Re: CALL for DISCUSSION: eXIf 20170115
John Bowler <[email protected]>
| Newsgroups | gmane.comp.graphics.png.general |
|---|---|
| Message-ID | <CAP7U3984pUReJgPZxfgyTnTm24YMA9ta3k1+siFp5wA35PbhDA@mail.gmail.com> |
On Wed, Jan 25, 2017 at 5:58 AM, Max Stepin <[email protected]> wrote: > I think EXIF data is not big enough, so we probably shouldn't bother with > compression. Most of the space would be taken by JPEG thumbnail, anyway. > Other tags are more compressible, but saving 2kb-10kb hardly matters in the > context of storing photographs in PNG format. Even JPEGs are pretty big > these days. If the original image has been converted to PNG then this is almost certainly for editing purposes and the thumbnail will either be eliminated or rewritten. In the dumps of EXIF I looked at the MakerNote was often as big or bigger than the thumbnail. For example, from my selection of images plus Willem's generated image: Alaska.jpg: Thumbnail 7092 Alaska.jpg: MakerNote 9448 Barcelona.jpg: Thumbnail 5200 Barcelona.jpg: MakerNote 1440 BigelowLakes.jpg: Thumbnail 5344 BigelowLakes.jpg: MakerNote 2266 CollipriestHouse.jpg: Thumbnail 4265 CollipriestHouse.jpg: MakerNote 298 coral.jpg: Thumbnail 7539 coral.jpg: MakerNote 3792 dogslife.jpg: Thumbnail 7407 dogslife.jpg: MakerNote 192 exif2c08.jpg: Thumbnail 663 Lisbon.jpg: Thumbnail 4768 Lisbon.jpg: MakerNote 3058 Pharaoh.jpg: Thumbnail 7584 ruffled.jpg: Thumbnail 10170 ruffled.jpg: MakerNote 25717 The last one is the Sony/Hasselblad image. The MakerNote is manufacturer specific and maybe not even decodable. -- John Bowler <[email protected]> +1 (541) 450-9885 PO BOX 3151 KERBY OR 97531-3151 USA ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot