CN107704687B

CN107704687B - Video monitoring system aided design and evaluation method

Info

Publication number: CN107704687B
Application number: CN201710942494.9A
Authority: CN
Inventors: 张莉; 张磊
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2017-10-11
Filing date: 2017-10-11
Publication date: 2021-11-02
Anticipated expiration: 2037-10-11
Also published as: CN107704687A

Abstract

The invention discloses a method for designing a physical topological model of an auxiliary design system and performing simulation evaluation in the field of video monitoring, and relates to the technical field of modeling and simulation. Firstly, constructing an evaluation model of a video monitoring system, defining a modeling language VSML, realizing a visual modeling tool, designing a physical topology model with correct logic, and generating a corresponding OTCL script file; selecting simulation software NS2, expanding, using OTCL script file and external video stream data as NS2 simulation input, executing simulation by using expanded NS2 simulation tool, recording simulation process data, and finally outputting video stream data. And according to the acquired simulation process data, counting an evaluation result according to the evaluation model. According to the invention, a visual modeling tool is used for providing a convenient method for designers in the field of video monitoring systems to design the physical topological structure of the video monitoring system; the evaluation result evaluates the design scheme of the video monitoring system from multiple aspects, and is more comprehensive and meets the requirements of users.

Description

Video monitoring system aided design and evaluation method

Technical Field

The invention relates to the technical field of modeling and simulation, in particular to a method for designing a physical topological model of a system in an auxiliary mode and performing simulation evaluation in the field of video monitoring.

Background

With the increasing importance of the society on security systems and the popularization of computers and networks, video monitoring technology has been developed rapidly. From the first generation of analog video monitoring system to the third generation of video monitoring system based on IP network, the technical framework and system of video monitoring are continuously changed, and the requirements of users on the functions and performance of the video monitoring system are more personalized. The scale of the video monitoring system is gradually increased, the deployment environment is more complex, the hardware types of the video monitoring system are more, and the performance attributes are different. The traditional hardware architecture has high risk of testing after deployment, and the requirement of carrying out simulation verification on a physical topology model in a design stage is particularly important.

The existing video transmission quality evaluation framework, such as Evalvid, myEvalvid, SVEF, etc., mainly evaluates the quality (definition) of transmitted video, and cannot evaluate the network performance, cost, and other concerns of users. Meanwhile, the frames can only evaluate the video transmission quality between single points, and cannot simulate the transmission in the physical topology of a complex video monitoring system.

The combined use of modeling and simulation techniques may solve the above-described problems. An evaluation model based on a video monitoring system design scheme is oriented to the field of video monitoring systems for visual modeling, and field designers are assisted to design a physical topology scheme; and (4) executing simulation operation on the established model to obtain data of each relevant parameter, and analyzing and obtaining an evaluation result.

The model provides an overall design for the system, and can describe the system in terms of system structure, organization, behavior and action. Modeling is a description, simulation and abstraction of a real-world system, following the principles: practical, clear in structure, proper in precision and standardized as much as possible. The modeling facing the field of video monitoring systems serves video monitoring system designers to simplify the expression of the physical topological graph of the system by providing visual and easy-to-use modeling symbols. Meanwhile, the model can describe the attribute to be evaluated and can perform simulation operation.

Unified Modeling Language (UML), also known as Unified Modeling Language, is a current object-oriented standardized Modeling Language. The UML configuration diagram (deployment diagram) consists of two parts, namely nodes and relations, and can clearly show the physical topological structure between software and hardware of the system. However, the UML is not directly used for modeling the design scheme of the video monitoring system, because the UML is not specific to the video monitoring system, and the modeling symbol of the UML is not easy to understand for the field designer; in addition, for the personalized requirements and simulation requirements of the design scheme, UML cannot be fully satisfied.

Instead of studying the actual object, simulation is carried out by studying a model that represents the object under study. With the development of science and technology, the requirements of high efficiency and low cost cannot be met by a material object experiment, and the problem is well solved by computer simulation. And (3) running a model to be simulated on the simulation software by utilizing the simulation software, and analyzing the process and the output information to comprehensively evaluate the actual system. For a video monitoring system, due to the characteristics of complexity, high cost and the like, the method is very suitable for evaluating whether a physical design model meets requirements or not by adopting a simulation mode.

Currently, mainstream simulation software widely applied comprises OPNET, NS2, MATLAB and the like, and NS2 is used as a source-opening software and has rich component libraries and flexible configuration. Due to the adoption of c + + development, the NS2 has high execution efficiency and good expansibility. The defects are that the door entry difficulty is high and no graphical interface exists. Compared with other commercial simulation software such as OPNET, the NS2 has low cost and wide application range, and is more suitable for network technology simulation research.

Disclosure of Invention

Aiming at the characteristics of multiple hardware types and brands, different functional attributes, complex deployment environment and the like of the current video monitoring system and considering the personalized requirements of system users, video monitoring system designers can face multiple design schemes, the conventional process determines that system testing can be carried out only after the system is completely deployed based on a hardware architecture, and once the system does not meet the requirements, the hardware replacement cost is high, and even the risk that the whole system needs to be reconstructed is faced. The invention provides an auxiliary design and evaluation method for a video monitoring system, which can simply and efficiently solve the problems, so that a professional designer can evaluate whether a designed solution can meet the requirements of a user from multiple aspects in a design stage.

The invention provides an auxiliary design and evaluation method of a video monitoring system, which comprises the following implementation steps:

the method comprises the following steps: and constructing an evaluation model of the video monitoring system according to the user requirements and the industry standard of the video monitoring field.

Step two: a modeling language VSML (video Surveillance Model language) for video monitoring system design is defined. The VSML modeling language is obtained based on UML2.0 configuration diagram extension, faces the field of video monitoring, and can be used for describing a physical topology model of a video monitoring system.

Step three: the visual modeling tool for the field of video monitoring systems is realized. The tool is used for editing and designing a physical topological model of the video monitoring system and generating a model script file of simulation input.

Step four: and designing a logically correct physical topology model of the video monitoring system by the video monitoring system designer according to the user requirements by using the visual modeling tool.

Step five: and generating a corresponding OTCL script file according to the physical topology model designed in the step four.

Step six: selecting simulation software NS2, and extending NS 2. The method mainly extends the relevant interfaces of the application layer and the transport layer of the NS2, including three parts of video data reading, sending, transmitting and receiving.

Step seven: and inputting the OTCL script file obtained in the step five and the external video stream data as NS2 simulation input.

Step eight: and performing simulation by using the expanded NS2 simulation tool, recording simulation process data, and finally outputting video stream data.

Step nine: and according to the acquired simulation process data, counting an evaluation result according to the evaluation model.

In the ninth step, the statistical evaluation result includes:

(1) comparing the original video stream input to the NS2 with the output video stream of the NS2, and evaluating the video transmission quality, wherein the adopted quantization indexes comprise MOS and PSNR;

(2) acquiring network transmission related index data under a simulation environment according to a transmitting end tracking file and a receiving end tracking file acquired in the NS2 simulation, and evaluating network transmission performance, wherein the adopted quantitative indexes comprise network delay, throughput, packet loss rate, false packets and packet jitter;

(3) traversing the OTCL script file, acquiring the functional attributes of all nodes, evaluating the functional satisfiability of the system, counting the functions owned by all the nodes by adopting a quantitative index, and judging whether the designed video monitoring system meets the functions required by a user;

(4) and traversing the OTCL script file, counting the lattice attributes of all nodes, and evaluating the system cost.

The invention has the advantages and positive effects that: (1) the method is visual, simple and effective, and provides a convenient method for designers in the field of video monitoring systems to design the physical topological structure of the video monitoring system through a visual modeling tool; (2) the method executes simulation verification on the system physical topology model, and obtains attribute data to be evaluated according to the video monitoring system evaluation model provided by the invention to obtain an evaluation result. The evaluation result evaluates the design scheme of the video monitoring system from multiple aspects, and is more comprehensive and meets the requirements of users.

Drawings

FIG. 1 is a schematic overall flow chart of an aided design and evaluation method of a video surveillance system according to the present invention;

FIG. 2 is a diagram of a system for evaluating indexes of a video surveillance system in a first step of the present invention;

FIG. 3 is a schematic diagram of a VSML element model in step two of the present invention;

FIG. 4 is a schematic diagram of a prototype visual modeling tool in step three of the present invention;

FIG. 5 is an expanded view of the standard NS2 in step six of the present invention;

fig. 6 is a schematic diagram of a simulation flow in step eight of the present invention.

Detailed Description

To facilitate an understanding and practice of the invention by those of ordinary skill in the art, specific embodiments thereof will now be described with reference to the accompanying drawings.

The traditional video monitoring system design scheme can only test and evaluate whether the actual hardware architecture meets the requirements after the actual hardware architecture is completely deployed, and the risk is high. The problem is solved by using the video monitoring system aided design and evaluation method, so that designers in the field can provide a physical topology design scheme in a design stage and evaluate the scheme according to an evaluation model. Fig. 1 shows the overall process of simulation design and evaluation of the video surveillance system of the present invention. The video monitoring system design scheme evaluation model in fig. 1 is obtained according to user and market requirements, and mainly includes four requirements of video transmission quality analysis, network transmission performance analysis, function satisfiability check and system cost statistics. The model is a reference basis for modeling and simulation evaluation of the design scheme of the video monitoring system. Firstly, designing a physical topology scheme of a video monitoring system with correct logic by using a visual modeling tool according to requirements of functions, cost and the like; then, in order to carry out simulation operation on the model, the visual modeling tool can generate a corresponding OTCL script file according to the model; the script will then be used as an input of an extended NS2 simulation tool, and in the NS2 environment, on one hand, simulation software will perform simulation operation on the physical model represented by the OTCL script file, and on the other hand, the OTCL script file will be directly analyzed for statistics of system cost and checking functional satisfiability. In the simulation operation of the NS2, data such as network delay, packet loss rate, and the like can be acquired through analysis of the trace file, and used for evaluation of network transmission performance. By comparing the original input video stream with the output video stream, the data of PSNR (Peak Signal to Noise Ratio) and MOS (Mean Opinion Score) can be obtained for video transmission quality analysis. And finally, obtaining an evaluation result of the physical topological structure of the video monitoring system design scheme according to the data acquired in the whole process.

FIG. 1 is a flow chart showing the steps of implementing the method of the present invention, and the specific steps are described in detail as follows:

step P01: the method comprises the steps of determining an evaluation model of a video monitoring system design scheme, and determining attributes to be evaluated of the design scheme by establishing the evaluation model. According to the system requirements concerned by users, and with reference to video quality analysis and network performance related standards, determining a video monitoring system index evaluation system, and evaluating corresponding attributes by adopting quantifiable indexes. Meanwhile, an evaluation model of the video monitoring system design scheme is formed by combining the relevant parameters and the index range.

By summarizing the working principle of the video monitoring system and researching and summarizing the user requirements, the video transmission quality, the transmission network performance, the function satisfiability and the system cost are the most concerned aspects. Fig. 2 is an evaluation model diagram, wherein the video transmission quality is mainly expressed as definition, the transmission network performance is expressed as real-time performance and fluency, the function is expressed as the function satisfiability of hardware in the overall physical topological diagram, and the cost is expressed as the statistics of the physical hardware cost. It can be seen that in order to perform quantitative evaluation on the video monitoring system design scheme, a value comprehensive analysis is performed on each item by using a specific attribute. The video transmission quality evaluation adopts two attribute values of MOS (Mean Opinion Score-Mean subjective Opinion Score) and PSNR (Peak Signal to Noise Ratio-Peak Signal to Noise Ratio), and carries out comprehensive evaluation analysis by referring to PSNR/MOS parameters and an index table in a table 1; the evaluation indexes of the network transmission performance comprise packet loss rate, average time delay, throughput and the like, and the network performance parameters and indexes in the table 2 are referred; the function satisfiability is that functions which can be satisfied by all nodes, such as a playback function, a storage function and the like, are counted by traversing all hardware nodes in a physical topology model of the design scheme; the statistical method of the cost is consistent with the functional satisfiability, and the price of hardware represented by all nodes is counted.

TABLE 1 PSNR/MOS parameters and indices

TABLE 2 Chinese communication industry Standard-network Performance parameters and indices (YD/T1171-2001)

Step P02: a modeling language VSML (video Surveillance Model language) oriented to the design field of a video monitoring system is defined. The modeling language VSML needs to provide descriptive capabilities for the physical design of the video surveillance system and include attributes required to evaluate the model.

Because no simulation executable modeling language aiming at the field of video monitoring design exists at present, the VSML modeling language is provided constructively by expanding the configuration diagram in the UML 2.0. The main purpose of VSML is to provide a set of simple and easy-to-understand modeling symbols for easy operation, support designers to describe the system architecture at the hardware level, and meet the requirements of simulation operation. In the physical design topological structure of the video monitoring system, the most important is the association between the hardware node type and the node, and the simulation requirement is met. Fig. 3 is a schematic diagram of a VSML node meta-model, where VSML defines a physical node VSNode at first, which is used to represent a physical component in a video monitoring system, and mainly includes < < camera node > > (camera node), < < storage node > > (storage node), < < router node > > (router node), and all nodes possess semantic information such as nodeType (node type), brand (brand), price (price), and the like; then, other meta-models including Link, Agent, Application and the like are further defined, the Link is used for representing Link links between physical components and mainly includes semantic information such as linkType (Link type), capacity and the like. The Agent (Agent) and Application (Application) meta-models are defined for the purpose of emulating requirements. The Agent is used for representing a communication protocol Agent on a physical component of the video monitoring system, and semantic information such as an agentType (Agent type) and a packetSize (data packet size) is included; the Application mainly represents a data stream Application program on the agent, and includes semantic information such as agentType (agent type).

As shown in fig. 3, a conventional video surveillance system contains various types of hardware nodes, including: router node RouterNode, switch node SwitchNode, camera node CameraNode, television wall node TVwallNode, database node DbNode, VPN node VPNNode, storage node StorageNode, streaming media node streamnod, client node ClientNode, control node ControlNode.

Step P03: and designing and realizing a visual modeling tool of the video monitoring system. The tool is mainly used for assisting field designers to edit and design a physical topological model of a system and providing a model script file of simulation input. The objectives include: constructing a physical topological model of the system based on the VSML modeling language provided in the step two; the constructed physical topological model can be simulated and operated; and thirdly, hardware cost and function satisfiability statistics of the evaluation model in the step one can be completed.

The visual modeling tool shown in fig. 4 supports functions of adding nodes, editing node information, adding associations between nodes, and the like. The nodes are represented by corresponding graphic symbols, the editing node information is the attribute of the editing node, and the association between the adding nodes is to add connecting lines between the graphic symbols. Finally, the physical topology of the video monitoring system can be described by using the tool. The model constructed by the tool is required to describe the physical topology of the system clearly and easily; the created model may be interpreted as executing, i.e., capable of running in simulation.

Step P04: a designer of the video monitoring system utilizes a modeling tool to design a logically correct physical topology model of the video monitoring system according to user requirements including functional requirements, non-functional requirements, budget limitation and the like. The modeling tool provides different icons to represent different types of hardware, and a designer can simply and efficiently construct a physical topology model by only adding nodes represented by the icons, editing node information and completing links between the nodes.

Step P05: according to the designed physical topology model, the modeling tool can generate a corresponding OTCL script file. The OTCL language is used in NS2 as an interface language for emulating commands and configurations. The simulation evaluation object of the invention is a design scheme of a video monitoring system, and a visual modeling tool can only construct a physical topology model and cannot perform simulation operation, so that the simulation evaluation object needs to be converted into an OTCL script file and then serves as input information of the NS 2.

The process of generating the OTCL script file according to the physical topology model by utilizing the visual modeling tool comprises the following steps: firstly, traversing all VSML nodes in a physical topology model, counting and storing node types, node attribute information and links among the nodes to obtain related information, wherein the related information comprises four types of objects including a node array, a link array, a proxy array and an application array; and traversing the obtained four arrays, generating a corresponding OTCL statement and writing the OTCL statement into an OTCL script file.

OTCL is chosen because: on one hand, the OTCL can completely describe the designed model and can perform the related logic analysis; on the other hand, the simulation runtime tool cannot support direct model import, and needs to find an "intermediary", and the OTCL can support the NS2 simulation tool well.

Through traversing the generated OTCL script file, the price attributes of all nodes in the node array can be counted, and the sum is the hardware cost; and (3) counting node types and brand information of all nodes, and combining a function satisfiability hardware requirement table in a database (or a file) to obtain functions owned by the system design scheme.

Step P06: determining a simulation solution according to the requirement analysis of the simulation environment; the source code is modified and the NS2 is extended so that it supports the simulated execution of OTCL script files generated by the visualization modeling tool.

Although there are many options for current mainstream simulation software, including: OPNET, MATLAB, SPW, NS2, etc., but each has its limitations: OPNET and SPW are commercial software, the cost is high, and the MATLAB execution efficiency is low. The NS2 is a source opening software, and has high execution efficiency, flexible configuration and rich component library. Comprehensive analysis, NS2 is a better choice. Since the standard NS2 is unable to support the operations of inputting, reading, recognizing, etc. video stream data, the NS2 source code needs to be modified.

Fig. 5 is an extended schematic diagram of NS2, and the present invention mainly extends the relevant interfaces of the application layer and the transport layer of NS2, including three parts of video data reading, sending, transmitting and receiving. The application layer is the top layer in the NS2, located above the transport agent, and is primarily a traffic generator or simulation application. In the invention, the traffic generator is mainly concerned as a traffic generator of a traffic trace type, and the traffic is generated according to a tracking file. In order to receive video stream data, firstly, a traffic trace (traffic generator) needs to be extended, and an extension interface is myVSEF and is mainly used for reading video file information and transmitting frame data through a transmission layer. The transport layer in NS2 primarily implements proxies for various protocols, including TCP, UDP, and the like. In order to identify and read the data transmitted by the application layer, the layer obtains an extended interface myUDP by extending the NS2 element UDP, and records the information of the transmission time, identification and size of the data packet in the file set by the TCL script. In addition, in the transport layer, the Agent needs to be expanded to generate an interface myVSEF _ Sink for receiving the data packet transmitted through myUDP, and recording information such as receiving time and file size. The recorded information is used for evaluating the network performance.

Step P07: and taking the OTCL script file obtained in the step five and the external H.264/SVC video stream data as NS2 simulation input. The OTCL script file describes a physical topological model of a video monitoring system design scheme and is used for simulation construction of the video monitoring system in an NS2 simulation environment; video data adopts the mainstream h.264/SVC coding format. h.264/SVC is an extension of the h.264 standard, and is currently widely used in the field of video surveillance, and thus can be used to simulate video stream data transmitted in a video surveillance system.

Step P08: and after the input information is finished, carrying out simulation operation, and acquiring index data to be evaluated according to the index system structure of the evaluation model. After the OTCL script and the original video stream data are input, the video stream data transmission in the video monitoring system is simulated through a network environment simulated by NS2, the relevant process data is recorded, and finally the video stream data is output.

Fig. 6 is a schematic diagram of a simulation flow of the NS2, which completely describes a simulation operation process of the physical topology model, and includes the following specific steps: firstly, original video stream data is coded and converted into video stream with H.264/SVC format; correspondingly processing the converted H.264/SVC video stream to extract a video stream tracking file; the OTCL script file corresponding to the physical topological model designed by the modeling tool is input into NS2 simulation software and then is converted into an NS2 internal network simulation structure; and fourthly, the video stream tracking file is read and identified by the myVSEF, myUDP and other extension interfaces and is transmitted by the model of the video monitoring system simulated by the NS 2. In the process, the related information is recorded into a sending end tracking file and a receiving end tracking file; and fifthly, the video stream data flows out after running in the NS2 simulation environment, and is decoded by a decoder, reconstructed and repaired by video and other related processing to obtain the output video stream.

Step P09: after the simulation process is executed, acquiring data of the index to be evaluated according to the acquired simulation process data, and generating an evaluation result by referring to the parameters and the index range of the evaluation model.

According to the analysis in the step eight, it can be seen that the NS2 simulation tool can acquire data of the relevant reference index, and satisfies the evaluation model. An OTCL script file generated by a visual modeling tool according to a physical topology model designed by a designer is transmitted to an NS2 simulation tool, the simulation tool reads the script file, and an evaluation result of system cost and function satisfiability is obtained by analyzing the price and function attributes of each node in the file. In the simulation process, the data information recorded by the recorded sending end tracking file and the receiving end tracking file can be used for evaluating the network transmission performance. And finally, obtaining an evaluation result of the video transmission quality by comparing the original and output video stream parameter information. The specific results are analyzed as shown in Table 3.

TABLE 3 evaluation analysis of video surveillance system design results

Wherein comparing the input and output video stream data, the video transmission quality can be evaluated; the analysis of the OTCL script file can obtain the evaluation of the system cost and the function satisfiability; the network transmission performance can be analyzed and evaluated according to the data recorded by the tracking files of the sending terminal and the receiving terminal obtained in the process of the NS2 simulation.

The method is visual, simple and effective, a visual modeling tool is used for providing a convenient method for designers in the field of video monitoring systems to design the physical topological structure of the video monitoring system, and simulation verification is performed on the physical topological structure of the system according to the evaluation model of the video monitoring system provided by the invention to obtain attribute data to be evaluated, and the evaluation result which is more comprehensive and meets the requirements of users is obtained through analysis. The invention effectively avoids the risks in the design and deployment process of the traditional video monitoring system, and enables field designers to more efficiently and conveniently design a physical topology scheme and carry out multi-aspect evaluation and verification on the physical topology scheme.

Claims

1. An auxiliary design and evaluation method for a video monitoring system is characterized by comprising the following steps:

firstly, an evaluation model of a video monitoring system is constructed according to user requirements and industrial standards in the field of video monitoring;

the attributes inspected in the evaluation model comprise video transmission quality, network transmission performance, function satisfiability and system cost; each attribute is quantitatively evaluated by adopting a quantized index;

defining a modeling language VSML for the design of the video monitoring system; the modeling language VSML is obtained based on UML2.0 configuration diagram extension, faces the video monitoring field and is used for describing a physical topology model of a video monitoring system; the following node models are defined by using a modeling language VSML:

the system comprises a physical node VSNode used for representing a physical component in a video monitoring system;

a Link for representing a Link between the physical components;

the Agent is used for representing a communication protocol Agent on a physical component of the video monitoring system;

an Application for representing a data stream Application on an agent;

step three, realizing a visual modeling tool facing the field of the video monitoring system; the tool is used for editing and designing a physical topological model of the video monitoring system and generating a model script file of simulation input;

the visual modeling tool supports adding nodes, editing node information and adding association among the nodes; the nodes are represented by corresponding graphic symbols, the editing node information is the attribute of the editing node, and the association between the adding nodes is to add connecting lines between the graphic symbols;

designing a logical correct physical topology model of the video monitoring system by the designer of the video monitoring system according to the user requirements by using the visual modeling tool;

step five, generating a corresponding OTCL script file according to the physical topological model designed in the step four; the process of generating the OTCL script file is as follows: firstly, traversing all VSML nodes in a physical topology model, counting and storing node types, node attribute information and links among the nodes to obtain four types of objects of a node array, a link array, a proxy array and an application array; then, traversing the obtained four arrays, generating corresponding OTCL statements and writing the corresponding OTCL statements into an OTCL script file;

sixthly, selecting a simulation tool NS2, and expanding the NS 2;

in the application layer, the trafficTrace is expanded to obtain an expansion interface myVSEF used for reading video file information and transmitting frame data out through a transmission layer;

in a transmission layer, expanding the element UDP to obtain an expansion interface myUDP, which is used for recording the transmission time, identification and size information of the data packet in a file set by the TCL script;

on the transmission layer, the Agent is further expanded to obtain an expansion interface myVSEF _ Sink, which is used for receiving the data packet transmitted through the myUDP and recording the related information of the data packet, including the receiving time and the file size;

step seven, the OTCL script file and the external video stream data obtained in the step five are used as NS2 simulation input;

step eight, performing simulation by using the expanded NS2 simulation tool, recording simulation process data, and finally outputting video stream data; the process of executing the simulation includes:

converting original video stream data into video stream with H.264/SVC format; extracting a video stream tracking file;

after the OTCL script file is input into the NS2, the OTCL script file is converted into an NS2 internal network simulation structure;

the video stream tracking file is read and identified by the expansion interfaces myVSEF and myUDP, and is transmitted by a model of the video monitoring system simulated by the NS2 to obtain a sending end tracking file and a receiving end tracking file; the sending end tracking file and the receiving end tracking file are used for acquiring network transmission performance index data of the video monitoring system in the simulation environment;

the video stream data flows out after the simulation operation of the NS2, and the output video stream is obtained after the decoding, reconstruction and repair processing of a decoder;

counting an evaluation result according to the obtained simulation process data and an evaluation model;

(1) comparing the original video stream input into the NS2 with the output video stream of the NS2, and evaluating the video transmission quality, wherein the adopted quantization indexes comprise a mean subjective opinion score (MOS) and a peak signal-to-noise ratio (PSNR);

(4) and traversing the OTCL script file, counting the price attributes of all the nodes and evaluating the system cost.