m4a: aac in mp4 container (Closes #240)

diff --git a/youtube_dl/__init__.py b/youtube_dl/__init__.py
index ecc000f..3fed554 100755 (executable)
--- a/youtube_dl/__init__.py
+++ b/youtube_dl/__init__.py
@@ -3968,8 +3968,13 @@ class FFmpegExtractAudioPP(PostProcessor):
                        return None
 
                more_opts = []
-               if self._preferredcodec == 'best' or self._preferredcodec == filecodec:
-                       if filecodec in ['aac', 'mp3', 'vorbis']:
+               if self._preferredcodec == 'best' or self._preferredcodec == filecodec or (self._preferredcodec == 'm4a' and filecodec == 'aac'):
+                       if self._preferredcodec == 'm4a' and filecodec == 'aac':
+                               # Lossless, but in another container
+                               acodec = 'copy'
+                               extension = self._preferredcodec
+                               more_opts = ['-absf', 'aac_adtstoasc']
+                       elif filecodec in ['aac', 'mp3', 'vorbis']:
                                # Lossless if possible
                                acodec = 'copy'
                                extension = filecodec
@@ -3986,13 +3991,15 @@ class FFmpegExtractAudioPP(PostProcessor):
                                        more_opts += ['-ab', self._preferredquality]
                else:
                        # We convert the audio (lossy)
-                       acodec = {'mp3': 'libmp3lame', 'aac': 'aac', 'vorbis': 'libvorbis'}[self._preferredcodec]
+                       acodec = {'mp3': 'libmp3lame', 'aac': 'aac', 'm4a': 'aac', 'vorbis': 'libvorbis'}[self._preferredcodec]
                        extension = self._preferredcodec
                        more_opts = []
                        if self._preferredquality is not None:
                                more_opts += ['-ab', self._preferredquality]
                        if self._preferredcodec == 'aac':
                                more_opts += ['-f', 'adts']
+                       if self._preferredcodec == 'm4a':
+                               more_opts += ['-absf', 'aac_adtstoasc']
                        if self._preferredcodec == 'vorbis':
                                extension = 'ogg'
 
@@ -4239,7 +4246,7 @@ def parseOpts():
        postproc.add_option('--extract-audio', action='store_true', dest='extractaudio', default=False,
                        help='convert video files to audio-only files (requires ffmpeg and ffprobe)')
        postproc.add_option('--audio-format', metavar='FORMAT', dest='audioformat', default='best',
-                       help='"best", "aac", "vorbis" or "mp3"; best by default')
+                       help='"best", "aac", "vorbis", "mp3", or "m4a"; best by default')
        postproc.add_option('--audio-quality', metavar='QUALITY', dest='audioquality', default='128K',
                        help='ffmpeg audio bitrate specification, 128k by default')
        postproc.add_option('-k', '--keep-video', action='store_true', dest='keepvideo', default=False,
@@ -4385,7 +4392,7 @@ def _real_main():
        except (TypeError, ValueError), err:
                parser.error(u'invalid playlist end number specified')
        if opts.extractaudio:
-               if opts.audioformat not in ['best', 'aac', 'mp3', 'vorbis']:
+               if opts.audioformat not in ['best', 'aac', 'mp3', 'vorbis', 'm4a']:
                        parser.error(u'invalid audio format specified')
 
        # File downloader