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Input / Output for JPG lossless conversions
Posted: Sun Jan 09, 2011 11:33 pm
by helmut
JPG lossless conversions are directly applied on the original file, no output file is generated. This is confusing and a real breach in the clear and simple input/output concept of nconvert.
I wonder whether JPG conversions couldn't be handled as any other transformation: The original file could be copied and then the lossless transformation on the copied file could be applied. This way, the input/output concept of nconvert could be maintained while the JPG conversion still directly works on the file.
Re: Input / Output for JPG lossless conversions
Posted: Mon Jan 10, 2011 6:45 pm
by maesehn
Hi,
helmut wrote:
The original file could be copied and then the lossless transformation on the copied file could be applied.
Actually i found a trick that allows you to do so. If you set an ouput name then the lossless transformation is applied to the output file not on the source:
Code: Select all
nconvert.exe -jpegtrans exif -o picture-#.jpg *.jpg
It seems that the “-jpegtrans” switch was not coded to only
apply-transformation-to-the-source-file. It's only its default behavior: if it founds a counter-order (“set an output name” in the exemple above) then it is able to (it knows how to) apply the transformation to the output file. That's different from what we thought at first!
But that's not all, we discovered that there are
more problems with this switch: it's impossible to run a resize command at the same time for example…
helmut wrote:
This is confusing and a real breach in the clear and simple input/output concept of nconvert.
I agree. Not only the transformation is applied on the source file but the program don't ask a human confirmation for overwriting to the files (Unlike other conversions that need for the “-overwrite” switch).
Everything should be in harmony!
Re: Input / Output for JPG lossless conversions
Posted: Mon Jan 10, 2011 8:20 pm
by marsh
maesehn wrote:
Everything should be in harmony!
I think splitting it into 2 programs could be useful for that.
Re: Input / Output for JPG lossless conversions
Posted: Thu Mar 03, 2011 10:04 am
by xnview
Re: Input / Output for JPG lossless conversions
Posted: Sat Mar 05, 2011 3:50 am
by marsh
In v.5.85, jpeg lossless function can now create a seperate file!
Ex.
nconvert.exe -jpegtrans rot90 -o output.jpg input.jpg
(this one did not change original)
And overwriting original is still possible when no output file is specified.
Ex.
nconvert.exe -jpegtrans rot90 -overwrite test.jpg
(without overwrite command, it does not change original)