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

Code before:
        video_info = self._get_video_info(ep_number, program_slug, display_id)
        try:
            source_json = self._download_json(
                f'https://odkmedia.io/odc/api/v2/playback/{video_info["id"]}/', display_id,
                headers={'Authorization': '', 'service-name': 'odc'})
        except ExtractorError as e:
            error_data = self._parse_json(e.cause.read(), display_id)
            raise GeoRestrictedError(error_data.get('detail'))

        formats, subtitles = [], {}
        for source in traverse_obj(source_json, ('sources', ...)):
            if source.get('type') == 'hls':
                fmts, subs = self._extract_m3u8_formats_and_subtitles(source.get('url'), display_id)
                formats.extend(fmts)
                self._merge_subtitles(subs, target=subtitles)

        return {
            'id': str(video_info['id']),
            'duration': float_or_none(video_info.get('videoDuration'), 1000),
            'thumbnail': (traverse_obj(video_info, ('images', 'thumbnail'))
                          or self._html_search_meta(['og:image', 'twitter:image'], webpage)),
            'title': (video_info.get('title')
                      or self._html_search_meta(['og:title', 'twitter:title'], webpage)
                      or self._html_extract_title(webpage)),
            'alt_title': (video_info.get('titleKo') or video_info.get('titleZhHans')
                          or video_info.get('titleZhHant')),
            'description': (video_info.get('synopsis') or video_info.get('synopsisEn')
                            or video_info.get('synopsisKo') or video_info.get('synopsisZhHant')
                            or self._html_search_meta(
                                ['og:description', 'twitter:description', 'description'], webpage)),
            'formats': formats,
            'subtitles': subtitles,
            'tags': try_call(lambda: self._html_search_meta('keywords', webpage).split(", "))
        }


Review comment (suggestion):
```suggestion
            'alt_title': traverse_obj(video_info, 'titleKo', 'titleZhHans', 'titleZhHant'),
```

Code after:
import json
import urllib.error

from .common import InfoExtractor
from ..utils import (
    ExtractorError,
    GeoRestrictedError,
    float_or_none,
    traverse_obj,
    try_call
)


class OnDemandChinaEpisodeIE(InfoExtractor):
    _VALID_URL = r'https?://www\.ondemandchina\.com/\w+/watch/(?P<series>[\w-]+)/(?P<id>ep-(?P<ep>\d+))'
    _TESTS = [{
        'url': 'https://www.ondemandchina.com/en/watch/together-against-covid-19/ep-1',
        'info_dict': {
            'id': '264394',
            'ext': 'mp4',
            'duration': 3256.88,
            'title': 'EP 1 The Calling',
            'alt_title': '第1集 令出如山',
            'thumbnail': 'https://d2y2efdi5wgkcl.cloudfront.net/fit-in/256x256/media-io/2020/9/11/image.d9816e81.jpg',
            'description': '疫情严峻，党政军民学、东西南北中协同应考',
            'tags': ['Social Humanities', 'Documentary', 'Medical', 'Social'],
        }
    }]

    _QUERY = '''
        query Episode($programSlug: String!, $episodeNumber: Int!) {
            episode(
                programSlug: $programSlug
                episodeNumber: $episodeNumber
                kind: "series"
                part: null
            ) {
                id
                title
                titleEn
                titleKo
                titleZhHans
                titleZhHant
                synopsis
                synopsisEn
                synopsisKo
                synopsisZhHans
                synopsisZhHant
                videoDuration
                images {
                    thumbnail
                }
            }
        }'''

    def _real_extract(self, url):
        program_slug, display_id, ep_number = self._match_valid_url(url).group('series', 'id', 'ep')
        webpage = self._download_webpage(url, display_id)

        video_info = self._download_json(
            'https://odc-graphql.odkmedia.io/graphql', display_id,
            headers={'Content-type': 'application/json'},
            data=json.dumps({
                'operationName': 'Episode',
                'query': self._QUERY,
                'variables': {
                    'programSlug': program_slug,
                    'episodeNumber': int(ep_number),
                },
            }).encode())['data']['episode']

        try:
            source_json = self._download_json(
                f'https://odkmedia.io/odc/api/v2/playback/{video_info["id"]}/', display_id,
                headers={'Authorization': '', 'service-name': 'odc'})
        except ExtractorError as e:
            if isinstance(e.cause, urllib.error.HTTPError):
                error_data = self._parse_json(e.cause.read(), display_id)['detail']
                raise GeoRestrictedError(error_data)

        formats, subtitles = [], {}
        for source in traverse_obj(source_json, ('sources', ...)):
            if source.get('type') == 'hls':
                fmts, subs = self._extract_m3u8_formats_and_subtitles(source.get('url'), display_id)
                formats.extend(fmts)
                self._merge_subtitles(subs, target=subtitles)
            else:
                self.report_warning(f'Unsupported format {source.get("type")}', display_id)

        return {
            'id': str(video_info['id']),
            'duration': float_or_none(video_info.get('videoDuration'), 1000),
            'thumbnail': (traverse_obj(video_info, ('images', 'thumbnail'))
                          or self._html_search_meta(['og:image', 'twitter:image'], webpage)),
            'title': (traverse_obj(video_info, 'title', 'titleEn')
                      or self._html_search_meta(['og:title', 'twitter:title'], webpage)
                      or self._html_extract_title(webpage)),
            'alt_title': traverse_obj(video_info, 'titleKo', 'titleZhHans', 'titleZhHant'),
            'description': (traverse_obj(
                video_info, 'synopsisEn', 'synopsisKo', 'synopsisZhHans', 'synopsisZhHant', 'synopisis')
                or self._html_search_meta(['og:description', 'twitter:description', 'description'], webpage)),
            'formats': formats,
            'subtitles': subtitles,
            'tags': try_call(lambda: self._html_search_meta('keywords', webpage).split(', '))
        }