Dropbox releases open source software 'Lepton' that can compress JPEG images by 22% with losslessness

Image data that tends to be stored in large quantities is where you want to keep the file size as small as possible. Cloud service Dropbox is free software that can compress JPEG image data by 22% on average without deteriorationLepton"Has been released. For Lepton, it is possible to use "reduce the JPEG image file size and decompress quickly only when actually using it".

Lepton image compression: saving 22% losslessly from images at 15 Mb / s | Dropbox Tech Blog
https://blogs.dropbox.com/tech/2016/07/lepton-image-compression-saving-22-losslessly-from-images-at-15mbs/

Dropbox, which provides cloud storage services, has been forced to reversibly compress a large amount of JPEG data that the user saves, so we developed a software "Lepton" with its own high compression ratio. Distribution of the compression ratio which compressed JPEG data using Lepton is as follows, meaning that the file size can be reduced by an average of 22%.


Dropbox is using GitHub with Lepton that is used for its own service. Lepton is open source software, so you can use it free of charge.

GitHub - dropbox / lepton: Lepton is a tool and file format for losslessly compressing JPEGs by an average of 22%.
https://github.com/dropbox/lepton

So, I immediately compressed the image using Lepton. In the tests I used the original size of the following pictures and the file size was about 6.5 MB.


Run the Lepton program on Linux and compress the file "lepton-sample.jpg" into a file called "lepton-sample.lep".


Compression completed in just a few seconds. The file size became about 5.3 MB, the compression ratio was 81.9%, and the file size became about 18% smaller.


Next, decompress the compressed file "lepton-sample.lep" and return it to the JPEG file "original.jpg".


Defrosting completed in a few seconds.


When comparing the original file with the file which decompressed, naturally the same image was displayed.


Even comparing file sizes was exactly the same.


Lepton is able to compress JPEG images by 22% on average, and because compression and decompression speeds are also very fast, Dropbox has already been put into practical use in service. It seems that 16 billion JPEG data saved in Dropbox are being sequentially compressed with Lepton.