_VALID_URL = r'''(?x)https?://
(?:
# Direct video URL
- video\.pbs\.org/video/(?P<id>[0-9]+)/? |
+ video\.pbs\.org/(?:viralplayer|video)/(?P<id>[0-9]+)/? |
# Article with embedded player
(?:www\.)?pbs\.org/(?:[^/]+/){2,5}(?P<presumptive_id>[^/]+)/?(?:$|[?\#]) |
# Player