AF_exp_u(3) AF_exp_u(3) NAME AF_exp_u, AF_exp_a - ULAW and ALAW decompression tables SYNTAX #include <AF/AFUtils.h> extern short int AF_exp_u[]; extern short int AF_exp_a[]; extern short int AF_cvt_u2s[]; extern short int AF_cvt_a2s[]; extern float AF_cvt_u2f[]; extern float AF_cvt_a2f[]; DESCRIPTION These are preexputed tables you can link with your application. AF_exp_u is indexed by a ULAW sample and AF_exp_a is indexed by an ALAW sample. Each contains a 16 bit signed integer value representing the corresponding linear value. Table entries are in the range between -8192 and +8191. AF_cvt_u2s and AF_cvt_a2s are indexed by ULAW and ALAW samples respectively and contain 16 bit signed linear values scaled to the range between -32767 and +32767. AF_cvt_u2f and AF_cvt_a2f are indexed by ULAW and ALAW samples respectively and contain single precision floating point linear values scaled to the range between -1.0 and +1.0. EXAMPLES Typical usage is: unsigned char ulaw; short int lin13; short int lin16; short int linfloat; lin13 = AF_exp_u[ ulaw ]; lin16 = AF_cvt_u2s[ ulaw ]; linflat = AF_cvt_u2f[ ulaw ]; DIAGNOSTICS If you index a table with an out-of-range value you may cause a protection fault and crash your application. SEE ALSO AF_comp_u(3), AF_comp_a(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