docs: def waveform_image(mediafile, xy_size, outdir=None, center_color=None, outer_color=None, bg_color=None):
      """ Create waveform image from audio data.
          Return path to created image file.
      """
      try:
          import waveform
      except ImportError, exc:
          raise ImportError("%s [get it at https://github.com/superjoe30/PyWaveform]" % exc)
  
      outdir = outdir or os.path.dirname(mediafile)
      outfile = os.path.join(outdir, os.path.splitext(os.path.basename(mediafile))[0] + ".png")
  
      with transcode.to_wav(mediafile) as wavfile:
          # Draw using a gradient
          waveform.draw(wavfile, outfile, xy_size, 
              bgColor=bg_color or WAVE_BG_COLOR,
              fgGradientCenter=center_color or WAVE_CENTER_COLOR, 
              fgGradientOuter=outer_color or WAVE_OUTER_COLOR)
  
      return outfile