic but there's no good reason to output it anamorphic again. It's a quirk that cameras work this way, and it's good to get raw data from the camera without scaling so that you have as much control as possible in compositing. But for the final output, I don't see the point.

A utility node to scale anamorphic footage could be nice. Or even an option for image reading also available in the sequencer.

I think that if you're doing any non trivial compositing, your camera input may be anamorphic but there's no good reason to output it anamorphic again. It's a quirk that cameras work this way, and it's good to get raw data from the camera without scaling so that you have as much control as possible in compositing. But for the final output, I don't see the point. A utility node to scale anamorphic footage could be nice. Or even an option for image reading also available in the sequencer.

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WIP: Compositor: add aspect ratio display in node viewer #106338