<p>I need an encoder that can convert mp3 files to he-aac (aka aac+).
So far the best one I have found is <a href="http://www.nero.com/eng/down-ndaudio.php" rel="nofollow noreferrer">nero aac encoder</a> . 
I have two problemes with it :
  - Only one input format : wav . It is a little bit slow to transform mp3 files to wav and then to he-aac.
  - a free license for <strong>non commercial</strong> use.</p>

<p>Too bad ffmpeg does not support he-aac ...
There is a commercial solution, <a href="https://flix.on2.com/" rel="nofollow noreferrer">on2 flix</a>, but it seems to be a golden hammer for the simple task I need to do.</p>

[{'answer_id': 81537, 'author': 'Dark Shikari', 'author_id': 11206, 'author_profile': 'https://Stackoverflow.com/users/11206', 'pm_score': 4, 'selected': True, 'text': "<p>Nero AAC is the only one as far as I know.  Even if FAAC supported HE-AAC it would be useless, since as an encoder its pretty awfully designed and its quality is not even competitive with LAME, let alone a good AAC encoder.</p>\n\n<p>Kostya on the FFMPEG team is currently working on an AAC encoder but it has a long way to go--its not ready for primetime with LC-AAC, let alone HE-AAC (its not even committed to the repository yet).  The first step before anything will be to get the ffmpeg decoder to support HE-AAC; currently it can only be decoded through FAAD.</p>\n\n<p>I don't believe there is <em>any</em> HE-AAC encoder on any platform with a more permissive license than Nero's at this point in time.</p>\n"}, {'answer_id': 436512, 'author': 'catlan', 'author_id': 23028, 'author_profile': 'https://Stackoverflow.com/users/23028', 'pm_score': 0, 'selected': False, 'text': '<p>I don\'t have an idea about the quality, but I just found\n<a href="http://dgaapenc.berlios.de/en/" rel="nofollow noreferrer">enhAacPlusEnc</a></p>\n'}, {'answer_id': 440914, 'author': 'catlan', 'author_id': 23028, 'author_profile': 'https://Stackoverflow.com/users/23028', 'pm_score': 1, 'selected': False, 'text': '<p>Another encoder: <a href="http://teknoraver.net/software/mp4tools/" rel="nofollow noreferrer">mp4tools</a></p>\n'}, {'answer_id': 4600868, 'author': 'polemon', 'author_id': 414121, 'author_profile': 'https://Stackoverflow.com/users/414121', 'pm_score': 2, 'selected': False, 'text': "<p>I've been using <code>neroAacEnc</code> for quite a while now, and I'm largely satisfied with the results. If you're on Linux, making an <code>.AAC</code> file out of an <code>.MP3</code> or whatever else, is quite easy, all you need is a small wrapper script, that takes care of decoding into <code>.WAV</code> and after encoding, removes the <code>.WAV</code> file.</p>\n\n<p>Be advised: Converting from one lossy encoding to another further reduces quality. So when you can live with <code>.MP3</code> and you don't have lossless sources, you better stick to them.</p>\n\n<p>Here's a small script, that converts from <code>.FLAC</code>to <code>.AAC</code>, it accepts only <code>.FLAC</code> files as arguments:</p>\n\n<pre><code>#!/bin/zsh\n\nfor file in ${argv[*]}; do\n    flac -d ${file}\n    neroAacEnc -q 0.6 -if ${file%%.flac}.wav -of ${file%%.flac}.aac\n    rm ${file%%.flac}.wav\ndone\n</code></pre>\n\n<p>This script is sequential, but it can be easily made into a multithreaded script.</p>\n"}, {'answer_id': 8120392, 'author': 'freechelmi', 'author_id': 1016264, 'author_profile': 'https://Stackoverflow.com/users/1016264', 'pm_score': 2, 'selected': False, 'text': '<p>There is an encoder called <code>accplus</code> which is under the GNU license <a href="http://ffmpeg.org/doxygen/trunk/libaacplus_8c-source.html" rel="nofollow">available here</a>.</p>\n'}]
['https://Stackoverflow.com/questions/81497', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/11897/']