-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-
import os
import subprocess
import sys
import time
-from utils import *
+from .utils import *
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.
-
- When this method returns None, the postprocessing chain is
- stopped. However, this method may return an information
- dictionary that will be passed to the next postprocessing
- object in the chain. It can be the one it received after
- changing some fields.
-
- In addition, this method may raise a PostProcessingError
- exception that will be taken into account by the downloader
- it was called from.
- """
- return information # by default, do nothing
-
-class AudioConversionError(BaseException):
- 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:
- preferredcodec = 'best'
- self._preferredcodec = preferredcodec
- self._preferredquality = preferredquality
- self._keepvideo = keepvideo
- self._exes = self.detect_executables()
-
- @staticmethod
- 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 = [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:
- return None
- except (IOError, OSError):
- return None
- audio_codec = None
- for line in output.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]
- 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)
-
- def run(self, information):
- path = information['filepath']
-
- filecodec = self.get_audio_codec(path)
- if filecodec is None:
- self._downloader.to_stderr(u'WARNING: unable to obtain file audio codec with ffprobe')
- return None
-
- more_opts = []
- 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 = [self._exes['avconv'] and '-bsf:a' or '-absf', 'aac_adtstoasc']
- elif filecodec in ['aac', 'mp3', 'vorbis']:
- # 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:
- 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 += [self._exes['avconv'] and '-b:a' or '-ab', self._preferredquality]
- 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
- 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:
- etype,e,tb = sys.exc_info()
- if isinstance(e, AudioConversionError):
- self._downloader.to_stderr(u'ERROR: audio conversion failed: ' + e.message)
- else:
- 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.
- if information.get('filetime') is not None:
- try:
- os.utime(encodeFilename(new_path), (time.time(), information['filetime']))
- except:
- self._downloader.to_stderr(u'WARNING: Cannot update utime of audio file')
-
- if not self._keepvideo:
- try:
- os.remove(encodeFilename(path))
- except (IOError, OSError):
- self._downloader.to_stderr(u'WARNING: Unable to remove downloaded video file')
- return None
-
- information['filepath'] = new_path
- return information
+ """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)])
+ cmd = ([self._exes['avconv'] or self._exes['ffmpeg'], '-y'] + files_cmd
+ + opts +
+ [encodeFilename(self._ffmpeg_filename_argument(out_path))])
+
+ 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))]
+ 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:
+ 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']
+ 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
Rapsys Git / youtubedl / blobdiff