What program is best at JPEG compression?

On Jul 23, 1:47 pm, "David" <some... RemoveThis @some-where.com> wrote:
> "imbsysop" <imbsy... RemoveThis @yahoo.com> wrote in message
>
> news:dul8a35t354eddpumghhjsddjkmrpqp1l0@4ax.com...> I've always thought jpeg and its compression algorithm
> > were subject to
> > a general standard and not to any program makers' fantasy
> > ..????

The standard has a large number of free parameters in it. And although
many applications use a scaled version of the original canonical
quantisation table given in the standard other encoders have made
different choices. And in some cases an encoder with all the time in
the world can find an optimised quantisation table for a specific
target image. This helps encode physically small dimensioned images in
a more compact JPEG file.
>
> As with MPEG, JPEG decoders are deterministic (given the
> same input, they all produce the same output), but the
> encoders are not. Choices can be made during encoding even
> for algorithms that produce the same output file size.

Sadly even though the specification of JPEG is fairly precise there is
still enough latitude for the decoder that there is plenty of scope
for different decoders producing different images from the same JPEG
encoded file. The most commonly noticeable implementation differences
are in the chroma subsampling treatment (seriously broken in PSPro 9's
encoder). And where for example the IJG codec uses interpolation
whereas Adobe uses pixel replication - both of these methods have
their merits and demerits.

There are other options dating from the bad old days when computing a
DCT was still hard work that permit various speed for accuracy trade-
offs (much less of an issue these days with fast hardware floating
point support).

Regards,
Martin Brown
 >> Stay informed about: What program is best at JPEG compression? 

On Thu, 19 Jul 2007 09:57:39 -0500, "CSM1" <nomail DeleteThis @nomoremail.com>
wrote:

><u235bomb DeleteThis @ml1.net> wrote in message
>news:1184835628.283392.315080@i38g2000prf.googlegroups.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 ..????
 >> Stay informed about: What program is best at JPEG compression? 

"imbsysop" <imbsysop.DeleteThis@yahoo.com> wrote in message
news:dul8a35t354eddpumghhjsddjkmrpqp1l0@4ax.com...
> I've always thought jpeg and its compression algorithm
> were subject to
> a general standard and not to any program makers' fantasy
> ..????
>
As with MPEG, JPEG decoders are deterministic (given the
same input, they all produce the same output), but the
encoders are not. Choices can be made during encoding even
for algorithms that produce the same output file size. MPEG
encoding has even more variance and there can be enormous
quality differences in the decoded output of a given average
bit rate. Coders for DVDs do a good job because the encoding
does not have to be done in real time and multipass encoding
and larger GOP sizes are used.

David
 >> Stay informed about: What program is best at JPEG compression? 

In rec.photo.digital Fed-Up-With-Corel <nobody.DeleteThis@noplace.org> 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.
 >> Stay informed about: What program is best at JPEG compression? 

"imbsysop" <imbsysop DeleteThis @yahoo.com> wrote in message
news:dul8a35t354eddpumghhjsddjkmrpqp1l0@4ax.com...
> On Thu, 19 Jul 2007 09:57:39 -0500, "CSM1" <nomail DeleteThis @nomoremail.com>
> wrote:
>
>><u235bomb DeleteThis @ml1.net> wrote in message
>>news:1184835628.283392.315080@i38g2000prf.googlegroups.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

If you are talking about Digital cameras, you use the EXIF 2.2 spec.
http://www.exif.org/Exif2-2.PDF

There is a lot of room for interpolation of the application of JPEG
compression.
Many factors that have to be balanced for the best result.

Since Jpeg is lossy, it throws away a lot of important information that is
gone forever, if you choose wrong.


--
CSM1
http://www.carlmcmillan.com
--
 >> Stay informed about: What program is best at JPEG compression? 

This message is not archived
 >> Stay informed about: What program is best at JPEG compression? 

u235bomb RemoveThis @ml1.net wrote:
> 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.

No; quantisation, and it effects on data size are well
defined, but the visual effects of various quantisations
(the lossy part) are not completely understood.

This is where companies apply their "magic"
http://www.jpegwizard.com/
http://vision.arc.nasa.gov/dctune/

This page looks helpful:
http://www.webreference.com/dev/graphics/

BugBear
 >> Stay informed about: What program is best at JPEG compression? 

This message is not archived
 >> Stay informed about: What program is best at JPEG compression? 

On Mon, 23 Jul 2007 14:40:31 GMT, "CSM1" <nomail DeleteThis @nomoremail.com>
wrote:

>"imbsysop" <imbsysop DeleteThis @yahoo.com> wrote in message
>news:dul8a35t354eddpumghhjsddjkmrpqp1l0@4ax.com...
>> On Thu, 19 Jul 2007 09:57:39 -0500, "CSM1" <nomail DeleteThis @nomoremail.com>
>> wrote:
>>
>>><u235bomb DeleteThis @ml1.net> wrote in message
>>>news:1184835628.283392.315080@i38g2000prf.googlegroups.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
 >> Stay informed about: 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.
 >> Stay informed about: 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
 >> Stay informed about: What program is best at JPEG compression? 

In article <46a4ec77 RemoveThis @news.meer.net>, Bill Tuthill <ccreekin RemoveThis @yahoo.com> wrote:
>In rec.photo.digital Fed-Up-With-Corel <nobody RemoveThis @noplace.org> 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.
 >> Stay informed about: 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
 >> Stay informed about: What program is best at JPEG compression?