title: Using ffmpeg to merge two audio file and one video file with control volume?
body: <p>I want to use ffmpeg to merge 2 audio files with one video file to create one video file, but in audio file I want to control the volume level of each file. </p>
  
  <p>What should I do ?</p>
  
  <pre><code>ffmpeg -i video.mp4 -i input1.mp3 -i input2.mp3
  -filter_complex "[1]volume=0.5,pan=2c[a];[2]volume=0.7,pan=2c[b];[a][b]amix=duration=shortest"
  -ac 2 -c:a libmp3lame -q:v 0 output.mp4
  </code></pre>