Magic Mask reference frames won't cache

Does anyone know why Magic Mask in Fusion sometimes fails to cache the reference frames? As shown in this video:

playback is smooth until it reaches frame 36, which is set as the reference frame.

As far as I know. Magic mask is designed not to cache reference frames, but does cache all the others. Back in 18.6.6 version of Resolve, in fusion you could right click on the interface of one of the settings of magic mask and open the folder where cache is. Originally I though it would be just magic mask exported for free, but I learned than that all was cached except reference frames. You have to ask developers why this is the way it is, I can only offer a personal guess.

If you made strokes and made a selection, than that part gets stored as part of the tool usage, not cached in temporary place on the disk. Its same as using the tool as a node. It gets stored in the composition. Like when you use color corrector tool or transform tool and you make a change. The bulk of it the cached frames are the the in-between frames, and when you delete or lose cache they get invalidated and you have to re-track, but you don't have to make the reference frame strokes again. In that way it acts as a fail safe against losing or deleting cache .

Technically you could make every frame a reference frame, and you would not lose it, it would ship along with the composition. I've done that actually myself. So to my understanding, that is why reference frames are not cached, its not that they won't, its the design choice.

As far as I know. Magic mask is designed not to cache reference frames, but does cache all the others. Back in 18.6.6 version of Resolve, in fusion you could right click on the interface of one of the settings of magic mask and open the folder where cache is. Originally I though it would be just magic mask exported for free, but I learned than that all was cached except reference frames. You have to ask developers why this is the way it is, I can only offer a personal guess.

If you made strokes and made a selection, than that part gets stored as part of the tool usage, not cached in temporary place on the disk. Its same as using the tool as a node. It gets stored in the composition. Like when you use color corrector tool or transform tool and you make a change. The bulk of it the cached frames are the the in-between frames, and when you delete or lose cache they get invalidated and you have to re-track, but you don't have to make the reference frame strokes again. In that way it acts as a fail safe against losing or deleting cache .

Technically you could make every frame a reference frame, and you would not lose it, it would ship along with the composition. I've done that actually myself. So to my understanding, that is why reference frames are not cached, its not that they won't, its the design choice.

Thank you very much for the detailed explanation. The only thing I don't like about this behavior is that sometimes I just want to see my preview in real time and the playback hangs just when it reaches reference frames of the Magic Mask. I know I can render a bitmap sequence but in some cases, I'm doing something so simple that I don't want to export an alpha sequence.

Thank you very much for the detailed explanation. The only thing I don't like about this behavior is that sometimes I just want to see my preview in real time and the playback hangs just when it reaches reference frames of the Magic Mask. I know I can render a bitmap sequence but in some cases, I'm doing something so simple that I don't want to export an alpha sequence.

If it hinders playback performance, perhaps its not related to caching of that frame because of magic mask per se, but because of some other setting related to storing data for playback. I am not behind fusion at the moment so I can't check, but try to "force cache" on the magic mask node. If you know the setting I mean. Right click on the node and under mode or settings or something like that, there is force cache option. It should prioritize overall playback cache to that node. See if that changes anything.

I am no longer certain after you mentioned it, does it stutter for me as well or not. But I'll check next time I'm using magic mask.

I've checked and indeed when it reaches reference frame it has to recalculate at least particularly the selection, leading to stutter in playback. The only thing, other than caching or exporting the node, is to do preview render pass which may speed up preview. In fusion.

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I've checked and indeed when it reaches reference frame it has to recalculate at least particularly the selection, leading to stutter in playback.

Yes, I hope this will be fixed, perhaps by adding a "done" button in the magic mask to not force the recalculation of reference frames.

The only thing, other than caching or exporting the node, is to do preview render pass which may speed up preview. In fusion.

That preview render option looks pretty neat! I never used it before. Can you give a quick explanation of how this works and where it stores the frames on the pc?

That preview render option looks pretty neat! I never used it before. Can you give a quick explanation of how this works and where it stores the frames on the pc?

To be honest, I found it myself the other day. So I'm still experimenting. Seems to work better in fusion studio than in resolve page of Davinci, probably because that is its native origin.

The manual says this:

Rendering Previews

You can render Flipbook previews into a viewer. These Flipbook previews exist entirely within RAM. They are created by right-clicking over a node in the Node Editor and choosing Create > Play/Preview on > Left viewer/Right viewer from the drop-down menu. The Render Settings dialog appears where you can configure the preview and initiate the rendering.

You can also Option/ALT-drag a node directly from the Node Editor into a viewer. The Render Settings dialog will be displayed, and the preview will appear on the viewer you target.

TIP: Option-Shift-dragging a node into a viewer will skip the Render dialog and previously used settings

Playing Flipbook Previews

While the Flipbook Preview is loaded into a viewer, or open in full-screen mode, you can play or scrub through it using the mouse and the keyboard.

To play back a Flipbook using the mouse, do the following:

— Double-click in the viewer to start playback.

To scrub through a Flipbook using the mouse, do the following:

— Hold down the right mouse button down and drag left or right to scrub through frames.

To play back a Flipbook using the keyboard, do one of the following:

— Press the Spacebar to start or stop playback.

— Hold Shift and press the Spacebar to play in reverse.

To scrub through a Flipbook frame-by-frame using the keyboard, do one of the following:

— Press the Left or Right Arrow keys to move to the previous or next frame.

— Hold Shift and press the Left or Right Arrow keys to jump back or forward 10 frames.

— Press Command-Left Arrow to jump to the first frame.

— Press Command-Right Arrow to jump to the last frame.

TIP: The mouse and keyboard shortcuts work in full-screen mode as well.

Removing Flipbook Previews

Once you create a Flipbook Preview, you need to know how to clear it from RAM.
To eliminate a Flipbook you’ve created:

— Right-click within a viewer containing a Flipbook Preview, and choose Remove Preview.

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For more information on rendering RAM previews, see Chapter 69, “Using Viewers.” in the DaVinci Resolve Reference Manual or Chapter 7 in the Fusion Reference Manual