Hi,
You can try VLC player on your phone to be the client first, as a test. Next if you are using a compute platform that can install gstreamer, you can use that to get the frames. You’d need to use gstreamer with the RDP source as the source in your gstreamer pipeline, then I think some decoding needs to be done then you’d have the image you can process. Once that is done you can use opencv on that image if you’d like.