How to apply dynamic animation?

Question

fmpeg

In general, there is a direct stream and it is necessary to impose animation. For a long time my guys dug and a number of problems arose. Here's what they tried to build:
OBS to hook the stream and overlay animation using the Browser Plugin . That is, the site makes animation, and OBS superimposes it on the video broadcast. The method itself is not bad, except for problems:
a) Only one stream can be processed on one computer, and the computer for [email protected] should be very good. Modern processor and vidyaha.
b) OBS requires a physical video card (it does not use it for decoding, which is strange in itself, all builds through Nvidia chips - they are only for recording at high speeds). All this was tested within the framework of virtualization when working through Ubuntu 14.04 + GNOME.
c) Curve capture RTMP Source. Sometimes it works correctly with 15 frame cache, and even restarts pretty well in case of a crash. Sometimes it doesn't want to restart.
In fact, the ideal solution is ffmpeg + some kind of plugin that captures an image from the site. Is there such a plugin or is there some other solution?