title: FFMPEG picture in picture
body: <p>I try to put a portion of video in a video at a certain time. </p>
  
  <p>Se here's my command:</p>
  
  <pre><code>./ffmpeg-3.0-32bit-static/ffmpeg \
  -y \
  -i main.mp4 \
  -itsoffset -10 \
  -i overlay.mp4 \
  -filter_complex \
  "[1:a] atrim=5:20 [1:a1]; \
  [1:a1] adelay=5000|5000 [1:a2]; \
  [0:a][1:a2] amix [outa]; \
  [1:v] scale=120:-1 [1:v1]; \
  [0:v][1:v1] overlay=x=25:y=25:enable='between(t,5,20)'[outv]" \
  -map "[outv]" \
  -map "[outa]" \
  -c:a aac \
  -c:v libx264 \
  -vb 1000k \
  -r 24 \
  -strict -2 \
  output.mp4
  </code></pre>
  
  <p>But I've got "Buffer queue overflow, dropping" messages which, I think, makes my overlay.mp4 a little jerky on the output.mp4 :</p>
  
  <pre><code>[Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.
      Last message repeated 50 times
  [Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.0.927x
  [Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.=2.72x
      Last message repeated 33 times
  [Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.=2.72x
      Last message repeated 14 times
  [Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.=2.97x
      Last message repeated 13 times
  [Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.=3.16x
      Last message repeated 35 times
  [Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.=3.35x
      Last message repeated 45 times
  [Parsed_overlay_4 @ 0xc29d9c0] [framesync @ 0xc29da84] Buffer queue overflow, dropping.=3.46x
      Last message repeated 5 times
  </code></pre>
  
  <p>Any idea why?</p>
  
  <p>EDIT: Forgot to say I've got the last version of ffmpeg => 3.0.</p>