Easy way to watch the demo of libvisual plugin.

When I checked the source code of libvisual on debian sid,I feel like to watching the demo of libvisual plugin.
I'm looking around for the easiest way of this, I seems to find out. I memorize here.

Notice: I'm currently using alsa interface. I don't know how-to in other audio interface(ex. palseaudio,esound,jack,etc...)

1) Enable alsa mixier as capture device,according to this wiki: Alsa Opensrc Org - Independent ALSA and linux audio support site.
2) Play some music via alsa.(ex. aplayer,totem,rhythmbox,etc...)
3) Invoke visualizer like this,

gst-launch alsasrc ! audioconvert ! queue ! libvisual_lv_analyzer ! ffmpegcolorspace ! xvimagesink

(This command show the demo of lv_analyzer visual plugin. If you want to demonstrate another plugins in this form 'libvisual_'.)

Then, the visualization of currently playing music begins like this,