Repository: yt-dlp/yt-dlp
File: yt_dlp/extractor/bbc.py (Python)

Code before:
            playlist = self._download_json(
                'http://www.bbc.co.uk/programmes/%s/playlist.json' % playlist_id,
                playlist_id, 'Downloading playlist JSON')

            version = playlist.get('defaultAvailableVersion')
            if version:
                smp_config = version['smpConfig']
                title = smp_config['title']
                description = smp_config['summary']
                for item in smp_config['items']:
                    kind = item['kind']
                    if kind not in ('programme', 'radioProgramme'):
                        continue
                    programme_id = item.get('vpid')
                    duration = int_or_none(item.get('duration'))
                    formats, subtitles = self._download_media_selector(programme_id)
                return programme_id, title, description, duration, formats, subtitles
        except ExtractorError as ee:
            if not (isinstance(ee.cause, compat_HTTPError) and ee.cause.code == 404):
                raise

        # fallback to legacy playlist
        return self._process_legacy_playlist(playlist_id)

    def _process_legacy_playlist_url(self, url, display_id):
        playlist = self._download_legacy_playlist_url(url, display_id)
        return self._extract_from_legacy_playlist(playlist, display_id)

    def _process_legacy_playlist(self, playlist_id):
        return self._process_legacy_playlist_url(
            'http://www.bbc.co.uk/iplayer/playlist/%s' % playlist_id, playlist_id)

    def _download_legacy_playlist_url(self, url, playlist_id=None):
        return self._download_xml(
            url, playlist_id, 'Downloading legacy playlist XML')

    def _extract_from_legacy_playlist(self, playlist, playlist_id):
        no_items = playlist.find('./{%s}noItems' % self._EMP_PLAYLIST_NS)
        if no_items is not None:
            reason = no_items.get('reason')
            if reason == 'preAvailability':
                msg = 'Episode %s is not yet available' % playlist_id
            elif reason == 'postAvailability':
                msg = 'Episode %s is no longer available' % playlist_id
            elif reason == 'noMedia':
                msg = 'Episode %s is not currently available' % playlist_id
            else:
                msg = 'Episode %s is not available: %s' % (playlist_id, reason)
            raise ExtractorError(msg, expected=True)

        for item in self._extract_items(playlist):

Review comment (suggestion):
```suggestion
                        subtitles.setdefault(tag, []).extend(subformats)
```

Code after:
            playlist = self._download_json(
                'http://www.bbc.co.uk/programmes/%s/playlist.json' % playlist_id,
                playlist_id, 'Downloading playlist JSON')
            formats = []
            subtitles = {}

            for version in playlist.get('allAvailableVersions', []):
                smp_config = version['smpConfig']
                title = smp_config['title']
                description = smp_config['summary']
                for item in smp_config['items']:
                    kind = item['kind']
                    if kind not in ('programme', 'radioProgramme'):
                        continue
                    programme_id = item.get('vpid')
                    duration = int_or_none(item.get('duration'))
                    version_formats, version_subtitles = self._download_media_selector(programme_id)
                    types = version['types']
                    for f in version_formats:
                        f['format_note'] = ', '.join(types)
                        if any('AudioDescribed' in x for x in types):
                            f['language_preference'] = -10
                    formats += version_formats
                    for tag, subformats in (version_subtitles or {}).items():
                        subtitles.setdefault(tag, [])
                        subtitles[tag] += subformats

            return programme_id, title, description, duration, formats, subtitles
        except ExtractorError as ee:
            if not (isinstance(ee.cause, compat_HTTPError) and ee.cause.code == 404):
                raise

        # fallback to legacy playlist
        return self._process_legacy_playlist(playlist_id)

    def _process_legacy_playlist_url(self, url, display_id):
        playlist = self._download_legacy_playlist_url(url, display_id)
        return self._extract_from_legacy_playlist(playlist, display_id)

    def _process_legacy_playlist(self, playlist_id):
        return self._process_legacy_playlist_url(
            'http://www.bbc.co.uk/iplayer/playlist/%s' % playlist_id, playlist_id)

    def _download_legacy_playlist_url(self, url, playlist_id=None):
        return self._download_xml(
            url, playlist_id, 'Downloading legacy playlist XML')

    def _extract_from_legacy_playlist(self, playlist, playlist_id):
        no_items = playlist.find('./{%s}noItems' % self._EMP_PLAYLIST_NS)
        if no_items is not None:
            reason = no_items.get('reason')