Playing a waveform (float array) as sound

Question

I have a waveform that is represented as an array of floats from -1 to 1. Would it be possible to play this waveform as a repeated sound?

I've found numerous examples of playing audio from an array, but all relate to byte arrays, and require some very convoluted code.

Answer 1

Without knowing much about it, why don't you just assign a range to the values, and play this range tone by tone.

-1   ...      1
50Hz ... 20,000Hz

You could easily calculate it like this:

//input is the float array
int minPitch = 50;
int maxPitch = 20000;

int pitch = (int)((input[idx] + 1) * ((maxPitch - minPitch) / 2) + minPitch);

This would give you the pitch of the value in the array.

Answer 2

Assuming that your float array holds PCM data, and you want to play it in 8-bit, converting it to a byte array is easy:

              int off=(signed!=0 ? 0 : 128);
              for(int i=0; i<samples; i++){
                  val=(int)(pcm[i]*128. + 0.5);
                  if(val>127)
                    val=127;
                  else if(val<-128)
                    val=-128;
                  buffer[index++]=(byte)(val+off);
                }
              }

This code is slightly modifed code from JOrbis, here pcm is your array of floats, and buffer is the byte array.