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Defines | |
#define | AST_LIN2MU(a) (__ast_lin2mu[((unsigned short)(a)) >> 2]) |
#define | AST_MULAW(a) (__ast_mulaw[(a)]) |
Functions | |
void | ast_ulaw_init (void) |
Init the ulaw conversion stuff. | |
Variables | |
unsigned char | __ast_lin2mu [16384] |
converts signed linear to mulaw | |
short | __ast_mulaw [256] |
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Definition at line 32 of file ulaw.h. Referenced by ast_dsp_process(). |
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Init the ulaw conversion stuff. To init the ulaw to slinear conversion stuff, this needs to be run. Definition at line 64 of file ulaw.c. References __ast_mulaw. Referenced by main().
00069 { 00070 short mu,e,f,y; 00071 static short etab[]={0,132,396,924,1980,4092,8316,16764}; 00072 00073 mu = 255-i; 00074 e = (mu & 0x70)/16; 00075 f = mu & 0x0f; 00076 y = f * (1 << (e + 3)); 00077 y += etab[e]; 00078 if (mu & 0x80) y = -y; 00079 __ast_mulaw[i] = y; 00080 } 00081 /* set up the reverse (mu-law) conversion table */ 00082 for(i = -32768; i < 32768; i++) 00083 { 00084 __ast_lin2mu[((unsigned short)i) >> 2] = linear2ulaw(i); 00085 } 00086 00087 } 00088 00089 |
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converts signed linear to mulaw
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Definition at line 29 of file ulaw.h. Referenced by ast_ulaw_init(). |