2018.05.14 13:20 "Re: [Tiff] LZ4 compression", by Bob Friesenhahn

>
>> One other alternative is use of filesystem-level compression.
>
> This is a good experiment.
> It shows LZ4 doesn't have good compression ratio comparted to gzip or other compression method for archiving.
> LZ4 is focused on encoding and decoding speed. That's why LZ4 is adapted on ZFS file system. The better compression method for TIFF should have good balancing between decoding performance and transferring performance, which equals to compression ratio. Because TIFF is always decoded and viewed on viewer applications.

While LZ4 file compression performance in zfs is interesting, it is not very indicative of how well it would do on raster data as implemented in libtiff. The reason why it is not very very indicative is that the filesystem is a general-purpose mechanism without any knowlege of the content (e.g. TIFF strips/tiles) and with an underlying block size not related to the image data.

It is easy to implement LZ4 inside the operating system kernel space but ZStd is likely too complex to port into such an environment.
Regardless, ZStd compresses much faster than gzip while achieving a better compression ratio on raster data.

> Anyway, it looks like Adobe is the key person. If Adobe implements
> LZ4 compression on Photoshop, LZ4 TIFF will become a common format.

Adobe is no longer pushing or promoting TIFF and it is unlikely to
implement any more extensions to TIFF. It is not clear to me that
Adobe's Photoshop is as dominant as it used to be.

> BTW, TIFF is still common in the printing industry since TIFF

> supports CMYK images that can represent printing device output.

> That's why I'm seeking LZ4 TIFF option.

Adobe promotes PDF for such applications.

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/