As a bit of background we never implemented video placeholders for chat, it just relies on HTML5 video tag features to make it work. We implemented our own placeholder logic originally for topic/posts because videos were auto “downloading” data on every single topic load even if they weren’t being played chewing up cdn costs on popular sites.
I don’t think we need to re-implement the same placeholder logic we have for topics in chat just yet, but there still may be some ios/safari tweaks we will need to make in order for things to work on iOS. I thought just having the preload="metadata" attribute would do the trick, but looks like that is already present.
<video class="chat-video-upload" preload="metadata" height="150" controls="">
<source src="https://actual-url.MOV">
</video>