Play video with v4l2convert using GStreamer

Hello,
I am using gstreamer to play video with audio using below command
gst-launch-1.0 filesrc location=video.mp4 ! decodebin name=dec dec. ! queue ! videoconvert ! videoscale ! video/x-raw,width=480,height=800,pixel-aspect-ratio=1/1 ! autovideosink dec. ! queue ! audioconvert ! audioresample ! autoaudiosink

But I need to use v4l2convert in place of videoconvert and need to scale the video with ratio 1/1 . And the modified command I am using is

gst-launch-1.0 filesrc location=video.mp4 ! decodebin name=dec dec. ! queue ! v4l2convert ! videoscale ! video/x-raw,width=480,height=800,pixel-aspect-ratio=1/1 ! autovideosink dec. ! queue ! audioconvert ! audioresample ! autoaudiosink

But the above command doesnot play video with the specified aspect ratio . It plays with entire screen.