Search found 4729 matches

by XnTriq
Tue Jan 26, 2021 9:00 pm
Forum: Miscellaneous
Topic: RIOT — Radical Image Optimization Tool
Replies: 21
Views: 15816

Re: RIOT — Radical Image Optimization Tool

[+] 64 bit version, allowing bigger images to be processed (>50 MP) [!] improved compression with up to 30% for jpeg images [+] decoding support for jpeg images using arithmetic coding [+] improved PE security with DEP and ASLR [!] the AVX2 instruction set for the 64bit version should provide bette...
by XnTriq
Tue Jan 26, 2021 6:00 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

Danke for reporting back, Peter! @Pierre: What's the value range of nConvert's -q parameter (0-99 or 1-99 or 0-100 or 1-100) :?: Ranges of quality settings differ in each implementation, but the IJG values range from 99 (best) to 1 (worst). Please note that these are not percentages , nor is there a...
by XnTriq
Sun Jan 24, 2021 9:45 am
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

I apologize for hijacking your thread, Peter https://newsgroup.xnview.com/images/icons/smile/redface.gif The idea behind it is that I use "nconvert.exe" to add text in multiple lines. Because (at the moment) there is no multiline-feature, I have to repeat "write line - save jpg - write line - save ....
by XnTriq
Sun Jan 24, 2021 9:00 am
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

Compare the two images, is the lower image obviously quite unusable as predicted? Zooming in, it is possible to see some slight loss of quality, but doesn't the image above remain quite usable for any reasonable purpose? While the (loss in) quality may be acceptable to you and me, most serious phot...
by XnTriq
Sat Jan 23, 2021 10:30 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

Thank you very much, cday :-D I'll get back to you ASAP!
by XnTriq
Fri Jan 22, 2021 10:45 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

The XnView file 'info' displays 'Subsampling', so in principle that could be read and an image resaved using Use estimated original quality (when possible) with the same subsampling, even if you say that is not implemented now? Could you please rephrase or elaborate on your question, cday? Filename...
by XnTriq
Fri Jan 22, 2021 10:15 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

Original image<br />www.cambridgeincolour.com/tutorials/bit-depth.htm
Original image
www.cambridgeincolour.com/tutorials/bit-depth.htm
0_original.png (72.62 KiB) Viewed 76 times

Original PNG converted with XnView to JPEG (no chroma subsampling)
Original PNG converted with XnView to JPEG (no chroma subsampling)
1_converted.jpg (94.87 KiB) Viewed 76 times
Conversion settings
Conversion settings

Converted JPEG resaved with XnView (default chroma subsampling)
Converted JPEG resaved with XnView (default chroma subsampling)
2_resaved.jpg (55.25 KiB) Viewed 76 times
Resave settings
Resave settings

Converted and resaved JPEGs compared with Image Comparer<br />www.softpedia.com/get/Multimedia/Graphic/Graphic-Others/Image-Comparer.shtml
Converted and resaved JPEGs compared with Image Comparer
www.softpedia.com/get/Multimedia/Graphic/Graphic-Others/Image-Comparer.shtml
3_diff.png (21.24 KiB) Viewed 76 times
by XnTriq
Thu Jan 21, 2021 11:30 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

And if Use estimated original quality (when possible) is used? 0.85*0.85*0.85 = 61%? Or close to no additional loss? It depends. Let's say your JPEG that was previously saved without chroma subsampling i.e. 1×1,1×1,1×1 (best quality) . Re-saving/re-encoding this JPEG with a SubSampling factor of 2×...
by XnTriq
Thu Jan 21, 2021 10:15 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

When I save a JPG file with "quality 100%", it results in an unmodified quality. This is a common misconception. Most of us had to learn the hard way that re-encoding a JPEG is always lossy. A Quality Setting of 100 Does Not Degrade an Image at All: False Saving an image to JPEG format always intro...
by XnTriq
Thu Jan 21, 2021 8:30 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

I'm always hoping for a "yes/no" answer and I'm always afraid when XnTriq starts his IKM (incredible knowledge machine). I'd love to give you a straightforward answer, but when it comes to JPEG, there's no one-size-fits-all solution. It's the nature of the beast :-| Initiating yet another BLS ( b i...
by XnTriq
Tue Jan 19, 2021 10:00 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

Useful software for analyzing and editing JPEGs: Independent JPEG Group jpg*dexe.zip = cjpeg/djpeg + rdjpgcom/wrjpgcom + jpegtran “Binaries for Win32 compatible systems of sample applications of the Independent JPEG Group's free JPEG software” Jpegcrop “The Jpegcrop Windows Application was initially...
by XnTriq
Tue Jan 19, 2021 6:45 pm
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

Wikipedia: Although a JPEG file can be encoded in various ways, most commonly it is done with JFIF encoding. The encoding process consists of several steps: The representation of the colors in the image is converted to Y' C_B C_R , consisting of one luma component (Y'), representing brightness, and ...
by XnTriq
Tue Jan 19, 2021 3:00 am
Forum: Classic - General Support
Topic: Basic understanding of "JPEG Quality"?
Replies: 23
Views: 508

Re: Basic understanding of "JPEG Quality"?

XnTriq is, of course, the expert on all these matters... foxyshadis is our resident expert b/c she understands the math behind it :-) Forum references regarding the JFIF/JPEG file format: JPEG compression as lossless as possible Standard Values for JPG-Compression and EXIF/IPTC settings a picture p...
by XnTriq
Sun Jan 17, 2021 5:30 pm
Forum: NConvert
Topic: Downsampled image has lower quality than expected
Replies: 8
Views: 369

Re: Downsampled image has lower quality than expected

stickynoteme's source.jpg converted to PNG and downsampled from 447×447 to 333×333 pixels with… XnView Classic (Bilinear + Lanczos) XnView MP (Lanczos) XnConvert (Lanczos) nConvert (Lanczos) PhotoFiltre (Lanczos) IrfanView (Lanczos) FastStone Image Viewer (Lanczos3 + Lanczos2) Photoshop CS2 (Bicubic...
by XnTriq
Sat Jan 16, 2021 10:00 pm
Forum: NConvert
Topic: Downsampled image has lower quality than expected
Replies: 8
Views: 369

Re: Downsampled image has lower quality than expected

Lanczos3 is available in XnView/NConvert, so i can add it easily in GFL SDK & GFLAx. -rtype : Type of resampling quick : Quick resize linear : Bi-linear (linear) hermite : Hermite gaussian : Gaussian bell : Bell bspline : Bspline mitchell : Mitchell lanczos : Lanczos -sharpen percent : Sharpen (1.....