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  widely
     used 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 "AP12" markers as text. Some digital cameras
     produce AP12 markers that contain useful  textual  informa-
     tion.  You  can also modify the source code to display other
     APn marker types.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



SunOS 5.11          Last change: 26 Mar 2004                    1






User Commands                                         rdjpgcom(1)



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Availability                 SUNWjpg                     
    
     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