Filesize doubles with batch-editing

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infosauger
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Filesize doubles with batch-editing

Post by infosauger »

When I open a picture (jpg) with a rotation Info and just safe it (lossless settings) the filesize just changes to slightly smaller (Example: Original 4MB -> 3,62MB).
When I rotate the same picture in one direction and back, the size changes to 3,86MB.
When I start a batch job and set the editing to rotate to EXIF-Direction with the same settings for jpg (lossless) the filesize changes from 4MB to 10MB.
I tried to find a pixel difference with GIMP between the Original and the new file but didn’t find anything. What uses this extra space?
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xnview
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Re: Filesize doubles with batch-editing

Post by xnview »

Do you means batch lossless transformations or batch convert?
Pierre.
infosauger
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Re: Filesize doubles with batch-editing

Post by infosauger »

right click on picture -> batch convert -> action: rotate (EXIF Orientation) -> output: Format (same as original); settings (JPEG: 100%; JPEG-XR: 100%; JPEG-XL: lossless compression)

Original picture: JPEG TrueColor (c1.1)
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xnview
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Re: Filesize doubles with batch-editing

Post by xnview »

your original picture is perhaps not compressed at 100%
Pierre.
infosauger
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Re: Filesize doubles with batch-editing

Post by infosauger »

xnview wrote: Tue Nov 09, 2021 11:16 am your original picture is perhaps not compressed at 100%
Hm, if the original picture isn't compressed at 100% but the target one is, shouldn't then the target file be much smaller instead of much larger?
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xnview
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Re: Filesize doubles with batch-editing

Post by xnview »

if you original file is compressed for example to 70, if you compress it at 100% you'll have a higher file size
Pierre.
infosauger
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Re: Filesize doubles with batch-editing

Post by infosauger »

xnview wrote: Mon Nov 08, 2021 7:21 am Do you means batch lossless transformations or batch convert?
Lossless transformation is the only rotation option, that is not lossless. It cuts Pixels on the border.
The other 3 rotation options (1: Save picture in picture window; 2: Batch transformation with rotation action; 3: export to JPG) result in 100% ident images (checked with GIMP) but complete different filesizes: Original File: 3,79MB; Option 1: 3,16MB; Option 2: 9,45MB; Option 3: 6,52MB.
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xnview
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Re: Filesize doubles with batch-editing

Post by xnview »

"batch convert -> action: rotate (EXIF Orientation)" is not lossless, only "JPEG lossless transformations"
Pierre.
infosauger
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Re: Filesize doubles with batch-editing

Post by infosauger »

xnview wrote: Wed Nov 10, 2021 7:31 am "batch convert -> action: rotate (EXIF Orientation)" is not lossless, only "JPEG lossless transformations"
Sorry, but that's wrong.

I tried JPEG lossless transformations and width changed from 2988 pixels to 2984 pixels. The remaining picture is 1:1 with the original
I also tried "batch convert -> action rotate (EXIF Orientation) with 100% quality and the picture is 1:1 with original.

I opened both files and the original with GIMP and there is no pixel-difference except the 4 pixels on the right side after "JPEG losless transformation".

Maybe there is a setting for "JPEG lossless transformation" that it doesn't cut the picture, but I didn't find it.
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xnview
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Re: Filesize doubles with batch-editing

Post by xnview »

infosauger wrote: Wed Nov 10, 2021 10:22 am I tried JPEG lossless transformations and width changed from 2988 pixels to 2984 pixels. The remaining picture is 1:1 with the original
Lossless rotation need that width is a multiple of 8, Batch convert re-compress image data
Pierre.
infosauger
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Re: Filesize doubles with batch-editing

Post by infosauger »

xnview wrote: Wed Nov 10, 2021 11:14 am Lossless rotation need that width is a multiple of 8, Batch convert re-compress image data
I understand, but why doesn't re-compress need a multiple of 8? Batch convert a landscape image with EXIF rotation info results in a 100% pixel-ident and 100% resolution-ident portrait image without EXIF rotation info.
Lossless rotation can result in loss of pixels, though the remaining pixels are 100% ident with the original. in my opinion calling it lossless when data is lost is just wrong.
Opening a landscape picture with EXIF rotation info is correctly shown as portrait. Just saving this picture results in a portrait image without EXIF rotation info and without loss of pixels it is 100% pixel ident with the original. It would be better if Lossless rotation would work exactly like this.
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xnview
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Re: Filesize doubles with batch-editing

Post by xnview »

it's the way that lossless rotation works, encoded datas are not changed.
You can make lossless rotation by changing only the EXIF field
Pierre.
infosauger
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Re: Filesize doubles with batch-editing

Post by infosauger »

xnview wrote: Wed Nov 10, 2021 1:29 pm it's the way that lossless rotation works, encoded datas are not changed.
You can make lossless rotation by changing only the EXIF field
Why doesn't batch rotation or lossless rotation work like "open picture->save picture"? As I mentioned, this way is really lossless, it doesn't cut pixels and the image is 100% ident with the original? And the filesize is simalar to the original one. But it takes time for many pictures.
All other ways generate 100% ident image, but need much more space.
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xnview
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Re: Filesize doubles with batch-editing

Post by xnview »

batch convert & Save are not lossless, image datas are recompressed, but if you use 100% quality, there is no big loss
Pierre.
infosauger
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Re: Filesize doubles with batch-editing

Post by infosauger »

xnview wrote: Fri Nov 12, 2021 7:05 am batch convert & Save are not lossless, image datas are recompressed, but if you use 100% quality, there is no big loss
Wrong. I checked the Original picture with each version of the target picture with GIMP and THERE ARE NO PIXEL DIFFERENCES.
So they images are completley the same.