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Save High Resolution PNG to Disk is very slow

Oct 19, 2014 at 6:41 PM
I am really a new user to ImageMagick, please forgive me if a wrote something wrong
I wrote a simple code to convert a 40 Megapixel image from JPEG to PNG, here is the code
            using (MagickImage image = new MagickImage("path/test.jpeg"))
            {
                image.Write("E:/test.png");
            }
These lines of code took 231.959 seconds to execute. I am using the "Magick.NET-7.0.0.0003-Q16-AnyCPU-net40-client" version of ImageMagick.net.
Is there anything wrong with my code? Am I missing something? Or ImageMagick takes this much amount of time for PNG conversion in real?
Oct 20, 2014 at 9:04 PM
When I read this on my machine it reads the image in 1 second and takes 22 seconds to write the image. The reason the png writer is taking so long is probably due to the fact that is is compressing the image. This is still nowhere near your duration. Are you doing the conversion on a really old machine? It is also possible that Magick.NET cannot allocate enough memory and uses the disk. What is the amount of memory in your machine? I ran my tests on a machine that has an Intel Core I3-2120 and 8GB of ram.
Oct 21, 2014 at 8:42 AM
My machine has Intel Core-i7 processor with 8GB RAM
Oct 21, 2014 at 9:16 AM
Edited Oct 21, 2014 at 9:16 AM
And it takes 2 minutes to read and write the image (40MP.jpg)?
Oct 21, 2014 at 11:27 AM
The processing time (22 seconds) you shared earlier encourage me to carry some more tests. I had Windows 8.1 installed on my machine. I got a surprising result after testing the same application on Windows 7 the processing time reduced to 25 seconds.
What is the reason of this huge time difference between the two operating systems?
Oct 21, 2014 at 11:35 AM
I test out the application with assigning different values to image.Quality and the processing time variation from 25 seconds to 60 seconds
       image.Quality = 100;
What should be the maximum and minumum value of image quality property?
Oct 21, 2014 at 12:33 PM
If you are writing a PNG file the value of the Quality is not as simple as you might think. I posted a detailed explanation here: https://magick.codeplex.com/discussions/569689#post1314107.