From normal image to circle and from circle to normal image

Hi,

Let’s admit we have normal full screen image. I would like to make transition to look this image like circle (sure with black borders) and then after some time to return smoothly to normal rectangle view (standard view).

The first idea was to use “360 equirectangular to rectilinear” filter and true it gives nice circle image (something like very strong fish eye). Unfortunately I’m not able to get neutral position with this filter, thus transition (with keyframes) is not possible.

Another attempt “Fish eye” filter. But here the “power” of this filter is too low. It’s not possible to get fully circular image (or perhaps I don’t know how).

Any other ideas?

I was able to create this, but it involves quite a lot of steps…

My project was set to 1920x 1080, at 30 fps.

Step 1

First, to turn the image into a sphere, I used the Fisheye filter with these settings:

Setting Value
Fisheye : Add
Focal Ratio: 1000
Quality: Nearest neighbour
Lens: Orthographic
I left the other settings to default.

Problem: One Fisheye filter is not enough to create a sphere.
Solution: I added identical copies of the filter until the image was turned into an almost perfect circle. I didn’t want to add too much copies, because each time you add one, you loose a little image quality and Shotcut get slower. So I ended up using 11 copies.

shotcut_zk95HJePZA.

Step 2

Now we need to gradually turn the rectangle image into a sphere.

Problem: You can’t add keyframes to the Fisheye filter.
Solution: Make each copy of the filter start being active at 2 frames intervals.

For that, I used Set Filter Start and Set Filter End in the Keyframes timeline.

shotcut_pIapNHslxA

Note: For the sake of reusability, don’t do the steps below in your main project. Create a separate Shotcut project, add ONE track, import an image to that track and add the 11 Fisheye filters.

  Steps:

  • Move the Playhead to the FIRST frame of the clip
  • Move the Playhead ahead 2 frames.
  • Select the 1st Fisheye filter in the filters list.
  • Press the Set Filter Start button in the keyframes timeline.
    So for the first 2 frames of the clip, the image is still rectangular, and when the Playhead gets to the third frame, the first Fisheye filter kicks in.
  • Move the Playhead ahead 2 frames.
  • Select the 2nd Fisheye filter in the filters list.
  • Press the Set Filter Start button.
  • Move the Playhead ahead 2 frames.
  • Select the 3th Fisheye filter in the filters list.
  • Press the Set Filter Start button.
  • Repeat the last 3 steps for each of the remaining filters in the list.
  • Move the playhead ahead for 1 second.
  • Select the LAST filter in the list.
  • Press the Set Filter End button.
  • Move the Playhead ahead 2 frames.
  • Select the filter ABOVE.
  • Press the Set Filter End button.
  • Repeat the last 3 steps for each of the remaining filters in the list.

Step 3

Now we want to save this project as a template. This will allow you to recreate this effect without having to go trough all these steps again.
Go to File > Save As…, choose an easy to find location, and give the project a name like:
spherize-image_TEMPLATE.mlt for example.

Step 4

Export with transparency.

  • Go to the Export tab.
  • Choose Quicktime Animation in the Presets list.
    shotcut_dqJVIkaHRo
  • Press the Export button.

Now you can go back to your main project, import the MOV video you just exported, and use filters to resize it, position it, and, animate it if you want to (with keyframes).
Everything except the image will be transparent.

I hope these instruction are clear enough (I have doubts). I realize this is complicated, but so far it is the only way I found to create this effect. Feel free to ask questions if you need to.

EDIT: If you find that the animation is a bit choppy when the rectangle turns into a circle (and back to the rectangle), you can improve it by using 1-frame intervals instead of 2. The animation will not last as long though. You could compensate by using more than 11 filters (if your computer can handle it)

4 Likes

Thanks a lot for these hints. You put a lot of effort. Thank you.

However it’s a pity it’s not possible to do this only with one filter. Perhaps extending fisheye range would be a good idea… How do you think?

You’re welcome @NoName

I agree. In this particular case it would have helped a lot.
Keyframes would be nice too on the Fisheye filter.

But until then, the method explained above is the only workaround I can see.

2 Likes

I changed the category of this thread from “How to” to “Suggestion”.

Concluding we would propose two things concerning Fisheye filter:

  1. Extend fisheye “power” (=much higher and much lower values possible for focal lenght parameter).
  2. Adding keyframes.

:slight_smile:

Sorry, I’m not a programmer, but by scientific keyboard poking, I managed to add the missing keyframes to the fisheye filter myself. And I will be very happy if someone helps me finish this filter.
I added an archive with my experience, if someone manages to improve it and bring it to the end, I will be very happy.
fisheye.zip (7.0 KB)

2 Likes

The Lens Correction filter was already restored for the next version (including alpha), and it supports keyframes. I already have enough to do that I do not want to adopt this as I can already see it will need more work (Manual Scale and Manual Aspect in addition to Focal Ratio plus simple keyframes).

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