difference between RTSP & HTTP protocols

Question

hi
i want to connect to a ip camera for image processing. i want to know what's difference between RTSP and HTTP protocols in getting image or video from camera. i need to an online image processing. i mean i need to get pictures or video real time and process them real time.

now if i use RTSP (Real Time Streaming Protocol) is better or HTTP?

please tell me your suggestion.

thanks a lot.