DELTAC

Section: Local Commands (L)
Updated: 7 June 1990
Index Return to Main Contents
 

NAME

deltac, deltau - compress and expand using delta modulation  

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)


 

Index

NAME
SYNOPSIS
DESCRIPTION
DIAGNOSTICS
AUTHOR
SEE ALSO

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