Question

如何用MFC制作音乐波形

已经用MFC制作了一个简单的音乐播放器，现在想添加一个类似 千千静听 那个播放波形的模块 不知哪位大虾可以指导一下？小弟感激不尽。
做实时的频谱分析也可以~~~~~~急！！！

Answer 1

我做过，但播放模块使用的是Direct Sound。
频谱分析需要用FFT变换，给你提供一下我的代码（c++）
/*==============================================================
快速傅立叶变换 模块
================================================================*/
inline unsigned int NumberOfBitsNeeded( unsigned int p_nSamples )
{

int i;

if( p_nSamples < 2 )
{
return 0;
}

for ( i=0; ; i++ )
{
if( p_nSamples & (1 << i) ) return i;
}

}
inline unsigned int ReverseBits(unsigned int p_nIndex, unsigned int p_nBits)
{

unsigned int i, rev;

for(i=rev=0; i < p_nBits; i++)
{
rev = (rev << 1) | (p_nIndex & 1);
p_nIndex >>= 1;
}

return rev;

}
inline double Index_to_frequency(unsigned int p_nBaseFreq, unsigned int p_nSamples, unsigned int p_nIndex)
{

if(p_nIndex >= p_nSamples)
{
return 0.0;
}
else if(p_nIndex <= p_nSamples/2)
{
return ( (double)p_nIndex / (double)p_nSamples * p_nBaseFreq );
}
else
{
return ( -(double)(p_nSamples-p_nIndex) / (double)p_nSamples * p_nBaseFreq );
}

}
void FFT (unsigned int p_nSamples, bool p_bInverseTransform, double *p_lpRealIn, double *p_lpImagIn, double *p_lpRealOut, double *p_lpImagOut)
{

if(!p_lpRealIn || !p_lpRealOut || !p_lpImagOut) return;

unsigned int NumBits;
unsigned int i, j, k, n;
unsigned int BlockSize, BlockEnd;

double angle_numerator = 2.0 * PI;
double tr, ti;

if( p_bInverseTransform ) angle_numerator = -angle_numerator;

NumBits = NumberOfBitsNeeded ( p_nSamples );

for( i=0; i < p_nSamples; i++ )
{
j = ReverseBits ( i, NumBits );
p_lpRealOut[j] = p_lpRealIn[i];
p_lpImagOut[j] = (p_lpImagIn == NULL) ? 0.0 : p_lpImagIn[i];
}

BlockEnd = 1;
for( BlockSize = 2; BlockSize <= p_nSamples; BlockSize <<= 1 )
{
double delta_angle = angle_numerator / (double)BlockSize;
double sm2 = sin ( -2 * delta_angle );
double sm1 = sin ( -delta_angle );
double cm2 = cos ( -2 * delta_angle );
double cm1 = cos ( -delta_angle );
double w = 2 * cm1;
double ar[3], ai[3];

for( i=0; i < p_nSamples; i += BlockSize )
{

ar[2] = cm2;
ar[1] = cm1;

ai[2] = sm2;
ai[1] = sm1;

for ( j=i, n=0; n < BlockEnd; j++, n++ )
{

ar[0] = w*ar[1] - ar[2];
ar[2] = ar[1];
ar[1] = ar[0];

ai[0] = w*ai[1] - ai[2];
ai[2] = ai[1];
ai[1] = ai[0];

k = j + BlockEnd;
tr = ar[0]*p_lpRealOut[k] - ai[0]*p_lpImagOut[k];
ti = ar[0]*p_lpImagOut[k] + ai[0]*p_lpRealOut[k];

p_lpRealOut[k] = p_lpRealOut[j] - tr;
p_lpImagOut[k] = p_lpImagOut[j] - ti;

p_lpRealOut[j] += tr;
p_lpImagOut[j] += ti;

}
}

BlockEnd = BlockSize;

}

if( p_bInverseTransform )
{
double denom = (double)p_nSamples;

for ( i=0; i < p_nSamples; i++ )
{
p_lpRealOut[i] /= denom;
p_lpImagOut[i] /= denom;
}
}

}
/*===================================================================

=====================================================================*/
如果你是做软件的，这些应该看得懂，
还有个使用的实例，我做的声音变调函数：
//*************************音调变换*****************************************

void __stdcall Sd72_Pitch(char *in_fn,//输入文件名
char *in_outfn,//输出文件名
long in_s,//开始位置（单位：采样）
long in_l,//处理长度（单位：采样）
double in_v)//变调幅度（(1,1.8]升调，[0.6,1)降调）
{
jFile fp,dp;
fp=in_fn;
dp=in_outfn;
dp.toend();
unsigned long filelength=dp.len()+in_l*2;
long l,i,j=0,k,m=2;
double a=in_v,ca=(abs(a-1)>0.3)?0.85:0.75,w,winpower=(a>1)?1:2,at=(a>1)?0.5:2;
l=pow(2,13);
long cl,el,jl=1;
cl=(long)(ca*l);
el=l-cl;

short *e=(short*)malloc(sizeof(short)*l*m);
short *be=(short*)malloc(sizeof(short)*l*m);
short *f=(short*)malloc(sizeof(short)*l*m);
short *bf=(short*)malloc(sizeof(short)*l*m);
double *rin=(double*)malloc(sizeof(double)*l*m);
double *iin=(double*)malloc(sizeof(double)*l*m);
double *rout=(double*)malloc(sizeof(double)*l*m);
double *iout=(double*)malloc(sizeof(double)*l*m);

fp.pointto(in_s*2-1);

fp.in(0,e,sizeof(short)*l);
memcpy(be,e,sizeof(short)*l);
////
ZeroMemory(rin,sizeof(double)*l*m);
ZeroMemory(iin,sizeof(double)*l*m);
ZeroMemory(rout,sizeof(double)*l*m);
ZeroMemory(iout,sizeof(double)*l*m);

w=2*PI/l;
for(i=0;i<l;i++)
rin[i]=(double)e[i]*pow(0.5*(cos(w*(i-l*0.5+0.5))+1),winpower);//余弦窗

C_DoEvents();
FFT(l,false,rin,iin,rout,iout);
C_DoEvents();

ZeroMemory(&rout[(long)(l*0.5)],sizeof(double)*l*0.5);
ZeroMemory(&iout[(long)(l*0.5)],sizeof(double)*l*0.5);
ZeroMemory(rin,sizeof(double)*l*m);
ZeroMemory(iin,sizeof(double)*l*m);

if(a>1 && a<=1.8)
{
FcZero(rout,l*0.5,rin,(l*0.5)*a);
FcZero(iout,l*0.5,iin,(l*0.5)*a);
}

if(a>=0.6 && a<1)
{
FcTo(rout,l*0.5,rin,(l*0.5)*a);
FcTo(iout,l*0.5,iin,(l*0.5)*a);
}

ZeroMemory(rout,sizeof(double)*l*m);
ZeroMemory(iout,sizeof(double)*l*m);

C_DoEvents();
FFT(l*m,true,rin,iin,rout,iout);
C_DoEvents();

FcTo(rout,l*m,iout,l);//iout出

for(i=0;i<l;i++)
f[i]=(short)(iout[i]*at);
////
memcpy(bf,f,sizeof(short)*l);

while(jl==1)
{
fp.in(0,&e[cl],sizeof(short)*el);
memcpy(e,&be[el],sizeof(short)*cl);
memcpy(be,e,sizeof(short)*l);
////
ZeroMemory(rin,sizeof(double)*l*m);
ZeroMemory(iin,sizeof(double)*l*m);
ZeroMemory(rout,sizeof(double)*l*m);
ZeroMemory(iout,sizeof(double)*l*m);

w=2*PI/l;
for(i=0;i<l;i++)
rin[i]=(double)e[i]*pow(0.5*(cos(w*(i-l*0.5+0.5))+1),winpower);//余弦窗

C_DoEvents();
FFT(l,false,rin,iin,rout,iout);
C_DoEvents();

ZeroMemory(&rout[(long)(l*0.5)],sizeof(double)*l*0.5);
ZeroMemory(&iout[(long)(l*0.5)],sizeof(double)*l*0.5);
ZeroMemory(rin,sizeof(double)*l*m);
ZeroMemory(iin,sizeof(double)*l*m);

if(a>1 && a<=1.8)
{
FcZero(rout,l*0.5,rin,(l*0.5)*a);
FcZero(iout,l*0.5,iin,(l*0.5)*a);
}

if(a>=0.6 && a<1)
{
FcTo(rout,l*0.5,rin,(l*0.5)*a);
FcTo(iout,l*0.5,iin,(l*0.5)*a);
}

ZeroMemory(rout,sizeof(double)*l*m);
ZeroMemory(iout,sizeof(double)*l*m);

C_DoEvents();
FFT(l,true,rin,iin,rout,iout);
C_DoEvents();

for(i=0;i<l;i++)
f[i]=(short)(rout[i]*at);
////
for(k=0;k<cl;k++)
{
f[k]=f[k]+bf[k+el];// ^_^ 重叠叠加，使声音变平滑
}
dp.out(0,bf,sizeof(short)*el);
in_l-=el;
if(in_l<=0)
jl=0;
memcpy(bf,f,sizeof(short)*l);
}
fp.leave(NULL,JFILE_NORMAL);
dp.leave(NULL,filelength);
}
//*********************************************************************************

如果不懂，等我高考完了可以和我探讨探讨，QQ：994373259

Answer 2

听说是要进行FFT变换~~~不过这变换有点复杂，之前我也想过做类似这种效果……