AF_gain_table_u(3) AF_gain_table_u(3) NAME AF_gain_table_u, AF_gain_table_a - ULAW and ALAW gain tables SYNTAX #include <AF/AFUtils.h> extern int AF_gain_min_u, AF_gain_max_u; extern unsigned char *AF_gain_table_u[]; extern int AF_gain_min_a, AF_gain_max_a; extern unsigned char *AF_gain_table_a[]; DESCRIPTION AF_gain_table_u is an array of precomputed gain tables for ULAW samples. AF_gain_table_a is the same thing, but for ALAW samples. These tables are useful for effectivly decompressing a sample, multiplying by a constant, and recompressing. The tables are available in 1 dB steps from AF_gain_min_u to AF_gain_max_u for ULAW samples. (or from AF_gain_min_a to AF_gain_max_a for ALAW samples.) EXAMPLES Typical usage is: unsigned char *gain_table; unsigned char input, output; /* first select a particular table, for 5 dB gain */ gain_table = AF_gain_table_u[ 5 - AF_gain_min_u ]; /* now translate the sample */ output = gain_table[ input ]; 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(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