Search found 75 matches

by Marsu42
2019-02-18T02:08:11-07:00
Forum: Users
Topic: Possible to detect compression artifacts?
Replies: 2
Views: 2120

Re: Possible to detect compression artifacts?

This suggests we can analyse an image to detect and measure JPEG artifacts, and compare two JPEGs for "badness", and test other images for the presence of artifacts. But I haven't investigated this. Somehow, I feel this problem should have come up before - esp. with new lossy formats on the rise it...
by Marsu42
2019-02-18T02:00:15-07:00
Forum: Users
Topic: How to determine if a lossless image was a jpeg?
Replies: 2
Views: 1568

Re: How to determine if a lossless image was a jpeg?

snibgo wrote:
2019-02-12T05:27:04-07:00
I think looking for patterns in blocks might work. See my reply at https://www.imagemagick.org/discourse-s ... 5&p=157734
Thanks, so this thread is a dupe, I'll continue discussing in the other one.
by Marsu42
2019-02-12T05:16:45-07:00
Forum: Users
Topic: How to determine if a lossless image was a jpeg?
Replies: 2
Views: 1568

How to determine if a lossless image was a jpeg?

This isn't im-specific, but I hope this can be done with some im magic or at least some folks can help otherwise: I'm processing lossless images (png, tif, lossless webp) and am looking for a way to determine if it actually was a lossless format (i.e. jpeg most of the time) once. Visually, this is m...
by Marsu42
2017-03-17T14:41:25-07:00
Forum: Developers
Topic: Plz add Google's Guetzli encoder in addition to libjpeg
Replies: 0
Views: 13578

Plz add Google's Guetzli encoder in addition to libjpeg

I've become a supporter and user of (esp. pre-processed lossless) webp, but with more computing power there are obviously still improvements even in ancient formats... behold, Google strikes again: https://research.googleblog.com/2017/03/announcing-guetzli-new-open-source-jpeg.html Guetzli is a JPEG...
by Marsu42
2016-10-10T14:48:30-07:00
Forum: Developers
Topic: Request: add portable.7z files to download set
Replies: 1
Views: 3895

Re: Request: add portable.7z files to download set

I'm observing that the most downloaded files from SourceForge are the *portable.zip files; I think it would be worthwhile adding *portable.7z to save some wear and tear on the Internet, being less than half the size (31.6MB versus 74.8MB). We're talking about the same Internet here, the one with al...
by Marsu42
2016-10-09T11:18:59-07:00
Forum: Developers
Topic: FLIF lib 0.2 update
Replies: 4
Views: 5371

Re: FLIF lib 0.2 update

What do you mean by complex delegate requirements? My experience with compiling im was that it's not a matter of configure and make, but to get all file formats inside you have to hunt down and install a lot of libs. That's why I'm happy that there are complete and updated binary releases of im all...
by Marsu42
2016-10-08T02:43:13-07:00
Forum: Developers
Topic: FLIF lib 0.2 update
Replies: 4
Views: 5371

Re: FLIF lib 0.2 update

We upgraded flif to 0.2. My guess is that it was no longer working because metadata was added. Thanks - I guess the reason that it doesn't appear in the git log (http://git.imagemagick.org/repos/ImageMagick/activity) is that you just updated the .h and the .c (http://git.imagemagick.org/repos/Image...
by Marsu42
2016-10-07T17:48:41-07:00
Forum: Developers
Topic: FLIF lib 0.2 update
Replies: 4
Views: 5371

FLIF lib 0.2 update

IM doesn't seem to feature the latest FLIF format 0.2 - images generated by im cannot be read by the Windows Explorer plugin (based on the 0.2 lib), while images converted with flif's own command line encoder can. If so, please update - thanks. https://github.com/FLIF-hub/FLIF/releases https://githu...
by Marsu42
2016-10-07T07:49:38-07:00
Forum: Users
Topic: How to "best fit" (crop/resize)
Replies: 8
Views: 8520

Re: How to "best fit" (crop/resize)

Hope someone can help me, thanks You need to somehow calculate the exact part that you want to crop, I'm doing this outside im with a shell script after reading the image props. Then set the gravity % crop this area, then resize. Lookie here under "{size}{+-}x{+-}y": http://www.imagemagick.org/scri...
by Marsu42
2016-10-07T05:02:28-07:00
Forum: Developers
Topic: Versioning policy (Windows installer in-place updates)
Replies: 2
Views: 3967

Re: Versioning policy (Windows installer in-place updates)

This should be possible with InnoSetup. Thanks for looking into it, the current installer oddities don't make im appear like the excellent software it is. At the same time, could you please address another tiresome problem: When in-place updating the Windows installation, the setup asks if it shoul...
by Marsu42
2016-10-07T03:39:54-07:00
Forum: Developers
Topic: Versioning policy (Windows installer in-place updates)
Replies: 2
Views: 3967

Versioning policy (Windows installer in-place updates)

Looking at http://www.imagemagick.org/script/changelog.php the version numbers of im seem completely random - esp. when a change of 7.x.y to 7.x.y+1 occurs or when it's just a 7.x.y-z to 7.x.y-z+1 step. The annoyance is that with a minor version number change, the Windows installers refuse to do an ...
by Marsu42
2016-10-07T03:28:29-07:00
Forum: Bugs
Topic: Odd behavior with "-composite" in IM 7.0.3 ?
Replies: 2
Views: 3078

Re: Odd behavior with "-composite" in IM 7.0.3 ?

The requirement for "-alpha on" after "xc:none" seems to be a new bug/feature introduced since 7.0.2-5. Thanks for crossposting to the bugs subforum, as a mere user it's difficult to figure out if it's a bug or one is merely not using im correctly. Even if this change *would* make sense, it shouldn...
by Marsu42
2016-10-07T03:20:15-07:00
Forum: Developers
Topic: JPEG XT
Replies: 0
Views: 7297

JPEG XT

The new jpeg spec can be read by legacy decoders and additionally supports ... * 9-16 bpp int * fp ("hdr") * lossless * alpha (at last!) The libjpeg already seems to have support for it(?), so how about an im delegate for jpxt? https://jpeg.org/jpegxt/index.html https://jpeg.org/jpegxt/software.html...
by Marsu42
2016-10-03T11:13:28-07:00
Forum: Developers
Topic: JPEG XR support question
Replies: 10
Views: 15173

Re: JPEG XR support question

But apparently all the images are from JPG files, which are then converted to the other formats. What makes you say that, and "apparently". I just assumed that of course the source is a lossless file and then compressed to the various destination formats - it's not like it's difficult to acquire a ...
by Marsu42
2016-10-03T04:54:14-07:00
Forum: Developers
Topic: JPEG XR support question
Replies: 10
Views: 15173

Re: JPEG XR support question

BPG image format would be great except no browsers support it: http://caniuse.com/#search=bpg Yeah, well, but if *some* windows-only browsers support xr and the rest is WONTFIX, that's basically "none" in real life: http://caniuse.com/#search=jpegxr https://bugs.chromium.org/p/chromium/issues/detai...