JPEG recompression automatization
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JPEG recompression automatization
Antonio, hello again! Thanks for PhotoFiltre, almost the second tool I use (after google chrome) Could you tell which algorithm is used to compress images to JPEG? It's one of the most accurate and strong algorithms. I usualy use "automation" to process photographies. PF can compress them in 10x or even more (4000*3000, 6 Mb -> 2000*1500, 250 Kb). Since I'm an IT-man too, I'd like to simplify this automation process to a few clicks, using PhotoFiltre comand-line parametres or only compresson algorithm (because I don't know any command line parametres for PF...)
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Re: JPEG recompression automatization
I don't know the algorithm, it is the native Delphi jpeg lib. It is a precompiled lib and i have not source.
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Re: JPEG recompression automatization
Oooou.. Surprise. And which Delphi version used?
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Re: JPEG recompression automatization
the V7 (very old version)
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Re: JPEG recompression automatization
Btw about Jpeg compression used by this library.
It uses by default YUV 122 component sampling, It's fast, the result jpeg file will be smaller, BUT IT'S too lossy for colors (especially red ones), as result - the image will be much blurry and lost many details. So even 100% quality in this mode - great loss of true colors. I myself use only AcdSee v3.0 for Jpeg compression, There I can chose the YUV better compressions method - YUV111. So If I chose 100% quality - The result photo should have NO changes at all.
Antonio, I recommend you to replace the Jpeg library you are using (OR if there are YUV 111 sampling option - to add it as option when compression percents asked)... If there are no such funtion - it's better to find another Jpeg compressor library.
Here you can look for example of compression quality loss:
http://coraksoft1.narod.ru/temp/YUV111/15okubok.png
(Original lossless Image in PNG)
http://coraksoft1.narod.ru/temp/YUV111/ ... yuv122.jpg
(Compressed 90% with YUV122 sampling, great loss of colors, 30% less file size, some blurring)
http://coraksoft1.narod.ru/temp/YUV111/ ... yuv111.jpg
(Compressed 90% with YUV111 sampling, no loss of colors)
It uses by default YUV 122 component sampling, It's fast, the result jpeg file will be smaller, BUT IT'S too lossy for colors (especially red ones), as result - the image will be much blurry and lost many details. So even 100% quality in this mode - great loss of true colors. I myself use only AcdSee v3.0 for Jpeg compression, There I can chose the YUV better compressions method - YUV111. So If I chose 100% quality - The result photo should have NO changes at all.
Antonio, I recommend you to replace the Jpeg library you are using (OR if there are YUV 111 sampling option - to add it as option when compression percents asked)... If there are no such funtion - it's better to find another Jpeg compressor library.
Here you can look for example of compression quality loss:
http://coraksoft1.narod.ru/temp/YUV111/15okubok.png
(Original lossless Image in PNG)
http://coraksoft1.narod.ru/temp/YUV111/ ... yuv122.jpg
(Compressed 90% with YUV122 sampling, great loss of colors, 30% less file size, some blurring)
http://coraksoft1.narod.ru/temp/YUV111/ ... yuv111.jpg
(Compressed 90% with YUV111 sampling, no loss of colors)