Question

I have to convert a matlab code into Android. This matlab code contains energy calculation as shown below:

first I read the audio file into matrix x, and the sample frequency into fs, and then calculate the energy for each window:

[x, fs] = wavread('C:\1359873105438.wav')
energy=energy+sum(x(1:fs).^2)*Tss;

I am not sure how to convert this into Android/Java.

Have you been through this before? please help me to get over this problem.

thanks in advance for your help

Answer 1

Essentially, you have to do something like this:

double x;//Read Wave in here
for (i=0;i<x.length;i++)
{
    energy+=Tss*(x[i]^2);
}

How to read the wave files borrowed from this article.

public class ReadExample
{
   public static void main(String[] args)
   {
      try
      {
         // Open the wav file specified as the first argument
         WavFile wavFile = WavFile.openWavFile(new File(args[0]));

         // Get the number of audio channels in the wav file
         int numChannels = wavFile.getNumChannels();

         // Create a buffer of 100 frames
         double[] buffer = new double[100 * numChannels];

         int framesRead;

         do
         {
            // Read frames into buffer
            framesRead = wavFile.readFrames(buffer, 100);

            // Loop through frames and look for minimum and maximum value
            for (int s=0 ; s<framesRead * numChannels ; s++)
            {
               //This is where you put the your code in
            }
         }
         while (framesRead != 0);

         // Close the wavFile
         wavFile.close();
      }
      catch (Exception e)
      {
         System.err.println(e);
      }
   }
}

Bottom line is, there isn’t a nice clean way to do it like there is in matlab. There isn’t even a function to directly read in a wave file. Still, it’s relatively straight forward, using the WavFile class the website provides.