title: How to transcode video stream by changing only the resolution?
body: <p>I would like to transcode video stream using ffmpeg tool and change only the video stream resolution, i.e. the video and audio parameters should remain the same.</p>
  
  <p>According to the man page of the ffmpeg the following command line should provide the desired result:</p>
  
  <pre><code>ffmpeg -i input.mp4 -vcodec copy -acodec copy -s WxH output.avi
  </code></pre>
  
  <p>The Video codec of the input stream is compatible with avi container.</p>
  
  <p>The actual result is that the resolution remains unchanged and it seems that the stream is just repacked in avi container.</p>
  
  <p>The resolution of the output stream is changed successfully without <code>-vcodec copy</code> option, but the video codec is changed:  h264 (Constrained Baseline) - > mpeg4 (Simple Profile).</p>