search

dropbox / lepton

Lepton is a tool and file format for losslessly compressing JPEGs by an average of 22%.
https://blogs.dropbox.com/tech/2016/07/lepton-image-compression-saving-22-losslessly-from-images-at-15mbs/
Apache License 2.0
5.01k stars 355 forks source link

Some JPEG files become even larger after lepton compression #64

Closed sp-1234 closed 8 years ago

sp-1234 commented 8 years ago

Example: https://cloud.githubusercontent.com/assets/1442206/17919118/005ee04c-69dc-11e6-83e0-4d027edfb399.jpg

It gives 102% (bigger file)

danielrh commented 8 years ago

With lossless compression, by the pigeon hole principle, if some files can compress smaller then others, necessarily, must be bigger

here's a more detailed explanation http://web.stanford.edu/class/archive/cs/cs103/cs103.1132/lectures/08/Small08.pdf

magicgoose commented 8 years ago

but it can store uncompressable data literally, like does LZMA2 for example, right?