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 sin-
gle strip of data. The generated 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, ``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 doc-
ument. 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 resolution 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-dimen-
sional version of the CCITT Group 3 Huffman encod-
ing 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 resul-
tant 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 horizontal position is given. The remain-
der 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'' orienta-
tion; it should be possible to override this assumption
from the command line.
SEE ALSO
CCITT Recommendation T.4(Standardization of Group 3 Fac-
simile 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).