Hi, I remember, there were a lot of issues with playing video on mobiles in AIR. On some devices were ok, on some not. Investigating issues was painful and almost no response from Adobe.
What about WebGL? Are there issues? Is playing steaming video is unstable and much depends on mobile device? Do you recommend to use it, or to find workaround to get rid of video?
HTML5 video has been relatively reliable in my experience but the cost of running video into a WebGL texture on Chrome (at least) is quite high unfortunately. Using a DOM element can help improve the performance of video a lot
But is it possible to render DOM in perspective view (I think no) and achieve visually as if the video is inside 3D scene? 
How to use DOM element? Can you show please?
Using -Ddom when building would do it, or you would need to write your own code to add an element above the OpenFL stage as OpenFL does not (currently) support a WebGL version + openfl.media.Video over the top using DOM