1
$\begingroup$

I am using the video editing function of Blender to make a image pan & zoom clip (aka Ken Burns). The image is a chart I made in Photoshop and I want to zoom into an exact point on the chart and a exact zoom level.

In the effects strip controls, there are places to adjust the scale as well as the position, but I can't figure out how the values in these boxes translate to real-world values (in my case I want to go to exactly 300%, centered on the 508x291 pixel spot on the image).

$\endgroup$
4
$\begingroup$

This could be a solution with VSE, but you'll get a blurried image (if you scale 300%)

Some consideration first:

The effect strip will scale always from the center of the image.

If you want to scale from the point A (508x291px from the top-left corner), you have to move the point A to the center first, then scale.

Pan and zoom in VSE

  1. Add the first effect stript to translate the image by the offset you need.
  2. Add the second effet strip to scale (3 = 300%)

Some math:

If your image dimensions are 1920x1080px:

first effect strip (position)

center: xc=960, yc=540

pointA: xa=508, ya=291

translation: xc-xa, yc-ya = 960-508, 540-291 = 452, 249

enter image description here

second effect strip (scale)

scale 3 = 300%

As you can see, the quality of the image is very low. Since you are scaling 3 times the size, the resolution is 3 times lower.

enter image description here

Note

When you deal with scale in VSE, you have to pay attention to the original size and the render size.

When you add an image (or a movie clip) in the video sequencer editor, the image will be scaled to the render size.

If you want the image to maintain the original size, you have to check the "Image offset" option (transform in pixel).

enter image description here

Doing so, you can pan the image and center the point of interest but you cannot scale it down, because the image will be cropped.

If you want to zoom an image, I suggest you to use the node compositor or a camera moving in front of an image plane in 3d View.

Pan and zoom in 3D View

Using the 3d View, the image texture can be bigger than the render size.

  1. Activate the "import images as planes" add-on, if it is not yet activated

enter image description here

  1. Import the image to stage enter image description here

enter image description here

Some considerations about the options:

  • Check "Shadeless"
  • If you're importing image with alpha channel (png), check "Use Alpha" and "Z Transparency"
  • If you want the image to have precise dimensions, the best choice is "Plane dimensions: Dots/BU)": it allows you to determine the dimensions starting from the pixel size (eg: 1920 x 1080px at 100 Dots/BU -> plane dimensions: 1.920 x 1.080 BU)

Pan and zoom in Node Compositor

Here a possible node compositing:

enter image description here

| improve this answer | |
$\endgroup$
  • $\begingroup$ Thanks for these hints. I added another "Scene" that only does the animated image transform with the Node Editor as suggested and was able to use this in the original Scene in the Video Sequence Editor (VSE) instead of an effect strip. $\endgroup$ – handle Jan 29 '17 at 19:37
0
$\begingroup$

In the sidebar for the Transform Effects strip you'll see 2 fields for Scale X and Y. The default value is 1.0 which equates to 100% scale of the clip to be transformed. Animating the XY scale values up to 3.0 should give you the 300% scale effect.

For the position values, the XY values are also percentage, but this time 50 = 50% and 100=100%. To animate the position to the exact spot on the screen, I think you'll have to use the trial and error method and eyeball it to get something that works how you want.

enter image description here

| improve this answer | |
$\endgroup$
  • $\begingroup$ The transform effect strip is what you will be using. Just understand that it has several different operating modes depending on whether you choose Translation = Percent or Pixels, and do you check the Image Offset box? $\endgroup$ – Mutant Bob Jul 13 '15 at 21:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.