vlc overview

main modules and their uses in vlc
===================================
http://www.videolan.org/doc/vlc-user-guide/en/ch02.html

DirectShow(win)+ Directsound===v4l2(lin) + alsa

gstreamer defines interfaces and contexts for all components of A/V pipe
directshow does the same on windows
v4l and alsa becomes a sub component of gstreamer
vlc uses v4l2/alsa interface directly for A/V
gstreamer plugins are interfaces that wrap around v4l2/alsa apis and make them
consistant with gstreamer specifications
so if vlc was not written in adherence to gstreamer spec, vlc is not a gstreamer app

arch
====
A,B,C,D
v4l2 - C
v4l2 uses D
vlc - B
B uses C
A - gstreamer
B-->C-->D
A-->C-->D
A-->D