Real-time flow protocol RTSP establishes and controls a continuous stream of continuous streams synchronized by one or time. Although continuous media streams and control flow intersect, usually it does not send continuous streams, such as audio and video. In other words, RTSP acts as a network remote control of a multimedia server. RTSP provides an extensible framework that controls real-time data such as audio and video, as needed to transmit. The data source includes field data and data stored in the clip. The protocol is an object of controlling multiple data transmission sessions, providing a way for selecting a transmission channel such as UDP, multicast UDP and TCP, and provides a method for selecting RTP-based transmitting mechanisms.
There is currently no specific RTSP connection concept, which is replaced by a session that is maintained by the server. The RTSP session is not bound to the transport layer connection, such as TCP. During the RTSP session, the RTSP user can turn off or off multiple reliable transfer connections to the server to issue RTSP requests. In addition, you can use no connection transport protocol, such as UDP.
The RTSP stream control flows may be used to RTP, but the RTSP operation does not depend on the transmission mechanism for carrying continuous media. The real-time flow protocol is similar to HTTP / 1.1 in syntax and operation, so the HTTP expansion mechanism can be added to RTSP. Despite this, RTSP is still different from http in many important aspects:
RTSP introduces a large number of new methods and has a different protocol identifier: In most cases, the RTSP server needs to maintain the default state, the state of state is relatively; the media users and servers can issue a request in the RTSP; in most cases Data from different protocols; RTSP is defined to use ISO 10646 (UTF-8) rather than ISO 8859-1, consistent with the current international standard HTML; URI request has always included a complete URI. Because of the mutual compatibility with historical errors, HTTP / 1.1 transmit a full path only during the request process and place the host name in a single header field.
The protocol supports the following:
Retrieve media from the media server: Users can submit a presentation description via HTTP or other methods; media server invitations Enter conference: Media servers can be invited to participate in the positive meeting, or play back the media, or record some of them, or all; Add to the ready-made lecture: If the server tells users to obtain additional media content, it is especially useful for on-site lectures.
Protocol structure
RTSP is a text protocol, UTF-8 encoding is set with ISO 10646 characters. Terminate the line through the CRLF, but the receiving end needs to be prepared for conversion CR and LF. About the header field is as follows:
Header Type Support Methods Accept R opt. Entity Accept-Encoding R opt. Entity Accept-Language R opt. All Allow R opt. All Authorization R opt. All Bandwidth R opt. All Blocksize R opt. All but OPTIONS, TEARDOWN Cache-Control G opt. SETUP Conference R opt. SETUP Connection G req. all Content-Base E opt. entity Content-Encoding E req. SET_PARAMETER Content-Encoding E req. DESCRIBE, ANNOUNCE Content-Language E req. DESCRIBE, ANNOUNCE Content-Length E req. SET_PARAMETER, ANNOUNCE Content-Length E req. entity Content-Location E opt. entity Content-Type E req. SET_PARAMETER, ANNOUNCE Content-Type R req. entity CSeq G req. all Date G opt. all Expires E opt. DESCRIBE , ANNOUNCE From R opt. all If-Modified-Since R opt. DESCRIBE, SETUP Last-Modified E opt. entity Proxy-Authenticate Proxy-Require R req. all Public R opt. all Range R opt. PLAY, PAUSE, RECORD Range R Opt. Play, Pause, Record Referer R Opt. All Require R REQ. All Retry -After R Opt. All RTP-INFO R Req. Play Scale Rr Opt. Play, Record session rr Req. All but setup, Options Server R Opt. All Speed RR Opt. Play Transport RR Req. Setup Unsupported R REQ. All.er-agent R Opt. All-version R Opt. Alltype " g "represents the general request head in the request and response; TYPE" R "represents the request head; Type" R "indicates the response head; Type" E "means the entity header field. Note "Req." Of the "Support" tag must be implemented by a special method; and "OPT." Has multiple options. Note that not all "REQ." Fields are sent in each request of this type. "REQ." only means that the client (supported head) and server (support request head) must perform this field. The last column lists the method of generating the first field; "Entity" is for all methods of returning a message entity.
Related protocols UDP, TCP, HTTP, S-HTTP, RTP Organizational Source RTSP is defined in RFC 2326 by IETF (www.ietf.org). Related Link http://www.javvin.com/protocol/rfc2326.pdf: Real Time Streaming Protocol
