Do you use lossless JPEG recompression tools?

On Jan 19, 8:55 pm, John Navas wrote:
On Sat, 19 Jan 2008 07:05:41 -0800 (PST), Sachin Garg
wrote in
:

On Jan 19, 12:57 pm, "David J Taylor" -
this-bit.nor-this-bit.co.uk wrote:
Sachin Garg wrote:

[]

Can I have any more opinions? Is anyone else here using these tools?

Not using - never seen any need.

OK.

btw, similar tools are possible for RAW files too, which are much
bigger than jpegs. Will such a lossless compression tool for raw
files, with 20-25% compression, be more useful?

RAW formats are proprietary to particular products, and thus unsuitable
for archival storage. Adobe DNG is a better alternative that has
compression built-in, probably not recompressible.

There are so many independent tools that support all these raw formats
that I don't think we need to worry too much about any particular
company stopping support for them.

About DNG, its a great format adobe has created but I don't use it
(yet) for two reasons. A) I can't convert my DNG's back to original
format, if needed (some tools don't support dng). B) If ever support
for my raw files disappears from planet, I can 'then' convert my
images to DNG, why do it now :-)

Sachin Garg [India]
www.sachingarg.com | www.c10n.info

On Sat, 19 Jan 2008 15:59:32 GMT, "David J Taylor"
wrote in
:

John Navas wrote:
[]
My own advice is to save important images in lossless PNG format,
which preserves image quality with lossless compression, is widely
accepted, and is likely to be supported for a very long time to come.
AFAIK, PNG images can't be recompressed significantly.

Agreed, with the proviso that if you are /starting/ with a JPEG image,
downloaded from the camera or flash-card for example, the only point in
converting it for saving as PNG would be if you consider PNG a more robust
saving format. Otherwise, conversion will simply loose the metadata from
the JPEG file.

Good point. TIFF can store EXIF metadata, but is much complex and
problematic.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

Sachin Garg wrote in news:dc2987e5-b758-45ef-b644-
:


There are a number of tools available which can do "lossless"
compression of jpeg files, they get around 20-25% compression. There
are both commercial/proprietary (StufIt) and free/open-source options
(PackJPG, PAQ etc...).

Have you tried any such tool? Do you use any?

I am in process of publishing an image compression benchmark and want
to know what is in actual popular use and what all is only
academically interesting.

And if not, then why not? what do you think is missing in them that
would make you change your mind?

Sachin Garg [India]
www.sachingarg.com | www.c10n.info

I don't use JPG format except when I am making an image for web/email
purposes. I prefer to keep the PSD files, with layers and edits, as my
originals. Usually distribute flattened 8-bit TIF files to clients.

On Sat, 19 Jan 2008 08:34:43 -0800 (PST), Sachin Garg
wrote in
:

On Jan 19, 8:55 pm, John Navas wrote:

RAW formats are proprietary to particular products, and thus unsuitable
for archival storage. Adobe DNG is a better alternative that has
compression built-in, probably not recompressible.

There are so many independent tools that support all these raw formats
that I don't think we need to worry too much about any particular
company stopping support for them.

About DNG, its a great format adobe has created but I don't use it
(yet) for two reasons. A) I can't convert my DNG's back to original
format, if needed (some tools don't support dng). B) If ever support
for my raw files disappears from planet, I can 'then' convert my
images to DNG, why do it now :-)

For ease of browsing, manipulation and management. I think it's pretty
clear that DNG is better than RAW as a general purpose file format.
I personally don't have any use for tools that don't support DNG.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)

John Navas wrote:


RAW formats are proprietary to particular products, and thus unsuitable
for archival storage.

That's not really true. I have a Canon 30D and use raw. The "DCRaw"
program decodes the files fine, and is available in
fairly readable plain C code, which will be compilable forever. Thus,
they are archival.

Also, they are fairly small since they are actually monochrome files.
Even losslessly compressed BMP files of their RGB decodings are
vastly larger.

Doug McDonald

On Jan 19, 10:00 pm, Ray Paseur
wrote:
Sachin Garg wrote in news:dc2987e5-b758-45ef-b644-
:





There are a number of tools available which can do "lossless"
compression of jpeg files, they get around 20-25% compression. There
are both commercial/proprietary (StufIt) and free/open-source options
(PackJPG, PAQ etc...).

Have you tried any such tool? Do you use any?

I am in process of publishing an image compression benchmark and want
to know what is in actual popular use and what all is only
academically interesting.

And if not, then why not? what do you think is missing in them that
would make you change your mind?

I don't use JPG format except when I am making an image for web/email
purposes. I prefer to keep the PSD files, with layers and edits, as my
originals. Usually distribute flattened 8-bit TIF files to clients.

Thanks for sharing this.

Sachin Garg [India]
www.sachingarg.com | www.c10n.info

On Sat, 19 Jan 2008 08:00:07 GMT
"David J Taylor"
wrote:

Sachin Garg wrote:
[]
This concern might be true for proprietary formats from unknown
companies, but is it really a concern when its an open-source
solution (or if its from a dependable company)?

Any proprietary format is dubious - look at the difficulties in
reading old word-processor formats. Open-source can be the
kiss-of-death for a project, as the programmers loose interest and
move onto something else. Seen that happen time after time.

Hmmm... I have to quibble here a little bit.

Proprietary formats are always dubious, primarily for the reason you
note: that the company can withdraw support for the format and leave
you high and dry.

An open format with an open source implementation *cannot* die unless
it is so wrong-headed that both the developers and the users abandon
it. If an open source project produces something useful, it *will*
survive even if the original developers leave the stage. I've seen
that happen time after time. GIMP and GeomView come to mind.

Open source and proprietary projects come and go. One difference
is that the products of proprietary development can die completely,
while the products of open source development always have the option
to live on.

Stick to standard JPEG.

On this I agree. Open source or not, I don't see a reason to add
further compression on top of JPEG. I could change my mind if
presented with a compelling reason, however.

Paul Allen

Paul Allen wrote:
[]
Hmmm... I have to quibble here a little bit.
[]
Paul Allen

That's fine, Paul, I /was/ being a little tongue-in-cheek! Open-source
isn't the be-all and end-all that some people believe, though.

Cheers,
David

On Sat, 19 Jan 2008 20:48:35 GMT
"David J Taylor"
wrote:

Paul Allen wrote:
[]
Hmmm... I have to quibble here a little bit.
[]
Paul Allen

That's fine, Paul, I /was/ being a little tongue-in-cheek!
Open-source isn't the be-all and end-all that some people believe,
though.

Ah! For the lack of a smiley, I needlessly unloaded on you. Sorry!

But you still seem to be listing a little bit to port on this.
I don't think I've ever met anyone who believed open source was the
be-all and end-all. Open source certainly has advantages, but
everyone agrees that PhotoShop is the standard against which things
like the GIMP are measured. I have had people say to my face that
I was a Communist for using open source. I think the extremists on
both ends are best ignored.

Paul Allen

Paul Allen wrote:
On Sat, 19 Jan 2008 20:48:35 GMT
"David J Taylor"
wrote:

Paul Allen wrote:
[]
Hmmm... I have to quibble here a little bit.
[]
Paul Allen

That's fine, Paul, I /was/ being a little tongue-in-cheek!
Open-source isn't the be-all and end-all that some people believe,
though.

Ah! For the lack of a smiley, I needlessly unloaded on you. Sorry!

But you still seem to be listing a little bit to port on this.
I don't think I've ever met anyone who believed open source was the
be-all and end-all. Open source certainly has advantages, but
everyone agrees that PhotoShop is the standard against which things
like the GIMP are measured. I have had people say to my face that
I was a Communist for using open source. I think the extremists on
both ends are best ignored.

In some cases the open-source product is the gold standard against the
commercial products are judged, although of course you'll never find a
seller who will admit that :-)

But in this case what matters is not the open-sourcing of software,
but simply publishing the format or interface spec, so that you're not
completely dependent on the longevity or whim of a particular
supplier.

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]