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?