Can not use gst-launch in android terminal with a camera?

I got a question when I use the app Termux which can download a lot linux-like tools,for example I use gstreamer. In termux, I can pkg install gst*, after exec this cmd, I can install gstreamer sucessfully and Use gst-launch-1.0 videosrc, In fact, I want to get video0 frame show on termux terminal.