Section effect and keyframe question

Hackemesser wrote on 7/14/2017, 9:37 PM

Hi,

I just noticed that I can't use keyframes on Section effect. I tried to have a small section of a video following a person like a camera move. I can't make the section follow. Trying to compensate by using the size/Position effect first, then to set the section resulted in the section wandering on the screen. How can I realize a standing section following an object on camera?

Comments

johnebaker wrote on 7/15/2017, 4:13 AM

The section effect does have some restrictive behaviour as you have found, depending on the options you select it is basically either for selecting a particular section of a clip or zooming in / out to a section.

This is the method I use:-

Position the cursor at the start of the video or image
Select Size/position
Change the Width to give the required zoom level - height is automatically adjusted
Centre the now zoomed image where required - either by dragging or using Top and Left settings.
Add a keyframe if one was not created automatically - this locks the start position.
Create further keyframes to move the position of the object to follow the subject*

* I use a binary division process ie. select the end of the movement add a keyframe and centre the object, move the cursor halfway between the 2 keyframes and set the position again, repeat halving each interval between keyframes

HTH

John EB

Hackemesser wrote on 7/15/2017, 6:00 AM

I was just answering how that not would match the current needs (because the section I wanted was squared, and the original material is 16:9, then I got an epiphany. I will use or create an alpha mask of correct size that I place on the video so that I have my viewport and can still zoom and move as needed.

Thx

Scenestealer wrote on 7/15/2017, 6:02 AM

It can be done once you understand what is happening in the process of doing it.......see this lengthy post:-

https://www.magix.info/uk/forum/kf-editing-quirks-and-puzzles--1187952/#ca1311643

My solution near the bottom of page 1 and subsequent drawing up of the method by Terry & co.

Have fun!

terrypin wrote on 7/15/2017, 6:34 AM

Hi all,

Sometimes I'll settle for an intuitive no-brainer approach involving either a few export/import steps or indeed a mask.

@Hackemesser: To make sure I'm accurately following your 'following effect', could you possibly post a brief example video please?

Terry, East Grinstead, UK

Hackemesser wrote on 7/15/2017, 7:59 AM

@terrypin, imagine a camera on a tripod recording a guy at a speaker stand hopping from one leg onto the other, and you want to have his face pinned as in a picture frame. The frame/viewport should stand still in the resulting video, but the underlying source video needs to be compensated for motion.

johnebaker wrote on 7/15/2017, 11:06 AM

What you are needing is 'reverse image stabilisation'

With a bit of lateral thinking I came up with this 'unusual' method :

In your case the attachment target is the speaker's head and shoulders, you may also have to go outside the frame, however you use a mask/picture frame to hide this if required.

The comparison of the original, with section only and setion + pan is below

No manual keyframes !!!!

HTH

John EB

Hackemesser wrote on 7/15/2017, 4:58 PM

Hi, John, that looks fascinating, I will try that one next!