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#1 11-27-2012 14:48:50

Tetsuzin
Nouveau membre
Registered: 11-27-2012
Posts: 2

Images are "shaking" while moving

Hello.
(First of all sorry for my English.)

I can't explane the problem in English. Better I'll show you.

This video was made by ffDiaporama http://www.youtube.com/watch?v=r7Tq6C0T … e=youtu.be
and this video was made by KDENlive http://www.youtube.com/watch?v=S2sNb-Fe … e=youtu.be

It will be better if you get videos here: https://docs.google.com/folder/d/0BwLvf … edit?pli=1
Here you can see it in full size.

Why the image made by ffDiaporama is shaking while moving?

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#2 11-27-2012 16:42:01

Tetsuzin
Nouveau membre
Registered: 11-27-2012
Posts: 2

Re: Images are "shaking" while moving

It looks like if it is used integer numbers to calculate image size and position between two next shots.
But it's nesessary to use interpolating algorithm and float numbers.

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#3 11-27-2012 17:55:15

Sestay
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Registered: 09-19-2011
Posts: 454
Website

Re: Images are "shaking" while moving

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#4 10-28-2015 16:33:07

FlatEric
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Registered: 10-28-2015
Posts: 5

Re: Images are "shaking" while moving

Hello,

I have the same issue with ffDiaporama 2.1 64 bit.
Zoom effect performed on still images is so shaky that the resulting video is unusable. I checked the example given in the above link, sadly I cannot understand what's the difference (reframing?) between "bad" and "good" cases there... sad
Wouldn't someone just write, what's the source of the problem and how to get rid of it, please? smile

Kind regards

FE

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#5 10-29-2015 01:14:27

gerd1028
Membre
Registered: 05-09-2014
Posts: 29

Re: Images are "shaking" while moving

@Tetsuzin:
Hi, taking a look into your videos shows that the movements and zooms are not the same, so you can't compare them.
To compare the "shakiness" of a pan&zoom-action you should try it with exact the same values for startsize, position, endsize and position and doing the pan and zoom over the same amount of time.
ffDiaporama uses floats to interpolate postions and sizes, but it all ends in integers when rendering the result.

@FlatEric:
The first example (the"bad") takes the same source-area from the picture, resizes it and moves it to a new position. As both changes have to be interpolated over the time you have set for tis animation there are twice as mouch possible rounding errors as in the second (the "good") example.
In the second example the position and display-size are the same over the complete animation. Only the source-area of the picture is changed and remapped to the output size. Here onley one parameter changes over time, so less rounding errors will occure.

kind regards
gerd

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#6 10-29-2015 15:17:51

FlatEric
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Registered: 10-28-2015
Posts: 5

Re: Images are "shaking" while moving

Thank you very much!

So, as I understand, the only way to obtain smooth zooming, is to zoom without panning - i.e. with initial and final shot at exactly the same position. A little bit pity, as possibility of such a free zooming is really tempting. sad

Regards

FE

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#7 10-29-2015 15:50:10

gerd1028
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Registered: 05-09-2014
Posts: 29

Re: Images are "shaking" while moving

FlatEric wrote:

So, as I understand, the only way to obtain smooth zooming, is to zoom without panning - i.e. with initial and final shot at exactly the same position

Well, thats not really what i tried to explain.
As a hint you should take that zooming into a picture should be done in the reframing dialog by choosing a smaller source area, so you will get a smoother zooming.
With this reframed image you can do your panning as you like, but note that both effects, zooming and panning, are interpolated over the given time for the shot.
So as a result you should take this:
- zooming should be done with reframing
- for smooth panning you need to choose a proper time for the shot dependng on the distance your picture moves (you could also try it with different speed waves)

kind regards
gerd

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#8 10-30-2015 14:55:56

FlatEric
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Registered: 10-28-2015
Posts: 5

Re: Images are "shaking" while moving

Thank you.
Yes, I use the Reframing window for zooming. smile

I rendered a couple of test videos yesterday and noticed, the shaking issue is strongly dependent on the zooming speed. If the zooming factor is as big as, say, 1.25x per second (what corresponds to some 2x zoom in 3 seconds), the resizing is smooth enough that I can combine zooming and panning (i.e. zoom to/from an off centre point) and the result is fully acceptable after rendering.
Sadly, I need 15-30 sec. zooms, often with under 2x factors, for my projects ant these shake awfully. ;(

Kind regards

FE

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#9 10-30-2015 19:24:41

Sestay
Modérateur
Registered: 09-19-2011
Posts: 454
Website

Re: Images are "shaking" while moving

hello,
One alternative is to decompose Your slide with some shot to divise the effect.
here is one sample to download
https://www.dropbox.com/s/5r0q6yf005lqx … t.zip?dl=0

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#10 11-03-2015 12:37:23

FlatEric
Nouveau membre
Registered: 10-28-2015
Posts: 5

Re: Images are "shaking" while moving

Thank you,

I've seen such examples with dividing a zoom into smaller sections, I just couldn't understand the purpose. smile
It seems to work fine indeed, while the zoom is still shaky in the first 3 seconds or so, it looks pretty good for the remaining time indeed. I'll have to test this method myself.

Kind regards

FE

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#11 11-13-2015 13:18:35

gerd1028
Membre
Registered: 05-09-2014
Posts: 29

Re: Images are "shaking" while moving

Hi,
to improve the example from Sestay here's another trick:
go to the folder with the example, take the picture (vlcsnap....) ,resize/resample it to double height/width and store it under a new name.
open the ffd-file, duplicate the first slide with copy/paste. no go into the first shot of the second slide, open the reframe dialog and change the picture to the doubled one.
render the whole show and be impressed... smile

gerd

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#12 11-16-2015 23:20:31

FlatEric
Nouveau membre
Registered: 10-28-2015
Posts: 5

Re: Images are "shaking" while moving

Well... I am impressed indeed! big_smile
A lot of work and learning is still ahead of me.

Thank you!

FE

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