[YoutubeDL] Add --playlist-items option (Fixes #2662)

AUTHORS

@@ -104,3 +104,4 @@ Ondřej Caletka
 Dinesh S
 Johan K. Jensen
 Yen Chi Hsuan
+Enam Mijbah Noor

youtube_dl/YoutubeDL.py

@@ -137,6 +137,7 @@ class YoutubeDL(object):
     nooverwrites:      Prevent overwriting files.
     playliststart:     Playlist item to start at.
     playlistend:       Playlist item to end at.
+    playlist_items:    Specific indices of playlist to download.
     playlistreverse:   Download playlist items in reverse order.
     matchtitle:        Download only matching titles.
     rejecttitle:       Reject downloads for matching titles.
@@ -703,24 +704,51 @@ class YoutubeDL(object):
             if playlistend == -1:
                 playlistend = None
 
+            playlistitems_str = self.params.get('playlist_items', None)
+            playlistitems = None
+            if playlistitems_str is not None:
+                def iter_playlistitems(format):
+                    for string_segment in format.split(','):
+                        if '-' in string_segment:
+                            start, end = string_segment.split('-')
+                            for item in range(int(start), int(end) + 1):
+                                yield int(item)
+                        else:
+                            yield int(string_segment)
+                playlistitems = iter_playlistitems(playlistitems_str)
+
             ie_entries = ie_result['entries']
             if isinstance(ie_entries, list):
                 n_all_entries = len(ie_entries)
-                entries = ie_entries[playliststart:playlistend]
+                if playlistitems:
+                    entries = [ie_entries[i - 1] for i in playlistitems]
+                else:
+                    entries = ie_entries[playliststart:playlistend]
                 n_entries = len(entries)
                 self.to_screen(
                     "[%s] playlist %s: Collected %d video ids (downloading %d of them)" %
                     (ie_result['extractor'], playlist, n_all_entries, n_entries))
             elif isinstance(ie_entries, PagedList):
-                entries = ie_entries.getslice(
-                    playliststart, playlistend)
+                if playlistitems:
+                    entries = []
+                    for item in playlistitems:
+                        entries.extend(ie_entries.getslice(
+                            item - 1, item
+                        ))
+                else:
+                    entries = ie_entries.getslice(
+                        playliststart, playlistend)
                 n_entries = len(entries)
                 self.to_screen(
                     "[%s] playlist %s: Downloading %d videos" %
                     (ie_result['extractor'], playlist, n_entries))
             else:  # iterable
-                entries = list(itertools.islice(
-                    ie_entries, playliststart, playlistend))
+                if playlistitems:
+                    entry_list = list(ie_entries)
+                    entries = [entry_list[i - 1] for i in playlistitems]
+                else:
+                    entries = list(itertools.islice(
+                        ie_entries, playliststart, playlistend))
                 n_entries = len(entries)
                 self.to_screen(
                     "[%s] playlist %s: Downloading %d videos" %

youtube_dl/__init__.py

@@ -333,6 +333,7 @@ def _real_main(argv=None):
         'sleep_interval': opts.sleep_interval,
         'external_downloader': opts.external_downloader,
         'list_thumbnails': opts.list_thumbnails,
+        'playlist_items': opts.playlist_items,
     }
 
     with YoutubeDL(ydl_opts) as ydl:

youtube_dl/options.py

@@ -200,6 +200,10 @@ def parseOpts(overrideArguments=None):
         '--playlist-end',
         dest='playlistend', metavar='NUMBER', default=None, type=int,
         help='playlist video to end at (default is last)')
+    selection.add_option(
+        '--playlist-items',
+        dest='playlist_items', metavar='ITEM_SPEC', default=None,
+        help='playlist video items to download. Specify indices of the videos in the playlist seperated by commas like: "--playlist-items 1,2,5,8" if you want to download videos indexed 1, 2, 5, 8 in the playlist. You can specify range: "--playlist-items 1-3,7,10-13", it will download the videos at index 1, 2, 3, 7, 10, 11, 12 and 13.')
     selection.add_option(
         '--match-title',
         dest='matchtitle', metavar='REGEX',