title: ffmpeg HE-AAC 'unsupported codec' despite being compiled with support
body: <p>Lack of default support of AAC for ffmpeg is really annoying:</p>
  
  <p>My ffmpeg version:</p>
  
  <pre><code>ffmpeg version git-2020-05-02-0d81edc Copyright (c) 2000-2020 the FFmpeg developers
    built with Apple clang version 11.0.0 (clang-1100.0.33.17)
    configuration: --prefix=/usr/local/Cellar/ffmpeg/HEAD-0d81edc_1 --enable-shared --cc=clang --host-cflags=-fno-stack-check --host-ldflags= --enable-gpl --enable-libaom --enable-libmp3lame --enable-libopus --enable-libsnappy --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --disable-libjack --disable-indev=jack --enable-opencl --enable-videotoolbox --disable-htmlpages --enable-libbluray --enable-libfdk-aac --enable-libopenh264 --enable-libopenjpeg --enable-librsvg --enable-libspeex --enable-libsrt --enable-libtwolame --enable-libwavpack --enable-libwebp --enable-libxvid --enable-nonfree --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb
  </code></pre>
  
  <p>I have several segment.ts files in <code>edit.txt</code> and I try to concatenate and convert to mpg:
  <code>ffmpeg -f concat -i edit.txt -c copy   output.mpg</code></p>
  
  <p>this does not work</p>
  
  <pre><code>Input #0, concat, from 'edit.txt':
    Duration: N/A, start: 0.000000, bitrate: 121 kb/s
      Stream #0:0: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p(progressive), 1280x720, 30 fps, 29.97 tbr, 90k tbn, 60 tbc
      Stream #0:1: Audio: aac (HE-AAC) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 121 kb/s
  File 'output.mpg' already exists. Overwrite? [y/N] y
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (copy)
    Stream #0:1 -&gt; #0:1 (aac (native) -&gt; aac (libfdk_aac))
  Press [q] to stop, [?] for help
  [mpeg @ 0x7f8e44807e00] VBV buffer size not set, using default size of 230KB
  If you want the mpeg file to be compliant to some specification
  Like DVD, VCD or others, make sure you set the correct buffer size
  [mpeg @ 0x7f8e44807e00] Unsupported audio codec. Must be one of mp1, mp2, mp3, 16-bit pcm_dvd, pcm_s16be, ac3 or dts.
  Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
  Error initializing output stream 0:1 --
  Conversion failed!
  </code></pre>
  
  <p>so I tried with <code>ffmpeg -f concat -i edit.txt -c:v copy -c:a libfdk_aac  output.mpg</code> -> same effect.</p>
  
  <p>Why fraunhoffer codec exists and is mentioned on FFMPEG site if it is not supported?
  Is it any way to do this?</p>