diff --git a/moviepy/audio/io/ffmpeg_audiowriter.py b/moviepy/audio/io/ffmpeg_audiowriter.py
index 952179e65..2de9f107e 100644
--- a/moviepy/audio/io/ffmpeg_audiowriter.py
+++ b/moviepy/audio/io/ffmpeg_audiowriter.py
@@ -52,6 +52,7 @@ def __init__(self, filename, fps_input, nbytes=2, nchannels = 2,
                  [ "-i", input_video, '-vcodec', 'copy'])
             + ['-acodec', codec]
             + ['-ar', "%d"%fps_input]
+            + ['-strict', '-2']  # needed to support codec 'aac'
             + (['-ab',bitrate] if (bitrate!=None) else [])
             + [ filename ])
         
diff --git a/moviepy/video/VideoClip.py b/moviepy/video/VideoClip.py
index 3e830bc98..477721d12 100644
--- a/moviepy/video/VideoClip.py
+++ b/moviepy/video/VideoClip.py
@@ -192,6 +192,7 @@ def verbose_print(s):
                 D_ext = {'libmp3lame': 'mp3',
                        'libvorbis':'ogg',
                        'libfdk_aac':'m4a',
+                       'aac':'m4a',
                        'pcm_s16le':'wav',
                        'pcm_s32le': 'wav'}