JPEG compressor algorithm
How can I get JPEG compression for maximum quality in a minimum file size?
Alike Adobe Photoshop compression or Advanced JPEG Compressor ?
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You could compute a difference map (e.g. subtract each pixel of the original image from the newly packed an unpacked temporary JPEG). Then compute the average difference of all pixels alltogether and choose a value that you consider to be acceptable for "good quality" using this difference.
Now do this with a binary search approach so long until you get to the optimal value for that particular image.
This can be used as method to find the optimal % value for a particular image to be compressed to JPG.
Now do this with a binary search approach so long until you get to the optimal value for that particular image.
This can be used as method to find the optimal % value for a particular image to be compressed to JPG.
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Sorry for delay :)
Usually JPGs are compressed at 80%
You may change this using the suggestion above and the classical StretchDraw aftet Bitmap.Assign (see "how to make a thumbnail" somewhere)
For the REAL algorithm itself, It should be findable using google (Huffman? Alike LZW? )