CN106961630A - A kind of P2P streaming media video player methods optimized based on DASH - Google Patents

Abstract

The invention discloses a kind of P2P streaming media video player methods optimized based on DASH, step includes：1st, hardware system includes server, seed node group and the part of user node three, and user node is also known as peer；Step 2, server and seed node group prepare video slicing, and server generates the initial MPD file of burst, and seed node group obtains video resource, the server generation MPD files for accessing position more from server；Step 3, peer obtain video slicing and carry out adaptive identifying.The method of the present invention, it is ensured that the steady quality that P2P streaming media videos are played is reliable.

Description

A P2P streaming video playback method based on DASH optimization

technical field

The invention belongs to the technical field of P2P streaming media, and relates to a P2P streaming video playback method based on DASH optimization.

Background technique

P2P streaming media technology uses P2P peer-to-peer network architecture and P2P file exchange technology to realize multi-node simultaneous streaming and playback of digital media content. In the P2P streaming media system (streaming media playback system), the server only needs to send data to a small number of nodes, and these nodes can share the obtained data with other nodes, and each node can get high-quality data through the streaming media system. video service. P2P streaming media technology is divided into on-demand and live broadcast. In the on-demand service of the P2P streaming media system, the played media data has been recorded and stored on a fixed server, and the real-time requirements are not high. Users can exert various controls on the on-demand video programs, such as stop, pause, and fast forward. Wait.

However, driven by user demands and the diversification of terminal equipment, the Internet structure, especially the access network form, is becoming more and more abundant. The dynamic changes of the network are inevitable, and network differences have a great impact on the user's playback experience. Although the application of P2P streaming media technology in the streaming media system reduces the pressure on the server, improves the service capability of the system, and improves the user experience, it cannot cover up its shortcomings, such as copyright issues, security issues, and consumption of a large amount of bandwidth. In addition, a key issue is that the format of the video data blocks of the P2P streaming media system is not a public format, and some ready-made video playback technologies cannot be used, such as MSE extensions (Media Source Extensions, Media Source Extensions) of HTML5, etc. For decoding and playback, it needs a set of its own decoding and playback components.

In view of the above problems, the use of DASH (Dynamic Adaptive Streaming over HTTP, dynamic adaptive streaming media) technology can effectively solve these problems, because the DASH standard has been formulated and published, supports multiple streams of the same video content, supports audio and video technology, support live and on-demand, and support digital copyright security.

DASH technology is a cross-platform standard, instead of only supporting limited platforms and browsers, it is supported by almost all popular browsers. The DASH standard stipulates that the video is divided into independent blocks according to certain rules. These blocks are divided into initial blocks containing codec information and media data blocks. The initial block provides decoding information for the media data blocks, and each block is an open and unified structure. ; DASH will also generate a description file to describe the video stream, and these technical characteristics are very consistent with the characteristics of P2P streaming media technology. DASH technology can provide video fragmentation groups with multiple bit rates for media files to cover different network bandwidth requirements; thus, while ensuring the viewing effect, it reduces the client's stuttering and buffering, and has the ability of network self-adaptation. The digital copyright protection rules of DASH technology provide a new possibility to solve the copyright problem of video playback in P2P streaming media technology.

For the standard DASH video playback system, the server bears all the load of the system. When the number of clients continues to increase, the efficiency of the server will obviously decrease; Changes, when the peer is receiving and playing, the playback will freeze or stop broadcasting. Continuous freezes are intolerable to users. If DASH and P2P streaming media technology are combined, it not only solves the load pressure and failure risk of DASH technology on the central server, but also solves some difficulties in the use of P2P streaming media technology, such as simplifying the development of P2P video client, which makes the two The combined system appears to have clear advantages.

Contents of the invention

The purpose of the present invention is to provide a P2P streaming video playback method based on DASH optimization, which solves the problems of playback freeze and stoppage caused by unstable network environment at the user end.

The technical scheme adopted in the present invention is, a kind of P2P stream media video playing method based on DASH optimization, implement according to the following steps:

Step 1. The hardware system includes three parts: server, seed node group and user nodes. User nodes are also called peers;

Step 2. The server and seed node group prepare video fragmentation

2.1) The server generates the initial MPD file of the fragment

The server slices the video file according to the DASH protocol to generate the initial MPD file;

2.2) The seed node group obtains video resources from the server

The seed node group registers with the server and requests the initial MPD file, parses the initial MPD file to obtain video resource information, selects the video resource to download according to its own ability, and once a certain video is selected, downloads the entire set of video fragments to the local;

2.3) The server generates MPD files with multiple access locations

The server monitors the seed node group, after the seed node group downloads the initial MPD file, summarizes the video resource information owned by the seed node group, generates an MPD file with multiple access locations, and waits for the peer to download;

Step 3. Peer obtains video fragments and performs adaptive playback

3.1) When the peer starts downloading, it first requests the video from the server, and after receiving the MPD file from the server, it parses and obtains the code rate, maximum bandwidth, minimum bandwidth, resolution and several access location information of the video fragment , and then select the appropriate bit rate and access location according to the network environment to start downloading video fragments;

3.2) The peer caches a small amount of video fragments and starts playing, downloads subsequent video fragments while playing, and counts the fragments cached locally into a resource table for interaction with other peers; The basic information attribute of the slice is a column to create a resource table;

3.3) Each time the peer downloads the next fragment, it generates a unified query message according to the resource table, sends it to neighbor peers for fragment query, and according to the query result, parses the access location from its neighbor peer and MPD file Determine the download location and download via the HTTP protocol.

The beneficial effects of the present invention are that the fragmentation method of DASH is applied to the P2P streaming media system, compared with the traditional P2P streaming media system, the use of this method can introduce the code rate adaptive technology of DASH into the P2P streaming media system, without Changing the load balancing characteristics of the P2P streaming media system not only solves the problem of a single load, but also enables the peer in the P2P streaming media system to adapt to the bit rate as the network environment changes when playing video, which solves the problem of the network environment of the client. Stability caused problems such as playback freezes and stoppages, which improved the playback fluency and improved the user's playback experience. Most importantly, the method of the present invention makes it possible to realize video playback in the P2P streaming media system without installing any plug-ins and clients in the Web environment.

Description of drawings

Fig. 1 is the overall structure general diagram of the inventive method;

Fig. 2 is a schematic diagram of the principle of segment downloading in the method of the present invention.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

In general, in the DASH system, video resources are stored on the server, and video fragments can only be accessed on the server, but it is also possible to store video resources on multiple servers in order to reduce server pressure, so that the same video fragment Can be accessed in multiple locations. In the P2P streaming media system, video resources can be stored not only on the server, but also on the user node, which is just in line with the situation that the same segment has multiple access locations in the DASH system.

In MPD, the BaseURL element can specify one or more public location information for slices and other resources. According to the description in the DASH standard, BaseURL can appear in the MPD level, Period level, Adaptation Set level and Representation level in the MPD file. The same shard can be accessed in multiple locations if an alternate base shard URL is provided in the BaseURL element at any level; then, by providing an alternate shard URL in the BaseURL at some level in the MPD file Multiple location access. In the system, both the server and the seed node group have video data, and the same segment has multiple access locations. Once the seed node downloads a certain video, it will download all the segments of the video, so the data stored on the seed node The video data is complete and identical to that on the server, so multiple segment URLs can be provided in the MPD-level BaseURL.

The present invention is based on the DASH optimized P2P streaming video playback method, based on the above-mentioned principle, concrete implementation according to the following steps:

Step 1. The hardware system includes three parts: server, seed node group and user node

As shown in Figure 1, the server provides the original multimedia resources of video playback, is responsible for generating MPD files with video fragmentation, and serves the seed node group and user nodes; the seed node group includes a plurality of seed nodes (such as seed node 1 in Figure 1 , seed node 2, seed node 3), each seed node obtains part of the video resource from the server, saves it locally, and downloads it for the user node; the user node is called Peer in the P2P system, including multiple Peers (such as Fig. 1 Peer A, Peer B, Peer C), the user node is the terminal for receiving, decoding and playing video, and each Peer obtains video fragments from the server, seed node group or its adjacent peers to play;

Step 2. The server and seed node group prepare video fragmentation

2.1) The server generates the initial MPD file of the fragment

The server slices the video file according to the DASH protocol to generate the initial MPD file;

2.2) The seed node group obtains video resources from the server

The seed node group registers with the server and requests the initial MPD file, parses the initial MPD file to obtain video resource information, and selects video resources for download according to its own capabilities. Once a certain video is selected, the entire set of video fragments (including multiple bit rates) are segmented. Download all to local;

2.3) The server generates MPD files with multiple access locations

The server monitors the seed node group, after the seed node group downloads the initial MPD file, summarizes the video resource information owned by the seed node group, generates an MPD file with multiple access locations, and waits for the peer to download;

Step 3. Peer obtains video fragments and performs adaptive playback

3.1) When the peer starts downloading, it first requests the video from the server, and after receiving the MPD file from the server, it analyzes and obtains the code rate, maximum bandwidth, minimum bandwidth, resolution, and several access locations of the video fragment, etc. Information, and then select the appropriate bit rate and access location according to the network environment to start downloading video fragments;

3.2) The peer caches a small amount of video fragments and starts playing, downloads subsequent video fragments while playing, and counts the fragments cached locally into a resource table for interaction with other peers; The basic information attribute of the slice is a column to create a resource table;

The basic information attributes of the segment include: bit rate, resolution, segment name and segment URL, and the resource table is used for neighboring peers to query each other for the video segments they need.

3.3) Each time the peer downloads the next fragment, it generates a unified query message according to the resource table, sends it to neighbor peers for fragment query, and according to the query result, parses the access location from its neighbor peer and MPD file Determine the download location and download via the HTTP protocol.

The working principle of the method of the present invention is to disperse video resources into the system, and share the burden of the server by the seed node group and ordinary user nodes: the server slices the video according to the DASH protocol, distributes it to the seed node group, and generates multiple The MPD file of the access location is provided to the peer to download and play; the peer downloads the MPD file of the multi-access location from the server, analyzes and obtains multiple code rates and multiple access locations of the required fragments, and at the same time inquires whether there are required fragments from its neighbor nodes. Then select the appropriate code rate according to the network, and download and play video fragments from the server, seed node group or its neighbor nodes through the HTTP protocol. The specific process is shown in Figure 2. Figure 2 shows the whole process of how a certain Peer in the P2P network obtains video fragments from the server, seed host and other Peers to play.

Example

1. MPD files with multiple access locations

In this embodiment, there are three sources of content described in the MPD file (seed1, seed2 and seed3), and five versions of different bit rates and resolutions of the video are provided, and the bit rate is between 512kbit/s and 2Mbit/s. An example of the partial content of an MPD file with three access locations is as follows:

2. Resource table

Since Peer's cache is limited, there will not be many records in the table, and maintenance is not difficult. Table 1 is the specific setting of a resource table.

Table 1. The specific setting structure of the resource table

It can be seen from Table 1 that the peer caches some video fragments of two video resources, and video 1 caches the third and fourth video fragments, and the code rate and fragmentation rate of the two video fragments are different; Video 2 caches the seventh, eighth and ninth video fragments, the seventh and eighth video fragments have the same bit rate and resolution, and the ninth video fragment has a higher bit rate and resolution. When receiving the query video segment information, determine the unique segment according to the code rate, resolution and video segment name. If the corresponding video fragment is found, the URL information of the fragment is returned, otherwise the search fails.

Claims (3)

1. a kind of P2P streaming media video player methods optimized based on DASH, it is characterised in that implement according to following steps：

Step 1, hardware system include server, seed node group and the part of user node three, and user node is also known as peer；

Step 2, server and seed node group prepare video slicing

2.1) server generates the initial MPD file of burst

Video file is cut burst by server according to DASH agreements, generates initial MPD file；

2.2) seed node group obtains video resource from server

Seed node group is to server registration and asks initial MPD file, parses initial MPD file and obtains video resource information, Select video resource to be downloaded according to self-ability, once have selected certain video, just all download its a whole set of video slicing To local；

2.3) the server generation MPD files for accessing position more

Server monitoring seed node group, after the initial MPD file of seed node group download is finished, collects seed node group and possesses Video resource information, the generation MPD files for accessing positions wait peer to download more；

Step 3, peer obtain video slicing and carry out adaptive identifying

3.1) when peer starts to download, first to server request video, receive after the MPD file that server is sent, parsing is obtained Several to the code check of video slicing, maximum bandwidth and minimum bandwidth, resolution ratio and burst access positional information, Ran Hougen Suitable code check and access position is selected to start foradownloaded video burst according to network environment；

3.2) peer is commenced play out after caching a small amount of video slicing, downloads subsequent video burst when playing, and be buffered in Local burst is counted in a resource table, to be interacted with other peer；With video resource mark and burst essential information Attribute sets up resource table for row；

3.3) when peer downloads next burst every time, unified query messages is generated according to resource table, neighbours peers is sent to The inquiry of burst is carried out, and according to Query Result, under being determined in the access position parsed from its neighbours peer and MPD file Position is carried, is downloaded by http protocol.

2. the P2P streaming media video player methods according to claim 1 optimized based on DASH, it is characterised in that：It is described Step 1 in,

Server provides the initial multimedia resource of video playback, is responsible for video slicing generating MPD file, is seed node group With user node service；

Seed node group includes multiple seed nodes, and each seed node fetching portion video resource at server is stored in Locally, downloaded for user node；

User node is referred to as Peer, including multiple Peer in P2P systems, and user node is reception, decoding and plays video Terminal, each Peer obtains video slicing at server, seed node group or its adjacent peer and played out.

3. the P2P streaming media video player methods according to claim 1 optimized based on DASH, it is characterised in that：It is described Step 3.2) in, burst essential information attribute include code check, resolution ratio, burst name and burst URL, resource table be used for neighbours The video slicing mutually inquired about needed for oneself between peer.