FAX2TIFF(1)               UNIX System V(May 18, 1991)               FAX2TIFF(1)


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

SYNOPSIS
      fax2tiff [ -1 ] [ -2 ] [ -4 ] [ -c ] [ -f ] [ -k ] [ -l ] [ -o tiff-file
      ] [ -p ] [ -r ] [ -s ] [ -v ] [ -w ] [ -O ] fax-files

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).  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 series of low resolution
      (98 lines/inch) or medium resolution (196 lines/inch) pages, each of
      which is a single strip of data.  By default, the image conforms to the
      proposed 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, ``classic'', 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.

      By default, the output file is compressed with the 2-dimensional version
      of the CCITT Group 3 Huffman encoding algorithm.  If the -1 option is
      specified, 1-dimensional Huffman encoding will be used.  If the -4 option
      is specified, CCITT Group 4 Huffman encoding will be used.

      By default, the output file is created with bits filled from least
      significant bit (LSB) to most significant bit (MSB).  This fill order can
      be reversed with the -O option.  Fax2tiff expects that the bit ordering
      of data in the input file is likewise set from LSB to MSB. If the reverse
      is true, the -r flag should be specified.

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

      By default, fax2tiff assumes that alll input files contain 1-
      dimensionally encoded Group 3 data.  If the -2 option is specified,
      fax2tiff will assume the input files contain 2-dimensionally encoded
      Group 3 data.

      The input data are assumed to have a vertical resolution of 196
      lines/inch.  If the images are low resolution facsimile (98 lines/inch),
      the -l flag should be specified.


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FAX2TIFF(1)               UNIX System V(May 18, 1991)               FAX2TIFF(1)


      By default, fax2tiff prints only diagnostics about badly formed input
      rows.  If the -w flag is supplied, additional warning information will be
      printed about input data rows that are longer or shorter than 1728
      pixels.

      If the -v option is specified, fax2tiff will print the number of rows of
      data it retrieved from the input file.  If this option is given twice,
      voluminous information about the length of each encoded run in the input
      file will be printed.

      Some fax files have garbage information at their front.  The -k flag
      causes fax2tiff to skip three rows of input data before starting to its
      normal operation.  (It should skip rows until a row with a just an EOL is
      encountered.)

      For viewing, a one-to-one row conversion of fax data results in an image
      that appears squashed.  If the -s flag is supplied, fax2tiff will
      ``stretch'' the image vertically by writing each row of input data twice
      in the output file.

DIAGNOSTICS
      %s: Warning, row %d short (len %d).\n.  The input data had a row that was
      shorter than the expected value of 1728.  The row is padded with white.

      %s: Bad code word at row %d, x %d (len %d code 0x%x), skipping to EOL\n.
      An invalid Group 3 code was encountered while decoding the input file.
      The length of the code (in bits) and its value is displayed.  The row
      number and horizontal position is also given.  The remainder of the input
      row is discarded, while the corresponding output row is padded with
      white.

      Some internal errors that should never happen.

NOTES
      This program is derived from a similar program by Paul Haeberli and uses
      code written by Jef Poskanzer.

BUGS
      Should synchronize finding the top of the input file by looking for a row
      with just an EOL . 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 Apparatus
      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).






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