Zoom is stuttering


I tried a simple zoom-in/on with a text and have got an animation with “wobbling” characters.

See the attachment: zoom_test.sifz (858 Bytes)

I’ve learned, that such an effect has already been reported in 2007 youtube.com/watch?v=Y70SKP4ot0E but I found no remedy so far.

The same effect happend, when I tried it for an png-image (showing the text) instead, not for the individual characters of course, but for the hole image the zoom wasn’t smooth and stutters.

I tried to increase quality, resolution and fps. No change.

What I’m doing wrong?

Thanks in advance for the help!

PS.: I’m using synfigstudio_0.64.0-20130509.master.8_amd64.deb on Ununtu 12.04 LTS with all patches applied.

Here is an example using an image. As one can see in the rendered movie, the upper and left edges of the image aren’t moving smoothly: Szene_003.sifz (865 Bytes)

I can’t open the files now, but I bet that the png image is not included in the last attachment. Can you please provide the complete files to produce the flickering with the png image? A zip of the folder containing everything would be enough.

For wobbling text, can you try the Cairo render. I think that Cairo does a better job on that.

Hi Genete,
thank you for your response :slight_smile:

Here is a zip-file including the sifz, the image and the exported animation (ffmpeg, XviD/AVI, 2k bps): Szene_003.zip (465 KB)

How can I use Cairo for an XviD/AVI animation?



You only can use Cairo for png sequence output. Use Synfig Studio 0.64.0 and select cairo_png as target in the render dialog.

Later, use a video editor to convert the png sequence into your favorite video format.

Cairo rendering doesn’t help. It’s not the same, but stuttering as well. I wonder, if there is some problem with rounding numbers somewhere in the algorithm. If I can find some spare time, I’ll check the source code for that. But this sounds for some heap of digging code. Looks not very promising for me.

Thanks anyway.

I’m sorry for the late response.
I’ve reproduced the problem with the normal renderer and I can confirm that the stuttering doesn’t happen with Cairo. Just do a preview and check Cairo [1] render in the preview dialog and you’ll see.

The reason is not the zoom layer but the Import Image layer that for some reason, in normal renderer does a rounding to int for the image size when rendering it. It is not made by Cairo and that explains the differences.

And yes, it is a bug. It shouldn’t happen.

[1] I’m using development version (the upcoming 0.64.1 version)