#251 rescale parameter

[Fred Périé]

from kdenlive I created a script and added the rescale parameter
I tried
rescale=bilinear
rescale=bicubic
rescale=spline
rescale=sinc
rescale=lanczos

I extracted the first image of each video file generated and compared them
I can clealy see the difference between bilinear and bicubic
but no difference between the higher interpolation methods

in fact he files are identical
$ diff bilinear.png bicubic.png
Les fichiers binaires bilinear.png et bicubic.png sont différents
$ diff spline.png bicubic.png
$ diff lanczos.png bicubic.png
$ diff sinc.png bicubic.png
f@Ozu ~/Images $ melt -version
melt 6.5.0
Copyright (C) 2002-2016 Meltytech, LLC
http://www.mltframework.org/
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[Dan Dennedy]

This depends on what is in your .mlt file. I see you are rendering to 1920x1080. The spline, since, or lanczos options only affect scaling from a source that is a different resolution. If the .mlt includes affine, for example, that also interprets rescale, then it does not implement anything other than nearest, bilinear, and bicubic. Are your sources different than 1920x1080?

[Fred Périé]

Thanks.

If I undestood well pan and zoom (kdenlive) is done by affine in melt. if
the only options in affine are nearest, bilinear, and bicubic, this is
consistent with what I noticed.

Regards
Fred

2017-01-06 5:44 GMT+01:00 Dan Dennedy ddennedy@users.sf.net:

This depends on what is in your .mlt file. I see you are rendering to
1920x1080. The spline, since, or lanczos options only affect scaling from a
source that is a different resolution. If the .mlt includes affine, for
example, that also interprets rescale, then it does not implement anything
other than nearest, bilinear, and bicubic. Are your sources different than
1920x1080?

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• [bugs:#251] https://sourceforge.net/p/mlt/bugs/251/ rescale parameter*

Status: open
Group: unknown
Labels: upscaling
Created: Thu Jan 05, 2017 12:07 PM UTC by Fred Périé
Last Updated: Thu Jan 05, 2017 12:07 PM UTC
Owner: nobody
Attachments:

• salle2_test1_bicubic.sh
  https://sourceforge.net/p/mlt/bugs/251/attachment/salle2_test1_bicubic.sh
  (477 Bytes; application/x-shellscript)

from kdenlive I created a script and added the rescale parameter
I tried
rescale=bilinear
rescale=bicubic
rescale=spline
rescale=sinc
rescale=lanczos

I extracted the first image of each video file generated and compared them
I can clealy see the difference between bilinear and bicubic
but no difference between the higher interpolation methods

in fact he files are identical
$ diff bilinear.png bicubic.png
Les fichiers binaires bilinear.png et bicubic.png sont différents
$ diff spline.png bicubic.png
$ diff lanczos.png bicubic.png
$ diff sinc.png bicubic.png
f@Ozu ~/Images $ melt -version
melt 6.5.0
Copyright (C) 2002-2016 Meltytech, LLC
http://www.mltframework.org/
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

---

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[Dan Dennedy]

Yes, the Kdenlive Pan & Zoom effect uses the MLT affine filter.