void ampegdecoder::seekinit3(int discard)
{
int i,j,k;
int extra=(seekmode==seekmodeexact)?1:0;
if ((discard>=seekinitframes)&&extra)
for (i=0; i<2; i++)
for (j=0; j<32; j++)
for (k=0; k<18; k++)
prevblck[i][j][k]=0;
huffoffset=0;
for (i=discard; i<seekinitframes; i++)
if (i<(seekinitframes-extra))
for (j=0; j<(hdrlsf?2:1); j++)
{
if (!decodehdr(0))
return;
readmain(0);
}
else
{
if (!decodehdr(0))
return;
decode3();
}
}
void ampegdecoder::decode1()
{
int i,j,q,fr;
for (fr=0; fr<3; fr++)
{
if (fr)
decodehdr(0);
if (!hdrbitrate)
{
for (q=0; q<12; q++)
for (j=0; j<2; j++)
for (i=0; i<32; i++)
fraction[j][12*fr+q][i]=0;
continue;
}
int bitend=mainbufpos-32-(hdrcrc?16:0)+(hdrpadding?32:0)+12*1000*ratetab[hdrlsf?1:0][0][hdrbitrate]/(freqtab[hdrfreq]>>hdrlsf)*32;
int jsbound=(hdrmode==1)?(hdrmodeext+1)*4:(hdrmode==3)?0:32;
int stereo=(hdrmode==3)?1:2;
for (i=0;i<32;i++)
for (j=0;j<((i<jsbound)?2:1);j++)
{
bitalloc1[j][i] = mpgetbits(4);
if (i>=jsbound)
bitalloc1[1][i] = bitalloc1[0][i];
}
for (i=0;i<32;i++)
for (j=0;j<stereo;j++)
if (bitalloc1[j][i])
scale1[j][i]=multiple[mpgetbits(6)]*rangefac[bitalloc1[j][i]];
for (q=0;q<12;q++)
for (i=0;i<32;i++)
for (j=0;j<((i<jsbound)?2:1);j++)
if (bitalloc1[j][i])
{
int s=mpgetbits(bitalloc1[j][i]+1)-(1<<bitalloc1[j][i])+1;
fraction[j][12*fr+q][i]=scale1[j][i]*s;
if (i>=jsbound)
fraction[1][12*fr+q][i]=scale1[1][i]*s;
}
else
{
fraction[j][12*fr+q][i]=0;
if (i>=jsbound)
fraction[1][12*fr+q][i]=0;
}
mpgetbits(bitend-mainbufpos);
}
}
void ampegdecoder::decode3()
{
int fr,gr,ch,sb,ss;
for (fr=0; fr<(hdrlsf?2:1); fr++)
{
grsistruct si0[2][2];
if (fr)
decodehdr(0);
if (!hdrbitrate)
{
for (gr=fr; gr<2; gr++)
for (ch=0; ch<2; ch++)
for (sb=0; sb<32; sb++)
for (ss=0; ss<18; ss++)
{
fraction[ch][gr*18+ss][sb]=((sb&ss&1)?-1:1)*prevblck[ch][sb][ss];
prevblck[ch][sb][ss]=0;
}
return;
}
readmain(si0);
int stereo=(hdrmode==3)?1:2;
int ngr=hdrlsf?1:2;
for (gr=0;gr<ngr;gr++)
{
for (ch=0; ch<stereo; ch++)
{
readscalefac(si0[ch][gr], scalefac0[ch]);
readhuffman(si0[ch][gr], xr0[ch]);
doscale(si0[ch][gr], xr0[ch], scalefac0[ch]);
}
if (hdrmode==1)
jointstereo(si0[1][gr], xr0, scalefac0[1]);
for (ch=0; ch<stereo; ch++)
hybrid(si0[ch][gr], fraction[ch]+(fr+gr)*18, prevblck[ch], xr0[ch]);
}
}
}
