POV-Ray : Newsgroups : povray.object-collection : 3D Loop : Re: 3D Loop Server Time
24 Oct 2021 02:02:42 EDT (-0400)
  Re: 3D Loop  
From: clipka
Date: 26 May 2015 12:20:04
Message: <55649d34$1@news.povray.org>
Am 26.05.2015 um 17:53 schrieb Le_Forgeron:

>>> Changing the default right vector (even to something like
>>> image_width:image_height ratio, assuming square pixel
>>> everywhere) would only have one sure effect: break every
>>> historical scenes. Without providing 100% satisfaction to all
>>> users. Better not move.
>>
>> I totally agree - except when it comes to defaulting to square
>> pixels, which /does/ make sense nowadays; after all, that's what
>> any reasonable image handling software defaults to as well if the
>> input image material provides no embedded resolution information.
>>
>
> Yep... until you want to make a DVD (none of NTSC and PAL have square
> pixels...)

(Actually NTSC and PAL don't have any pixels at all; they just have 
contiguous scan lines with a specified maximum signal frequency. But I 
guess you're right about NTSC/PAL compatible DVD content. ;))

Even so, I'd expect that even contemporary professional or 
semi-professional video editing software will presume input images to 
have square pixels - unless explicitly told otherwise by the image 
header, the user, or the software administrator.

Also, when you export a PAL or NTSC DVD movie sequence as a series of 
images, I'd expect any sane video handling software to write them in a 
square-pixel format, even when additional resolution information is 
written to the image header. (Again, unless told otherwise of course)


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