# According to [4] data-video-id may be prefixed with ref:
r'''(?sx)
<video[^>]+
- data-video-id=["\']((?:ref:)?\d+)["\'][^>]*>.*?
+ data-video-id=["\'](\d+|ref:[^"\']+)["\'][^>]*>.*?
</video>.*?
<script[^>]+
src=["\'](?:https?:)?//players\.brightcove\.net/