TIFF compression not working?

Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
Post Reply
muccigrosso
Posts: 62
Joined: 2017-10-03T10:39:52-07:00
Authentication code: 1151

TIFF compression not working?

Post by muccigrosso » 2018-09-04T11:22:50-07:00

Is there a problem with tiff group4 and fax compression? I'm having trouble getting good compression with them, and perhaps coincidentally these are the two compression schemes that were affected by this patch. For example,

Code: Select all

magick logo: -threshold 80% -alpha off -monochrome -compress METHOD -quality 100 output.tiff
gives me a 7k file when I use LZW as the method, but 39k for both fax and group4 (and for pbm), and some larger files I'm using aren't showing good compression with group4 and those other parameters. When I do `identify -verbose` the fax and group4 versions yield:

Code: Select all

Compression: None
whereas some files I did a few weeks ago show the expected compression value.

On a Mac, ImageMagick 7.0.8-11 Q16 x86_64 2018-09-01, --with-fftw --with-x11 --with-openjpeg.

User avatar
fmw42
Posts: 24139
Joined: 2007-07-02T17:14:51-07:00
Authentication code: 1152
Location: Sunnyvale, California, USA

Re: TIFF compression not working?

Post by fmw42 » 2018-09-06T16:18:27-07:00

I can confirm that there has been a change between 6.9.10.10 and 6.9.10.11 and also between 7.0.8.10 and 7.0.8.11 Mac OSX Sierra

In the latest versions, this command
magick logo: -threshold 80% -alpha off -monochrome -compress fax -type bilevel output.tiff
using magick identify -verbose

shows

compression=none

Same for -compress group4


This looks like a bug to me.

User avatar
dlemstra
Posts: 1513
Joined: 2013-05-04T15:28:54-07:00
Authentication code: 6789
Contact:

Re: TIFF compression not working?

Post by dlemstra » 2018-09-07T01:48:15-07:00

The fix for this will be available in the next release: https://github.com/ImageMagick/ImageMagick/issues/1297
.NET + ImageMagick = Magick.NET https://github.com/dlemstra/Magick.NET, @MagickNET, Donate

muccigrosso
Posts: 62
Joined: 2017-10-03T10:39:52-07:00
Authentication code: 1151

Re: TIFF compression not working?

Post by muccigrosso » 2018-09-25T11:51:02-07:00

This seems to be all fixed in IM 7.0.8-12.

Post Reply