Re: DRAFT: eXIf 2017-02-28
Pavel Zlatovratskii <[email protected]> Fri, 3 Mar 2017 00:17:18 +0300
| Newsgroups | gmane.comp.graphics.png.general |
|---|---|
| Organization | TB.Budget |
| Message-ID | <[email protected]> |
Ok. As supposed by CIPA main part which can lead to pass 64k limit is thumbnail preview. Important parts of EXIF header may be absent in eXIf chunk: resolution, description or copyright. So PNG-to-JPEG recoder should be able to construct new EXIF. In comparison to recompress whole image build and compress small preview supposed to be easy. Therefore for most cases PNG-to-JPEG recoder could fit EXIF into APP1 by creating thumbnail of appropriate size. (And it may be useful to have bigger thumbnail for lossless PNG in PNG-as-RAW scenarios) Only exception when it's not possible to fit APP1 due to size of eXIf is too big MakerNote. Yet CIPA does not provide any kind of recommendations to limit MakerNote size in TIFF. It seems they are sure: there is very low possibility that someone encounter such troubles ever(and I agree). May be it will be useful to write some additional appendix to PNGEXT about recoding PNG to JPEG and design metadata that's supposed to be recoded. Including "Does not put associated novel into Comment text". 02.03.2017 23:19, Glenn Randers-Pehrson пишет: > On Thu, Mar 2, 2017 at 2:33 PM, Pavel Zlatovratskii <[email protected]> wrote: > >> I see no reason to mention JPEG. If there is some - please name it. > The 64k profile size limit comes from JPEG. As far as I can tell, the > profile size is unlimited (except that the offsets are limited to 32 bits) > when contained in a TIFF. > > Glenn > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > png-mng-misc mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/png-mng-misc -- Have a nice DOS. Pavel Zlatovratskii [email protected]; [email protected] ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ png-mng-misc mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/png-mng-misc