![]() The middle set of files were generated by running the above scriptĪgainst the original files with a scaling factor of 0.5. The leftmost files are the original files. The following screen snapshot attempts to show compression results in UPDATE: This section added to original post based on feedback from Eric Wendelin (see below). Libraries such as Java Advanced Imaging API, ImageMagick, or imgscalr might have made the script even more concise. Uses the ImageMagick convert command to do the. That all images provided to be compressed are already JPEG format. Discusses how applying JPEG compression MULTIPLE TIMES to an image affects the quality of the image. Scaling factor is a numeral between 0 and 1. files using tools such as FFmpeg and convert from the ImageMagick suite. There could be better checks to verify that the provided Video codecs compress the individual frames as well as exploiting redundant. Groovy's built-in CLI-basedĬommand-line support could be used for nicer handling of command-line This script was sufficient for my needs, but there are many ways it could be improved. The files are written as JPG files and are scaled by In my experience, Imagemagick is the best image compressor program, and it gives one the most control over how to compress images. The newĭirectory is named by concatenating the milliseconds since epoch timeĪfter "backup_". Instead re-writes them with the same name to a new directory. The Groovy script above does not change the input image files, but Writer.write(null, image, imageWriteParameters) "ĭef output = new FileImageOutputStream(targetFile) ĭef image = new IIOImage(sourceImage, null, null) Println "\t is scaling factor for reduced image (0 to 1)" Println "\twhere is directory from which image files come" Have been more concise had I used the Java Advanced Imaging API, but that would have meant another separate dependency. See if I could reduce required dependencies. I decided to write a similar script using straight Java and Groovy to Noted that Eric Wendelin had posted Crush images on the command-line with Groovy that demonstrates using Groovy in conjunction with ImageMagick to " images the Groovy way." This looks like an easy and attractive way to do it, but it requires ImageMagick and, if on Windows, Cygwin. JPG -compress Zip output.pdf but the zip compression appears quite. Theseĭays, Groovy is my generally my preferred tool for scripting jobs. ImageMagick is a command-line of so many more batch operations than this - resizing. Manipulation tool, so scripting seemed like the obvious choice. I did not want to do this one at a time in a graphics "-e 9 -E 3 -patches 1" can be very demanding though, I usually compress my images in parallel, 1 thread per file, 16 files at once, both the jpgs and the minecraft screenshots took hours to complete (the jpgs were much smaller and jpg transcoding is a lot faster than VarDCT/modular compression options)Įdit: I forgot, the minecraft screenshots I compressed only 4 at once, because the 10k images required a lot of ram, that's about the most I could do with 32 GiB of memory and those options.I recently had need to reduce the size of a large number of JPG I haven't tried jxl much for lossy encoding but I think it's not bad either, if you care about quality first and size second. įrom my own testing I can tell you I'm quite happy with jxl for lossless images and jpg recompression, with "-e 9 -E 3 -patches 1" (idk if that's the most dense option) it saved me about 30% on 12461 jpgs (that was with an old version from December) and 77% (from 410 MiB to 94 MiB) on 25 lossless screenshots from minecraft, most in 10k resolution with a lot of noise. It will look more appealing at lower bpp, but fares worse at high fidelity. Webp is based on a video codec, VP8, so it might have lower sizes, but it will for example smooth out textures. The lossless transcode to jxl from jpg should give you about 15-30% size reduction, depending on the content and settings used, unless you have already optimized the jpegs, that is progressive jpg/arithmetic coding. These tools allow you to specify the compression settings and. ![]() ![]() Since you are transcoding from jpg, a lossy codec, it has an advantage against jxl and webp (you could use the lossless transcoding option in jxl, the defualt for cjxl, no idea for imagemagick, to mitigate it a little bit), since the jpg encoder had more information to work with than jxl and webp do now. Command-line tools such as ImageMagick can compress JPG images for more advanced users. I've just run a test on 60 jpgs and cjxl on default settings was simillar in size to imagemagick, from 73.4 MiB to 62.1 MiB and 61.3 MiB for cjxl and imagemagick respectively, although of course I can't open the latter ones. I think there's something wrong with imagemagick (v 7.1.0.1-1), the images it creates can not be decompressed on my system by djxl. use butteraugli to make the images with approximately the same quality and then compare sizes. ![]()
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