title: FFmepg Encode Video and Add Subtitles Not Working with Maps
body: <p>I'm trying to convert a video and add subtitles, but the subtitles are never added.</p>
  
  <p>It only works if I remove <code>-map 0:v?</code> and <code>-map 0:a?</code>.</p>
  
  <p>However I need maps so I can select the streams, such as <code>-map 0:a:1</code>.</p>
  
  <pre><code>ffmpeg -y 
  
  -i "C:\Users\Matt\video.mp4" 
  -i "C:\Users\Matt\subtitle.ass" 
  
  -c:v libx264 
  -preset medium -crf 37 -pix_fmt yuv420p 
  -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" 
  -map 0:v? 
  -map_chapters 0 
  
  -c:s ass 
  -map 0:s? 
  
  -c:a ac3 
  -b:a 320k 
  -map 0:a? 
  
  -map_metadata 0 
  
  "C:\Users\Matt\video.mkv"
  </code></pre>