User Commands rdjpgcom(1)
NAME
rdjpgcom - display text comments from a JPEG file
SYNOPSIS
rdjpgcom [-verbose] [filename]
DESCRIPTION
rdjpgcom reads the named JPEG or JFIF file, or the standard
input if no file is named, and displays any text comments found in the file on the standard output. The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file. Although the standard does not actually define the intended function of COM blocks, they are widelyused to hold user-supplied text strings. This enables you to
add annotations, titles, index terms, and so on to your JPEG files, and later retrieve the COM blocks as text. COM blocks do not interfere with the image stored in the JPEG file. The maximum size of a COM block is 64K, but you can have many COM blocks in one JPEG file. OPTIONS The following options are supported:-verbose Causes rdjpgcom to also display the JPEG
image dimensions. OPERANDS The following operands are supported: filename The name of the JPEG file that contains text comments.EXTENDED DESCRIPTION
rdjpgcom does not depend on the IJG JPEG library. The
rdjpgcom source code is intended to illustrate the minimum
amount of code required to parse a JPEG file header correctly.In -verbose mode, rdjpgcom also attempts to display the con-
tents of any "APP12" markers as text. Some digital camerasproduce APP12 markers that contain useful textual informa-
tion. You can also modify the source code to display other APPn marker types.ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:SunOS 5.11 Last change: 26 Mar 2004 1
User Commands rdjpgcom(1)
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | image/library/libjpeg ||_____________________________|_____________________________|
| Interface stability | Volatile ||_____________________________|_____________________________|
SEE ALSO
cjpeg(1), djpeg(1), jpegtran(1), wrjpgcom(1) NOTES This man page was originally written by the Independent JPEG Group. Updated by Breda McColgan, Sun Microsystems Inc., 2004.SunOS 5.11 Last change: 26 Mar 2004 2