Re: EXIF support in PNG [was: Modern compressor]

-rw-rw-r-- 1 glennrp glennrp 53679 Dec 31 17:45 51.exif
-rw-rw-r-- 1 glennrp glennrp 27936 Dec 31 17:45 51.exif.gz
-rw-rw-r-- 1 glennrp glennrp 31355 Dec 31 17:43 51.png.0005.zTXt

I wouldn't give up compression.  For the EXIF out of my
camera, an ImageMagick zTXt/EXIF chunk is half the size
of the uncompressed EXIF.  Because of the hex expansion
followed by zlib compression it doesn't do as well as zlib
by itself.

To extract the EXIF profile out of either a JPG or a PNG,
simply run "magick file.jpg file.exif" or "magick file.png file.exif".

Glenn


On Sat, Dec 31, 2016 at 5:32 PM, Willem van Schaik <[email protected]>
wrote:

>
> At this moment I think I'm aligning with John Bowler, therefore no
> keyword, no compression. KISS
>
> Problem is of course what to do with that thumbnail that can be either
> JPEG or two types of TIFF. For us a PNG thumbnail would of course make
> most sense, but that will likely break a lot of standardization.
>
> Willem
>
>
> PS. the 2.31 standard doc (july 2016) is here:
>
> http://www.cipa.jp/std/documents/e/DC-008-Translation-2016-E.pdf
>
>
>
> On 2016-12-31 14:14, Glenn Randers-Pehrson wrote:
> >
> >
> >
> > The format of a proposed eXIf chunk would be similar to that of iCCP:
> >
> >      keyword (e.g., "Nikon EXIF data", 1-79 bytes of Latin-1 characters)
> >      null separator
> >      compression method (0 means zlib/deflate)
> >      compressed data
> >
> > Glenn
> >
>
>
> --
>
> Willem van Schaik
> <[email protected]>
> http://www.schaik.com/
>
>
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