RTSP: Real Time Streaming Protocol)

RTSP: Real Time Streaming Protocol)
Real-time stream protocol (RTSP) establishes and controls one or more time-synced continuous streaming media, such as audio and video. Although continuous media streams and control flow may cross, RTSP itself does not send continuous streams. In other words, RTSP acts as the network remote control for multimedia servers. RTSP provides an extensible framework for controlled and on-demand transmission of real-time data (such as audio and video. Data sources include live data and stored clips. RTSP is used to control multiple data transmission sessions. It provides a selection of transmission channels (such as UDP, multicast UDP, and TCP), and a method based on RTP.

Currently, there is no RTSP connection concept; the server maintains sessions identified by identifiers. RTSP sessions are not bound to transport layer connections, such as TCP. During an RTSP Session, the RTSP client can enable or disable multiple reliable transmission connections to the server to send an RTSP request. You can also choose to use a connectionless transport protocol, such as UDP.

RTSP-controlled streams may use RTP, but RTSP operations do not depend on the transmission mechanism used to transmit continuous media. RTSP is similar to HTTP/1.1 in syntax and operation. Therefore, the HTTP extension mechanism can be added to RTSP in most cases. However, in many important aspects, RTSP is still different from http:

RTSP introduces a large number of new methods and has a different protocol identifier:
In most cases, the RTSP server must be in the default status, which is opposite to the stateless HTTP server;
In RTSP, both the client and server can send requests;
In most cases, data is transmitted by different protocols;
RTSP uses ISO 10646 (UTF-8) instead of ISO 8859-1, consistent with the current international standard HTML;
URI requests always contain absolute Uris. To be compatible with previous errors, HTTP/1.1 only transmits the absolute path during the request and places the host name in another header field.
The protocol supports the following operations:

Retrieving media from a Media Server: You can submit a demo description request through HTTP or other methods;
The Media Server invites you to a meeting: The Media Server can be invited to an ongoing meeting, play back the media, or record part or all of the presentations;
Add new media to the existing demo. If the server can tell the client the media content available next, it is particularly useful for live broadcasting.
Protocol Structure

RTSP is a text protocol that uses the ISO 10646 character set in UTF-8 encoding. A line can be terminated through CRLF, but the receiving end must be prepared to interpret Cr and LF as a line terminator. The header fields are described 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
User-Agent	R	OPT.	All
Via	G	OPT.	All
WWW-Authenticate	R	OPT.	All

Type "G" indicates the common request header in the request and response; Type "R" indicates the request header; Type "R" indicates the response header; Type "E" indicates the object header field. The field marked with "Req." in the "support" column must be implemented by the recipient in a special way, while the field "opt." is optional. Note that not all "Req." fields are sent in each request of this type. "Req." indicates that only the client (supporting the response header) and server (supporting the request header) must execute this field. The last column lists the methods for generating header fields. "entity" is used to return all methods of an information subject.

RTSP (Real Time Streaming Protocol), real-time stream transmission protocol, is a TCP/IP protocol system

An application layer protocol in ietfrfc submitted by Columbia University, Netscape, and RealNetworks

Standard. This Protocol defines how one-to-multiple applications can effectively transmit multimedia data over an IP network.

RTSP is located on RTP and RTCP in the architecture. It uses TCP or RTP for data transmission. HTTP and

Compared with RTSP, HTTP transmits HTML, while RTP transmits multimedia data. The HTTP request is sent by the client,

The server responds. When RTSP is used, both the client and server can send requests, that is, the RTSP can be

Bidirectional.

RTSP is a multimedia stream protocol used to control sound or images and allows control of multiple streaming demands at the same time.

The network communication protocol used for transmission is not within the defined range, and the server can choose

It uses TCP or UDP to transmit streaming content. Its syntax and operation are similar to HTTP 1.1, but it is not particularly powerful.

Time Synchronization, So network latency can be tolerated. As mentioned above, multiple streaming request controls are allowed at the same time.

In addition to reducing the network usage on the server side and supporting multi-party video conferencing

(Video conference ). Because it is similar to http1.1, the proxy server

The cache function of <proxy> is also applicable to RTSP, and has a redirection function.

To convert the servers that provide services according to the actual load, so as to avoid concentrated loads on the same server.

Server.
This protocol is used for the C/S model. It is a text-based protocol used to create

And negotiate real-time stream sessions.
Real-time stream protocol (RTSP) is an application-level protocol that controls the transmission of real-time data. RTSP provides

Scalable framework, enabling
Real-time data, such as audio and video, can be controlled and on-demand. The data source includes on-site data and

Data stored in editing
. This protocol is used to control multiple data transmission connections.

Provides methods for UDP and TCP
And provide methods for choosing the RTP-based sending mechanism.
Real-time stream protocol (RTSP) is used to establish and control one or several consecutive time syntaxes.

Continuous Media Stream and Control
Stream delivery * is possible. Generally, it does not send continuous streams. In other words, RTSP acts as a multimedia service

Remote Control of Network
. The RTSP connection is not bound to a transport layer connection, such as TCP. During the RTSP connection, the RTSP user can

Enable or disable multiple
The server can transmit * connections to send RTSP requests. In addition, you can use a connectionless transport protocol, such

UDP. RTSP Flow Control
The stream may use RTP, but the RTSP operation does not rely on the transmission mechanism used to carry continuous media. Real-time

Stream protocols in syntax and Operation
Similar to HTTP/1.1, most HTTP extension mechanisms can be added to RTSP. Protocols Supported

As follows:
Retrieve media from the Media Server:
You can submit a demo description through HTTP or other methods. For example, if the demo is multicast, the demo is a package.

Including for continuous media
The multicast address and port. If the demonstration is only sent to the user through a single broadcast, the user shall provide

Destination Address.
Media Server invited to the meeting:
A Media Server can be invited to an ongoing meeting, play back the media, or record part of it,

Or all. This mode
Distributed education application is very useful. In the meeting, you can take turns to press the remote control button.
Add media to off-the-shelf lectures:
It is particularly useful for on-site lectures if the server tells users that they can obtain additional media content. For example

Similar to RTSP in HTTP/1.1
Requests can be processed by agents, channels, and caches.
The RTSP features are as follows:
Scalability:
The new method and parameters can be easily added to RTSP.

Easy to resolve:
RTSP can be parsed by standard HTTP or mime parser.
Security:
RTSP uses the webpage security mechanism.
Independent from transmission:
RTSP can use unreliable Datagram Protocol (UDP) and reliable Datagram Protocol (RDP). To achieve application-level reliability, you can
Use reliable stream protocol.
Multi-server support:
Each stream can be placed on different servers. The user end automatically establishes several concurrent control connections with different servers.
Transport Layer execution.
Record Device Control:
Protocol control records and playback devices.
Separation of traffic control and meeting initiation:
Only the Conference Initialization Protocol is required, or a unique conference id can be created. In special cases, sip or H.323
Can be used to invite servers to the meeting.
Suitable for professional applications:
With SMPTE time scales, RTSP supports frame-level precision and remote digital editing.
MATERIALS:
Http://dslab.ee.ncku.edu.tw /~ Lily/learning/learning_ch2-1.html