I'm trying to superimpose a video over another video by using the mfw_isink element in gstreamer. I can't find out how to specify which video should be present on top and which video should be present below. Even the documentation provided in Linux_Multimedia_Framework_Docs_MX6X does not specify how to do that. One thing i noticed is that whichever VS is created last is present on top. For example if 2 overlays VS0 (0,0-800,800:800x800) and VS1 (200,200-1000,1000:800x800) are created in the same order, The video present in VS1 superimposes on top of the video present in VS0. The pipelines I'm using are
gst-launch videotestsrc ! mfw_isink display=master axis-left=0 axis-top=0 disp-width=800 disp-height=800 videotestsrc ! mfw_isink display=master axis-left=200 axis-top=200 disp-width=800 disp-height=800 rotation=1
gst-launch videotestsrc ! mfw_isink display=master axis-left=0 axis-top=0 disp-width=800 disp-height=800 videotestsrc ! mfw_isink display=null display-1=master axis-left-1=200 axis-top-1=200 disp-width-1=800 disp-height-1=800 rotation-1=1
By repeatedly running either of the above pipelines, sometimes i get the rotated video to be present on top. This is because, for that instance VS0 contains video in window (200,200-1000,1000:800x800) and VS1 contains video in (0,0-800,800:800x800). I don't know why this happens but this happens randomly. I want know how to make the rotated video appear on top of the other video. Or is there anyway to specify which overlay should be created first (or present in top/bottom)? Any comments or suggestions are welcome. Thank you.