Re: CALL for DISCUSSION: eXIf 20170115 -- length
Willem van Schaik <[email protected]>
| Newsgroups | gmane.comp.graphics.png.general |
|---|---|
| Message-ID | <[email protected]> |
That EOI marker, simply helped me a lot debugging my EXIF profiles in JPEG files. On purpose I didn't say "it ends" but included that "often". In the pictures I analyzed (from different cameras) it is there. Willem On 2017-01-16 23:37, John Bowler wrote: > On Mon, Jan 16, 2017 at 10:04 PM, Willem van Schaik <[email protected]> wrote: >> and maybe we should add: >> >> It will often end with 0xFFD9 (there could be a padding byte >> 0x00) which is the EXIF EOI (End of Image) marker, because >> many EXIF profiles end with a thumbnail image. > > So far as I know there is no reason for the thumbnail to be at the end > even though the CIPA document shows it there and there is no reason > for the thumbnail to be a JPEG stream. Indeed if the main image is > uncompressed the thumbnail cannot be compressed while if the main > image is compressed an uncompressed thumbnail may be used. > > See the discussion on page 24 of CIPA 2016. > -- Willem van Schaik [email protected] ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot