I am maintaining a Povray variant, that includes
JPEG input and output.  For further details,
please refer to:

http://www.imp.org/members/tech/rcast/RCast.html

Or, send me email - nig### [at] eisanetau

--
Nigel Stewart (nig### [at] eisanetau)  http://www.eisa.net.au/~nigels/
Postgrad Research Student, RMIT University, Melbourne, Australia
All extremists should be taken out and shot.

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This is extremely cool. This MUST be included into POV-Ray 3.5 or 4.0
(or at least the SuperPatch). =)


--
Anthony L. Bennett
http://welcome.to/TonyB

Graphics rendered
by the Dreamachine.

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On Mon, 28 Jun 1999 15:40:10 -0400, TonyB wrote:
>This is extremely cool. This MUST be included into POV-Ray 3.5 or 4.0
>(or at least the SuperPatch). =)

I'm generally opposed to JPEG output, because it's lossy.  Imagine
if you just finished a 3-day render only to discover that the
quality level on the output wasn't sufficient.  Who would you
blame, yourself or the guy who chose the default quality level?
I know *I* don't want that kind of support headache.  Besides,
what does JPEG gain you that you can't get with PNG?

On the other hand, using JPEG images as imagemaps, bumpmaps,
and so on is a pretty good idea.

Speaking for myself only, of course, as the current maintainer
of the superpatch.

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Ron Parker wrote:

> On the other hand, using JPEG images as imagemaps, bumpmaps,
> and so on is a pretty good idea.

 I'm even opposed to using them as input files where quality of the
image will suffer from the inherently poor quality that jpg's can
contribute to the process. I have used converted jpg images for use
as HF objects and the unwanted artifacts present in jpg's cause
unwanted height variations in the objects surface. This caused me
to to try to further process the image files to remove the artifacts
leading to other undesired effects.

 I am skeptical that using jpg's is viable when used as a standard
process. Maybe occassionaly but never on a continuous use basis.
Anyone ever hear of an animation program that accepts jpg's for
input files ? I can't recall any off hand.


Long live PNG !

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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Nigel Stewart wrote:
> 
> I am maintaining a Povray variant, that includes
> JPEG input and output.  For further details,
> please refer to:
> 
> http://www.imp.org/members/tech/rcast/RCast.html
> 
> Or, send me email - nig### [at] eisanetau
> 
> --
> Nigel Stewart (nig### [at] eisanetau)  http://www.eisa.net.au/~nigels/
> Postgrad Research Student, RMIT University, Melbourne, Australia
> All extremists should be taken out and shot.

  Not to undermine the considerable work you must have put into supporting
this image format I would like to know what your motivations were when
doing so. Is this related to reducing image file sizes for render farming
in the IMP ?

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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Um, Bryce, Ray Dream, 3D Studio MAX 2.5, Hash Animation Master are a few
programs that can use jpeg both for input and output.  If you mean for
compiling into video, isn't mjpeg about the same thing?  That's a very
common format.

I recall a thread on c.g.r.r where someone who worked on Antz claimed
they use JPEG output.

The long and short of it for me is that you will never get the
compression of JPEG out of PNG.  While LWZ compression can cut a file in
half, a JPEG file can reduce it by a factor of 10 or more without too
much artifacting.  If more projects like the IMP start to show up, some
kind of compression scheme is going to be essential.

JPEG would be an essential addition to POV-Ray.  How many people use
BMP, PGM, or PPM?  Yet they are in there and I'm sure some people find
them useful.  I haven't tested the output of this patch, but if it does
a reasonably good job I certainly hope it will find it's way into a
future version of POV-Ray.   All IMHO of course.

-Mike

Ken wrote:

> I am skeptical that using jpg's is viable when used as a standard
> process. Maybe occassionaly but never on a continuous use basis.
> Anyone ever hear of an animation program that accepts jpg's for
> input files ? I can't recall any off hand.
>
> Long live PNG !
>
> --
> Ken Tyler
>
> mailto://tylereng@pacbell.net

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> I'm generally opposed to JPEG output, because it's lossy.  Imagine
> if you just finished a 3-day render only to discover that the
> quality level on the output wasn't sufficient.  Who would you
> blame, yourself or the guy who chose the default quality level?

The poor dope who chose that setting.

> I know *I* don't want that kind of support headache.  Besides,
> what does JPEG gain you that you can't get with PNG?

Much greater compression, with no apparent loss to quality (at least from
Photoshop with max quality).

> On the other hand, using JPEG images as imagemaps, bumpmaps,
> and so on is a pretty good idea.

It's an excellent idea, especially for cross-program collaboration. Let's
say I want to check out a scene made with Max, or Lightwave, or any of the
others, and the textures are JPEG. Why the heck would I want to convert
them to TGA or PNG to use them, if they'll look the same and use more of
my precious HD space? I could just convert the scene file, and the
textures would work right away.

> Speaking for myself only, of course, as the current maintainer
> of the superpatch.

I wanted to mention that in my message. I'd hate to put more worries into
your life. I really mean that. I wouldn't want to scare you away from your
creation. =)

BTW, did you visit the site, and check out the other features? I really
like the compressed file idea. For the distribution of scenes, it is very
good. I would prefer ZIP or RAR compression, though, but that's just my
two cents.

--
Anthony L. Bennett
http://welcome.to/TonyB

Graphics rendered
by the Dreamachine.

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On Mon, 28 Jun 1999 17:28:59 -0500, Mike <Ama### [at] aolcom> wrote:

>The long and short of it for me is that you will never get the
>compression of JPEG out of PNG.  While LWZ compression can cut a file in
>half, a JPEG file can reduce it by a factor of 10 or more without too
>much artifacting.  If more projects like the IMP start to show up, some
>kind of compression scheme is going to be essential.

PNG doesn't use LZW compression (no sane person would, these days). 
It uses Huffman compression, after performing a DCT to get the data
into the frequency domain.

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On 28 Jun 1999 17:08:09 -0400, par### [at] fwicom (Ron Parker) wrote:

>I'm generally opposed to JPEG output, because it's lossy.

  Ron, I have to agree strongly with you and Ken on this one. I feel that
the official releases of POV-Ray would be compromised with JPEG output. What
people do with their images after rendering is their business but any
reduction in the number of colors should be performed as a post-rendering
process.

-- 
Alan
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TonyB <ben### [at] panamaphoenixnet> wrote:
: Much greater compression, with no apparent loss to quality (at least from
: Photoshop with max quality).

  I disagree with you. Ron is right. I very often am in the situation that
I just can't get the image I just raytraced converted to JPG without
very annoying artifacts. I convert it with higher and higher quality and
the file size grows and grows but the artifacts don't seem to disappear,
they only get fainter (but not faint enough). (This happens usually when
I have a big red object over a backround of other color.) Sometimes, however,
the JPG looks quite good.
  The point is that you can't say whether the image will look good or not
in JPG format and you absolutely can't say what quality settings are enough
for the image. A small 160x120 preview image doesn't tell you anything.
  As Ron said, you would discover after 3 days that the quality of your
JPG was definitely too low.
  Reading JPG's would be quite ok.

  If povteam ever introduces JPG output into povray (let's hope not!), I
assume that I have to add another entry to the povVFAQ: "The image that
povray calculates on screen looks ok, but when I look at the jpg it looks
very bad. Why?"

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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