]> jfr.im git - yt-dlp.git/blobdiff - yt_dlp/postprocessor/ffmpeg.py
[docs,cleanup] Some minor refactoring and improve docs
[yt-dlp.git] / yt_dlp / postprocessor / ffmpeg.py
index 7d0452dbc2063500e46a8836f08f0e527e696c98..311170920c5f6435060bc13446aee04a7ff99892 100644 (file)
@@ -1,30 +1,32 @@
 from __future__ import unicode_literals
 
 import io
+import itertools
 import os
 import subprocess
 import time
 import re
 import json
 
-
 from .common import AudioConversionError, PostProcessor
 
-from ..compat import compat_str
+from ..compat import compat_str, compat_numeric_types
 from ..utils import (
+    dfxp2srt,
     encodeArgument,
     encodeFilename,
+    float_or_none,
     get_exe_version,
     is_outdated_version,
+    ISO639Utils,
+    orderedSet,
     PostProcessingError,
     prepend_extension,
-    shell_quote,
-    subtitles_filename,
-    dfxp2srt,
-    ISO639Utils,
     process_communicate_or_kill,
     replace_extension,
-    traverse_dict,
+    shell_quote,
+    traverse_obj,
+    variadic,
 )
 
 
@@ -62,7 +64,7 @@ def __init__(self, downloader=None):
 
     def check_version(self):
         if not self.available:
-            raise FFmpegPostProcessorError('ffmpeg not found. Please install')
+            raise FFmpegPostProcessorError('ffmpeg not found. Please install or provide the path using --ffmpeg-location')
 
         required_version = '10-0' if self.basename == 'avconv' else '1.0'
         if is_outdated_version(
@@ -108,21 +110,19 @@ def get_ffmpeg_version(path):
                         'Continuing without ffmpeg.' % (location))
                     self._versions = {}
                     return
-                elif not os.path.isdir(location):
+                elif os.path.isdir(location):
+                    dirname, basename = location, None
+                else:
                     basename = os.path.splitext(os.path.basename(location))[0]
-                    if basename not in programs:
-                        self.report_warning(
-                            'Cannot identify executable %s, its basename should be one of %s. '
-                            'Continuing without ffmpeg.' %
-                            (location, ', '.join(programs)))
-                        self._versions = {}
-                        return None
-                    location = os.path.dirname(os.path.abspath(location))
+                    basename = next((p for p in programs if basename.startswith(p)), 'ffmpeg')
+                    dirname = os.path.dirname(os.path.abspath(location))
                     if basename in ('ffmpeg', 'ffprobe'):
                         prefer_ffmpeg = True
 
                 self._paths = dict(
-                    (p, os.path.join(location, p)) for p in programs)
+                    (p, os.path.join(dirname, p)) for p in programs)
+                if basename:
+                    self._paths[basename] = location
                 self._versions = dict(
                     (p, get_ffmpeg_version(self._paths[p])) for p in programs)
         if self._versions is None:
@@ -166,7 +166,7 @@ def probe_executable(self):
 
     def get_audio_codec(self, path):
         if not self.probe_available and not self.available:
-            raise PostProcessingError('ffprobe and ffmpeg not found. Please install')
+            raise PostProcessingError('ffprobe and ffmpeg not found. Please install or provide the path using --ffmpeg-location')
         try:
             if self.probe_available:
                 cmd = [
@@ -208,7 +208,7 @@ def get_metadata_object(self, path, opts=[]):
         if self.probe_basename != 'ffprobe':
             if self.probe_available:
                 self.report_warning('Only ffprobe is supported for metadata extraction')
-            raise PostProcessingError('ffprobe not found. Please install.')
+            raise PostProcessingError('ffprobe not found. Please install or provide the path using --ffmpeg-location')
         self.check_version()
 
         cmd = [
@@ -230,22 +230,39 @@ def get_metadata_object(self, path, opts=[]):
     def get_stream_number(self, path, keys, value):
         streams = self.get_metadata_object(path)['streams']
         num = next(
-            (i for i, stream in enumerate(streams) if traverse_dict(stream, keys, casesense=False) == value),
+            (i for i, stream in enumerate(streams) if traverse_obj(stream, keys, casesense=False) == value),
             None)
         return num, len(streams)
 
-    def run_ffmpeg_multiple_files(self, input_paths, out_path, opts):
+    def _get_real_video_duration(self, info, fatal=True):
+        try:
+            if '_real_duration' not in info:
+                info['_real_duration'] = float_or_none(
+                    traverse_obj(self.get_metadata_object(info['filepath']), ('format', 'duration')))
+            if not info['_real_duration']:
+                raise PostProcessingError('ffprobe returned empty duration')
+        except PostProcessingError as e:
+            if fatal:
+                raise PostProcessingError(f'Unable to determine video duration; {e}')
+        return info.setdefault('_real_duration', None)
+
+    def _duration_mismatch(self, d1, d2):
+        if not d1 or not d2:
+            return None
+        return abs(d1 - d2) > 1
+
+    def run_ffmpeg_multiple_files(self, input_paths, out_path, opts, **kwargs):
         return self.real_run_ffmpeg(
             [(path, []) for path in input_paths],
-            [(out_path, opts)])
+            [(out_path, opts)], **kwargs)
 
-    def real_run_ffmpeg(self, input_path_opts, output_path_opts):
+    def real_run_ffmpeg(self, input_path_opts, output_path_opts, *, expected_retcodes=(0,)):
         self.check_version()
 
         oldest_mtime = min(
-            os.stat(encodeFilename(path)).st_mtime for path, _ in input_path_opts)
+            os.stat(encodeFilename(path)).st_mtime for path, _ in input_path_opts if path)
 
-        cmd = [encodeFilename(self.executable, True), encodeArgument('-y')]
+        cmd = [encodeFilename(self.executable, True), encodeArgument('-y'), encodeArgument('-probesize'), encodeArgument('max')]
         # avconv does not have repeat option
         if self.basename == 'ffmpeg':
             cmd += [encodeArgument('-loglevel'), encodeArgument('repeat+info')]
@@ -262,25 +279,27 @@ def make_args(file, args, name, number):
                 + [encodeFilename(self._ffmpeg_filename_argument(file), True)])
 
         for arg_type, path_opts in (('i', input_path_opts), ('o', output_path_opts)):
-            cmd += [arg for i, o in enumerate(path_opts)
-                    for arg in make_args(o[0], o[1], arg_type, i + 1)]
+            cmd += itertools.chain.from_iterable(
+                make_args(path, list(opts), arg_type, i + 1)
+                for i, (path, opts) in enumerate(path_opts) if path)
 
         self.write_debug('ffmpeg command line: %s' % shell_quote(cmd))
         p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
         stdout, stderr = process_communicate_or_kill(p)
-        if p.returncode != 0:
+        if p.returncode not in variadic(expected_retcodes):
             stderr = stderr.decode('utf-8', 'replace').strip()
-            if self.get_param('verbose', False):
-                self.report_error(stderr)
+            self.write_debug(stderr)
             raise FFmpegPostProcessorError(stderr.split('\n')[-1])
         for out_path, _ in output_path_opts:
-            self.try_utime(out_path, oldest_mtime, oldest_mtime)
+            if out_path:
+                self.try_utime(out_path, oldest_mtime, oldest_mtime)
         return stderr.decode('utf-8', 'replace')
 
-    def run_ffmpeg(self, path, out_path, opts):
-        return self.run_ffmpeg_multiple_files([path], out_path, opts)
+    def run_ffmpeg(self, path, out_path, opts, **kwargs):
+        return self.run_ffmpeg_multiple_files([path], out_path, opts, **kwargs)
 
-    def _ffmpeg_filename_argument(self, fn):
+    @staticmethod
+    def _ffmpeg_filename_argument(fn):
         # Always use 'file:' because the filename may contain ':' (ffmpeg
         # interprets that as a protocol) or can start with '-' (-- is broken in
         # ffmpeg, see https://ffmpeg.org/trac/ffmpeg/ticket/2127 for details)
@@ -289,15 +308,70 @@ def _ffmpeg_filename_argument(self, fn):
             return fn
         return 'file:' + fn if fn != '-' else fn
 
+    @staticmethod
+    def _quote_for_ffmpeg(string):
+        # See https://ffmpeg.org/ffmpeg-utils.html#toc-Quoting-and-escaping
+        # A sequence of '' produces '\'''\'';
+        # final replace removes the empty '' between \' \'.
+        string = string.replace("'", r"'\''").replace("'''", "'")
+        # Handle potential ' at string boundaries.
+        string = string[1:] if string[0] == "'" else "'" + string
+        return string[:-1] if string[-1] == "'" else string + "'"
+
+    def force_keyframes(self, filename, timestamps):
+        timestamps = orderedSet(timestamps)
+        if timestamps[0] == 0:
+            timestamps = timestamps[1:]
+        keyframe_file = prepend_extension(filename, 'keyframes.temp')
+        self.to_screen(f'Re-encoding "{filename}" with appropriate keyframes')
+        self.run_ffmpeg(filename, keyframe_file, ['-force_key_frames', ','.join(
+            f'{t:.6f}' for t in timestamps)])
+        return keyframe_file
+
+    def concat_files(self, in_files, out_file, concat_opts=None):
+        """
+        Use concat demuxer to concatenate multiple files having identical streams.
+
+        Only inpoint, outpoint, and duration concat options are supported.
+        See https://ffmpeg.org/ffmpeg-formats.html#concat-1 for details
+        """
+        concat_file = f'{out_file}.concat'
+        self.write_debug(f'Writing concat spec to {concat_file}')
+        with open(concat_file, 'wt', encoding='utf-8') as f:
+            f.writelines(self._concat_spec(in_files, concat_opts))
+
+        out_flags = ['-c', 'copy']
+        if out_file.rpartition('.')[-1] in ('mp4', 'mov'):
+            # For some reason, '-c copy' is not enough to copy subtitles
+            out_flags.extend(['-c:s', 'mov_text', '-movflags', '+faststart'])
+
+        try:
+            self.real_run_ffmpeg(
+                [(concat_file, ['-hide_banner', '-nostdin', '-f', 'concat', '-safe', '0'])],
+                [(out_file, out_flags)])
+        finally:
+            os.remove(concat_file)
+
+    @classmethod
+    def _concat_spec(cls, in_files, concat_opts=None):
+        if concat_opts is None:
+            concat_opts = [{}] * len(in_files)
+        yield 'ffconcat version 1.0\n'
+        for file, opts in zip(in_files, concat_opts):
+            yield f'file {cls._quote_for_ffmpeg(cls._ffmpeg_filename_argument(file))}\n'
+            # Iterate explicitly to yield the following directives in order, ignoring the rest.
+            for directive in 'inpoint', 'outpoint', 'duration':
+                if directive in opts:
+                    yield f'{directive} {opts[directive]}\n'
+
 
 class FFmpegExtractAudioPP(FFmpegPostProcessor):
-    COMMON_AUDIO_EXTENSIONS = ('wav', 'flac', 'm4a', 'aiff', 'mp3', 'ogg', 'mka', 'opus', 'wma')
+    COMMON_AUDIO_EXTS = ('wav', 'flac', 'm4a', 'aiff', 'mp3', 'ogg', 'mka', 'opus', 'wma')
+    SUPPORTED_EXTS = ('best', 'aac', 'flac', 'mp3', 'm4a', 'opus', 'vorbis', 'wav')
 
     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._preferredcodec = preferredcodec or 'best'
         self._preferredquality = preferredquality
         self._nopostoverwrites = nopostoverwrites
 
@@ -312,11 +386,12 @@ def run_ffmpeg(self, path, out_path, codec, more_opts):
         except FFmpegPostProcessorError as err:
             raise AudioConversionError(err.msg)
 
+    @PostProcessor._restrict_to(images=False)
     def run(self, information):
         path = information['filepath']
         orig_ext = information['ext']
 
-        if self._preferredcodec == 'best' and orig_ext in self.COMMON_AUDIO_EXTENSIONS:
+        if self._preferredcodec == 'best' and orig_ext in self.COMMON_AUDIO_EXTS:
             self.to_screen('Skipping audio extraction since the file is already in a common audio format')
             return [], information
 
@@ -400,62 +475,57 @@ def run(self, information):
         return [path], information
 
 
-class FFmpegVideoRemuxerPP(FFmpegPostProcessor):
+class FFmpegVideoConvertorPP(FFmpegPostProcessor):
+    SUPPORTED_EXTS = ('mp4', 'mkv', 'flv', 'webm', 'mov', 'avi', 'mp3', 'mka', 'm4a', 'ogg', 'opus')
+    FORMAT_RE = re.compile(r'{0}(?:/{0})*$'.format(r'(?:\w+>)?(?:%s)' % '|'.join(SUPPORTED_EXTS)))
+    _ACTION = 'converting'
+
     def __init__(self, downloader=None, preferedformat=None):
-        super(FFmpegVideoRemuxerPP, self).__init__(downloader)
+        super(FFmpegVideoConvertorPP, self).__init__(downloader)
         self._preferedformats = preferedformat.lower().split('/')
 
-    def run(self, information):
-        path = information['filepath']
-        sourceext, targetext = information['ext'].lower(), None
+    def _target_ext(self, source_ext):
         for pair in self._preferedformats:
             kv = pair.split('>')
-            if len(kv) == 1 or kv[0].strip() == sourceext:
-                targetext = kv[-1].strip()
-                break
+            if len(kv) == 1 or kv[0].strip() == source_ext:
+                return kv[-1].strip()
 
+    @staticmethod
+    def _options(target_ext):
+        if target_ext == 'avi':
+            return ['-c:v', 'libxvid', '-vtag', 'XVID']
+        return []
+
+    @PostProcessor._restrict_to(images=False)
+    def run(self, info):
+        filename, source_ext = info['filepath'], info['ext'].lower()
+        target_ext = self._target_ext(source_ext)
         _skip_msg = (
-            'could not find a mapping for %s' if not targetext
-            else 'already is in target format %s' if sourceext == targetext
+            f'could not find a mapping for {source_ext}' if not target_ext
+            else f'already is in target format {source_ext}' if source_ext == target_ext
             else None)
         if _skip_msg:
-            self.to_screen('Not remuxing media file %s; %s' % (path, _skip_msg % sourceext))
-            return [], information
+            self.to_screen(f'Not {self._ACTION} media file {filename!r}; {_skip_msg}')
+            return [], info
 
-        options = ['-c', 'copy', '-map', '0', '-dn']
-        if targetext in ['mp4', 'm4a', 'mov']:
-            options.extend(['-movflags', '+faststart'])
-        prefix, sep, oldext = path.rpartition('.')
-        outpath = prefix + sep + targetext
-        self.to_screen('Remuxing video from %s to %s; Destination: %s' % (sourceext, targetext, outpath))
-        self.run_ffmpeg(path, outpath, options)
-        information['filepath'] = outpath
-        information['format'] = targetext
-        information['ext'] = targetext
-        return [path], information
+        outpath = replace_extension(filename, target_ext, source_ext)
+        self.to_screen(f'{self._ACTION.title()} video from {source_ext} to {target_ext}; Destination: {outpath}')
+        self.run_ffmpeg(filename, outpath, self._options(target_ext))
 
+        info['filepath'] = outpath
+        info['format'] = info['ext'] = target_ext
+        return [filename], info
 
-class FFmpegVideoConvertorPP(FFmpegPostProcessor):
-    def __init__(self, downloader=None, preferedformat=None):
-        super(FFmpegVideoConvertorPP, self).__init__(downloader)
-        self._preferedformat = preferedformat
 
-    def run(self, information):
-        path = information['filepath']
-        if information['ext'] == self._preferedformat:
-            self.to_screen('Not converting video file %s - already is in target format %s' % (path, self._preferedformat))
-            return [], information
-        options = []
-        if self._preferedformat == 'avi':
-            options.extend(['-c:v', 'libxvid', '-vtag', 'XVID'])
-        prefix, sep, ext = path.rpartition('.')
-        outpath = prefix + sep + self._preferedformat
-        self.to_screen('Converting video from %s to %s, Destination: ' % (information['ext'], self._preferedformat) + outpath)
-        self.run_ffmpeg(path, outpath, options)
-        information['filepath'] = outpath
-        information['format'] = self._preferedformat
-        information['ext'] = self._preferedformat
-        return [path], information
+class FFmpegVideoRemuxerPP(FFmpegVideoConvertorPP):
+    _ACTION = 'remuxing'
+
+    @staticmethod
+    def _options(target_ext):
+        options = ['-c', 'copy', '-map', '0', '-dn']
+        if target_ext in ['mp4', 'm4a', 'mov']:
+            options.extend(['-movflags', '+faststart'])
+        return options
 
 
 class FFmpegEmbedSubtitlePP(FFmpegPostProcessor):
@@ -463,6 +533,7 @@ def __init__(self, downloader=None, already_have_subtitle=False):
         super(FFmpegEmbedSubtitlePP, self).__init__(downloader)
         self._already_have_subtitle = already_have_subtitle
 
+    @PostProcessor._restrict_to(images=False)
     def run(self, information):
         if information['ext'] not in ('mp4', 'webm', 'mkv'):
             self.to_screen('Subtitles can only be embedded in mp4, webm or mkv files')
@@ -473,20 +544,27 @@ def run(self, information):
             return [], information
 
         filename = information['filepath']
+        if information.get('duration') and self._duration_mismatch(
+                self._get_real_video_duration(information, False), information['duration']):
+            self.to_screen(f'Skipping {self.pp_key()} since the real and expected durations mismatch')
+            return [], information
 
         ext = information['ext']
-        sub_langs = []
-        sub_filenames = []
+        sub_langs, sub_names, sub_filenames = [], [], []
         webm_vtt_warn = False
         mp4_ass_warn = False
 
         for lang, sub_info in subtitles.items():
+            if not os.path.exists(information.get('filepath', '')):
+                self.report_warning(f'Skipping embedding {lang} subtitle because the file is missing')
+                continue
             sub_ext = sub_info['ext']
             if sub_ext == 'json':
                 self.report_warning('JSON subtitles cannot be embedded')
             elif ext != 'webm' or ext == 'webm' and sub_ext == 'vtt':
                 sub_langs.append(lang)
-                sub_filenames.append(subtitles_filename(filename, lang, sub_ext, ext))
+                sub_names.append(sub_info.get('name'))
+                sub_filenames.append(sub_info['filepath'])
             else:
                 if not webm_vtt_warn and ext == 'webm' and sub_ext != 'vtt':
                     webm_vtt_warn = True
@@ -511,35 +589,88 @@ def run(self, information):
         ]
         if information['ext'] == 'mp4':
             opts += ['-c:s', 'mov_text']
-        for (i, lang) in enumerate(sub_langs):
+        for i, (lang, name) in enumerate(zip(sub_langs, sub_names)):
             opts.extend(['-map', '%d:0' % (i + 1)])
             lang_code = ISO639Utils.short2long(lang) or lang
             opts.extend(['-metadata:s:s:%d' % i, 'language=%s' % lang_code])
+            if name:
+                opts.extend(['-metadata:s:s:%d' % i, 'handler_name=%s' % name,
+                             '-metadata:s:s:%d' % i, 'title=%s' % name])
 
         temp_filename = prepend_extension(filename, 'temp')
         self.to_screen('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))
+        os.replace(temp_filename, filename)
 
         files_to_delete = [] if self._already_have_subtitle else sub_filenames
         return files_to_delete, information
 
 
 class FFmpegMetadataPP(FFmpegPostProcessor):
+
+    def __init__(self, downloader, add_metadata=True, add_chapters=True):
+        FFmpegPostProcessor.__init__(self, downloader)
+        self._add_metadata = add_metadata
+        self._add_chapters = add_chapters
+
+    @staticmethod
+    def _options(target_ext):
+        yield from ('-map', '0', '-dn')
+        if target_ext == 'm4a':
+            yield from ('-vn', '-acodec', 'copy')
+        else:
+            yield from ('-c', 'copy')
+
+    @PostProcessor._restrict_to(images=False)
     def run(self, info):
+        filename, metadata_filename = info['filepath'], None
+        options = []
+        if self._add_chapters and info.get('chapters'):
+            metadata_filename = replace_extension(filename, 'meta')
+            options.extend(self._get_chapter_opts(info['chapters'], metadata_filename))
+        if self._add_metadata:
+            options.extend(self._get_metadata_opts(info))
+
+        if not options:
+            self.to_screen('There isn\'t any metadata to add')
+            return [], info
+
+        temp_filename = prepend_extension(filename, 'temp')
+        self.to_screen('Adding metadata to "%s"' % filename)
+        self.run_ffmpeg_multiple_files(
+            (filename, metadata_filename), temp_filename,
+            itertools.chain(self._options(info['ext']), *options))
+        if metadata_filename:
+            os.remove(metadata_filename)
+        os.replace(temp_filename, filename)
+        return [], info
+
+    @staticmethod
+    def _get_chapter_opts(chapters, metadata_filename):
+        with io.open(metadata_filename, 'wt', encoding='utf-8') as f:
+            def ffmpeg_escape(text):
+                return re.sub(r'([\\=;#\n])', r'\\\1', text)
+
+            metadata_file_content = ';FFMETADATA1\n'
+            for chapter in chapters:
+                metadata_file_content += '[CHAPTER]\nTIMEBASE=1/1000\n'
+                metadata_file_content += 'START=%d\n' % (chapter['start_time'] * 1000)
+                metadata_file_content += 'END=%d\n' % (chapter['end_time'] * 1000)
+                chapter_title = chapter.get('title')
+                if chapter_title:
+                    metadata_file_content += 'title=%s\n' % ffmpeg_escape(chapter_title)
+            f.write(metadata_file_content)
+        yield ('-map_metadata', '1')
+
+    def _get_metadata_opts(self, info):
         metadata = {}
 
         def add(meta_list, info_list=None):
-            if not info_list:
-                info_list = meta_list
-            if not isinstance(meta_list, (list, tuple)):
-                meta_list = (meta_list,)
-            if not isinstance(info_list, (list, tuple)):
-                info_list = (info_list,)
-            for info_f in info_list:
-                if info.get(info_f) is not None:
-                    for meta_f in meta_list:
+            if not meta_list:
+                return
+            for info_f in variadic(info_list or meta_list):
+                if isinstance(info.get(info_f), (compat_str, compat_numeric_types)):
+                    for meta_f in variadic(meta_list):
                         metadata[meta_f] = info[info_f]
                     break
 
@@ -551,8 +682,8 @@ def add(meta_list, info_list=None):
 
         add('title', ('track', 'title'))
         add('date', 'upload_date')
-        add(('description', 'comment'), 'description')
-        add('purl', 'webpage_url')
+        add(('description', 'synopsis'), 'description')
+        add(('purl', 'comment'), 'webpage_url')
         add('track', 'track_number')
         add('artist', ('artist', 'creator', 'uploader', 'uploader_id'))
         add('genre')
@@ -564,71 +695,46 @@ def add(meta_list, info_list=None):
         add('episode_id', ('episode', 'episode_id'))
         add('episode_sort', 'episode_number')
 
-        if not metadata:
-            self.to_screen('There isn\'t any metadata to add')
-            return [], info
-
-        filename = info['filepath']
-        temp_filename = prepend_extension(filename, 'temp')
-        in_filenames = [filename]
-        options = ['-map', '0', '-dn']
-
-        if info['ext'] == 'm4a':
-            options.extend(['-vn', '-acodec', 'copy'])
-        else:
-            options.extend(['-c', 'copy'])
-
-        for (name, value) in metadata.items():
-            options.extend(['-metadata', '%s=%s' % (name, value)])
-
-        chapters = info.get('chapters', [])
-        if chapters:
-            metadata_filename = replace_extension(filename, 'meta')
-            with io.open(metadata_filename, 'wt', encoding='utf-8') as f:
-                def ffmpeg_escape(text):
-                    return re.sub(r'(=|;|#|\\|\n)', r'\\\1', text)
-
-                metadata_file_content = ';FFMETADATA1\n'
-                for chapter in chapters:
-                    metadata_file_content += '[CHAPTER]\nTIMEBASE=1/1000\n'
-                    metadata_file_content += 'START=%d\n' % (chapter['start_time'] * 1000)
-                    metadata_file_content += 'END=%d\n' % (chapter['end_time'] * 1000)
-                    chapter_title = chapter.get('title')
-                    if chapter_title:
-                        metadata_file_content += 'title=%s\n' % ffmpeg_escape(chapter_title)
-                f.write(metadata_file_content)
-                in_filenames.append(metadata_filename)
-                options.extend(['-map_metadata', '1'])
-
-        if '__infojson_filename' in info and info['ext'] in ('mkv', 'mka'):
-            old_stream, new_stream = self.get_stream_number(
-                filename, ('tags', 'mimetype'), 'application/json')
+        prefix = 'meta_'
+        for key in filter(lambda k: k.startswith(prefix), info.keys()):
+            add(key[len(prefix):], key)
+
+        for name, value in metadata.items():
+            yield ('-metadata', f'{name}={value}')
+
+        stream_idx = 0
+        for fmt in info.get('requested_formats') or []:
+            stream_count = 2 if 'none' not in (fmt.get('vcodec'), fmt.get('acodec')) else 1
+            if fmt.get('language'):
+                lang = ISO639Utils.short2long(fmt['language']) or fmt['language']
+                for i in range(stream_count):
+                    yield ('-metadata:s:%d' % (stream_idx + i), 'language=%s' % lang)
+            stream_idx += stream_count
+
+        if ('no-attach-info-json' not in self.get_param('compat_opts', [])
+                and '__infojson_filename' in info and info['ext'] in ('mkv', 'mka')):
+            old_stream, new_stream = self.get_stream_number(info['filepath'], ('tags', 'mimetype'), 'application/json')
             if old_stream is not None:
-                options.extend(['-map', '-0:%d' % old_stream])
+                yield ('-map', '-0:%d' % old_stream)
                 new_stream -= 1
 
-            options.extend([
-                '-attach', info['__infojson_filename'],
-                '-metadata:s:%d' % new_stream, 'mimetype=application/json'
-            ])
-
-        self.to_screen('Adding metadata to \'%s\'' % filename)
-        self.run_ffmpeg_multiple_files(in_filenames, temp_filename, options)
-        if chapters:
-            os.remove(metadata_filename)
-        os.remove(encodeFilename(filename))
-        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
-        return [], info
+            yield ('-attach', info['__infojson_filename'],
+                   '-metadata:s:%d' % new_stream, 'mimetype=application/json')
 
 
 class FFmpegMergerPP(FFmpegPostProcessor):
+    @PostProcessor._restrict_to(images=False)
     def run(self, info):
         filename = info['filepath']
         temp_filename = prepend_extension(filename, 'temp')
         args = ['-c', 'copy']
+        audio_streams = 0
         for (i, fmt) in enumerate(info['requested_formats']):
             if fmt.get('acodec') != 'none':
-                args.extend(['-map', '%u:a:0' % (i)])
+                args.extend(['-map', f'{i}:a:0'])
+                if self.get_audio_codec(fmt['filepath']) == 'aac':
+                    args.extend([f'-bsf:a:{audio_streams}', 'aac_adtstoasc'])
+                audio_streams += 1
             if fmt.get('vcodec') != 'none':
                 args.extend(['-map', '%u:v:0' % (i)])
         self.to_screen('Merging formats into "%s"' % filename)
@@ -653,66 +759,82 @@ def can_merge(self):
         return True
 
 
-class FFmpegFixupStretchedPP(FFmpegPostProcessor):
-    def run(self, info):
-        stretched_ratio = info.get('stretched_ratio')
-        if stretched_ratio is None or stretched_ratio == 1:
-            return [], info
-
-        filename = info['filepath']
+class FFmpegFixupPostProcessor(FFmpegPostProcessor):
+    def _fixup(self, msg, filename, options):
         temp_filename = prepend_extension(filename, 'temp')
 
-        options = ['-c', 'copy', '-map', '0', '-dn', '-aspect', '%f' % stretched_ratio]
-        self.to_screen('Fixing aspect ratio in "%s"' % filename)
+        self.to_screen(f'{msg} of "{filename}"')
         self.run_ffmpeg(filename, temp_filename, options)
 
-        os.remove(encodeFilename(filename))
-        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
+        os.replace(temp_filename, filename)
 
+
+class FFmpegFixupStretchedPP(FFmpegFixupPostProcessor):
+    @PostProcessor._restrict_to(images=False, audio=False)
+    def run(self, info):
+        stretched_ratio = info.get('stretched_ratio')
+        if stretched_ratio not in (None, 1):
+            self._fixup('Fixing aspect ratio', info['filepath'], [
+                '-c', 'copy', '-map', '0', '-dn', '-aspect', '%f' % stretched_ratio])
         return [], info
 
 
-class FFmpegFixupM4aPP(FFmpegPostProcessor):
+class FFmpegFixupM4aPP(FFmpegFixupPostProcessor):
+    @PostProcessor._restrict_to(images=False, video=False)
     def run(self, info):
-        if info.get('container') != 'm4a_dash':
-            return [], info
+        if info.get('container') == 'm4a_dash':
+            self._fixup('Correcting container', info['filepath'], [
+                '-c', 'copy', '-map', '0', '-dn', '-f', 'mp4'])
+        return [], info
 
-        filename = info['filepath']
-        temp_filename = prepend_extension(filename, 'temp')
 
-        options = ['-c', 'copy', '-map', '0', '-dn', '-f', 'mp4']
-        self.to_screen('Correcting container in "%s"' % filename)
-        self.run_ffmpeg(filename, temp_filename, options)
+class FFmpegFixupM3u8PP(FFmpegFixupPostProcessor):
+    @PostProcessor._restrict_to(images=False)
+    def run(self, info):
+        if self.get_audio_codec(info['filepath']) == 'aac':
+            self._fixup('Fixing malformed AAC bitstream', info['filepath'], [
+                '-c', 'copy', '-map', '0', '-dn', '-f', 'mp4', '-bsf:a', 'aac_adtstoasc'])
+        return [], info
 
-        os.remove(encodeFilename(filename))
-        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
 
-        return [], info
+class FFmpegFixupTimestampPP(FFmpegFixupPostProcessor):
 
+    def __init__(self, downloader=None, trim=0.001):
+        # "trim" should be used when the video contains unintended packets
+        super(FFmpegFixupTimestampPP, self).__init__(downloader)
+        assert isinstance(trim, (int, float))
+        self.trim = str(trim)
 
-class FFmpegFixupM3u8PP(FFmpegPostProcessor):
+    @PostProcessor._restrict_to(images=False)
     def run(self, info):
-        filename = info['filepath']
-        if self.get_audio_codec(filename) == 'aac':
-            temp_filename = prepend_extension(filename, 'temp')
+        required_version = '4.4'
+        if is_outdated_version(self._versions[self.basename], required_version):
+            self.report_warning(
+                'A re-encode is needed to fix timestamps in older versions of ffmpeg. '
+                f'Please install ffmpeg {required_version} or later to fixup without re-encoding')
+            opts = ['-vf', 'setpts=PTS-STARTPTS']
+        else:
+            opts = ['-c', 'copy', '-bsf', 'setts=ts=TS-STARTPTS']
+        self._fixup('Fixing frame timestamp', info['filepath'], opts + ['-map', '0', '-dn', '-ss', self.trim])
+        return [], info
 
-            options = ['-c', 'copy', '-map', '0', '-dn', '-f', 'mp4', '-bsf:a', 'aac_adtstoasc']
-            self.to_screen('Fixing malformed AAC bitstream in "%s"' % filename)
-            self.run_ffmpeg(filename, temp_filename, options)
 
-            os.remove(encodeFilename(filename))
-            os.rename(encodeFilename(temp_filename), encodeFilename(filename))
+class FFmpegFixupDurationPP(FFmpegFixupPostProcessor):
+    @PostProcessor._restrict_to(images=False)
+    def run(self, info):
+        self._fixup('Fixing video duration', info['filepath'], ['-c', 'copy', '-map', '0', '-dn'])
         return [], info
 
 
 class FFmpegSubtitlesConvertorPP(FFmpegPostProcessor):
+    SUPPORTED_EXTS = ('srt', 'vtt', 'ass', 'lrc')
+
     def __init__(self, downloader=None, format=None):
         super(FFmpegSubtitlesConvertorPP, self).__init__(downloader)
         self.format = format
 
     def run(self, info):
         subs = info.get('requested_subtitles')
-        filename = info['filepath']
         new_ext = self.format
         new_format = new_ext
         if new_format == 'vtt':
@@ -732,9 +854,9 @@ def run(self, info):
                     'You have requested to convert json subtitles into another format, '
                     'which is currently not possible')
                 continue
-            old_file = subtitles_filename(filename, lang, ext, info.get('ext'))
+            old_file = sub['filepath']
             sub_filenames.append(old_file)
-            new_file = subtitles_filename(filename, lang, new_ext, info.get('ext'))
+            new_file = replace_extension(old_file, new_ext)
 
             if ext in ('dfxp', 'ttml', 'tt'):
                 self.report_warning(
@@ -742,7 +864,7 @@ def run(self, info):
                     'which results in style information loss')
 
                 dfxp_file = old_file
-                srt_file = subtitles_filename(filename, lang, 'srt', info.get('ext'))
+                srt_file = replace_extension(old_file, 'srt')
 
                 with open(dfxp_file, 'rb') as f:
                     srt_data = dfxp2srt(f.read())
@@ -753,7 +875,8 @@ def run(self, info):
 
                 subs[lang] = {
                     'ext': 'srt',
-                    'data': srt_data
+                    'data': srt_data,
+                    'filepath': srt_file,
                 }
 
                 if new_ext == 'srt':
@@ -767,12 +890,19 @@ def run(self, info):
                 subs[lang] = {
                     'ext': new_ext,
                     'data': f.read(),
+                    'filepath': new_file,
                 }
 
+            info['__files_to_move'][new_file] = replace_extension(
+                info['__files_to_move'][sub['filepath']], new_ext)
+
         return sub_filenames, info
 
 
 class FFmpegSplitChaptersPP(FFmpegPostProcessor):
+    def __init__(self, downloader, force_keyframes=False):
+        FFmpegPostProcessor.__init__(self, downloader)
+        self._force_keyframes = force_keyframes
 
     def _prepare_filename(self, number, chapter, info):
         info = info.copy()
@@ -789,21 +919,96 @@ def _ffmpeg_args_for_chapter(self, number, chapter, info):
         if not self._downloader._ensure_dir_exists(encodeFilename(destination)):
             return
 
-        chapter['_filename'] = destination
+        chapter['filepath'] = destination
         self.to_screen('Chapter %03d; Destination: %s' % (number, destination))
         return (
             destination,
             ['-ss', compat_str(chapter['start_time']),
-             '-to', compat_str(chapter['end_time'])])
+             '-t', compat_str(chapter['end_time'] - chapter['start_time'])])
 
+    @PostProcessor._restrict_to(images=False)
     def run(self, info):
         chapters = info.get('chapters') or []
         if not chapters:
-            self.report_warning('There are no tracks to extract')
+            self.to_screen('Chapter information is unavailable')
             return [], info
 
+        in_file = info['filepath']
+        if self._force_keyframes and len(chapters) > 1:
+            in_file = self.force_keyframes(in_file, (c['start_time'] for c in chapters))
         self.to_screen('Splitting video by chapters; %d chapters found' % len(chapters))
         for idx, chapter in enumerate(chapters):
             destination, opts = self._ffmpeg_args_for_chapter(idx + 1, chapter, info)
-            self.real_run_ffmpeg([(info['filepath'], opts)], [(destination, ['-c', 'copy'])])
+            self.real_run_ffmpeg([(in_file, opts)], [(destination, ['-c', 'copy'])])
+        if in_file != info['filepath']:
+            os.remove(in_file)
         return [], info
+
+
+class FFmpegThumbnailsConvertorPP(FFmpegPostProcessor):
+    SUPPORTED_EXTS = ('jpg', 'png')
+
+    def __init__(self, downloader=None, format=None):
+        super(FFmpegThumbnailsConvertorPP, self).__init__(downloader)
+        self.format = format
+
+    @staticmethod
+    def is_webp(path):
+        with open(encodeFilename(path), 'rb') as f:
+            b = f.read(12)
+        return b[0:4] == b'RIFF' and b[8:] == b'WEBP'
+
+    def fixup_webp(self, info, idx=-1):
+        thumbnail_filename = info['thumbnails'][idx]['filepath']
+        _, thumbnail_ext = os.path.splitext(thumbnail_filename)
+        if thumbnail_ext:
+            thumbnail_ext = thumbnail_ext[1:].lower()
+            if thumbnail_ext != 'webp' and self.is_webp(thumbnail_filename):
+                self.to_screen('Correcting thumbnail "%s" extension to webp' % thumbnail_filename)
+                webp_filename = replace_extension(thumbnail_filename, 'webp')
+                os.replace(thumbnail_filename, webp_filename)
+                info['thumbnails'][idx]['filepath'] = webp_filename
+                info['__files_to_move'][webp_filename] = replace_extension(
+                    info['__files_to_move'].pop(thumbnail_filename), 'webp')
+
+    @staticmethod
+    def _options(target_ext):
+        if target_ext == 'jpg':
+            return ['-bsf:v', 'mjpeg2jpeg']
+        return []
+
+    def convert_thumbnail(self, thumbnail_filename, target_ext):
+        thumbnail_conv_filename = replace_extension(thumbnail_filename, target_ext)
+
+        self.to_screen('Converting thumbnail "%s" to %s' % (thumbnail_filename, target_ext))
+        self.real_run_ffmpeg(
+            [(thumbnail_filename, ['-f', 'image2', '-pattern_type', 'none'])],
+            [(thumbnail_conv_filename.replace('%', '%%'), self._options(target_ext))])
+        return thumbnail_conv_filename
+
+    def run(self, info):
+        files_to_delete = []
+        has_thumbnail = False
+
+        for idx, thumbnail_dict in enumerate(info['thumbnails']):
+            if 'filepath' not in thumbnail_dict:
+                continue
+            has_thumbnail = True
+            self.fixup_webp(info, idx)
+            original_thumbnail = thumbnail_dict['filepath']
+            _, thumbnail_ext = os.path.splitext(original_thumbnail)
+            if thumbnail_ext:
+                thumbnail_ext = thumbnail_ext[1:].lower()
+            if thumbnail_ext == 'jpeg':
+                thumbnail_ext = 'jpg'
+            if thumbnail_ext == self.format:
+                self.to_screen('Thumbnail "%s" is already in the requested format' % original_thumbnail)
+                continue
+            thumbnail_dict['filepath'] = self.convert_thumbnail(original_thumbnail, self.format)
+            files_to_delete.append(original_thumbnail)
+            info['__files_to_move'][thumbnail_dict['filepath']] = replace_extension(
+                info['__files_to_move'][original_thumbnail], self.format)
+
+        if not has_thumbnail:
+            self.to_screen('There aren\'t any thumbnails to convert')
+        return files_to_delete, info