A Photography forum. PhotoBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » PhotoBanter.com forum » Digital Photography » Digital Photography
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

What program is best at JPEG compression?



 
 
Thread Tools Display Modes
  #22  
Old July 23rd 07, 06:59 PM posted to rec.photo.digital,alt.comp.periphs.dcameras
Bill Tuthill
external usenet poster
 
Posts: 361
Default What program is best at JPEG compression?

In rec.photo.digital Fed-Up-With-Corel wrote:

Unless you use an editor that is able to edit JPEG files
without recompressing the whole image every time you save it.
PhotoLine 32 www.pl32.com is the only one I know of that
allows you to edit a JPG file where the only data that gets
put through the compression routine again when you save it
is that which you specifically edit or change from the original.


JPEG Wizard also did/does this to a certain extent.

Is PhotoLine32 almost equivalent to Photoshop in functionality?
It has 32-bit and LAB/CMYK support, but only costs 59 Euros.
The online tutorial does not seem complete.

  #23  
Old July 24th 07, 08:31 AM posted to rec.photo.digital,alt.comp.periphs.dcameras,alt.www.software
imbsysop
external usenet poster
 
Posts: 18
Default What program is best at JPEG compression?

On Mon, 23 Jul 2007 14:40:31 GMT, "CSM1"
wrote:

"imbsysop" wrote in message
.. .
On Thu, 19 Jul 2007 09:57:39 -0500, "CSM1"
wrote:

wrote in message
egroups.com...
Are some graphics programs better than others for compressing JPEG?
A friend swears that Image Ready is the best for getting the
smallest file with same quality.
But I see a few companies have made utilities purely for
compressing pictures, and claim they obtain better
compression than the top tier graphics programs.
I presume there are different numerical routines used by
different companies in their software, but I would guess
maybe 5% variation in file size at best.
I know there was a comparison done several years ago,
but the website with the pictures seems to be kaput.
(www.imagecompress.com ?)
Is there a recent comparison of different programs to see
who offers the best compression?
That is, best quality for same size, or smallest size
for same quality.


Jpeg compression is a big subject, since JPEG is a lossy compression
scheme,
there are always trade offs. File size vs. amount of compression and
artifacts.

The better Graphic programs give you a choice of the amount of compression
used.
The de facto best Photo editor it Adobe Photoshop. The full version is
about
$650 or $150 for the upgrade.

Photoshop Elements is a consumer grade Photo editor that costs much less
money ($100) and does most of what Photoshop CS does.
http://www.adobe.com/products/photoshopelwin/


I've always thought jpeg and its compression algorithm were subject to
a general standard and not to any program makers' fantasy ..????


Have you read the JPEG specification?
http://www.w3.org/Graphics/JPEG/jfif3.pdf


yes I did but did you ?

quote
"...
JPEG Compression
Although any JPEG process is supported by the syntax of the JPEG File
Interchange Format (JFIF) it is strongly recommended that the JPEG
baseline process be used for the purposes of file interchange. This
ensures maximum compatibility with all applications supporting JPEG.
JFIF conforms to the JPEG Draft International Standard (ISO DIS
10918-1).
The JPEG File Interchange Format is entirely compatible with the
standard JPEG interchange format; the only additional requirement is
the mandatory presence of the APP0 marker right after the SOI marker.
Note that JPEG interchange format requires (as does JFIF) that all
table specifications used in the encoding process be coded in
the bitstream prior to their use...."
unquote

  #24  
Old July 24th 07, 03:46 PM posted to rec.photo.digital
Matt Ion
external usenet poster
 
Posts: 583
Default What program is best at JPEG compression?

David J Taylor wrote:
imbsysop wrote:
[] I've always thought jpeg and its compression algorithm were subject to
a general standard and not to any program makers' fantasy ..????


There is a standard, but with a large number of different choices. For
example, you can change the colour resolution relative to the luminance
resolution. How different programmers interpret "95% quality" is up to
them, so it's entirely possible that different programs will better suit
different images.


Ultimately, I think that's the key: "different programs will better suit
DIFFERENT IMAGES". There is no one "best" or "worst" implementation
because how "well" a particular encoding scheme works will depend on the
specific image it's dealing with.
  #25  
Old July 24th 07, 04:13 PM posted to rec.photo.digital
James Silverton
external usenet poster
 
Posts: 155
Default What program is best at JPEG compression?

Matt wrote on Tue, 24 Jul 2007 14:46:19 GMT:

MI David J Taylor wrote:
?? imbsysop wrote:
?? [] I've always thought jpeg and its compression algorithm
?? were subject to
?? a general standard and not to any program makers' fantasy
?? ..????
??
?? There is a standard, but with a large number of different
?? choices. For example, you can change the colour
?? resolution relative to the luminance resolution. How
?? different programmers interpret "95% quality" is up to
?? them, so it's entirely possible that different programs
?? will better suit different images.

It is an interesting question as to which is the best general
method since *most* people won't want to use more than one
technique. It does beg the question of what is wanted. Is the
"best" method that which produces the smallest result or some
sort of compromise among size, resolution and color resolution
etc.?


James Silverton
Potomac, Maryland

E-mail, with obvious alterations:
not.jim.silverton.at.verizon.not

  #26  
Old July 24th 07, 08:31 PM posted to rec.photo.digital,alt.comp.periphs.dcameras
Mike S.
external usenet poster
 
Posts: 36
Default What program is best at JPEG compression?


In article , Bill Tuthill wrote:
In rec.photo.digital Fed-Up-With-Corel wrote:

Unless you use an editor that is able to edit JPEG files
without recompressing the whole image every time you save it.
PhotoLine 32 www.pl32.com is the only one I know of that
allows you to edit a JPG file where the only data that gets
put through the compression routine again when you save it
is that which you specifically edit or change from the original.


JPEG Wizard also did/does this to a certain extent.


AFAIK only on selective compression areas, or limited area processing such
as red-eye removal. Then again, it really isn't an editor, per se; more
of an image manipulator and processor. I'd imagine if you were to make any
global change, such as color balance adjustment, that would require
reprocessing in order to save the modified image.





  #27  
Old July 24th 07, 09:42 PM posted to rec.photo.digital,alt.comp.periphs.dcameras
HEMI-Powered
external usenet poster
 
Posts: 591
Default What program is best at JPEG compression?

Mike S. added these comments in the current discussion du jour
....

Unless you use an editor that is able to edit JPEG files
without recompressing the whole image every time you save
it. PhotoLine 32 www.pl32.com is the only one I know of that
allows you to edit a JPG file where the only data that gets
put through the compression routine again when you save it
is that which you specifically edit or change from the
original.


JPEG Wizard also did/does this to a certain extent.


AFAIK only on selective compression areas, or limited area
processing such as red-eye removal. Then again, it really
isn't an editor, per se; more of an image manipulator and
processor. I'd imagine if you were to make any global change,
such as color balance adjustment, that would require
reprocessing in order to save the modified image.

Until I started reading posts in this thread, I was unaware that
there are ANY programs that can alter a JPEG without having to
recompress the entire image. I can see your point about a
localized change like the small parts of an image that had red
eye removed, but I would think that you are right that any change
that affects literally every pixel in the image, which would
happen in your example of changing colors, would require a
complete recompress.

I've stayed out of this discussion because it doesn't really
apply to my work, but I would like to just offer a comment. Like
most people, I save the unedited images files from my camera
should the need arise to completely redo a picture. One reason to
do that for me, since I print very little, would be to create one
with more PPI. But, if I discover a minor defect in one of my
finished JPEGs, I will re-edit it, but save it with the 1-100
compression set one lower than the first time, as judged by the
real-time file size. Then, as always, I inspect the final
compressed image on my HD by looking at it full size to see if
I've accidently introduced any damage at all from the re-edit.
Luckily, or maybe I just have low standards, I fine very, very
few that have enough damage that I can't fix it by altering the
compression, Chroma subsampling, or maybe rubbing some blotches
with a mild soften brush.

--
HP, aka Jerry
  #28  
Old July 24th 07, 10:03 PM posted to rec.photo.digital,alt.comp.periphs.dcameras
Mike S.
external usenet poster
 
Posts: 36
Default What program is best at JPEG compression?


In article ,
HEMI-Powered wrote:

Until I started reading posts in this thread, I was unaware that
there are ANY programs that can alter a JPEG without having to
recompress the entire image. I can see your point about a
localized change like the small parts of an image that had red
eye removed, but I would think that you are right that any change
that affects literally every pixel in the image, which would
happen in your example of changing colors, would require a
complete recompress.


Well, they _claim_ that they do so, but I have not been obsessive enough
to try to verify it. Conceptually, though, I don't understand how Huffman
encoding would even allow you to change _any_ pixel values in a bitmap and
not have it require changing the rest of the compressed data.

  #29  
Old July 24th 07, 10:17 PM posted to rec.photo.digital,alt.comp.periphs.dcameras
Bill Tuthill
external usenet poster
 
Posts: 361
Default What program is best at JPEG compression?

In rec.photo.digital HEMI-Powered wrote:

Until I started reading posts in this thread, I was unaware that
there are ANY programs that can alter a JPEG without having to
recompress the entire image. I can see your point about a
localized change like the small parts of an image that had red
eye removed, but I would think that you are right that any change
that affects literally every pixel in the image, which would
happen in your example of changing colors, would require a


So I guess you know that Irfanview, among other applications, can do
lossless rotation and flip, although it truncates to 8-pixel boundaries
so it's only truly lossless with 8x pixel dimensions.

To guess JPEG parameters, you can obtain the "jpegdump" program
by Allan N. Hessenflow. When saving an edited JPEG, the destruction
is minimal if you save with the same quality and chroma subsampling.

As the JPEG FAQ says, destruction is worst when resaving with slightly
different parameters at the higher quality values, counterintuitively.

P.S. Thanks for your comments in the PaintShopPro thread.

  #30  
Old July 24th 07, 10:42 PM posted to rec.photo.digital,alt.comp.periphs.dcameras
HEMI-Powered
external usenet poster
 
Posts: 591
Default What program is best at JPEG compression?

Mike S. added these comments in the current discussion du jour
....


In article ,
HEMI-Powered wrote:

Until I started reading posts in this thread, I was unaware
that there are ANY programs that can alter a JPEG without
having to recompress the entire image. I can see your point
about a localized change like the small parts of an image that
had red eye removed, but I would think that you are right that
any change that affects literally every pixel in the image,
which would happen in your example of changing colors, would
require a complete recompress.


Well, they _claim_ that they do so, but I have not been
obsessive enough to try to verify it. Conceptually, though, I
don't understand how Huffman encoding would even allow you to
change _any_ pixel values in a bitmap and not have it require
changing the rest of the compressed data.

That's what I always thought, until I read about these magic
programs in this thread. I'm no expert and not interested in
trying to verify the veracity of the claims because my work isn't
such that would be helped. But, in keeping with my general
philosophy that learning is a life-long endeavor, if somebody has
invented a better mouse trap, I'm interested enough to at least
listem.

Prevailing wisdom, and we all know the limitations to that, says
that the way the JPEG standard is actually implemented in
software always results in the entire pixel map being considered
in a re-compress/re-save. That said, it doesn't necessarily
follow that every damn pixel gets mangled by the process, which
is why - I think - that my personal experience is that minor
edits/re-saves done judicially can avoid the usual hysterical
"you're going to damage the image!" claims. But, like your
comments, I've not done scientific tests of my belief nor have I
done the pathological examples of half dozen edits/resaves.

--
HP, aka Jerry
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Better JPEG program - minimized JPEG degredation Paul D. Sullivan Digital Photography 14 January 30th 07 08:34 PM
best compression for saving photos in jpeg? Brian Digital Photography 14 December 24th 04 01:59 PM
JPEG compression James Ramaley Digital Photography 14 October 26th 04 01:41 AM
Ron Baird - Kodak DX7630 high jpeg compression Ron Baird Digital Photography 9 August 24th 04 03:19 PM
JPEG compression options -- can anybody explain? Beowulf Digital Photography 3 August 4th 04 02:17 AM


All times are GMT +1. The time now is 02:11 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 PhotoBanter.com.
The comments are property of their posters.