Hi,
I don't know what AVB is, but MX6 works fine (with mainline Linux + a lot of patches currently heading towards mainline) with cameras and streaming. Note that for video applications we usually work with buffers, which are a bit against a "realtime" concept. But you can for example stream videos via RTP and display it with any media player on the other side. We do that in automotive applications by using the currently developed mainline IPU+VPU drivers, a gstreamer filter plugin that works on v4l2 mem2mem devices and the usual gstreamer chain (0.11+ with dynamic pipelines) on top of that.
So it's all possible, but needs a lot of "work-in-progress" technologies.
Regards,
Robert