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RFC2326 Real Time Streaming Media Protocol (RTSP) This memo: This document describes an Internet standard path protocol in the Internet Transfer Protocol, and in order to improve the need to discuss and recommend. Please check the correct, the standardized statement of the standardized statement and the situation of the standardization and the situation of the INTF. Distribute this memo is not limited.
Summary: Real Time streaming media protocol or RTSP is a tool for controlling real-time transfer data on an application layer. RTSP provides an extensible framework that provides real-time data, such as audio, and video files that can be controlled. The source data can include feedback and storage of field data. This protocol consciously controls multiple data, delivers a meeting, providing a selection delivery channel, such as UDP, multi-point delivery UDP, and TCP, and a RTP (RFC1889) selection transfer mechanism. Directory content: (omitted).
1. Introduction 1.1 Purpose Real Time Flow Media Transport Protocols Establish and control a simple, or several time synchronization, continuous media streams, such as audio and video. He is not a representative transfer of continuous streams, despite the consolidated contiguous media Flow is possible (see chapter 10.12). Another point, RTSP serves as a network remote control for multimedia services.
The setting of the controlled stream is defined by a description. This memo is not a format for the image definition.
There is no concept of RTSP connection here: replacing, a server maintenance, a meeting of a verifiable tag. An RTSP meeting is never connected to the transport layer, such as TCP connections. In an RTSP meeting, an RTSP conference client can open a number of reliable transmitters, connect to the server sent to the RTSP request, as a selection, which can use no connection transport protocol, such as UDP.
RTSP control flow can use RTP, but the operation of RTSP does not rely on the transmission mechanism of the usual transmission of continuous media. This protocol is intentionally operated on HTTP / 1.1. Therefore, the HTTP extension mechanism can be added to RTSP to the greatest extent. However, many important differences between RTSP and HTTP are: * RTSP introduces many new modes and has a different protocol identifier. * An RTSP server needs to maintain almost all situations by default to maintain normal operation. * The RTSP server and the client can issue a request. * Data is transmitted through different protocols. * RTSP is defined by ISO 10646 than ISO 8859-1 so that it is consistent with the current HTML international effort. * Requires URI to always include absolute URI. Because of the backward compatibility in history, HTTP / 1.1 can only pass the required absolute path, put the host name into the title bar that does not contact. This makes the "virtual host" easier, then, a single host with 1 IP address can serve several file trees.
This Agreement supports operation: Removing Media Data from Media Server: The client can require an image to describe by HTTP or other mode. If the image is transferred by a multi-point, the image description contains the address and port of multi-point transmission to transmit consecutive media. If the image can only pass through Unicast, the client will provide the destination file due to safety.
Invitation to the media server for the meeting: A media server side can be invited to participate in an existing meeting, play an image backward, record all or part of the media file. This mode is useful for distributed teaching software. See Several sections in the meeting can press the Remote Control button.
Add a media to the present image: especially the existing image, if the server can tell the client to use the supplementary media, it is useful.
The RTSP requirements in HTTP / 1.1 [2] can be through proxy, channels, and caches. 1.2 Requires "necessary" in these documents, "must not", "necessary", "will", "no", "should", "should not", "recommended", "can" And "selectable" is explained in RFC 2119.
1.3 Terminology Some terms are used in http / 1.1. It is not listed here. Overall control: Multi-stream control uses a simple timeline through the server. For the feedback of audio / video, a simple start or pause instruction can be sent to control video / audio feedback through the client. Discussion: An image of a multi-component, multimedia, more representation is greater than or equal to one. Client: The client requests continuous media data from the server side. Connection: The transport layer virtual line determined between the two programs for the purpose of communication. Container file: You can include multimedia, when the file containing the image is opened. The RTSP server can provide overall control over these files, although the concept of container files is not in the implant protocol. Continuous media: Data is a real-time relationship between data sources and connections, that is, the receptacle and data source should constantly generate a relationship join. Examples of the most common continuous media are audio and animated video. Connecting media can work interactively, and they are a close real-time relationship between the source and receivers. Or the form of flow, this relationship is not so strict. Entity: It is a valid load of a request or response. An entity is included in the form of the head and content in the entity. These are introduced in the eighth. The initialization of the media: Multimedia digital codec is special initialization, including clock rate, color table, etc. Any request for independent transmitter information is achieved through the media stream in the media initialization setting phase. Media parameters: A specific parameter of a media type can change when flown forward or playback. Media Server: Server If you play back one or more media streams, images within different media streams can come from different media servers. A media server can be placed on the same or different hosts. Media Server Randid: Reallo a media client to different media servers. Flow: A simple media instance, such as an audio stream or a simple white class or shared application group. When using RTP, a stream consists of RTP and RTCP created in the RTP cycle, this is and DSM-CC The flow definition is the same. Message: Basic Unit of RTSP Communication. The structured sequence of the eight-bit matching syntax defined in 15 chapters and is transferred through a connection or no connection protocol. Participants: a meeting member. A participant can be a machine, such as a media record or playback server. Statement: A set of complete media feedback from one or several streams, and delivers the following expression statements to the client. In most cases in the RTSP context, this means that the body control of these streams, but not necessarily. Statement Description: A statement describes information about one or more media streams inside a statement. For example, a set of connection coding, network addresses, information. In addition, like the TETF protocol of SDP, using on-site statement as a meeting. This statement can be used in different formats, which is not limited to the conference description of SDP arrangements. Response: An RTSP response. If an HTTP response can be accepted, it can be clearly expressed. Request; an RTSP request. If an HTTP request can be accepted, it can be clearly expressed. RTSP Conference: A complete RTSO process. For example, a movie viewing process. A meeting usually establishes a transport mechanism for continuous media streams, starting a stream with playback or video, shutting down the stream with stop. Transmitter Initialization: The negotiation of the transmitter information (port number, transport protocol, etc.) between the client and the server.
1.4 Protocol Properties RTSP has the following properties: scalability: new mode and parameters can be easily added to RTSP. Easy to resolve: RTSP can be parsed by standard HTTP or MIME. Safety: RTSP also uses the network security mechanism. All HTTP verification mechanisms such as basic (RFC 2068 [2, 11) and classifications can be used directly, or they can reuse the transmitter or network layer security mechanism. Transmission independence: RTSP can use the user datagram protocol (RFC 768), a reliable transmission protocol (RDP, RFC 1151, not widely used) or a reliable flow protocol, such as TCP, as a reliable execution application layer. Multi-server capability: Each media stream can come from different servers when playback, and the client is automatically created several concurrent control conferences, and the media synchronization is performed on the transport layer. The control of the recording device: This protocol can simultaneously control video and play, or select one of the modes. Separation and meeting of stream control: flow control is from separated from a conference media server. The only requirement is that the conference start agreement can be provided and a new conference identifier can be created. In special cases, STP or H.233 can establish a server for a meeting. Suitable for professionals: RTSP supports the accuracy of the frame layer. Tagging through the SMPTE time, allowing subtle data editing. The neutrality of the type of play: This Agreement does not enhance a special playback description or graph format, and the type capable of passing the delivery. However, the playback must contain at least one RTSP connection. Friendly of proxy and firewall: This Agreement should be easily mastered by applying layer and transport layer firewall. A firewall is desirable to understand the "holes" established model for UDP media. HTTP Friendly: After clarifying RTSP re-use HTTP concept. In this way, the current infrastructure can be used again. This infrastructure contains PICS for tags and content grounds. However, the control continuous media requires the server state after most examples, RTSP cannot be added to HTTP. Assign Server Control: If the client starts a stream, it must stop the stream. The server should not start flow to the client so that the client cannot stop the flow. Transfer negotiation: The client can actually negotiate the transmission method before you need to apply for a continuous media stream. Ability Negotiation: If the basic feature cannot be used, the client must have some cleaning mechanism to determine which method is not implemented. This allows the client to display the appropriate user interface. For example, if you are not allowed, the user interface must be able to reject the position indicator of the mobile slide. Early requirements in RTSP are multi-client capabilities. However, it is determined to have a better way to make this agreement easily expand multi-client. The stream indicator can be used by several control flow, so that "remote pass" will become possible. This Agreement will not talk about several clients negotiated approach. This is entrusted to the Social Agreement and some other layer control mechanisms.
1.5 RTSP Extension All Media Servers have no different functionality, the media server will have a different set of requirements for requirements. For example: * This server may only be a playback capability without having to support record requirements. * If it only supports events, the server can also find the capabilities (absolute positioning). * Some servers do not support play stream parameters and not get_Parameter and Set_Parameter. The server should implement all the functions described in Section 12. Do not ask if the server is not possible to play the highest level of the creation described. This is similar to that in http / 1.1 [2], at this time, the method 里 in [h19.6] is not possible to be supported by all servers. RTSP can be extended in 3 methods, and is composed herein in order of the size of the supported changes. * To be expanded by the new parameters, as long as these parameters can be ignored by the container. (This and add new parameters to the HTML check bar.) If the mode extension is not supported, the client needs to negate the capabilities. An additional label to the extension is also added to the request: failure (see Chapter 12.32). * The new method can be added. If the acceptance of the information is not understood, it responds with the error code 501 (implementation), and the sender should not try to use this method again. In addition, the client can use any selection method to query the method supported by the server. The server should make it supported by the method you support as a public answer title. * The new version of the agreement allows almost all aspects (except for the location of the protocol version number), and can be defined.
1.6 Overall operation Each statement is recognized near the RTSP URL. All statements and composition media descriptions are defined by statement of the description file, the format is the scope of the book. The playback description file is obtained by using HTTP or like Email through the client, and it is not necessary to place it on the media server. For this purpose, some people assume that the statement describes more than one - each contains the same time axis. Since the description is simple, and the universality is lost, a statement describes how to include this statement. The statement can include several media streams. The statement describes the definition description of the media stream that makes up statements, including their coding, language, and other parameters that enable the client to select the most appropriate combination of the media. In this description, each individual via the RTSP-controlled media stream is recognized by the RTSP URL, where a special media stream is pointed to the media server and a stream named existence server. Several media streams are placed in different servers; for example, sound and video streams are cut in order to pass the server. The description also enumerate that the server can do those transmission methods. In addition to the media parameters, the network destination address and port also need to be determined. Several operations can also be identified: UNICAST: The port number of the media is transmitted to the source of the RTSP. Alternatively, the media is transmitted on the same reliable stream as RTSP. Multi-click, server selection address: Media server picks the address and port. This is a typical situation of the transmission of live or VOD. Multi-point selection, client selection address: If the server is involved in the existing multi-point transfer conference, multi-point transmit ports, addresses, and cryptocatical key conferences are described in this description. 1.7 RTSP specifies that the RTSP can via a separate protocol, a separate control channel controls the sent flow. For example, RTSP is controlled in a TCP connection when data is flowing via UDP. In this way, the data is that the media does not receive the RTSP request, and it can continue to pass. In addition, in its cycle, a single medium stream can be RTSP continuously issued on a different TCP connection. Therefore, the server needs to maintain the conference form to combine the RTSP as required. This form is described in section A. However, the following is the role of the allocation and use of the stream resource on the server: establish, play, recording, pause, and shut down. Establishment: Enable the server to assign resources to the current, start the RTSP meeting. Play and recording; allocated streams have been established started. Pause: temporarily suspend stream on the server. Turn off: Get freedom with resources associated with streams. The RTSP meeting stops on the server. The RTSP mode is attributed to the use of the conference ID (Section 12.37) to identify the RTSP meeting in operation. The server acts as a reactive meeting identifier (Section 10.4) for the preparation requirements.
1.8 Contact RTSP with other protocols In the function, there are some repetitions in HTTP. It can also be connected to HTTP with the original connection of the stream, and it works through the web page. The current protocol description is to allow different pass points between the network server and the media server that implements RTSP. For example, statements have been expressed with HTTP or RTSP, which reduces web browser-based workloads, which also allows stand-alone RTSP server and clients that do not depend on HTTP. However, RTSP is different from HTTP in different protocols. HTTP is an asymmetric agreement requesting the client, and the server acts on. In RTSP, media clients and media servers can come out to respond. In addition, the RTSP requires no boundaries: After accepting it, they can set the parameters and continue to control the media stream for a long time. Repeat the HTTP functionality to use at least two places, security and proxy. It is very similar to the necessary conditions, so they have valuable capabilities in buffering, proxy and prove to adapt to HTTP work. When most of the real-time media uses RTP like the Transport Protocol, RTSP is not bundled on the RTP. RTSP envisaged that the presence format of expression can be static or dynamic, including several server flow properties. 2 International Agreement Since definitions and grammar are similar to HTTP / 1.1, this indicates that they are only part of them being defined rather than copying. For the sake of brevity, [HX.Y] is mentioned in the X.Y section of the RFC [2] 2068). All designated mechanisms in this document can be described in the prose and the method of expanding the backupus-NaUR mode similar to [h2.1]. This will be described in detail in RFC 2234 [17], which is different from the "1 #" distinguishing flag of the RTSP manual. In this record, we provide backgrounds and motives with alternating and small paragraphs. This is intended to give readers who do not express a formula that understand why they are in RTSP.
(See 16) session-id = 1 * (alpha | DIGIT | SAFE) 3.5 SMPTE Relative Time Label A SMPTE relative time tag expresses the time starting with respect to the clip. The relative time label is expressed as a time code for the frequency accuracy of the SMPTE frame. The format of the time code is: Time: Score: Second; frame. Divorition, origin starting at the clip. The default SMPTE format is "SMPTE 30" format, and the frame speed is 29.97 frames per second. Other SMPTE code may be supported (eg, "SMPTE 25") by using the optional "SMPTE Time". The "frame" domain at the time value can be defined between 0 and 29. Different per minute of each minute of 30 and 29.97 frames, except for every tenth minute. If the frame value is 0, it may be ignored, and the subframe is one hundred and thousandth of one frame. SMPTE-RANGE = SMPTE-TYPE "=" SMPTE-TIME "-" [SMPTE-TIME] SMPTE-TYPE = "SMPTE" | "SMPTE-30-DROP" | "SMPTE-25"; Other Timecodes May Be Added SMPTE- Time = 1 * 2Digit ":" 1 * 2Digit ":" 1 * 2Digit [":" 1 * 2Digit] ["." 1 * 2Digit]
For example: SMPTE = 10: 12: 33: 20- SMPTE = 10: 07: 33- SMPTE = 10: 07: 00-10: 07: 33: 05.01 SMPTE-25 = 10: 07: 00-10: 07: 33 : 05.013.6 Normal Playing Time Play Time The normal (NPT) indicates a position where the absolute and performance of the stream has a relationship. The left side of the number can be seconds or hours, minutes, seconds. The right side of the number can be measured one second. The start of the program should correspond to 0.0 seconds. The negative value cannot be defined. The special number is now defined as the current moment of the event. It may only be used for events. NPT is defined in the DSM-CC: Intuitively, NPT is a clock that is connected to the audience and programs. It is often digitized on the VCR. When NPT is approaching, when the quick forward mode (simulation 1) is running forward quickly, the time consumption is consumed in the reverse direction and when the stop is stopped. NPT-RANGE = (NPT-TIME "-" [NPT-TIME]) | ("-" NPT-TIME) NPT-TIME = "NOW" | NPT-Sec | NPT-HHMMSS NPT-SEC = 1 * DIGIT [" "* DIGIT] NPT-HHMMS = NPT-HH": "NPT-MM": "NPT-SS [". "* Digit] NPT-HH = 1 * Digit; Any Positive Number NPT-mm = 1 * 2Digit; 0-59 NPT-SS = 1 * 2Digit; 0-59
For example: nPT = 123.45-125 nPT = 12: 05: 35.3- nPT = NOW-grammar is based on ISO 8601. The NPT-SEC flag is automatically generated by the human NTP-HHMMSS logo. "Now" constants allow the client to wish to receive feedback from the site instead of the reserve or time delay version. Absolute time and 0 are not suitable for this situation, this thing is needed. 3.7 Absolute time absolute time is clear as an ISO 8601 time film. The second function using UTC can be pointed out. UTC-RANGE = "Clock" = "UTC-TIME" - "[UTC-TIME] UTC-TIME = UTC-date" T "UTC-TIME" Z "UTC-DATE = 8Digit;
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