title: Why does mp3lame conversion from mp3float not work for rtmp?
body: <p>I am creating a rtmp stream using FFMPEG and sending the data to local NGINX server with the RTMP module.  </p>
  
  <p>The originally stream is mp3float, however the conversion to Mp3lame did not work while flv did , how comes?</p>
  
  <p>Doesn't work but no errors   </p>
  
  <pre><code>fmpeg -hide_banner -loglevel warning -i http://x.x.x.x:8138 -f mp3 rtmp://localhost/live
  </code></pre>
  
  <p>Works with no errors   </p>
  
  <pre><code>fmpeg -hide_banner -loglevel warning -i http://x.x.x.x:8138 -f flv rtmp://localhost/live
  </code></pre>