NConvert useage: option -n

[cday]

Could someone please provide an explanation for the operation of the following option listed in the help file:

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-n start end step : Begin End Step (for image sequence)

The option dates back to the early days of NConvert, but I am unable to find any explanation of its operation, intended useage or example of its use through searching the forum or a Google search...

Our forum librarian, who has uncanny search powers

Helmut who was any early NConvert user

[oops66]

Hello ... A sample with option -n is into the xnview wiki, did not help?
http://www.xnview.com/wiki/index.php/NC ... User_Guide

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    ou can use it with images sequences. 
For example, to convert the files file00.pic, file01.pic, ..., file10.pic and we convert to jpeg format with the name pattern res0.jpg, res1.jpg, ... type :
nconvert -out jpeg -n 1 10 1 -o res#.jpg file##.pic

[/color]

[XnTriq]

Hi cday
This is what I've got (so far):

You can use it with images sequences.
For example, to convert the files file00.pic, file01.pic, ..., file10.pic and we convert to jpeg format with the name pattern res0.jpg, res1.jpg, ... type :

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nconvert -out jpeg -n 1 10 1 -o res#.jpg file##.pic

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syntax-FOR-List of numbers
FOR /L %%parameter IN (start,step,end) DO command

<edit> Chapeau, Monsieur oops66 ! </edit>

[cday]

Hello ... A sample with option -n is into the xnview wiki, did not help?

http://www.xnview.com/wiki/index.php/NC ... User_Guide

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You can use [NConvert] with images sequences.
 
For example, to convert the files file00.pic, file01.pic, ..., file10.pic and ... to jpeg format with the name pattern res0.jpg, res1.jpg, ... type :

nconvert -out jpeg -n 1 10 1 -o res#.jpg file##.pic

[/color]

[Code edited to increase clarity.]

Thank you, that didn't show up in my searches, and the Wiki's are not a resource I normally think to turn to as they are often very limited or out of date.

That confirms the use of -n but I think I might have to do some tests to fully understand it...

[cday]

And thanks also to XnTriq whose usual wealth of links will hopefully provide some further insight...

[XnTriq]

Thank you, that didn't show up in my searches, and the Wiki's are not a resource I normally think to turn to as they are often very limited or out of date.

As it turns out, this info was transferred from Usage.txt to the Wiki.

You read the file with a serial number. Option is to condition such as "-n 1 15", "- n [start number] [end number]" Please enter in the format.

[oops66]

...Thank you, that didn't show up in my searches, and the Wiki's are not a resource I normally think to turn to as they are often very limited or out of date.
That confirms the use of -n but I think I might have to do some tests to fully understand it...

Hello Cday & Xntriq, you're welcome ... yes some others tests are needed too.

[cday]

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-n start end step : Begin End Step (for image sequence)

http://www.xnview.com/wiki/index.php/NC ... User_Guide[/url]

You can use [NConvert] with images sequences.

For example, to convert the files file00.pic, file01.pic, ..., file10.pic and ... to jpeg format with the name pattern res0.jpg, res1.jpg, ... type :

nconvert -out jpeg -n 1 10 1 -o res#.jpg file##.pic

I've been doing some [limited] tests and -n only seems to work correctly for step=1, depending on what behaviour is expected.

With 20 input files numbered test-01 to test-19 and step=2 only alternate input files are converted:

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nconvert -out png -n 1 20 2 -o Output-##.png test-##.png

Image_1.png

With end=40 again only alternate input files are converted, with an error message:

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nconvert -out png -n 1 40 2 -o Output-##.png test-##.png

Image_2.png

Am I missing something?

Edit

It looks as though step refers to the *input* file numbers, so there is no way to increment *output* file names other than by 1?

Wouldn't the expected behaviour be for all the input files to be processed, with the step applied to the output names?

That isn't really clear in the help file, if it is the case...

[cday]

Please see the edit added at the end of the previous post!

[oops66]

Please see the edit added at the end of the previous post!

... FYI, same issue uneder Linux version NCONVERT v6.17

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nconvert -out png -n 1 20 2 -o Output-##.png test-##.png

** NCONVERT v6.17 (c) 1991-2011 Pierre-E Gougelet (Sep 17 2012/10:50:01) **
        Version for Linux x86 (X11)  (All rights reserved)
** This is a freeware software (for non commercial use)

Conversion of test-01.png into Output-01.png OK
Conversion of test-03.png into Output-03.png OK
Conversion of test-05.png into Output-05.png OK
Conversion of test-07.png into Output-07.png OK
Conversion of test-09.png into Output-09.png OK
Conversion of test-11.png into Output-11.png OK
Conversion of test-13.png into Output-13.png OK
Conversion of test-15.png into Output-15.png OK
Conversion of test-17.png into Output-17.png OK
Conversion of test-19.png into Output-19.png OK
$ 
nconvert -out png -n 1 40 2 -o Output-##.png test-##.png
Conversion of test-01.png into Output-01.png OK
Conversion of test-03.png into Output-03.png OK
Conversion of test-05.png into Output-05.png OK
Conversion of test-07.png into Output-07.png OK
Conversion of test-09.png into Output-09.png OK
Conversion of test-11.png into Output-11.png OK
Conversion of test-13.png into Output-13.png OK
Conversion of test-15.png into Output-15.png OK
Conversion of test-17.png into Output-17.png OK
Conversion of test-19.png into Output-19.png OK
Conversion of test-21.png into Output-21.png OK
Conversion of test-23.png into Output-23.png OK
Conversion of test-25.png into Output-25.png OK
  Error: Can't open file (test-27.png)
  Error: Can't open file (test-29.png)
  Error: Can't open file (test-31.png)
  Error: Can't open file (test-33.png)
  Error: Can't open file (test-35.png)
  Error: Can't open file (test-37.png)
  Error: Can't open file (test-39.png)

[xnview]

-n replace ## by the range/step specified, in your test it works for step 2

[cday]

-n replace ## by the range/step specified, in your test it works for step 2

Thanks, could you please post an edited version of my command line?

[oops66]

-n replace ## by the range/step specified, in your test it works for step 2

Thanks, could you please post an edited version of my command line?

... I think Pierre's saying than the errors are normal, because -n replace ## (but only/mostly for the inputs files)

[cday]

I think Pierre's saying than the errors are normal, because -n replace ## (but only/mostly for the inputs files)

Well, O.K., but ## appears in two places in the command line...

But perhaps this shines at least a little light on a seemingly little known and probably rarely used NConvert option...

[oops66]

... But perhaps this shines at least a little light on an seemingly little known and probably rarely used NConvert option...

... Right, this -n option is not well explained into the help (nconvert -help), and the wiki example is not the good one too.