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Title: EXIF info in PNG: incorrectly written as zTXt instead of eTXt?
Post by: chemi on April 23, 2014, 01:52:07 PM

Hi,
According to http://www.exiftool.org/TagNames/PNG.html:
"By default ExifTool writes new string-value tags as as uncompressed tEXt, or compressed zTXt if the Compress (-z) option is used and Compress::Zlib is available."
However, I've tried (exiftool 9.58) and it's written by default as zTXt instead of eTXt:

"exiftool(-k).exe" -UserComment="hello" foo.png

and what is added:
...zTXtRaw profile type APP1..xœeN[.Ã .ûç.=B^.8.ëcª4mSïÿ±.mE;#p0‰±{Îïy[Çá»}–õ5»¡.ƒ:ñ!jR.ƒL2.P††hÛ.b®Ü€.$›þèu×Ø. •Aî.¨V,,|Ó«Y.šŠãÝèH±Câ-A.÷©Õáhf`rÌ..kÃù`7*..Eíô©Q.ó¿.:; ·ŸÎø‹á'.=.K'=ŠFõ:Ú².÷..pNÀ¹.P.....IEND®B`,

Am I missing something?
Any way to add it as tEXt?
Thanks.

Title: Re: EXIF info in PNG: incorrectly written as zTXt instead of eTXt?
Post by: chemi on April 23, 2014, 01:54:03 PM

>>>> eTXt
Sorry: tEXt

Title: Re: EXIF info in PNG: incorrectly written as zTXt instead of eTXt?
Post by: chemi on April 23, 2014, 01:56:10 PM

I've just noticed a raw profile is added, so this applies?:
"Raw profile information is always created as compressed zTXt if Compress::Zlib is available, or tEXt otherwise."

Title: Re: EXIF info in PNG: incorrectly written as zTXt instead of eTXt?
Post by: chemi on April 23, 2014, 02:04:55 PM

So the question would be:
Any way to add it as tEXt?

Title: Re: EXIF info in PNG: incorrectly written as zTXt instead of eTXt?
Post by: Phil Harvey on April 23, 2014, 02:15:05 PM

No. Currently PNG Raw profiles are always compressed if possible.

I think you probably don't want to be adding EXIF:UserComment to your PNG image. I would suggest instead PNG:Comment or some XMP tag.

- Phil

ExifTool Forum

ExifTool => The "exiftool" Application => Topic started by: chemi on April 23, 2014, 01:52:07 PM