Split postprocessor package into multiple modules

4 files changed, 669 insertions, 638 deletions

diff --git a/youtube_dl/postprocessor/__init__.py b/youtube_dl/postprocessor/__init__.py
index 282cc4d7e..7f19f717f 100644
--- a/youtube_dl/postprocessor/__init__.py
+++ b/youtube_dl/postprocessor/__init__.py
@@ -1,640 +1,18 @@
-import os
-import subprocess
-import sys
-import time
 
-
-from ..utils import (
-    compat_subprocess_get_DEVNULL,
-    encodeFilename,
-    hyphenate_date,
-    PostProcessingError,
-    prepend_extension,
-    shell_quote,
-    subtitles_filename,
+from .ffmpeg import (
+    FFmpegMergerPP,
+    FFmpegMetadataPP,
+    FFmpegVideoConvertor,
+    FFmpegExtractAudioPP,
+    FFmpegEmbedSubtitlePP,
 )
-
-
-class PostProcessor(object):
-    """Post Processor class.
-
-    PostProcessor objects can be added to downloaders with their
-    add_post_processor() method. When the downloader has finished a
-    successful download, it will take its internal chain of PostProcessors
-    and start calling the run() method on each one of them, first with
-    an initial argument and then with the returned value of the previous
-    PostProcessor.
-
-    The chain will be stopped if one of them ever returns None or the end
-    of the chain is reached.
-
-    PostProcessor objects follow a "mutual registration" process similar
-    to InfoExtractor objects.
-    """
-
-    _downloader = None
-
-    def __init__(self, downloader=None):
-        self._downloader = downloader
-
-    def set_downloader(self, downloader):
-        """Sets the downloader for this PP."""
-        self._downloader = downloader
-
-    def run(self, information):
-        """Run the PostProcessor.
-
-        The "information" argument is a dictionary like the ones
-        composed by InfoExtractors. The only difference is that this
-        one has an extra field called "filepath" that points to the
-        downloaded file.
-
-        This method returns a tuple, the first element of which describes
-        whether the original file should be kept (i.e. not deleted - None for
-        no preference), and the second of which is the updated information.
-
-        In addition, this method may raise a PostProcessingError
-        exception if post processing fails.
-        """
-        return None, information # by default, keep file and do nothing
-
-class FFmpegPostProcessorError(PostProcessingError):
-    pass
-
-class AudioConversionError(PostProcessingError):
-    pass
-
-
-class FFmpegPostProcessor(PostProcessor):
-    def __init__(self,downloader=None):
-        PostProcessor.__init__(self, downloader)
-        self._exes = self.detect_executables()
-
-    @staticmethod
-    def detect_executables():
-        def executable(exe):
-            try:
-                subprocess.Popen([exe, '-version'], stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()
-            except OSError:
-                return False
-            return exe
-        programs = ['avprobe', 'avconv', 'ffmpeg', 'ffprobe']
-        return dict((program, executable(program)) for program in programs)
-
-    def run_ffmpeg_multiple_files(self, input_paths, out_path, opts):
-        if not self._exes['ffmpeg'] and not self._exes['avconv']:
-            raise FFmpegPostProcessorError(u'ffmpeg or avconv not found. Please install one.')
-
-        files_cmd = []
-        for path in input_paths:
-            files_cmd.extend(['-i', encodeFilename(path, True)])
-        cmd = ([self._exes['avconv'] or self._exes['ffmpeg'], '-y'] + files_cmd
-               + opts +
-               [encodeFilename(self._ffmpeg_filename_argument(out_path), True)])
-
-        if self._downloader.params.get('verbose', False):
-            self._downloader.to_screen(u'[debug] ffmpeg command line: %s' % shell_quote(cmd))
-        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        stdout,stderr = p.communicate()
-        if p.returncode != 0:
-            stderr = stderr.decode('utf-8', 'replace')
-            msg = stderr.strip().split('\n')[-1]
-            raise FFmpegPostProcessorError(msg)
-
-    def run_ffmpeg(self, path, out_path, opts):
-        self.run_ffmpeg_multiple_files([path], out_path, opts)
-
-    def _ffmpeg_filename_argument(self, fn):
-        # ffmpeg broke --, see https://ffmpeg.org/trac/ffmpeg/ticket/2127 for details
-        if fn.startswith(u'-'):
-            return u'./' + fn
-        return fn
-
-
-class FFmpegExtractAudioPP(FFmpegPostProcessor):
-    def __init__(self, downloader=None, preferredcodec=None, preferredquality=None, nopostoverwrites=False):
-        FFmpegPostProcessor.__init__(self, downloader)
-        if preferredcodec is None:
-            preferredcodec = 'best'
-        self._preferredcodec = preferredcodec
-        self._preferredquality = preferredquality
-        self._nopostoverwrites = nopostoverwrites
-
-    def get_audio_codec(self, path):
-        if not self._exes['ffprobe'] and not self._exes['avprobe']:
-            raise PostProcessingError(u'ffprobe or avprobe not found. Please install one.')
-        try:
-            cmd = [
-                self._exes['avprobe'] or self._exes['ffprobe'],
-                '-show_streams',
-                encodeFilename(self._ffmpeg_filename_argument(path), True)]
-            handle = subprocess.Popen(cmd, stderr=compat_subprocess_get_DEVNULL(), stdout=subprocess.PIPE)
-            output = handle.communicate()[0]
-            if handle.wait() != 0:
-                return None
-        except (IOError, OSError):
-            return None
-        audio_codec = None
-        for line in output.decode('ascii', 'ignore').split('\n'):
-            if line.startswith('codec_name='):
-                audio_codec = line.split('=')[1].strip()
-            elif line.strip() == 'codec_type=audio' and audio_codec is not None:
-                return audio_codec
-        return None
-
-    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]
-        opts = ['-vn'] + acodec_opts + more_opts
-        try:
-            FFmpegPostProcessor.run_ffmpeg(self, path, out_path, opts)
-        except FFmpegPostProcessorError as err:
-            raise AudioConversionError(err.msg)
-
-    def run(self, information):
-        path = information['filepath']
-
-        filecodec = self.get_audio_codec(path)
-        if filecodec is None:
-            raise PostProcessingError(u'WARNING: unable to obtain file audio codec with ffprobe')
-
-        more_opts = []
-        if self._preferredcodec == 'best' or self._preferredcodec == filecodec or (self._preferredcodec == 'm4a' and filecodec == 'aac'):
-            if filecodec == 'aac' and self._preferredcodec in ['m4a', 'best']:
-                # Lossless, but in another container
-                acodec = 'copy'
-                extension = 'm4a'
-                more_opts = [self._exes['avconv'] and '-bsf:a' or '-absf', 'aac_adtstoasc']
-            elif filecodec in ['aac', 'mp3', 'vorbis', 'opus']:
-                # Lossless if possible
-                acodec = 'copy'
-                extension = filecodec
-                if filecodec == 'aac':
-                    more_opts = ['-f', 'adts']
-                if filecodec == 'vorbis':
-                    extension = 'ogg'
-            else:
-                # MP3 otherwise.
-                acodec = 'libmp3lame'
-                extension = 'mp3'
-                more_opts = []
-                if self._preferredquality is not None:
-                    if int(self._preferredquality) < 10:
-                        more_opts += [self._exes['avconv'] and '-q:a' or '-aq', self._preferredquality]
-                    else:
-                        more_opts += [self._exes['avconv'] and '-b:a' or '-ab', self._preferredquality + 'k']
-        else:
-            # We convert the audio (lossy)
-            acodec = {'mp3': 'libmp3lame', 'aac': 'aac', 'm4a': 'aac', 'opus': 'opus', 'vorbis': 'libvorbis', 'wav': None}[self._preferredcodec]
-            extension = self._preferredcodec
-            more_opts = []
-            if self._preferredquality is not None:
-                # The opus codec doesn't support the -aq option
-                if int(self._preferredquality) < 10 and extension != 'opus':
-                    more_opts += [self._exes['avconv'] and '-q:a' or '-aq', self._preferredquality]
-                else:
-                    more_opts += [self._exes['avconv'] and '-b:a' or '-ab', self._preferredquality + 'k']
-            if self._preferredcodec == 'aac':
-                more_opts += ['-f', 'adts']
-            if self._preferredcodec == 'm4a':
-                more_opts += [self._exes['avconv'] and '-bsf:a' or '-absf', 'aac_adtstoasc']
-            if self._preferredcodec == 'vorbis':
-                extension = 'ogg'
-            if self._preferredcodec == 'wav':
-                extension = 'wav'
-                more_opts += ['-f', 'wav']
-
-        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
-
-        # If we download foo.mp3 and convert it to... foo.mp3, then don't delete foo.mp3, silly.
-        if new_path == path:
-            self._nopostoverwrites = True
-
-        try:
-            if self._nopostoverwrites and os.path.exists(encodeFilename(new_path)):
-                self._downloader.to_screen(u'[youtube] Post-process file %s exists, skipping' % new_path)
-            else:
-                self._downloader.to_screen(u'[' + (self._exes['avconv'] and 'avconv' or 'ffmpeg') + '] Destination: ' + new_path)
-                self.run_ffmpeg(path, new_path, acodec, more_opts)
-        except:
-            etype,e,tb = sys.exc_info()
-            if isinstance(e, AudioConversionError):
-                msg = u'audio conversion failed: ' + e.msg
-            else:
-                msg = u'error running ' + (self._exes['avconv'] and 'avconv' or 'ffmpeg')
-            raise PostProcessingError(msg)
-
-        # Try to update the date time for extracted audio file.
-        if information.get('filetime') is not None:
-            try:
-                os.utime(encodeFilename(new_path), (time.time(), information['filetime']))
-            except:
-                self._downloader.report_warning(u'Cannot update utime of audio file')
-
-        information['filepath'] = new_path
-        return self._nopostoverwrites,information
-
-
-class FFmpegVideoConvertor(FFmpegPostProcessor):
-    def __init__(self, downloader=None,preferedformat=None):
-        super(FFmpegVideoConvertor, self).__init__(downloader)
-        self._preferedformat=preferedformat
-
-    def run(self, information):
-        path = information['filepath']
-        prefix, sep, ext = path.rpartition(u'.')
-        outpath = prefix + sep + self._preferedformat
-        if information['ext'] == self._preferedformat:
-            self._downloader.to_screen(u'[ffmpeg] Not converting video file %s - already is in target format %s' % (path, self._preferedformat))
-            return True,information
-        self._downloader.to_screen(u'['+'ffmpeg'+'] Converting video from %s to %s, Destination: ' % (information['ext'], self._preferedformat) +outpath)
-        self.run_ffmpeg(path, outpath, [])
-        information['filepath'] = outpath
-        information['format'] = self._preferedformat
-        information['ext'] = self._preferedformat
-        return False,information
-
-
-class FFmpegEmbedSubtitlePP(FFmpegPostProcessor):
-    # See http://www.loc.gov/standards/iso639-2/ISO-639-2_utf-8.txt
-    _lang_map = {
-        'aa': 'aar',
-        'ab': 'abk',
-        'ae': 'ave',
-        'af': 'afr',
-        'ak': 'aka',
-        'am': 'amh',
-        'an': 'arg',
-        'ar': 'ara',
-        'as': 'asm',
-        'av': 'ava',
-        'ay': 'aym',
-        'az': 'aze',
-        'ba': 'bak',
-        'be': 'bel',
-        'bg': 'bul',
-        'bh': 'bih',
-        'bi': 'bis',
-        'bm': 'bam',
-        'bn': 'ben',
-        'bo': 'bod',
-        'br': 'bre',
-        'bs': 'bos',
-        'ca': 'cat',
-        'ce': 'che',
-        'ch': 'cha',
-        'co': 'cos',
-        'cr': 'cre',
-        'cs': 'ces',
-        'cu': 'chu',
-        'cv': 'chv',
-        'cy': 'cym',
-        'da': 'dan',
-        'de': 'deu',
-        'dv': 'div',
-        'dz': 'dzo',
-        'ee': 'ewe',
-        'el': 'ell',
-        'en': 'eng',
-        'eo': 'epo',
-        'es': 'spa',
-        'et': 'est',
-        'eu': 'eus',
-        'fa': 'fas',
-        'ff': 'ful',
-        'fi': 'fin',
-        'fj': 'fij',
-        'fo': 'fao',
-        'fr': 'fra',
-        'fy': 'fry',
-        'ga': 'gle',
-        'gd': 'gla',
-        'gl': 'glg',
-        'gn': 'grn',
-        'gu': 'guj',
-        'gv': 'glv',
-        'ha': 'hau',
-        'he': 'heb',
-        'hi': 'hin',
-        'ho': 'hmo',
-        'hr': 'hrv',
-        'ht': 'hat',
-        'hu': 'hun',
-        'hy': 'hye',
-        'hz': 'her',
-        'ia': 'ina',
-        'id': 'ind',
-        'ie': 'ile',
-        'ig': 'ibo',
-        'ii': 'iii',
-        'ik': 'ipk',
-        'io': 'ido',
-        'is': 'isl',
-        'it': 'ita',
-        'iu': 'iku',
-        'ja': 'jpn',
-        'jv': 'jav',
-        'ka': 'kat',
-        'kg': 'kon',
-        'ki': 'kik',
-        'kj': 'kua',
-        'kk': 'kaz',
-        'kl': 'kal',
-        'km': 'khm',
-        'kn': 'kan',
-        'ko': 'kor',
-        'kr': 'kau',
-        'ks': 'kas',
-        'ku': 'kur',
-        'kv': 'kom',
-        'kw': 'cor',
-        'ky': 'kir',
-        'la': 'lat',
-        'lb': 'ltz',
-        'lg': 'lug',
-        'li': 'lim',
-        'ln': 'lin',
-        'lo': 'lao',
-        'lt': 'lit',
-        'lu': 'lub',
-        'lv': 'lav',
-        'mg': 'mlg',
-        'mh': 'mah',
-        'mi': 'mri',
-        'mk': 'mkd',
-        'ml': 'mal',
-        'mn': 'mon',
-        'mr': 'mar',
-        'ms': 'msa',
-        'mt': 'mlt',
-        'my': 'mya',
-        'na': 'nau',
-        'nb': 'nob',
-        'nd': 'nde',
-        'ne': 'nep',
-        'ng': 'ndo',
-        'nl': 'nld',
-        'nn': 'nno',
-        'no': 'nor',
-        'nr': 'nbl',
-        'nv': 'nav',
-        'ny': 'nya',
-        'oc': 'oci',
-        'oj': 'oji',
-        'om': 'orm',
-        'or': 'ori',
-        'os': 'oss',
-        'pa': 'pan',
-        'pi': 'pli',
-        'pl': 'pol',
-        'ps': 'pus',
-        'pt': 'por',
-        'qu': 'que',
-        'rm': 'roh',
-        'rn': 'run',
-        'ro': 'ron',
-        'ru': 'rus',
-        'rw': 'kin',
-        'sa': 'san',
-        'sc': 'srd',
-        'sd': 'snd',
-        'se': 'sme',
-        'sg': 'sag',
-        'si': 'sin',
-        'sk': 'slk',
-        'sl': 'slv',
-        'sm': 'smo',
-        'sn': 'sna',
-        'so': 'som',
-        'sq': 'sqi',
-        'sr': 'srp',
-        'ss': 'ssw',
-        'st': 'sot',
-        'su': 'sun',
-        'sv': 'swe',
-        'sw': 'swa',
-        'ta': 'tam',
-        'te': 'tel',
-        'tg': 'tgk',
-        'th': 'tha',
-        'ti': 'tir',
-        'tk': 'tuk',
-        'tl': 'tgl',
-        'tn': 'tsn',
-        'to': 'ton',
-        'tr': 'tur',
-        'ts': 'tso',
-        'tt': 'tat',
-        'tw': 'twi',
-        'ty': 'tah',
-        'ug': 'uig',
-        'uk': 'ukr',
-        'ur': 'urd',
-        'uz': 'uzb',
-        've': 'ven',
-        'vi': 'vie',
-        'vo': 'vol',
-        'wa': 'wln',
-        'wo': 'wol',
-        'xh': 'xho',
-        'yi': 'yid',
-        'yo': 'yor',
-        'za': 'zha',
-        'zh': 'zho',
-        'zu': 'zul',
-    }
-
-    def __init__(self, downloader=None, subtitlesformat='srt'):
-        super(FFmpegEmbedSubtitlePP, self).__init__(downloader)
-        self._subformat = subtitlesformat
-
-    @classmethod
-    def _conver_lang_code(cls, code):
-        """Convert language code from ISO 639-1 to ISO 639-2/T"""
-        return cls._lang_map.get(code[:2])
-
-    def run(self, information):
-        if information['ext'] != u'mp4':
-            self._downloader.to_screen(u'[ffmpeg] Subtitles can only be embedded in mp4 files')
-            return True, information
-        if not information.get('subtitles'):
-            self._downloader.to_screen(u'[ffmpeg] There aren\'t any subtitles to embed') 
-            return True, information
-
-        sub_langs = [key for key in information['subtitles']]
-        filename = information['filepath']
-        input_files = [filename] + [subtitles_filename(filename, lang, self._subformat) for lang in sub_langs]
-
-        opts = ['-map', '0:0', '-map', '0:1', '-c:v', 'copy', '-c:a', 'copy']
-        for (i, lang) in enumerate(sub_langs):
-            opts.extend(['-map', '%d:0' % (i+1), '-c:s:%d' % i, 'mov_text'])
-            lang_code = self._conver_lang_code(lang)
-            if lang_code is not None:
-                opts.extend(['-metadata:s:s:%d' % i, 'language=%s' % lang_code])
-        opts.extend(['-f', 'mp4'])
-
-        temp_filename = filename + u'.temp'
-        self._downloader.to_screen(u'[ffmpeg] Embedding subtitles in \'%s\'' % filename)
-        self.run_ffmpeg_multiple_files(input_files, temp_filename, opts)
-        os.remove(encodeFilename(filename))
-        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
-
-        return True, information
-
-
-class FFmpegMetadataPP(FFmpegPostProcessor):
-    def run(self, info):
-        metadata = {}
-        if info.get('title') is not None:
-            metadata['title'] = info['title']
-        if info.get('upload_date') is not None:
-            metadata['date'] = info['upload_date']
-        if info.get('uploader') is not None:
-            metadata['artist'] = info['uploader']
-        elif info.get('uploader_id') is not None:
-            metadata['artist'] = info['uploader_id']
-
-        if not metadata:
-            self._downloader.to_screen(u'[ffmpeg] There isn\'t any metadata to add')
-            return True, info
-
-        filename = info['filepath']
-        temp_filename = prepend_extension(filename, 'temp')
-
-        options = ['-c', 'copy']
-        for (name, value) in metadata.items():
-            options.extend(['-metadata', '%s=%s' % (name, value)])
-
-        self._downloader.to_screen(u'[ffmpeg] Adding metadata to \'%s\'' % filename)
-        self.run_ffmpeg(filename, temp_filename, options)
-        os.remove(encodeFilename(filename))
-        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
-        return True, info
-
-
-class FFmpegMergerPP(FFmpegPostProcessor):
-    def run(self, info):
-        filename = info['filepath']
-        args = ['-c', 'copy']
-        self.run_ffmpeg_multiple_files(info['__files_to_merge'], filename, args)
-        return True, info
-
-
-class XAttrMetadataPP(PostProcessor):
-
-    #
-    # More info about extended attributes for media:
-    #   http://freedesktop.org/wiki/CommonExtendedAttributes/
-    #   http://www.freedesktop.org/wiki/PhreedomDraft/
-    #   http://dublincore.org/documents/usageguide/elements.shtml
-    #
-    # TODO:
-    #  * capture youtube keywords and put them in 'user.dublincore.subject' (comma-separated)
-    #  * figure out which xattrs can be used for 'duration', 'thumbnail', 'resolution'
-    #
-
-    def run(self, info):
-        """ Set extended attributes on downloaded file (if xattr support is found). """
-
-        # This mess below finds the best xattr tool for the job and creates a
-        # "write_xattr" function.
-        try:
-            # try the pyxattr module...
-            import xattr
-            def write_xattr(path, key, value):
-                return xattr.setxattr(path, key, value)
-
-        except ImportError:
-
-            if os.name == 'posix':
-                def which(bin):
-                    for dir in os.environ["PATH"].split(":"):
-                        path = os.path.join(dir, bin)
-                        if os.path.exists(path):
-                            return path
-
-                user_has_setfattr = which("setfattr")
-                user_has_xattr    = which("xattr")
-
-                if user_has_setfattr or user_has_xattr:
-
-                    def write_xattr(path, key, value):
-                        import errno
-                        potential_errors = {
-                            # setfattr: /tmp/blah: Operation not supported
-                            "Operation not supported": errno.EOPNOTSUPP,
-                            # setfattr: ~/blah: No such file or directory
-                            # xattr: No such file: ~/blah
-                            "No such file": errno.ENOENT,
-                        }
-
-                        if user_has_setfattr:
-                            cmd = ['setfattr', '-n', key, '-v', value, path]
-                        elif user_has_xattr:
-                            cmd = ['xattr', '-w', key, value, path]
-
-                        try:
-                            output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
-                        except subprocess.CalledProcessError as e:
-                            errorstr = e.output.strip().decode()
-                            for potential_errorstr, potential_errno in potential_errors.items():
-                                if errorstr.find(potential_errorstr) > -1:
-                                    e = OSError(potential_errno, potential_errorstr)
-                                    e.__cause__ = None
-                                    raise e
-                            raise # Reraise unhandled error
-
-                else:
-                    # On Unix, and can't find pyxattr, setfattr, or xattr.
-                    if sys.platform.startswith('linux'):
-                        self._downloader.report_error("Couldn't find a tool to set the xattrs. Install either the python 'pyxattr' or 'xattr' modules, or the GNU 'attr' package (which contains the 'setfattr' tool).")
-                    elif sys.platform == 'darwin':
-                        self._downloader.report_error("Couldn't find a tool to set the xattrs. Install either the python 'xattr' module, or the 'xattr' binary.")
-            else:
-                # Write xattrs to NTFS Alternate Data Streams: http://en.wikipedia.org/wiki/NTFS#Alternate_data_streams_.28ADS.29
-                def write_xattr(path, key, value):
-                    assert(key.find(":") < 0)
-                    assert(path.find(":") < 0)
-                    assert(os.path.exists(path))
-
-                    ads_fn = path + ":" + key
-                    with open(ads_fn, "w") as f:
-                        f.write(value)
-
-        # Write the metadata to the file's xattrs
-        self._downloader.to_screen('[metadata] Writing metadata to file\'s xattrs...')
-
-        filename = info['filepath']
-
-        try:
-            xattr_mapping = {
-                'user.xdg.referrer.url': 'webpage_url',
-                # 'user.xdg.comment':            'description',
-                'user.dublincore.title': 'title',
-                'user.dublincore.date': 'upload_date',
-                'user.dublincore.description': 'description',
-                'user.dublincore.contributor': 'uploader',
-                'user.dublincore.format': 'format',
-            }
-
-            for xattrname, infoname in xattr_mapping.items():
-
-                value = info.get(infoname)
-
-                if value:
-                    if infoname == "upload_date":
-                        value = hyphenate_date(value)
-
-                    write_xattr(filename, xattrname, value)
-
-            return True, info
-
-        except OSError:
-            self._downloader.report_error("This filesystem doesn't support extended attributes. (You may have to enable them in your /etc/fstab)")
-            return False, info
-
+from .xattrpp import XAttrMetadataPP
+
+__all__ = [
+    'FFmpegMergerPP',
+    'FFmpegMetadataPP',
+    'FFmpegVideoConvertor',
+    'FFmpegExtractAudioPP',
+    'FFmpegEmbedSubtitlePP',
+    'XAttrMetadataPP',
+]
diff --git a/youtube_dl/postprocessor/common.py b/youtube_dl/postprocessor/common.py
new file mode 100644
index 000000000..788f94d02
--- /dev/null
+++ b/youtube_dl/postprocessor/common.py
@@ -0,0 +1,49 @@
+from ..utils import PostProcessingError
+
+
+class PostProcessor(object):
+    """Post Processor class.
+
+    PostProcessor objects can be added to downloaders with their
+    add_post_processor() method. When the downloader has finished a
+    successful download, it will take its internal chain of PostProcessors
+    and start calling the run() method on each one of them, first with
+    an initial argument and then with the returned value of the previous
+    PostProcessor.
+
+    The chain will be stopped if one of them ever returns None or the end
+    of the chain is reached.
+
+    PostProcessor objects follow a "mutual registration" process similar
+    to InfoExtractor objects.
+    """
+
+    _downloader = None
+
+    def __init__(self, downloader=None):
+        self._downloader = downloader
+
+    def set_downloader(self, downloader):
+        """Sets the downloader for this PP."""
+        self._downloader = downloader
+
+    def run(self, information):
+        """Run the PostProcessor.
+
+        The "information" argument is a dictionary like the ones
+        composed by InfoExtractors. The only difference is that this
+        one has an extra field called "filepath" that points to the
+        downloaded file.
+
+        This method returns a tuple, the first element of which describes
+        whether the original file should be kept (i.e. not deleted - None for
+        no preference), and the second of which is the updated information.
+
+        In addition, this method may raise a PostProcessingError
+        exception if post processing fails.
+        """
+        return None, information  # by default, keep file and do nothing
+
+
+class AudioConversionError(PostProcessingError):
+    pass
diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
new file mode 100644
index 000000000..91434d970
--- /dev/null
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -0,0 +1,481 @@
+import os
+import subprocess
+import sys
+import time
+
+
+from .common import AudioConversionError, PostProcessor
+
+from ..utils import (
+    compat_subprocess_get_DEVNULL,
+    encodeFilename,
+    PostProcessingError,
+    prepend_extension,
+    shell_quote,
+    subtitles_filename,
+)
+
+
+
+class FFmpegPostProcessorError(PostProcessingError):
+    pass
+
+class FFmpegPostProcessor(PostProcessor):
+    def __init__(self,downloader=None):
+        PostProcessor.__init__(self, downloader)
+        self._exes = self.detect_executables()
+
+    @staticmethod
+    def detect_executables():
+        def executable(exe):
+            try:
+                subprocess.Popen([exe, '-version'], stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()
+            except OSError:
+                return False
+            return exe
+        programs = ['avprobe', 'avconv', 'ffmpeg', 'ffprobe']
+        return dict((program, executable(program)) for program in programs)
+
+    def run_ffmpeg_multiple_files(self, input_paths, out_path, opts):
+        if not self._exes['ffmpeg'] and not self._exes['avconv']:
+            raise FFmpegPostProcessorError(u'ffmpeg or avconv not found. Please install one.')
+
+        files_cmd = []
+        for path in input_paths:
+            files_cmd.extend(['-i', encodeFilename(path, True)])
+        cmd = ([self._exes['avconv'] or self._exes['ffmpeg'], '-y'] + files_cmd
+               + opts +
+               [encodeFilename(self._ffmpeg_filename_argument(out_path), True)])
+
+        if self._downloader.params.get('verbose', False):
+            self._downloader.to_screen(u'[debug] ffmpeg command line: %s' % shell_quote(cmd))
+        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        stdout,stderr = p.communicate()
+        if p.returncode != 0:
+            stderr = stderr.decode('utf-8', 'replace')
+            msg = stderr.strip().split('\n')[-1]
+            raise FFmpegPostProcessorError(msg)
+
+    def run_ffmpeg(self, path, out_path, opts):
+        self.run_ffmpeg_multiple_files([path], out_path, opts)
+
+    def _ffmpeg_filename_argument(self, fn):
+        # ffmpeg broke --, see https://ffmpeg.org/trac/ffmpeg/ticket/2127 for details
+        if fn.startswith(u'-'):
+            return u'./' + fn
+        return fn
+
+
+class FFmpegExtractAudioPP(FFmpegPostProcessor):
+    def __init__(self, downloader=None, preferredcodec=None, preferredquality=None, nopostoverwrites=False):
+        FFmpegPostProcessor.__init__(self, downloader)
+        if preferredcodec is None:
+            preferredcodec = 'best'
+        self._preferredcodec = preferredcodec
+        self._preferredquality = preferredquality
+        self._nopostoverwrites = nopostoverwrites
+
+    def get_audio_codec(self, path):
+        if not self._exes['ffprobe'] and not self._exes['avprobe']:
+            raise PostProcessingError(u'ffprobe or avprobe not found. Please install one.')
+        try:
+            cmd = [
+                self._exes['avprobe'] or self._exes['ffprobe'],
+                '-show_streams',
+                encodeFilename(self._ffmpeg_filename_argument(path), True)]
+            handle = subprocess.Popen(cmd, stderr=compat_subprocess_get_DEVNULL(), stdout=subprocess.PIPE)
+            output = handle.communicate()[0]
+            if handle.wait() != 0:
+                return None
+        except (IOError, OSError):
+            return None
+        audio_codec = None
+        for line in output.decode('ascii', 'ignore').split('\n'):
+            if line.startswith('codec_name='):
+                audio_codec = line.split('=')[1].strip()
+            elif line.strip() == 'codec_type=audio' and audio_codec is not None:
+                return audio_codec
+        return None
+
+    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]
+        opts = ['-vn'] + acodec_opts + more_opts
+        try:
+            FFmpegPostProcessor.run_ffmpeg(self, path, out_path, opts)
+        except FFmpegPostProcessorError as err:
+            raise AudioConversionError(err.msg)
+
+    def run(self, information):
+        path = information['filepath']
+
+        filecodec = self.get_audio_codec(path)
+        if filecodec is None:
+            raise PostProcessingError(u'WARNING: unable to obtain file audio codec with ffprobe')
+
+        more_opts = []
+        if self._preferredcodec == 'best' or self._preferredcodec == filecodec or (self._preferredcodec == 'm4a' and filecodec == 'aac'):
+            if filecodec == 'aac' and self._preferredcodec in ['m4a', 'best']:
+                # Lossless, but in another container
+                acodec = 'copy'
+                extension = 'm4a'
+                more_opts = [self._exes['avconv'] and '-bsf:a' or '-absf', 'aac_adtstoasc']
+            elif filecodec in ['aac', 'mp3', 'vorbis', 'opus']:
+                # Lossless if possible
+                acodec = 'copy'
+                extension = filecodec
+                if filecodec == 'aac':
+                    more_opts = ['-f', 'adts']
+                if filecodec == 'vorbis':
+                    extension = 'ogg'
+            else:
+                # MP3 otherwise.
+                acodec = 'libmp3lame'
+                extension = 'mp3'
+                more_opts = []
+                if self._preferredquality is not None:
+                    if int(self._preferredquality) < 10:
+                        more_opts += [self._exes['avconv'] and '-q:a' or '-aq', self._preferredquality]
+                    else:
+                        more_opts += [self._exes['avconv'] and '-b:a' or '-ab', self._preferredquality + 'k']
+        else:
+            # We convert the audio (lossy)
+            acodec = {'mp3': 'libmp3lame', 'aac': 'aac', 'm4a': 'aac', 'opus': 'opus', 'vorbis': 'libvorbis', 'wav': None}[self._preferredcodec]
+            extension = self._preferredcodec
+            more_opts = []
+            if self._preferredquality is not None:
+                # The opus codec doesn't support the -aq option
+                if int(self._preferredquality) < 10 and extension != 'opus':
+                    more_opts += [self._exes['avconv'] and '-q:a' or '-aq', self._preferredquality]
+                else:
+                    more_opts += [self._exes['avconv'] and '-b:a' or '-ab', self._preferredquality + 'k']
+            if self._preferredcodec == 'aac':
+                more_opts += ['-f', 'adts']
+            if self._preferredcodec == 'm4a':
+                more_opts += [self._exes['avconv'] and '-bsf:a' or '-absf', 'aac_adtstoasc']
+            if self._preferredcodec == 'vorbis':
+                extension = 'ogg'
+            if self._preferredcodec == 'wav':
+                extension = 'wav'
+                more_opts += ['-f', 'wav']
+
+        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
+
+        # If we download foo.mp3 and convert it to... foo.mp3, then don't delete foo.mp3, silly.
+        if new_path == path:
+            self._nopostoverwrites = True
+
+        try:
+            if self._nopostoverwrites and os.path.exists(encodeFilename(new_path)):
+                self._downloader.to_screen(u'[youtube] Post-process file %s exists, skipping' % new_path)
+            else:
+                self._downloader.to_screen(u'[' + (self._exes['avconv'] and 'avconv' or 'ffmpeg') + '] Destination: ' + new_path)
+                self.run_ffmpeg(path, new_path, acodec, more_opts)
+        except:
+            etype,e,tb = sys.exc_info()
+            if isinstance(e, AudioConversionError):
+                msg = u'audio conversion failed: ' + e.msg
+            else:
+                msg = u'error running ' + (self._exes['avconv'] and 'avconv' or 'ffmpeg')
+            raise PostProcessingError(msg)
+
+        # Try to update the date time for extracted audio file.
+        if information.get('filetime') is not None:
+            try:
+                os.utime(encodeFilename(new_path), (time.time(), information['filetime']))
+            except:
+                self._downloader.report_warning(u'Cannot update utime of audio file')
+
+        information['filepath'] = new_path
+        return self._nopostoverwrites,information
+
+
+class FFmpegVideoConvertor(FFmpegPostProcessor):
+    def __init__(self, downloader=None,preferedformat=None):
+        super(FFmpegVideoConvertor, self).__init__(downloader)
+        self._preferedformat=preferedformat
+
+    def run(self, information):
+        path = information['filepath']
+        prefix, sep, ext = path.rpartition(u'.')
+        outpath = prefix + sep + self._preferedformat
+        if information['ext'] == self._preferedformat:
+            self._downloader.to_screen(u'[ffmpeg] Not converting video file %s - already is in target format %s' % (path, self._preferedformat))
+            return True,information
+        self._downloader.to_screen(u'['+'ffmpeg'+'] Converting video from %s to %s, Destination: ' % (information['ext'], self._preferedformat) +outpath)
+        self.run_ffmpeg(path, outpath, [])
+        information['filepath'] = outpath
+        information['format'] = self._preferedformat
+        information['ext'] = self._preferedformat
+        return False,information
+
+
+class FFmpegEmbedSubtitlePP(FFmpegPostProcessor):
+    # See http://www.loc.gov/standards/iso639-2/ISO-639-2_utf-8.txt
+    _lang_map = {
+        'aa': 'aar',
+        'ab': 'abk',
+        'ae': 'ave',
+        'af': 'afr',
+        'ak': 'aka',
+        'am': 'amh',
+        'an': 'arg',
+        'ar': 'ara',
+        'as': 'asm',
+        'av': 'ava',
+        'ay': 'aym',
+        'az': 'aze',
+        'ba': 'bak',
+        'be': 'bel',
+        'bg': 'bul',
+        'bh': 'bih',
+        'bi': 'bis',
+        'bm': 'bam',
+        'bn': 'ben',
+        'bo': 'bod',
+        'br': 'bre',
+        'bs': 'bos',
+        'ca': 'cat',
+        'ce': 'che',
+        'ch': 'cha',
+        'co': 'cos',
+        'cr': 'cre',
+        'cs': 'ces',
+        'cu': 'chu',
+        'cv': 'chv',
+        'cy': 'cym',
+        'da': 'dan',
+        'de': 'deu',
+        'dv': 'div',
+        'dz': 'dzo',
+        'ee': 'ewe',
+        'el': 'ell',
+        'en': 'eng',
+        'eo': 'epo',
+        'es': 'spa',
+        'et': 'est',
+        'eu': 'eus',
+        'fa': 'fas',
+        'ff': 'ful',
+        'fi': 'fin',
+        'fj': 'fij',
+        'fo': 'fao',
+        'fr': 'fra',
+        'fy': 'fry',
+        'ga': 'gle',
+        'gd': 'gla',
+        'gl': 'glg',
+        'gn': 'grn',
+        'gu': 'guj',
+        'gv': 'glv',
+        'ha': 'hau',
+        'he': 'heb',
+        'hi': 'hin',
+        'ho': 'hmo',
+        'hr': 'hrv',
+        'ht': 'hat',
+        'hu': 'hun',
+        'hy': 'hye',
+        'hz': 'her',
+        'ia': 'ina',
+        'id': 'ind',
+        'ie': 'ile',
+        'ig': 'ibo',
+        'ii': 'iii',
+        'ik': 'ipk',
+        'io': 'ido',
+        'is': 'isl',
+        'it': 'ita',
+        'iu': 'iku',
+        'ja': 'jpn',
+        'jv': 'jav',
+        'ka': 'kat',
+        'kg': 'kon',
+        'ki': 'kik',
+        'kj': 'kua',
+        'kk': 'kaz',
+        'kl': 'kal',
+        'km': 'khm',
+        'kn': 'kan',
+        'ko': 'kor',
+        'kr': 'kau',
+        'ks': 'kas',
+        'ku': 'kur',
+        'kv': 'kom',
+        'kw': 'cor',
+        'ky': 'kir',
+        'la': 'lat',
+        'lb': 'ltz',
+        'lg': 'lug',
+        'li': 'lim',
+        'ln': 'lin',
+        'lo': 'lao',
+        'lt': 'lit',
+        'lu': 'lub',
+        'lv': 'lav',
+        'mg': 'mlg',
+        'mh': 'mah',
+        'mi': 'mri',
+        'mk': 'mkd',
+        'ml': 'mal',
+        'mn': 'mon',
+        'mr': 'mar',
+        'ms': 'msa',
+        'mt': 'mlt',
+        'my': 'mya',
+        'na': 'nau',
+        'nb': 'nob',
+        'nd': 'nde',
+        'ne': 'nep',
+        'ng': 'ndo',
+        'nl': 'nld',
+        'nn': 'nno',
+        'no': 'nor',
+        'nr': 'nbl',
+        'nv': 'nav',
+        'ny': 'nya',
+        'oc': 'oci',
+        'oj': 'oji',
+        'om': 'orm',
+        'or': 'ori',
+        'os': 'oss',
+        'pa': 'pan',
+        'pi': 'pli',
+        'pl': 'pol',
+        'ps': 'pus',
+        'pt': 'por',
+        'qu': 'que',
+        'rm': 'roh',
+        'rn': 'run',
+        'ro': 'ron',
+        'ru': 'rus',
+        'rw': 'kin',
+        'sa': 'san',
+        'sc': 'srd',
+        'sd': 'snd',
+        'se': 'sme',
+        'sg': 'sag',
+        'si': 'sin',
+        'sk': 'slk',
+        'sl': 'slv',
+        'sm': 'smo',
+        'sn': 'sna',
+        'so': 'som',
+        'sq': 'sqi',
+        'sr': 'srp',
+        'ss': 'ssw',
+        'st': 'sot',
+        'su': 'sun',
+        'sv': 'swe',
+        'sw': 'swa',
+        'ta': 'tam',
+        'te': 'tel',
+        'tg': 'tgk',
+        'th': 'tha',
+        'ti': 'tir',
+        'tk': 'tuk',
+        'tl': 'tgl',
+        'tn': 'tsn',
+        'to': 'ton',
+        'tr': 'tur',
+        'ts': 'tso',
+        'tt': 'tat',
+        'tw': 'twi',
+        'ty': 'tah',
+        'ug': 'uig',
+        'uk': 'ukr',
+        'ur': 'urd',
+        'uz': 'uzb',
+        've': 'ven',
+        'vi': 'vie',
+        'vo': 'vol',
+        'wa': 'wln',
+        'wo': 'wol',
+        'xh': 'xho',
+        'yi': 'yid',
+        'yo': 'yor',
+        'za': 'zha',
+        'zh': 'zho',
+        'zu': 'zul',
+    }
+
+    def __init__(self, downloader=None, subtitlesformat='srt'):
+        super(FFmpegEmbedSubtitlePP, self).__init__(downloader)
+        self._subformat = subtitlesformat
+
+    @classmethod
+    def _conver_lang_code(cls, code):
+        """Convert language code from ISO 639-1 to ISO 639-2/T"""
+        return cls._lang_map.get(code[:2])
+
+    def run(self, information):
+        if information['ext'] != u'mp4':
+            self._downloader.to_screen(u'[ffmpeg] Subtitles can only be embedded in mp4 files')
+            return True, information
+        if not information.get('subtitles'):
+            self._downloader.to_screen(u'[ffmpeg] There aren\'t any subtitles to embed') 
+            return True, information
+
+        sub_langs = [key for key in information['subtitles']]
+        filename = information['filepath']
+        input_files = [filename] + [subtitles_filename(filename, lang, self._subformat) for lang in sub_langs]
+
+        opts = ['-map', '0:0', '-map', '0:1', '-c:v', 'copy', '-c:a', 'copy']
+        for (i, lang) in enumerate(sub_langs):
+            opts.extend(['-map', '%d:0' % (i+1), '-c:s:%d' % i, 'mov_text'])
+            lang_code = self._conver_lang_code(lang)
+            if lang_code is not None:
+                opts.extend(['-metadata:s:s:%d' % i, 'language=%s' % lang_code])
+        opts.extend(['-f', 'mp4'])
+
+        temp_filename = filename + u'.temp'
+        self._downloader.to_screen(u'[ffmpeg] Embedding subtitles in \'%s\'' % filename)
+        self.run_ffmpeg_multiple_files(input_files, temp_filename, opts)
+        os.remove(encodeFilename(filename))
+        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
+
+        return True, information
+
+
+class FFmpegMetadataPP(FFmpegPostProcessor):
+    def run(self, info):
+        metadata = {}
+        if info.get('title') is not None:
+            metadata['title'] = info['title']
+        if info.get('upload_date') is not None:
+            metadata['date'] = info['upload_date']
+        if info.get('uploader') is not None:
+            metadata['artist'] = info['uploader']
+        elif info.get('uploader_id') is not None:
+            metadata['artist'] = info['uploader_id']
+
+        if not metadata:
+            self._downloader.to_screen(u'[ffmpeg] There isn\'t any metadata to add')
+            return True, info
+
+        filename = info['filepath']
+        temp_filename = prepend_extension(filename, 'temp')
+
+        options = ['-c', 'copy']
+        for (name, value) in metadata.items():
+            options.extend(['-metadata', '%s=%s' % (name, value)])
+
+        self._downloader.to_screen(u'[ffmpeg] Adding metadata to \'%s\'' % filename)
+        self.run_ffmpeg(filename, temp_filename, options)
+        os.remove(encodeFilename(filename))
+        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
+        return True, info
+
+
+class FFmpegMergerPP(FFmpegPostProcessor):
+    def run(self, info):
+        filename = info['filepath']
+        args = ['-c', 'copy']
+        self.run_ffmpeg_multiple_files(info['__files_to_merge'], filename, args)
+        return True, info
+
diff --git a/youtube_dl/postprocessor/xattrpp.py b/youtube_dl/postprocessor/xattrpp.py
new file mode 100644
index 000000000..440df93ec
--- /dev/null
+++ b/youtube_dl/postprocessor/xattrpp.py
@@ -0,0 +1,123 @@
+import os
+import subprocess
+import sys
+
+from .common import PostProcessor
+from ..utils import (
+    hyphenate_date,
+)
+
+
+class XAttrMetadataPP(PostProcessor):
+
+    #
+    # More info about extended attributes for media:
+    #   http://freedesktop.org/wiki/CommonExtendedAttributes/
+    #   http://www.freedesktop.org/wiki/PhreedomDraft/
+    #   http://dublincore.org/documents/usageguide/elements.shtml
+    #
+    # TODO:
+    #  * capture youtube keywords and put them in 'user.dublincore.subject' (comma-separated)
+    #  * figure out which xattrs can be used for 'duration', 'thumbnail', 'resolution'
+    #
+
+    def run(self, info):
+        """ Set extended attributes on downloaded file (if xattr support is found). """
+
+        # This mess below finds the best xattr tool for the job and creates a
+        # "write_xattr" function.
+        try:
+            # try the pyxattr module...
+            import xattr
+            def write_xattr(path, key, value):
+                return xattr.setxattr(path, key, value)
+
+        except ImportError:
+
+            if os.name == 'posix':
+                def which(bin):
+                    for dir in os.environ["PATH"].split(":"):
+                        path = os.path.join(dir, bin)
+                        if os.path.exists(path):
+                            return path
+
+                user_has_setfattr = which("setfattr")
+                user_has_xattr    = which("xattr")
+
+                if user_has_setfattr or user_has_xattr:
+
+                    def write_xattr(path, key, value):
+                        import errno
+                        potential_errors = {
+                            # setfattr: /tmp/blah: Operation not supported
+                            "Operation not supported": errno.EOPNOTSUPP,
+                            # setfattr: ~/blah: No such file or directory
+                            # xattr: No such file: ~/blah
+                            "No such file": errno.ENOENT,
+                        }
+
+                        if user_has_setfattr:
+                            cmd = ['setfattr', '-n', key, '-v', value, path]
+                        elif user_has_xattr:
+                            cmd = ['xattr', '-w', key, value, path]
+
+                        try:
+                            subprocess.check_output(cmd, stderr=subprocess.STDOUT)
+                        except subprocess.CalledProcessError as e:
+                            errorstr = e.output.strip().decode()
+                            for potential_errorstr, potential_errno in potential_errors.items():
+                                if errorstr.find(potential_errorstr) > -1:
+                                    e = OSError(potential_errno, potential_errorstr)
+                                    e.__cause__ = None
+                                    raise e
+                            raise # Reraise unhandled error
+
+                else:
+                    # On Unix, and can't find pyxattr, setfattr, or xattr.
+                    if sys.platform.startswith('linux'):
+                        self._downloader.report_error("Couldn't find a tool to set the xattrs. Install either the python 'pyxattr' or 'xattr' modules, or the GNU 'attr' package (which contains the 'setfattr' tool).")
+                    elif sys.platform == 'darwin':
+                        self._downloader.report_error("Couldn't find a tool to set the xattrs. Install either the python 'xattr' module, or the 'xattr' binary.")
+            else:
+                # Write xattrs to NTFS Alternate Data Streams: http://en.wikipedia.org/wiki/NTFS#Alternate_data_streams_.28ADS.29
+                def write_xattr(path, key, value):
+                    assert(key.find(":") < 0)
+                    assert(path.find(":") < 0)
+                    assert(os.path.exists(path))
+
+                    ads_fn = path + ":" + key
+                    with open(ads_fn, "w") as f:
+                        f.write(value)
+
+        # Write the metadata to the file's xattrs
+        self._downloader.to_screen('[metadata] Writing metadata to file\'s xattrs...')
+
+        filename = info['filepath']
+
+        try:
+            xattr_mapping = {
+                'user.xdg.referrer.url': 'webpage_url',
+                # 'user.xdg.comment':            'description',
+                'user.dublincore.title': 'title',
+                'user.dublincore.date': 'upload_date',
+                'user.dublincore.description': 'description',
+                'user.dublincore.contributor': 'uploader',
+                'user.dublincore.format': 'format',
+            }
+
+            for xattrname, infoname in xattr_mapping.items():
+
+                value = info.get(infoname)
+
+                if value:
+                    if infoname == "upload_date":
+                        value = hyphenate_date(value)
+
+                    write_xattr(filename, xattrname, value)
+
+            return True, info
+
+        except OSError:
+            self._downloader.report_error("This filesystem doesn't support extended attributes. (You may have to enable them in your /etc/fstab)")
+            return False, info
+