Mercurial > hg > audiostuff
diff spandsp-0.0.3/spandsp-0.0.3/src/g726.c @ 5:f762bf195c4b
import spandsp-0.0.3
| author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
|---|---|
| date | Fri, 25 Jun 2010 16:00:21 +0200 |
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| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/spandsp-0.0.3/spandsp-0.0.3/src/g726.c Fri Jun 25 16:00:21 2010 +0200 @@ -0,0 +1,1178 @@ +/* + * SpanDSP - a series of DSP components for telephony + * + * g726.c - The ITU G.726 codec. + * + * Written by Steve Underwood <steveu@coppice.org> + * + * Copyright (C) 2006 Steve Underwood + * + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2, as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + * Based on G.721/G.723 code which is: + * + * This source code is a product of Sun Microsystems, Inc. and is provided + * for unrestricted use. Users may copy or modify this source code without + * charge. + * + * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING + * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR + * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. + * + * Sun source code is provided with no support and without any obligation on + * the part of Sun Microsystems, Inc. to assist in its use, correction, + * modification or enhancement. + * + * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE + * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE + * OR ANY PART THEREOF. + * + * In no event will Sun Microsystems, Inc. be liable for any lost revenue + * or profits or other special, indirect and consequential damages, even if + * Sun has been advised of the possibility of such damages. + * + * Sun Microsystems, Inc. + * 2550 Garcia Avenue + * Mountain View, California 94043 + * + * $Id: g726.c,v 1.17 2006/11/19 14:07:24 steveu Exp $ + */ + +/*! \file */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <inttypes.h> +#include <memory.h> +#include <stdlib.h> +#if defined(HAVE_TGMATH_H) +#include <tgmath.h> +#endif +#if defined(HAVE_MATH_H) +#include <math.h> +#endif + +#include "spandsp/telephony.h" +#include "spandsp/dc_restore.h" +#include "spandsp/bitstream.h" +#include "spandsp/bit_operations.h" +#include "spandsp/g711.h" +#include "spandsp/g726.h" + +/* + * Maps G.726_16 code word to reconstructed scale factor normalized log + * magnitude values. + */ +static const int g726_16_dqlntab[4] = +{ + 116, 365, 365, 116 +}; + +/* Maps G.726_16 code word to log of scale factor multiplier. */ +static const int g726_16_witab[4] = +{ + -704, 14048, 14048, -704 +}; + +/* + * Maps G.726_16 code words to a set of values whose long and short + * term averages are computed and then compared to give an indication + * how stationary (steady state) the signal is. + */ +static const int g726_16_fitab[4] = +{ + 0x000, 0xE00, 0xE00, 0x000 +}; + +static const int qtab_726_16[1] = +{ + 261 +}; + +/* + * Maps G.726_24 code word to reconstructed scale factor normalized log + * magnitude values. + */ +static const int g726_24_dqlntab[8] = +{ + -2048, 135, 273, 373, 373, 273, 135, -2048 +}; + +/* Maps G.726_24 code word to log of scale factor multiplier. */ +static const int g726_24_witab[8] = +{ + -128, 960, 4384, 18624, 18624, 4384, 960, -128 +}; + +/* + * Maps G.726_24 code words to a set of values whose long and short + * term averages are computed and then compared to give an indication + * how stationary (steady state) the signal is. + */ +static const int g726_24_fitab[8] = +{ + 0x000, 0x200, 0x400, 0xE00, 0xE00, 0x400, 0x200, 0x000 +}; + +static const int qtab_726_24[3] = +{ + 8, 218, 331 +}; + +/* + * Maps G.726_32 code word to reconstructed scale factor normalized log + * magnitude values. + */ +static const int g726_32_dqlntab[16] = +{ + -2048, 4, 135, 213, 273, 323, 373, 425, + 425, 373, 323, 273, 213, 135, 4, -2048 +}; + +/* Maps G.726_32 code word to log of scale factor multiplier. */ +static const int g726_32_witab[16] = +{ + -384, 576, 1312, 2048, 3584, 6336, 11360, 35904, + 35904, 11360, 6336, 3584, 2048, 1312, 576, -384 +}; + +/* + * Maps G.726_32 code words to a set of values whose long and short + * term averages are computed and then compared to give an indication + * how stationary (steady state) the signal is. + */ +static const int g726_32_fitab[16] = +{ + 0x000, 0x000, 0x000, 0x200, 0x200, 0x200, 0x600, 0xE00, + 0xE00, 0x600, 0x200, 0x200, 0x200, 0x000, 0x000, 0x000 +}; + +static const int qtab_726_32[7] = +{ + -124, 80, 178, 246, 300, 349, 400 +}; + +/* + * Maps G.726_40 code word to ructeconstructed scale factor normalized log + * magnitude values. + */ +static const int g726_40_dqlntab[32] = +{ + -2048, -66, 28, 104, 169, 224, 274, 318, + 358, 395, 429, 459, 488, 514, 539, 566, + 566, 539, 514, 488, 459, 429, 395, 358, + 318, 274, 224, 169, 104, 28, -66, -2048 +}; + +/* Maps G.726_40 code word to log of scale factor multiplier. */ +static const int g726_40_witab[32] = +{ + 448, 448, 768, 1248, 1280, 1312, 1856, 3200, + 4512, 5728, 7008, 8960, 11456, 14080, 16928, 22272, + 22272, 16928, 14080, 11456, 8960, 7008, 5728, 4512, + 3200, 1856, 1312, 1280, 1248, 768, 448, 448 +}; + +/* + * Maps G.726_40 code words to a set of values whose long and short + * term averages are computed and then compared to give an indication + * how stationary (steady state) the signal is. + */ +static const int g726_40_fitab[32] = +{ + 0x000, 0x000, 0x000, 0x000, 0x000, 0x200, 0x200, 0x200, + 0x200, 0x200, 0x400, 0x600, 0x800, 0xA00, 0xC00, 0xC00, + 0xC00, 0xC00, 0xA00, 0x800, 0x600, 0x400, 0x200, 0x200, + 0x200, 0x200, 0x200, 0x000, 0x000, 0x000, 0x000, 0x000 +}; + +static const int qtab_726_40[15] = +{ + -122, -16, 68, 139, 198, 250, 298, 339, + 378, 413, 445, 475, 502, 528, 553 +}; + +/* + * returns the integer product of the 14-bit integer "an" and + * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn". + */ +static int16_t fmult(int16_t an, int16_t srn) +{ + int16_t anmag; + int16_t anexp; + int16_t anmant; + int16_t wanexp; + int16_t wanmant; + int16_t retval; + + anmag = (an > 0) ? an : ((-an) & 0x1FFF); + anexp = (int16_t) (top_bit(anmag) - 5); + anmant = (anmag == 0) ? 32 : (anexp >= 0) ? (anmag >> anexp) : (anmag << -anexp); + wanexp = anexp + ((srn >> 6) & 0xF) - 13; + + wanmant = (anmant*(srn & 0x3F) + 0x30) >> 4; + retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) : (wanmant >> -wanexp); + + return (((an ^ srn) < 0) ? -retval : retval); +} +/*- End of function --------------------------------------------------------*/ + +/* + * Compute the estimated signal from the 6-zero predictor. + */ +static __inline__ int16_t predictor_zero(g726_state_t *s) +{ + int i; + int sezi; + + sezi = fmult(s->b[0] >> 2, s->dq[0]); + /* ACCUM */ + for (i = 1; i < 6; i++) + sezi += fmult(s->b[i] >> 2, s->dq[i]); + return (int16_t) sezi; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Computes the estimated signal from the 2-pole predictor. + */ +static __inline__ int16_t predictor_pole(g726_state_t *s) +{ + return (fmult(s->a[1] >> 2, s->sr[1]) + fmult(s->a[0] >> 2, s->sr[0])); +} +/*- End of function --------------------------------------------------------*/ + +/* + * Computes the quantization step size of the adaptive quantizer. + */ +static int step_size(g726_state_t *s) +{ + int y; + int dif; + int al; + + if (s->ap >= 256) + return s->yu; + y = s->yl >> 6; + dif = s->yu - y; + al = s->ap >> 2; + if (dif > 0) + y += (dif*al) >> 6; + else if (dif < 0) + y += (dif*al + 0x3F) >> 6; + return y; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Given a raw sample, 'd', of the difference signal and a + * quantization step size scale factor, 'y', this routine returns the + * ADPCM codeword to which that sample gets quantized. The step + * size scale factor division operation is done in the log base 2 domain + * as a subtraction. + */ +static int16_t quantize(int d, /* Raw difference signal sample */ + int y, /* Step size multiplier */ + const int table[], /* quantization table */ + int quantizer_states) /* table size of int16_t integers */ +{ + int16_t dqm; /* Magnitude of 'd' */ + int16_t exp; /* Integer part of base 2 log of 'd' */ + int16_t mant; /* Fractional part of base 2 log */ + int16_t dl; /* Log of magnitude of 'd' */ + int16_t dln; /* Step size scale factor normalized log */ + int i; + int size; + + /* + * LOG + * + * Compute base 2 log of 'd', and store in 'dl'. + */ + dqm = (int16_t) abs(d); + exp = (int16_t) (top_bit(dqm >> 1) + 1); + /* Fractional portion. */ + mant = ((dqm << 7) >> exp) & 0x7F; + dl = (exp << 7) + mant; + + /* + * SUBTB + * + * "Divide" by step size multiplier. + */ + dln = dl - (int16_t) (y >> 2); + + /* + * QUAN + * + * Search for codword i for 'dln'. + */ + size = (quantizer_states - 1) >> 1; + for (i = 0; i < size; i++) + { + if (dln < table[i]) + break; + } + if (d < 0) + { + /* Take 1's complement of i */ + return (int16_t) ((size << 1) + 1 - i); + } + if (i == 0 && (quantizer_states & 1)) + { + /* Zero is only valid if there are an even number of states, so + take the 1's complement if the code is zero. */ + return (int16_t) quantizer_states; + } + return (int16_t) i; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Returns reconstructed difference signal 'dq' obtained from + * codeword 'i' and quantization step size scale factor 'y'. + * Multiplication is performed in log base 2 domain as addition. + */ +static int16_t reconstruct(int sign, /* 0 for non-negative value */ + int dqln, /* G.72x codeword */ + int y) /* Step size multiplier */ +{ + int16_t dql; /* Log of 'dq' magnitude */ + int16_t dex; /* Integer part of log */ + int16_t dqt; + int16_t dq; /* Reconstructed difference signal sample */ + + dql = (int16_t) (dqln + (y >> 2)); /* ADDA */ + + if (dql < 0) + return ((sign) ? -0x8000 : 0); + /* ANTILOG */ + dex = (dql >> 7) & 15; + dqt = 128 + (dql & 127); + dq = (dqt << 7) >> (14 - dex); + return ((sign) ? (dq - 0x8000) : dq); +} +/*- End of function --------------------------------------------------------*/ + +/* + * updates the state variables for each output code + */ +static void update(g726_state_t *s, + int y, /* quantizer step size */ + int wi, /* scale factor multiplier */ + int fi, /* for long/short term energies */ + int dq, /* quantized prediction difference */ + int sr, /* reconstructed signal */ + int dqsez) /* difference from 2-pole predictor */ +{ + int16_t mag; + int16_t exp; + int16_t a2p; /* LIMC */ + int16_t a1ul; /* UPA1 */ + int16_t pks1; /* UPA2 */ + int16_t fa1; + int16_t ylint; + int16_t dqthr; + int16_t ylfrac; + int16_t thr; + int16_t pk0; + int i; + int tr; + + a2p = 0; + /* Needed in updating predictor poles */ + pk0 = (dqsez < 0) ? 1 : 0; + + /* prediction difference magnitude */ + mag = (int16_t) (dq & 0x7FFF); + /* TRANS */ + ylint = (int16_t) (s->yl >> 15); /* exponent part of yl */ + ylfrac = (int16_t) ((s->yl >> 10) & 0x1F); /* fractional part of yl */ + /* Limit threshold to 31 << 10 */ + thr = (ylint > 9) ? (31 << 10) : ((32 + ylfrac) << ylint); + dqthr = (thr + (thr >> 1)) >> 1; /* dqthr = 0.75 * thr */ + if (!s->td) /* signal supposed voice */ + tr = FALSE; + else if (mag <= dqthr) /* supposed data, but small mag */ + tr = FALSE; /* treated as voice */ + else /* signal is data (modem) */ + tr = TRUE; + + /* + * Quantizer scale factor adaptation. + */ + + /* FUNCTW & FILTD & DELAY */ + /* update non-steady state step size multiplier */ + s->yu = (int16_t) (y + ((wi - y) >> 5)); + + /* LIMB */ + if (s->yu < 544) + s->yu = 544; + else if (s->yu > 5120) + s->yu = 5120; + + /* FILTE & DELAY */ + /* update steady state step size multiplier */ + s->yl += s->yu + ((-s->yl) >> 6); + + /* + * Adaptive predictor coefficients. + */ + if (tr) + { + /* Reset the a's and b's for a modem signal */ + s->a[0] = 0; + s->a[1] = 0; + s->b[0] = 0; + s->b[1] = 0; + s->b[2] = 0; + s->b[3] = 0; + s->b[4] = 0; + s->b[5] = 0; + } + else + { + /* Update the a's and b's */ + /* UPA2 */ + pks1 = pk0 ^ s->pk[0]; + + /* Update predictor pole a[1] */ + a2p = s->a[1] - (s->a[1] >> 7); + if (dqsez != 0) + { + fa1 = (pks1) ? s->a[0] : -s->a[0]; + /* a2p = function of fa1 */ + if (fa1 < -8191) + a2p -= 0x100; + else if (fa1 > 8191) + a2p += 0xFF; + else + a2p += fa1 >> 5; + + if (pk0 ^ s->pk[1]) + { + /* LIMC */ + if (a2p <= -12160) + a2p = -12288; + else if (a2p >= 12416) + a2p = 12288; + else + a2p -= 0x80; + } + else if (a2p <= -12416) + a2p = -12288; + else if (a2p >= 12160) + a2p = 12288; + else + a2p += 0x80; + } + + /* TRIGB & DELAY */ + s->a[1] = a2p; + + /* UPA1 */ + /* Update predictor pole a[0] */ + s->a[0] -= s->a[0] >> 8; + if (dqsez != 0) + { + if (pks1 == 0) + s->a[0] += 192; + else + s->a[0] -= 192; + } + /* LIMD */ + a1ul = 15360 - a2p; + if (s->a[0] < -a1ul) + s->a[0] = -a1ul; + else if (s->a[0] > a1ul) + s->a[0] = a1ul; + + /* UPB : update predictor zeros b[6] */ + for (i = 0; i < 6; i++) + { + /* Distinguish 40Kbps mode from the others */ + s->b[i] -= s->b[i] >> ((s->bits_per_sample == 5) ? 9 : 8); + if (dq & 0x7FFF) + { + /* XOR */ + if ((dq ^ s->dq[i]) >= 0) + s->b[i] += 128; + else + s->b[i] -= 128; + } + } + } + + for (i = 5; i > 0; i--) + s->dq[i] = s->dq[i - 1]; + /* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */ + if (mag == 0) + { + s->dq[0] = (dq >= 0) ? 0x20 : 0xFC20; + } + else + { + exp = (int16_t) (top_bit(mag) + 1); + s->dq[0] = (dq >= 0) + ? ((exp << 6) + ((mag << 6) >> exp)) + : ((exp << 6) + ((mag << 6) >> exp) - 0x400); + } + + s->sr[1] = s->sr[0]; + /* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */ + if (sr == 0) + { + s->sr[0] = 0x20; + } + else if (sr > 0) + { + exp = (int16_t) (top_bit(sr) + 1); + s->sr[0] = (int16_t) ((exp << 6) + ((sr << 6) >> exp)); + } + else if (sr > -32768) + { + mag = (int16_t) -sr; + exp = (int16_t) (top_bit(mag) + 1); + s->sr[0] = (exp << 6) + ((mag << 6) >> exp) - 0x400; + } + else + { + s->sr[0] = (uint16_t) 0xFC20; + } + + /* DELAY A */ + s->pk[1] = s->pk[0]; + s->pk[0] = pk0; + + /* TONE */ + if (tr) /* this sample has been treated as data */ + s->td = FALSE; /* next one will be treated as voice */ + else if (a2p < -11776) /* small sample-to-sample correlation */ + s->td = TRUE; /* signal may be data */ + else /* signal is voice */ + s->td = FALSE; + + /* Adaptation speed control. */ + /* FILTA */ + s->dms += ((int16_t) fi - s->dms) >> 5; + /* FILTB */ + s->dml += (((int16_t) (fi << 2) - s->dml) >> 7); + + if (tr) + s->ap = 256; + else if (y < 1536) /* SUBTC */ + s->ap += (0x200 - s->ap) >> 4; + else if (s->td) + s->ap += (0x200 - s->ap) >> 4; + else if (abs((s->dms << 2) - s->dml) >= (s->dml >> 3)) + s->ap += (0x200 - s->ap) >> 4; + else + s->ap += (-s->ap) >> 4; +} +/*- End of function --------------------------------------------------------*/ + +static int16_t tandem_adjust_alaw(int16_t sr, /* decoder output linear PCM sample */ + int se, /* predictor estimate sample */ + int y, /* quantizer step size */ + int i, /* decoder input code */ + int sign, + const int qtab[], + int quantizer_states) +{ + uint8_t sp; /* A-law compressed 8-bit code */ + int16_t dx; /* prediction error */ + int id; /* quantized prediction error */ + int sd; /* adjusted A-law decoded sample value */ + + if (sr <= -32768) + sr = -1; + sp = linear_to_alaw((sr >> 1) << 3); + /* 16-bit prediction error */ + dx = (int16_t) ((alaw_to_linear(sp) >> 2) - se); + id = quantize(dx, y, qtab, quantizer_states); + if (id == i) + { + /* No adjustment of sp required */ + return (int16_t) sp; + } + /* sp adjustment needed */ + /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */ + /* 2's complement to biased unsigned */ + if ((id ^ sign) > (i ^ sign)) + { + /* sp adjusted to next lower value */ + if (sp & 0x80) + sd = (sp == 0xD5) ? 0x55 : (((sp ^ 0x55) - 1) ^ 0x55); + else + sd = (sp == 0x2A) ? 0x2A : (((sp ^ 0x55) + 1) ^ 0x55); + } + else + { + /* sp adjusted to next higher value */ + if (sp & 0x80) + sd = (sp == 0xAA) ? 0xAA : (((sp ^ 0x55) + 1) ^ 0x55); + else + sd = (sp == 0x55) ? 0xD5 : (((sp ^ 0x55) - 1) ^ 0x55); + } + return (int16_t) sd; +} +/*- End of function --------------------------------------------------------*/ + +static int16_t tandem_adjust_ulaw(int16_t sr, /* decoder output linear PCM sample */ + int se, /* predictor estimate sample */ + int y, /* quantizer step size */ + int i, /* decoder input code */ + int sign, + const int qtab[], + int quantizer_states) +{ + uint8_t sp; /* u-law compressed 8-bit code */ + int16_t dx; /* prediction error */ + int id; /* quantized prediction error */ + int sd; /* adjusted u-law decoded sample value */ + + if (sr <= -32768) + sr = 0; + sp = linear_to_ulaw(sr << 2); + /* 16-bit prediction error */ + dx = (int16_t) ((ulaw_to_linear(sp) >> 2) - se); + id = quantize(dx, y, qtab, quantizer_states); + if (id == i) + { + /* No adjustment of sp required. */ + return (int16_t) sp; + } + /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */ + /* 2's complement to biased unsigned */ + if ((id ^ sign) > (i ^ sign)) + { + /* sp adjusted to next lower value */ + if (sp & 0x80) + sd = (sp == 0xFF) ? 0x7E : (sp + 1); + else + sd = (sp == 0x00) ? 0x00 : (sp - 1); + } + else + { + /* sp adjusted to next higher value */ + if (sp & 0x80) + sd = (sp == 0x80) ? 0x80 : (sp - 1); + else + sd = (sp == 0x7F) ? 0xFE : (sp + 1); + } + return (int16_t) sd; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code. + */ +static uint8_t g726_16_encoder(g726_state_t *s, int16_t amp) +{ + int y; + int16_t sei; + int16_t sezi; + int16_t se; + int16_t d; + int16_t sr; + int16_t dqsez; + int16_t dq; + int16_t i; + + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + se = sei >> 1; + d = amp - se; + + /* Quantize prediction difference */ + y = step_size(s); + i = quantize(d, y, qtab_726_16, 4); + dq = reconstruct(i & 2, g726_16_dqlntab[i], y); + + /* Reconstruct the signal */ + sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_16_witab[i], g726_16_fitab[i], dq, sr, dqsez); + return (uint8_t) i; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Decodes a 2-bit CCITT G.726_16 ADPCM code and returns + * the resulting 16-bit linear PCM, A-law or u-law sample value. + */ +static int16_t g726_16_decoder(g726_state_t *s, uint8_t code) +{ + int16_t sezi; + int16_t sei; + int16_t se; + int16_t sr; + int16_t dq; + int16_t dqsez; + int y; + + /* Mask to get proper bits */ + code &= 0x03; + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + + y = step_size(s); + dq = reconstruct(code & 2, g726_16_dqlntab[code], y); + + /* Reconstruct the signal */ + se = sei >> 1; + sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_16_witab[code], g726_16_fitab[code], dq, sr, dqsez); + + switch (s->ext_coding) + { + case G726_ENCODING_ALAW: + return tandem_adjust_alaw(sr, se, y, code, 2, qtab_726_16, 4); + case G726_ENCODING_ULAW: + return tandem_adjust_ulaw(sr, se, y, code, 2, qtab_726_16, 4); + } + return (sr << 2); +} +/*- End of function --------------------------------------------------------*/ + +/* + * Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code. + */ +static uint8_t g726_24_encoder(g726_state_t *s, int16_t amp) +{ + int16_t sei; + int16_t sezi; + int16_t se; + int16_t d; + int16_t sr; + int16_t dqsez; + int16_t dq; + int16_t i; + int y; + + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + se = sei >> 1; + d = amp - se; + + /* Quantize prediction difference */ + y = step_size(s); + i = quantize(d, y, qtab_726_24, 7); + dq = reconstruct(i & 4, g726_24_dqlntab[i], y); + + /* Reconstruct the signal */ + sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_24_witab[i], g726_24_fitab[i], dq, sr, dqsez); + return (uint8_t) i; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Decodes a 3-bit CCITT G.726_24 ADPCM code and returns + * the resulting 16-bit linear PCM, A-law or u-law sample value. + */ +static int16_t g726_24_decoder(g726_state_t *s, uint8_t code) +{ + int16_t sezi; + int16_t sei; + int16_t se; + int16_t sr; + int16_t dq; + int16_t dqsez; + int y; + + /* Mask to get proper bits */ + code &= 0x07; + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + + y = step_size(s); + dq = reconstruct(code & 4, g726_24_dqlntab[code], y); + + /* Reconstruct the signal */ + se = sei >> 1; + sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_24_witab[code], g726_24_fitab[code], dq, sr, dqsez); + + switch (s->ext_coding) + { + case G726_ENCODING_ALAW: + return tandem_adjust_alaw(sr, se, y, code, 4, qtab_726_24, 7); + case G726_ENCODING_ULAW: + return tandem_adjust_ulaw(sr, se, y, code, 4, qtab_726_24, 7); + } + return (sr << 2); +} +/*- End of function --------------------------------------------------------*/ + +/* + * Encodes a linear input sample and returns its 4-bit code. + */ +static uint8_t g726_32_encoder(g726_state_t *s, int16_t amp) +{ + int16_t sei; + int16_t sezi; + int16_t se; + int16_t d; + int16_t sr; + int16_t dqsez; + int16_t dq; + int16_t i; + int y; + + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + se = sei >> 1; + d = amp - se; + + /* Quantize the prediction difference */ + y = step_size(s); + i = quantize(d, y, qtab_726_32, 15); + dq = reconstruct(i & 8, g726_32_dqlntab[i], y); + + /* Reconstruct the signal */ + sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_32_witab[i], g726_32_fitab[i], dq, sr, dqsez); + return (uint8_t) i; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Decodes a 4-bit CCITT G.726_32 ADPCM code and returns + * the resulting 16-bit linear PCM, A-law or u-law sample value. + */ +static int16_t g726_32_decoder(g726_state_t *s, uint8_t code) +{ + int16_t sezi; + int16_t sei; + int16_t se; + int16_t sr; + int16_t dq; + int16_t dqsez; + int y; + + /* Mask to get proper bits */ + code &= 0x0F; + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + + y = step_size(s); + dq = reconstruct(code & 8, g726_32_dqlntab[code], y); + + /* Reconstruct the signal */ + se = sei >> 1; + sr = (dq < 0) ? (se - (dq & 0x3FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_32_witab[code], g726_32_fitab[code], dq, sr, dqsez); + + switch (s->ext_coding) + { + case G726_ENCODING_ALAW: + return tandem_adjust_alaw(sr, se, y, code, 8, qtab_726_32, 15); + case G726_ENCODING_ULAW: + return tandem_adjust_ulaw(sr, se, y, code, 8, qtab_726_32, 15); + } + return (sr << 2); +} +/*- End of function --------------------------------------------------------*/ + +/* + * Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens + * the resulting 5-bit CCITT G.726 40Kbps code. + */ +static uint8_t g726_40_encoder(g726_state_t *s, int16_t amp) +{ + int16_t sei; + int16_t sezi; + int16_t se; + int16_t d; + int16_t sr; + int16_t dqsez; + int16_t dq; + int16_t i; + int y; + + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + se = sei >> 1; + d = amp - se; + + /* Quantize prediction difference */ + y = step_size(s); + i = quantize(d, y, qtab_726_40, 31); + dq = reconstruct(i & 0x10, g726_40_dqlntab[i], y); + + /* Reconstruct the signal */ + sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_40_witab[i], g726_40_fitab[i], dq, sr, dqsez); + return (uint8_t) i; +} +/*- End of function --------------------------------------------------------*/ + +/* + * Decodes a 5-bit CCITT G.726 40Kbps code and returns + * the resulting 16-bit linear PCM, A-law or u-law sample value. + */ +static int16_t g726_40_decoder(g726_state_t *s, uint8_t code) +{ + int16_t sezi; + int16_t sei; + int16_t se; + int16_t sr; + int16_t dq; + int16_t dqsez; + int y; + + /* Mask to get proper bits */ + code &= 0x1F; + sezi = predictor_zero(s); + sei = sezi + predictor_pole(s); + + y = step_size(s); + dq = reconstruct(code & 0x10, g726_40_dqlntab[code], y); + + /* Reconstruct the signal */ + se = sei >> 1; + sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq); + + /* Pole prediction difference */ + dqsez = sr + (sezi >> 1) - se; + + update(s, y, g726_40_witab[code], g726_40_fitab[code], dq, sr, dqsez); + + switch (s->ext_coding) + { + case G726_ENCODING_ALAW: + return tandem_adjust_alaw(sr, se, y, code, 0x10, qtab_726_40, 31); + case G726_ENCODING_ULAW: + return tandem_adjust_ulaw(sr, se, y, code, 0x10, qtab_726_40, 31); + } + return (sr << 2); +} +/*- End of function --------------------------------------------------------*/ + +g726_state_t *g726_init(g726_state_t *s, int bit_rate, int ext_coding, int packing) +{ + int i; + + if (bit_rate != 16000 && bit_rate != 24000 && bit_rate != 32000 && bit_rate != 40000) + return NULL; + if (s == NULL) + { + if ((s = (g726_state_t *) malloc(sizeof(*s))) == NULL) + return NULL; + } + s->yl = 34816; + s->yu = 544; + s->dms = 0; + s->dml = 0; + s->ap = 0; + s->rate = bit_rate; + s->ext_coding = ext_coding; + s->packing = packing; + for (i = 0; i < 2; i++) + { + s->a[i] = 0; + s->pk[i] = 0; + s->sr[i] = 32; + } + for (i = 0; i < 6; i++) + { + s->b[i] = 0; + s->dq[i] = 32; + } + s->td = FALSE; + switch (bit_rate) + { + case 16000: + s->enc_func = g726_16_encoder; + s->dec_func = g726_16_decoder; + s->bits_per_sample = 2; + break; + case 24000: + s->enc_func = g726_24_encoder; + s->dec_func = g726_24_decoder; + s->bits_per_sample = 3; + break; + case 32000: + default: + s->enc_func = g726_32_encoder; + s->dec_func = g726_32_decoder; + s->bits_per_sample = 4; + break; + case 40000: + s->enc_func = g726_40_encoder; + s->dec_func = g726_40_decoder; + s->bits_per_sample = 5; + break; + } + bitstream_init(&s->bs); + return s; +} +/*- End of function --------------------------------------------------------*/ + +int g726_release(g726_state_t *s) +{ + free(s); + return 0; +} +/*- End of function --------------------------------------------------------*/ + +int g726_decode(g726_state_t *s, + int16_t amp[], + const uint8_t g726_data[], + int g726_bytes) +{ + int i; + int samples; + uint8_t code; + int sl; + + for (samples = i = 0; ; ) + { + if (s->packing != G726_PACKING_NONE) + { + /* Unpack the code bits */ + if (s->packing != G726_PACKING_LEFT) + { + if (s->bs.residue < s->bits_per_sample) + { + if (i >= g726_bytes) + break; + s->bs.bitstream |= (g726_data[i++] << s->bs.residue); + s->bs.residue += 8; + } + code = (uint8_t) (s->bs.bitstream & ((1 << s->bits_per_sample) - 1)); + s->bs.bitstream >>= s->bits_per_sample; + } + else + { + if (s->bs.residue < s->bits_per_sample) + { + if (i >= g726_bytes) + break; + s->bs.bitstream = (s->bs.bitstream << 8) | g726_data[i++]; + s->bs.residue += 8; + } + code = (uint8_t) ((s->bs.bitstream >> (s->bs.residue - s->bits_per_sample)) & ((1 << s->bits_per_sample) - 1)); + } + s->bs.residue -= s->bits_per_sample; + } + else + { + if (i >= g726_bytes) + break; + code = g726_data[i++]; + } + sl = s->dec_func(s, code); + if (s->ext_coding != G726_ENCODING_LINEAR) + ((uint8_t *) amp)[samples++] = (uint8_t) sl; + else + amp[samples++] = (int16_t) sl; + } + return samples; +} +/*- End of function --------------------------------------------------------*/ + +int g726_encode(g726_state_t *s, + uint8_t g726_data[], + const int16_t amp[], + int len) +{ + int i; + int g726_bytes; + int16_t sl; + uint8_t code; + + for (g726_bytes = i = 0; i < len; i++) + { + /* Linearize the input sample to 14-bit PCM */ + switch (s->ext_coding) + { + case G726_ENCODING_ALAW: + sl = alaw_to_linear(((const uint8_t *) amp)[i]) >> 2; + break; + case G726_ENCODING_ULAW: + sl = ulaw_to_linear(((const uint8_t *) amp)[i]) >> 2; + break; + default: + sl = amp[i] >> 2; + break; + } + code = s->enc_func(s, sl); + if (s->packing != G726_PACKING_NONE) + { + /* Pack the code bits */ + if (s->packing != G726_PACKING_LEFT) + { + s->bs.bitstream |= (code << s->bs.residue); + s->bs.residue += s->bits_per_sample; + if (s->bs.residue >= 8) + { + g726_data[g726_bytes++] = (uint8_t) (s->bs.bitstream & 0xFF); + s->bs.bitstream >>= 8; + s->bs.residue -= 8; + } + } + else + { + s->bs.bitstream = (s->bs.bitstream << s->bits_per_sample) | code; + s->bs.residue += s->bits_per_sample; + if (s->bs.residue >= 8) + { + g726_data[g726_bytes++] = (uint8_t) ((s->bs.bitstream >> (s->bs.residue - 8)) & 0xFF); + s->bs.residue -= 8; + } + } + } + else + { + g726_data[g726_bytes++] = (uint8_t) code; + } + } + return g726_bytes; +} +/*- End of function --------------------------------------------------------*/ +/*- End of file ------------------------------------------------------------*/