Non-square pixels in rendered stills?

Support Synfig related help
1

Hi there

I am trying to use synfig to create titles for videos. My final target is an overlay on an existing DV PAL 16:9 clip.

In synfig I create a background that is some variant of 16:9, e.g 800x450. I then want to render a number of frames from this in 720x576 with 16:9 aspect. I can’t figure out how to do this. Instead I render the 800x450 frame, and resize these to the pixel size of DV PAL: 720x576, which has a pixel aspect ratio of about 1.4222. And overlay them on the video. However, the resize steps obviously is suboptimal, and makes the images slightly fuzzy.

What I want to do, is to avoid the resize step, and have synfig output to stills, that has an (possibly “faked”) pixel aspect that matches the 720x576 pixels in 16:9 format. Intuitively, what I am looking for, is for synfig to draw an “egg” instead of a circle, on the rendered 720x576 stills.

I have tried to fiddle around with the options for a project and the rendering options, but I have not succeded in changing anything but the resolution and the canvas size - which is kind of useless.

From the options it seems it should be possibly, but I can’t figure it out.

Another option I have just realised I might use is to use a background of 720x576, and then apply a stretch layer, with a vertical stretch of 70% (70pt). This makes the rendering OK. However, this means that I have to work on a squeezed image in synfig studio, which is really not what I want…

Any help appreciated.

Mads Bondo Dydensborg

2

OK, got the solution from AkhIL on irc:

  1. Use square pixel when you edit it in synfig (1024x576 for 16:9 and 768x676 for 4:3)
  2. Just before rendering, in canvas property->Other->Locks and links, set checkboxes for Image Aspect and Image Span, and uncheck Pixel Aspect (madsdyd: This is possibly the options dialog for File|Render, at least for me)
  3. Change back to the Image settings
  4. Change resolution to 720x576
  5. Render

That should produce stills with the right “pixel aspect”. When viewed on the PC using square pixels, a circle will appear as an egg. When viewed on a widescreen TV, the circle will become a circle.

Many thanks to AkhIL from #synfig on irc.freenode.net.

Mads Bondo Dydensborg