Thank you - I was able to make it work for one camera with the following changes.
etc/modalai/voxl-camera-server.conf
changed "camera_id_second": to -1 to get just one camera,
changed "en_preview": to false,
Added:"en_small_video": true,
"small_video_width": 1280,
"small_video_height": 800,
restart voxl-camera-server service
etc/modalai/voxl-streamer.conf
"input-pipe": "stereo_small_encoded"
etc/modalai/voxl-mavcam-manager.conf
"video_record_pipe_name": "stereo_small_encoded",