RepoMirrors
/
ffmpeg
mirror of https://git.ffmpeg.org/ffmpeg.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
ffmpeg/libavcodec/libac3/parse.c

683 lines
16 KiB
C
Raw Blame History

/*
* parse.c
*
* Copyright (C) Aaron Holtzman - May 1999
*
* This file is part of ac3dec, a free Dolby AC-3 stream decoder.
*
* ac3dec 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, or (at your option)
* any later version.
*
* ac3dec 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 GNU Make; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
*/
#include "../common.h"
#include "ac3.h"
#include "ac3_internal.h"
#include "bitstream.h"
#include "tables.h"
extern stream_samples_t samples; // FIXME
static float delay[6][256];
void ac3_init (void)
{
imdct_init ();
}
static uint8_t halfrate[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3};
int ac3_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) ? AC3_DOLBY : acmod) |
((buf[6] & lfeon[acmod]) ? AC3_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: // 48 KHz
*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 ac3_frame (ac3_state_t * state, uint8_t * buf, int * flags, float * level,
float bias)
{
static float clev[4] = {LEVEL_3DB, LEVEL_45DB, LEVEL_6DB, LEVEL_45DB};
static float 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;
bitstream_set_ptr (buf + 6);
bitstream_get (3); // skip acmod we already parsed
if ((acmod == 2) && (bitstream_get (2) == 2)) // dsurmod
acmod = AC3_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 = downmix_init (acmod, *flags, level,
state->clev, state->slev);
if (state->output < 0)
return 1;
*flags = state->output;
state->level = *level;
state->bias = bias;
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;
}
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, ac3_state_t * state)
{
int i;
if ((state->csnroffst) || (state->cplinu && state->cplba.fsnroffst) ||
(state->lfeon && state->lfeba.fsnroffst))
return 0;
for (i = 0; i < nfchans; i++)
if (state->ba[i].fsnroffst)
return 0;
return 1;
}
static float q_1[2];
static float q_2[2];
static float q_4;
static int q_1_pointer;
static int q_2_pointer;
static int q_4_pointer;
#define GET_COEFF(COEFF,DITHER) \
switch (bap[i]) { \
case 0: \
DITHER (scale_factor[exp[i]]); \
\
case -1: \
if (q_1_pointer >= 0) { \
COEFF (q_1[q_1_pointer--] * scale_factor[exp[i]]); \
} else { \
int code; \
\
code = bitstream_get (5); \
\
q_1_pointer = 1; \
q_1[0] = q_1_2[code]; \
q_1[1] = q_1_1[code]; \
COEFF (q_1_0[code] * scale_factor[exp[i]]); \
} \
\
case -2: \
if (q_2_pointer >= 0) { \
COEFF (q_2[q_2_pointer--] * scale_factor[exp[i]]); \
} else { \
int code; \
\
code = bitstream_get (7); \
\
q_2_pointer = 1; \
q_2[0] = q_2_2[code]; \
q_2[1] = q_2_1[code]; \
COEFF (q_2_0[code] * scale_factor[exp[i]]); \
} \
\
case 3: \
COEFF (q_3[bitstream_get (3)] * scale_factor[exp[i]]); \
\
case -3: \
if (q_4_pointer == 0) { \
q_4_pointer = -1; \
COEFF (q_4 * scale_factor[exp[i]]); \
} else { \
int code; \
\
code = bitstream_get (7); \
\
q_4_pointer = 0; \
q_4 = q_4_1[code]; \
COEFF (q_4_0[code] * scale_factor[exp[i]]); \
} \
\
case 4: \
COEFF (q_5[bitstream_get (4)] * scale_factor[exp[i]]); \
\
default: \
COEFF (((int16_t)(bitstream_get(bap[i]) << (16 - bap[i]))) * \
scale_factor[exp[i]]); \
}
#define CHANNEL_COEFF(val) \
coeff[i++] = val; \
continue;
#define CHANNEL_DITHER(val) \
if (dither) { \
coeff[i++] = dither_gen () * val; \
continue; \
} else { \
coeff[i++] = 0; \
continue; \
}
static uint16_t lfsr_state = 1;
static inline int16_t dither_gen(void)
{
int16_t state;
state = dither_lut[lfsr_state >> 8] ^ (lfsr_state << 8);
lfsr_state = (uint16_t) state;
return ((state * (int) (LEVEL_3DB * 256)) >> 8);
}
static void coeff_get (float * coeff, uint8_t * exp, int8_t * bap,
int dither, int end)
{
int i;
i = 0;
while (i < end)
GET_COEFF (CHANNEL_COEFF, CHANNEL_DITHER);
}
#define COUPLING_COEFF(val) \
cplcoeff = val; \
break;
#define COUPLING_DITHER(val) \
cplcoeff = val; \
for (ch = 0; ch < nfchans; ch++) \
if (state->chincpl[ch]) { \
if (dithflag[ch]) \
samples[ch][i] = \
state->cplco[ch][bnd] * dither_gen () * cplcoeff; \
else \
samples[ch][i] = 0; \
} \
i++; \
continue;
int ac3_block (ac3_state_t * state)
{
static const uint8_t nfchans_tbl[8] = {2, 1, 2, 3, 3, 4, 4, 5};
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];
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
bitstream_get (8); // dynrng
} while (chaninfo--);
if (bitstream_get (1)) { // cplstre
state->cplinu = bitstream_get (1);
if (state->cplinu) {
static int 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[i] = bitstream_get (1);
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;
for (i = 0; i < ncplsubnd - 1; i++) {
state->cplbndstrc[i] = bitstream_get (1);
state->ncplbnd -= state->cplbndstrc[i];
}
state->cplbndstrc[i] = 0; // last value is a sentinel
}
}
if (state->cplinu) {
int j, cplcoe;
cplcoe = 0;
for (i = 0; i < nfchans; i++)
if (state->chincpl[i])
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;
end = (state->cplinu) ? state->cplstrtmant : 253;
i = 0;
do
state->rematflg[i] = bitstream_get (1);
while (rematrix_band[i++] < end);
}
cplexpstr = EXP_REUSE;
lfeexpstr = EXP_REUSE;
if (state->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->cplinu && state->chincpl[i])
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 = 1;
ncplgrps = ((state->cplendmant - state->cplstrtmant) /
(3 << (cplexpstr - 1)));
cplabsexp = bitstream_get (4) << 1;
if (parse_exponents (cplexpstr, ncplgrps, cplabsexp,
state->cpl_exp + state->cplstrtmant))
return 1;
}
for (i = 0; i < nfchans; i++)
if (chexpstr[i] != EXP_REUSE) {
int grp_size, nchgrps;
do_bit_alloc = 1;
grp_size = 3 << (chexpstr[i] - 1);
nchgrps = (state->endmant[i] + grp_size - 4) / grp_size;
state->fbw_exp[i][0] = bitstream_get (4);
if (parse_exponents (chexpstr[i], nchgrps, state->fbw_exp[i][0],
state->fbw_exp[i] + 1))
return 1;
bitstream_get (2); // gainrng
}
if (lfeexpstr != EXP_REUSE) {
do_bit_alloc = 1;
state->lfe_exp[0] = bitstream_get (4);
if (parse_exponents (lfeexpstr, 2, state->lfe_exp[0],
state->lfe_exp + 1))
return 1;
}
if (bitstream_get (1)) { // baie
do_bit_alloc = 1;
state->sdcycod = bitstream_get (2);
state->fdcycod = bitstream_get (2);
state->sgaincod = bitstream_get (2);
state->dbpbcod = bitstream_get (2);
state->floorcod = bitstream_get (3);
}
if (bitstream_get (1)) { //snroffste
do_bit_alloc = 1;
state->csnroffst = bitstream_get (6);
if (state->cplinu) {
state->cplba.fsnroffst = bitstream_get (4);
state->cplba.fgaincod = bitstream_get (3);
}
for (i = 0; i < nfchans; i++) {
state->ba[i].fsnroffst = bitstream_get (4);
state->ba[i].fgaincod = bitstream_get (3);
}
if (state->lfeon) {
state->lfeba.fsnroffst = bitstream_get (4);
state->lfeba.fgaincod = bitstream_get (3);
}
}
if ((state->cplinu) && (bitstream_get (1))) { // cplleake
do_bit_alloc = 1;
state->cplfleak = 2304 - (bitstream_get (3) << 8);
state->cplsleak = 2304 - (bitstream_get (3) << 8);
}
if (bitstream_get (1)) { // deltbaie
do_bit_alloc = 1;
if (state->cplinu)
state->cplba.deltbae = bitstream_get (2);
for (i = 0; i < nfchans; i++)
state->ba[i].deltbae = bitstream_get (2);
if (state->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_bap, 0, sizeof (state->cpl_bap));
memset (state->fbw_bap, 0, sizeof (state->fbw_bap));
memset (state->lfe_bap, 0, sizeof (state->lfe_bap));
} else {
if (state->cplinu)
bit_allocate (state, &state->cplba, state->cplstrtbnd,
state->cplstrtmant, state->cplendmant,
state->cplfleak, state->cplsleak,
state->cpl_exp, state->cpl_bap);
for (i = 0; i < nfchans; i++)
bit_allocate (state, state->ba + i, 0, 0, state->endmant[i],
0, 0, state->fbw_exp[i], state->fbw_bap[i]);
if (state->lfeon) {
state->lfeba.deltbae = DELTA_BIT_NONE;
bit_allocate (state, &state->lfeba, 0, 0, 7, 0, 0,
state->lfe_exp, state->lfe_bap);
}
}
}
if (bitstream_get (1)) { // skiple
i = bitstream_get (9); // skipl
while (i--)
bitstream_get (8);
}
q_1_pointer = q_2_pointer = q_4_pointer = -1;
done_cpl = 0;
for (i = 0; i < nfchans; i++) {
int j;
coeff_get (samples[i], state->fbw_exp[i], state->fbw_bap[i],
dithflag[i], state->endmant[i]);
if (state->cplinu && state->chincpl[i]) {
if (!done_cpl) {
int i, i_end, bnd, sub_bnd, ch;
float cplcoeff;
done_cpl = 1;
#define bap state->cpl_bap
#define exp state->cpl_exp
sub_bnd = bnd = 0;
i = state->cplstrtmant;
while (i < state->cplendmant) {
i_end = i + 12;
while (state->cplbndstrc[sub_bnd++])
i_end += 12;
while (i < i_end) {
GET_COEFF (COUPLING_COEFF, COUPLING_DITHER);
for (ch = 0; ch < nfchans; ch++)
if (state->chincpl[ch])
samples[ch][i] =
state->cplco[ch][bnd] * cplcoeff;
i++;
}
bnd++;
}
#undef bap
#undef exp
}
j = state->cplendmant;
} else
j = state->endmant[i];
for (; j < 256; j++)
samples[i][j] = 0;
}
if (state->acmod == 2) {
int j, end, band;
end = ((state->endmant[0] < state->endmant[1]) ?
state->endmant[0] : state->endmant[1]);
i = 0;
j = 13;
do {
if (!state->rematflg[i]) {
j = rematrix_band[i++];
continue;
}
band = rematrix_band[i++];
if (band > end)
band = end;
do {
float tmp0, tmp1;
tmp0 = samples[0][j];
tmp1 = samples[1][j];
samples[0][j] = tmp0 + tmp1;
samples[1][j] = tmp0 - tmp1;
} while (++j < band);
} while (j < end);
}
if (state->lfeon) {
coeff_get (samples[5], state->lfe_exp, state->lfe_bap, 0, 7);
#if 0
for (i = 7; i < 256; i++)
samples[5][i] = 0;
#endif
}
for (i = 0; i < nfchans; i++)
if (blksw[i])
imdct_256 (samples[i], delay[i]);
else
imdct_512 (samples[i], delay[i]);
#if 0
if (state->lfeon)
imdct_512 (samples[5], delay[5]);
#endif
downmix (*samples, state->acmod, state->output, state->level, state->bias,
state->clev, state->slev);
return 0;
}
Reference in New Issue View Git Blame Copy Permalink