Patent Publication Number: US-6910221-B1

Title: Moving image communication evaluation system and moving image communication evaluation method

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a moving image communication evaluation system and a moving image communication evaluation method and more particularly to a moving image communication evaluation system and a moving image communication evaluation method for evaluating a response time of moving image display to a moving image request in moving image distribution service on a network. 
   2. Description of the Related Art 
   In recent years, a moving image service industry of distributing moving images on a communication network has become prevalent. In the moving image service industry, the degree of satisfaction of the user requesting a moving image is important and the response time to the user&#39;s request is also one of the factors for determining the quality in the moving image service. Since moving image communication tends to take much time in processing of transmission, reception, decoding, display, etc., as compared with voice communication and data a communication, it is important to monitor and manage the response time to the user&#39;s request. 
   Hitherto, for example, a moving image communication evaluation system as described in JP-A-7-121459 and that as described in JP-A-5-336209 have been known as systems for measuring and evaluating the response time when a moving image is transmitted and received between communication terminals via a network. A configuration example of a moving image communication evaluation system in a related art shown in  FIG. 4  is provided by simplifying the configuration described in JP-A-7-121459, wherein a relay node  33  comprising a response time measurement section  6  and a relay node  34  comprising a response time measurement section  7  are connected to a network  10  and communication terminals  31  and  32  are connected to the relay nodes  33  and  34  respectively. 
   When a transmission request packet addressed to the communication terminal  32  is transmitted from the communication terminal  31  to the relay node  33 , the relay node  33  passes the transmission request packet to the network  10 . The communication terminal  32  receives the transmission request packet transmitted on the network  10  via the relay node  34  and transmits, for example, a reply packet addressed to the communication terminal  31  in response to the request in the transmission request packet. The reply packet is transmitted through the relay node  34 , the network  10 , and the relay node  33  and is received at the communication terminal  31 . 
   The response time measurement section  6  in the relay node  33  measures the difference between the time at which the relay node  33  passes the transmission request packet and the time at which the relay node  33  passes the reply packet as the response time. In contrast, if a transmission request packet addressed to the communication terminal  31  is transmitted from the communication terminal  32  and a reply packet addressed to the communication terminal  32  is transmitted from the communication terminal  31 , the response time measurement section  7  in the relay node  34  measures the difference between the time at which the relay node  34  passes the transmission request packet and the time at which the relay node  34  passes the reply packet as the response time. 
   A configuration example of a moving image communication evaluation system in a related art shown in  FIG. 5  is provided by simplifying the configuration described in JP-A-5-336209, wherein a communication terminal  35  comprising a response time measurement section  8  and a communication terminal  36  comprising a response time measurement section  9  are connected to a network  10 . When a transmission request packet is transmitted from the communication terminal  35  through the network  10  to the communication terminal  36 , the communication terminal  36  receives the transmission request packet and transmits, for example, a reply packet through the network  10  to the communication terminal  35  in response to the request in the transmission request packet. The communication terminal  35  receives the reply packet. 
   The response time measurement section  8  in the communication terminal  35  measures the difference between the time at which the communication terminal  35  transmits the transmission request packet and the time at which the communication terminal  35  receives the reply packet as the response time. In contrast, if a transmission request packet is transmitted from the communication terminal  36  to the communication terminal  35  and a reply packet is transmitted from the communication terminal  35  to the communication terminal  36 , the response time measurement section  9  in the communication terminal  36  measures the difference between the time at which the communication terminal  36  transmits the transmission request packet and the time at which the communication terminal  36  receives the reply packet as the response time. 
   However, if importance is placed on the degree of satisfaction of the user in the moving image service, the response time that the user feels, namely, the time interval between the instant at which the user performs operation of making a moving image request and the instant at which moving image display is changed as requested by the user must be measured, monitored, and managed. For example, in the moving image communication evaluation system in the related art as shown in  FIG. 4 , if a moving image transmission request packet is transmitted from the communication terminal  31 , only the time of “the packet traveling time between the relay node  33  connected to the communication terminal  31  and the communication terminal  32  transmitting the requested moving image” plus “the request processing time of the communication terminal  32  transmitting the requested moving image” is measured. In the moving image communication evaluation system in the related art as shown in  FIG. 5 , only the time of “the packet traveling time between the communication terminals” plus “the request processing time of the communication terminal transmitting the requested moving image” is measured. Thus, the moving image communication evaluation systems in the related arts cannot measure or evaluate the response time that the user feels. 
   Various types of communication networks become widespread; for example, the Internet, LANs (local area networks), public telephone networks, cable television networks, optical fiber networks, cellular mobile telephone networks, satellite communication networks, etc., can be used. Moreover, among the various communication networks, a heterogeneous network where different types of networks are interconnected is often used between communication terminals and a large number of types of communication protocols are actually used. Further, the types of networks to which terminals that can access one server are directly connected are various. Thus, the moving image communication evaluation system in the related art as shown in  FIG. 4  involves a large number of types of relay nodes  33  and  34  in which the response time measurement sections  6  and  7  are to be imbedded for which design, development, and evaluation must be carried out separately. 
   The communication networks are advancing rapidly and enlargement of a geographic area, change in network topology, improvement in, new installation of, and change in methods, systems, apparatus, protocols, terminals, and service, and the like are executed from day to day. Thus, in the moving image communication evaluation system in the related art as shown in  FIG. 4 , whenever the relay node  33 ,  34  is improved or newly installed, the response time measurement section  6 ,  7  must be improved or installed and evaluated accordingly. 
   Further, in the cellular mobile telephone networks, the satellite communication networks, the wireless LANs, etc., the geographical positions of the communication terminals change frequently and the radio transmission characteristics change in quality, namely, are good or bad from time to time, so that the transmission error occurrence frequency grows and in the Internet, packet discharge at heavy traffic hours occurs frequently, thus a moving image display error often occurs. A moving image communication evaluation system that can measure and evaluate the response time that the user feels if such a display screen error occurs is demanded. For the moving image service dealers and managers, the response time that the user feels is at stake and therefore a moving image server terminal does not require a response time measurement section. Thus, such a moving image communication evaluation system wherein only user terminals are provided each with a response time measurement section is demanded. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the invention to provide a moving image communication evaluation system that can measure and evaluate the response time that the user feels in response to the variety of networks, network chance, a transmission error, etc. 
   According to a first aspect of the present invention, there is provided a moving image communication evaluation system comprising:
         a moving image response time measurement unit being installed in a client communication terminal for transmitting a moving image request to a moving image server communication terminal connected to the client communication terminal via a network and receiving and displaying a moving image transmitted from the moving image server communication terminal in response to the moving image request, the moving image response time measurement unit for measuring the response time between the moving image request and moving image display state change; and   a moving image response time evaluation unit for receiving the response time transmitted from the moving image response time measurement unit through the network and evaluating the response time in the moving image communication between the moving image server communication terminal and the client communication terminal, characterized in that the moving image response time measurement unit comprises:   start point time measurement means for measuring the time at which the client communication terminal accepts the moving image request as start point time;   end point time measurement means for measuring the time at which a moving image display state is changed in accordance with the moving image request as end point time; and   response time calculation means for calculating the time between the start point time and the end point time as the response time, and that   the moving image response time evaluation unit receives the response time transmitted from the moving image response time measurement unit and evaluates the satisfaction degree of the user at the response time.       

   According to the first aspect of the present invention, in a moving image communication evaluation system comprising a moving image response time measurement unit being installed in a client communication terminal for transmitting a moving image request to a moving image server communication terminal connected to the client communication terminal via a network and receiving and displaying a moving image transmitted from the moving image server communication terminal in response to the moving image request, the moving image response time measurement unit for measuring the response time between the moving image request and moving image display state change, and a moving image response time evaluation unit for receiving the response time transmitted from the moving image response time measurement unit through the network and evaluating the response time in the moving image communication between the moving image server communication terminal and the client communication terminal, start point time measurement means contained in the moving image response time measurement unit measures the time at which the client communication terminal accepts the moving image request as start point time, end point time measurement means measures the time at which a moving image display state is changed in accordance with the moving image request as end point time, response time calculation means calculates the time between the start point time and the end point time as the response time, and the moving image response time evaluation unit receives the response time transmitted from the moving image response time measurement unit and evaluates the satisfaction degree of the user at the response time. 
   According to a second aspect of the present invention, in the moving image communication evaluation system, the moving image response time measurement unit further includes:
         moving image display anomaly detection means for detecting an anomaly of moving image display; and   duration measurement means for measuring the time during which the moving image display continues normally, wherein   if an anomaly is detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is less than a predetermined allowed time, the end point time measurement means determines the measured end point time invalid and if an anomaly is not detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is equal to or greater than the predetermined allowed time, the end point time measurement means determines the measured end point time valid and measures the end point time, and wherein   if an anomaly is detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is less than the predetermined allowed time, the start point time measurement means determines that the start point time measured just after it is invalid and if an anomaly is not detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is equal to or greater than the predetermined allowed time, the start point time measurement means determines that the start point time measured just after it is valid, and measures the start end time.       

   According to the second aspect of the present invention, in the moving image communication evaluation system, the moving image display anomaly detection means installed in the moving image response time measurement unit detects an anomaly of moving image display, the duration measurement means measures the time during which the moving image display continues normally, if an anomaly is detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is less than the predetermined allowed time, the end point time measurement means determines the measured end point time invalid and if an anomaly is not detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is equal to or greater than the predetermined allowed time, the end point time measurement means determines the measured end point time valid and measures the end point time, and if an anomaly is detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is less than the predetermined allowed time, the start point time measurement means determines that the start point time measured just after it is invalid and if an anomaly is not detected by the moving image display anomaly detection means and the duration measured by the duration measurement means is equal to or greater than the predetermined allowed time, the start point time measurement means determines that the start point time measured just after it is valid, and measures the start end time. 
   According to a third aspect of the present invention, the moving image communication evaluation system further includes:
         storage means for previously storing a time interval between the instant at which the moving image request is input to the client communication terminal and the instant at which the moving image request is accepted in the client communication terminal; and   start point time correction means for subtracting the time interval stored in the storage means from the start point time measured by the start point time measurement means, thereby correcting the start point time, wherein   the response time calculation means calculates the response time based on the start point time corrected by the start point time correction means.       

   According to the third aspect of the present invention, in the moving image communication evaluation system,
         the storage means previously stores a time interval between the instant at which the moving image request is input to the client communication terminal and the instant at which the moving image request is accepted in the client communication terminal, the start point time correction means subtracts the time interval stored in the storage means from the start point time measured by the start point time measurement means, thereby correcting the start point time, and the response time calculation means calculates the response time based on the start point time corrected by the start point time correction means.       

   According to a fourth aspect of the present invention, there is provided a moving image communication evaluation method for measuring the response time between a moving image request and moving image display state change in a client communication terminal for transmitting the moving image request to a moving image server communication terminal connected to the client communication terminal via a network and receiving and displaying a moving image transmitted from the moving image server communication terminal in response to the moving image request, then receiving the response time through the network and evaluating the response time in the moving image communication between the moving image server communication terminal and the client communication terminal, the moving image communication evaluation method comprising:
         the start point time measurement step of measuring the time at which the client communication terminal accepts the moving image request as start point time;   the end point time measurement step of measuring the time at which a moving image display state is changed in accordance with the moving image request as end point time;   the response time calculation step of calculating the time between the start point time and the end point time as the response time, thereby measuring the response time; and   the step of receiving the response time and evaluating the satisfaction degree of the user at the response time.       

   According to the fourth aspect of the present invention, in a moving image communication evaluation method for measuring the response time between a moving image request and moving image display state change in a client communication terminal for transmitting the moving image request to a moving image server communication terminal connected to the client communication terminal via a network and receiving and displaying a moving image transmitted from the moving image server communication terminal in response to the moving image request, then receiving the response time through the network and evaluating the response time in the moving image communication between the moving image server communication terminal and the client communication terminal, the start point time measurement step measures the time at which the client communication terminal accepts the moving image request as start point time, the end point time measurement step measures the time at which a moving image display state is changed in accordance with the moving image request as end point time, the response time calculation step calculates the time between the start point time and the end point time as the response time, thereby measuring the response time, and the evaluation step receives the response time and evaluates the satisfaction degree of the user at the response time. 
   Since the moving image response time measurement unit is installed in the client communication terminal, it is made possible to easily measure and evaluate the response time in the moving image communication in response to the variety of networks and the network change. Since the time between the moving image request and moving image display state change can be measured as the response time, the response time almost equal to the response time that the user feels can be measured and it is made possible to more accurately evaluate the satisfaction degree of the user at the response time. 
   According to a fifth aspect of the present invention, the moving image communication evaluation method further comprises:
         the moving image display anomaly detection step of detecting an anomaly of moving image display; and   the duration measurement step of measuring the time during which the moving image display continues normally, wherein   if an anomaly is detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is less than a predetermined allowed time, the end point time measurement step determines the measured end point time invalid and if an anomaly is not detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is equal to or greater than the predetermined allowed time, the end point time measurement step determines the measured end point time valid and measures the end point time, and wherein   if an anomaly is detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is less than the predetermined allowed time, the start point time measurement step determines that the start point time measured just after it is invalid and if an anomaly is not detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is equal to or greater than the predetermined allowed time, the start point time measurement step determines that the start point time measured just after it is valid, and measures the start end time.       

   According to the fifth aspect of the present invention, in the moving image communication evaluation method, the moving image display anomaly detection step detects an anomaly of moving image display, the duration measurement step measures the time during which the moving image display continues normally, if an anomaly is detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is less than a predetermined allowed time, the end point time measurement step determines the measured end point time invalid and if an anomaly is not detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is equal to or greater than the predetermined allowed time, the end point time measurement step determines the measured end point time valid and measures the end point time, and if an anomaly is detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is less than the predetermined allowed time, the start point time measurement step determines that the start point time measured just after it is invalid and if an anomaly is not detected by the moving image display anomaly detection step and the duration measured by the duration measurement step is equal to or greater than the predetermined allowed time, the start point time measurement step determines that the start point time measured just after it is valid, and measures the start end time. 
   Therefore, although the moving image display state is changed in response to the moving image request, if the moving image display stops in a short time because of a moving image display anomaly or a malfunction occurs and the user does not feel that the moving image display state is changed as requested, measurement of the response time is continued. If the moving image display state changed in response to a moving image request continues for the predetermined allowed time or longer from the time at which the moving image request is accepted or an anomaly does not occur, the time to the moving image display state change time is measured as the response time. Thus, even when a moving image display anomaly easily occurs in a communication environment, etc., wherein a transmission error and packet discard often occur, the response time that the user feels can be measured in response to the moving image display state change caused by an anomaly, and the satisfaction degree of the user at the response time can be evaluated. 
   According to a sixth aspect of the present invention, the moving image communication evaluation method further comprises:
         the storage step of previously storing a time interval between the instant at which the moving image request is input to the client communication terminal and the instant at which the moving image request is accepted in the client communication terminal; and   the start point time correction step of subtracting the time interval stored in the storage step from the start point time measured by the start point time measurement step, thereby correcting the start point time, wherein   the response time calculation step calculates the response time based on the start point time corrected by the start point time correction step.       

   According to the sixth aspect of the present invention, in the moving image communication evaluation method,
         the storage step previously stores a time interval between the instant at which the moving image request is input to the client communication terminal and the instant at which the moving image request is accepted in the client communication terminal, the start point time correction step subtracts the time interval stored in the storage step from the start point time measured by the start point time measurement step, thereby correcting the start point time, and the response time calculation step calculates the response time based on the start point time corrected by the start point time correction step.       

   Therefore, the time between the instant at which the moving image request is input to the client communication terminal and the instant at which the moving image display state is changed can be measured as the response time. Thus, the response time that the user feels can be measured more accurately and the satisfaction degree of the user at the response time can be evaluated more accurately. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram to show the general configuration of a moving image communication evaluation system  1  as one embodiment incorporating the invention; 
       FIG. 2  is a drawing to show a moving image communication state between communication terminals  20  and  30  in  FIG. 1 ; 
       FIG. 3  is a drawing to show a response time measurement state in the communication terminal  20  in  FIG. 1 ; 
       FIG. 4  is a block diagram to show a general system configuration example of a moving image communication evaluation system in a related art; and 
       FIG. 5  is a block diagram to show a general system configuration example of a moving image communication evaluation system in a related art. 
   

   DETAILED DESCRIPTION OF THE PRESENT INVENTION 
   Referring now to the accompanying drawings, there is shown an embodiment of the invention. 
     FIGS. 1  to  3  are drawings to show one embodiment of a moving image communication evaluation system incorporating the invention. 
   First, the configuration of the moving image communication evaluation system will be discussed. 
     FIG. 1  is a block diagram to show the general configuration of a moving image communication evaluation system  1  in the embodiment. In the figure, the moving image communication evaluation system  1  comprises a communication terminal  20  of a client, a communication terminal  30  of a moving image server, and an evaluation system  40 , which are connected to a network  10 . The client refers to a communication terminal of the user who accesses the moving image server through the network. 
   The network  10  is made up of, for example, the Internet, a LAN (local area network), a public telephone network, a cable television network, an optical fiber network, a cellular mobile telephone network, a satellite communication network, etc., for transmitting moving image request packets, response time data, moving image code, etc., transmitted and received among the communication terminals  20  and  30  and the evaluation system  40 . 
   The communication terminal  20  is a client communication terminal and is made up of a moving image request section  11 , a moving image display section  12 , a response time data buffer  13 , a moving image reception and decoding section  21 , a transmission section  22 , and a response time measurement section  50 . 
   An operation section  23  is connected to the moving image request section  11 . It comprises a keyboard having cursor keys, various function keys, etc., and a mouse and outputs a depress signal of the depressed key and a position signal of the mouse to the moving image request section  11 . The moving image request section  11  accepts the input signal from the operation section  23  as a moving image request, prepares a moving image request packet, and outputs the moving image request packet to the transmission section  22 . When the moving image request section  11  accepts the input signal from the operation section  23  as a moving image request, it outputs a request acceptance signal to a start point time measurement section  53  of the response time measurement section  50 . 
   The moving image refers to a digital moving image consisting of a sequence of instantaneous still image frames. Moving image display normally is to display frames one after another at a specific timing from the moving image start to predetermined end if operation is not performed or if a fault does not occur. Therefore, moving image display state change such as moving image display stop or disappearance from the screen from the display state of a moving image, return to normal-speed display from the fast-forward display state of a moving image, or restarting or starting of moving image display from the stop state of moving image display or the disappearance state from the screen always occurs because of some operation, control, or fault. The moving image request means a request for changing the moving image display state. The moving image requests include various requests for display start, end, temporarily halt, restart, rewinding, fast forward, locating the start, preview, etc., of a moving image and also include a listing request, a search request, an answer request, etc., to select a content desired by the user from among a large number of contents. 
   The transmission section  22  transmits the moving image request packet to the communication terminal  30  through the network  10 . The moving image request packet consists of a header section indicating the destination and the transmission source and a data section indicating the type of moving image request. The transmission section  22  transmits response time data input from the response time data buffer  13  to the evaluation system  40  through the network  10 . When acknowledging the transmission end, the transmission section  22  outputs a transmission acknowledge signal to the response time data buffer  13 . 
   The moving image reception and decoding section  21  receives moving image code transmitted through the network  10  from the communication terminal  30 , decodes the moving image code to image data, and outputs the resultant image data to the moving image display section  12 . 
   The moving image display section  12 , which comprises a CRT (cathode ray tube) or liquid crystal display screen or the like, displays an image based on the image data input from the moving image reception and decoding section  21  and outputs a moving image display state flag to an end point time measurement section  54 , a moving image display anomaly detection section  55 , and a moving image display duration measurement section  56  of the response time measurement section  50 . The moving image display state flag is a digital signal or data for identifying a moving image display state such as a disappearance state of moving image display from the screen, a stop state of moving image display (still image display state), a normal-speed moving image display state, a fast-forward moving image display state, a rewound moving image display state, a moving image start location display state, or a moving image preview display state. 
   The response time measurement section  50  (corresponding to moving image response time measurement unit as claimed in claims  1  and  2 ) consists of a response time calculation section  52 , the above-mentioned start point time measurement section  53 , the above-mentioned end point time measurement section  54 , the above-mentioned moving image display anomaly detection section  55 , the above-mentioned moving image display duration measurement section  56 , an allowed time comparison section  57 , an end point time determination section  58 , and a start point time determination section  59  for measuring the response time, namely, the time interval between the instant at which a moving image request is entered through the operation section  23  and the instant at which moving image display state change is started. 
   The end point time measurement section  54  recognizes moving image display state change according to change in the moving image display state flag input from the moving image display section  12 , measures the change time in the moving image display state by a clock section (not shown), and outputs the measured time to the end point-time determination section  58  as the end point time. The clock section may be installed in the communication terminal  20  or may be connected externally. 
   The moving image display anomaly detection section  55  detects an abnormal moving image display state caused by moving image display stop, display erasure, operation failure, or malfunction occurring because of an anomaly in the moving image reception and decoding section  21  or the moving image display section  12  and outputs a moving image display anomaly signal to the moving image display duration measurement section  56 , the end point time determination section  58 , and the start point time determination section  59  at the detection time. 
   For example, an overflow of a reception buffer, decoding-impossible code detection of a decoder, an overflow and an underflow of a decoder buffer, and loss of a comparatively large amount of moving image code in the moving image reception and decoding section  21  and an unrecoverable display timing anomaly and detection of display-impossible decoder output in the moving image display section  12 , and the like can be named as the moving image display anomaly causes. The anomalies and faults are caused by a transmission error, packet discard, a packet reception timing anomaly, etc., at the moving image code reception time and easily occur particularly in radio communication in a poor state of transmission characteristics, a busy packet multiplex network, etc. 
   The moving image display duration measurement section  56  (corresponding to duration measurement means as claimed in claim  1  and duration measurement step as claimed in claim  3 ) recognizes moving image display state change according to change in the moving image display state flag input from the moving image display section  12 , measures the change time in the moving image display state by the clock section (not shown), stores the time, and starts to measure the duration. If a moving image display anomaly signal is not input from the moving image display anomaly detection section  55 , the moving image display duration measurement section  56  measures the time to recognizing of moving image display state change according to another change in the moving image display state flag input from the moving image display section  12  as the duration; if a moving image display anomaly signal is input from the moving image display anomaly detection section  55 , the moving image display duration measurement section  56  measures the time to input of the moving image display anomaly signal as the duration and outputs the duration to the allowed time comparison section  57 . 
   The allowed time comparison section  57  has a predetermined setup allowed time and compares the duration input from the moving image display duration measurement section  56  with the setup allowed time. If the duration is less than the allowed time or is equal to or greater than the allowed time, the allowed time comparison section  57  outputs the comparison result to the end point time determination section  58  and the start point time determination section  59 . 
   If the comparison result indicating that the duration is equal to or greater than the allowed time is input from the allowed time comparison section  57 , the end point time determination section  58  determines that the end point time input from the end point time measurement section  54  just before the comparison result is input is valid, and outputs the end point time to the response time calculation section  52 . If the comparison result indicating that the duration is less than the allowed time is input from the allowed time comparison section  57  and a moving image display anomaly signal is input from the moving image display anomaly detection section  55 , the end point time determination section  58  determines that the end point time input from the end point time measurement section  54  just before the comparison result is input is invalid, and does not outputs the end point time to the response time calculation section  52 . If a moving image display anomaly signal is not input from the moving image display anomaly detection section  55  although the comparison result indicating that the duration is less than the allowed time is input from the allowed time comparison section  57 , the end point time determination section  58  determines that the end point time input from the end point time measurement section  54  just before the comparison result is input is valid, and outputs the end point time to the response time calculation section  52 . That is, even if the moving image display state duration is less than the allowed time, if the change in the moving image state at the time is not caused by an anomaly and is normal moving image state change responsive to a moving image request entered through the operation section  23 , the end point time determination section  58  determines that the moving image display start time is valid as the end point time, and outputs the time to the response time calculation section  52 . 
   The start point time measurement section  53  inputs a request acceptance signal from the moving image request section  11 , measures the time at which the request acceptance signal is input by the clock section (not shown), previously stores the time between the instant at which the moving image request is entered through the operation section  23  and the instant at which the request acceptance signal is input to the start point time measurement section  53 , and outputs the time found by subtracting the previously stored time from the time at which the request acceptance signal is input, measured by the clock section to the start point time determination section  59  as the start point time. 
   If the comparison result indicating that the duration is less than the allowed time is input from the allowed time comparison section  57  and a moving image display anomaly signal is input from the moving image display anomaly detection section  55 , the start point time determination section  59  determines that the start point time input from the start point time measurement section  53  just after the input is invalid, and does not output the start point time to the response time calculation section  52 . If the comparison result indicating that the duration is equal to or greater than the allowed time is input from the allowed time comparison section  57  or if a moving image display anomaly signal is not input from the moving image display anomaly detection section  55  although the comparison result indicating that the duration is equal to or greater than the allowed time is input from the allowed time comparison section  57 , the start point time determination section  59  determines that the start point time input from the start point time measurement section  53  just after the input is valid, and outputs the start point time to the response time calculation section  52 . 
   The response time calculation section  52  calculates the difference between the start point time input from the start point time determination section  59  and the end point time input from the end point time determination section  58  as the response time and outputs the response time to the response time data buffer  13 . 
   As the response time is input from the response time calculation section  52  in the response time measurement section  50 , the response time data buffer  13  stores the response time in order as response time data and outputs the response time data to the transmission section  22 . When a transmission acknowledge signal is input from the transmission section  22 , the response time data buffer  13  erases the response time data whose transmission is acknowledged by the transmission acknowledge signal. 
   The communication terminal  30  is a moving image server communication terminal. Upon reception of a moving image request packet transmitted through the network  10  from the communication terminal  20 , the communication terminal  30  identifies the type of moving image request contained in the moving image request packet, codes image data in response to the identified moving image request type to prepare moving image code, and transmits the moving image code to the communication terminal  20 . 
   The evaluation system  40  (corresponding to moving image response time evaluation unit) receives the response time data transmitted from the transmission section  22  in the communication terminal  20 , monitors and manages the response time in the moving image service that the user of the communication terminal  20  feels, and evaluates the satisfaction degree of the user at the response time. 
   Next, the operation of the described moving image communication evaluation system is as follows: 
     FIG. 2  is a drawing to show a moving image display processing procedure in the described moving image communication evaluation system  1 . As shown here, when a user&#39;s moving image request  80  is entered through the operation section  23  of the communication terminal  20 , moving image request acceptance  75  at the moving image request section  11 , moving image request transmission and reception  76  between the communication terminals  20  and  30 , preparation for a moving image  77  of coding moving image data into moving image code, etc., in the communication terminal  30 , moving image transmission and reception  78  between the communication terminals  30  and  20 , and moving image decoding  79  by the moving image reception and decoding section  21  are executed, and moving image display  88  responsive to the user&#39;s request is started by the moving image display section  12 . 
   The start point time measurement section  53  measures the time at which the moving image request acceptance  75  is executed and measures the time found by subtracting the time taken from the user&#39;s moving image request  80  to the moving image request acceptance  75  as start point time  91 . The end point time measurement section  54  measures the time at which the moving image display  88  is started as end point time  92 . The response time calculation section  52  measures the time between the start point time  91  and the end point time  92  as response time  90 . 
   Next, if moving image display contains an anomaly, the operation of the moving image communication evaluation system is as follows: 
     FIG. 3  is a drawing to show a response time measuring procedure in the moving image communication evaluation system  1  if moving image display contains an anomaly. 
   For example, if the user enters user&#39;s moving image request  80  for making a request for starting moving image display through the operation section  23 , the moving image request is accepted by the moving image request section  11  and a request acceptance signal is input to the start point time measurement section  53 , which then measures the time at which the request acceptance signal is input. The measured time at which the request acceptance signal is input is detection time  95 . The start point time measurement section  53  previously stores the time between the instant at which the moving image request is entered through the operation section  23  and the instant at which the request acceptance signal is input to the start point time measurement section  53 , and subtracts the stored time from the detection time  95  for making a correction, then measures start point time  91 . 
   When the moving image request is accepted by the moving image request section  11 , the steps of the moving image request transmission and reception  76  to the moving image decoding  79  shown in  FIG. 2  are executed and moving image display  86  is started by the moving image display section  12 . At this time, for example, if the moving image display abnormally stops in a short time since the start of the moving image display  86  because of an anomaly such as a radio transmission error, the moving image display anomaly detection section  55  outputs a moving image display anomaly signal to the moving image display duration measurement section  56 , the end point time determination section  58 , and the start point time determination section  59 . The moving image display duration measurement section  56  outputs a short duration to the allowed time comparison section  57 . The allowed time comparison section  57  outputs the comparison result indicating that the duration is less than the allowed time to the end point time determination section  58  and the start point time determination section  59 . Thus, the end point time determination section  58  determines that the start time of the moving image display  86  is invalid as the end point time from the moving image display anomaly signal and the comparison result indicating that the duration is less than the allowed time. 
   The user&#39;s moving image start request is not met. Then, when the user again makes a user&#39;s moving image request  81  through the operation section  23 , the start point time determination section  59 , to which the moving image display anomaly signal is input from the moving image display anomaly detection section  55  and the comparison result indicating that the duration is less than the allowed time is input from the allowed time comparison section  57 , determines that the start point time concerning the user&#39;s moving image request  81  input from the start point time measurement section  53  just after they are input is invalid. 
   In response to the user&#39;s moving image request  81 , the steps of the moving image request acceptance  75  to the moving image decoding  79  shown in  FIG. 2  are again executed and moving image display  87  is started. After this, if the moving image display again abnormally stops in a short time because of a radio transmission error, etc., the end point time determination section  58  determines that the start time of the moving image display  87  is invalid as the end point time like the start time of the moving image display  86 . 
   Since the user&#39;s moving image start request is not met, the user further makes a user&#39;s moving image request  82  through the operation section  23 . Also in this case, the start point time determination section  59 , to which the moving image display anomaly signal is input from the moving image display anomaly detection section  55  and the comparison result indicating that the duration is less than the allowed time is input from the allowed time comparison section  57 , determines that the start point time concerning the user&#39;s moving image request  82  input from the start point time measurement section  53  just after they are input is invalid. 
   In response to the user&#39;s moving image request  82 , the steps of the moving image request acceptance  75  to the moving image decoding  79  shown in  FIG. 2  are again executed and moving image display  88  is started. At this time, if the radio transmission is recovered from the error and the moving image display duration measurement section  56  measures duration equal to or greater than the allowed time and outputs the duration to the allowed time comparison section  57 , the allowed time comparison section  57  outputs the comparison result indicating that the duration is equal to or greater than the allowed time to the end point time determination section  58  and the start point time determination section  59 . The end point time determination section  58  outputs the end point time  92  input from the end point time measurement section  54  just before the comparison result is input to the end point time determination section  58  to the response time calculation section  52 . 
   The response time calculation section  52  calculates the difference between the start point time  91  almost equal to the time at which the user operates the operation section  23  and the end point time  92  at which the moving image display is normally started to find the response time  90  and outputs the response time data to the response time data buffer  13 , then the response time data is transmitted from the transmission section  22  through the network  10  to the evaluation system  40 . Thus, if an anomaly occurs in the moving image display, the response time that the user feels, namely, the time between the instant at which the user performs operation of making a moving image request and the instant at which moving image display is normally started can be measured and evaluated in response to the moving image display anomaly. 
   Thus, when a moving image request is entered through the operation section  23 , the moving image request section  11  accepts the moving image request and the transmission section  22  transmits the moving image request through the network  10  to the communication terminal  30 . On the other hand, the start point time measurement section  53  measures the time at which the moving image request is entered through the operation section  23  as the start point time, and the start point time determination section  59  determines whether the time is valid or invalid as the start point time. If the comparison result input from the allowed time comparison section  57  indicates that the duration is less than the allowed time and a moving image display anomaly signal is input from the moving image display anomaly detection section  55 , the start point time just after they are input is determined invalid; if the comparison result indicating that the duration is equal to or greater than the allowed time is input from the allowed time comparison section  57  and a moving image display anomaly signal is not input from the moving image display anomaly detection section  55 , the start point time just after the input is determined valid and is output to the response time calculation section  52 . 
   When moving image code is transmitted from the communication terminal  30  through the network  10 , the moving image reception and decoding section  21  receives the moving image code and decodes the code to image data, and the moving image display section  12  executes moving image display. The end point time measurement section  54  measures the time at which the moving image display is started, the moving image display duration measurement section  56  measures the duration of the moving image display, and the allowed time comparison section  57  compares the duration with the preset allowed time. The end point time determination section  58  determines whether the end point time measured by the end point time measurement section  54  is valid or invalid according to the comparison result of the allowed time comparison section  57 . If the comparison result indicating that the duration is less than the allowed time is input from the allowed time comparison section  57  and a moving image display anomaly signal is input from the moving image display anomaly detection section  55 , the end point time determination section  58  determines the end point time invalid; if a moving image display anomaly signal is not input from the moving image display anomaly detection section  55  and the comparison result indicating that the duration is equal to or greater than the allowed time is input from the allowed time comparison section  57 , the end point time determination section  58  determines the end point time valid and outputs the end point time to the response time calculation section  52 . 
   The response time calculation section  52  calculates the difference between the start point time and the end point time as the response time and outputs the response time to the response time data buffer  13 , then the response time is transmitted from the transmission section  22  through the network  10  to the evaluation system  40 . The evaluation system  40  receives the response time data and evaluates the satisfaction degree of the user at the response time and the like, thereby monitoring and managing the response time in the moving image service. 
   Therefore, even when a moving image display anomaly easily occurs in a communication environment wherein a transmission error and packet discard often occur, such as radio communication or the Internet, it is made possible to measure and evaluate the response time that the user feels, namely, the time between the instant at which the user performs operation of making a moving image request and the instant at which the user feels chat moving image display is changed exactly as the moving image request. 
   Since relay nodes, etc., are not required and the communication terminal  30  of the server terminal need not be provided with any response time measurement section, the moving image communication evaluation system can cover various network types; if network change frequently occurs, the response time measurement section  50  need not be improved or again evaluated each time and it is made possible to measure and evaluate the response time that the user feels in response to the variety of networks and the network change. 
   In the embodiment, each moving image request accepted by the moving image request section  11  is transmitted as a moving image request packet from the transmission section  22  through the network  10  to the communication terminal  30 , but the scope of the invention is not limited to the form. For example, the communication terminal  20  may further include a moving image request processing section, etc., and it may be made possible to process a moving image request and change the moving image display state in the communication terminal  20  depending on the type of moving image request; the composition and arrangement of parts may be resorted to without departing from the spirit and scope of the invention. 
   According to the present invention, since the moving image response time measurement unit is installed in the client communication terminal, it is made possible to easily measure and evaluate the response time in the moving image communication in response to the variety of networks and the network change. Since the time between the moving image request and moving image display state change can be measured as the response time, the response time almost equal to the response time that the user feels can be measured and it is made possible to more accurately evaluate the satisfaction degree of the user at the response time. 
   According to the present invention, although the moving image display state is changed in response to the moving image request, if the moving image display stops in a short time because of a moving image display anomaly or a malfunction occurs and the user does not feel that the moving image display state is changed as requested, measurement of the response time is continued. If the moving image display state changed in response to a moving image request continues for the predetermined allowed time or longer from the time at which the moving image request is accepted or an anomaly does not occur, the time to the moving image display state change time is measured as the response time. Thus, even when a moving image display anomaly easily occurs in a communication environment, etc., wherein a transmission error and packet discard often occur, the response time that the user feels can be measured in response to the moving image display state change caused by an anomaly, and the satisfaction degree of the user at the response time can be evaluated. 
   According to the present invention, the time between the instant at which the moving image request is input to the client communication terminal and the instant at which the moving image display state is changed can be measured as the response time. Thus, the response time that the user feels can be measured more accurately and the satisfaction degree of the user at the response time can be evaluated more accurately.