g722_decode.c

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/*
 * SpanDSP - a series of DSP components for telephony
 *
 * g722_decode.c - The ITU G.722 codec, decode part.
 *
 * Written by Steve Underwood <[email protected]>
 *
 * Copyright (C) 2005 Steve Underwood
 *
 * Despite my general liking of the GPL, I place my own contributions
 * to this code in the public domain for the benefit of all mankind -
 * even the slimy ones who might try to proprietize my work and use it
 * to my detriment.
 *
 * Based in part on a single channel G.722 codec which is:
 *
 * Copyright (c) CMU 1993
 * Computer Science, Speech Group
 * Chengxiang Lu and Alex Hauptmann
 *
 * $Id$
 */

/*! \file */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <inttypes.h>
#include <memory.h>
#include <stdlib.h>
#if 0
#include <tgmath.h>
#endif

#include "g722.h"

#if !defined(FALSE)
#define FALSE 0
#endif
#if !defined(TRUE)
#define TRUE (!FALSE)
#endif

static __inline__ int16_t saturate(int32_t amp)
{
 int16_t amp16;

 /* Hopefully this is optimised for the common case - not clipping */
 amp16 = (int16_t) amp;
 if (amp == amp16)
 return amp16;
 if (amp > INT16_MAX)
 return INT16_MAX;
 return INT16_MIN;
}
/*- End of function --------------------------------------------------------*/

static void block4(g722_decode_state_t *s, int band, int d);

static void block4(g722_decode_state_t *s, int band, int d)
{
 int wd1;
 int wd2;
 int wd3;
 int i;

 /* Block 4, RECONS */
 s->band[band].d[0] = d;
 s->band[band].r[0] = saturate(s->band[band].s + d);

 /* Block 4, PARREC */
 s->band[band].p[0] = saturate(s->band[band].sz + d);

 /* Block 4, UPPOL2 */
 for (i = 0; i < 3; i++)
 s->band[band].sg[i] = s->band[band].p[i] >> 15;
 wd1 = saturate(s->band[band].a[1] << 2);

 wd2 = (s->band[band].sg[0] == s->band[band].sg[1]) ? -wd1 : wd1;
 if (wd2 > 32767)
 wd2 = 32767;
 wd3 = (s->band[band].sg[0] == s->band[band].sg[2]) ? 128 : -128;
 wd3 += (wd2 >> 7);
 wd3 += (s->band[band].a[2]*32512) >> 15;
 if (wd3 > 12288)
 wd3 = 12288;
 else if (wd3 < -12288)
 wd3 = -12288;
 s->band[band].ap[2] = wd3;

 /* Block 4, UPPOL1 */
 s->band[band].sg[0] = s->band[band].p[0] >> 15;
 s->band[band].sg[1] = s->band[band].p[1] >> 15;
 wd1 = (s->band[band].sg[0] == s->band[band].sg[1]) ? 192 : -192;
 wd2 = (s->band[band].a[1]*32640) >> 15;

 s->band[band].ap[1] = saturate(wd1 + wd2);
 wd3 = saturate(15360 - s->band[band].ap[2]);
 if (s->band[band].ap[1] > wd3)
 s->band[band].ap[1] = wd3;
 else if (s->band[band].ap[1] < -wd3)
 s->band[band].ap[1] = -wd3;

 /* Block 4, UPZERO */
 wd1 = (d == 0) ? 0 : 128;
 s->band[band].sg[0] = d >> 15;
 for (i = 1; i < 7; i++)
 {
 s->band[band].sg[i] = s->band[band].d[i] >> 15;
 wd2 = (s->band[band].sg[i] == s->band[band].sg[0]) ? wd1 : -wd1;
 wd3 = (s->band[band].b[i]*32640) >> 15;
 s->band[band].bp[i] = saturate(wd2 + wd3);
 }

 /* Block 4, DELAYA */
 for (i = 6; i > 0; i--)
 {
 s->band[band].d[i] = s->band[band].d[i - 1];
 s->band[band].b[i] = s->band[band].bp[i];
 }

 for (i = 2; i > 0; i--)
 {
 s->band[band].r[i] = s->band[band].r[i - 1];
 s->band[band].p[i] = s->band[band].p[i - 1];
 s->band[band].a[i] = s->band[band].ap[i];
 }

 /* Block 4, FILTEP */
 wd1 = saturate(s->band[band].r[1] + s->band[band].r[1]);
 wd1 = (s->band[band].a[1]*wd1) >> 15;
 wd2 = saturate(s->band[band].r[2] + s->band[band].r[2]);
 wd2 = (s->band[band].a[2]*wd2) >> 15;
 s->band[band].sp = saturate(wd1 + wd2);

 /* Block 4, FILTEZ */
 s->band[band].sz = 0;
 for (i = 6; i > 0; i--)
 {
 wd1 = saturate(s->band[band].d[i] + s->band[band].d[i]);
 s->band[band].sz += (s->band[band].b[i]*wd1) >> 15;
 }
 s->band[band].sz = saturate(s->band[band].sz);

 /* Block 4, PREDIC */
 s->band[band].s = saturate(s->band[band].sp + s->band[band].sz);
}
/*- End of function --------------------------------------------------------*/

g722_decode_state_t *g722_decode_init(g722_decode_state_t *s, int rate, int options)
{
 if (s == NULL)
 {
 if ((s = (g722_decode_state_t *) malloc(sizeof(*s))) == NULL)
 return NULL;
 }
 memset(s, 0, sizeof(*s));
 if (rate == 48000)
 s->bits_per_sample = 6;
 else if (rate == 56000)
 s->bits_per_sample = 7;
 else
 s->bits_per_sample = 8;
 if ((options & G722_SAMPLE_RATE_8000))
 s->eight_k = TRUE;
 if ((options & G722_PACKED) && s->bits_per_sample != 8)
 s->packed = TRUE;
 else
 s->packed = FALSE;
 s->band[0].det = 32;
 s->band[1].det = 8;
 return s;
}
/*- End of function --------------------------------------------------------*/

int g722_decode_release(g722_decode_state_t *s)
{
 free(s);
 return 0;
}
/*- End of function --------------------------------------------------------*/

int g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len)
{
 static const int wl[8] = {-60, -30, 58, 172, 334, 538, 1198, 3042 };
 static const int rl42[16] = {0, 7, 6, 5, 4, 3, 2, 1, 7, 6, 5, 4, 3, 2, 1, 0 };
 static const int ilb[32] =
 {
 2048, 2093, 2139, 2186, 2233, 2282, 2332,
 2383, 2435, 2489, 2543, 2599, 2656, 2714,
 2774, 2834, 2896, 2960, 3025, 3091, 3158,
 3228, 3298, 3371, 3444, 3520, 3597, 3676,
 3756, 3838, 3922, 4008
 };
 static const int wh[3] = {0, -214, 798};
 static const int rh2[4] = {2, 1, 2, 1};
 static const int qm2[4] = {-7408, -1616, 7408, 1616};
 static const int qm4[16] =
 {
 0, -20456, -12896, -8968,
 -6288, -4240, -2584, -1200,
 20456, 12896, 8968, 6288,
 4240, 2584, 1200, 0
 };
 static const int qm5[32] =
 {
 -280, -280, -23352, -17560,
 -14120, -11664, -9752, -8184,
 -6864, -5712, -4696, -3784,
 -2960, -2208, -1520, -880,
 23352, 17560, 14120, 11664,
 9752, 8184, 6864, 5712,
 4696, 3784, 2960, 2208,
 1520, 880, 280, -280
 };
 static const int qm6[64] =
 {
 -136, -136, -136, -136,
 -24808, -21904, -19008, -16704,
 -14984, -13512, -12280, -11192,
 -10232, -9360, -8576, -7856,
 -7192, -6576, -6000, -5456,
 -4944, -4464, -4008, -3576,
 -3168, -2776, -2400, -2032,
 -1688, -1360, -1040, -728,
 24808, 21904, 19008, 16704,
 14984, 13512, 12280, 11192,
 10232, 9360, 8576, 7856,
 7192, 6576, 6000, 5456,
 4944, 4464, 4008, 3576,
 3168, 2776, 2400, 2032,
 1688, 1360, 1040, 728,
 432, 136, -432, -136
 };
 static const int qmf_coeffs[12] =
 {
 3, -11, 12, 32, -210, 951, 3876, -805, 362, -156, 53, -11,
 };

 int dlowt;
 int rlow;
 int ihigh;
 int dhigh;
 int rhigh;
 int xout1;
 int xout2;
 int wd1;
 int wd2;
 int wd3;
 int code;
 int outlen;
 int i;
 int j;

 outlen = 0;
 rhigh = 0;
 for (j = 0; j < len; )
 {
 if (s->packed)
 {
 /* Unpack the code bits */
 if (s->in_bits < s->bits_per_sample)
 {
 s->in_buffer |= (g722_data[j++] << s->in_bits);
 s->in_bits += 8;
 }
 code = s->in_buffer & ((1 << s->bits_per_sample) - 1);
 s->in_buffer >>= s->bits_per_sample;
 s->in_bits -= s->bits_per_sample;
 }
 else
 {
 code = g722_data[j++];
 }

 switch (s->bits_per_sample)
 {
 default:
 case 8:
 wd1 = code & 0x3F;
 ihigh = (code >> 6) & 0x03;
 wd2 = qm6[wd1];
 wd1 >>= 2;
 break;
 case 7:
 wd1 = code & 0x1F;
 ihigh = (code >> 5) & 0x03;
 wd2 = qm5[wd1];
 wd1 >>= 1;
 break;
 case 6:
 wd1 = code & 0x0F;
 ihigh = (code >> 4) & 0x03;
 wd2 = qm4[wd1];
 break;
 }
 /* Block 5L, LOW BAND INVQBL */
 wd2 = (s->band[0].det*wd2) >> 15;
 /* Block 5L, RECONS */
 rlow = s->band[0].s + wd2;
 /* Block 6L, LIMIT */
 if (rlow > 16383)
 rlow = 16383;
 else if (rlow < -16384)
 rlow = -16384;

 /* Block 2L, INVQAL */
 wd2 = qm4[wd1];
 dlowt = (s->band[0].det*wd2) >> 15;

 /* Block 3L, LOGSCL */
 wd2 = rl42[wd1];
 wd1 = (s->band[0].nb*127) >> 7;
 wd1 += wl[wd2];
 if (wd1 < 0)
 wd1 = 0;
 else if (wd1 > 18432)
 wd1 = 18432;
 s->band[0].nb = wd1;

 /* Block 3L, SCALEL */
 wd1 = (s->band[0].nb >> 6) & 31;
 wd2 = 8 - (s->band[0].nb >> 11);
 wd3 = (wd2 < 0) ? (ilb[wd1] << -wd2) : (ilb[wd1] >> wd2);
 s->band[0].det = wd3 << 2;

 block4(s, 0, dlowt);

 if (!s->eight_k)
 {
 /* Block 2H, INVQAH */
 wd2 = qm2[ihigh];
 dhigh = (s->band[1].det*wd2) >> 15;
 /* Block 5H, RECONS */
 rhigh = dhigh + s->band[1].s;
 /* Block 6H, LIMIT */
 if (rhigh > 16383)
 rhigh = 16383;
 else if (rhigh < -16384)
 rhigh = -16384;

 /* Block 2H, INVQAH */
 wd2 = rh2[ihigh];
 wd1 = (s->band[1].nb*127) >> 7;
 wd1 += wh[wd2];
 if (wd1 < 0)
 wd1 = 0;
 else if (wd1 > 22528)
 wd1 = 22528;
 s->band[1].nb = wd1;

 /* Block 3H, SCALEH */
 wd1 = (s->band[1].nb >> 6) & 31;
 wd2 = 10 - (s->band[1].nb >> 11);
 wd3 = (wd2 < 0) ? (ilb[wd1] << -wd2) : (ilb[wd1] >> wd2);
 s->band[1].det = wd3 << 2;

 block4(s, 1, dhigh);
 }

 if (s->itu_test_mode)
 {
 amp[outlen++] = (int16_t) (rlow << 1);
 amp[outlen++] = (int16_t) (rhigh << 1);
 }
 else
 {
 if (s->eight_k)
 {
 amp[outlen++] = (int16_t) (rlow << 1);
 }
 else
 {
 /* Apply the receive QMF */
 for (i = 0; i < 22; i++)
 s->x[i] = s->x[i + 2];
 s->x[22] = rlow + rhigh;
 s->x[23] = rlow - rhigh;

 xout1 = 0;
 xout2 = 0;
 for (i = 0; i < 12; i++)
 {
 xout2 += s->x[2*i]*qmf_coeffs[i];
 xout1 += s->x[2*i + 1]*qmf_coeffs[11 - i];
 }
 amp[outlen++] = (int16_t) (xout1 >> 11);
 amp[outlen++] = (int16_t) (xout2 >> 11);
 }
 }
 }
 return outlen;
}
/*- End of function --------------------------------------------------------*/
/*- End of file ------------------------------------------------------------*/