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Obstacles seem to compound themselves to stop me from accomplishing it.

  1. How to pan the scene to find the target spot at a very high zoom? Before I can set Position: X, Y values in Transform effect strip, I must find the target spot. However, once I set the desired Scale to a high value (150×), there is no obvious way to navigate (pan) the zoomed-in scene (either a Movie strip or an Image strip) in order to find the target spot. Output is cropped to the Render Area and zooming out by mouse fails to reveal neighbourhood outside the Render Area. Even if there is some way to turn off default cropping (please, let me know), GUI in the preview area is not responsive to panning by mouse. Trying to reverse the workflow by centering the scene to the target spot first (Position: X, Y), and setting Scale next, is a futile exercise because scaling doesn’t preserve Position values. (Changing the Scale value moves the target spot out of view despite unchanged Position values.) It’s even harder when the resolution is low because all I can see is a blob of interpolated pixels, so I can’t tell where I am and in which direction I should aim thence. (See screenshot.)enter image description here

  2. Why does exponential interpolation mode fail during superzoom? By its nature, superzoom is an exponential process. But when the Interpolation Mode (in Graph Editor) for Key Frames based on Scale (in Transform effect strip) is set to anything other than basic modes (for example to Sinusoidal or Exponential rather than default Bezier), the result is so erratic that I must presume it’s a bug in Blender (version 2.74).

  3. How to align zooming-panning Transform interpolation curves of two different scene strips (each starting and ending at different time points) to accomplish coherent blending transition from one to another? (From a low-resolution view to a high-resolution view in this particular case.)

  4. I can’t remember other obstacles at the moment. I may add them later.

Should I split this question into four separate posts?

Edit: 8 November 2016

  1. Stacking Transform filter on top of another Transform filter to solve some of the above issues results in transforming a strip cropped to the Render Area by the first filter instead of the full source material.

  2. No one knows anything. It’s as if no one has ever produced a zoom effect in a video. It’s as if there are no Blender experts among the living and Blender had created itself alone. No one knows any other software that allows to get it done. No one even knows what’s wrong with my question. No one knows who else knows. Zooming in on a spot in a video: rocket science.

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  • $\begingroup$ The VSE rescales any image to fill the dimensions of the scene. So any zoom you do there is only re-sampling this pre-scaled image. If you turn off that function per strip thn the VSE crops the image by the scene dimensions, so you can't scale the cropped sides back in. That might be why no-one has replied. Last time I needed to do this I just stacked the images as planes in 3D view and flew the camera over them. Alternatively you could use a UV pass from 3D view to remap images in the compositor. $\endgroup$ – 3pointedit May 2 '17 at 7:01
  • $\begingroup$ @3pointedit: Rendering the camera flight over stacked 3D planes (each with a progressively higher degree of texture detail) to accomplish a superzoom effect – yes, I have tried it too. It works... but it takes 100× more CPU time. (Any ideas how to disable unnecessary rendering options? I have hoped to use the Blender Game engine because it’s supposed to work in real time. Sadly, when I switch to it, the options to produce a video file disappear...) $\endgroup$ – 7vujy0f0hy May 2 '17 at 9:53
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    $\begingroup$ Oh you can absolutely export the viewport version using OpenGL render. Thats what the little clapper board icon at the bottom of the 3D view is for. Check out these great video tutorials for hacking the viewport youtube.com/… $\endgroup$ – 3pointedit May 2 '17 at 11:55
  • $\begingroup$ @3pointedit: Fantastic! You’ve just opened up a whole new world of possibilities to me. If you want to post it as an answer (stacked 3D planes + camera flight + viewport rendering), I will mark it as a solution. It’s a workaround really, since it doesn’t solve any of the described issues, but it’s a very powerful workaround – and it accomplishes the end goal of an animated superzoom video scene in Blender. It’s even more useful than a proper solution would be. Meanwhile, if anyone else finds proper solutions to the described issues at a later time, it’s good too – I will upvote them too. $\endgroup$ – 7vujy0f0hy May 2 '17 at 14:05
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In the absence of answers after 18 hours and meagre 12 views, I’ll start building my own answer – block by block.

  1. How to locate target spot on a strip at a very high zoom?
    Reverse your workflow by centering the strip on target spot first, but begin at a manageable Scale. Then multiply Scale and Position (or Position shift value if initial Position wasn’t zero) by exactly the same factor. Fine-tune Position if you can. If you can’t, undo last multiplication and redo it using a smaller factor. Repeat until you reach the desired Scale.

    • a) How to disable cropping of the output to the Render Area in the preview window?
      — (Impossible?)

    • b) How to pan a strip in the preview area?
      (Impossible?) Impossible!

  2. Why does exponential interpolation mode fail during superzoom?
    Buggy Blender? Workaround: approximate desired interpolation curves manually using multiple linear interpolation segments.

  3. How to align interpolation curves of different strips?
    No relevant functionality in Blender. Workaround: approximate desired interpolation curves manually using multiple linear interpolation segments.

Edit: 8 November 2016

  1. Leave it. I’ll sooner make it manually in C (programming language) than in Blender + StackExchange. Literally.

Interesting links

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  • $\begingroup$ I can understand your frustration with the VSE but honestly its the wrong tool for this task. What was wrong with rendering OpenGL 3D view? $\endgroup$ – 3pointedit Jun 2 '17 at 11:11
  • $\begingroup$ @3pointedit: Nothing wrong, it works perfectly. Ordinary rendering is 100× too slow for this job and I didn’t know that Blender allowed using 3D view for video rendering until you showed me how. $\endgroup$ – 7vujy0f0hy Jun 3 '17 at 3:39
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    $\begingroup$ @3pointedit: Oh, this question “was bumped to the homepage by Community♦ 16 hours ago”. So that’s why you are asking me what’s wrong 3D view rendering. I didn’t bump it though. I only haven’t selected any answer as a solution. That’s why Community♦ bumps it. I wish I could select your comment as a solution but I can’t. Someone must convert it to an answer for that. $\endgroup$ – 7vujy0f0hy Jun 3 '17 at 3:50
  • $\begingroup$ Fair enuf. I will try to work it up into a proper answer with examples then ;-) $\endgroup$ – 3pointedit Jun 3 '17 at 5:10
  • $\begingroup$ @3pointedit: There is no hurry. I already know the solution from your comment, so post it only if you want to. The question has scored 0 votes, so it’s not like you’ll earn massive reputation from answering it anyway. $\endgroup$ – 7vujy0f0hy Jun 3 '17 at 12:49

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