Why does ZOOM effect stretch??

[deleted]

Using v 5.03.

I have a clip filmed with a webcam (AR 4:3) on the timeline and want to zoom into a section of this using the ZOOM effect keeping the AR 4:3.

This would seem straightforward. Keyframe 1 would have chequered zones to each side (black borders in the output) keyframe end zoomed in would have exactly the same chequered areas and consequenty the same black side bars but with the section selected enlarged in the frame.

Why does VP keep the sequence preview at 16:9 and distort the 4:3 area selected?

e.g. If I select restraint AR 4:3, the effect rectangle correctly resets to 4:3 outlining the image correctly.(keeping the chequered borders in the preview) But the output (sequence preview) remains at 16:9 stretching the image horizontally so as to remove the side bars.. (OK I know I can use restraint 16:9 to prevent this but why doesn't VP simply do the zoom with the selected AR keeping chequered zones and black side bars ?????

It seems a bit odd that the clip preview shows a 4:3 rectangle but the output is 16:9........

Nat

c_major_2

Hi Nat,

The Zoom effect is to fill the output with what's in the rectangle. Therefore the output will be stretched if you have a rectangle with different AR of the output.

borate

Must be missing something here. Tested a 4:3 zoom in with both PV and zoom AR set to 4:3. Then set both to 16:9. Then mixed them, both ways.

While borders varied at different settings, in no instance was the image on the timeline stretched? Circles always remained as circles.

c_major_2

To avoid stretching, the AR of the rectangle must be the same as output(preview) AR.

[deleted]

Hi Sam and Borate

" To avoid stretching, the AR of the rectangle must be the same as output(preview) AR. "

OK, I know where you are coming from.. But is the action properly implemented? This is not a complaint, just an observation. Should my 4:3 image be converted into a 16:9 image when loaded to the image bin?

Here left is an 800 x 600 pixel (4:3) image of a red circle on a yellow background. On the right I have opened the zoom effect and set AR restraint to 4:3. (Nothing else.) You can see that the thumbnail sequence (and the timeline) shows the 4:3 area stretched to 16:9 prducing red ovals.

I would have expected (intuitively) to see no change at this point as I would assume I am working with my 4:3 image.

If I now zoom in around the circle with the 4:3 rectangle (below left)...

The output zooms in OK but retains the 16:9 distortion as seen in the thumbnails . What I would intuitively expect to see is the image on the right. The AR remaining the same at 4:3 (still with chequered border (black on output) and with no distortion. I should be dealing with the original 4:3 image not the 16:9 image that VP creates from it when it was loaded.

I am most probably missing the point but it seems the thing that VP does with non 16:9 images is to load them to the bin and place them in the centre of the 16:9 frame and then make THAT the image. I know I can set the AR to 16:9 when stretching doesn't happen but as all the other AR settings produce a varying amount of distortion why have them?

Nat

c_major_2

Hi Nat,

You can change the preview AR from Options->Display->Preview Format.

The thumbnail images are always the same size and in 16:9.

[deleted]

Hi Sam

Yes, changing the AR under options...... Well, I WAS missing that point! :-) .

Doing that makes the zoom work exactly as expected for 4:3 clips. It keeps them 4:3 within the 16:9 frame when zooming without any distortion. One just has to remember to "Resize to Fit" when exported.

Nat