JPEG 2000 libraries for Ruby

Ruby has no pure-Ruby JPEG 2000 codec. Use a binding of a C library:

• ruby-vips binds libvips, which reads and writes JPEG 2000 through OpenJPEG. It’s fast, uses little memory and can load a lower resolution level of a large file directly. It’s also the default processor in Rails Active Storage (through image_processing).

MiniMagick works too if ImageMagick is built with OpenJPEG: it runs the magick command line.

• ruby-vips ruby-vips reads and writes JPEG 2000 in Ruby through libvips and OpenJPEG. How to install it, convert JP2 to PNG, save lossy.