RTSP - Real Time Streaming Protocol

RTSP was first developed and introduced by Netscape, Columbia University and Real Network in 1998. RTSP allows users to play back remote media content without having to download the media file, greatly improve the over-the-wired video playing experiences. Many other protocols were introduced for internet media playback after RTSP.

Nowaday, RTSP is mainly used in the IP camera world. RTSP protocol allows IP camera users to send PTZ (Pan-Till -Zoom) controls signals to a RTSP Server running inside their IP cameras as well as playing videos/audios files storing inside the IP Camera SD Memory Card.

When received the control signals from users mobile or desktop applications, the RTSP server inside the IP camera will then either start a streaming session and send small trunk of media file to user devices or send control signals to the electric motors to adjust the IP camera to diffrent angles or zoom levels.

A standard IP Cam RTSP Server configuration would be:

• Video: H.264 Video Encoder/Decoder, 15 frames per second.
• Audio Codecs: AAC, 8000 Hz, 64 kb/s.
• Latency: 1-2 secs.

WebRTC - Web Real Time Communication Protocol

WebRTC has extreme low latency for one to small number viewers. It works great for video conferencing or streaming to a small amount of audience like in a small classroom or closed friends context in closed proximity geographic area.

HLS - HTTP Live Streaming Protocol

HLS and HLS Low Latency is for mass distribution with many remote viewers supposed to hoop in to views the live stream. The number of viewers could be in 1000s and viewers are distributed across large geography area.

References

• Wowza on RTSP - Wowza Live Streaming Servers
• Safr Scan - a Product of Real Network - Access control via Real Time Facial Recognition