Repository: ytdl-org/youtube-dl

Issue:
Please support avconv (from libav) for --extract-audio
--extract-audio currently requires the ffmpeg command-line tool.  Please consider supporting the equivalent avconv tool from the libav project.  The command-line syntax of avconv has evolved a bit from ffmpeg, but still remains quite similar.



Discussion:
avconv is a rename and slightly uncompatible evolution of ffmpeg

Here are the differences
http://libav.org/index.html#fftools_rename

And there I read that ffmpeg is indeed dead, also

> Furthermore, the legacy ffmpeg conversion tool has been removed. Only avconv is available now.

I am for using a cross-compatible syntax and then checking first for avconv and then for ffmpeg as a fallback.


Resolving patch:
diff --git a/youtube_dl/PostProcessor.py b/youtube_dl/PostProcessor.py
--- a/youtube_dl/PostProcessor.py
+++ b/youtube_dl/PostProcessor.py
@@ -60,7 +60,6 @@ def __init__(self, message):
 		self.message = message
 
 class FFmpegExtractAudioPP(PostProcessor):
-
 	def __init__(self, downloader=None, preferredcodec=None, preferredquality=None, keepvideo=False):
 		PostProcessor.__init__(self, downloader)
 		if preferredcodec is None:
@@ -68,11 +67,22 @@ def __init__(self, downloader=None, preferredcodec=None, preferredquality=None,
 		self._preferredcodec = preferredcodec
 		self._preferredquality = preferredquality
 		self._keepvideo = keepvideo
+		self._exes = self.detect_executables()
 
 	@staticmethod
-	def get_audio_codec(path):
+	def detect_executables():
+		available = {'avprobe' : False, 'avconv' : False, 'ffmpeg' : False, 'ffprobe' : False}
+		for path in os.environ["PATH"].split(os.pathsep):
+			for program in available.keys():
+				exe_file = os.path.join(path, program)
+				if os.path.isfile(exe_file) and os.access(exe_file, os.X_OK):
+					available[program] = exe_file
+		return available
+
+	def get_audio_codec(self, path):
+		if not self._exes['ffprobe'] and not self._exes['avprobe']: return None
 		try:
-			cmd = ['ffprobe', '-show_streams', '--', encodeFilename(path)]
+			cmd = [self._exes['avprobe'] or self._exes['ffprobe'], '-show_streams', '--', encodeFilename(path)]
 			handle = subprocess.Popen(cmd, stderr=file(os.path.devnull, 'w'), stdout=subprocess.PIPE)
 			output = handle.communicate()[0]
 			if handle.wait() != 0:
@@ -87,22 +97,18 @@ def get_audio_codec(path):
 				return audio_codec
 		return None
 
-	@staticmethod
-	def run_ffmpeg(path, out_path, codec, more_opts):
+	def run_ffmpeg(self, path, out_path, codec, more_opts):
+		if not self._exes['ffmpeg'] and not self._exes['avconv']:
+			raise AudioConversionError('ffmpeg or avconv not found. Please install one.')	
 		if codec is None:
 			acodec_opts = []
 		else:
 			acodec_opts = ['-acodec', codec]
-		cmd = ['ffmpeg', '-y', '-i', encodeFilename(path), '-vn'] + acodec_opts + more_opts + ['--', encodeFilename(out_path)]
-		try:
-			p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-			stdout,stderr = p.communicate()
-		except (IOError, OSError):
-			e = sys.exc_info()[1]
-			if isinstance(e, OSError) and e.errno == 2:
-				raise AudioConversionError('ffmpeg not found. Please install ffmpeg.')
-			else:
-				raise e
+		cmd = ([self._exes['avconv'] or self._exes['ffmpeg'], '-y', '-i', encodeFilename(path), '-vn']
+			   + acodec_opts + more_opts +
+			   ['--', encodeFilename(out_path)])
+		p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+		stdout,stderr = p.communicate()
 		if p.returncode != 0:
 			msg = stderr.strip().split('\n')[-1]
 			raise AudioConversionError(msg)
@@ -121,7 +127,7 @@ def run(self, information):
 				# Lossless, but in another container
 				acodec = 'copy'
 				extension = self._preferredcodec
-				more_opts = ['-absf', 'aac_adtstoasc']
+				more_opts = [self._exes['avconv'] and '-bsf:a' or '-absf', 'aac_adtstoasc']
 			elif filecodec in ['aac', 'mp3', 'vorbis']:
 				# Lossless if possible
 				acodec = 'copy'
@@ -136,18 +142,18 @@ def run(self, information):
 				extension = 'mp3'
 				more_opts = []
 				if self._preferredquality is not None:
-					more_opts += ['-ab', self._preferredquality]
+					more_opts += [self._exes['avconv'] and '-b:a' or '-ab', self._preferredquality]
 		else:
 			# We convert the audio (lossy)
 			acodec = {'mp3': 'libmp3lame', 'aac': 'aac', 'm4a': 'aac', 'vorbis': 'libvorbis', 'wav': None}[self._preferredcodec]
 			extension = self._preferredcodec
 			more_opts = []
 			if self._preferredquality is not None:
-				more_opts += ['-ab', self._preferredquality]
+				more_opts += [self._exes['avconv'] and '-b:a' or '-ab', self._preferredquality]
 			if self._preferredcodec == 'aac':
 				more_opts += ['-f', 'adts']
 			if self._preferredcodec == 'm4a':
-				more_opts += ['-absf', 'aac_adtstoasc']
+				more_opts += [self._exes['avconv'] and '-bsf:a' or '-absf', 'aac_adtstoasc']
 			if self._preferredcodec == 'vorbis':
 				extension = 'ogg'
 			if self._preferredcodec == 'wav':
@@ -156,7 +162,7 @@ def run(self, information):
 
 		prefix, sep, ext = path.rpartition(u'.') # not os.path.splitext, since the latter does not work on unicode in all setups
 		new_path = prefix + sep + extension
-		self._downloader.to_screen(u'[ffmpeg] Destination: ' + new_path)
+		self._downloader.to_screen(u'[' + self._exes['avconv'] and 'avconv' or 'ffmpeg' + '] Destination: ' + new_path)
 		try:
 			self.run_ffmpeg(path, new_path, acodec, more_opts)
 		except:
@@ -164,7 +170,7 @@ def run(self, information):
 			if isinstance(e, AudioConversionError):
 				self._downloader.to_stderr(u'ERROR: audio conversion failed: ' + e.message)
 			else:
-				self._downloader.to_stderr(u'ERROR: error running ffmpeg')
+				self._downloader.to_stderr(u'ERROR: error running ' + self._exes['avconv'] and 'avconv' or 'ffmpeg')
 			return None
 
  		# Try to update the date time for extracted audio file.
diff --git a/youtube_dl/__init__.py b/youtube_dl/__init__.py
--- a/youtube_dl/__init__.py
+++ b/youtube_dl/__init__.py
@@ -293,11 +293,11 @@ def _find_term_columns():
 
 
 	postproc.add_option('--extract-audio', action='store_true', dest='extractaudio', default=False,
-			help='convert video files to audio-only files (requires ffmpeg and ffprobe)')
+			help='convert video files to audio-only files (requires ffmpeg or avconv and ffprobe or avprobe)')
 	postproc.add_option('--audio-format', metavar='FORMAT', dest='audioformat', default='best',
 			help='"best", "aac", "vorbis", "mp3", "m4a", or "wav"; best by default')
 	postproc.add_option('--audio-quality', metavar='QUALITY', dest='audioquality', default='128K',
-			help='ffmpeg audio bitrate specification, 128k by default')
+			help='ffmpeg/avconv audio bitrate specification, 128k by default')
 	postproc.add_option('-k', '--keep-video', action='store_true', dest='keepvideo', default=False,
 			help='keeps the video file on disk after the post-processing; the video is erased by default')
 


Test patch: