Quick Stereoscopic 3D tests

Discuss the ZGameEditor Visualizer plugin for FL-Studio.

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StevenM
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Quick Stereoscopic 3D tests

Post by StevenM »

There is a problem with the aspect ratio after YouTube processes the 3D video.

The 3D video gets squashed from top to bottom.

See Here:

http://www.youtube.com/watch?v=TC0ebjuaarE

In order to fix this both sides need to be squashed horizontally by 50%. I had the 3D head model, So I was able to do this artificially by stretching the 3D model 50% up on the Y axis.

http://www.youtube.com/watch?v=oaQeCpgY7y8

Exported at 1280x720 seem to work ok.

I also seen some people were uploading 1280x360 and using some kind of swap option, but that produces bad results. WMV doesn't support aspect ratios like that either.

This could be difficult, is there a way to scale the entire canvas up 50% vertically and and have zoom out?

Parameter sliders for the user to do this manually would work.

I have an offline 3D player and that works fine with the way things export now. I wouldn't want it to export squashed side by side for YouTube all the time.
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VilleK
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Post by VilleK »

I was hoping YouTube automatically would use the correct aspect ratio. If your standalone player does that then it must be possible. Btw, what player do you use?

Some videos use the "yt3d:aspect" tag, did you try that?
StevenM
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Post by StevenM »

VilleK wrote:I was hoping YouTube automatically would use the correct aspect ratio. If your standalone player does that then it must be possible. Btw, what player do you use?

Some videos use the "yt3d:aspect" tag, did you try that?
Yes, I tried. It doesn't fix. It's actually a pretty comon problem when I looked it up.

This offline player works very well results have been really good with this so far.

http://www.3dtv.at/Downloads/Index_en.aspx

Free for 30 days. Playback time limit afterwards.
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VilleK
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Post by VilleK »

I think I understand how it works now.

When ZgeViz renders to video at a selected resolution in stereoscopic mode it will actually render two images at half width each.

So for instance: User chooses export at 640x480. ZgeViz renders two images at 320x480 and put them next to each other.

This of course changes the aspect of the video. 640x480 is 3:4 but 320x480 is 2:3. Aspect ratio calculator: http://andrew.hedges.name/experiments/aspect_ratio/

For this video I added the tag yt3d:aspect=2:3 and it now displays correctly: http://www.youtube.com/watch?v=7oBLEZtKKVI

It would be better to render two images at full resolution but then there is the problem of opengl having difficulties with rendering images larger than the desktop size (it can only be done using extensions). Also the video files will be huge. Another option would be to half both width and height resolution for the images during export because that will keep the aspect ratio intact. That is much easier to implement but perhaps not what the user expects?
StevenM
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Joined: Thu Jan 20, 2011 10:03 am

Post by StevenM »

OK - I understand how the aspect ratio tag works now.
changed this to "yt3d:aspect=8:9" - which makes it 640x720.

http://www.youtube.com/watch?v=TC0ebjuaarE

This resolution looks ok too. Maybe, just this is fine?

Edit: portrait resolution with borders - probably not good. Looks ok here because of a black ground.
It would be better to render two images at full resolution but then there is the problem of opengl having difficulties with rendering images larger than the desktop size (it can only be done using extensions). Also the video files will be huge.


there are a lot of technical hurdles. Rendering videos of that size could take a very long time too. Also, I'm pretty sure there is a problem with WMV file format. I don't think it allows custom aspect ratios.

Another option would be to half both width and height resolution for the images during export because that will keep the aspect ratio intact. That is much easier to implement but perhaps not what the user expects?
I think this option is good. I have seen quite a few 3D Youtube videos that use this method to fix the aspect ratio too. Exporting the Full size side by side might render the best results, but it is pretty cumbersome to work with. Do you think there should be a way to toggle YouTube compatibility off/on?

EDIT: One good thing about this though is the user can just upload and add yt3d:enable=true, no technical problems, and get the aspect ratio they would expect.
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