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ffmpeg/libavcodec/liba52/parse.c

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/*
* parse.c
* Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
*
* This file is part of a52dec, a free ATSC A-52 stream decoder.
* See http://liba52.sourceforge.net/ for updates.
*
* a52dec is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* a52dec 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "a52.h"
#include "a52_internal.h"
#include "bitstream.h"
#include "tables.h"
#ifdef HAVE_MEMALIGN
/* some systems have memalign() but no declaration for it */
void * memalign (size_t align, size_t size);
#else
/* assume malloc alignment is sufficient */
#define memalign(align,size) malloc (size)
#endif
typedef struct {
sample_t q1[2];
sample_t q2[2];
sample_t q4;
int q1_ptr;
int q2_ptr;
int q4_ptr;
} quantizer_t;
static uint8_t halfrate[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3};
a52_state_t * a52_init (uint32_t mm_accel)
{
a52_state_t * state;
int i;
state = malloc (sizeof (a52_state_t));
if (state == NULL)
return NULL;
state->samples = memalign (16, 256 * 12 * sizeof (sample_t));
if (state->samples == NULL) {
free (state);
return NULL;
}
for (i = 0; i < 256 * 12; i++)
state->samples[i] = 0;
state->downmixed = 1;
a52_imdct_init (mm_accel);
return state;
}
sample_t * a52_samples (a52_state_t * state)
{
return state->samples;
}
int a52_syncinfo (uint8_t * buf, int * flags,
int * sample_rate, int * bit_rate)
{
static int rate[] = { 32, 40, 48, 56, 64, 80, 96, 112,
128, 160, 192, 224, 256, 320, 384, 448,
512, 576, 640};
static uint8_t lfeon[8] = {0x10, 0x10, 0x04, 0x04, 0x04, 0x01, 0x04, 0x01};
int frmsizecod;
int bitrate;
int half;
int acmod;
if ((buf[0] != 0x0b) || (buf[1] != 0x77)) /* syncword */
return 0;
if (buf[5] >= 0x60) /* bsid >= 12 */
return 0;
half = halfrate[buf[5] >> 3];
/* acmod, dsurmod and lfeon */
acmod = buf[6] >> 5;
*flags = ((((buf[6] & 0xf8) == 0x50) ? A52_DOLBY : acmod) |
((buf[6] & lfeon[acmod]) ? A52_LFE : 0));
frmsizecod = buf[4] & 63;
if (frmsizecod >= 38)
return 0;
bitrate = rate [frmsizecod >> 1];
*bit_rate = (bitrate * 1000) >> half;
switch (buf[4] & 0xc0) {
case 0:
*sample_rate = 48000 >> half;
return 4 * bitrate;
case 0x40:
*sample_rate = 44100 >> half;
return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
case 0x80:
*sample_rate = 32000 >> half;
return 6 * bitrate;
default:
return 0;
}
}
int a52_frame (a52_state_t * state, uint8_t * buf, int * flags,
sample_t * level, sample_t bias)
{
static sample_t clev[4] = {LEVEL_3DB, LEVEL_45DB, LEVEL_6DB, LEVEL_45DB};
static sample_t slev[4] = {LEVEL_3DB, LEVEL_6DB, 0, LEVEL_6DB};
int chaninfo;
int acmod;
state->fscod = buf[4] >> 6;
state->halfrate = halfrate[buf[5] >> 3];
state->acmod = acmod = buf[6] >> 5;
a52_bitstream_set_ptr (buf + 6);
bitstream_get (3); /* skip acmod we already parsed */
if ((acmod == 2) && (bitstream_get (2) == 2)) /* dsurmod */
acmod = A52_DOLBY;
if ((acmod & 1) && (acmod != 1))
state->clev = clev[bitstream_get (2)]; /* cmixlev */
if (acmod & 4)
state->slev = slev[bitstream_get (2)]; /* surmixlev */
state->lfeon = bitstream_get (1);
state->output = a52_downmix_init (acmod, *flags, level,
state->clev, state->slev);
if (state->output < 0)
return 1;
if (state->lfeon && (*flags & A52_LFE))
state->output |= A52_LFE;
*flags = state->output;
/* the 2* compensates for differences in imdct */
state->dynrng = state->level = 2 * *level;
state->bias = bias;
state->dynrnge = 1;
state->dynrngcall = NULL;
state->cplba.deltbae = DELTA_BIT_NONE;
state->ba[0].deltbae = state->ba[1].deltbae = state->ba[2].deltbae =
state->ba[3].deltbae = state->ba[4].deltbae = DELTA_BIT_NONE;
chaninfo = !acmod;
do {
bitstream_get (5); /* dialnorm */
if (bitstream_get (1)) /* compre */
bitstream_get (8); /* compr */
if (bitstream_get (1)) /* langcode */
bitstream_get (8); /* langcod */
if (bitstream_get (1)) /* audprodie */
bitstream_get (7); /* mixlevel + roomtyp */
} while (chaninfo--);
bitstream_get (2); /* copyrightb + origbs */
if (bitstream_get (1)) /* timecod1e */
bitstream_get (14); /* timecod1 */
if (bitstream_get (1)) /* timecod2e */
bitstream_get (14); /* timecod2 */
if (bitstream_get (1)) { /* addbsie */
int addbsil;
addbsil = bitstream_get (6);
do {
bitstream_get (8); /* addbsi */
} while (addbsil--);
}
return 0;
}
void a52_dynrng (a52_state_t * state,
sample_t (* call) (sample_t, void *), void * data)
{
state->dynrnge = 0;
if (call) {
state->dynrnge = 1;
state->dynrngcall = call;
state->dynrngdata = data;
}
}
static int parse_exponents (int expstr, int ngrps, uint8_t exponent,
uint8_t * dest)
{
int exps;
while (ngrps--) {
exps = bitstream_get (7);
exponent += exp_1[exps];
if (exponent > 24)
return 1;
switch (expstr) {
case EXP_D45:
*(dest++) = exponent;
*(dest++) = exponent;
case EXP_D25:
*(dest++) = exponent;
case EXP_D15:
*(dest++) = exponent;
}
exponent += exp_2[exps];
if (exponent > 24)
return 1;
switch (expstr) {
case EXP_D45:
*(dest++) = exponent;
*(dest++) = exponent;
case EXP_D25:
*(dest++) = exponent;
case EXP_D15:
*(dest++) = exponent;
}
exponent += exp_3[exps];
if (exponent > 24)
return 1;
switch (expstr) {
case EXP_D45:
*(dest++) = exponent;
*(dest++) = exponent;
case EXP_D25:
*(dest++) = exponent;
case EXP_D15:
*(dest++) = exponent;
}
}
return 0;
}
static int parse_deltba (int8_t * deltba)
{
int deltnseg, deltlen, delta, j;
memset (deltba, 0, 50);
deltnseg = bitstream_get (3);
j = 0;
do {
j += bitstream_get (5);
deltlen = bitstream_get (4);
delta = bitstream_get (3);
delta -= (delta >= 4) ? 3 : 4;
if (!deltlen)
continue;
if (j + deltlen >= 50)
return 1;
while (deltlen--)
deltba[j++] = delta;
} while (deltnseg--);
return 0;
}
static inline int zero_snr_offsets (int nfchans, a52_state_t * state)
{
int i;
if ((state->csnroffst) ||
(state->chincpl && state->cplba.bai >> 3) || /* cplinu, fsnroffst */
(state->lfeon && state->lfeba.bai >> 3)) /* fsnroffst */
return 0;
for (i = 0; i < nfchans; i++)
if (state->ba[i].bai >> 3) /* fsnroffst */
return 0;
return 1;
}
static inline int16_t dither_gen (void)
{
static uint16_t lfsr_state = 1;
int16_t state;
state = dither_lut[lfsr_state >> 8] ^ (lfsr_state << 8);
lfsr_state = (uint16_t) state;
return state;
}
static void coeff_get (sample_t * coeff, expbap_t * expbap,
quantizer_t * quantizer, sample_t level,
int dither, int end)
{
int i;
uint8_t * exp;
int8_t * bap;
sample_t factor[25];
for (i = 0; i <= 24; i++)
factor[i] = scale_factor[i] * level;
exp = expbap->exp;
bap = expbap->bap;
for (i = 0; i < end; i++) {
int bapi;
bapi = bap[i];
switch (bapi) {
case 0:
if (dither) {
coeff[i] = dither_gen() * LEVEL_3DB * factor[exp[i]];
continue;
} else {
coeff[i] = 0;
continue;
}
case -1:
if (quantizer->q1_ptr >= 0) {
coeff[i] = quantizer->q1[quantizer->q1_ptr--] * factor[exp[i]];
continue;
} else {
int code;
code = bitstream_get (5);
quantizer->q1_ptr = 1;
quantizer->q1[0] = q_1_2[code];
quantizer->q1[1] = q_1_1[code];
coeff[i] = q_1_0[code] * factor[exp[i]];
continue;
}
case -2:
if (quantizer->q2_ptr >= 0) {
coeff[i] = quantizer->q2[quantizer->q2_ptr--] * factor[exp[i]];
continue;
} else {
int code;
code = bitstream_get (7);
quantizer->q2_ptr = 1;
quantizer->q2[0] = q_2_2[code];
quantizer->q2[1] = q_2_1[code];
coeff[i] = q_2_0[code] * factor[exp[i]];
continue;
}
case 3:
coeff[i] = q_3[bitstream_get (3)] * factor[exp[i]];
continue;
case -3:
if (quantizer->q4_ptr == 0) {
quantizer->q4_ptr = -1;
coeff[i] = quantizer->q4 * factor[exp[i]];
continue;
} else {
int code;
code = bitstream_get (7);
quantizer->q4_ptr = 0;
quantizer->q4 = q_4_1[code];
coeff[i] = q_4_0[code] * factor[exp[i]];
continue;
}
case 4:
coeff[i] = q_5[bitstream_get (4)] * factor[exp[i]];
continue;
default:
coeff[i] = ((bitstream_get_2 (bapi) << (16 - bapi)) *
factor[exp[i]]);
}
}
}
static void coeff_get_coupling (a52_state_t * state, int nfchans,
sample_t * coeff, sample_t (* samples)[256],
quantizer_t * quantizer, uint8_t dithflag[5])
{
int cplbndstrc, bnd, i, i_end, ch;
uint8_t * exp;
int8_t * bap;
sample_t cplco[5];
exp = state->cpl_expbap.exp;
bap = state->cpl_expbap.bap;
bnd = 0;
cplbndstrc = state->cplbndstrc;
i = state->cplstrtmant;
while (i < state->cplendmant) {
i_end = i + 12;
while (cplbndstrc & 1) {
cplbndstrc >>= 1;
i_end += 12;
}
cplbndstrc >>= 1;
for (ch = 0; ch < nfchans; ch++)
cplco[ch] = state->cplco[ch][bnd] * coeff[ch];
bnd++;
while (i < i_end) {
sample_t cplcoeff;
int bapi;
bapi = bap[i];
switch (bapi) {
case 0:
cplcoeff = LEVEL_3DB * scale_factor[exp[i]];
for (ch = 0; ch < nfchans; ch++)
if ((state->chincpl >> ch) & 1) {
if (dithflag[ch])
samples[ch][i] = (cplcoeff * cplco[ch] *
dither_gen ());
else
samples[ch][i] = 0;
}
i++;
continue;
case -1:
if (quantizer->q1_ptr >= 0) {
cplcoeff = quantizer->q1[quantizer->q1_ptr--];
break;
} else {
int code;
code = bitstream_get (5);
quantizer->q1_ptr = 1;
quantizer->q1[0] = q_1_2[code];
quantizer->q1[1] = q_1_1[code];
cplcoeff = q_1_0[code];
break;
}
case -2:
if (quantizer->q2_ptr >= 0) {
cplcoeff = quantizer->q2[quantizer->q2_ptr--];
break;
} else {
int code;
code = bitstream_get (7);
quantizer->q2_ptr = 1;
quantizer->q2[0] = q_2_2[code];
quantizer->q2[1] = q_2_1[code];
cplcoeff = q_2_0[code];
break;
}
case 3:
cplcoeff = q_3[bitstream_get (3)];
break;
case -3:
if (quantizer->q4_ptr == 0) {
quantizer->q4_ptr = -1;
cplcoeff = quantizer->q4;
break;
} else {
int code;
code = bitstream_get (7);
quantizer->q4_ptr = 0;
quantizer->q4 = q_4_1[code];
cplcoeff = q_4_0[code];
break;
}
case 4:
cplcoeff = q_5[bitstream_get (4)];
break;
default:
cplcoeff = bitstream_get_2 (bapi) << (16 - bapi);
}
cplcoeff *= scale_factor[exp[i]];
for (ch = 0; ch < nfchans; ch++)
if ((state->chincpl >> ch) & 1)
samples[ch][i] = cplcoeff * cplco[ch];
i++;
}
}
}
int a52_block (a52_state_t * state)
{
static const uint8_t nfchans_tbl[] = {2, 1, 2, 3, 3, 4, 4, 5, 1, 1, 2};
static int rematrix_band[4] = {25, 37, 61, 253};
int i, nfchans, chaninfo;
uint8_t cplexpstr, chexpstr[5], lfeexpstr, do_bit_alloc, done_cpl;
uint8_t blksw[5], dithflag[5];
sample_t coeff[5];
int chanbias;
quantizer_t quantizer;
sample_t * samples;
nfchans = nfchans_tbl[state->acmod];
for (i = 0; i < nfchans; i++)
blksw[i] = bitstream_get (1);
for (i = 0; i < nfchans; i++)
dithflag[i] = bitstream_get (1);
chaninfo = !state->acmod;
do {
if (bitstream_get (1)) { /* dynrnge */
int dynrng;
dynrng = bitstream_get_2 (8);
if (state->dynrnge) {
sample_t range;
range = ((((dynrng & 0x1f) | 0x20) << 13) *
scale_factor[3 - (dynrng >> 5)]);
if (state->dynrngcall)
range = state->dynrngcall (range, state->dynrngdata);
state->dynrng = state->level * range;
}
}
} while (chaninfo--);
if (bitstream_get (1)) { /* cplstre */
state->chincpl = 0;
if (bitstream_get (1)) { /* cplinu */
static uint8_t bndtab[16] = {31, 35, 37, 39, 41, 42, 43, 44,
45, 45, 46, 46, 47, 47, 48, 48};
int cplbegf;
int cplendf;
int ncplsubnd;
for (i = 0; i < nfchans; i++)
state->chincpl |= bitstream_get (1) << i;
switch (state->acmod) {
case 0: case 1:
return 1;
case 2:
state->phsflginu = bitstream_get (1);
}
cplbegf = bitstream_get (4);
cplendf = bitstream_get (4);
if (cplendf + 3 - cplbegf < 0)
return 1;
state->ncplbnd = ncplsubnd = cplendf + 3 - cplbegf;
state->cplstrtbnd = bndtab[cplbegf];
state->cplstrtmant = cplbegf * 12 + 37;
state->cplendmant = cplendf * 12 + 73;
state->cplbndstrc = 0;
for (i = 0; i < ncplsubnd - 1; i++)
if (bitstream_get (1)) {
state->cplbndstrc |= 1 << i;
state->ncplbnd--;
}
}
}
if (state->chincpl) { /* cplinu */
int j, cplcoe;
cplcoe = 0;
for (i = 0; i < nfchans; i++)
if ((state->chincpl) >> i & 1)
if (bitstream_get (1)) { /* cplcoe */
int mstrcplco, cplcoexp, cplcomant;
cplcoe = 1;
mstrcplco = 3 * bitstream_get (2);
for (j = 0; j < state->ncplbnd; j++) {
cplcoexp = bitstream_get (4);
cplcomant = bitstream_get (4);
if (cplcoexp == 15)
cplcomant <<= 14;
else
cplcomant = (cplcomant | 0x10) << 13;
state->cplco[i][j] =
cplcomant * scale_factor[cplcoexp + mstrcplco];
}
}
if ((state->acmod == 2) && state->phsflginu && cplcoe)
for (j = 0; j < state->ncplbnd; j++)
if (bitstream_get (1)) /* phsflg */
state->cplco[1][j] = -state->cplco[1][j];
}
if ((state->acmod == 2) && (bitstream_get (1))) { /* rematstr */
int end;
state->rematflg = 0;
end = (state->chincpl) ? state->cplstrtmant : 253; /* cplinu */
i = 0;
do
state->rematflg |= bitstream_get (1) << i;
while (rematrix_band[i++] < end);
}
cplexpstr = EXP_REUSE;
lfeexpstr = EXP_REUSE;
if (state->chincpl) /* cplinu */
cplexpstr = bitstream_get (2);
for (i = 0; i < nfchans; i++)
chexpstr[i] = bitstream_get (2);
if (state->lfeon)
lfeexpstr = bitstream_get (1);
for (i = 0; i < nfchans; i++)
if (chexpstr[i] != EXP_REUSE) {
if ((state->chincpl >> i) & 1)
state->endmant[i] = state->cplstrtmant;
else {
int chbwcod;
chbwcod = bitstream_get (6);
if (chbwcod > 60)
return 1;
state->endmant[i] = chbwcod * 3 + 73;
}
}
do_bit_alloc = 0;
if (cplexpstr != EXP_REUSE) {
int cplabsexp, ncplgrps;
do_bit_alloc = 64;
ncplgrps = ((state->cplendmant - state->cplstrtmant) /
(3 << (cplexpstr - 1)));
cplabsexp = bitstream_get (4) << 1;
if (parse_exponents (cplexpstr, ncplgrps, cplabsexp,
state->cpl_expbap.exp + state->cplstrtmant))
return 1;
}
for (i = 0; i < nfchans; i++)
if (chexpstr[i] != EXP_REUSE) {
int grp_size, nchgrps;
do_bit_alloc |= 1 << i;
grp_size = 3 << (chexpstr[i] - 1);
nchgrps = (state->endmant[i] + grp_size - 4) / grp_size;
state->fbw_expbap[i].exp[0] = bitstream_get (4);
if (parse_exponents (chexpstr[i], nchgrps,
state->fbw_expbap[i].exp[0],
state->fbw_expbap[i].exp + 1))
return 1;
bitstream_get (2); /* gainrng */
}
if (lfeexpstr != EXP_REUSE) {
do_bit_alloc |= 32;
state->lfe_expbap.exp[0] = bitstream_get (4);
if (parse_exponents (lfeexpstr, 2, state->lfe_expbap.exp[0],
state->lfe_expbap.exp + 1))
return 1;
}
if (bitstream_get (1)) { /* baie */
do_bit_alloc = -1;
state->bai = bitstream_get (11);
}
if (bitstream_get (1)) { /* snroffste */
do_bit_alloc = -1;
state->csnroffst = bitstream_get (6);
if (state->chincpl) /* cplinu */
state->cplba.bai = bitstream_get (7);
for (i = 0; i < nfchans; i++)
state->ba[i].bai = bitstream_get (7);
if (state->lfeon)
state->lfeba.bai = bitstream_get (7);
}
if ((state->chincpl) && (bitstream_get (1))) { /* cplinu, cplleake */
do_bit_alloc |= 64;
state->cplfleak = 9 - bitstream_get (3);
state->cplsleak = 9 - bitstream_get (3);
}
if (bitstream_get (1)) { /* deltbaie */
do_bit_alloc = -1;
if (state->chincpl) /* cplinu */
state->cplba.deltbae = bitstream_get (2);
for (i = 0; i < nfchans; i++)
state->ba[i].deltbae = bitstream_get (2);
if (state->chincpl && /* cplinu */
(state->cplba.deltbae == DELTA_BIT_NEW) &&
parse_deltba (state->cplba.deltba))
return 1;
for (i = 0; i < nfchans; i++)
if ((state->ba[i].deltbae == DELTA_BIT_NEW) &&
parse_deltba (state->ba[i].deltba))
return 1;
}
if (do_bit_alloc) {
if (zero_snr_offsets (nfchans, state)) {
memset (state->cpl_expbap.bap, 0, sizeof (state->cpl_expbap.bap));
for (i = 0; i < nfchans; i++)
memset (state->fbw_expbap[i].bap, 0,
sizeof (state->fbw_expbap[i].bap));
memset (state->lfe_expbap.bap, 0, sizeof (state->lfe_expbap.bap));
} else {
if (state->chincpl && (do_bit_alloc & 64)) /* cplinu */
a52_bit_allocate (state, &state->cplba, state->cplstrtbnd,
state->cplstrtmant, state->cplendmant,
state->cplfleak << 8, state->cplsleak << 8,
&state->cpl_expbap);
for (i = 0; i < nfchans; i++)
if (do_bit_alloc & (1 << i))
a52_bit_allocate (state, state->ba + i, 0, 0,
state->endmant[i], 0, 0,
state->fbw_expbap +i);
if (state->lfeon && (do_bit_alloc & 32)) {
state->lfeba.deltbae = DELTA_BIT_NONE;
a52_bit_allocate (state, &state->lfeba, 0, 0, 7, 0, 0,
&state->lfe_expbap);
}
}
}
if (bitstream_get (1)) { /* skiple */
i = bitstream_get (9); /* skipl */
while (i--)
bitstream_get (8);
}
samples = state->samples;
if (state->output & A52_LFE)
samples += 256; /* shift for LFE channel */
chanbias = a52_downmix_coeff (coeff, state->acmod, state->output,
state->dynrng, state->clev, state->slev);
quantizer.q1_ptr = quantizer.q2_ptr = quantizer.q4_ptr = -1;
done_cpl = 0;
for (i = 0; i < nfchans; i++) {
int j;
coeff_get (samples + 256 * i, state->fbw_expbap +i, &quantizer,
coeff[i], dithflag[i], state->endmant[i]);
if ((state->chincpl >> i) & 1) {
if (!done_cpl) {
done_cpl = 1;
coeff_get_coupling (state, nfchans, coeff,
(sample_t (*)[256])samples, &quantizer,
dithflag);
}
j = state->cplendmant;
} else
j = state->endmant[i];
do
(samples + 256 * i)[j] = 0;
while (++j < 256);
}
if (state->acmod == 2) {
int j, end, band, rematflg;
end = ((state->endmant[0] < state->endmant[1]) ?
state->endmant[0] : state->endmant[1]);
i = 0;
j = 13;
rematflg = state->rematflg;
do {
if (! (rematflg & 1)) {
rematflg >>= 1;
j = rematrix_band[i++];
continue;
}
rematflg >>= 1;
band = rematrix_band[i++];
if (band > end)
band = end;
do {
sample_t tmp0, tmp1;
tmp0 = samples[j];
tmp1 = (samples+256)[j];
samples[j] = tmp0 + tmp1;
(samples+256)[j] = tmp0 - tmp1;
} while (++j < band);
} while (j < end);
}
if (state->lfeon) {
if (state->output & A52_LFE) {
coeff_get (samples - 256, &state->lfe_expbap, &quantizer,
state->dynrng, 0, 7);
for (i = 7; i < 256; i++)
(samples-256)[i] = 0;
a52_imdct_512 (samples - 256, samples + 1536 - 256, state->bias);
} else {
/* just skip the LFE coefficients */
coeff_get (samples + 1280, &state->lfe_expbap, &quantizer,
0, 0, 7);
}
}
i = 0;
if (nfchans_tbl[state->output & A52_CHANNEL_MASK] < nfchans)
for (i = 1; i < nfchans; i++)
if (blksw[i] != blksw[0])
break;
if (i < nfchans) {
if (state->downmixed) {
state->downmixed = 0;
a52_upmix (samples + 1536, state->acmod, state->output);
}
for (i = 0; i < nfchans; i++) {
sample_t bias;
bias = 0;
if (!(chanbias & (1 << i)))
bias = state->bias;
if (coeff[i]) {
if (blksw[i])
a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
bias);
else
a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
bias);
} else {
int j;
for (j = 0; j < 256; j++)
(samples + 256 * i)[j] = bias;
}
}
a52_downmix (samples, state->acmod, state->output, state->bias,
state->clev, state->slev);
} else {
nfchans = nfchans_tbl[state->output & A52_CHANNEL_MASK];
a52_downmix (samples, state->acmod, state->output, 0,
state->clev, state->slev);
if (!state->downmixed) {
state->downmixed = 1;
a52_downmix (samples + 1536, state->acmod, state->output, 0,
state->clev, state->slev);
}
if (blksw[0])
for (i = 0; i < nfchans; i++)
a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
state->bias);
else
for (i = 0; i < nfchans; i++)
a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
state->bias);
}
return 0;
}
void a52_free (a52_state_t * state)
{
free (state->samples);
free (state);
}
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