wwp@yahoogroups.com:
Re: Image width / 96 and height
Dave 360texas.com 2005-Sep-28 22:18:00
I agree. decisions, decisions.
I did have a read of the URL. I returned more confused. I think
your answer of cubed face size is of great help. It would be
interesting if we could do a hyper-jump from what the information in
the URL link.. to PTgui and pano2qtvr notation. Ptgui uses alot of
the information in the URL. Pano2qtvr uses cube face dimensions. I
do realize that cylinder results are quite different than those who
shoot 4 with a Sigma 8. I hope there is simple translation for the
spherical imaging group?
Perhaps your tile size examples of "768x768 (less ugly) for the
small panorama, and 1480x1480 for the fullscreen one" will help us.
Thank you.
dave [at]360texas [dot] com
--- In #removed#, Markus Altendorff <#removed#>
wrote:
> Dave 360texas.com wrote:
> > So what I am gathering.. for a proper image width should
> > be divided by 96, and be a 2:1 ratio.
> >
> > This set width numbers are divisable by 96 and /2 for
> > 2:1. Of course we have to watch the final MOV file size
> > too...
>
> Note that this width rule only applies for Cylinders - if
> you're using a 2:1 ratio, most likely it's not cylindrical,
> but spherical! There's a very thorough explanation of the
> rules and resolution calculations on the homepage of Ken
> Turkowski:
>
> http://www.worldserver.com/turk/quicktimevr/panores.html
>
> Personally, i use a cube tile size of 640x640 (ugly) or
> 768x768 (less ugly) for the small panorama, and 1480x1480
> for the fullscreen one. This equals a 4648x2324 spherical
> panorama. Note that the cube face size is NOT simply the
> spherical circumference divided by 4 - you've got to factor
> the projection from spherical to cubical into it. Imagine
> putting a ball in a box - the box' circumference will be
> larger than the ball's.
>
> My line of reasoning when i pick a cube face size is:
> - the smaller the image is, the higher the JPG quality can
> be set while maintaining a fixed file size
> - vice versa, the larger the image is, the less JPG quality
> can be used.
>
> BUT:
> - the larger the image is, the less noticable the JPG
> compression "residue" will be (usual JPEG blocks are 8x8),
> so i may get away with choosing less JPG quality
>
> BUT (2):
> - the larger the (uncompressed) image, the less smooth it
> will pan in the browser (if playback buffer memory becomes
> too tight)
>
> Decisions, decisions...
>
> -Markus