JPEG lossless crop in NConvert?

Discussions on NConvert - the command line tool for image conversion and manipulation

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cosmin

JPEG lossless crop in NConvert?

Post by cosmin » Tue Oct 09, 2007 5:50 am

Hi,

I could not figure out how to use NConvert to do lossless JPEG cropping, the same way that I would do it from the XnView GUI. Is it not implemented, or is it just me not able to find it out?

Also, how is it possible to remove the EXIF thumbnail while leaving the rest of the image intact? (If I use -rexifthumb it recompresses the whole JPEG image; if I use -jpegtrans it seems to ignore -rexifthumb.)

Thank you for this wonderful piece of software!

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Cosmin

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xnview
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Re: JPEG lossless crop in NConvert?

Post by xnview » Tue Oct 09, 2007 6:52 am

cosmin wrote:I could not figure out how to use NConvert to do lossless JPEG cropping, the same way that I would do it from the XnView GUI. Is it not implemented, or is it just me not able to find it out?
Not yet implemented
Also, how is it possible to remove the EXIF thumbnail while leaving the rest of the image intact? (If I use -rexifthumb it recompresses the whole JPEG image; if I use -jpegtrans it seems to ignore -rexifthumb.)
Right, currently you can't
Pierre.

cosmin

Post by cosmin » Wed Oct 10, 2007 2:47 am

All right, then I will wait for it to be implemented :-)

Meanwhile, may I suggest to remove the thumbnail altogether when doing lossless cropping, even in XnView? If it's not possible (or easy to implement) to reconstruct it, it's better to discard it rather than keep the wrong one. Otherwise, it becomes confusing when the thumbnail shows one image and the contents is different, especially in a directory that's loaded with cropped images.

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Post by xnview » Wed Oct 10, 2007 7:09 am

cosmin wrote:All right, then I will wait for it to be implemented :-)

Meanwhile, may I suggest to remove the thumbnail altogether when doing lossless cropping, even in XnView? If it's not possible (or easy to implement) to reconstruct it, it's better to discard it rather than keep the wrong one. Otherwise, it becomes confusing when the thumbnail shows one image and the contents is different, especially in a directory that's loaded with cropped images.
Yes, right
Pierre.

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