Raspberry Pi Camera v2 Setup with Mjpg-Streamer [Fluent settings] Needed

Question

I have been working on installing raspberry pi camera v2 with mjpg-streamer to create a local webcam server. When I use my Microsoft HD 3000 Webcam, it is very fluent. But that uses input_uvc.so. Since I want to use input_file.so and that has different configuration parameters, I cant setup a fluent setting. With raspberry pi camera v2, the stream is always like 4-5 frame per second. Why do you think I experience a slow stream in the case of Raspberry Pi Cam v2?

The following is the script I use to initialize the raspberry pi camera v2 and mjpg_streamer

#!/bin/bash
export LD_LIBRARY_PATH=/usr/local/lib
sudo mkdir /tmp/stream/
sudo raspistill --nopreview -w 640 -h 480 -q 5 -o /tmp/stream/pic.jpg -tl 100 -t 9999999 -th 0:0:0 &
/usr/local/bin/mjpg_streamer -i "input_file.so -f /tmp/stream/ -n pic.jpg" -o "output_http.so -w /usr/local/www -p 8081"

Thanks in advance for the help.