我正在尝试对样本进行音高转换。我正在使用线性插值方法。
如果音高的数量是一个整数值，则音高被干净地移动。如果音高偏移量是合理的，则声音会严重失真。该实施似乎有效。
这是我的代码，我试图很好地评论。
public void generateOutTrack()
{
Note currNote;
float[] output=new float[pattern.getPlayTimeInSmps()];//returns total play time of pattern in #samples.
float[] currSample=sample.getData();//the pcm data of the sample to be used
int currPeriod=0;//length of next note in number of samples
int outputPtr=0;//points to next sample in output buffer array
float pitch;//amount to pitch sample by
float linInt=0;//linear interpolater
float phasePtr=0;//floating point index in sample
int ptr=0;//integer index into sample
JavAud.checkRange(currSample);
while((currNote=pattern.nextNote())!=null)//each iteration plays one note
{
currPeriod=currNote.getPeriodInSmps();//length of current note in samples
pitch=currNote.getPitch();//pitch of current note
for(int i=0;i<currPeriod;i++)//run for length of note
{
ptr=(int)phasePtr;//floor of floating point index
linInt=phasePtr-ptr;
//if we are not at end of sample copy data to output
if(ptr<currSample.length*(1/pitch)-1)
{
//linear interpolation pitch shifting
output[outputPtr]=(currSample[ptr+1]*linInt)+(currSample[ptr]*(1-linInt));
//alternate pitch shifting by simple sample dropping(has less distortion)
//output[outputPtr]=currSample[ptr];
}
else//else silent
{
output[outputPtr]=0;
}
outputPtr++;
phasePtr=phasePtr+pitch;
}
phasePtr=0;
}
JavAud.checkRange(output);
WavFileWriter writer = new WavFileWriter();
writer.writeWave(new WavFile(1, JavAud.GLB_SMP_RATE, output), "outputTone.wav");
}