void __stdcall ac3_init(ac3_state *state)
{
state->frame_count=0;
bitstream_init(state);
imdct_init();
sanity_check_init(&state->syncinfo,&state->bsi,&state->audblk);
}
void InitialAC3()
{
error_flag = buffer_size = 0;
ZeroMemory(&syncinfo, sizeof(syncinfo));
ZeroMemory(&bsi, sizeof(bsi));
ZeroMemory(&audblk, sizeof(audblk));
drc_init();
imdct_init();
exponent_init();
mantissa_init();
srand(0);
}
/*=============================================================*/
int L3table_init(MPEG *m)
{
int i;
float *x;
LS *ls;
int scalefact_scale, preemp, scalefac;
double tmp;
PAIR *csa;
/*================ quant ===============================*/
/* 8 bit plus 2 lookup x = pow(2.0, 0.25*(global_gain-210)) */
/* extra 2 for ms scaling by 1/sqrt(2) */
/* extra 4 for cvt to mono scaling by 1/2 */
x = quant_init_global_addr(m);
for (i = 0; i < 256 + 2 + 4; i++)
x[i] = (float) pow(2.0, 0.25 * ((i - (2 + 4)) - 210 + GLOBAL_GAIN_SCALE));
/* x = pow(2.0, -0.5*(1+scalefact_scale)*scalefac + preemp) */
ls = quant_init_scale_addr(m);
for (scalefact_scale = 0; scalefact_scale < 2; scalefact_scale++)
{
for (preemp = 0; preemp < 4; preemp++)
{
for (scalefac = 0; scalefac < 32; scalefac++)
{
ls[scalefact_scale][preemp][scalefac] =
(float) pow(2.0, -0.5 * (1 + scalefact_scale) * (scalefac + preemp));
}
}
}
/*--- iSample**(4/3) lookup, -32<=i<=31 ---*/
x = quant_init_pow_addr(m);
for (i = 0; i < 64; i++)
{
tmp = i - 32;
x[i] = (float) (tmp * pow(fabs(tmp), (1.0 / 3.0)));
}
/*-- pow(2.0, -0.25*8.0*subblock_gain) 3 bits --*/
x = quant_init_subblock_addr(m);
for (i = 0; i < 8; i++)
{
x[i] = (float) pow(2.0, 0.25 * -8.0 * i);
}
/*-------------------------*/
// quant_init_sf_band(sr_index); replaced by code in sup.c
/*================ antialias ===============================*/
csa = alias_init_addr(m);
for (i = 0; i < 8; i++)
{
csa[i][0] = (float) (1.0 / sqrt(1.0 + Ci[i] * Ci[i]));
csa[i][1] = (float) (Ci[i] / sqrt(1.0 + Ci[i] * Ci[i]));
}
/*================ msis ===============================*/
msis_init(m);
msis_init_MPEG2(m);
/*================ imdct ===============================*/
imdct_init(m);
/*--- hybrid windows ------------*/
hwin_init(m);
return 0;
}
int AC3_SampleConvert(sint_16 *pPcmData, uint_32 *pnPcmDataLen, uint_8* pAc3Buf, uint_32 nAc3DataLen)
{
int i;
bitstream_t *bs;
long SampleRate = 0; /* bitstream sample-rate */
uint_32 cbErrors = 0; /* bitstream error count returned by decode_sanity_check() */
uint_32 cbMantErrors, cbExpErrors; /* error counters for mantissa & exponent unpacking errors */
bsi_t bsi_blank = {0};
static audblk_t audblk_blank = {0};
bs = bitstream_open(pAc3Buf, pAc3Buf+nAc3DataLen);
imdct_init();
/* initialize decoder and counter variables */
(bsi) = bsi_blank;
(audblk) = audblk_blank;
decode_sanity_check_init();
bsi_blank = bsi;
audblk_blank = audblk;
cbErrors = 0;
audblk = audblk_blank; /* clear out audioblock */
if(!(decode_resync(bs)))
{
return 0;
}
bsi = bsi_blank; /* v0.04 wipe bsi clear, not really necessary */
parse_syncinfo(&syncinfo,bs);
parse_bsi(&bsi,bs);
switch (syncinfo.fscod)
{
case 2:
SampleRate = 32000;
break;
case 1:
SampleRate = 44100;
break;
case 0:
SampleRate = 48000;
break;
default:
return 0;
}
/* reset bitstream error counters */
cbErrors =
cbExpErrors =
cbMantErrors = 0;
memset(pPcmData, 0, BUFFER_SIZE1*2);
*pnPcmDataLen = 0;
for(i=0; i < 6; i++)
{
long buf_offset;
parse_audblk(&bsi,&audblk,bs,i); // CPU time 10%
cbExpErrors = exponent_unpack(&bsi,&audblk);
if(cbExpErrors > 0)
{
return 0;
cbExpErrors =0;
}
bit_allocate(syncinfo.fscod,&bsi,&audblk); // CPU TIME 1.2%
if ( bsi.nfchans > 6 )
{
bsi.nfchans = 0;
return 0;//(LPBYTE) out_buf;
}
cbMantErrors = mantissa_unpack(&bsi,&audblk,bs); // CPU TIME 62.0%
if( cbMantErrors > 0)
{
return 0;
cbMantErrors = 0;
}
uncouple(&bsi,&audblk,&stream_coeffs); // CPU TIME 1.7%
if(bsi.acmod == 0x2)
rematrix(&audblk,&stream_coeffs); // CPU TIME 0.1%
imdct(&bsi,&audblk,&stream_coeffs,&stream_samples); // CPU TIME 11.2%
buf_offset = i * 512;
downmix( &stream_samples, pPcmData+buf_offset, &bsi, 0 );
} /* endfor ( i = 0 ... ) */
*pnPcmDataLen = 6*512*2;
cbErrors = decode_sanity_check();
if(cbErrors > 0)
{
return 0;
}
parse_auxdata(&syncinfo,bs); // CPU TIME 2.0%
if(!crc_validate())
{
return 0;
}
return 1;
}
/* call this once at the beginning
*/
void initialise_decoder(void)
{
premultiply();
imdct_init();
calculate_t43();
}
