Thank you!

Correction: "Add", not "at"

It seems so, yes.

The error appears both in .ogv (as exampled above) and .webm files such as this one: https://en.wikipedia.org/wiki/File:Schlossbergbahn.webm

It does seem to be the same issue as in that mentioned ticket. Although it's not about MediaWiki code, the problem remains. To continue, should i post it somewhere else?

Thanks. I would prefer if Mediawiki has support for flowed text, but these solutions work ok in the meantime.

Yes, preferably. If that isn't possible, I'd like <meta> tags in the wikitext to show as <meta> in the source code rather than &lt;meta&gt;

Currently, the main problem is that, instead of <meta>, these tags currently show as &lt;meta&gt; in the source code

What I would like is that the meta tags in the following article would work: https://en.wikiversity.org/wiki/Wikiversity_Journal_of_Medicine/Caesarean_section_photography