server - RaspberryPi 3 - VLC stream has no audio on 1st try, works on 2nd try

i've installed ubuntu server on rpi3 , trying stream audio , video usb webcam attached it.

but when streaming, seem unable audio working first time run vlc, though works second time , on.

here relevant vlc logs , think may relevant bit of first log:

access_alsa demux warning: cannot read samples: broken pipe

i should point out need run prior opening vlc:

v4l2-ctl --device=/dev/video0 --set-fmt-video=width=640,height=480,pixelformat=1

i in order make sound work on rpi - seems odd don't need such thing on ubuntu desktop. anyway, part explained bit here.

Primitatvve