AF_comp_u(3)

NAME
AF_comp_u, AF_comp_a - linear to ULAW and ALAW compression tables

SYNTAX
#include <AF/AFUtils.h>

extern unsigned char AF_comp_u[];

extern unsigned char AF_comp_a[];

DESCRIPTION
and are precomputed tables you can link with your application. Each is indexed by the low 14 bits of a linear twos-complement value in the range between -8192 and +8191. contains the corresponding U255 law encoding while contains the corresponding ALAW encoding.

EXAMPLES
Typical usage is:

unsigned char ulaw; int input; /* first limit the signal to the proper range */ if (input > 8191) input = 8191; else if (input < -8181) input = -8191; /* then translate */ ulaw = AF_comp_u[ input & 0x3fff ];

DIAGNOSTICS
If you index the table with an out-of-range linear value you may cause a protection fault and crash your application.

SEE ALSO
AF_exp_u(3), AF_exp_a(3), AF_cvt_u2s(3), AF_cvt_a2s(3), AF_cvt_u2f(3), AF_cvt_a2f(3)
AF(1)

BUGS
If you encounter a reproducible bug, please submit a problem report to (af-bugs@crl.dec.com).

COPYRIGHT
Copyright 1990-1994, Digital Equipment Corporation.
See AF(1) for a full statement of rights and permissions.

AUTHORS
Tom Levergood and Larry Stewart, Digital Cambridge Research Lab