Support arbitrary stream merges

With this change, the merge operator may join any number of media streams,
video or audio. The streams are downloaded in the order specified.

Also, fix the metadata post-processor so that it doesn't leave out
any streams.

youtube_dlc/YoutubeDL.py

@@ -1216,11 +1216,13 @@ class YoutubeDL(object):
                         group = _parse_format_selection(tokens, inside_group=True)
                         current_selector = FormatSelector(GROUP, group, [])
                     elif string == '+':
-                        video_selector = current_selector
-                        audio_selector = _parse_format_selection(tokens, inside_merge=True)
-                        if not video_selector or not audio_selector:
-                            raise syntax_error('"+" must be between two format selectors', start)
-                        current_selector = FormatSelector(MERGE, (video_selector, audio_selector), [])
+                        if not current_selector:
+                            raise syntax_error('Unexpected "+"', start)
+                        selector_1 = current_selector
+                        selector_2 = _parse_format_selection(tokens, inside_merge=True)
+                        if not selector_2:
+                            raise syntax_error('Expected a selector', start)
+                        current_selector = FormatSelector(MERGE, (selector_1, selector_2), [])
                     else:
                         raise syntax_error('Operator not recognized: "{0}"'.format(string), start)
                 elif type == tokenize.ENDMARKER:
@@ -1305,47 +1307,59 @@ class YoutubeDL(object):
                         if matches:
                             yield matches[-1]
             elif selector.type == MERGE:
-                def _merge(formats_info):
-                    format_1, format_2 = [f['format_id'] for f in formats_info]
-                    # The first format must contain the video and the
-                    # second the audio
-                    if formats_info[0].get('vcodec') == 'none':
-                        self.report_error('The first format must '
-                                          'contain the video, try using '
-                                          '"-f %s+%s"' % (format_2, format_1))
-                        return
-                    # Formats must be opposite (video+audio)
-                    if formats_info[0].get('acodec') == 'none' and formats_info[1].get('acodec') == 'none':
-                        self.report_error(
-                            'Both formats %s and %s are video-only, you must specify "-f video+audio"'
-                            % (format_1, format_2))
-                        return
-                    output_ext = (
-                        formats_info[0]['ext']
-                        if self.params.get('merge_output_format') is None
-                        else self.params['merge_output_format'])
-                    return {
+                def _merge(formats_pair):
+                    format_1, format_2 = formats_pair
+
+                    formats_info = []
+                    formats_info.extend(format_1.get('requested_formats', (format_1,)))
+                    formats_info.extend(format_2.get('requested_formats', (format_2,)))
+
+                    video_fmts = [fmt_info for fmt_info in formats_info if fmt_info.get('vcodec') != 'none']
+                    audio_fmts = [fmt_info for fmt_info in formats_info if fmt_info.get('acodec') != 'none']
+
+                    the_only_video = video_fmts[0] if len(video_fmts) == 1 else None
+                    the_only_audio = audio_fmts[0] if len(audio_fmts) == 1 else None
+
+                    output_ext = self.params.get('merge_output_format')
+                    if not output_ext:
+                        if the_only_video:
+                            output_ext = the_only_video['ext']
+                        elif the_only_audio and not video_fmts:
+                            output_ext = the_only_audio['ext']
+                        else:
+                            output_ext = 'mkv'
+
+                    new_dict = {
                         'requested_formats': formats_info,
-                        'format': '%s+%s' % (formats_info[0].get('format'),
-                                             formats_info[1].get('format')),
-                        'format_id': '%s+%s' % (formats_info[0].get('format_id'),
-                                                formats_info[1].get('format_id')),
-                        'width': formats_info[0].get('width'),
-                        'height': formats_info[0].get('height'),
-                        'resolution': formats_info[0].get('resolution'),
-                        'fps': formats_info[0].get('fps'),
-                        'vcodec': formats_info[0].get('vcodec'),
-                        'vbr': formats_info[0].get('vbr'),
-                        'stretched_ratio': formats_info[0].get('stretched_ratio'),
-                        'acodec': formats_info[1].get('acodec'),
-                        'abr': formats_info[1].get('abr'),
+                        'format': '+'.join(fmt_info.get('format') for fmt_info in formats_info),
+                        'format_id': '+'.join(fmt_info.get('format_id') for fmt_info in formats_info),
                         'ext': output_ext,
                     }
-                video_selector, audio_selector = map(_build_selector_function, selector.selector)
+
+                    if the_only_video:
+                        new_dict.update({
+                            'width': the_only_video.get('width'),
+                            'height': the_only_video.get('height'),
+                            'resolution': the_only_video.get('resolution'),
+                            'fps': the_only_video.get('fps'),
+                            'vcodec': the_only_video.get('vcodec'),
+                            'vbr': the_only_video.get('vbr'),
+                            'stretched_ratio': the_only_video.get('stretched_ratio'),
+                        })
+
+                    if the_only_audio:
+                        new_dict.update({
+                            'acodec': the_only_audio.get('acodec'),
+                            'abr': the_only_audio.get('abr'),
+                        })
+
+                    return new_dict
+
+                selector_1, selector_2 = map(_build_selector_function, selector.selector)
 
                 def selector_function(ctx):
                     for pair in itertools.product(
-                            video_selector(copy.deepcopy(ctx)), audio_selector(copy.deepcopy(ctx))):
+                            selector_1(copy.deepcopy(ctx)), selector_2(copy.deepcopy(ctx))):
                         yield _merge(pair)
 
             filters = [self._build_format_filter(f) for f in selector.filters]
@@ -1875,17 +1889,21 @@ class YoutubeDL(object):
                         postprocessors = [merger]
 
                     def compatible_formats(formats):
-                        video, audio = formats
+                        # TODO: some formats actually allow this (mkv, webm, ogg, mp4), but not all of them.
+                        video_formats = [format for format in formats if format.get('vcodec') != 'none']
+                        audio_formats = [format for format in formats if format.get('acodec') != 'none']
+                        if len(video_formats) > 2 or len(audio_formats) > 2:
+                            return False
+
                         # Check extension
-                        video_ext, audio_ext = video.get('ext'), audio.get('ext')
-                        if video_ext and audio_ext:
-                            COMPATIBLE_EXTS = (
-                                ('mp3', 'mp4', 'm4a', 'm4p', 'm4b', 'm4r', 'm4v', 'ismv', 'isma'),
-                                ('webm')
-                            )
-                            for exts in COMPATIBLE_EXTS:
-                                if video_ext in exts and audio_ext in exts:
-                                    return True
+                        exts = set(format.get('ext') for format in formats)
+                        COMPATIBLE_EXTS = (
+                            set(('mp3', 'mp4', 'm4a', 'm4p', 'm4b', 'm4r', 'm4v', 'ismv', 'isma')),
+                            set(('webm',)),
+                        )
+                        for ext_sets in COMPATIBLE_EXTS:
+                            if ext_sets.issuperset(exts):
+                                return True
                         # TODO: Check acodec/vcodec
                         return False
 
@@ -2064,7 +2082,7 @@ class YoutubeDL(object):
             except PostProcessingError as e:
                 self.report_error(e.msg)
             if files_to_delete and not self.params.get('keepvideo', False):
-                for old_filename in files_to_delete:
+                for old_filename in set(files_to_delete):
                     self.to_screen('Deleting original file %s (pass -k to keep)' % old_filename)
                     try:
                         os.remove(encodeFilename(old_filename))

youtube_dlc/postprocessor/ffmpeg.py

@@ -476,7 +476,7 @@ class FFmpegMetadataPP(FFmpegPostProcessor):
         filename = info['filepath']
         temp_filename = prepend_extension(filename, 'temp')
         in_filenames = [filename]
-        options = []
+        options = ['-map', '0']
 
         if info['ext'] == 'm4a':
             options.extend(['-vn', '-acodec', 'copy'])
@@ -518,7 +518,12 @@ class FFmpegMergerPP(FFmpegPostProcessor):
     def run(self, info):
         filename = info['filepath']
         temp_filename = prepend_extension(filename, 'temp')
-        args = ['-c', 'copy', '-map', '0:v:0', '-map', '1:a:0']
+        args = ['-c', 'copy']
+        for (i, fmt) in enumerate(info['requested_formats']):
+            if fmt.get('acodec') != 'none':
+                args.extend(['-map', '%u:a:0' % (i)])
+            if fmt.get('vcodec') != 'none':
+                args.extend(['-map', '%u:v:0' % (i)])
         self._downloader.to_screen('[ffmpeg] Merging formats into "%s"' % filename)
         self.run_ffmpeg_multiple_files(info['__files_to_merge'], temp_filename, args)
         os.rename(encodeFilename(temp_filename), encodeFilename(filename))