Blur moving object - any simple approach

[Makrand]

Hi there,

Is there any simple apporach to blur a moving object without adding addtional video track and using crop there? (here is example - Shotcut Tutorial: How To Track And Blur A Moving Face Or Object. - YouTube).

Usecase - a screencast recording where one is filling online details and scroll a lot arond…need to blur sensitive data that just keeps moving along with scroll action. Also, the sensitve data occupies the multiple parts of the online form (multiple text boxes of form) at random places in form.

[Elusien]

See the tutorial in my post below for a possible solution:

Obscure Part of a Video Using the "Spot Remover" filter

I have created a short (3 minute) video on how to obscure part of a video using the “Spot Remover” filter . There are other ways to do this, e.g. using the “Mask: Simple Shape” filter followed by the “Mosaic” and “Mask: Apply” filters, but I find this one to be the simplest and is probably the easiest to use.

[Makrand]

Thanks. Will look into it. This is somewhat similar to the built in YouTube studio editor blur effect. On there you can apply multiple blur spots in single clip at different locations.

What if I have to mask multiple spots/areas in single clip? Placed apart from each other? Possible in shortcut?

[MusicalBox]

@Makrand

What if I have to mask multiple spots/areas in single clip? Placed apart from each other? Possible in shortcut?

Using Elusien’s method, yes, it is possible.
Simply add a Spot Remover filter for each area of the screen you want to blur.

In the example below, I could even use 3 Spot Remover to hide the licence plates of 4 cars.
The one from the white car is reused for the grey car.

Screen capture of the Shotcut window:

[iwmmxxi]

From what I can see from this tutorial you have to go frame by frame to change where the blur effect resides. From my understanding, Shotcut would need to adopt a machine learning approach with object recognition to follow number plate / license plates. I’m excited by that idea but the size and editor’s OS may require multiple approaches, increase the overall exe’s size, etc.

[MusicalBox]

@iwmmxxi

you have to go frame by frame to change where the blur effect resides.

It is not necessary to put keyframes on each frame of the video. The video I posted above is about 15 seconds long at 24 frames per seconds. So a total of 360 frames. But I used only between 15 and 20 keyframes per licence plate.

Here’s how I proceed most of the time:

• I add a keyframe on the first frame and position the blur effect
• I go to the last frame, add another keyframe and position the blur effect.
• I go back to the first frame and play the video
• I’ll add keyframes when the blur effect starts to deviate from the target.