音频去噪C++代码，注释清晰可用

#include "Platform.h" #include "avsmallft.h" static void drfti1(int n,float *wa,int *ifac) { static int ntryh[4] = { 4,2,3,5 }; static float tpi = 6.28318530717958648f; float arg,argh,argld,fi; int ntry=0,i,j=-1; int k1, l1, l2, ib; int ld, ii, ip, is, nq, nr; int ido, ipm, nfm1; int nl=n; int nf=0; L101: j++; if (j < 4) ntry=ntryh[j]; else ntry+=2; L104: nq=nl/ntry; nr=nl-ntry*nq; if (nr!=0) goto L101; nf++; ifac[nf+1]=ntry; nl=nq; if(ntry!=2)goto L107; if(nf==1)goto L107; for (i=1;i<nf;i++) { ib=nf-i+1; ifac[ib+1]=ifac[ib]; } ifac[2] = 2; L107: if(nl!=1)goto L104; ifac[0]=n; ifac[1]=nf; argh=tpi/n; is=0; nfm1=nf-1; l1=1; if(nfm1==0)return; for (k1=0;k1<nfm1;k1++) { ip=ifac[k1+2]; ld=0; l2=l1*ip; ido=n/l2; ipm=ip-1; for (j=0;j<ipm;j++) { ld += l1; i = is; argld = (float)ld*argh; fi = 0.f; for (ii=2;ii<ido;ii+=2) { fi += 1.f; arg = fi*argld; wa[i++] = cosf(arg); wa[i++] = sinf(arg); } is+=ido; } l1=l2; } } static void fdrffti(int n,float *wsave,int *ifac) { if (n == 1) return; drfti1(n, wsave+n, ifac); } static void dradf2(int ido,int l1,float *cc,float *ch,float *wa1) { int i,k; float ti2,tr2; int t0,t1,t2,t3,t4,t5,t6; t1=0; t0=(t2=l1*ido); t3=ido<<1; for(k=0;k<l1;k++) { ch[t1<<1]=cc[t1]+cc[t2]; ch[(t1<<1)+t3-1]=cc[t1]-cc[t2]; t1+=ido; t2+=ido; } if(ido<2)return; if(ido==2)goto L105; t1=0; t2=t0; for(k=0;k<l1;k++) { t3=t2; t4=(t1<<1)+(ido<<1); t5=t1; t6=t1+t1; for(i=2;i<ido;i+=2) { t3+=2; t4-=2; t5+=2; t6+=2; tr2=wa1[i-2]*cc[t3-1]+wa1[i-1]*cc[t3]; ti2=wa1[i-2]*cc[t3]-wa1[i-1]*cc[t3-1]; ch[t6]=cc[t5]+ti2; ch[t4]=ti2-cc[t5]; ch[t6-1]=cc[t5-1]+tr2; ch[t4-1]=cc[t5-1]-tr2; } t1+=ido; t2+=ido; } if(ido%2==1)return; L105: t3=(t2=(t1=ido)-1); t2+=t0; for(k=0;k<l1;k++) { ch[t1]=-cc[t2]; ch[t1-1]=cc[t3]; t1+=ido<<1; t2+=ido; t3+=ido; } } static void dradf4(int ido,int l1,float *cc,float *ch,float *wa1,float *wa2,float *wa3) { static float hsqt2 = .70710678118654752f; int i,k,t0,t1,t2,t3,t4,t5,t6; float ci2,ci3,ci4,cr2,cr3,cr4,ti1,ti2,ti3,ti4,tr1,tr2,tr3,tr4; t0=l1*ido; t1=t0; t4=t1<<1; t2=t1+(t1<<1); t3=0; for(k=0;k<l1;k++) { tr1=cc[t1]+cc[t2]; tr2=cc[t3]+cc[t4]; ch[t5=t3<<2]=tr1+tr2; ch[(ido<<2)+t5-1]=tr2-tr1; ch[(t5+=(ido<<1))-1]=cc[t3]-cc[t4]; ch[t5]=cc[t2]-cc[t1]; t1+=ido; t2+=ido; t3+=ido; t4+=ido; } if(ido<2)return; if(ido==2)goto L105; t1=0; for(k=0;k<l1;k++) { t2=t1; t4=t1<<2; t5=(t6=ido<<1)+t4; for(i=2;i<ido;i+=2) { t3=(t2+=2); t4+=2; t5-=2; t3+=t0; cr2=wa1[i-2]*cc[t3-1]+wa1[i-1]*cc[t3]; ci2=wa1[i-2]*cc[t3]-wa1[i-1]*cc[t3-1]; t3+=t0; cr3=wa2[i-2]*cc[t3-1]+wa2[i-1]*cc[t3]; ci3=wa2[i-2]*cc[t3]-wa2[i-1]*cc[t3-1]; t3+=t0; cr4=wa3[i-2]*cc[t3-1]+wa3[i-1]*cc[t3]; ci4=wa3[i-2]*cc[t3]-wa3[i-1]*cc[t3-1]; tr1=cr2+cr4; tr4=cr4-cr2; ti1=ci2+ci4; ti4=ci2-ci4; ti2=cc[t2]+ci3; ti3=cc[t2]-ci3; tr2=cc[t2-1]+cr3; tr3=cc[t2-1]-cr3; ch[t4-1]=tr1+tr2; ch[t4]=ti1+ti2; ch[t5-1]=tr3-ti4; ch[t5]=tr4-ti3; ch[t4+t6-1]=ti4+tr3; ch[t4+t6]=tr4+ti3; ch[t5+t6-1]=tr2-tr1; ch[t5+t6]=ti1-ti2; } t1+=ido; } if(ido&1)return; L105: t2=(t1=t0+ido-1)+(t0<<1); t3=ido<<2; t4=ido; t5=ido<<1; t6=ido; for(k=0;k<l1;k++) { ti1=-hsqt2*(cc[t1]+cc[t2]); tr1=hsqt2*(cc[t1]-cc[t2]); ch[t4-1]=tr1+cc[t6-1]; ch[t4+t5-1]=cc[t6-1]-tr1; ch[t4]=ti1-cc[t1+t0]; ch[t4+t5]=ti1+cc[t1+t0]; t1+=ido; t2+=ido; t4+=t3; t6+=ido; } } static void dradfg(int ido,int ip,int l1,int idl1,float *cc,float *c1,float *c2,float *ch,float *ch2,float *wa) { static float tpi=6.283185307179586f; int idij,ipph,i,j,k,l,ic,ik,is; int t0,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10; float dc2,ai1,ai2,ar1,ar2,ds2; int nbd; float dcp,arg,dsp,ar1h,ar2h; int idp2,ipp2; arg =tpi/(float)ip; dcp = cosf(arg); dsp = sinf(arg); ipph = (ip+1)>>1; ipp2 = ip; idp2 = ido; nbd = (ido-1)>>1; t0 = l1*ido; t10 = ip*ido; if(ido == 1) goto L119; for(ik = 0; ik < idl1; ik++) ch2[ik]=c2[ik]; t1=0; for(j=1;j<ip;j++) { t1+=t0; t2=t1; for(k=0;k<l1;k++) { ch[t2]=c1[t2]; t2+=ido; } } is=-ido; t1=0; if(nbd>l1) { for(j=1;j<ip;j++) { t1+=t0; is+=ido; t2= -ido+t1; for(k=0;k<l1;k++) { idij=is-1; t2+=ido; t3=t2; for(i=2;i<ido;i+=2) { idij+=2; t3+=2; ch[t3-1]=wa[idij-1]*c1[t3-1]+wa[idij]*c1[t3]; ch[t3]=wa[idij-1]*c1[t3]-wa[idij]*c1[t3-1]; } } } } else { for(j=1;j<ip;j++) { is+=ido; idij=is-1; t1+=t0; t2=t1; for(i=2;i<ido;i+=2) { idij+=2; t2+=2; t3=t2; for(k=0;k<l1;k++) { ch[t3-1]=wa[idij-1]*c1[t3-1]+wa[idij]*c1[t3]; ch[t3]=wa[idij-1]*c1[t3]-wa[idij]*c1[t3-1]; t3+=ido; } } } } t1=0; t2=ipp2*t0; if(nbd<l1) { for(j=1;j<ipph;j++) { t1+=t0; t2-=t0; t3=t1; t4=t2; for(i=2;i<ido;i+=2) { t3+=2; t4+=2; t5=t3-ido; t6=t4-ido; for(k=0;k<l1;k++) { t5+=ido; t6+=ido; c1[t5-1]=ch[t5-1]+ch[t6-1]; c1[t6-1]=ch[t5]-ch[t6]; c1[t5]=ch[t5]+ch[t6]; c1[t6]=ch[t6-1]-ch[t5-1]; } } } } else { for(j=1;j<ipph;j++) { t1+=t0; t2-=t0; t3=t1; t4=t2; for(k=0;k<l1;k++) { t5=t3; t6=t4; for(i=2;i<ido;i+=2) { t5+=2; t6+=2; c1[t5-1]=ch[t5-1]+ch[t6-1]; c1[t6-1]=ch[t5]-ch[t6]; c1[t5]=ch[t5]+ch[t6]; c1[t6]=ch[t6-1]-ch[t5-1]