JPEG EXIF replacement on windows at home

On 2017-05-04 10:16:29 +0000, android said:

In article ,
Roger Mills wrote:

On 03/05/2017 23:30, Roy Tremblay wrote:
On Wed, 03 May 2017 21:48:28 +0100,
Roger Mills actually wrote:

Have a look at jhead.exe

thanks.

I installed jhead.exe from http://www.sentex.net/~mwandel/jhead/
usage: https://www.w3.org/2000/10/swap/pim/jhead/usage

Looks like a linux transplant so it will take some getting used to.

Maybe. I'm not a Linux user, but I've so far managed to make it do what
I wanted to do without too much difficultly.

Not really sure what this thing can do for you that ExifTool can't...

Agreed.

ExifTool can manipulate most image file formats BTW, like PNG, TIFF and
most RAWs in addition to JPEG... And there is a GUI available for
Windows. Links to it is posted elsewhere in this thread.


--
Regards,

Savageduck

On 5/4/17 PDT 6:23 AM, Roy Tremblay wrote:

If the photo casually appears to be unedited and if it casually appears to
be taken with a certain camera at a certain date at a certain location &
time then I can use IPTC but I think EXIF is the metta data most people
casually expect out of a camera.

Crikey.

Rather than falsifying the photo, why not stip all EXIF data? Then lie
in the text if you must.

--

Coach: "Are you just ignorant, or merely apathetic?"
Player: "Coach, I don't know, and I don't care."

"Roy Tremblay" wrote

Here's one of the clearest explanations of EXIF
that I'm aware of. It provides some idea of how
the header format works:

https://www.media.mit.edu/pia/Resear...view/exif.html

| The modified metta data is intended to casually indicate that the edited
| photo should appear as if it was not edited except for size and as if it
| was taken out of a certain camera at a certain location at a certain date
&
| time.
|

I think I'm missing part of the story. It sounds like
you need EXIF data in order to upload photos. I've
never used a photo upload/hosting service, so I
don't understand why that's relevant.

| What would be nice is you output EXIF to csv.
| You edit the csv.
| Then you import that edited csv into a JPEG.
|

Yes. But again, someone has to design all that
and hardly anyone actually wants that functionality.
I once wrote my own utility to add IPTC data, but
I found that I just didn't use it. I keep photos
organized in folders, and I still recognize most of my
relatives, so I don't need a note telling me who's
in the photo.

| The only thing left would be the binary things like the thumbnail and
| calculated things like the x:y dimensions which can be a push button
| calculation inside a GUI.
|
| Is anything else binary in EXIF metta data but the thumbnail?
|
I guess that depends on what you mean by binary.
See the link above. Typical file header data design will
include various fields, with byte length markers and field
size markers, so that code can navigate the header.
The thumbnail, if it's there, can be one of 3 formats.
All are "binary". There's also a data location that tells you
which format is being used. So it's not just a binary data
blob that you need to be concerned with.

If you look at the link above you'll
see that some values are strings, while others are
numeric of various kinds. Of the strings, most are
single-byte ANSI format, but Microsoft cooked up their
own tags that are unicode.

If by non-binary you mean readable text, then only
the ANSI strings are non-binary. But then each of those
tags has a length marker. So you can't just change
"Canon" to "Panasonic" willy nilly. Length markers will
need to be changed and that change may affect pointers
elsewhere in the header. (A pointer being a value or tag
that holds the numeric offset into the file of another
value.) Otherwise parsing software will expect a 5-character
camera name (Canon) and will then end up trying to parse
the next tag from the bytes "onic". From there the whole
thing is likely to fail.

One of the Exif tags is actually a pointer to a whole other
group known as SubExif tags. If that pointer is not accurate
all SubExif tags will be unfindable.

That's why I said it's easier to change dates, because they're
fixed-length strings. But even that's tricky. JPG headers are
a mess, created by too many
cooks in the kitchen, with little that's really official. If you
look at a JPG in a hex editor you may see dates, but you
may see them in 2 or 3 places. See IView: DateTime.
DateTime Original. DateTime Digitized. They're stored in
different places. So just to change the date you need to
know all that, then edit the bytes for each date. But it's
only that easy because you're not changing the string length
of the data fields in the case of dates, so you can leave the
header structure undisturbed. And it's only that easy if you
don't also have date strings in something like an IPTC section
elsewhere in the header.

So, long story short, to do what you want someone
has to parse all header data and then completely rebuild
a new header, calculating internal pointers and tag length
markers accordingly. You can't just string the values together
and pack them back into the file. It's a complex,
interconnected structure.

| I was cropping with Irfanview and saving without EXIF.
|
| If I save to BMP or TIF or GIF that accomplishes the same task so that is
| ok with me since the quality of the cropped picture is not a big issue for
| uploads to the web.

I was talking about saving to non-JPG to prevent
damage. If you only crop and drop out EXIF,
then upload, there's no need to convert to a non
-lossy format. If you then add back Exif data that
should be feasible to do in a non-lossy manner, as
it has no direct connection to the image itself.

| I don't know the difference between the use on web sites of IPTC metta
data
| versis EXIF metta data. I see the buttons for IPTC in Irfanview and in
| Exiftool and Geosetter but I currently leave them empty.
|
| If IPTC is the way to set time date and location then I am good with that
I
| think if that is realistically what a camera would be settings.
|

I think IPTC was created by journalists. They use
it to add copyright, description, etc to photos for
publication. So it's a good format for adding info about
the subject of the photo. But I have no idea why or for
what purpose you need tags on your uploaded photos.
IPTC is also not as widely supported as EXIF.

| If the photo casually appears to be unedited and if it casually appears to
| be taken with a certain camera at a certain date at a certain location &
| time then I can use IPTC but I think EXIF is the metta data most people
| casually expect out of a camera.

Yes, probably. Though I have very few photos with
any data. I always convert them to non-lossy to work
on them, anyway. I regard all the header tags as little
more than debris. So that gets back to why you need
any tags in the first place. I doubt that most
people look at them or even know about them.

On Thu, 4 May 2017 07:07:45 -0700,
John McWilliams actually wrote:

Rather than falsifying the photo, why not stip all EXIF data? Then lie
in the text if you must.

Stripping the EXIF is too crudely obvious.

The upload had to be plausable.

The EXIF metta data "accidentally" left inside the picture makes it
casually plausable that the metta data indicated the camera the location,
the time and the date. The elevation was critical in this situation.

That the thumbnail and x:y dimensions and focal length match the cropped
image is all part of the casual plausability of the upload.

The proggies suggested by you experts provided 2/3 of the solution which is
good enough for now.

I don't think there is any more to learn about solutions unless you know of
a Windows solution which allows edits of all the EXIF metta data?

Thanks.

On Thu, 04 May 2017 09:32:09 -0400,
Paul actually wrote:

What purpose does forging incorrect GPS serve ?

Plausability.

You don't have the need.

I did.

But I'm not asking here if the need is valid.

I'm just asking if the software exists.

Otherwise I would ask some other group than windows and photos.

The suggested software proggies worked.

For 2/3 of the job anyways.

And that was enough to get the job done.

Thanks.

On 2017-05-04 13:23:08 +0000, Roy Tremblay said:

On Thu, 4 May 2017 08:40:33 -0400,
Mayayana actually wrote:

I wonder if you'll find anything better.

You must be correct because this is the right ng to ask.

There is familiarity to the character of your posts, and I have a
strong suspicion that given your various demands, that you live
somewhere in the Santa Cruz mountains above San Jose. With that
suspicion I don't have much hope for this thread ending tidily.



--
Regards,

Savageduck

On 2017-05-04 12:07:16 +0000, Roy Tremblay said:

On Wed, 3 May 2017 18:22:27 -0700,
Savageduck actually wrote:

Your basic, all access EXIF editing tool is Exiftool.

Jhead and exiftool.exe were very complex so I stopped testing for now as I
am on Windows so a user interface is expected.

All I want is for all the EXIF fields to show up on some sort of form where
there is a value for each that can be changed.

Exifer is easy to insert exif from another file and easy to fix thumbnails
after cropping but Exifer only seems to easily edit simple things like the
date but not the camera or GPS data.

Geosetter crashes a lot but seems to be the only suggested program with a
GUI that allows GPS location to be set.

Lightroom

None of the suggested GUI based programs seem to allow editing of the
camera, firmware, and other information yet.

As a matter of curiosity, what EXIF fields do you wish to edit, and to
what purpose?

Thumbnail, date, time, location, altitude, camera, firmware version,

Hmmm...
Why camera, and firmware version?

For example, if you post a picture on the web that you cropped, if you're
not familiar with the GPS or thumbnail problem, you end up posting not only
the exact location but also the entire picture even though you thought you
cropped it.

First, if you end up posting what amounts to the entire image, as if
uncropped, then there is an issue with either your methodology, or your
editing software. Stripping location data should be the simplest of
"save as" options.

Then what photo editing software are you using?

None. Irfanview. For cropping only.
Irfanview wipes out EXIF easily but doesn't allow judicious changes.

I think I see your problem.
Most good photo editing software has the ability to make sensible EXIF
edits, including an option to remove location information only.

...and have you considered the possible existence of any of several
invisible digital watermarks such as those from Digimarc, or Signum
SureSign?

Pictures are mine so watermarks shouldn't be there unless the camera puts
them there which could be the case (how would I know?).

If they are yours, and you don't subscribe to Digimarc (which I doubt),
they are not going to be watermarked.


--
Regards,

Savageduck

In article , Mayayana
wrote:


| Exifer is easy to insert exif from another file and easy to fix thumbnails
| after cropping but Exifer only seems to easily edit simple things like the
| date but not the camera or GPS data.
|
I wonder if you'll find anything better. What you
want is something that will display all header fields,
let you edit any, then rebuild the header and reinsert
it. That's not a terribly complex task, but there are
two problems:

1) Since there's no reason for anyone to want to
replace something like camera model or shutter speed
data, there's no reason to provide such a function.

the main reason to change the camera model or exposure info is to
fraudulently enter photo contests.

there are even threads on dpreview where someone states they want to
enter a photo contest but their camera does not qualify for one reason
or another, so they (foolishly) brag that they modified the exif and
then submitted it.

2) Rebuilding the header is a lot more work than editing.
It's easy to replace dates because the number of bytes
doesn't change, so it doesn't require rebuilding the entire
file header. It only requires editing specific bytes.

exif editing utilities do all that *for* you.

So you're looking for something that no one needs
and which is a pain in the neck to carry out.

exif editing utilities exist and it's actually very easy to do.

| For example, if you post a picture on the web that you cropped, if you're
| not familiar with the GPS or thumbnail problem, you end up posting not
only
| the exact location but also the entire picture even though you thought you
| cropped it.
|

If it were me I'd strip all data, saving the image
first to BMP or TIF. (You should never work on
JPGs, anyway. Every edit loses image data.)

editing exif on a jpg does not affect the image data at all.

Then
if you want to add tags use IPTC. EXIF is mainly
intended for technical image data. IPTC is designed
to store general information, like location,
date, description, etc. Since IPTC is used by
journalists, and the structure is simple, I wouldn't
be surprised if there's some kind of simple program
available for adding the comments.

they each have their use.

On 5/4/17 12:07 AM, nospam wrote:
In article , dale
wrote:


I'd like an app that removes EXIF from jpeg files

exiftool can do that (and more):
http://www.sno.phy.queensu.ca/~phil/exiftool/


thanks

--
dale | http://www.dalekelly.org

On 5/4/17 9:06 AM, Paul wrote:
dale wrote:
On 5/3/17 8:25 PM, Paul wrote:
an expert
can detect as being "fake".

I'd like an app that removes EXIF from jpeg files

I'm trying to use open graph protocol and they mentioned, somewhere
... , that EXIF might be a problem

http://ogp.me/

and besides one time,, in a reply not a post, in which I can't quite
remember what I did I can't get a jpeg to show up on a post in facebook

for instance, from the link

meta property="og:image" content="http://example.com/ogp.jpg" /
meta property="og:image:secure_url"
content="https://secure.example.com/ogp.jpg" /
meta property="og:image:type" content="image/jpeg" /
meta property="og:image:width" content="400" /
meta property="og:image:height" content="300" /

the debugger

https://developers.facebook.com/tools/debug/sharing

tells me my image is either too small or too big, but the same image
is "inferred" from my blog

searching tells me there might be problems with my connection, yet my
blog is a subdirectory off my main directory where the index.html file
I am working with is in



Get yourself a hex editor.

On Windows, you can try HxD for example.

The purpose of getting such a tool, is for "visibility", so
you can see how the image formats work.

https://mh-nexus.de/en/hxd/

*******

On disk here, I have rdjpgcom.c. This would be part of the
independent JPEG library.

Instead of 4CC codes, it uses 0xFF and then the Marker value.

In a sample file here, I see FFD8 FFE0, the D8 is Start Of Image,
the E0 is Application Specific Marker.

/*
* JPEG markers consist of one or more 0xFF bytes, followed by a marker
* code byte (which is not an FF). Here are the marker codes of interest
* in this program. (See jdmarker.c for a more complete list.)
*/

#define M_SOF0 0xC0 /* Start Of Frame N */
#define M_SOF1 0xC1 /* N indicates which compression process */
#define M_SOF2 0xC2 /* Only SOF0-SOF2 are now in common use */
#define M_SOF3 0xC3
#define M_SOF5 0xC5 /* NB: codes C4 and CC are NOT SOF markers */
#define M_SOF6 0xC6
#define M_SOF7 0xC7
#define M_SOF9 0xC9
#define M_SOF10 0xCA
#define M_SOF11 0xCB
#define M_SOF13 0xCD
#define M_SOF14 0xCE
#define M_SOF15 0xCF
#define M_SOI 0xD8 /* Start Of Image (beginning of datastream) */
#define M_EOI 0xD9 /* End Of Image (end of datastream) */
#define M_SOS 0xDA /* Start Of Scan (begins compressed data) */
#define M_APP0 0xE0 /* Application-specific marker, type N */
#define M_APP12 0xEC /* (we don't bother to list all 16
APPn's) */
#define M_COM 0xFE /* COMment */

*******

FFD8
FFE0 "JFIF"
FFE1 "Exif"

So it almost looks like JPG packetizes data, and other
informations are stuffed in, willy nilly, with an extension
mechanism (APPn).

In particular, XMP (not in my sample), can now extend past
a max length 64K JPG segment, as a result of messing about
by outfits like Google. They decided to add another image
to the image, a "depth map". Just as examples of how a
venerable format can be made unreadable by modern
software engineers.

I'd hoped, when I saw rdjpgcom.c in my disk search, that
it was going to be able to dump the segments and lengths,
but it doesn't even do that much.

Suffice to say, the Exif is not the only supplier of size
information. JPG existed before Exif or XMP, and survived quite
nicely without it.

So if you wanted a comprehensive tool that could make
sense of any JPG file (without having to read code or
format specifications), forget it.

*******

As for your notion of "too big", there's no such thing.
Images can be resampled to make them fit in a presentation.
Exactly sized bitmaps don't have to be used for everything.
The video card has a very nice hardware scaler, which is
lightning fast. I can't imagine a software standard
in 2017, that doesn't have some sort of resize-on-the-fly
for such a situation. Maybe your "presentation" size is
bigger than the frame defined to hold it ? If so, it
should still present itself, even if portions are cropped.
We've been able to do that for, oh, 30 years or so
(PostScript imaging model).

So what you need to do, is research where these messages
are coming from, and what they might actually mean. The
error messages might not be based on fact, for example.

It's like the bloody OCR I've used in the past, that
says "the image must be between 200DPI and 400DPI",
and I keep seeing that message over and over again.
And I have to bodge the source, to suit the idiots.
It takes me half the day to get the source to fit
within the limit. You mean they couldn't take a
crack at bodging it themselves ? Grrr.

*******

Utility writing, is one of the lowest forms of
software development. The "smart people" write the
kernel or the compilers. That leaves the "bumpkins"
for writing utilities. That's how my software organization
at work was arranged. I developed this model, after
needing to do some data recovery, and the utility writer
had made a useless application for the purpose. I
had to fix it, before I could do emergency data
recovery. I've had a low opinion of utility writers
every since. There's nothing like fixing a program
at source, when you're under time pressure, and
you're not a CS grad. First you fix the program,
then you get to do data recovery.

I got that same feeling when downloading XMP-Toolkit-SDK-CC201412.zip.
The library parts built fine, in no time at all.
But DumpFile was not properly anchored in CMake,
and it took me a week to hand-hack a make file
for it myself (because this was my first CMake
and I don't know how to fix stuff like that).
Then, when it was finished (yes, it compiled and
linked properly), the output was "pure crap". Now,
why do I have such a low opinion of software, and
the "developer hierarchy" where the bumpkin writes
the user-facing utility :-) A week of effort, wasted.

Paul

gonna have to check back on this, after say 25 years of knowing about
hex editors I never took it up, what I would prefer is an editor that
displays native stuff in a native order then leaves the interpretation
to open/save development

anyways, thanks

--
dale | http://www.dalekelly.org