Exiftool and endianness questions

Discussion in 'Apple' started by JF Mezei, Apr 30, 2014.

  1. JF Mezei

    JF Mezei Guest

    Quick questions :

    Playing with exiftool to learn.

    I noticed that iPhone photos are stored as .jpegs in big endian format.
    And so are Nikon .NEF images

    I know that big endian tiff and others was de-facto standard (despite
    TIFF supporting both) because the Macintosh was big endian and it was
    THE machine for image processing in the early days.

    I had expected that little endian would have become de facto standard by
    now, with basically all desktops being little endian. In fact, I have
    been scanning my slides little endian to tiff.

    Since the iPhone/IOS are little endian, I was surprised to see it
    generate big endian .jpegs since that would involve a lot of byte swas
    which consumed more CPU/battery.

    I have been scanning slides little endian, thinking it was the new de
    facto standard.Is it better to keep those .TIFFs big endian for
    consistency with rest of industry (even though both are supported) ?

    Secondly, on a totally different tangent:
    Image date-time (Created date) appears to be the local time, and the
    optional GMT offset which can be specified appears to be just a
    convenience. (not present in iPhone photos, but preset in my Nikon DSLR)

    Because scanned slides do not have a real date of the shot, I have to
    manually set those (I know the dates, but not the times). For pictures
    in south pacific/asia, I want to make sure that specifying a date of
    mar-7-1995 with GMT offset of +10 will always show up as Mar-7th and not
    march 6th.

    Is there a recommended time to provide when you don't have the time of
    image ? noon (12:00) or midnight (00:00) ?
    JF Mezei, Apr 30, 2014
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