?? decode.c
字號(hào):
}
}
i = 0;
while ( sfBandIndex[sfreq].l[i] <= sb )
i++;
sfb = i;
i = sfBandIndex[sfreq].l[i];
for ( ; sfb<8; sfb++ )
{ sb = sfBandIndex[sfreq].l[sfb+1]-sfBandIndex[sfreq].l[sfb];
for ( ; sb > 0; sb--)
{ is_pos[i] = (*scalefac)[1].l[sfb];
if ( is_pos[i] != 7 )
is_ratio[i] = tan( is_pos[i] * (PI / 12));
i++;
}
}
}
} else
{ for ( j=0; j<3; j++ )
{ int sfbcnt;
sfbcnt = -1;
for( sfb=12; sfb >=0; sfb-- )
{ int lines;
lines = sfBandIndex[sfreq].s[sfb+1]-sfBandIndex[sfreq].s[sfb];
i = 3*sfBandIndex[sfreq].s[sfb] + (j+1) * lines - 1;
while ( lines > 0 )
{ if ( xr[1][i/SSLIMIT][i%SSLIMIT] != 0.0 )
{ sfbcnt = sfb;
sfb = -10;
lines = -10;
}
lines--;
i--;
}
}
sfb = sfbcnt + 1;
while( sfb<12 )
{ sb = sfBandIndex[sfreq].s[sfb+1]-sfBandIndex[sfreq].s[sfb];
i = 3*sfBandIndex[sfreq].s[sfb] + j * sb;
for ( ; sb > 0; sb--)
{ is_pos[i] = (*scalefac)[1].s[j][sfb];
if ( is_pos[i] != 7 )
is_ratio[i] = tan( is_pos[i] * (PI / 12));
i++;
}
sfb++;
}
sb = sfBandIndex[sfreq].s[11]-sfBandIndex[sfreq].s[10];
sfb = 3*sfBandIndex[sfreq].s[10] + j * sb;
sb = sfBandIndex[sfreq].s[12]-sfBandIndex[sfreq].s[11];
i = 3*sfBandIndex[sfreq].s[11] + j * sb;
for ( ; sb > 0; sb-- )
{ is_pos[i] = is_pos[sfb];
is_ratio[i] = is_ratio[sfb];
i++;
}
}
}
} else
{ i = 31;
ss = 17;
sb = 0;
while ( i >= 0 )
{ if ( xr[1][i][ss] != 0.0 )
{ sb = i*18+ss;
i = -1;
} else
{ ss--;
if ( ss < 0 )
{ i--;
ss = 17;
}
}
}
i = 0;
while ( sfBandIndex[sfreq].l[i] <= sb )
i++;
sfb = i;
i = sfBandIndex[sfreq].l[i];
for ( ; sfb<21; sfb++ )
{ sb = sfBandIndex[sfreq].l[sfb+1] - sfBandIndex[sfreq].l[sfb];
for ( ; sb > 0; sb--)
{ is_pos[i] = (*scalefac)[1].l[sfb];
if ( is_pos[i] != 7 )
is_ratio[i] = tan( is_pos[i] * (PI / 12));
i++;
}
}
sfb = sfBandIndex[sfreq].l[20];
for ( sb = 576 - sfBandIndex[sfreq].l[21]; sb > 0; sb-- )
{ is_pos[i] = is_pos[sfb];
is_ratio[i] = is_ratio[sfb];
i++;
}
}
}
for(ch=0;ch<2;ch++)
for(sb=0;sb<SBLIMIT;sb++)
for(ss=0;ss<SSLIMIT;ss++)
lr[ch][sb][ss] = 0;
if (stereo==2)
for(sb=0;sb<SBLIMIT;sb++)
for(ss=0;ss<SSLIMIT;ss++) {
i = (sb*18)+ss;
if ( is_pos[i] == 7 ) {
if ( ms_stereo ) {
lr[0][sb][ss] = (xr[0][sb][ss]+xr[1][sb][ss])/1.41421356;
lr[1][sb][ss] = (xr[0][sb][ss]-xr[1][sb][ss])/1.41421356;
}
else {
lr[0][sb][ss] = xr[0][sb][ss];
lr[1][sb][ss] = xr[1][sb][ss];
}
}
else if (i_stereo ) {
lr[0][sb][ss] = xr[0][sb][ss] * (is_ratio[i]/(1+is_ratio[i]));
lr[1][sb][ss] = xr[0][sb][ss] * (1/(1+is_ratio[i]));
}
else {
printf("Error in streo processing\n");
}
}
else /* mono , bypass xr[0][][] to lr[0][][]*/
for(sb=0;sb<SBLIMIT;sb++)
for(ss=0;ss<SSLIMIT;ss++)
lr[0][sb][ss] = xr[0][sb][ss];
}
double Ci[8]={-0.6,-0.535,-0.33,-0.185,-0.095,-0.041,-0.0142,-0.0037};
void III_antialias(double xr[SBLIMIT][SSLIMIT], double hybridIn[SBLIMIT][SSLIMIT], struct gr_info_s *gr_info, frame_params *fr_ps)
{
static int init = 1;
static double ca[8],cs[8];
double bu,bd; /* upper and lower butterfly inputs */
int ss,sb,sblim;
if (init) {
int i;
double sq;
for (i=0;i<8;i++) {
sq=sqrt(1.0+Ci[i]*Ci[i]);
cs[i] = 1.0/sq;
ca[i] = Ci[i]/sq;
}
init = 0;
}
/* clear all inputs */
for(sb=0;sb<SBLIMIT;sb++)
for(ss=0;ss<SSLIMIT;ss++)
hybridIn[sb][ss] = xr[sb][ss];
if (gr_info->window_switching_flag && (gr_info->block_type == 2) &&
!gr_info->mixed_block_flag ) return;
if ( gr_info->window_switching_flag && gr_info->mixed_block_flag &&
(gr_info->block_type == 2))
sblim = 1;
else
sblim = SBLIMIT-1;
/* 31 alias-reduction operations between each pair of sub-bands */
/* with 8 butterflies between each pair */
for(sb=0;sb<sblim;sb++)
for(ss=0;ss<8;ss++) {
bu = xr[sb][17-ss];
bd = xr[sb+1][ss];
hybridIn[sb][17-ss] = (bu * cs[ss]) - (bd * ca[ss]);
hybridIn[sb+1][ss] = (bd * cs[ss]) + (bu * ca[ss]);
}
}
/*------------------------------------------------------------------*/
/* */
/* Function: Calculation of the inverse MDCT */
/* In the case of short blocks the 3 output vectors are already */
/* overlapped and added in this modul. */
/* */
/* New layer3 */
/* */
/*------------------------------------------------------------------*/
void inv_mdct(double in[18], double out[36], int block_type)
{
int i,m,N,p;
double tmp[12],sum;
static double win[4][36];
static int init=0;
static double COS[4*36];
if(init==0){
/* type 0 */
for(i=0;i<36;i++)
win[0][i] = sin( PI/36 *(i+0.5) );
/* type 1*/
for(i=0;i<18;i++)
win[1][i] = sin( PI/36 *(i+0.5) );
for(i=18;i<24;i++)
win[1][i] = 1.0;
for(i=24;i<30;i++)
win[1][i] = sin( PI/12 *(i+0.5-18) );
for(i=30;i<36;i++)
win[1][i] = 0.0;
/* type 3*/
for(i=0;i<6;i++)
win[3][i] = 0.0;
for(i=6;i<12;i++)
win[3][i] = sin( PI/12 *(i+0.5-6) );
for(i=12;i<18;i++)
win[3][i] =1.0;
for(i=18;i<36;i++)
win[3][i] = sin( PI/36*(i+0.5) );
/* type 2*/
for(i=0;i<12;i++)
win[2][i] = sin( PI/12*(i+0.5) ) ;
for(i=12;i<36;i++)
win[2][i] = 0.0 ;
for (i=0; i<4*36; i++)
COS[i] = cos(PI/(2*36) * i);
init++;
}
for(i=0;i<36;i++)
out[i]=0;
if(block_type == 2){
N=12;
for(i=0;i<3;i++){
for(p= 0;p<N;p++){
sum = 0.0;
for(m=0;m<N/2;m++)
sum += in[i+3*m] * cos( PI/(2*N)*(2*p+1+N/2)*(2*m+1) );
tmp[p] = sum * win[block_type][p] ;
}
for(p=0;p<N;p++)
out[6*i+p+6] += tmp[p];
}
}
else{
N=36;
for(p= 0;p<N;p++){
sum = 0.0;
for(m=0;m<N/2;m++)
sum += in[m] * COS[((2*p+1+N/2)*(2*m+1))%(4*36)];
out[p] = sum * win[block_type][p];
}
}
}
void III_hybrid(double fsIn[SSLIMIT], double tsOut[SSLIMIT], int sb, int ch, struct gr_info_s *gr_info, frame_params *fr_ps)
/* fsIn:freq samples per subband in */
/* tsOut:time samples per subband out */
{
int ss;
double rawout[36];
static double prevblck[2][SBLIMIT][SSLIMIT];
static int init = 1;
int bt;
if (init) {
int i,j,k;
for(i=0;i<2;i++)
for(j=0;j<SBLIMIT;j++)
for(k=0;k<SSLIMIT;k++)
prevblck[i][j][k]=0.0;
init = 0;
}
bt = (gr_info->window_switching_flag && gr_info->mixed_block_flag &&
(sb < 2)) ? 0 : gr_info->block_type;
inv_mdct( fsIn, rawout, bt);
/* overlap addition */
for(ss=0; ss<SSLIMIT; ss++) {
tsOut[ss] = rawout[ss] + prevblck[ch][sb][ss];
prevblck[ch][sb][ss] = rawout[ss+18];
}
}
/*************************************************************
/*
/* Pass the subband sample through the synthesis window
/*
/**************************************************************/
/* create in synthesis filter */
void create_syn_filter(double filter[64][SBLIMIT])
{
register int i,k;
for (i=0; i<64; i++)
for (k=0; k<32; k++) {
if ((filter[i][k] = 1e9*cos((double)((PI64*i+PI4)*(2*k+1)))) >= 0)
modf(filter[i][k]+0.5, &filter[i][k]);
else
modf(filter[i][k]-0.5, &filter[i][k]);
filter[i][k] *= 1e-9;
}
}
/***************************************************************
/*
/* Window the restored sample
/*
/***************************************************************/
/* read in synthesis window */
void read_syn_window(double window[HAN_SIZE])
{
int i,j[4];
FILE *fp;
double f[4];
char t[150];
if (!(fp = OpenTableFile("dewindow.txt") )) {
printf("Please check synthesis window table 'dewindow.txt'\n");
exit(1);
}
for (i=0;i<512;i+=4) {
fgets(t, 150, fp);
sscanf(t,"D[%d] = %lf D[%d] = %lf D[%d] = %lf D[%d] = %lf\n",
j, f,j+1,f+1,j+2,f+2,j+3,f+3);
if (i==j[0]) {
window[i] = f[0];
window[i+1] = f[1];
window[i+2] = f[2];
window[i+3] = f[3];
}
else {
printf("Check index in synthesis window table\n");
exit(1);
}
fgets(t,150,fp);
}
fclose(fp);
}
int SubBandSynthesis (double *bandPtr, int channel, short *samples)
{
register int i,j,k;
register double *bufOffsetPtr, sum;
static int init = 1;
typedef double NN[64][32];
static NN *filter;
typedef double BB[2][2*HAN_SIZE];
static BB *buf;
static int bufOffset[2] = {64,64};
static double *window;
int clip = 0; /* count & return how many samples clipped */
if (init) {
buf = (BB *) mem_alloc(sizeof(BB),"BB");
filter = (NN *) mem_alloc(sizeof(NN), "NN");
create_syn_filter(*filter);
window = (double *) mem_alloc(sizeof(double) * HAN_SIZE, "WIN");
read_syn_window(window);
init = 0;
}
/* if (channel == 0) */
bufOffset[channel] = (bufOffset[channel] - 64) & 0x3ff;
bufOffsetPtr = &((*buf)[channel][bufOffset[channel]]);
for (i=0; i<64; i++) {
sum = 0;
for (k=0; k<32; k++)
sum += bandPtr[k] * (*filter)[i][k];
bufOffsetPtr[i] = sum;
}
/* S(i,j) = D(j+32i) * U(j+32i+((i+1)>>1)*64) */
/* samples(i,j) = MWindow(j+32i) * bufPtr(j+32i+((i+1)>>1)*64) */
for (j=0; j<32; j++) {
sum = 0;
for (i=0; i<16; i++) {
k = j + (i<<5);
sum += window[k] * (*buf) [channel] [( (k + ( ((i+1)>>1) <<6) ) +
bufOffset[channel]) & 0x3ff];
}
{
/*long foo = (sum > 0) ? sum * SCALE + 0.5 : sum * SCALE - 0.5; */
long foo = sum * SCALE;
if (foo >= (long) SCALE) {samples[j] = SCALE-1; ++clip;}
else if (foo < (long) -SCALE) {samples[j] = -SCALE; ++clip;}
else samples[j] = foo;
}
}
return(clip);
}
void out_fifo(short pcm_sample[2][SSLIMIT][SBLIMIT], int num, frame_params *fr_ps, int done, FILE *outFile, unsigned long *psampFrames)
{
int i,j,l;
int stereo = fr_ps->stereo;
int sblimit = fr_ps->sblimit;
static short int outsamp[1600];
static long k = 0;
if (!done)
for (i=0;i<num;i++) for (j=0;j<SBLIMIT;j++) {
(*psampFrames)++;
for (l=0;l<stereo;l++) {
if (!(k%1600) && k) {
fwrite(outsamp,2,1600,outFile);
k = 0;
}
outsamp[k++] = pcm_sample[l][i][j];
}
}
else {
fwrite(outsamp,2,(int)k,outFile);
k = 0;
}
}
void buffer_CRC(Bit_stream_struc *bs, unsigned int *old_crc)
{
*old_crc = getbits(bs, 16);
}
extern int bitrate[3][15];
extern double s_freq[4];
/* Return the number of slots for main data of current frame, */
int main_data_slots(frame_params fr_ps)
{
int nSlots;
nSlots = (144 * bitrate[2][fr_ps.header->bitrate_index])
/ s_freq[fr_ps.header->sampling_frequency];
if (fr_ps.header->padding) nSlots++;
nSlots -= 4;
if (fr_ps.header->error_protection)
nSlots -= 2;
if (fr_ps.stereo == 1)
nSlots -= 17;
else
nSlots -=32;
return(nSlots);
}
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