VLC media player
Install VLC media player
sudo apt install vlc
Open VLC

Right-click on the interface, go to Open Media -> Open Capture Device

In the Capture Device tab, you can select the capture mode and video device, or toggle the advanced options.

Here are the parameters you can toggle in the advanced options.

Once you click OK to save the advanced options and then Play in the Open Media window, you will be able to see the video feed.

Other Players
mplayer:
mplayer tv://-tv driver=v4l2:width=640:height=480:device=/dev/video0 -fps 30
mencoder tv:// -tv driver=v4l2:width=320:height=240:device=/dev/video0 -nosound -ovc lavc -o myvideo.avi
streamer
streamer -c /dev/video0 -f jpeg -F stereo -o myvideo.avi -t 0:05