title: ffserver "dimensions not set" when loading stream
body: <p>I am live streaming a webcam from my raspberry pi using avconv (ffmpeg "replacement")</p>
  
  <pre><code>avconv -f video4linux2 -v debug -r 5 -s 176x144 -i /dev/video0 -vcodec mjpeg http://192.168.0.3:8090/feed1.ffm
  </code></pre>
  
  <p>to my local network OSX machine (for testing) running ffserver</p>
  
  <pre><code>Port 8090
  BindAddress 0.0.0.0
  MaxHTTPConnections 2000
  MaxClients 1000
  MaxBandwidth 10000
  CustomLog -
  NoDaemon
  
  &lt;Feed feed1.ffm&gt;
     File feed1.ffm
     FileMaxSize 20M
     ACL allow 192.168.0.10
  &lt;/Feed&gt;
  
  &lt;Stream test.mjpeg&gt;
     Feed feed1.ffm
     Format mjpeg
     NoAudio
     VideoQMin 1
     VideoQMax 10
     VideoSize 176x144
     VideoFrameRate 5
  &lt;/Stream&gt;
  </code></pre>
  
  <p>When I start avconv it appears to be streaming to ffserver fine:</p>
  
  <pre><code>Output #0, ffm, to 'http://192.168.0.3:8090/feed1.ffm':
    Metadata:
      encoder         : Lavf55.0.1
      Stream #0.0, 0, 1/1000000: Video: mjpeg, yuvj420p, 320x240, 1/5, q=2-31, 200 kb/s, 1000k tbn, 5 tbc
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (rawvideo -&gt; mjpeg)
  Press ctrl-c to stop encoding
  frame=  108 fps= 18 q=21.7 size=     688kB time=21.60 bitrate= 260.9kbits/s 
  </code></pre>
  
  <p>And the ffserver status page shows the stream</p>
  
  <p><img src="https://i.stack.imgur.com/Y5UQd.png" alt="ffserver status"></p>
  
  <p>However when I load <code>http://localhost:8090/test.mjpeg</code> in VLC it doesn't play and ffserver spits out:</p>
  
  <pre><code>Sat May 25 17:25:34 2013 dimensions not set
  Sat May 25 17:25:34 2013 Error writing output header
  Sat May 25 17:25:34 2013 127.0.0.1 - - [GET] "/test.mjpeg HTTP/1.1" 200 66
  </code></pre>
  
  <p>I've tried so many different configurations and settings, I'm at a loss to what is causing that error! </p>
  
  <p>Thank you</p>