BV1jK4y1k7Uv
 /BV.*?(\w+)/

https://www.bilibili.com/video/BV1jK4y1k7Uv/?spm_id_from=333.337.search-card.all.click
/^https?:\/\/(?:www|m)\.bilibili\.com\/video\/BV(\w+)/i

https://player.bilibili.com/player.html?bvid=BV1jK4y1k7Uv
/https:\/\/player.bilibili.com\/player.html\?bvid=BV.*?(\w+)/