What are the protocols used for streaming media

Question 1: What protocols are used for streaming media? Transmission protocols for streaming media

When people watch online movies or TV, they usually notice that the connections to these files don't start with or ftp, but something that starts with rtsp or mms, why is that? In fact, these and and ftp are the same protocols for data transmission over the network, only they are protocols specialized for streaming media. Here, let's look at the main streaming protocols in use today:

1. RTSP (Real Time Streaming Protocol), the real-time streaming protocol, which was proposed by RealNetworks and Netscape*** together and is now used in RealNetworks' Real PNM (Progressive Networks Audio), which is also a Real-specific real-time transport protocol, generally uses the UDP protocol and occupies port 7070, but when your server is inside a firewall and port 7070 is blocked, and your server has SmartingNetwork set to true, the protocol is used. However, when your server is inside a firewall and port 7070 is blocked, and your server has SmartingNetwork set to true, it uses the protocol and occupies the default port 80;

3. MMS (Microsoft Media Server protocol), which is Microsoft's streaming media server protocol, and MMS is the default method of connecting to the Windows Media Unicast service.

Having introduced the main three, you might also ask which protocol Apple's QuickTime uses. For the most part, QuickTime uses the protocol, but it is actually also powered by the standard streaming transport protocol, which is the standard RTSP protocol, which Real uses as its own developed version of RTSP.

In streaming media transmission, the standard protocols are RTP (Real time Transport Protocol, real-time transport protocol), RTCP (Real-time Transport Control Protocol, real-time transport control protocol), RTSP (Real Time), and RTSP (Real Time Streaming Protocol, real-time streaming protocol). Streaming Protocol), RTSP (Real Time Streaming Protocol) and RSVP (Resource Reserve Protocol), vendors' products are based on these protocols for research and development, limited to space, we will not discuss in depth here.

Question 2: What are the three parts of a streaming media system? What are the three major mainstream media formats and protocols? 1, encoder: it consists of an ordinary computer, a microvision high-definition video capture card and streaming media encoding software. microvision streaming media capture card is responsible for the audio and video information sources into the computer for encoding software processing; encoding software is responsible for streaming media capture card transmitted digital audio and video signals compressed into a streaming media format. If you do live, it is also responsible for real-time compressed streaming media signals uploaded to the streaming media server

2, the server: by the streaming media software system server part and a hardware server. This part is responsible for managing, storing and distributing the streaming media programs uploaded by the encoder. 3, terminal player, also known as the decoder: this part of the streaming media system by the playback software and an ordinary PC, with which to play the user wants to watch the streaming media server on the video program.

Principles of Streaming Media Technology

Currently there are three mainstream streaming media technologies, RealNetworks' RealSystem, Microsoft's WindowsMediaTechnology, and Apple's QuickTime, which have their own proprietary algorithms, proprietary file formats, and even proprietary video formats. algorithms, proprietary file formats and even proprietary transmission control protocols.

Question 3: What are the common streaming protocols? There are MMS, RSVP, RTSP, RTP, RTPC, and so on

Question 4: What is streaming media? What are the types? Streaming media, also known as streaming media, is media that is broadcast while being transmitted and is a type of multimedia. Streaming media refers to the media provider in the network transmission of media "at the same time", the user while constantly receiving and watching or listening to the media being transmitted. The "streaming" of "streaming" media refers to the way in which the media is delivered (the way it is streamed), not to the media itself.

There are two types;

1. Sequential streaming is a sequential download in which the user can watch the online media while the file is being downloaded, and at a given moment in time, the user can only watch the portion of the file that has been downloaded, and cannot jump to the previous portion of the file that has not been downloaded yet. Sequential streaming is not like real-time streaming in that it adjusts to the speed of the user's connection during transmission. Because standard HTTP servers can send files in this form and no other special protocols are required, sequential streaming is more suitable for high-quality short clips such as credits, end credits, and commercials, and because the portion of the file that is viewed before it is played is downloaded losslessly, this method guarantees the final quality of the movie playback.

2. Real-time streaming refers to ensuring that the bandwidth of the media signal matches the network connection so that the media can be viewed in real time. Real-time streaming is different from HTTP streaming in that it requires a dedicated streaming server and transport protocol. Live streaming is always delivered in real time, making it particularly suitable for live events, and also supports random access, allowing users to fast-forward or rewind in order to view previous or subsequent content. Theoretically, a live stream can be played without stopping, but in practice, periodic pauses may occur. Real-time streaming must match the bandwidth of the connection, which means that image quality is poor at modem speeds. Also, video quality is poor when the network is congested or has problems because information lost in errors is ignored. To ensure video quality, sequential streaming might be better.

Question 5: What is the difference between the streaming protocols RTMP, RTSP, and HLS What is the difference between the streaming protocols RTMP, RTSP, and HLS?

HLS (HTTP Live Streaming)

Apple's dynamic bit rate adaptation technology. Mainly used for audio and video services on PCs and Apple terminals. It includes a m3u(8) index file, a TS media slice file, and a key encryption string file.

Commonly used streaming protocols include HTTP progressive download and RTSP/RTP-based real-time streaming protocols, which are basically completely different things, and are currently more convenient and easier to use with the HTTP progressive download method. Among them, HTTP Live Streaming from Apple is the representative of this aspect. It was originally developed by Apple for mobile devices such as iPhone, iPod, iTouch and iPad. It's now seen a lot of use on the desktop, and HTML5 supports it directly.

But the HLS protocol's slicing approach generates a large number of files, and storing or processing these files wastes a lot of resources. If a time shift of several days is to be realized, the indexing volume will be a huge number and significantly affect the speed of requests. As a result, the HLS protocol is quite demanding in terms of storage I/O requirements. There are also companies that have come up with very good solutions for this.

The new on-demand server system, with its original memory cache data real-time slicing technology, subverts this traditional implementation method, and fundamentally solves the problem of fragmentation of a large number of slices, so that the slicing and packing capacity of a single server is no longer a bottleneck. The basic principle is as follows:

Instead of storing the TS slice file on disk, it exists in the memory, which makes the server's disk no longer have "tons" of file fragments, greatly reduces the number of I/O times of the disk, prolongs the service life of the server disk, and greatly improves the stability of the server's operation. Stability. At the same time, by using this technology, endpoints request data directly from the server's memory, which greatly improves the response time to endpoint data requests and optimizes the video viewing experience.

The RTSP protocol, which is supposed to be the best for real-time, is a good choice if you want to have high real-time requirements, such as 0.5s or less. A while ago, I wrote a proposal to imitate spydroid rtsp server, in fact, is options, describe, setup, play, pause, teardown these steps, this protocol is the most widely used, the online introduction is also more. To really understand the rtsp protocol in depth, you can check out live555 if you have good c++ language skills.

Question 6: What are the main protocols for streaming media delivery? What are the functions and tasks of each Based on Windows Media technology streaming media system design and implementation

Abstract: This paper in the introduction to streaming media technology and its Windows Media technology based on the actual brief description of the installation of the Windows Media server, the production of the ASF file and the "On-demand unicast release point", "broadcast unicast release point", "multicast broadcast station" creation method, from a practical point of view to explain the realization of streaming media services in the network of technology and methods.

Keywords

Keywords: Windows Media, streaming media, network video

Windows Media-based streaming media technology, Design and Implementation

Abstract: This article profiles in streaming media technology in the network. profiles in streaming media technology in its Windows Media technology on the basis of the actual bined on a Windows Media server installation, ASF, as well as the production of documents on-demand unicast release point, Broadcast Unicast release point, Multicast broadcast stations, the creation of They may be related to the test, from the perspective of the practice described in the network to achieve streaming media services technologies and methods. streaming media services technologies and methods.

Key words: Windows Media streaming video network

1. Streaming media is simply continuous time-based media, such as audio, video, or multimedia files, transmitted over the Internet/Intranet using streaming technology. Streaming media does not download the entire file before playback, only the beginning of the part of the content stored in memory, streaming media data streams at any time to transmit at any time to play, only at the beginning of some delay. The key technology to realize streaming media is streaming transmission. Streaming mainly refers to the general term for the technology of transmitting media (e.g., video, audio) over a network. Its specific meaning is the transmission of film and television programs to a PC via the Internet. Streaming media technology is a comprehensive technology that includes a number of technologies such as acquisition, encoding, transmission, storage, decoding and so on.

2. Introduction to Windows Media Technology

2.1 Characteristics

The Windows Media technology introduced by Microsoft is characterized by convenience, advancement, integration, and low cost, and its production, distribution, and playback software is integrated with Windows NT/2000/9x, requiring no additional purchase. Microsoft's streaming video solution is free on the Microsoft Windows platform, and the video and audio quality of both the production side and the player are excellent and easy to use.

2.2 Windows Media playback methods

Windows Media playback methods include unicast, multicast, on-demand, and broadcast. Their meanings are shown in the following table:

Unicast: is a point-to-point connection between a client and a server. A separate data channel is established between the client media servers, and each packet sent by 1 server can only be transmitted to 1 client.

Multicast: is the delivery of a stream of content over a multicast-enabled network, where all clients*** in the network enjoy the same stream. Built by multicast technology ...... >>

Question 7: What is a streaming media playback protocol Streaming Media Technology Fundamentals - Streaming Media Transport Protocol

Author/Source: Unknown

Real-time Transport Protocol RTP and RTCP

RTP (Real-timeTransportProtocol) is a transport protocol used for Internet RTP (Real-timeTransportProtocol) is a transport protocol for multimedia data streams over the Internet.RTP is defined to work in one-to-one or one-to-many transport situations, and its purpose is to provide timing information and synchronize streams.RTP typically uses UDP to transport data, but RTP can work on top of other protocols such as TCP or ATM. Two ports will be used when an application starts an RTP session: one for RTP and one for RTCP.RTP by itself does not provide a reliable delivery mechanism for delivering packets sequentially, nor does it provide flow control or congestion control; it relies on RTCP to provide these services. Typically the RTP algorithm is not implemented as a separate network layer, but as part of the application code. Real-time Transport Control Protocol RTCP: RTCP (Real-timeTransportControlProtocol) provides flow control and congestion control services along with RTP. During an RTP session, each participant periodically transmits RTCP packets, which contain statistics such as the number of packets sent, the number of packets lost, etc., and can therefore be used by the server to dynamically change the transmission rate or even the payload type. rtcp and rtcp are used in conjunction with each other, and they can be used to optimize the efficiency of the transmission with effective feedback and minimal overhead. and are thus particularly well suited to transferring real-time data over the Web.

6.2.1 RTP Data Transfer Protocol

RTP provides end-to-end network transfer capabilities suitable for the delivery of real-time data, such as video, audio, and simulation data, over multicast and on-demand.RTP does not address real-time services such as resource reservation and quality assurance, and RTCP expands the data transfer to allow for the monitoring of data transfers, with minimal control and identification.RTP and RTCP are designed for independent transfer and identification. RTCP are designed as separate transport and network layers.

2.1.1 RTP Fixed Header

The RTP header format is as follows:

----------------------------------------------------------------------------------------- ------

|V=2|P|X| CC |M| PT | Serial Number |

----------------------------------------------------------------------------------------- ------

| Time Scale |

-----------------------------------------------------------------------------------------------

| Synchronization Source Recognition (SSRC) |

-----------------------------------------------------------------------------------------------

| Role Recognition (CSRC) |

| .... |

-----------------------------------------------------------------------------------------------

The first 12 octets appear in every RTP packet, while the CSRC identifier list appears only when the mixer is inserted.

2.1.2 Multiplexing RTP Connections

For the protocol to operate efficiently, the number of multiplexing points should be minimized.In RTP, multiplexing is provided by defining the destination transport address (network address versus port number) of the RTP connection. For example, for teleconferencing where audio and video are encoded separately, each medium is carried in a separate RTP connection with its own destination transport address. Instead of placing audio and video in a single RTP connection, the destination is multiplexed based on the SSRC segment load type. Using the same SSRC , ...... >>

Question 8: What is the difference between the streaming protocols RTMP, RTSP and HLS RTMP is an acronym for Real Time Messaging Protocol. The protocol is based on TCP and is a family of protocols, including RTMP basic protocol and RTMPT/RTMPS/RTMPE and many other variants.RTMP is a network protocol designed for real-time data communication, mainly used for audio/video and data communication between Flash/AIR platforms and streaming/interactive servers that support RTMP protocol. Software that supports this protocol includes Adobe Media Server/Ultrant Media Server/red5 and others.

RTSP (Real Time Streaming Protocol), RFC2326, Real-Time Streaming Transport Protocol, is an application-layer protocol in the TCP/IP protocol family, an IETF RFC standard submitted by Columbia University, Netscape, and RealNetworks. The protocol defines how a one-to-many application can efficiently deliver multimedia data over an IP network.RTSP sits on top of RTP and RTCP in terms of architecture, and it uses either TCP or UDP to accomplish the data transfer.HTTP is compared to RTSP, in which an HTTP request is sent by the client and responded to by the server; with RTSP, both the client and the server can send the request, i.e. RTSP can be bi-directional.RTSP is used to control the sound or video multimedia streaming protocol, and allows simultaneous control of multiple streaming requirements, the transmission of the network communication protocol used is not in the scope of its definition, the server can choose to use TCP or UDP to transmit streaming content, its syntax and operation is similar to HTTP 1.1, but does not particularly emphasize the time synchronization, so the It is similar to HTTP 1.1 in syntax and operation, but does not emphasize time synchronization, so it is more tolerant of network latency. As mentioned above allows simultaneous multiple streaming demand control (Multicast), in addition to reducing the server-side network usage, and thus support multi-party video conferencing (Video Conference).

Question 9: the development of real-time streaming media RTSP protocol, which books to read can look at live555, that code inside the rtsp, the process is very clear, very good understanding

If you want to do the streaming media client, you may use directshow

Question 10: the control protocol for mobile streaming media Streaming media using the unique The application and control protocols used by streaming media are RTP/RTCP, RSVP, and RTSP.(1) Real-Time Transport Protocol (RTP) and Real-Time Control Protocol (RTCP).RTP/RTCP is an IP-based application layer protocol that supports the transmission of real-time data (audio and video streaming), and the idea is to transmit the real-time data and at the same time send some feedback on the quality of transmission and reception, which are two tasks performed by RTP and RTCP respectively. RTP provides mechanisms for time reconstruction, timing, packet loss detection, and reordering.RTP supports both unicast and multicast, and can be used for unidirectional or bidirectional services, but RTP itself does not provide mechanisms for how to transmit in real time, nor does it provide reliable flow-blocking control, but rather, it optimizes the efficiency of the transmission by cooperating with RTCP and UDP.RTP/RTCP is an IP-based application layer protocol that supports real-time data (audio and video streams) transmission while sending some feedback on the quality of the transmission and reception, and these two tasks are accomplished by RTCP and RTP, respectively. RTP/RTCP provides the required functionality and control mechanisms for transmitting real-time data, but is not itself responsible for high-level tasks such as reordering and synchronization, which are done by the application. (2) Resource Reservation Protocol (RSVP).RSVP allows data receivers to request special end-to-end QoS for data streams.Real-time applications use RSVP to reserve the necessary resources on the router so that the required bandwidth is available at the time of transmission.The RSVP process is monolithic and does not discriminate between senders and receivers.RSVP supports both multicast and unicast and adapts to varying membership numbers and routing. routing. Using RSVP requires that all nodes on the transmission path support RSVP, which is difficult to guarantee, so streaming applications generally do not use RSVP.(3) Real-Time Streaming Protocol (RTSP).RTSP is an application-layer protocol that can be utilized to create and control continuous streams of audio media and video media between servers and clients for "network remote control", providing remote control of audio and video similar to a VCR. But RTSP has to be transported in a data-independent channel.RTSP supports both unicast and multicast and provides methods for selecting the transport channel, with a choice of UDP, multicast UDP, and TCP, whereas the lower-layer transport mechanism relies on either RTP or TCP.RTSP operates in coordination with lower-layer protocols (e.g., RTP, RSVP) to provide a full streaming service.RTSP is stateful.RTSP is a stateful, RTSP is a stateful, symmetric protocol in which the RTSP server maintains session state and requests can be made by both the media server and the client in RTSP. The syntax and operation of RTSP is similar to that of HTTP, and it uses URLs similar to those in HTTP that are dedicated to audio and video.