RTSP maintains a state by default which happens to be very important in streaming media files.
The HTTP protocol is a stateless protocol . This simply means that HTTP is unable to retain a memory of the identity of each client that connects to a web site and therefore treats each request for a web page as a unique and independent connection, with no relationship whatsoever to the connections that preceded it.
The RTSP Content Markup Language document can be defined using an XML DTD (Document Type Definition), and is HTML-like. Most of it is self-explanatory. The ’group’ includes two audio tracks and a video track, and the ’group’ tag includes the language parameter (en =English) and a requirement that the sound shall be lip-synchronised with the video. The ’swich’ tag indicates that we can swich between two sound tracks. The coding schemes for the audio are given by the parameters ’e’ and ’pt’. To locate resources, RTSP defines a variant of URL, see ’src’. The parameter ’lofi’ indicates ’low fidelity’ sound. The RTSP URL may include a port number .
RTSP Methods Description Retrieves the description of a presentation Posts the description of a presentation Retrieves the value of a parameter Queries the available methods Streams delivery is halted temporarily Starts sending data Starts receiving data Informs to connect another server location Specifies the transport mechanism Requests to set the value of a parameter Stops the stream delivery and frees the resources Method DESCRIBE ANNOUNCE GET_PARAMETER OPTIONS PAUSE PLAY RECORD REDIRECT SETUP SET_ PARAMETER TEARDOWN