RTSP works by employing a request-response model for communication between clients and servers. This protocol allows clients to send commands to the server, directing it to perform various actions such as initiating a session, pausing playback, or seeking a specific timestamp. By utilizing this approach, RTSP enables seamless control over streaming sessions. RTSP finds extensive usage in a range of scenarios, including surveillance CCTV cameras, where it facilitates live streaming and remote monitoring.
To establish a streaming session, the client sends an RTSP DESCRIBE request to the server. The server then responds with information about the available media streams, such as codecs, bitrates, and URLs. The client then sends a SETUP request to specify the transport parameters for the desired media stream. Once the session is set up, the client can issue PLAY, PAUSE, and TEARDOWN commands to control the playback.
To make this process a little clearer, here are some of the common procedures of this protocol:
1.The client establishes a TCP connection with the server using the default port for RTSP, which is 554.
2.The client sends an RTSP request to the server, specifying the desired operation (e.g. play, pause, record) and the URL of the media stream.
3.The server responds to the client’s request, indicating the availability and details of the requested stream.
4.If the stream is available and the client has the necessary resources, a media session is established.
5.The server begins streaming the multimedia content to the client over a separate data channel, typically using RTP.
6.The client receives the media data and renders it for playback.
However, this all happens in a matter of moments, so the client doesn’t even realize that all of this is happening behind the scenes.