15.1.11  Reading a wav file: readwav

The readwav command retrieves information about a wav file.

• readwav takes one argument:
  filename, a sound file (with extension .wav) stored in wav format given as a string.
• readwav(filename) returns a vector consisting of:
  • A list consisting of:
    • The number of channels (generally 1 for mono and 2 for stereo).
    • The number of bits (generally 16).
    • The sampling frequency (44100 for a CD quality sound).
    • The number of bytes (excluding the header); i.e., the number of seconds times the sampling frequency times the number of bits/8 times the number of channels.
  • A list of digital sound data for each channel.
  The result of readwav is typically stored in a variable.

  
  

  Example.
  Assuming that sound.wav is a sound file for a one-second sound in CD quality on a 16-bit channel:
  Input:

  s:= readwav("sound.wav"):;

  s[0]

  Output:

  [1,16,44100,88200]

  Input:

  size(s)

  Output:

  2

  which is the number of channels plus 1.
  Input:

  size(s[1])

  Output:

  44100