deltac

SYNOPSIS

     deltac nooptions

     deltau nooptions

DESCRIPTION

     Deltac compresses eight bit data from standard input to the
     standard output using delta modulation.  Each byte is stored
     as four bits if the absolute value of its difference from a
     running value is less than 8.  This technique has proven to
     be more effective than compress(1) or pack(1) for 8 bit grey
     level graphics images.  It could also work on 24 bit colour
     images if each plane is stored separately.  For any other
     data the size will probably increase.

     Deltau reads data compressed produced by deltac from the
     standard input and outputs the uncompressed data on standard
     output.

DIAGNOSTICS

     Both programs will terminate with an error if they fail on
     writing on standard output.

AUTHOR

     Diomidis Spinellis <dds@cc.ic.ac.uk>

SEE ALSO

     compress(1) pack(1)