Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion. Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules. |
|
|
Thread Tools | Search this Thread | Display Modes |
|
30th September 2015, 01:04 | #1 | Link |
Registered User
Join Date: Sep 2007
Posts: 5,340
|
Help me debug this imagesource? or display configuration issue?
I get a different preview when loading this PNG image in avspmod, or vdub, or mpchc - when using ImageSource() vs. CoronaSequence(), or FFVideoSource(). The latter two have higher contrast (I think this is what it should be and appears like this in other programs like Adobe photoshop, Adobe AE, xnview, ffplay)
This appears to be a "normal" 8bit RGB PNG. There is no metadata or embedded color profile that Adobe or XNview reports. Set's Avisynth 2.6MT x86 , but also occurs in "vanilla" Avisynth 2.6 x86 Info() with CoronaSequence reads RGB32, but it's just a dummy alpha. Info with ImageSource() reads RGB24(). It doesn't matter if I ConvertToRGB24 or 32 as expected. I have included 3 images in the zip file , "hcw_mmtest_close.0000.png" is the source , and what I get taking a screenshot from avspmod with imagesource() and coronasequence() 3.52MB http://www.mediafire.com/?btucr97gil959t1 or http://www70.zippyshare.com/v/swLmlDBS/file.html Is this an ImageSource() issue, or some other local configuration issue ? Thanks |
30th September 2015, 01:10 | #2 | Link |
Registered User
Join Date: Sep 2007
Posts: 5,340
|
Actually exiftool reports a gamma of 1 in the source image - this might be the difference . In firefox for windows, the image appears like imagesource (less contrast) too , but in image editors like photoshop, irfanview, etc.. it appears like coronasequence
Does anyone know of a "jpegsnoop" -like program for PNG ? EDIT: TweakPNG - it also reports a gamma of 1.0 Summary - it appears different applications handle the gAMA chunk in PNG differently . If you strip it with TweakPNG, then it will give the higher contrast version in all (most) applications . So it appears there is a difference between imagesource() and coronasequence() handling of PNG images, when there is a gamma specified references: http://www.libpng.org/pub/png/book/c...png.ch10.div.2 https://hsivonen.fi/png-gamma/ http://jonathannicol.com/blog/2006/1...ing-png-gamma/ Last edited by poisondeathray; 30th September 2015 at 01:37. |
Thread Tools | Search this Thread |
Display Modes | |
|
|