Video Addon not working properly

I think I understand the problem. Maybe someplace in the documentation it shares this information. Here's what I learned:
Each browser handles video differently.
IE will let you autoplay a video with sound automatically upon loading the website. (without controls)
Other browsers are not so friendly. They let you auto play the video, but only with audio muted. Or you can show controls then you have different options. Not so friendly IMHO.

I continue this thread because I have the same issue but not the same solution (yet). In backend my mp4 plays fine but not on the live site. I guess it is because of its <source> tag which has a src="/xyz" attribute in backend but not in frontend. Here it says data-large="xyz".

With "frontend" it's meant the live site. Not frontend editing. This works as mentioned.

DOM while editing

DOM on live site

Thanks for your answer,

1. I'm using a template custom build by my own.
2. It is the video addon. Is there another way to insert videos?

And actually I mean "data-large" attribute from this mp4 video, not ogg. So while editing it is src:

<video class="sppb-addon-video-local-source" autoplay="" controls="" muted="" poster="http://motteduesseldorf.de/images/logos/logo_72_tr.webp" controlslist="nodownload">
    <source src="http://www.motteduesseldorf.de/media/videos/2021/08/16/whatsapp-video-2021-07-02-at-17.29.57.mp4" type="video/mp4">
</video>

On live site it has changed to data-large:

<video class="sppb-addon-video-local-source" autoplay="" controls="" muted="" data-poster="/images/logos/logo_72_tr.webp" controlslist="nodownload" playsinline="">
    <source data-large="http://www.motteduesseldorf.de/media/videos/2021/08/16/whatsapp-video-2021-07-02-at-17.29.57.mp4" type="video/mp4">
</video>

And when I insert a HTML addon with following code (with src) it will work, too (while editing and on live site:

<video data-poster="/images/logos/logo_72_tr.webp" autoplay muted>
    <source src="http://www.motteduesseldorf.de/media/videos/2021/08/16/whatsapp-video-2021-07-02-at-17.29.57.mp4" type="video/mp4">
</video>

Hope this will help.

I had to replace “data-large“ with “src“ so it worked. But why is this addon's code written like that so it won't work until replacing code by the user?