#35 Support zopfli

open
Cosmin Truta
None
5
2015-04-16
2013-03-04
Anonymous
No

https://code.google.com/p/zopfli/

Increase compression ratio of deflate stream

Discussion

  • Cosmin Truta
    Cosmin Truta
    2013-11-04

    • assigned_to: Cosmin Truta
    • Group: --> Next Release (example)
     
  • Cosmin Truta
    Cosmin Truta
    2013-11-04

    This is on my to-do list.

     
  • Ian
    Ian
    2013-11-07

    I've run quite a lot of images through advpng (the advancecomp utility that offers zopfli and 7-zip compression of some png formats) and I didn't get a huge amount from it. Many files wouldn't go smaller and the ones that did were just a few percent. Possibly the 5%-10% advertised improvement is not relative to the best that optipng can already achieve?

     
  • Cosmin Truta
    Cosmin Truta
    2013-12-29

    Ian, among the images you tested, how many of them are compressed with delta-filtering different than 0 (None)? You can use "pngcheck -vv" to find that out.
    Wondering if zopfli is probably not that much better than Z_FILTERED, in the situations where Z_FILTERED is applicable.

     
  • Ian
    Ian
    2013-12-29

    Some are filtered. Most are not.

     
  • fua1eiga
    fua1eiga
    2015-03-10

    Two years and one release later I wonder if this is still on the list..?

    OptiPNG with the new -strip option and Zopfli built in would leave little for me to be desired. Only one tool for the usual PNG optimization workflow? - hell yeah, I want that!

     
  • fua1eiga
    fua1eiga
    2015-04-11

    Maybe some crucial bit of information:
    (The Zopfli mode of) advpng seems to be buggy. For some reason it performs much worse than the official ZopfliPNG. I get a solid 17 % difference in filesize here.
    So maybe it's worth reevaluating Zopfli another way than through advpng.

     
  • fua1eiga
    fua1eiga
    2015-04-16

    advpng does not support any delta filtering (i.e. only filter type 0).