How to use "encodebin" in a command line to encode raw frames coming from webcam?

[Anirudh]

I am trying to use encodebin in following fashion:

gst-launch  videotestsrc  encodebin name=ebin  ! video/x-h264 ! fakesink
But it is giving error as :
ERROR: Pipeline doesn't want to pause.

I have also tried following command line :
gst-launch  videotestsrc  ! encodebin name=ebin  ! video/x-h264 ! fakesink
This gives foloowing error:
WARNING: erroneous pipeline: could not link videotestsrc0 to ebin

I was able to programmability build the pipeline having encodebin and its working.

I could not find any example using encodebin in command line.

Plz suggest how to use encodebin using gst-launch.