121 lines
2.6 KiB
C
121 lines
2.6 KiB
C
/*
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* zyxel.c
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*
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* Converts the ZyXEL 1496 2, 3 and 4 bit voice format to the pvf format
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* and the other way around. The conversion algorithm is based on the
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* ZyXEL vcnvt program.
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*
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* The ZyXEL 2864 and the ISDN4Linux driver can also store voice data in
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* this format.
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*
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* $Id: zyxel.c,v 1.4 1998/09/09 21:07:06 gert Exp $
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*
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*/
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#include "../include/voice.h"
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static int Mx[3][8] =
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{
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{0x3800, 0x5600, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000},
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{0x399a, 0x3a9f, 0x4d14, 0x6607, 0x0000, 0x0000, 0x0000, 0x0000},
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{0x3556, 0x3556, 0x399A, 0x3A9F, 0x4200, 0x4D14, 0x6607, 0x6607}
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};
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int zyxeltopvf (FILE *fd_in, FILE *fd_out, int nbits, pvf_header *header_out)
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{
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state_t s;
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int a = 0;
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int d = 5;
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int sign;
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int e;
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if (nbits == 30)
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nbits = 3;
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if ((nbits != 2) && (nbits != 3) && (nbits != 4))
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return(FAIL);
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s = init_state;
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while ((e = read_bits(fd_in, &s, nbits)) != EOF)
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{
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if ((nbits == 4) && (e == 0))
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d = 4;
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sign = (e >> (nbits - 1)) ? (-1) : (1);
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e = e & bitmask[nbits - 1];
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a = (a * 4093 + 2048) >> 12;
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a += sign * ((e << 1) + 1) * d >> 1;
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if (d & 1)
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a++;
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header_out->write_pvf_data(fd_out, a << 10);
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d = (d * Mx[nbits - 2][e] + 0x2000) >> 14;
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if (d < 5)
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d = 5;
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};
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return(OK);
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}
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int pvftozyxel (FILE *fd_in, FILE *fd_out, int nbits, pvf_header *header_in)
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{
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int a = 0;
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int d = 5;
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state_t s;
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int e;
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int nmax;
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int sign;
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int delta;
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int data_new;
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s = init_state;
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while (!feof(fd_in))
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{
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data_new = header_in->read_pvf_data(fd_in);
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e = 0;
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nmax = 1 << (nbits - 1);
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delta = (data_new >> 10) - a;
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if (delta < 0)
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{
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e = nmax;
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delta = -delta;
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};
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while((--nmax) && (delta > d))
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{
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delta -= d;
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e++;
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};
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if ((nbits == 4) && ((e & 0x0f) == 0))
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e = 0x08;
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write_bits(fd_out, &s, nbits, e);
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a = (a * 4093 + 2048) >> 12;
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sign = (e >> (nbits - 1)) ? (-1) : (1);
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e = e & bitmask[nbits - 1];
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a += sign * ((e << 1) + 1) * d >> 1;
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if (d & 1)
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a++;
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d = (d * Mx[nbits - 2][e] + 0x2000) >> 14;
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if (d < 5)
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d = 5;
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};
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if (s.nleft > 0)
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write_bits(fd_out, &s, 8 - s.nleft, 0x00);
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return(OK);
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}
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