(@emanueleferrara I moved your question to a separate topic, because it has nothing to do with that other one.)
The Video XBlock depends on version 1.3.1 of the XBlock package, while edx-platform requires version 1.4.0 in the Lilac release (see source code).
In other words: the Video XBlock is not compatible with the Lilac release. The last release that depended on version 1.3.1 of the XBlock package is Juniper. So the Video XBlock is late by at least two releases.
I suggest that you get in touch with the maintainers of the video xblock directly.