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fax2tiff

FAX2TIFF(1)                                                        FAX2TIFF(1)



NAME
       fax2tiff - create a TIFF Class F fax file from raw fax data

SYNOPSIS
       fax2tiff [ options ] [ -o output.tif ] input.g3

DESCRIPTION
       Fax2tiff  creates  a  TIFF  file  containing  CCITT  Group 3 or Group 4
       encoded data from one or more files containing ``raw'' Group 3  encoded
       data  (typically obtained directly from a fax modem).  By default, each
       row of data in the resultant TIFF file is 2-dimensionally  encoded  and
       padded  or truncated to 1728 pixels, as needed.  The resultant image is
       a set of low resolution  (98  lines/inch)  or  medium  resolution  (196
       lines/inch) pages, each of which is a single strip of data.  The gener-
       ated file conforms to the TIFF Class F (FAX) specification for  storing
       facsimile  data.  This means, in particular, that each page of the data
       does not include the trailing return to control (RTC) code; as required
       for transmission by the CCITT Group 3 specifications.  The old, ``clas-
       sic'', format is created if the -c option is used.  (The Class F format
       can also be requested with the -f option.)

       The  default  name  of the output image is fax.tif; this can be changed
       with the -o option.  Each input file is assumed to be a  separate  page
       of  facsimile  data  from  the same document.  The order in which input
       files are specified on the command line  is  the  order  in  which  the
       resultant pages appear in the output file.

OPTIONS
       Options that affect the interpretation of input data are:

       -2     Assume input data is 2-d Huffman encoded.

       -B     Assume input data was encoded with black as 0 and white as 1.

       -L     Treat  input  data  as having bits filled from least significant
              bit (LSB) to most significant bit (MSB).  (This is the default.)

       -M     Treat input data as having bits filled from most significant bit
              (MSB) to most least bit (LSB).

       -R     Specify the vertical resolution, in  lines/inch,  of  the  input
              images.  By default input are assumed to have a vertical resolu-
              tion of 196 lines/inch.  If images are low resolution facsimile,
              a value of 98 lines/inch should be specified.

       -W     Assume  input  data  was encoded with black as 1 and white as 0.
              (This is the default.)

       Options that affect the output file format are:

       -1     Force output to be compressed with the 1-dimensional version  of
              the CCITT Group 3 Huffman encoding algorithm.

       -4     Force  output  to  be  compressed with the CCITT Group 4 Huffman
              encoding.

       -o     Specify the name of the output file.

       -p     Force the last bit of each End Of Line (EOL) code to land  on  a
              byte  boundary.   This ``zero padding'' will be reflected in the
              contents of the Group3Options tag of the resultant TIFF file.

       -s     Stretch the input image vertically by writing each input row  of
              data twice to the output file.

       -v     Force  fax2tiff to print the number of rows of data it retrieved
              from the input file.

DIAGNOSTICS
       The following warnings and errors come from the  decoding  routines  in
       the library.

       Warning,  %s:  Premature  EOL at scanline %d (x %d).\n.  The input data
       had a row that was shorter than the expected value of 1728.  The row is
       padded with white.

       %s:  Premature  EOF  at  scanline %d (x %d).\n.  The decoder ran out of
       data in the middle of a scanline.  The resultant  row  is  padded  with
       white.

       %s:  Bad  code  word  at  row  %d, x %d\n.  An invalid Group 3 code was
       encountered while decoding the input file.  The row number and horizon-
       tal  position  is  given.  The remainder of the input row is discarded,
       while the corresponding output row is padded with white.

       %s: Bad 2D code word at scanline %d.\n.  An invalid Group 4 or 2D Group
       3  code  was encountered while decoding the input file.  The row number
       and horizontal position is given.  The remainder of the  input  row  is
       discarded, while the corresponding output row is padded with white.

BUGS
       Should  not have the constant width 1728 built into it.  Input data are
       assumed to have a a ``top left'' orientation; it should be possible  to
       override this assumption from the command line.

SEE ALSO
       CCITT  Recommendation T.4 (Standardization of Group 3 Facsimile Appara-
       tus for Document Transmission).

       The Spirit of TIFF Class F, an appendix to the TIFF  5.0  specification
       prepared by Cygnet Technologies.

       tiffinfo(1), tiffdither(1), tiffgt(1), libtiff(3).



                              September 24, 1994                   FAX2TIFF(1)