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 Jpeg wrong file size
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giancarlo

Italy
65 Posts

Posted - May 14 2013 :  02:57:35  Show Profile  Reply
I scan an image with imageenview and save it to a jpg file with 90 quality... i get about 1200kb
I scan the SAME image with other programs (faststone,irfanview,photoshop cs5) and saved with 90 jpg quality and i get from 300kb to 400kb
i all saved in 24bit depth and with the same resolution and dpi.
why so much file size difference?
also tried with/without "progressive" but the file size change few kb.

thank you

fab

1310 Posts

Posted - May 14 2013 :  06:59:42  Show Profile  Reply
Please could you post both (ImageEn and other program) resulting jpegs?
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giancarlo

Italy
65 Posts

Posted - May 14 2013 :  08:35:22  Show Profile  Reply
sure.
here the first pack of scans:

./attach/giancarlo/201351482857_scan_size_test_a.zip

the second pack

./attach/giancarlo/201351483133_scan_size_test_b.zip

i just notice that some program apply an automatic soft correction (contrast or brightness) before saving.
to avoid resize or resample differences, i've scanned the whole bed scanner space

thank you
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fab

1310 Posts

Posted - May 14 2013 :  09:22:51  Show Profile  Reply
You encoded ImageEn jpegs as RGB, while they should be YCbCr (as other programs do).
Try this:

ImageEnView1.IO.Params.JPEG_ColorSpace := ioJPEG_YCbCr;
ImageEnView1.IO.Params.JPEG_Quality := 90;
ImageEnView1.IO.SaveToFile('out.jpg');
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giancarlo

Italy
65 Posts

Posted - May 14 2013 :  09:51:54  Show Profile  Reply
yes, now the files are smaller.

thank you so much :)
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