Plattar currently supports mp4 (H264) videos. You must make sure your video is suitable for streaming before uploading it, as Plattar will not compress or otherwise alter your video.
Our recommended settings are either 720p (if the user will get close to the video, or for greenscreen) or 640x320 (ok for videos in scenes with other objects) at 2Mbps/2000Kbps.
The file size will depend on how long the video is, but remember that watching very long videos as part of an AR scene can be uncomfortable. Consider using a youtube link for larger videos.
When using greenscreen videos, to get the best ‘key’ (the cleanest removal of the background) its best to do most of the heavy lifting ahead of time in a video editor.
You can crop out small items like cables, microphones etc, and dial in a really clean key using many desktop video apps. Once complete, composite the video back onto pure green (RGB: 0,255,0). This will give you great results in the 3D editor.