JEITA CP-3451
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Figure 32 Procedure for Image Data Reproduction
Some off-the-shelf software lacks a function for handling valid image width and height tags. If the valid image width
differs from the number of horizontal pixels recorded in the SOF, padding data may be displayed. The padding data
values should be chosen with this possibility in mind.
4.8.2 Stipulations on Thumbnails
A. Exif writer
The recording of thumbnail images is an optional specification of the Exif reader. It is therefore allowable to have
Exif files with and without thumbnails. For details see section 4.5.5.
B. Exif reader
This format is designed so that the primary image will be reproduced intact whether or not thumbnail images are
recorded in the file. It is assumed that even when functions are provided for viewing images on the camera or
player, for viewing the process of image transfer from camera to PC, or for using thumbnails as an index display in
the camera software or other image software, there will still be cases where the file is viewed without thumbnails.
The creation and displaying of thumbnails can therefore be performed or not at the discretion of the user.
4.8.3 File Name Stipulations
A. Exif writer
The file name and characters used for file names are not specified, other than to stipulate the use of ASCII
alphanumerics. (File names in Japanese or other character sets are not to be used.) File names shall be 8
characters or fewer, not including the extension. (Long file names are not to be used.) The file name extensions are
".JPG" for compressed data files and ".TIF" for uncompressed data files.
4.8.4 Byte Order Stipulations
A. Exif Reader
It is recommended that the Exif reader be able to reproduce Exif files recorded in both little endian and big endian
formats.
PixelX/YDimension
= SOF.X,SOF.Y ?
Trimming with
PixelX/YDimension
JPEG Decompression
based on SOF.X, SOF.Y
No
Yes