Adjusting JPG format conversion settings
Today it is the most widely spread format for image storage and web publishing.
Read this article to learn more about this
format.
Settings of this format can be adjusted with the help of the following boxes.
Color depth equal to – use this dropdown list to select a color
depth.
Image quality – use these textbox and slider to set image quality.
Whole numbers from 25 to 100 are available. The higher is the specified value,
the higher is image quality and the larger is file size.
Additional settings of this format can be adjusted with the help of the following
boxes. They appear on the screen if you click more>> link.
With compression mode – use this dropdown list to select image
compression algorithm (read this article to learn more about compression algorithms).
Sample – use this dropdown list to specify channels of image
compression. Today most JPEG files have YcbCr format (where Y-channel stands
for brightness while Cb and Cr channels stand for color). Human eye is built
in such a way that it perceives brightness change of neighboring pixels first
and color change next. If we write an average true color image of photo quality
into JPEG format, we can skip every second horizontal value of color channels
and still have an image of nearly same quality. Each two pixels of the saved
image will have two values of Y channel and one value of Cb and Cr channels.
In ImageConverter Plus, this write mode is specified with “sample 4:2:2” parameter.
Below is the list of all available Sample values.
1:1:1 - YY CbCb CrCr, YY CbCb CrCr
4:2:2 - YY CbCb CrCr, YY .... ....
4:2:1 - YY CbCb Cr.., YY .... ....
4:4:2 - YY CbCb CrCr, YY CbCb ....
4:1:1 - YY Cb.. Cr.., YY .... ....
Create thumbnail - activate this checkbox to generate thumbnails
of processed images. Thumbnails are used to quickly preview images in browsers
and graphics viewers.
Save EXIF - activate this checkbox to copy EXIF (information
on shooting parameters of the camera used) to the resulting file, provided the
source file has this information.
Save IPTC - activate this checkbox to copy IPTC (metadata -
name, copyright, category) to the resulting file, provided the source file has
this information.
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