.JPG vs .TGA Quality
30 messages in this thread
Rendering the exact same scene with one output to .tga and another to
.jpg (image quality set to 100%), I noticed quite a difference in
quality when viewed side by side in PhotoShop. The near vertical
lines were jaggy in .jpg and smooth in .tga. Is this common? The
manual does not state any limitations of quality in regards to .jpg.
The manual also states that the .gif format is 8 bit. The .gifs I have
rendered appear to have much more color-depth than 8 bit. 24 bit
.gifs?
You have 8 bit GIFS looking good? Not impossible. I'd like to confirm that
3DS GIF files are 8 bit only. You may have your dithering option set to yes
(DITHER-256=ON) in the 3DS.SET.
Nik
You should be able to get "visually lossless" jpg's by using less compression.
I don't use Photoshop, so I don't know how it works in that package, but in
Photostyler there is a slider. Just experiment with the compression factor.
I've used jpgs and compared them to the same tga file and could NOT find any
jpg artifacts.
John Tissavary (La Luna cie)
i think it depends on the image you are looking at. in some images i can't see
any image loss either, but on some very detailed images there is definatly a
loss of quality. i tryed an experiment with pov and raytraced 15 seconds of
animation and saved in targa form i then converted the images to jpg from
3dstudio to save space on the hard disk. i started recording the jpg images to
betacam sp and noticed quite a lot of artifacts that were not there when i
recorded the targa images.
sherwood
Sherwood:
I have not used .jpg for animations and was making an observation from still
images. Zooming out on the image looks identical, but zooming in @ 1:1 or
smaller reveals jaggy (maybe more aliased) lines on my long hard-edged objects
I've only used jpg on a few images, but they were pretty highly detailed. I
didn't notice any of the problems you stated, but I compressed them _very_
little. I'll try some other conversions just to see if I can get the
artifacting. What compression setting did you use?
thanks,
John Tissavary (La Luna cie)
the compression i used was 100 % in 3dstudio. which is the only
setting you should use for quality images. i don't like to use any
compression at all , i like to keep the images at 100 % targa
quality, but if you HAVE to use jpg or any other compression meathod
then 100% quality is a must expecialy for jpg.
we are in a business that requires the best quality in image output to
compete in the animation market here with SGI,WAVEFRONT, ECT… being
the goal in quality we want to get to.
WHY would we want degrade the output just to save time in the final
output phase?
the answer is NO we do not! so for previews its fine to go to the PAR
for a "yes/no" on the animation, but i would never NEVER go to tape
for final output with the PAR. for the simple fact the you do lose
somthing no matter how small in compression that will in some way
impact you final animation. i for one will not take that chance.
You might not see it on YOUR setup, but beleave me it does show up
(jpg) on other studio setups that i have been to! and its very sh*ty
to see.!
i have ordered 2 pars just for previews but because it uses jpg
compression and at least i can see the difference, jpg is out for me
for final output to tape – i will/am still using frame by frame to
betacam-sp (bvw-75 ) for final output for the client.
call me safe….. but when a 20,000.00 dollar contract is on the line
i will beat up my machines before i beat my client every time<GGGG>
sherwood …. *** my too cents worth ***…. animations
Why did you post this to me? I use an Abekas A66 out to SP, Digital,
and D1, and have always maintained that no JPG device could possible
compete with it. I do not believe the PAR would be acceptable for a
large part of my clientel either.
John:
>>You should be able to get "visually lossless" jpg's by using less
compression.<<
I set the compression to "0" for maximum image quality. With no compression, I
saw a noticable difference. I also own PhotoStyler and the compression slider
works only when you save as a .jpg., not when opening a file to view.
Mike
Mike
I save a particular image as both a .tga and .jpg, then compared them,
particularly checking the edges. I couldn't find a difference.
John Tissavary (La Luna cie)
John,
me too. Saving at max quality, minimum compression, I'd zoom in 16x and try to
spot different pixels. I spotted a couple that had changed but not adversely.
There is a nice couple of articles on image compression in the March
issue of New Media magazine, if that interests you. One is called
"Crunch Time for Digital Video" and has some pictures comparing some
different compression artifacts. The second is technical: "How
Codecs Work" and is most interesting. (This issue also reviews a few
object orientated paint programs includin Altimara Composer.) FWIW.
PS: Have you been living dangerously lately?
I read the articles you mentioned (I'm also a CG magazine addict) –
very interesting and in-depth on compression types. Altamira Composer
got good marks for it's capabilities – I beta tested it but never got
a free copy at the end 🙁 I probably didn't give them enough feedback
or something. I have the 0.7 version but it expires every 2 months or
so and I have to re-install if I need to use it. I'd probably buy it
if I did a lot of that kind of work, (or hiresQFX which beats it
hands down on speed), so it might be a tough choice. Meanwhile, I
soldier on with my own copy of Photostyler and Photoshop for Windows
at my client's.
>> PS: Have you been living dangerously lately? <<
Certainly not! But I've been skydiving fairly regularly <g>. The wife
and I am debating taking part in the annual "Grand Canyon rim-to-rim
and back in 24 hours run/hike". That should be a huge physical
challenge and it would probably put me out of action for a week or 2.
Am I man enough to try it? No, but I believe I will anyway <g>. I
love a challenge.
I bought the Altamira at Siggraph and got the final, and MAN is it
powerful. So much so that much of it is way beyond my ability to do
amazing things with just casual occasional use. I need to immerse
myself in it for a while or wait for a good book full of tutorials.
The skydiving is too much for me! However, my oldest son is about
done with college ($$$) so I'm thinking about getting back into
flying again – drop by and I'll take you up and throw you out. <g>
JKJ,
>> Altamira …. I need to immerse myself in it for a while <<
It's very powerful but it requires a good sized project and in-depth immersion
to make full use of it's features. Lots of RAM is essential as I found out to
my detriment 🙁 I did a 14 layer composition with skydivers and some NASA
photos. I'm hoping to get it on the cover of a skydiving magazine one day –
it's called spcdiv.jpg in the what's new library, FWIW.
>> getting back into flying again – drop by and I'll take you up and throw you
out. <g> <<
A great offer! My favourite pursuits, ever since I was a child,
involved jumping off, out of, or into things. Base jumping is
probably in my future, I'd think, and the Norwegian fjords are
supposed to be perfect for this 🙂
BTW, I'll probably be seeing you soon. AlanI says you're coming to
the Southland soon and since he and I are practically neighbours I'll
try and pop over to share a pint and a good yarn <g>.
>>base jumping…
Yikes!!! How do I get written into your will? I'll check out the SPCDIV.JPG.
I just had a distinct mental image of animating my space shuttle upon reentry,
with it inverting, the bay doors opening over the Baja, and Martin jumping out
with a bungee. I think I need to get more sleep…
I am definately hoping for a SoCal excursion in mid-May. Whether it will
happen depends partially on the state of a particular project I'm working on
(which will pay for most of the trip). If that falls thru, I've got a couple
of other tricks sleeved which may work out. I would certainly enjoy an English
Tea and a good yarn.
J K J
JKJ,
>> I am definately hoping for a SoCal excursion in mid-May. <<
looking forward to it 🙂
>>…GC rim-to-rim and back in 24 hours…
YOU are INSANE!
– G
>> YOU are INSANE! <<
not so fast! I've booked YOU for the race too! If you're not up to it
we could probably arrange a chopper <g>.
Actually, I do have this strange tendency to want to test my limits
against natural adversities. It's probably just a reaction to my
sedentary occupation as I really don't want to get fat and
complacent. BTW, there will quite possibly be an "Escape from
Alcatraz" reprise this year, since I want to land in the right place
this time <g>.
Finally and to keep me legal, I do think .tga files are more
appropriate than .jpg in certain instances <g>.
I'll be there for you in spirit (with moral support :-).
And yes, I do think .tga files are more appropriate than .jpg's in certain
instances. <g>
– G
Hi John-
How are you viewing the two files? I am zooming in on a particular area of both
files in PhotoShop and then putting the windows side-by-side. A difference is
there. Perhaps it may be the way PhotoShop deals with JPEG's. I will try
viewing in PhotoStyler to see the results (When I make enough room on my hard
drive to reload it). Is there a way to view both files in 3DS? I can't think of
a way short of mapping the images to an object.
I re-rendered the two files to be sure of my set-up settings…..same results.
Viewing in Windows, I am using 8800x600x24 display driver.
Mike
First of all, I would NEVER render a .jpg from 3D Studio. That way I
don't have a solid, robust image to work with from the start. What I
am talking about was rendering a tga, then copying it to .jpg for
transportation purposes (modem to service bureau for hard output).
This way I can do all my image editing in .tga format, then just save
it as a .jpg. I saw absolutely no difference in the two images side
by side.
I would not recommend using a .jpg as a start because it just does not
contain as solid information as .tga.
<<I would not recommend using a .jpg as a start because it just does
not contain as solid information as .tga.>>
Thanks for the insight. I have been using .jpg because it does not eat
drive space like the .tga. When I make custom maps in other programs
I have been saving as .jpg (the last time I looked my map directory
was hovering around 22 meg!). I never saw any difference whatsoever
before this particular file. Lots of self-illum, gradient opacitys,
shiny maps, and many other things the mat.editor can throw out.
Do not quite understand the "solid information" line, but am ready to
follow your advice. I only get to use 3ds after my "real job" and
appreciate all the great advice here on the forum from you regular
users.
"Solid information" was a feeble attempt at describing the lossy quality of
jpg's, and that they are not good image files to work with, but make ok final
output as long as they are low enough to be visually lossless.
have fun,
John Tissavary (La Luna cie)
I guess I need to qualify that I don't use 3DS's JPG output option,
but if I have a large file for still output, I'll render it as a
.tga, then convert it to jpg in Photostyler, experimenting with
compression to make sure I can find no artifacts.
I also don't use .jpg for any animated output. My stills are almost always
storyboards.
John Tissavary (La Luna cie)
For things like texture maps, .jpg's are great. And for scenes that
don't have any really smooth gradients, they're work pretty well
(even though they don't have an alpha channel). But for anything
with a smooth gradient, the jpeg code in 3DS will add some color
quantizing artifacts… In those cases, definitely use .tga or tif.
John,
FWIW, my experience with JPG is with minimum compression, the images
look identical. If you alter the brightness/contrast or tint, or change the
scale, the image turns to trash.
Cap
I agree. I use .jpg only as a means of getting files from one place
to another when they don't have an Exabyte tape drive. That way I
can modem stuff or put them on floppies, and actually not spend all
day and all my money doing it. I'm sold on .jpg's as a
transportation medium if I can't use Exabyte.
The only *major* difference I've noticed when using custom low
compression is actually in areas of the image which have expanses of
*CONSISTENT* color, as opposed to gradients or colors constantly
changing from pixel-to-pixel. Think it's something to do with the way
the algorithm "fools" your eye.
Interesting. I did check the solid areas, but not as intentsely as
the edges and gradients. I'll give a closer look next time.