title: DirectShow Capture Source and FFMPEG
body: <p>I have an AJA Capture card. The drivers installed with the card include some DirectShow filter. If I pop the filter into GraphEdit I see this:</p>
  
  <p><img src="https://i.stack.imgur.com/x75UI.png" alt="AJA Capture Filter in GraphEdit"></p>
  
  <p>and if I run the ffmpeg command</p>
  
  <pre><code>ffmpeg -f dshow -list_options true -i video="AJA Capture Source"
  </code></pre>
  
  <p>I see</p>
  
  <pre><code>[dshow @ 0034eec0] DirectShow video device options
  [dshow @ 0034eec0]  Pin "Video"
  [dshow @ 0034eec0]   pixel_format=yuyv422  min s=720x486 fps=27.2604 max s=1024x
  486 fps=29.985
  ...
  [dshow @ 0034eec0]  Pin "Audio 1-2"
  [dshow @ 0034eec0]  Pin "Line21"
  video=AJA Capture Source: Immediate exit requested
  </code></pre>
  
  <p>So I see the Video and Audio pins I need. But when I try to run an ffmpeg command to capture both, I can only figure out how to do the video part. How do I hook in to that audio pin? It seems all the examples and documentation point to using a separate audio device, and nothing about hooking into the pins. I'm running it out of a batch file for now like this and I use the ^ to break the line</p>
  
  <pre><code>ffmpeg.exe ^
  -y ^
  -rtbufsize 100M ^
  -f dshow ^
  -i video="AJA Capture Source" ^
  -t 00:00:10 ^
  -aspect 16:9 ^
  -c:v libx264 ^
  "C:\VCS_AUD_SAMPLE.mp4"
  </code></pre>
  
  <p>Again, the command above will get me some beautiful video, but I can't figure out the audio part. Is this even supported in ffmpeg or am I going to have to modify the ffmpeg dshow code?</p>