I need to know, how I can create a video banner in SharePoint Online? I tried to create by adding web-part but that is not in a format of banner. Each time I need to play video in order to see it, but I need like as an advertisement banner .
Does the video need sound? if not perhaps you can find a way to convert the video into an animated GIF. Then it will animate and could behave like a banner so users can click on it go somewhere.
Sorry SharePoint's video play back is rather basic so I don't believe you will find much in regards to customizing it.
I don't think there is any Autoplay feature present in SharePoint Online.
Videos from youtube or any other sites having autoplay feature can be embed
You can refer to this article.
You can add the video to a Document library, and follow the steps in the article, add it to the banner by the content search web part.