"Jim Holsenback" <jho### [at] hotmailcom> wrote:
> Thanks Carlo for speaking up .... I read clipka's post several times and I
> kept thinking isn't that what the 'right' keyword is for?
>
> I use this in my camera definition:
> right x*image_width/image_height

So do I, typically, but...

> then all I have to do is  +w1024 +w768 or even +w1600 +900 and bingo!!!
>
> What have I missed?

The current version of the FAQ is very clear on this, saying "DON'T!"

First time I read it, I was like, *WHAT*?? But reading through it, I noticed
that the FAQ does make some valid points, arguing that this only works with 1:1
pixel aspect ratio; and if scenes are passed on, people may not get the shot
intended by the artist because they happen to normally use a different aspect
ratio.

The "right x*image_width/image_height" approach does *not* allow you to specify
in the scene file what aspect ratio you designed it for.

The current set of .ini and scene parameters does give you all the *freedom* you
may ever need - but it is poor at specifying *constraints*.

Post a reply to this message

=?ISO-8859-1?Q?=22J=E9r=F4me_M=2E_Berger=22?= <jeb### [at] freefr> wrote:
>  Yes, I know that those resolutions aren't in the PAL or NTSC
> standards. However, those are the resolutions used by digital TV
> (whether DVD or broadcast) when targeting PAL or NTSC displays
> respectively.

Question remains whether those resolutions are intended to be shown with 1:1
pixel aspect ratio. E.g. I'd expect the 480x480 format *not* to be intended for
a square image aspect ratio, but rather for the classic 4:3 aspect ratio, using
"squished" pixels.

Post a reply to this message

"clipka" <nomail@nomail> wrote:
> "Carlo C." <nomail@nomail> wrote:
> > This time, clipka, you aren't *enlightened me immensely*.
> > For this, sorry! :-D
> >
> ....
> >
> > About "Frame Count" and "Batch Render" I am in *loud silence*, for now.
>
> I think I need to install some special codec before I can make any sense of
> these sentences: I must confess I don't have the slightest clue what you want
> to say with either of them.

The codec does not exist, this is a *bug* in my brain.
Sorry if I offended you, I have a strange (very strange) sense of humor, (but I
have a great respect for You).
I do a reset.

--
Carlo

Post a reply to this message

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

clipka wrote:
> =?ISO-8859-1?Q?=22J=E9r=F4me_M=2E_Berger=22?= <jeb### [at] freefr> wrote:
>>  Yes, I know that those resolutions aren't in the PAL or NTSC
>> standards. However, those are the resolutions used by digital TV
>> (whether DVD or broadcast) when targeting PAL or NTSC displays
>> respectively.
> 
> Question remains whether those resolutions are intended to be shown with 1:1
> pixel aspect ratio. E.g. I'd expect the 480x480 format *not* to be intended for
> a square image aspect ratio, but rather for the classic 4:3 aspect ratio, using
> "squished" pixels.
> 
	Uh, yes it is, sorry I intended to say it but it got lost in the
posting :(

		Jerome
- --
mailto:jeb### [at] freefr
http://jeberger.free.fr
Jabber: jeb### [at] jabberfr
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)

iEYEARECAAYFAknEDp8ACgkQd0kWM4JG3k9f8gCfRbhTFkbE8DhY01XZtmGB+DV8
1nEAoIGmGn169RzQUgvRlurrd0AGDTRu
=yYqX
-----END PGP SIGNATURE-----

Post a reply to this message

"Carlo C." <nomail@nomail> wrote:
> Sorry if I offended you, I have a strange (very strange) sense of humor, (but I
> have a great respect for You).

Not much of an offense received at my end. As a matter of fact, not much
received at all: Even presuming a strange sense of humor, those two sentences
still don't make any sense at all to me, so I continue to suspect a strange
(very strange) use of language instead ;)

Well, maybe a reset fixes that as well :P

Post a reply to this message

"clipka" <nomail@nomail> wrote:
> "Carlo C." <nomail@nomail> wrote:
> > Sorry if I offended you, I have a strange (very strange) sense of humor, (but I
> > have a great respect for You).
>
> ...so I continue to suspect a strange (very strange) use of language instead ;)
>

Obviously, the result of my ignorance!
Maybe because I write in *macaronic English*?
:-D

</Sorry, I close off-topic>

--
Carlo

Post a reply to this message

clipka wrote:
> I was thinking about the separation between SDL and command line parameters for
> a few things:
> 
> 
> * Image & Pixel Aspect Ratio:
> 
> There are two common practices to write scenes regarding this:
> (a) write a scene for a fixed image aspect ratio (e.g. 4:3);
> (b) write a scene for a 1:1 pixel aspect ratio.
> 
> I personally favor (b), as it always gives me an undistorted image even if I
> happen to choose the wrong image aspect ratio - or even happen to choose a
> different one later in the process.
> 
> The FAQ argues strongly against (b), obviously favoring (a), claiming that this
> makes the user aware that he chose the wrong aspect ratio because he can see
> that the image is distorted, while in the other case he may get a different
> "viewport" than intended by the scene author, without even noticing.
> 
> I insist that this argument does not hold, because the difference between the
> intended aspect ratio and the one picked for rendering may be ever so subtle,
> and the scene may not contain enough objects that hint at the originally
> intended aspect ratio clear enough. This is especially a problem with 4:3 vs.
> 5:4 aspect ratios.
> 
> I agree, however, that (b) is not an ideal solution either, as a 1:1 pixel
> aspect ratio may not always be desired.

I think that this is an issue on which there is no substitute for the 
user knowing exactly what he/she is doing.

Regards,
John

Post a reply to this message

John VanSickle <evi### [at] hotmailcom> wrote:
> I think that this is an issue on which there is no substitute for the
> user knowing exactly what he/she is doing.

If the SDL provided a way to specify the intended aspect ratio, then it would be
an easy thing to warn the user if they specify a resolution with a different
aspect ratio.

Post a reply to this message

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

clipka wrote:
> John VanSickle <evi### [at] hotmailcom> wrote:
>> I think that this is an issue on which there is no substitute for the
>> user knowing exactly what he/she is doing.
> 
> If the SDL provided a way to specify the intended aspect ratio, then it would be
> an easy thing to warn the user if they specify a resolution with a different
> aspect ratio.
> 
> 
>

#declare aspect_ratio = 4/3;
#if (abs (image_width / image_height - aspect_ratio) < 1e-6)
   #warning concat ("Invalid aspect ratio: expected ",
                    str (aspect_ratio, 1, 3),
                    " got ",
                    str (image_width / image_height, 1, 3),
                    "\n")
#end

- --
mailto:jeb### [at] freefr
http://jeberger.free.fr
Jabber: jeb### [at] jabberfr
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)

iEYEARECAAYFAknFOTQACgkQd0kWM4JG3k8swQCfe2qGwqqj0vdT0qqhYmnWfRx8
eLMAoJcutxGtP2zta7AbU/TkJ+Up84eG
=ICi9
-----END PGP SIGNATURE-----

Post a reply to this message

=?ISO-8859-1?Q?=22J=E9r=F4me_M=2E_Berger=22?= <jeb### [at] freefr> wrote:
> #declare aspect_ratio = 4/3;
> #if (abs (image_width / image_height - aspect_ratio) < 1e-6)
>    #warning concat ("Invalid aspect ratio: expected ",
>                     str (aspect_ratio, 1, 3),
>                     " got ",
>                     str (image_width / image_height, 1, 3),
>                     "\n")
> #end

Fine. But why not do this via an SDL statement? The benefits I see would be:

* No cluttering up of the SDL file with yet another macro construction that
still just does some standard thingy

* Providing an official recommended way to deal with aspect ratio that *really*
makes sense (the current recommendation has drawbacks on its own)

* Allowing for additional improvements, like:

- a command line parameter specifying the intended pixel aspect ratio that could
automatically be incorporated into this check (so e.g. specifying an intended
pixel aspect ratio of 2:1 on the command line would suppress the warning when
rendering a 4:3 scene with a resolution of 320x480 pixels) (note that such a
parameter, in turn, could some time become of interest for certain file formats
that natively support pixel aspect ratios other than 1:1)

- providing a shorthand way to set up the camera up/right/direction stuff


Honestly, I see no drawback at all associated with an explicit aspect ratio SDL
parameter. But all existing ways of dealing with aspect ratio *do* have
drawbacks - if only that they're unnecessarily cumbersome.

Post a reply to this message