ref: 590bc2de9d6d4914cca99186a1c56cf78b693b0c
dir: /src/g72x.c/
/* * 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 */ /* * g72x.c * * Common routines for G.721 and G.723 conversions. */ #include "st.h" #include "libst.h" #include "g72x.h" static short power2[15] = {1, 2, 4, 8, 0x10, 0x20, 0x40, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000}; /* * quan() * * quantizes the input val against the table of size short integers. * It returns i if table[i - 1] <= val < table[i]. * * Using linear search for simple coding. */ static int quan(val,table,size) int val; short *table; int size; { int i; for (i = 0; i < size; i++) if (val < *table++) break; return (i); } /* * fmult() * * returns the integer product of the 14-bit integer "an" and * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn". */ static int fmult(an, srn) int an; int srn; { short anmag, anexp, anmant; short wanexp, wanmant; short retval; anmag = (an > 0) ? an : ((-an) & 0x1FFF); anexp = quan(anmag, power2, 15) - 6; anmant = (anmag == 0) ? 32 : (anexp >= 0) ? anmag >> anexp : anmag << -anexp; wanexp = anexp + ((srn >> 6) & 0xF) - 13; wanmant = (anmant * (srn & 077) + 0x30) >> 4; retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) : (wanmant >> -wanexp); return (((an ^ srn) < 0) ? -retval : retval); } /* * g72x_init_state() * * This routine initializes and/or resets the g72x_state structure * pointed to by 'state_ptr'. * All the initial state values are specified in the CCITT G.721 document. */ void g72x_init_state(state_ptr) struct g72x_state *state_ptr; { int cnta; state_ptr->yl = 34816L; state_ptr->yu = 544; state_ptr->dms = 0; state_ptr->dml = 0; state_ptr->ap = 0; for (cnta = 0; cnta < 2; cnta++) { state_ptr->a[cnta] = 0; state_ptr->pk[cnta] = 0; state_ptr->sr[cnta] = 32; } for (cnta = 0; cnta < 6; cnta++) { state_ptr->b[cnta] = 0; state_ptr->dq[cnta] = 32; } state_ptr->td = 0; } /* * predictor_zero() * * computes the estimated signal from 6-zero predictor. * */ int predictor_zero(state_ptr) struct g72x_state *state_ptr; { int i; int sezi; sezi = fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]); for (i = 1; i < 6; i++) /* ACCUM */ sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]); return (sezi); } /* * predictor_pole() * * computes the estimated signal from 2-pole predictor. * */ int predictor_pole(state_ptr) struct g72x_state *state_ptr; { return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) + fmult(state_ptr->a[0] >> 2, state_ptr->sr[0])); } /* * step_size() * * computes the quantization step size of the adaptive quantizer. * */ int step_size(state_ptr) struct g72x_state *state_ptr; { int y; int dif; int al; if (state_ptr->ap >= 256) return (state_ptr->yu); else { y = state_ptr->yl >> 6; dif = state_ptr->yu - y; al = state_ptr->ap >> 2; if (dif > 0) y += (dif * al) >> 6; else if (dif < 0) y += (dif * al + 0x3F) >> 6; return (y); } } /* * quantize() * * 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. */ int quantize(d, y,table,size) int d; /* Raw difference signal sample */ int y; /* Step size multiplier */ short *table; /* quantization table */ int size; /* table size of short integers */ { short dqm; /* Magnitude of 'd' */ short exp; /* Integer part of base 2 log of 'd' */ short mant; /* Fractional part of base 2 log */ short dl; /* Log of magnitude of 'd' */ short dln; /* Step size scale factor normalized log */ int i; /* * LOG * * Compute base 2 log of 'd', and store in 'dl'. */ dqm = abs(d); exp = quan(dqm >> 1, power2, 15); mant = ((dqm << 7) >> exp) & 0x7F; /* Fractional portion. */ dl = (exp << 7) + mant; /* * SUBTB * * "Divide" by step size multiplier. */ dln = dl - (y >> 2); /* * QUAN * * Obtain codword i for 'd'. */ i = quan(dln, table, size); if (d < 0) /* take 1's complement of i */ return ((size << 1) + 1 - i); else if (i == 0) /* take 1's complement of 0 */ return ((size << 1) + 1); /* new in 1988 */ else return (i); } /* * reconstruct() * * 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. */ int reconstruct(sign, dqln, y) int sign; /* 0 for non-negative value */ int dqln; /* G.72x codeword */ int y; /* Step size multiplier */ { short dql; /* Log of 'dq' magnitude */ short dex; /* Integer part of log */ short dqt; short dq; /* Reconstructed difference signal sample */ dql = dqln + (y >> 2); /* ADDA */ if (dql < 0) { return ((sign) ? -0x8000 : 0); } else { /* ANTILOG */ dex = (dql >> 7) & 15; dqt = 128 + (dql & 127); dq = (dqt << 7) >> (14 - dex); return ((sign) ? (dq - 0x8000) : dq); } } /* * update() * * updates the state variables for each output code */ void update(code_size, y, wi, fi, dq, sr, dqsez, state_ptr) int code_size; /* distinguish 723_40 with others */ 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 */ struct g72x_state *state_ptr; /* coder state pointer */ { int cnt; short mag, exp; /* Adaptive predictor, FLOAT A */ short a2p=0; /* LIMC */ short a1ul; /* UPA1 */ short pks1; /* UPA2 */ short fa1; char tr; /* tone/transition detector */ short ylint, thr2, dqthr; short ylfrac, thr1; short pk0; pk0 = (dqsez < 0) ? 1 : 0; /* needed in updating predictor poles */ mag = dq & 0x7FFF; /* prediction difference magnitude */ /* TRANS */ ylint = state_ptr->yl >> 15; /* exponent part of yl */ ylfrac = (state_ptr->yl >> 10) & 0x1F; /* fractional part of yl */ thr1 = (32 + ylfrac) << ylint; /* threshold */ thr2 = (ylint > 9) ? 31 << 10 : thr1; /* limit thr2 to 31 << 10 */ dqthr = (thr2 + (thr2 >> 1)) >> 1; /* dqthr = 0.75 * thr2 */ if (state_ptr->td == 0) /* signal supposed voice */ tr = 0; else if (mag <= dqthr) /* supposed data, but small mag */ tr = 0; /* treated as voice */ else /* signal is data (modem) */ tr = 1; /* * Quantizer scale factor adaptation. */ /* FUNCTW & FILTD & DELAY */ /* update non-steady state step size multiplier */ state_ptr->yu = y + ((wi - y) >> 5); /* LIMB */ if (state_ptr->yu < 544) /* 544 <= yu <= 5120 */ state_ptr->yu = 544; else if (state_ptr->yu > 5120) state_ptr->yu = 5120; /* FILTE & DELAY */ /* update steady state step size multiplier */ state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6); /* * Adaptive predictor coefficients. */ if (tr == 1) { /* reset a's and b's for modem signal */ state_ptr->a[0] = 0; state_ptr->a[1] = 0; state_ptr->b[0] = 0; state_ptr->b[1] = 0; state_ptr->b[2] = 0; state_ptr->b[3] = 0; state_ptr->b[4] = 0; state_ptr->b[5] = 0; } else { /* update a's and b's */ pks1 = pk0 ^ state_ptr->pk[0]; /* UPA2 */ /* update predictor pole a[1] */ a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7); if (dqsez != 0) { fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0]; if (fa1 < -8191) /* a2p = function of fa1 */ a2p -= 0x100; else if (fa1 > 8191) a2p += 0xFF; else a2p += fa1 >> 5; if (pk0 ^ state_ptr->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; } /* Possible bug: a2p not initialized if dqsez == 0) */ /* TRIGB & DELAY */ state_ptr->a[1] = a2p; /* UPA1 */ /* update predictor pole a[0] */ state_ptr->a[0] -= state_ptr->a[0] >> 8; if (dqsez != 0) if (pks1 == 0) state_ptr->a[0] += 192; else state_ptr->a[0] -= 192; /* LIMD */ a1ul = 15360 - a2p; if (state_ptr->a[0] < -a1ul) state_ptr->a[0] = -a1ul; else if (state_ptr->a[0] > a1ul) state_ptr->a[0] = a1ul; /* UPB : update predictor zeros b[6] */ for (cnt = 0; cnt < 6; cnt++) { if (code_size == 5) /* for 40Kbps G.723 */ state_ptr->b[cnt] -= state_ptr->b[cnt] >> 9; else /* for G.721 and 24Kbps G.723 */ state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8; if (dq & 0x7FFF) { /* XOR */ if ((dq ^ state_ptr->dq[cnt]) >= 0) state_ptr->b[cnt] += 128; else state_ptr->b[cnt] -= 128; } } } for (cnt = 5; cnt > 0; cnt--) state_ptr->dq[cnt] = state_ptr->dq[cnt-1]; /* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */ if (mag == 0) { state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0xFC20; } else { exp = quan(mag, power2, 15); state_ptr->dq[0] = (dq >= 0) ? (exp << 6) + ((mag << 6) >> exp) : (exp << 6) + ((mag << 6) >> exp) - 0x400; } state_ptr->sr[1] = state_ptr->sr[0]; /* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */ if (sr == 0) { state_ptr->sr[0] = 0x20; } else if (sr > 0) { exp = quan(sr, power2, 15); state_ptr->sr[0] = (exp << 6) + ((sr << 6) >> exp); } else if (sr > -32768L) { mag = -sr; exp = quan(mag, power2, 15); state_ptr->sr[0] = (exp << 6) + ((mag << 6) >> exp) - 0x400; } else state_ptr->sr[0] = 0xFC20; /* DELAY A */ state_ptr->pk[1] = state_ptr->pk[0]; state_ptr->pk[0] = pk0; /* TONE */ if (tr == 1) /* this sample has been treated as data */ state_ptr->td = 0; /* next one will be treated as voice */ else if (a2p < -11776) /* small sample-to-sample correlation */ state_ptr->td = 1; /* signal may be data */ else /* signal is voice */ state_ptr->td = 0; /* * Adaptation speed control. */ state_ptr->dms += (fi - state_ptr->dms) >> 5; /* FILTA */ state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7); /* FILTB */ if (tr == 1) state_ptr->ap = 256; else if (y < 1536) /* SUBTC */ state_ptr->ap += (0x200 - state_ptr->ap) >> 4; else if (state_ptr->td == 1) state_ptr->ap += (0x200 - state_ptr->ap) >> 4; else if (abs((state_ptr->dms << 2) - state_ptr->dml) >= (state_ptr->dml >> 3)) state_ptr->ap += (0x200 - state_ptr->ap) >> 4; else state_ptr->ap += (-state_ptr->ap) >> 4; } /* * tandem_adjust(sr, se, y, i, sign) * * At the end of ADPCM decoding, it simulates an encoder which may be receiving * the output of this decoder as a tandem process. If the output of the * simulated encoder differs from the input to this decoder, the decoder output * is adjusted by one level of A-law or u-law codes. * * Input: * sr decoder output linear PCM sample, * se predictor estimate sample, * y quantizer step size, * i decoder input code, * sign sign bit of code i * * Return: * adjusted A-law or u-law compressed sample. */ int tandem_adjust_alaw(sr, se, y, i, sign, qtab) int sr; /* decoder output linear PCM sample */ int se; /* predictor estimate sample */ int y; /* quantizer step size */ int i; /* decoder input code */ int sign; short *qtab; { unsigned char sp; /* A-law compressed 8-bit code */ short dx; /* prediction error */ char id; /* quantized prediction error */ int sd; /* adjusted A-law decoded sample value */ int im; /* biased magnitude of i */ int imx; /* biased magnitude of id */ if (sr <= -32768L) sr = -1; sp = st_linear_to_Alaw((sr >> 1) << 3); /* short to A-law compression */ dx = (st_Alaw_to_linear(sp) >> 2) - se; /* 16-bit prediction error */ id = quantize(dx, y, qtab, sign - 1); if (id == i) { /* no adjustment on sp */ return (sp); } else { /* sp adjustment needed */ /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */ im = i ^ sign; /* 2's complement to biased unsigned */ imx = id ^ sign; if (imx > im) { /* 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 (sd); } } int tandem_adjust_ulaw(sr, se, y, i, sign, qtab) int sr; /* decoder output linear PCM sample */ int se; /* predictor estimate sample */ int y; /* quantizer step size */ int i; /* decoder input code */ int sign; short *qtab; { unsigned char sp; /* u-law compressed 8-bit code */ short dx; /* prediction error */ char id; /* quantized prediction error */ int sd; /* adjusted u-law decoded sample value */ int im; /* biased magnitude of i */ int imx; /* biased magnitude of id */ if (sr <= -32768L) sr = 0; sp = st_linear_to_ulaw(sr << 2); /* short to u-law compression */ dx = (st_ulaw_to_linear(sp) >> 2) - se; /* 16-bit prediction error */ id = quantize(dx, y, qtab, sign - 1); if (id == i) { return (sp); } else { /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */ im = i ^ sign; /* 2's complement to biased unsigned */ imx = id ^ sign; if (imx > im) { /* sp adjusted to next lower value */ if (sp & 0x80) sd = (sp == 0xFF) ? 0x7E : sp + 1; else sd = (sp == 0) ? 0 : 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 (sd); } }