PDA

View Full Version : change image bpp



hafidzhz
24.10.2017, 11:34 AM
is it possible to convert the image and lower its bpp?

Bhikkhu Pesala
24.10.2017, 05:57 PM
Command line options can be found in i_options.txt in the Program Files folder.

/bpp=BitsPerPixel - change color depth of the input image to BitsPerPixel

Example for /bpp:
i_view32.exe c:\test.jpg /bpp=8
Supported BPP-values: 1, 4, 8 and 24 (decrease/increase color depth)
=> Open 'c:\test.jpg' and reduce to 256 colors

hafidzhz
26.10.2017, 02:58 AM
Command line options can be found in i_options.txt in the Program Files folder.

/bpp=BitsPerPixel - change color depth of the input image to BitsPerPixel

Example for /bpp:
i_view32.exe c:\test.jpg /bpp=8
Supported BPP-values: 1, 4, 8 and 24 (decrease/increase color depth)
=> Open 'c:\test.jpg' and reduce to 256 colors

but im using iview64 *path* /convert *to path* / bpp = 1
the image still 8bpp

Mij
26.10.2017, 08:58 PM
You do not say why you want to reduce the image to 1 bpp. I use it to save scanned images as PDF files with small file size but because I want to apply saturation, contrast and brightness adjustments before reducing to 2 colours, I use the /advancedbatch command line option. The images are forms with handwritten entries and I get nice clear 1 bpp black and white images from a range of different coloured inks and line widths.

I use 32bit Irfanview to do this using the old IMPDF.DLL plugin to save the files. This could not be done with the 64bit Irfanview plugin at the time I set it up. I do not know if it is possible now. One thing that confused me at first was that if I tried to view the 1bpp PDF images in Irfanview they were always opened and displayed as 24bpp but I could tell from the file size that they were genuine 1bpp images that I was opening. I now always view them in a PDF program instead.