gstreamer and v4l , alsa

1.gstreamer defines a set of data structs, and entry point prototypes for
multimedia pipeline
2.Each component of the pipeline has its set(ds,fptrs)
3.v4l,alsa,oss etc were designed and developed independent of this pipeline
4.gstreamer wrapped the v4l/alsa calls in its interfaces and exposed to the user
5.so earlier what was like app-->v4l-->driver-->hw now became app-->gstreamer-->v4l-->gstreamer-->driver-->hw etc ...