title: How to encode audio to AAC with profile FF_PROFILE_AAC_LOW
body: <p>I try to encode audio to AAC with profile <code>FF_PROFILE_AAC_LOW</code> by the following settings.</p>
  
  <pre><code>oc_cxt-&gt;profile = FF_PROFILE_AAC_LOW;
  </code></pre>
  
  <p>Also from the output of <code>av_dump_format</code>, I got this</p>
  
  <pre><code>Metadata:
  encoder         : Lavf57.36.100
  Stream #0:0: Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 192 kb/s
  </code></pre>
  
  <p>But the output is different. Everything is ok, except the output is <code>AAC</code>, not <code>AAC (LC)</code>. By using <code>ffprobe</code> to detect, the output information is</p>
  
  <pre><code>$ ffprobe o.m4a
  ...
  Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 195 kb/s (default)
  ...
  </code></pre>
  
  <p><code>AAC (LC)</code> is the desired result I need.</p>
  
  <p>But from the command line, <code>ffmpeg</code> can generate <code>AAC (LC)</code> output. Below is a small test.</p>
  
  <pre><code>$ ffmpeg -f lavfi -i aevalsrc="sin(440*2*PI*t):d=5" aevalsrc.m4a
  $ ffprobe aevalsrc.m4a
  ...
  Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 69 kb/s (default)
  ...
  </code></pre>
  
  <p>How can I select <code>FF_PROFILE_LOW</code> to get <code>AAC (LC)</code> output?</p>