ONLY rotate and do nothing else

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xntest
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Joined: Mon Feb 26, 2007 11:07 pm

ONLY rotate and do nothing else

Post by xntest »

Hello,

I just want to rotate all JPEGs and their thumbs depending on EXIF-orientation flags (-jpegtrans exif) but I want to be very sure that nconvert do nothing else.

So I want that the picture quality remains even as the file dates, the EXIF-datas, and everything else.

Is that possible with nconvert and which command line must be used?


Thanks for help
bye
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xnview
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Re: ONLY rotate and do nothing else

Post by xnview »

xntest wrote:Hello,

I just want to rotate all JPEGs and their thumbs depending on EXIF-orientation flags (-jpegtrans exif) but I want to be very sure that nconvert do nothing else.

So I want that the picture quality remains even as the file dates, the EXIF-datas, and everything else.

Is that possible with nconvert and which command line must be used?
-jpegtrans exif don't change quality, exif, ... For file date, you must use -keepfiledate
And perhaps better to make that on a copy of your folder :-)
Pierre.
xntest
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Post by xntest »

Can I be very shure :) that "nconvert -jpegtrans exif -keepfiledate" do not change anything else than the rotation and the rotation of thumbs?
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xnview
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Post by xnview »

xntest wrote:Can I be very shure :) that "nconvert -jpegtrans exif -keepfiledate" do not change anything else than the rotation and the rotation of thumbs?
jpegtrans use lossless transformation, so the quality is not change. Some pixels can be cropped if the size is not a multiple of 4
Pierre.
bob.b

Not so easy

Post by bob.b »

xnview wrote:
xntest wrote:Can I be very shure :) that "nconvert -jpegtrans exif -keepfiledate" do not change anything else than the rotation and the rotation of thumbs?
jpegtrans use lossless transformation, so the quality is not change. Some pixels can be cropped if the size is not a multiple of 4
It's not so easy as it looks: using "nconvert -jpegtrans exif -keepfiledate" seems to change date/time information to actual. :-(
xntest
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Post by xntest »

Upps, that were not so good.
I didn't start konverting because I have to do it with 20.000 selfmade pictures, and I want to be sure that I do not lose any data.
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xnview
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Re: Not so easy

Post by xnview »

bob.b wrote:
xnview wrote:
xntest wrote:Can I be very shure :) that "nconvert -jpegtrans exif -keepfiledate" do not change anything else than the rotation and the rotation of thumbs?
jpegtrans use lossless transformation, so the quality is not change. Some pixels can be cropped if the size is not a multiple of 4
It's not so easy as it looks: using "nconvert -jpegtrans exif -keepfiledate" seems to change date/time information to actual. :-(
With nconvert on windows???
Pierre.
bob.b

Re: Not so easy

Post by bob.b »

xnview wrote:
bob.b wrote: It's not so easy as it looks: using "nconvert -jpegtrans exif -keepfiledate" seems to change date/time information to actual. :-(
With nconvert on windows???
Yes: "NCONVERT v4.78" on Windows.
(IMHO "-keepfiledate" parammeter "keeps" date/time of temporary "*.JP_" file produced while converting.)
BTW: What about some "-setexifdate" parammeter? It could be usefull...
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xnview
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Re: Not so easy

Post by xnview »

bob.b wrote:
xnview wrote:
bob.b wrote: It's not so easy as it looks: using "nconvert -jpegtrans exif -keepfiledate" seems to change date/time information to actual. :-(
With nconvert on windows???
Yes: "NCONVERT v4.78" on Windows.
(IMHO "-keepfiledate" parammeter "keeps" date/time of temporary "*.JP_" file produced while converting.)
BTW: What about some "-setexifdate" parammeter? It could be usefull...
Strange, i've tried nconvert -keepfiledate, and file system date are not changed.
Pierre.
bob.b

Re: Not so easy

Post by bob.b »

xnview wrote:Strange, i've tried nconvert -keepfiledate, and file system date are not changed.
:-( Tried on WinXP Pro, NCONVERT v4.78. Combination with "-jpegtrans *" works bad:
- parammeter "-keepfiledate" doesn't work (only in this combination, otherwise it works fine),
- parammeter "-o outfile.jpg" doesn't work, i.e. only transformation of "actual" file occurs.
Used three images taken from digital camera (unedited) and one downloaded (withouth EXIF). Typed:

Code: Select all

"C:\Program Files\XnView\nconvert.exe" -o C:\Temp\test.jpg -jpegtrans exif -keepfiledate IMG_7370.JPG
or

Code: Select all

"C:\Program Files\XnView\nconvert.exe" -jpegtrans exif -keepfiledate IMG_7370_JPG
.

(Damn! Your antispam kicked me off 7 times till I changed "three-x" string to something else... :-) )
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xnview
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Re: Not so easy

Post by xnview »

bob.b wrote:

Code: Select all

"C:\Program Files\XnView\nconvert.exe" -jpegtrans exif -keepfiledate IMG_7370_JPG
.
This command doesn't work??
Pierre.
bob.b

Re: Not so easy

Post by bob.b »

xnview wrote:
bob.b wrote:

Code: Select all

"C:\Program Files\XnView\nconvert.exe" -jpegtrans exif -keepfiledate IMG_7370_JPG
.
This command doesn't work??
Works fine but changes date. On both of my computers. (And I'm sorry about "IMG_7730_JPG" - right is "IMG_7730.JPG". Copied to clipboard "too short" part of line and edited later on notebook keyboard caused this error.)
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xnview
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Re: Not so easy

Post by xnview »

bob.b wrote:
xnview wrote:
bob.b wrote:

Code: Select all

"C:\Program Files\XnView\nconvert.exe" -jpegtrans exif -keepfiledate IMG_7370_JPG
.
This command doesn't work??
Works fine but changes date.
After my test, creation & modified date are not modified, so i don't understand
Pierre.
bob.b

Re: Not so easy

Post by bob.b »

xnview wrote:After my test, creation & modified date are not modified, so i don't understand
Something's wrong, something's strange... I'm using NCONVERT.EXE, v4.78, 590336 bytes, file created at 2007-03-14 08:54:56.
Here is example how it works (slightly shortened):

Code: Select all

C:\Temp>dir *.jpg
29.04.2007  17:15         3 115 191 IMG_7369.JPG
29.04.2007  17:15         3 791 149 IMG_7370.JPG
29.04.2007  17:15         2 436 978 IMG_7371.JPG

C:\Temp>"C:\Program Files\XnView\nconvert.exe"  -keepfiledate -jpegtrans exif *.jpg
** NCONVERT v4.78 (c) 1991-2005 Pierre-E Gougelet (Mar 14 2007/08:54:56) **
        Version for Windows NT/9x/2000  (All rights reserved)
** This is a freeware software (for non commercial use)

Lossless transformation of IMG_7369.JPG : OK
Lossless transformation of IMG_7370.JPG : OK
Lossless transformation of IMG_7371.JPG : OK

C:\Temp>dir *.jpg
11.05.2007  17:30         3 056 033 IMG_7369.JPG
11.05.2007  17:30         3 678 968 IMG_7370.JPG
11.05.2007  17:30         2 389 996 IMG_7371.JPG

C:\Temp>
Are there some dependencies on NConvert? May be it's something wrong on my system or whereother.
xntest
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Joined: Mon Feb 26, 2007 11:07 pm

Post by xntest »

Hi bob


My XP shows times of changing for a file in a CMD-Box.

I think if you check date with windows explorer you can see unchanged dates for saving or building for your jpeg files.

Sorry I don't know the exact translation and I use german Windows.
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