jhead は JPEGファイルのEXIF情報やサムネイル画像を操作するツール。
⇒ Exif Jpeg header manipulation tool
以下、Debian GNU/Linux etch でのマニュアルとヘルプのドキュメント。
$ jhead -h の結果
$ jhead -h
Jhead is a program for manipulating settings and thumnails in Exif jpeg headers
used by most Digital Cameras. v2.6 Matthias Wandel, April 29 2006.
http://www.sentex.net/~mwandel/jhead
Usage: jhead [options] files
Where:
files path/filenames with or without wildcards
[options] are:
GENERAL METADATA:
-te <name> Transfer exif header from another image file <name>
Uses same name mangling as '-st' option
-dc Delete comment field (as left by progs like Photoshop & Compupic)
-de Strip Exif section (smaller JPEG file, but lose digicam info)
-du Delete non image sections except for Exif and comment sections
-purejpg Strip all unnecessary data from jpeg (combines -dc -de and -du)
-ce Edit comment field. Uses environment variable 'editor' to
determine which editor to use. If editor not set, uses VI
under Unix and notepad with windows
-cs <name> Save comment section to a file
-ci <name> Insert comment section from a file. -cs and -ci use same naming
scheme as used by the -st option
-cl string Insert literal comment string
DATE / TIME MANIPULATION:
-ft Set file modification time to Exif time.
-n[format-string]
Rename files according to date. Uses exif date if present, file
date otherwise. If the optional format-string is not supplied,
the format is mmdd-hhmmss. If a format-string is given, it is
is passed to the 'strftime' function for formatting
In addition to strftime format codes:
'%f' as part of the string will include the original file name
'%i' will include a sequence number, starting from 1. You can
You can specify '%03i' for example to get leading zeros.
This feature is useful for ordering files from multiple digicams to
sequence of taking. Only renames files whose names are mostly
numerical (as assigned by digicam)
The '.jpg' is automatically added to the end of the name. If the
destination name already exists, a letter or digit is added to
the end of the name to make it unique.
-nf[format-string]
Same as -n, but rename regardless of original name
-a (Windows only) Rename files with same name but different extension
Use together with -n to rename .AVI files from exif in .THM files
for example
-ta<+|->h[:mm[:ss]]
Adjust time by h:mm backwards or forwards. Useful when having
taken pictures with the wrong time set on the camera, such as when
traveling across time zones or DST changes. Dates can be adjusted
by offsetting by 24 hours or more. For large date adjustments,
use the -da option
-da<date>-<date>
Adjust date by large amounts. This is used to fix photos from
cameras where the date got set back to the default camera date
by accident or battery removal.
To deal with different months and years having different numbers of
days, a simple date-month-year offset would result in unexpected
results. Instead, the difference is specified as desired date
minus original date. Date is specified as yyyy:mmm:dd or as date
and time in the format yyyy:mmm:dd/hh:mm:ss
-ts<time> Set the Exif internal time to <time>. <time> is in the format
yyyy:mm:dd-hh:mm:ss
THUMBNAIL MANIPULATION:
-dt Remove exif integral thumbnails. Typically trims 10k
-st <name> Save Exif thumbnail, if there is one, in file <name>
If output file name contains the substring "&i" then the
image file name is substitute for the &i. Note that quotes around
the argument are required for the '&' to be passed to the program.
An output name of '-' causes thumbnail to be written to stdout
-rt <name> Replace Exif thumbnail. Can only be done with headers that
already contain a thumbnail.
-rgt[size] Regnerate exif thumbnail. Only works if image already
contains a thumbail. size specifies maximum height or width of
thumbnail. Relies on 'mogrify' programs to be on path
ROTATION TAG MANIPULATION:
-autorot Invoke jpegtran to rotate images according to Exif orientation tag
Note: Windows users must get jpegtran for this to work
-norot Zero out the rotation tag. This to avoid some browsers from
rotating the image again after you rotated it but neglected to
clear the rotation tag
OUTPUT VERBOSITY CONTROL:
-h help (this text)
-v even more verbose output
-V Show jhead version
-exifmap Dump header bytes, annotate. Pipe thru sort for better viewing
-se Supress error messages relating to corrupt exif header structure
-c concise output
-nofinfo Don't show file info (name/size/date)
FILE MATCHING AND SELECTION:
-model model
Only process files from digicam containing model substring in
camera model description
-exonly Skip all files that don't have an exif header (skip all jpegs that
were not created by digicam)
-cmd command
Apply 'command' to every file, then re-insert exif and command
sections into the image. &i will be substituted for the input file
name, and &o (if &o is used). Use quotes around the command string
This is most useful in conjunction with the free ImageMagick tool.
For example, with my Canon S100, which suboptimally compresses
jpegs I can specify
jhead -cmd "mogrify -quality 80 &i" *.jpg
to re-compress a lot of images using ImageMagick to half the size,
and no visible loss of quality while keeping the exif header
Another invocation I like to use is jpegtran (hard to find for
windows). I type:
jhead -cmd "jpegtran -progressive &i &o" *.jpg
to convert jpegs to progressive jpegs (Unix jpegtran syntax
differs slightly)
-orp Only operate on 'portrait' aspect ratio images
-orl Only operate on 'landscape' aspect ratio images
$ man jhead の結果
JHEAD(1) JHEAD(1)
NAME
jhead - Digicam JPEG Exif header manipulation tool
SYNOPSIS
jhead [ options ] [ file... ]
DESCRIPTION
jhead is used to display and manipulate data contained in the Exif
header of JPEG images from digital cameras. By default, jhead displays
the more useful camera settings from the file in a user-friendly for-
mat.
jhead can also be used to manipulate some aspects of the image relating
to JPEG and Exif headers, such as changing the internal timestamps,
removing the thumbnail, or transferring Exif headers back into edited
images after graphical editors deleted the Exif header. jhead can also
be used to launch other programs, similar in style to the UNIX find
command, but much simpler.
OPTIONS
-autorot
Using the 'Orientation' tag of the Exif header, rotate the image
so that it is upright. The program jpegtran is used to perform
the rotation. This program is present in most Linux distribu-
tions. For windows, you need to get a copy of it. After rota-
tion, the orientation tag of the Exif header is set to '1' (nor-
mal orientation). The thumbnail is also rotated. Other fields
of the Exif header, including dimensions are untouched, but the
JPEG height/width are adjusted. This feature is especially use-
ful with newer Canon cameras, that set the orientation tag auto-
matically using a gravity sensor.
-norot Clears the rotation field in the Exif header without altering
the image. Useful if the images were previously rotated without
clearing the Exif rotation tag, as some image browsers will auto
rotate images when the rotation tag is set.
-dt Delete thumbnails from the Exif header, but leave the interest-
ing parts intact. This option truncates the thumbnail from the
Exif header, provided that the thumbnail is the last part of the
Exif header (which so far as I know is always the case). Exif
headers have a built-in thumbnail, which typically occupies
around 10k of space. This thumbnail is used by digital cameras.
Windows XP may also use this thumbnail if present (but it
doesn't need it). The thumbnails are too small to use even full
screen on the digicam's LCD. I have not encountered any adverse
side effects of deleting the thumbnails, even from the software
provided with my old Olympus digicam. Use with caution.
-rt file
Replace thumbnails from the Exif header with the content of file
file. This only works if the exif header already contains a
thumbnail, and the thumbnail is at the end of the header (both
always the case if the photo came from a digital camera)
-rgt Regenerate exif thumbnail. Relies on 'mogrify' program (from
ImageMagick) to regenerate the thumbnail. This only works if
the image already contains a thumbnail.
-de Delete the Exif header entirely. This leaves comments in the
comment section intact.
-dc Delete comment field from the JPEG header. Note that the com-
ment is not part of the Exif header.
-du Delete sections of jpeg that are not Exif, not comment, and oth-
erwise not contributing to the image either - such as data that
photoshop might leave in the image.
-purejpg
Delete all JPEG sections that aren't necessary for rendering the
image. Strips any metadata that various applications may have
left in the image. A combintion of the -de -dc and -du options.
-ce Edit the JPEG header comment field (note, this comment field is
outside the Exif structure and can be part of Exif and non Exif
style JPEG images).
A temporary file containing the comment is created and a text
editor is launched to edit the file. The editor is specified in
the EDITOR environment variable. if none is specified notpead
or vi are used under Windows and Unix respectively. After the
editor exits, the data is transferred back into the image, and
the temporary file deleted.
-cs file
Save comment section to a file
-ci file
Replace comment with text from file
-cl string
Replace comment with specified string from command line file
-st file
Save the integral thumbnail to file The thumbnail lives inside
the Exif header, and is a very low-res JPEG image. Note that
making any changes to a photo, except for with some programs,
generally wipes out the Exif header and with it the thumbnail.
The thumbnail is too low res to really use for anything.
This feature has an interesting 'relative path' option for spec-
ifying the thumbnail name. Whenever the name for file contains
the characters '&i', jhead will substitute the original file-
name for this name. This allows creating a 'relative name' when
doing a whole batch of files. For example, the incantation:
jhead -st thumbnails/&i *.jpg
would create a thumbnail for each .jpg file in the thumbnails
directory by the same name, (provided that the thumbnails direc-
tory exists, of course). Both Win32 and UNIX shells treat the
'&'character in a special way, so you have to put quotes around
that command line option for the '&' to even be passed to the
program.
If a '-' is specified for the output file, the thumbnail is sent
to stdout. (UNIX build only)
-te file
Transplant Exif header from a JPEG (with Exif header) in file
into the image that is manipulated. This option is useful if
you like to edit the photos but still want the Exif header on
your photos. As most photo editing programs will wipe out the
Exif header, this option can be used to re-copy them back from
original copies after editing the photos.
Like the '-st' option, this option uses a 'relative path', which
is useful for doing a batch of photos at a time. For example,
if you have a directory full of digital camera photos, before
editing them, you could copy them into the subdirectory 'origi-
nals. Then edit them. After editing, you can put the original
Exif headers back in to the whole directory of images at a time
using the incantation: jhead -te originals/&i *.jpg
-h Displays summary of command line options.
-v Makes the program even more verbose than it already is. Like
DOS programs, and unlike UNIX programs, Jhead gives feedback as
to what it is doing, even when nothing goes wrong. Windows user
that I am, when something doesn't give me feedback for 20 sec-
onds, I assume its crashed.
-se Suppress error messages relating to corrupt Exif header struc-
ture.
-V Print version info and compilation date.
-c Concise output. This causes picture info to be summarized on
one line instead of several. Useful for grep-ing through
images, as well as importing into spread sheets (data is space
delimited with quotes as text qualifier).
-model Restricts processing of files to those whose camera model, as
indicated by the Exif image information, contains the substring
specified in the argument after '-model'. For example, the fol-
lowing command will list only images that are from an S100 cam-
era:
jhead -model S100 *.jpg
jhead -model S100 *.jpg
I use this option to restrict my JPEG rectification to those
images that came from my Canon S100 digicam, (see the -cmd
option).
-exonly
Skip all files that don't have an Exif header. This skips all
files that did not come directly from the digital camera, as
most photo editing software does not preserve the Exif header
when saving pictures.
-n[format_string]
This option causes files to be renamed using the date informa-
tion from the Exif header "DateTimeOriginal" field. If the file
is not an Exif file, or the DateTimeOriginal does not contain a
valid value, the file date is used. Renaming is by default
restricted to files whose names consist largely of digits. This
effectively restricts renaming to files that have not already
been manually renamed, as the default sequential names from dig-
ital cameras consist largely of digits. Use the -nf option to
force renaming of all files.
If the format_string is omitted, the file will be renamed to
MMDD-HHMMSS. Note that this scheme doesn't include the year (I
never have photos from different years together anyway).
If a format_string is provided, it will be passed to the strf-
time function as the format string. In addition, if the format
string contains '%f', this will substitute the original name of
the file (minus extension). '%i' will substitute a sequence
number. Leading zeros can be specified like with printf - i.e.
'%04i' pads the number to 4 digits using leading zeros.
If the target name already exists, the name will be appended
with "a", "b", "c", etc, unless the name ends with a letter, in
which case it will be appended with "0", "1", "2", etc.
This feature is especially useful if more than one digital cam-
era was used to take pictures of an event. By renaming them to
a scheme according to date, they will automatically appear in
order of taking in most directory listings and image browsers.
Alternatively, if your image browser supports listing by file
time, you can use the -ft option to set the file time to the
time the photo was taken.
Some of the more useful arguments for strftime are:
%H Hour in 24-hour format (00 - 23)
%j Day of year as decimal number (001 - 366)
%m Month as decimal number (01 - 12)
%M Minute as decimal number (00 - 59)
%S Second as decimal number (00 - 59)
%w Weekday as decimal number (0 - 6; Sunday is 0)
%y Year without century, as decimal number (00 - 99)
%Y Year with century, as decimal number
Example:
jhead -n%Y%m%d-%H%M%S *.jpg This will rename files matched by
*.jpg in the format YYYYMMDD-HHMMSS
For a full listing of strftime arguments, look up the strftime
in them man pages. Note that some arguments to the strftime
function (not listed here) produce strings with characters such
as '/' and ':' that may not be valid as part of a filename on
various systems.
-nf Same as '-n' but renames files regardless of original file name.
-ta<+|->[timediff]
Adjust time stored in the Exif header by h:mm backwards or for-
wards. Useful when having taken pictures with the wrong time
set on the camera, such as after travelling across time zones,
or when daylight savings time has changed.
This option changes all Date/time fileds in the exif header,
including "DateTimeOriginal" (tag 0x9003) and "DateTimeDigi-
tized" (tag 0x9004).
-da<newdate>-<olddate>
Works like -ta, but for specifying large date offsets, to be
used when fixing dates from cameras where the date was set
incorrectly, such as having date and time reset by battery
removal on some cameras
Because different months and years have different numbers of
days in them, a simple offset for months, days, years would lead
to unexpected results at times. The time offset is thus speci-
fied as a difference between two dates, so that jhead can figure
out exactly how many days the timestamp needs to be adjusted by,
including leap years and daylight savings time changes. The
dates are specified as yyyy:mm:dd. For sub-day adjustments, a
time of day can also be included, by specifying yyyy:nn:dd+hh:mm
or yyyy:mm:dd+hh:mm:ss
Examples:
Year on camera was set to 2005 instead of 2004 for pictures
taken in April
jhead -da2005:03:01-2004:03:01
Default camera date is 2002:01:01, and date was reset on
2005:05:29 at 11:21 am
jhead -da2005:05:29+11:21-2002:01:01
-ts Sets the time stored in the Exif header to what is specified on
the command line. This option only changes the "DateTimeOrigi-
nal" (tar 0x9003) field, but leaves the "DateTimeDigitized" (tag
0x9004) field alone. Time must be specified as: yyyy:mm:dd-
hh:mm:ss
-ft Sets the file's system time stamp to what is stored in the Exif
header.
-cmd Executes the specified command on each Jepg file to be pro-
cessed.
The Exif section of each file is read before running the com-
mand, and reinserted after the command finishes.
The specified command invoked separately for each JPEG that is
processed, even if multiple files are specified (explicitly or
by wild card). I use this option to process whole directory
trees of JPEGs from my digital camera with jpegtran (Independent
JPEG group) and ImageMagick's 'MOGRIFY' command without loosing
the camera settings and other info stored in the Exif headers.
jpegtran is useful for lossless rotation, as well as for con-
verting JPEGs to progressive JPEGs (also a lossless process, but
results in typically 5% smaller files) I use mogrify for re-com-
pressing the images I get from my Canon PowerShot S100 to 80%
quality. The Canon JPEGs are either way too 'high quality' for
the resolution, or are suboptimally encoded. Using mogrify to
80% produces no detectable loss in quality, with files about
half the size.
Example use:
Having a whole directory tree of photos from my S100, I run the
following commands:
jhead -cmd "mogrify -quality 80 &i" -model S100 *.jpg
jhead -cmd "jpegtran -progressive &i > &o" *.jpg
The first command mogrifies all JPEGs in the tree that indicate
that they are from a Canon S100 in their Exif header to 80%
quality at the same resolution. This is a 'lossy' process, so I
only run it on files that are from the Canon, and only run it
once. The next command then takes a JPEGs and converts them to
progressive JPEGs. The result is the same images, with no dis-
cernible differences, stored in half the space. This only pro-
duces substantial savings on some cameras, such as the Canon
S100. The newer S110 and S300 cameras are smarter about how
they compress JPEG images, so re-mogrifying them may not give
you any savings unless you crank the quality way down. However,
turning them into progressive JPEG images is a lossless process
that typically makes image files 5% smaller.
Keeping the Exif header information is important to me, as I
like to check things like the shutter speed for some of my pho-
tos, and my HTML index generating program uses the Exif tags to
display the JPEG images in order of taking.
SEE ALSO
jpegtran(1), mogrify(1), rdjpgcom(1), wrjpgcom(1)
AUTHOR
Matthias Wandel
BUGS
After jhead runs a program to rotate or resize an image, the image
dimensions and thumbnail in the Exif header are not adjusted.
Modifying of Exif header data is very limited, as Jhead internally only
has a read only implementation of the file system contained in the Exif
header. For example, there is no way to replace the thumbnail or edit
the Exif comment in the Exif header. There is also no way to create
minimal exif headers.
Some CANON digital SLR cameras fail to adjust the effective sensor res-
olution when shooting at less than full resolution, causing jhead to
incorrectly miscalculate the sensor width and 35mm equivalent focal
length. Jhead usually gets blamed for this bug, but it is in fact a
camera bug, and jhead can't do much about it, and I'm not about to add
camera bug specific hacks to it.
Send bug reports to mwandel at sentex dot net.
COPYING PERMISSIONS
Jhead is 'public domain'. You may freely copy jhead, and reuse part or
all of its code in free or proprietary programs. I do however request
that you do not post my e-mail address in ways that spam robots can
harvest it.
jhead 2.6 29 April 2006 JHEAD(1)
tags: zlashdot Zura Exif Jpeg Linux Tool
Posted by NI-Lab. (@nilab)