@Marc Mroz
I have a plugin that is working. However, Stream is not showing the video. The plugin works as I described in my last comment. It makes a request to the oEmbed endpoint when a proper Stream URL is recognized. The MS Stream oEmbed returns properly formatted JSON and WordPress converts that JSON to properly formatted HTML and embeds that in the post. Here is what is the JSON returned and the HTML embedded in the post
{
"type":"video",
"version":"1.0",
"title":"",
"provider_name":"Microsoft Stream",
"provider_url":"https://stream.microsoft.com",
"embed_url":"https://web.microsoftstream.com/embed/video/3e4b67a0-de91-482f-84ca-78b2196c1810?autoplay=false\u0026showinfo=true",
"html":"\u003ciframe width=\"640\" height=\"360\" src=\"https://web.microsoftstream.com/embed/video/3e4b67a0-de91-482f-84ca-78b2196c1810?autoplay=false\u0026showinfo=true\" style=\"border:none;\" allowfullscreen\u003e\u003c/iframe\u003e",
"width":640,
"height":360,
"thumbnail_url":"https://amsglob0cdnstream13.azureedge.net/streamlogo/Light_640x360.jpg"
}
<div style='max-width: 640px'>
<div style='position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden;'>
<iframe loading="lazy" width="640" height="360" src="https://web.microsoftstream.com/video/3e4b67a0-de91-482f-84ca-78b2196c1810?autoplay=false&showi..." allowfullscreen style="border:none; position: absolute; top: 0; left: 0; right: 0; bottom: 0; height: 100%; max-width: 100%...">
</iframe>
</div>
</div>
Attached is what is displayed on the site in Firefox and Chrome. Basically Stream is refusing the connection. I am authenticated to my corporate MS account and can view the video if I go to Stream.