title: FFMPEG (Input 8K AAC -> (AAC FLV) youtube streaming noise
body: <p>Hello I run a streaming encoder for a non profit cause. Chosen FFMPEG as it's very simple and doing the job near perfectly however the audio is noisy popping and cracking. Video is crystal clear.</p>
  
  <p>ffmpeg version N-86950-g1bef008 Copyright (c) 2000-2017 the FFmpeg developers
    built with gcc 7.1.0 (GCC)</p>
  
  <p>Here is my command.</p>
  
  <pre><code>ffmpeg -rtsp_transport tcp -i $RTSP_SRC -vcodec copy -af "volume=12dB" -ar 8000 -acodec aac -f flv rtmp://a.rtmp.youtube.com/live2/$DEST_KEY
  </code></pre>
  
  <p>However when I just play the stream the noise levels are quite acceptable.</p>
  
  <pre><code>ffplay -rtsp_transport tcp -i $RTSP_SRC
  </code></pre>
  
  <p>What I have tried so far.</p>
  
  <ul>
  <li>Change input audio sampling from 8K to 16K (that's all is supported currently). It made the noise problem much worse. I can't change it to a native FLV sampling(44100 or 22050 or 11025) at least not yet, the integrated rtsp stream does not support it.)</li>
  <li>My working theory is during resampling stream noise is getting boosted. So to eliminate that I tried audio copy codec even then there is no significant improvement. </li>
  </ul>