[Freeswitch-users] rtmp is sending as 160x120 inset within 320x240 instead of fullscreen

When we configure getUserMedia to send 320x240 (using recent Chrome), and then in our FS 1.10.5 dialplan we forward that as rtmp this way... <action application="record_session" data="{modname=mod_av,vw=320,vh=240}rtmp://mydomain.com"/> ...an ffmpeg capture reveals the user video to be only a 160x120 inset (against the left margin and centered vertically). The rest of the frame is black. I've looked in av.conf.xml, vars.xml, and conference.conf.xml for any setting that might explain this; it seems like a 2-person conference layout (and we are using a conference with a virtual agent with setting 'mintwo' and <param name="max-members" value="2"/> How can we fill the rtmp frames with 320x240 of only the verto user?