title: ffmpeg generate overlay complex filter for audio with background image
body: <p>I am experimenting with ffmpeg and would like to generate overlay complex filter for audio with background image. The code normally works, except for when adding <code>-filter_complex "[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a</code> 
  it crashes. I found the example code at <a href="https://trac.ffmpeg.org/wiki/Waveform" rel="nofollow">https://trac.ffmpeg.org/wiki/Waveform</a> Any help is appreciated.</p>
  
  <pre><code>Command '['c:/ffmpeg/bin\\ffmpeg.exe', '-y', '-loop', '1', '-r', '1', '-i', 'temp\\bg.png', '-i', 'test.mp3', '-filter_complex', '[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]', '-map', '[v]', '-map', '0:a', '-c:v', 'libx264', '-preset', 'ultrafast', '-tune', 'stillimage', '-crf', '15', '-pix_fmt', 'yuv420p', '-strict', 'experimental', '-c:a', 'aac', '-b:a', '256k', '-shortest', '-threads', '0', 'done/test.mp4']'
  </code></pre>
  
  <p>EDIT 1:</p>
  
  <p>I tested this with the new verson: <code>ffmpeg -y -i input.mp3 -i background.png -filter_complex "[0:a]showwaves=s=1280x720:mode=line,format=yuv420p[v]" -map "[v]" -map 0:a -c:v libx264 -c:a copy output.mp4</code></p>
  
  <p>It generates an output file, but only the waveform, no background included. My end goal is to generate the waveform over the background.</p>