Rotate JPEG Pictures and JPEG Quality

Rotate JPEG Pictures and JPEG Quality

Post by Hon-Chi N » Mon, 19 Jun 2000 04:00:00



Hi

Is there any graphic program that can rotate JPEG pictures 90 degree
clockwise or counter-clockwise WITHOUT changing the picture quality?  It
can run under either MS Win or Linux.

I have some JPEG photos taken vertically (width < height) using my
digicam.  However, my digicam stores all photos horizontally, which
makes viewing unnatural for the "vertical" photos -- I had to turn my
head sideway to view them.
[ Man, don't I wish my digicam can sense its orientation when the photos
are taken, and adjust them accordingly.  :^) ]

I tried using Photo Editor on MS Win and XV on Linux to rotate the
photos to the correct orientation.  However, I would like to keep the
original quality.  Strangely, I found that, using either of the 2
programs, if I saved the photos using 100% quality, the file sizes grew
about 38% larger, and if I saved using 95%, they shrunk about 33%
compared to the originals.

I don't know much about JPEG format, but I assume the file size is an
indication of its quality.

Here are my questions:

1. Is it possible to rotate a JPEG picture without changing its quality
   (file size)?

2. If so, is there a program that can rotate JPEG pictures 90 degree in
   either direction WITHOUT changing the picture quality?  And
   preferably the program can be executed on command-line to batch
   process multiple pictures.

Thanks.  I appreciate your help.

Regards
Hon-Chi

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Rotate JPEG Pictures and JPEG Quality

Post by John Smit » Mon, 19 Jun 2000 04:00:00


ACDSee can rotate jpeg.

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Roge » Tue, 20 Jun 2000 04:00:00


You damn them with faint praise!  :) ACDSee is great. Lightning fast,
rotates image without affecting image quality or file size.

> ACDSee can rotate jpeg.

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Andre » Tue, 20 Jun 2000 04:00:00


JPEG Wizard can do it in batch
 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Guido Vollbedin » Tue, 20 Jun 2000 04:00:00



> Here are my questions:

> 1. Is it possible to rotate a JPEG picture without changing its quality
>    (file size)?

Yes, lossless rotation, see http://sylvana.net/jpegcrop/ .

Quote:> 2. If so, is there a program that can rotate JPEG pictures 90 degree in
>    either direction WITHOUT changing the picture quality?

On Windows you can try Jpegcrop, it does lossless crop & rotation.

Quote:>    And
>    preferably the program can be executed on command-line to batch
>    process multiple pictures.

IJG jpegtran (v6b) can be used on Windows and Linux.

Regards,
Guido

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Guido Vollbedin » Tue, 20 Jun 2000 04:00:00


Below are my scripts for quick and save (replace original after success)
rotation under Linux.

Regards,
Guido

------------------------------------------------------------
# left
for i
do
 jpegtran -rot 270 -copy all -opt <$i >`dirname $i`/`basename $i .jpg`l.jpg
 if [ $? != 0 ]
 then
  echo Error while transforming $i - skipped.
 else
  rm $i
  mv `dirname $i`/`basename $i .jpg`l.jpg $i
 fi
done

------------------------------------------------------------
# right
for i
do
 jpegtran -rot 90 -copy all -opt <$i >`dirname $i`/`basename $i .jpg`r.jpg
 if [ $? != 0 ]
 then
  echo Error while transforming $i - skipped.
 else
  rm $i
  mv `dirname $i`/`basename $i .jpg`r.jpg $i
 fi
done

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Bryan Bigger » Tue, 20 Jun 2000 04:00:00


yeahbut,
   You have to rotate them permanently, changing the original, there is
no temporary rotate for viewing on the screen. (as far as I know, I'd
love to hear about it if there is). This is a problem for me when using
ACDsee to view images stored on CD. This is the main reason that I have
not bought the program.
Bryan

> You damn them with faint praise!  :) ACDSee is great. Lightning fast,
> rotates image without affecting image quality or file size.


> > ACDSee can rotate jpeg.

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by piamo » Tue, 20 Jun 2000 04:00:00


I just rotate in photoshop (and save to a new file if I'm going
to keep it on that form).  I haven't noticed any loss of
information or degredation in quality.  Am I missing something?

-Jeff

Got questions?  Get answers over the phone at Keen.com.
Up to 100 minutes free!
http://www.keen.com

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Roland Karlsso » Tue, 20 Jun 2000 04:00:00



Quote:> I just rotate in photoshop (and save to a new file if I'm going
> to keep it on that form).  I haven't noticed any loss of
> information or degredation in quality.  Am I missing something?

Yepp. You are missing that it is possible to rotate
JPEG without any loss at all. Although maybe not
absolutely neccessary, it is nice to know that you lost nothing.

As an extra bonus - the rotation will preserve the file size.
Rotating and saving in photoshop to keep the nearly same quality
will probably increase the file size.

I use ACDSee to rotate the images.
It preserves the EXIF info also,
which is very nice.

Roland

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Radiskul » Tue, 20 Jun 2000 04:00:00


I have used ACDSee for years.  I finally got a digital camera (CP990) and
bought several different editing programs -- what do I use now?  ACDSEE  !!
It is great.

It does not rotate (or do anything) permanently until you save the damn
thingj, every edit is on screen only.  Even then you can save it to a
different file name and keep the original (which is a good idea with all
pix).

Well worth the money.

cheers


> yeahbut,
>    You have to rotate them permanently, changing the original, there is
> no temporary rotate for viewing on the screen. (as far as I know, I'd
> love to hear about it if there is). This is a problem for me when using
> ACDsee to view images stored on CD. This is the main reason that I have
> not bought the program.
> Bryan


> > You damn them with faint praise!  :) ACDSee is great. Lightning fast,
> > rotates image without affecting image quality or file size.


> > > ACDSee can rotate jpeg.

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Bryan Bigger » Tue, 20 Jun 2000 04:00:00



> I have used ACDSee for years.  I finally got a digital camera (CP990) and
> bought several different editing programs -- what do I use now?  ACDSEE  !!
> It is great.

> It does not rotate (or do anything) permanently until you save the damn
> thingj, every edit is on screen only.  Even then you can save it to a
> different file name and keep the original (which is a good idea with all
> pix).

> Well worth the money.

> cheers

> B.

About 1/4 of my shots are rotated, and they are stored on CDs so I can't
change them permanently. Unless there is a quick way to spin them on the
screen, it is just too awkward to use ACDsee at this time for me. You
can use a plugin to rotate shots, but it is about a 5 keystroke
sequence. Bryan
 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Jack Berli » Tue, 20 Jun 2000 04:00:00


Jeff,
The damage is there, and if you are not seeing it, it is because your
jpegs were so mildly compressed that artifacts did not manifest visibly
yet (however undercompression to compensate is a high price to pay if
your target is the web).  Photoshop will have to uncompress the original
(IDCT, Y/UV->RGB color conversion), rotate, then recompress (RGB->Y/UV
color conversion, DCT).  Both of the color conversions and the DCT are
damaging to your image.
Hope this helps,
jack
--
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> I just rotate in photoshop (and save to a new file if I'm going
> to keep it on that form).  I haven't noticed any loss of
> information or degredation in quality.  Am I missing something?

> -Jeff

> Got questions?  Get answers over the phone at Keen.com.
> Up to 100 minutes free!
> http://www.veryComputer.com/

 
 
 

Rotate JPEG Pictures and JPEG Quality

Post by Roge » Wed, 21 Jun 2000 04:00:00


I use version 2.4 of ACDSee (I have a later version, but prefer 2.4) and when I
have a .jpg onscreen, I hit Ctrl+R, the little window pops up, I choose the
rotation I want, I'm done. Don't need to save it, it's done automatically.
There's no recompressing or loss of quality. The way I figure it I've pressed two
keys at the same time and then clicked one button. Not too bad. If in a hurry or
something is chasing me, I can do it in about a half second. Of course if your
pics are burned onto a CD it won't change them permanently, but neither will any
other program.
Quote:> About 1/4 of my shots are rotated, and they are stored on CDs so I can't
> change them permanently. Unless there is a quick way to spin them on the
> screen, it is just too awkward to use ACDsee at this time for me. You
> can use a plugin to rotate shots, but it is about a 5 keystroke
> sequence. Bryan

 
 
 

1. JPEG to Motion JPEG (M-JPEG) encoder?

Does anyone know of a JPEG to Motion JPEG (M-JPEG) encoder?
Preferrably a commercial solution is desired, but share/freeware
could be considered. It needs to be able to run on DEC Unix & Solaris.
Command line, or linkable code is perferred.
Thx,
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