JP5136530B2 - Communication terminal device, terminal control method, and terminal control program - Google Patents

Description

  The present invention relates to a communication terminal device, a terminal control method, and a terminal control program that can reduce a load on a network.

    Conventionally, a data processing apparatus for encoding an image is known. For example, in the data processing apparatus described in Patent Document 1, the magnification of the photographing speed of the photographing device with respect to the frame rate of the display device is recognized as the photographing speed magnification. The recognized photographing speed magnification is set as an M value representing the picture interval. Then, the data processing device encodes the image data input from the photographing device based on the M value, and generates display data having an I picture, a P picture, and a B picture. Then, when the photographing speed of the photographing device and the frame rate of the display device are different, by outputting a picture with the frame rate and timing of the display device to the display device, the input from the photographing device and the display device Is synchronized with the display.

JP 2007-221535 A

  The data processing apparatus described in Patent Document 1 is specialized in obtaining synchronization between one input and one output. For this reason, even when there are a plurality of inputs, it is possible to synchronize with respect to one input. For example, when sending encoded data to the network, the load on the network can be reduced to some extent. However, the data processing apparatus described in Patent Document 1 cannot set an appropriate synchronization timing in consideration of a plurality of inputs. For this reason, there has been a problem that an image cannot be encoded so that the load on the network can be appropriately reduced.

  The present invention has been made to solve the above-described problems, and is a communication terminal device, a terminal control method, and a terminal control program capable of encoding an image so as to appropriately reduce the load on the network. The purpose is to provide.

In order to achieve the above object, the communication terminal device according to claim 1 is connected to a network, encodes an image input by an image input unit, and encodes information that is information obtained by encoding the image. A communication terminal device that transmits and receives to / from a connection terminal that is another terminal connected via the network, and that obtains a first frame rate that is a frame rate of the connection terminal connected to the network A period for encoding the image as an I picture based on a rate acquisition unit, the first frame rate acquired by the frame rate acquisition unit, and a second frame rate which is a frame rate of the communication terminal device; An encoding period determining means for determining an I picture encoding period; and the I determined by the encoding period determining means A first code which is information obtained by encoding the image on the basis of the I-picture encoding period determined by the encoding period determining means and an encoding period transmitting means for transmitting a cut-out encoding period to the connected terminal; First encoding means for generating encoded information, and encoded information storage means for storing the first encoded information generated by the first encoding means in a first storage device that is an apparatus for storing data It is provided with.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, the encoding period determining unit includes the first frame rate acquired by the frame rate acquiring unit and the first frame rate. Display time calculating means for calculating, for each of the connection terminal and the communication terminal device, an image display time which is a time for displaying one image on the image display means for displaying an image from the second frame rate; One of at least two common multiples of the image display time among the image display time of the connection terminal and the image display time of the communication terminal device calculated by the display time calculation means is the I The image processing apparatus is further provided with first period determining means for setting a picture encoding period.

In addition to the configuration of the invention according to claim 2, the communication terminal device according to claim 3 is characterized in that the coding period determining means is the image of the connection terminal calculated by the display time calculating means. First calculation means for calculating a first least common multiple which is a time of a least common multiple of the image display time of at least two of the display time and the image display time of the communication terminal device;
First determination means for determining whether or not the first least common multiple calculated by the first calculation means is equal to or less than a first threshold; and the first least common multiple is determined by the first determination means to be the first threshold. An image obtained by changing at least one of the image display times of the image display time of the connection terminal and the image display time of the communication terminal device calculated by the display time calculation unit when it is determined that the image display time is not less than A change for calculating the changed image display time so that a second least common multiple which is a least common multiple of the changed image display time which is a display time and the image display time other than the changed image display time is equal to or less than the first threshold value. Further comprising: time calculation means; and second period determination means that uses the second least common multiple as the I picture encoding period, wherein the communication terminal apparatus uses the change time calculation means. A frame rate for instructing the connection terminal or the communication terminal device whose image display time has been changed to the changed image display time so that the image display time becomes the changed image display time. A first frame for changing the first frame rate of the communication terminal apparatus when the communication terminal apparatus is instructed to change the first frame rate by the change instruction means and the frame rate change instruction means; And a rate changing means.

  In addition to the configuration of the invention according to any one of claims 1 to 3, the communication terminal device according to claim 4 includes an encoding cycle acquisition unit that acquires the I picture encoding cycle of the connection terminal. Second determination for determining whether or not the I picture encoding period of the connected terminal acquired by the encoding period acquisition means matches the I picture encoding period determined by the encoding period determination means And the second judging means do not match the I picture coding period of the connected terminal obtained by the coding period obtaining means with the I picture coding period determined by the coding period determining means The I picture determined by the encoding period determining means is transmitted to the connection terminal determined that the I picture encoding periods do not match. Characterized by comprising second coding cycle transmitting means and further to retransmit No. of cycles.

  According to a fifth aspect of the present invention, there is provided a communication terminal apparatus according to the I picture coding cycle transmitted by the coding cycle transmission means in addition to the configuration of the invention according to any one of the first to fourth aspects. The encoded information storage means further includes encoded information receiving means for receiving second encoded information that is encoded information transmitted from the connected terminal and transmitted from the connected terminal, and the encoded information storage means includes the first code The first encoded information created by the encoding means and the second encoded information received by the encoded information receiving means are stored in the first storage device.

  Further, in addition to the configuration of the invention according to any one of claims 1 to 4, the communication terminal device according to claim 6 is configured such that the encoded information storage unit performs the first operation in response to a request from the connection terminal. Selecting I picture coding information, which is information of the image coded as the I picture based on the I picture coding period, from the first coding information stored in one storage device; The information processing apparatus further includes encoding information transmission means for transmitting the encoding information to the connection terminal.

  According to a seventh aspect of the present invention, in addition to the configuration of the fifth aspect of the invention, the communication terminal device stores the first information storage device by the encoded information storage unit in response to a request from the connection terminal. From the first encoded information and the second encoded information, select I picture encoded information that is information of the image encoded as the I picture based on the I picture encoding period, It further comprises encoded information transmitting means for transmitting the I picture encoded information to the connected terminal.

  Further, in addition to the configuration of the invention according to claim 5 or 7, the communication terminal device according to claim 8 is transmitted by the encoding cycle transmission means of another communication terminal device connected to the network. Coding cycle receiving means for receiving the I picture coding cycle, and second coding means for creating the second coding information based on the I picture coding cycle received by the coding cycle receiving means And encoded information transmitting means for transmitting the second encoded information created by the second encoding means to the other communication terminal device.

  The terminal control method according to claim 9 is connected to a network, encodes an image input by image input means, and connects encoded information, which is information obtained by encoding the image, via the network. A terminal control method executed in a communication terminal device that transmits and receives to / from a connected terminal that is another terminal, and obtains a first frame rate that is a frame rate of the connected terminal connected to the network Based on a frame rate acquisition step, the first frame rate acquired by the frame rate acquisition step, and a second frame rate, which is a frame rate of the communication terminal device, in a cycle for encoding the image as an I picture A coding cycle determining step for determining a certain I picture coding cycle; and the coding cycle determining step. The image is encoded based on the encoding period transmission step of transmitting the I picture encoding period determined by the transmission terminal to the connecting terminal and the I picture encoding period determined by the encoding period determination step. A first encoding step for generating first encoded information that is information, and the first encoded information generated by the first encoding means are stored in a first storage device that is a device for storing data And an encoded information storage step.

  The terminal control program according to claim 10 is connected to a network, encodes an image input by an image input means, and connects encoded information, which is information obtained by encoding the image, via the network. A terminal control program that is executed in a communication terminal device that transmits and receives to / from a connected terminal that is another terminal, the first frame rate being a frame rate of the connected terminal connected to the network The image is encoded as an I picture based on the frame rate acquisition step for acquiring the frame rate, the first frame rate acquired in the frame rate acquisition step and the second frame rate which is the frame rate of the communication terminal device Encoding period determining step for determining the I picture encoding period, And a coding cycle transmission step for transmitting the I picture coding cycle determined by the coding cycle determination step to the connection terminal, and the I picture coding cycle determined by the coding cycle determination step. A first encoding step for generating first encoded information, which is information obtained by encoding the image, and the first encoded information generated by the first encoding means in an apparatus for storing data. An encoded information storing step for storing in a certain first storage device is executed.

  The communication terminal apparatus according to the first aspect of the present invention determines an I picture encoding period so that an image can be encoded based on a common I picture encoding period between the communication terminal apparatus and the connection terminal. Then, by encoding an image based on this I picture encoding cycle, it is possible to synchronize the timing at which the communication terminal apparatus and the connecting terminal encode an image as an I picture. If the timing for encoding an image as an I picture is synchronized, for example, when the encoded image is decoded at the connected terminal and played back by fast forward, rewind, or cue, the reference picture is not transmitted. By transmitting only the I picture to the connected terminal via the network, it is possible to appropriately reduce the load on the network. That is, the communication terminal device can create and store the first encoded information so that the load on the network can be appropriately reduced.

  In the communication terminal device according to the second aspect of the present invention, one of the times of a common multiple of at least two image display times can be set as the I picture encoding cycle. Therefore, in addition to the effect of the invention according to claim 1, the I picture encoding period is determined without changing at least two frame rates of the first frame rate of the connecting terminal and the second frame rate of the communication terminal device. can do.

  According to the communication terminal apparatus of the invention according to claim 3, the I picture encoding cycle is set to be equal to or less than the first threshold value. Therefore, in addition to the effect of the invention described in claim 2, the I picture encoding cycle can be set at an appropriate cycle.

  According to the communication terminal apparatus of the invention as claimed in claim 4, it is determined whether or not the I picture coding period of the connecting terminal coincides with the I picture coding period determined by the coding period determining means. If not, since the I picture encoding period determined by the encoding period determining means is retransmitted to the connecting terminal, in addition to the effect of the invention according to any one of claims 1 to 3, the connection can be made more reliably. It is possible to make the I picture encoding period of the terminal coincide with the I picture encoding period determined by the encoding period determining means.

  Since the communication terminal device of the invention according to claim 5 can receive the second encoded information encoded by the connection terminal and store it in the first storage device, the communication terminal device according to any one of claims 1 to 4 In addition to the effect of the invention, the communication terminal device can store the first encoded information and the second encoded information in the first storage device.

According to the communication terminal device of the invention according to claim 6, in response to a request from the connection terminal, the I picture encoded information is selected from the first encoded information stored in the first storage device, Can be sent to the connected terminal. For this reason, in addition to the effect of the invention according to any one of claims 1 to 4, appropriate I picture coding information can be transmitted in response to a request from the connecting terminal.

  According to the communication terminal device of the invention according to claim 7, in response to a request from the connection terminal, from the first encoded information and the second encoded information stored in the first storage device, an I picture Encoding information can be selected and transmitted to the connected terminal. For this reason, in addition to the effect of the invention described in claim 5, appropriate I picture encoding information can be transmitted in response to a request from the connecting terminal.

  The communication terminal apparatus according to the eighth aspect of the invention can also operate as a connection terminal. Therefore, in addition to the effect of the invention according to claim 5 or 7, based on the I picture encoding period determined by the encoding period determining means of another communication terminal device, operating as a connection terminal, Second encoded information can be created.

  In the terminal control method according to the ninth aspect of the present invention, the I picture coding cycle is determined so that the image can be coded based on the common I picture coding cycle between the communication terminal device and the connection terminal. Then, by encoding an image based on this I picture encoding cycle, it is possible to synchronize the timing at which the communication terminal apparatus and the connecting terminal encode an image as an I picture. If the timing for encoding an image as an I picture is synchronized, for example, when the encoded image is decoded at the connected terminal and played back by fast forward, rewind, or cue, the reference picture is not transmitted. By transmitting only the I picture to the connected terminal via the network, it is possible to appropriately reduce the load on the network. That is, the communication terminal device can create and store the first encoded information so that the load on the network can be appropriately reduced.

  A terminal control program according to a tenth aspect of the present invention causes a computer to determine an I picture encoding period so that an image can be encoded based on a common I picture encoding period between a communication terminal device and a connection terminal. Then, by encoding an image based on this I picture encoding cycle, it is possible to synchronize the timing at which the communication terminal apparatus and the connecting terminal encode an image as an I picture. If the timing for encoding an image as an I picture is synchronized, for example, when the encoded image is decoded at the connected terminal and played back by fast forward, rewind, or cue, the reference picture is not transmitted. By transmitting only the I picture to the connected terminal via the network, it is possible to appropriately reduce the load on the network. That is, the communication terminal device can create and store the first encoded information so that the load on the network can be appropriately reduced.

1 is a block diagram showing a configuration of a video conference system 1. FIG. 3 is a block diagram showing an electrical configuration of a communication terminal device 3. FIG. 2 is a conceptual diagram showing each storage area of an HDD 31. FIG. 3 is a conceptual diagram showing each storage area of a RAM 22. FIG. It is the schematic diagram which showed the timing which the communication terminal device 3 and the connection terminals 4 and 5 in the case of a 1st example encode a picture, and produce | generate a picture. It is a flowchart which shows the 1st main process by CPU20. It is a flowchart which shows the encoding period determination process by CPU20. It is a flowchart which shows the image display time change process by CPU20. It is the schematic diagram which showed the timing which the communication terminal device 3 and the connection terminals 4 and 5 in the case of a 2nd example encode a picture, and produce | generate a picture. It is a flowchart which shows the 1st confirmation process by CPU20. It is a flowchart which shows the video recording process by CPU20. It is the schematic which showed the timing which the communication terminal device 3 and the connection terminals 4 and 5 in the case of a 1st example encode a picture based on an I picture encoding period, and produce | generate a picture. It is the schematic which showed the timing which the communication terminal device 3 and the connection terminals 4 and 5 in the case of a 2nd example encode a picture based on an I picture encoding period, and produce | generate a picture. It is a flowchart which shows the 2nd main process by CPU20. It is a flowchart which shows the 2nd confirmation process by CPU20. It is a block diagram which shows the structure of the video conference system 1 in the state in which the connection terminal 6 was connected to the network 2 in the middle of the video conference. It is a flowchart which shows the 3rd main process by CPU20. It is a flowchart which shows the 4th main process by CPU20. It is a block diagram which shows the structure of the video conference system 1 in case the external storage device 7 is provided.

  Hereinafter, a communication terminal device 3 embodying a communication terminal device according to the present invention will be described with reference to the drawings. These drawings are used for explaining the technical features that can be adopted by the present invention, and the configuration of the communication terminal apparatus and the flowcharts of various processes described are intended to be limited thereto. Instead, it is just an illustrative example.

  First, the configuration of the video conference system 1 including the communication terminal device 3 as a component will be described with reference to FIG. The video conference system 1 includes a network 2, a communication terminal device 3, a connection terminal 4, and a connection terminal 5. The communication terminal device 3 and the connection terminals 4 and 5 are connected to each other via the network 2. In this video conference system 1, a video conference is carried out by transmitting and receiving images and sounds between the communication terminal device 3, the connection terminal 4 and the connection terminal 5 via the network 2. In FIG. 1, three units of the communication terminal device 3, the connection terminal 4, and the connection terminal 5 are connected to the network 2, but the number is not limited, and for example, 10 units may be connected to the network 2. Good. In the following description, when one of the communication terminal device 3 connected to the network 2 and the plurality of connection terminals is not specified, it is referred to as a “terminal”. Further, when any one of the plurality of connection terminals connected to the network is not specified, the connection terminal is referred to as “connection terminal”.

  The communication terminal device 3 and the connection terminals 4 and 5 have the same electrical configuration, and the same software is set. That is, any one of all terminals connected to the network 2 can function as a communication terminal device. Also, other terminals can function as connection terminals.

  Next, the electrical configuration of the communication terminal device 3 will be described with reference to FIG. Since the electrical configuration of the communication terminal device 3 and the connection terminals 4 and 5 are the same, the electrical configuration of the communication terminal device 3 will be described here.

  The communication terminal device 3 is provided with a CPU 20 as a controller that controls the communication terminal device 3. Connected to the CPU 20 are a ROM 21 that stores BIOS, a RAM 22 that temporarily stores various data, and an I / O interface 30 that mediates data transfer. The I / O interface 30 is connected to a hard disk drive 31 (hereinafter referred to as HDD 31) having various storage areas.

  The I / O interface 30 captures a communication device 25 for communicating with the network 2, a mouse 27, a video controller 23, a key controller 24, a camera 34 for photographing a user, and a user's voice. A microphone 35 and a CD-ROM drive 26 are connected to each other. The I / O interface 30 includes an encoder 36 for encoding an image input from the camera 34, a decoder 37 for decoding the encoded image, and a timer 38 for measuring time. And are connected. A display 28 is connected to the video controller 23. A keyboard 29 is connected to the key controller 24.

  Note that the CD-ROM 114 inserted into the CD-ROM drive 26 stores the main program of the communication terminal device 3, the communication control program of the present invention, and the like. When the CD-ROM 114 is introduced, these various programs are set up from the CD-ROM 114 to the HDD 31 and stored in a program storage area 311 (see FIG. 3) described later.

  Next, various storage areas of the HDD 31 will be described with reference to FIG. The HDD 31 includes at least a program storage area 311, its own terminal frame rate storage area 312, an I picture encoding cycle storage area 313, an encoded data storage area 314, and other information storage areas 315. The program storage area 311 stores program data necessary for the CPU 20 to execute various processes. The own terminal frame rate storage area 312 stores a frame rate to be described later. The I picture coding cycle storage area 313 stores an I picture coding cycle to be described later. In the encoded data storage area 314, communication terminal encoded data and connection terminal encoded data described later are stored.

  Next, various storage areas of the RAM 22 will be described with reference to FIG. In the RAM 22, a first frame rate storage area 221, a display time storage area 222, a first variable storage area 223, a least common multiple storage area 224, a second variable storage area 225, a second target value storage area 226, and a change display time storage are stored. An area 227 and other information storage area 228 are provided at least. The first frame rate storage area 221 stores the frame rate of the connection terminal received in the process of S104 (see FIG. 6) of the communication terminal device 3 to be described later. The display time storage area 222 stores the image display time of each terminal described later. The first variable storage area 223 stores a variable t described later. The least common multiple storage area 224 stores the least common multiple of image display times of all terminals to be described later. The second variable storage area 225 stores a variable N described later. The second target value storage area 226 stores a second target value described later. The changed display time storage area 227 stores a changed image display time to be described later.

  Next, with reference to FIG. 5, the timing for encoding an image input from the camera 34 and generating an I picture, a P picture, and a B picture will be described. A case where the communication terminal device 3 and the connection terminals 4 and 5 perform encoding at the timing shown in FIG. 5 is referred to as a “first specific example”. An I picture can be generated by decoding the I picture alone. In addition, the P picture and the B picture cannot be decoded independently. For this reason, when reproduction is desired from an arbitrary position, it is necessary to refer to the reference picture and start decoding from there. In the following description, when any of the I picture, P picture, and B picture is not specified, it is simply referred to as “picture”. FIG. 5 shows the timing at which each terminal encodes an image to generate a picture. A square in the figure represents a picture. In addition, a picture described as “I” inside a square representing a picture represents an I picture. In FIG. 5, pictures 801, 821, and 841 are I pictures. A picture in which nothing is described inside the rectangle is one of an I picture, a P picture, and a B picture.

  The uppermost pictures 801 to 809 in FIG. 5 represent the encoding timing of the communication terminal device 3. In addition, pictures 821 to 837 shown in the middle of FIG. 5 represent the encoding timing of the connection terminal 4. Also, the lowermost pictures 841 to 861 in FIG. 5 represent the encoding timing of the connection terminal 5. Further, the left-right direction in FIG. 5 represents time, and the time elapses from left to right. In FIG. 5, the timing at which the leftmost pictures 801, 821, and 841 are encoded is “0 ms”.

  In the case of the first specific example, it is assumed that the frame rate of the communication terminal device 3 is “10 fps”. Further, it is assumed that the frame rate of the connection terminal 4 is “20 fps”. Further, it is assumed that the frame rate of the connection terminal 5 is “25 fps”. The frame rate is an index indicating how many times the screen is updated per second. In the case of the communication terminal device 3, since the frame rate is “10 fps”, an image input from the camera 34 is encoded into 10 pictures per second. Also, the encoded picture can be decoded and displayed as 10 moving images by displaying 10 images per second. Further, by calculating the reciprocal of the frame rate, it is possible to calculate an image display time which is a time for displaying one image on the display 28. This image display time can also be referred to as an interval time for encoding an image input from the camera 34. In the case of the communication terminal device 3, the reciprocal of “10 fps” which is the frame rate is calculated to be “0.1 second”. “0.1 second” can be expressed as “100 milliseconds”. That is, the image display time is “100 milliseconds”. In the following description, “millisecond” is expressed as “ms”.

  As illustrated in FIG. 5, the communication terminal device 3 encodes an image every “100 ms” that is an image display time. That is, the timing for encoding the image is every "100 ms". In addition, since the frame rate of the connection terminal 4 is “20 fps”, the image display time is “50 ms”. Therefore, the timing for encoding an image is every “50 ms”. Further, since the frame rate of the connection terminal 5 is “25 fps”, the image display time is “40 ms”. Therefore, the timing for encoding the image is every “40 ms”.

  Next, processing by the video conference system 1 according to the first embodiment will be described with reference to flowcharts showing specific examples. Here, the processing will be described in order by dividing the processing by the CPU 20 of the communication terminal device 3 and the processing by the CPU 20 of the connection terminal.

  First, the first main process of the communication terminal device 3 will be described with reference to the flowchart of FIG. As shown in FIG. 6, in the first main process performed in the communication terminal device 3, first, various parameters and the like are initialized (S101). Next, one of all connection terminals connected to the network 2 is selected (S102). The process of S102 is repeatedly executed until it is determined that the frame rates of all the connected terminals have been acquired by the process of S106 described later. In the process of S102, the connection terminals connected to the network 2 are selected in order, and the connection terminals once selected are not selected redundantly. In the following description, the terminal selected by the process of S102 is referred to as “first selection terminal”.

  Next, a frame rate transmission request is made to the first selection terminal (S103). In the process of S <b> 103, frame rate request data that is data requesting the first selection terminal to transmit the frame rate of the first selection terminal to the communication terminal device 3 is transmitted via the network 2.

  Next, it is determined whether a frame rate has been received (S104). Although details will be described later, the frame rate request data transmitted to the first selection terminal by the process of S103 is received by the process of S602 (see FIG. 14) of the first selection terminal, and by the process of S603 (see FIG. 14). The frame rate of the first selection terminal is transmitted to the communication terminal device 3. In the process of S104, it is determined whether or not the frame rate transmitted by the process of S603 of the first selection terminal has been received. If the frame rate of the first selection terminal has not been received (S104: NO), then the process returns to S104 and is repeated. That is, the communication terminal device 3 stands by until the frame rate of the first selection terminal is received.

  When the frame rate of the first selected terminal is received (S104: YES), the frame rate of the first selected terminal received in the process of S104 is then stored in the first frame rate storage area 221 ( S105). Note that the process of S105 is repeatedly executed until it is determined that the frame rates of all the connected terminals have been acquired by the process of S106 described later. The first frame rate storage area 221 stores the frame rates of all connected terminals selected in the process of S102.

  Next, it is determined whether or not the frame rates of all connected terminals connected to the network 2 have been acquired (S106). In the process of S106, it is determined whether or not the frame rates of all the connected terminals are stored in the first frame rate storage area 221 by the process of S105 (S106). If the frame rates of all the connected terminals have not been acquired (S106: NO), then the process returns to S102 and is repeated. By repeating the processes of S102 to S106, the connected terminals connected to the network 2 are sequentially selected by S102 (S102), and the frame rate of the selected connected terminals is stored in the first frame rate storage area 221. (S105).

  For example, in the first specific example, when the connection terminal 4 is first selected in the process of S102, frame rate request data is transmitted from the communication terminal apparatus 3 to the connection terminal 4 via the network 2 (S103). Received by the connection terminal 4 (S602: YES, see FIG. 14). The connection terminal 4 transmits “20 fps” which is the frame rate of the connection terminal 4 to the communication terminal device 3 in accordance with the frame rate request data (S603, see FIG. 14). Then, “20 fps” that is the frame rate of the connection terminal 4 is received by the communication terminal device 3 (S104: YES) and stored in the first frame rate storage area 221 (S105). Only the frame rate of the connection terminal 4 is stored in the first frame rate storage area 221. For this reason, not all the frame rates of the connected terminals 4 and 5 have been acquired (S106: NO), and then the process returns to S102. Next, when the connection terminal 5 is selected in the process of S102, similarly to the case of the connection terminal 4, data of “25 fps” that is the frame rate of the connection terminal 5 is transmitted from the connection terminal 5 to the communication terminal apparatus 3. (S603, see FIG. 14), and is additionally stored in the first frame rate storage area 221 (S105). Since all the frame rates of the connection terminals 4 and 5 are stored in the first frame rate storage area 221, it is determined that all the frame rates of the connection terminals 4 and 5 connected to the network 2 have been acquired. (S106: YES).

  When all the frame rates of the connected terminals connected to the network 2 have been acquired (S106: YES), an encoding cycle determination process is subsequently performed (S107).

  Here, the encoding cycle determination process will be described with reference to FIG. The coding cycle determination process is a process for determining an I picture coding cycle. As described above, the communication terminal device 3 and the connection terminal encode an image input from the camera 34 of each terminal, and generate an I picture, a P picture, and a B picture. The I picture encoding cycle is a cycle for encoding an image into an I picture at the same timing in the communication terminal device 3 and the connected terminal. Although details will be described later, in the present embodiment, the communication terminal apparatus 3 and the connection terminal encode an image into an I picture at the same timing based on the I picture encoding period. The data encoded by each terminal is stored in the HDD 31 of the communication terminal device 3 (see S121 in FIG. 6, which will be described later). When the stored data is read and reproduced, for example, when fast-forwarding, for example, each terminal can send only data obtained by encoding an image into an I picture at the same timing.

  In the coding cycle determination process shown in FIG. 7, first, an image display time that is a display time of one image is calculated from the frame rate (S201). In the process of S201, the frame rate of the communication terminal apparatus 3 stored in its own terminal frame rate storage area 312 (see FIG. 3) and the frame rate of the connected terminal stored in the first frame rate storage area 221 by the process of S105. And the image display time of each terminal is calculated. This calculation is performed by obtaining the reciprocal of the frame rate. The calculated image display time of each terminal is stored in the display time storage area 222 (see FIG. 4) of the RAM 22 (S201).

  Next, the least common multiple of the image display times of all terminals is calculated from the image display times of the terminals calculated in S201. The calculation of the least common multiple of all terminals is performed by the processes of S202 to S206 described later. Hereinafter, the processing of S202 to S206 will be described.

  First, among the image display times of each terminal stored in the display time storage area 222 by the process of S201, the image display time of one terminal is selected and set as a variable t, and the first variable storage area 223 of the RAM 22 is selected. (S202). Next, an image display time other than the image display time of the terminal selected in S202 is selected (S203). Note that the process of S203 is repeatedly executed until it is determined by the process of S206 described later that the image display times of all the terminals have been selected. In the process of S203, the image display times of the communication terminal device 3 and the connection terminals 4 and 5 connected to the network 2 are selected in order, and the image display times of the terminals once selected in the processes of S202 and S203 are overlapped. Do not select.

  Next, the least common multiple of the image display time of the terminal selected by the process of S203 and the variable t is calculated (S204). Next, the least common multiple calculated by the process of S204 is set as a variable t and stored in the first variable storage area 223 of the RAM 22 (S205). That is, the least common multiple of the image display time of the terminal selected by the process of S202 and the image display time of the terminal selected by the process of S203 is updated and set as the variable t.

  Next, it is determined whether the image display times of all terminals have been selected (S206). In the process of S206, it is determined whether the image display times of all terminals have been selected by the processes of S202 and S203. If the image display times of all terminals have not been selected (S206: NO), the process returns to S202 and is repeated.

  As described above, when the processes of S203 to S203 are repeatedly executed until all the image display times are selected by the processes of S202 and S203, the least common multiple of all terminals is set as the variable t (S205). ).

  In the case of the first specific example, the frame rates stored in the first frame rate storage area 221 by the processing of S105 (see FIG. 6) are “20 fps” of the connecting terminal 4 and “25 fps” of the connecting terminal 5. is there. Also, the own terminal frame rate storage area 312 of the HDD 31 stores “10 fps” which is the frame rate of the communication terminal device 3. In the coding cycle determination process of FIG. 7, first, the image display time is calculated from the frame rate of each of these terminals (S201). The image display time is performed by obtaining the reciprocal of the frame rate. That is, the image display time of the communication terminal device 3 is calculated as “100 ms” (S201). Further, the image display time of the connection terminal 4 is calculated as “50 ms” (S201). Further, the image display time of the connection terminal 5 is calculated as “40 ms” (S201). Then, the calculated “100 ms”, “50 ms”, and “40 ms” are stored in the display time storage area 222 (S201).

  Next, among the image display times “100 ms”, “50 ms”, and “40 ms” stored in the display time storage area 222, the image display time of one terminal is selected (S202). Here, it is assumed that “100 ms” which is the image display time of the communication terminal device 3 is selected (S202). The selected “100 ms” is set as a variable t and stored in the first variable storage area 223 of the RAM 22 (S202). That is, the variable t = 100 ms is set.

  Next, an image display time other than “100 ms” which is the image display time of the terminal selected in S202 is selected (S203). Here, it is assumed that “50 ms” which is the image display time of the connected terminal 4 is selected (S203). Next, a common multiple between “50 ms” selected in the process of S203 and the variable t = 100 ms is calculated (S204). The least common multiple of “100 ms” and “50 ms” is calculated as “100 ms” (S204). Then, the calculated “100 ms” is set as a variable t, and is updated and registered in the first variable storage area 223 (S205). That is, the variable t = 100 ms is set.

  Next, it is determined whether or not the image display times of all the terminals have been selected by the processes of S202 and S203 (S206). Since the image display time of the terminal selected by the process of S202 and the process of S203 is “100 ms” of the communication terminal device 3 and “50 ms” of the connection terminal 4, “40 ms” of the connection terminal 5 is selected. Absent. For this reason, it is determined that the image display times of all terminals have not been selected (S206: NO), and the process returns to S203. Then, “40 ms” of the connection terminal 5 is selected (S203). Next, the common multiple of “40 ms” selected in the process of S203 and the variable t = 100 ms is calculated (S204). The least common multiple of “40 ms” and “100 ms” is calculated as “200 ms” (S204). Then, the calculated “200 ms” is set as a variable t, and is updated and registered in the first variable storage area 223 (S205). That is, the variable t = 200 ms is set. Since the image display times of the terminals selected by the processing of S202 and the processing of S203 are “100 ms” of the communication terminal device 3, “50 ms” of the connection terminal 4, and “40 ms” of the connection terminal 5, It is determined that the image display time has been selected (S206: YES).

  Thus, the variable t = 200 ms calculated by the processing of S202 to S206 is the least common multiple of the image display time of all terminals. “200 ms”, which is the least common multiple of the image display times of all the terminals, represents that the timings at which all the terminals encode images are the same in a “200 ms” cycle. That is, as shown in FIG. 5, when 200 ms has elapsed from the start, the picture 803 encoded by the communication terminal device 3, the picture 825 encoded by the connection terminal 4, and the picture 846 encoded by the connection terminal 5 Are encoded at the same timing. In addition, the picture 805 encoded by the communication terminal device 3, the picture 829 encoded by the connection terminal 4, and the picture 851 encoded by the connection terminal 5 when 400 ms have elapsed from the start are encoded at the same timing. Has been. Similarly, the picture 807, the picture 833, and the picture 856 when 600 ms have elapsed from the start are encoded at the same timing. Also, picture 809, picture 837, and picture 861 are encoded at the same timing when 800 ms has elapsed since the start. Thus, in 200 ms, 400 ms, 600 ms, 800 ms, 1000 ms, and the like, which are multiples of 200 ms, which is the least common multiple, the timings at which the communication terminal device 3, the connection terminal 4, and the connection terminal 5 encode images are the same. .

  In FIG. 7, when it is determined that the image display times of all terminals have been selected (S206: YES), it is subsequently determined whether or not the variable t is equal to or less than the first threshold value (S207). That is, it is determined whether the least common multiple of the image display times of all terminals is equal to or less than the first threshold (S207). The first threshold will be described later.

  If the variable t is less than or equal to the first threshold (S207: YES), then the value of the variable t is stored in the least common multiple storage area 224 (S208). As a result, the least common multiple of the image display times of all terminals is determined. Next, the least common multiple of all the terminals stored in the least common multiple storage area 224 is referred to by the processing of S208, the multiple of the least common multiple is calculated, and the multiple closest to the first target value is determined (S209). The first target value will be described later. Next, the multiple closest to the first target value determined in S209 is determined as the I picture encoding cycle (S210). In the processing of S210, the multiple closest to the first target value among the multiples of the least common multiple of all terminals is stored in the I picture encoding cycle storage area 313 of the HDD 31. As a result, the I picture encoding period is determined.

  As described above, the I picture encoding cycle is a cycle for encoding an image into an I picture at the same timing in the communication terminal device 3 and the connected terminal. The first threshold value is a threshold value provided to prevent the I picture encoding cycle from becoming long. The first threshold is set to the longest time in a range where the user wants to set the I picture encoding cycle. Then, by setting the I picture encoding period to be equal to or less than the first threshold, the I picture encoding period can be set to a range that the user wants to set. As a result, it is possible to prevent the I picture encoding cycle from becoming long. Note that the first threshold value can be arbitrarily set.

  The first target value represents the most appropriate I picture encoding cycle. The first target value is set to an ideal time at which the user wants to set the I picture encoding cycle. Then, by setting the I picture encoding cycle to a value close to the first target value, an I picture encoding cycle close to the ideal time is set. The first target value can be arbitrarily set.

  In the case of the first specific example, it is assumed that the first threshold value is 5000 ms and the first target value is 450 ms. The variable t obtained by the processing of S201 to S206 is 200 ms. Therefore, it is determined that the variable t is equal to or less than the first threshold (S207: YES). Next, “200 ms” which is the value of the variable t is stored in the least common multiple storage area 224 (S207). As a result, “200 ms” is determined to be the least common multiple of the image display times of all terminals. Next, 200 ms, 400 ms, 600 ms, 800 ms, etc., which are multiples of “200 ms”, which is the least common multiple stored in the least common multiple storage area 224, are calculated, and the first target value “450 ms” is calculated from these multiples. “400 ms”, which is the nearest multiple to, is stored in the I picture encoding cycle storage area 313 (S210). As a result, the I picture encoding period is determined to be “400 ms” (S210). Although details will be described later, the communication terminal device 3 and the connection terminals 4 and 5 simultaneously encode an image as an I picture every “400 ms” which is an I picture encoding cycle (S501 in FIG. 11 and FIG. 14). (See S615). That is, at 400 ms, 800 ms, 1200 ms, and 1600 ms, which are multiples of 400 ms, the communication terminal device 3 and the connection terminals 4 and 5 simultaneously encode an image as an I picture.

  In the process of S207, when it is determined that the variable t is not equal to or less than the first threshold (S207: NO), an image display time change process is subsequently performed (S211). Here, the image display time changing process will be described with reference to FIG. If it is determined in step S207 that the variable t, which is the least common multiple of all terminals, is not less than or equal to the first threshold value, the least common multiple is too large. That is, if this least common multiple is set to the I picture encoding cycle, the I picture encoding cycle becomes long. For this reason, it is necessary to change the image display time of at least one of the image display times of all the terminals so that the least common multiple of the image display times of all the terminals is equal to or less than the first threshold value. Furthermore, if the least common multiple after changing the image display time of at least one of the image display times of all terminals is set to a value close to the first target value, the I picture encoding cycle is more appropriately set. Can be set. In the image display time changing process shown in FIG. 8, a changed image display time that is an image display time obtained by changing at least one of the image display times of all terminals is calculated.

  In the image display time changing process shown in FIG. 8, first, the number of all terminals connected to the network 2 is set as a variable N and stored in the second variable storage area 225 (S301). Next, the value of the variable N is decremented and updated and stored in the second variable storage area 225 (S302). Next, all combinations of the N image display times are selected from the image display times of all the terminals stored in the display time storage area 222 (S303). Further, the least common multiple of the image display times of all the selected combinations is calculated (S303). Next, it is determined whether or not there is a least common multiple equal to or smaller than the first threshold in the least common multiple calculated in the process of S303 (S304). If there is no least common multiple equal to or smaller than the first threshold in the least common multiple calculated in the process of S303 (S304: NO), the process returns to S302 and is repeated. If there is a least common multiple equal to or smaller than the first threshold in the least common multiple calculated in S303 (S304: YES), the least common multiple closest to the first target value is selected, and the second target value in the RAM 22 is selected. It is stored in the storage area 226 (S305). Thus, the least common multiple that is equal to or smaller than the first threshold value and is closest to the first target value among the least common multiples calculated in the process of S303 is set as the second target value. When N = 1 (S302), multiples of the image display time of each terminal are individually calculated (S303), and the value closest to the first target value is set as the second target value (S303). S305).

  For example, as shown in FIG. 9, with respect to the image display time calculated by the process of S201 (see FIG. 7), the image display time of the communication terminal device 3 is “150 ms” and the image display time of the connection terminal 4 is “310 ms”. Assume that the image display time of the connection terminal 5 is “400 ms”. Further, it is assumed that the first threshold value is “5000 ms” and the first target value is “450 ms”. 9 shows the encoding timing of the communication terminal apparatus 3 as in the case of FIG. The middle picture represents the encoding timing of the connection terminal 4. The lowermost picture represents the encoding timing of the connected terminal 5. Further, the time elapses from left to right in FIG. Hereinafter, this example is referred to as a “second specific example”. In the case of the second specific example, the variable t becomes “37200 ms” by the processing of S202 to S206. As shown in FIG. 9, this means that the timing at which the communication terminal device 3 and the connection terminals 4 and 5 encode the image is the same at a period of 37200 ms. Then, it is determined that the variable t is equal to or greater than the first threshold value “5000 ms” (S207: NO in FIG. 7). Next, since there are three terminals connected to the network 2, that is, the communication terminal device 3 and the connection terminals 4 and 5, the variable N = 3 is set and stored in the second variable storage area 225 ( S301). Next, the variable N is decremented to be a variable N = 2, and is updated and stored in the second variable storage area 225 (S302).

  Next, from the image display times of all the terminals stored in the display time storage area 222, all combinations of two image display times that are the value of the variable N are selected, and the least common multiple is calculated. (S303). That is, “4650 ms” that is the least common multiple of “150 ms” of the communication terminal device 3 and “310 ms” of the connection terminal 4 is calculated (S303). Further, “12400 ms”, which is the least common multiple of “310 ms” of the connection terminal 4 and “400 ms” of the connection terminal 5 is calculated (S303). Further, “1200 ms” which is the least common multiple of “150 ms” of the communication terminal device 3 and “400 ms” of the connection terminal 5 is calculated (S303). Then, it is determined that the least common multiple “4650 ms”, “12400 ms”, and “1200 ms” calculated in the process of S303 includes the least common multiple that is equal to or less than “5000 ms” that is the first threshold (S304: YES). . Then, “1200 ms” that is the least common multiple closest to “450 ms” that is the first target value is selected and stored in the second target value storage area 226 (S305). Thus, “1200 ms” is set as the second target value (S305).

  When the second target value is set by the process of S305, even if a multiple is calculated for the image display time of a terminal other than the terminal used to determine the second target value, the calculated multiple is It is not the same as the two target values. For this reason, the image display time of terminals other than the terminal used for determining the second target value is changed. The image display time after the change is referred to as “changed image display time”. The changed image display time is calculated by the processing of S306 to S311 described later. Moreover, the image display time before the change and the changed image display time are determined to be close values by the processes of S306 to S311. Hereinafter, the processing of S306 to S311 will be described.

  When the second target value is set (S305), the second target value is then factored and all divisors of the second target value are calculated (S306). Next, the image display of terminals other than the terminal used when calculating the second target value determined by the process of S305 from the image display times of all the terminals stored in the display time storage area 222. One of the times is selected (S307). The process of S307 is repeatedly executed until it is determined by the process of S311 to be described later that all the image display times of terminals other than the terminal used for calculating the second target value have been selected. Do not select duplicate image display times for selected terminals.

  Next, the second target value is divided by the image display time of the terminal selected in the process of S307, and its quotient is calculated (S308). Next, a divisor that is close to the quotient calculated by the process of S308 and less than or equal to the quotient is selected from all the divisors of the second target value calculated by the process of S306 (S309). Next, the second target value is divided by the divisor of the second target value selected in the process of S309, and the quotient is determined as the changed image display time and stored in the changed display time storage area 227 (S310). ). Thereby, the changed image display time of the terminal selected by the process of S307 is determined (S310).

  Next, it is determined whether all the image display times of the terminal other than the image display time of the terminal used when calculating the second target value in the process of S307 have been selected (S311). If the image display times of all terminals have not been calculated (S311: NO), the process returns to S307 and is repeated. That is, the process is repeated until the changed image display time is calculated for all terminals other than the terminal used when calculating the second target value. If it is determined that all image display times of terminals other than the terminal used when calculating the second target value in the process of S307 are selected (S311: YES), then the image display time change process is performed. Then, the process returns to the flowchart of FIG. Then, the second target value is determined as the I picture encoding cycle (S212). In the process of S212, the second target value is stored in the I picture coding cycle storage area 313 as the I picture coding cycle.

  In the case of the second specific example, as described above, the second target value set in the process of S305 is “1200 ms”. In the process of S306, the second target value “1200 ms” is primed and all divisors of 1200 ms are calculated. Accordingly, 1, 2, 3, 6, 12, etc., which are divisors of 1200 ms, are calculated (S306). Next, among the image display times of all the terminals stored in the display time storage area 222, the image display times of the terminals other than the terminal used for calculating the second target value “1200 ms” are calculated. One of them is selected (S307). The image display time of the terminal used when calculating the second target value “1200 ms” is “150 ms” of the communication terminal device 3 and “400 ms” of the connection terminal 5. For this reason, “310 ms” of the connection terminal 4 which is the image display time of the terminal other than “150 ms” of the communication terminal device 3 and “400 ms” of the connection terminal 5 is selected (S307).

  Next, “1200 ms” that is the second target value is divided by “310 ms” that is the image display time selected in S307, and “3” that is the quotient is calculated (S308). Next, the quotient calculated by the process of S308 out of 1, 2, 3, 6, 12 and the like that are divisors of “1200 ms” that is the second target value calculated by the process of S306 “ A divisor close to “3” and equal to or less than “3” is selected (S309). Thus, “3” is selected from the divisors of the second target value (S309). Next, “1200 ms” that is the second target value is divided by “3” that is a divisor of the second target value selected by the processing of S309, and “400 ms” that is the quotient is calculated (S310). . Then, “400 ms” is determined as the changed image display time of the connected terminal 4 and stored in the changed display time storage area 227 (S310). Thereby, the changed image display time of the connection terminal 4 selected by the process of S307 is determined (S310). Next, since all terminal image display times other than the image display time of the terminal used when calculating the second target value by the processing of S307 are selected (S311: YES), next, the image display time The change process is terminated, and the process returns to the flowchart of FIG. Then, the second target value “1200 ms” is stored in the I picture coding cycle storage area 313 as the I picture coding cycle (S212). As a result, the I picture encoding period is determined to be “1200 ms” (S212).

  The initial communication terminal device 3 and the connection terminals 4 and 5 of the second specific example shown in FIG. 9 have the same timing for encoding images in a period of 37200 ms. However, if the image display time of the connection terminal 4 is changed from “310 ms” to “400 ms”, the timing at which the communication terminal device 3 and the connection terminals 4 and 5 encode the image becomes the same as shown in FIG. Becomes a period of 1200 ms. Although details will be described later, in the case of the second specific example, the communication terminal device 3 and the connection terminals 4 and 5 encode an image as an I picture at a cycle of 1200 ms. The process of setting the changed image display time “400 ms” in the connection terminal 4 will be described later.

  As described above, the I picture encoding period and the changed image display time are determined by the image display time change process (see FIG. 8) and the process of S212. The second target value is set by the processing of S301 to S305. At this time, the number of all terminals connected to the network 2 is set as a variable N (S301), the variable N is decreased by 1 (S302), and the least common multiple of all combinations of N image display times. Is calculated (S303). If there is a common multiple equal to or smaller than the first threshold among the common multiples calculated in S303, the repetitive processing of S302 to S304 is terminated (S304: YES). That is, when the value of the variable N is as large as possible and there is a least common multiple that is equal to or less than the first threshold value, the iterative process of S302 to S304 is ended. Thereby, it is not necessary to calculate the changed image display time by performing the processing of S307 to S310 for the image display time of N terminals among the terminals connected to the network 2. That is, it is not necessary to change the image display time of as many terminals as possible.

  Further, the least common multiple closest to the first target value is set as the second target value (S305), and this second target value is set as the I picture encoding cycle (see S212 in FIG. 7). As a result, the least common multiple that is equal to or smaller than the first threshold value and closest to the first target value can be set as the I picture encoding cycle.

  Further, the changed image display time is calculated by the processing of S306 to S311. Generally, the image display time is set as a time during which the terminal can encode an image. For this reason, if the changed image display time is set to be shorter than the image display time before the change, the terminal becomes shorter than the time during which the image can be encoded, which may cause a problem. In the present embodiment, the divisor of the second target value is obtained in the process of S306. Then, a divisor equal to or smaller than the quotient calculated by the process of S308 is selected from the divisors of the second target value calculated by the process of S306 (S309). In this way, the changed image display time is longer than the image display time before the change (S310). For example, in the case of the second specific example, the changed image display time is set to “400 ms” with respect to “310 ms” of the image display time before the change. That is, the changed image display time is longer than the image display time before the change. That is, since the image change display time is longer than the time during which the terminal can encode the image, there is no problem. In the case of the second specific example, if “6”, which is a divisor greater than the quotient “3”, is set by the processing of S309, the changed image display time becomes “200 ms” ( S310). That is, the changed image display time “200 ms” is shorter than the image display time “310 ms” before the change, and as described above, becomes shorter than the time that the terminal can encode the image. Therefore, there is a risk of malfunction.

  In the process of S309, a divisor close to the quotient calculated by the process of S308 is selected from the divisors of the second target value calculated by the process of S306. For this reason, the changed image display time calculated in S310 is close to the image display time before the change. That is, the change in image display time can be reduced. Since the change in the image display time is small, the change in smoothness when displaying a moving image can be reduced.

  Returning to the flowchart of FIG. When the I picture encoding period is determined by the process of S210 or the process of S212, the encoding period determining process is terminated, and the process returns to the first main process shown in FIG. Next, it is determined whether or not the frame rate of the communication terminal device 3 needs to be changed (S108). In the process of S108, the changed image display time stored in the changed display time storage area 227 is referred to. Then, it is determined whether or not the frame rate of the communication terminal device 3 needs to be changed. If the changed image display time of the communication terminal device 3 is stored in the changed display time storage area 227, it is determined that the frame rate needs to be changed. If the changed image display time of the communication terminal device 3 is not stored in the changed display time storage area 227, it is determined that there is no need to change the frame rate.

  When it is necessary to change the frame rate of the communication terminal device 3 (S108: YES), the frame rate of the communication terminal device 3 is changed (S109). In the process of S109, the frame rate is calculated from the changed image display time of the communication terminal device 3 stored in the changed display time storage area 227. The calculated frame rate is updated and stored in the own terminal frame rate storage area 312 of the HDD 31. Thereby, the frame rate of the communication terminal device 3 is changed (S109). Next, a connection terminal is selected (S110). In the process of S108, when it is determined that it is not necessary to change the frame rate of the communication terminal device 3 (S108: NO), the connection terminal is subsequently selected (S110).

  In the processing of S110, one of all connection terminals connected to the network 2 is selected. In the following description, the connection terminal selected by the process of S110 among all the connection terminals is referred to as a “second selection terminal”. Next, an I picture encoding cycle is transmitted to the second selection terminal (S111). In the process of S111, the I picture encoding period stored in the I picture encoding period storage area 313 by the process of S210 or S212 (see FIG. 7) is transmitted to the second selection terminal. Note that the I picture encoding cycle transmitted by the process of S111 is received by the process of S604 of the connecting terminal (see FIG. 14). Next, it is determined whether or not the frame rate needs to be changed for the second selected terminal (S112). In the process of S112, it is determined whether or not it is necessary to change the frame rate of the second selected terminal by referring to the changed image display time stored in the changed display time storage area 227. If the changed image display time of the second selected terminal is stored in the changed display time storage area 227, it is determined that the frame rate needs to be changed (S112: YES). If the changed image display time of the second selected terminal is not stored in the changed display time storage area 227, it is determined that there is no need to change the frame rate (S112: NO).

  If it is determined that there is no need to change the frame rate (S112: NO), then “no request data”, which is data indicating that there is no request to change the frame rate, is sent to the second selection terminal. It is transmitted (S113). The no-request data transmitted by the process of S113 is received by the process of S606 of the connection terminal described later. Next, a first confirmation process is performed (S116).

  If it is determined by the process of S112 that the frame rate needs to be changed (S112: YES), then “requested data”, which is data indicating that there is a request to change the frame rate, It is transmitted to the second selection terminal (S114). The requested data transmitted by the process of S114 is received by the process of S606 of the connection terminal described later. Next, the changed frame rate is transmitted to the second selected terminal (S115). The changed frame rate is a frame rate calculated from the changed image display time of the second selection terminal stored in the changed display time storage area 227. Note that the changed frame rate transmitted by the process of S115 is received by the process of S608 of the connection terminal described later. Then, the frame rate of the connection terminal is changed to the changed frame rate by the process of S609 of the connection terminal described later.

  If the changed frame rate is transmitted to the second selection terminal by the process of S115, then a first confirmation process is performed (S116). Here, the first confirmation process will be described with reference to FIG. When the I picture encoding period is transmitted by the process of S111 or when the changed frame rate is transmitted by the process of S115, the I picture encoding period and the changed frame rate are appropriately set by packet loss or the like. There is a risk that it will not be set to the second-choice terminal. The first confirmation process is a process of confirming that the I picture encoding cycle transmitted by the process of S111 and the changed frame rate transmitted by the process of S115 are appropriately set in the connection terminal.

  In the first confirmation process shown in FIG. 10, first, setting information request data, which is data for requesting transmission of an I picture encoding period and a frame rate, is transmitted to the second selection terminal (S401). Next, it is determined whether or not the I picture encoding cycle and the frame rate transmitted from the second selection terminal have been received (S402). The setting information request data transmitted by the process of S401 is received by the process of S701 (see FIG. 15) of the second selection terminal described later. Then, the I picture encoding period and the frame rate set in the second selection terminal are transmitted by the processing of S702 of the second selection terminal described later. In the process of S402, it is determined whether or not the I picture encoding cycle and the frame rate transmitted by the process of S702 of the second selection terminal have been received.

  If the I picture encoding period and the frame rate have not been received (S402: NO), then the process returns to S402 and is repeated. That is, it waits until an I picture encoding cycle and a frame rate are received. If the I picture encoding cycle and the frame rate are received (S402: YES), then the received I picture encoding cycle and the frame rate are set to the set I picture encoding cycle and the frame rate. Is determined whether or not (S403). In the process of S403, it is determined whether or not the I picture encoding period received by the process of S402 and the I picture encoding period determined in the process of S210 or S212 (see FIG. 7) match. The When the second selection terminal is a connection terminal that has transmitted the changed frame rate by the process of S115 of the communication terminal apparatus 3, the frame rate received by the process of S402 matches the changed frame rate. Is determined (S403). If the second selection terminal is a connection terminal to which no-request data is transmitted in the process of S113 of the communication terminal device 3, the frame rate received by the process of S402 and the process of S104 (see FIG. 6). ) Match with the received frame rate, it is determined that the frame rates match (S403).

  When the I picture encoding cycle matches and the frame rate matches (S403: YES), it is data informing that it is not necessary to reset the I picture encoding cycle and the frame rate. “No reset request data” is transmitted to the second selected terminal (S404). The no reset request data transmitted by the process of S404 is received by the process of S703 of the second selection terminal (see FIG. 15, described later). When the data without reset request is transmitted to the second selection terminal (S404), the first confirmation process is terminated, and the process returns to the first main process shown in FIG.

  If the I picture encoding cycle does not match or the frame rate does not match (S403: NO), it is necessary to reset either the I picture encoding cycle or the frame rate. “Data with reset request” that is data to be notified is transmitted to the second selected terminal (S405). The data with reset request transmitted by the process of S405 is received by the process of S703 of the second selection terminal. If the data with reset request is transmitted to the second selection terminal (S405), the first confirmation process is then terminated and the process returns to the first main process shown in FIG.

  When the first confirmation process (S116) is completed, it is next determined whether or not it is necessary to reset the I picture encoding period or the changed frame rate to the second selected terminal (S117). In the process of S117, when the data without reset request is transmitted to the second selection terminal by the process of S404 (see FIG. 10), the I picture encoding cycle and the changed frame rate are reset to the second selection terminal. It is judged that there is no need to do. In the process of S117, if the data with reset request is transmitted to the second selection terminal by the process of S405 (see FIG. 10), the I picture encoding cycle or the changed frame rate is set to the second selection terminal. It is determined that resetting is necessary.

  If it is determined that the I picture encoding cycle or the changed frame rate needs to be reset in the second selected terminal (S117: YES), then the I picture encoding cycle or the changed frame rate Is transmitted to the second selection terminal (S118). In the process of S118, if it is determined by the process of S403 (see FIG. 10) that both the I picture encoding cycle and the frame rate do not match, the I picture encoding cycle and the changed frame rate are calculated. Transmit to the second selected terminal. In the process of S118, when it is determined that the I-picture encoding periods match and the frame rates do not match in the process of S403 (see FIG. 10), only the changed frame rate is sent to the second selection terminal. Send. Also, in the process of S118, if it is determined that the I picture encoding periods do not match and the frame rates match in the process of S403 (see FIG. 10), only the I picture encoding period is changed to the second. Send to selected terminal. That is, data that needs to be reset in the second selection terminal among the I picture encoding period and the changed frame rate is transmitted to the second selection terminal. Note that the I picture encoding cycle or the changed frame rate transmitted in the process of S118 is received in the process of S612 of the second selection terminal, and is reset in the process of S613 (see FIG. 14).

  When the I picture encoding period or the changed frame rate is transmitted to the second selection terminal (S118), the process returns to S116 and the process is repeated. That is, until the I picture encoding period and the frame rate set in the second selected terminal match the I picture encoding period and the changed frame rate transmitted from the communication terminal device 3 to the second selected terminal, The processing of S116 to S118 is repeated.

  When it is determined that it is not necessary to reset the I-picture encoding period or the changed frame rate to the second selected terminal (S117: NO). Next, it is determined whether all connected terminals have been selected (S119). In the process of S119, it is determined whether or not all the connected terminals connected to the network 2 have been selected by the process of S110. If there is a connected terminal that is not selected in the process of S110 (S119: NO), then the process returns to S110 and the process is repeated. That is, all the connected terminals are selected, and the processes of S110 to S119 are performed.

  In the case of the first specific example, since the changed image display time of the communication terminal device 3 is not stored in the changed display time storage area 227, it is determined that there is no need to change the frame rate of the communication terminal device 3 ( S108: NO). Next, the connection terminal is selected (S110). Here, it is assumed that the connection terminal 4 is selected (S110). Next, an I picture encoding cycle is transmitted to the connecting terminal 4 (S111). In the case of the first specific example, the I picture encoding period is fixed to “400 ms” by the process of S210 in FIG. Therefore, “400 ms”, which is the I picture encoding period stored in the I picture encoding period storage area 313, is transmitted to the connecting terminal 4 (S111). The transmitted I picture encoding period “400 ms” is received by the processing of S604 of the connecting terminal 4 (see FIG. 14). Next, since the changed image display time of the connection terminal 4 is not stored in the change display time storage area 227, it is determined that there is no need to change the frame rate of the connection terminal 4 (S112: NO). Next, “no request data” that is data indicating that there is no request to change the frame rate is transmitted to the connection terminal 4 (S113). The no-request data transmitted by the process of S113 is received by the process of S606 (see FIG. 14) of the connection terminal 4.

  Next, a first confirmation process (S116) is performed. In the first confirmation process shown in FIG. 10, setting information request data, which is data for requesting transmission of an I picture encoding period and a frame rate, is transmitted to the connection terminal 4 (S401). Here, in the case of the first specific example, “400 ms” that is the I picture encoding period transmitted to the connection terminal 4 by the process of S111 is appropriately received by the connection terminal 4 (S604 in FIG. 14), and the connection terminal 4 is set (S605 in FIG. 14). Further, the frame rate of the connection terminal 4 is not changed (S113). In this case, when it is determined that the I picture encoding period “400 ms” and the frame rate “20 fps” transmitted from the connected terminal 4 are received (S402: YES), the received I picture code is subsequently received. It is determined whether or not the encoding period “400 ms” and the frame rate “20 fps” match the set I picture encoding period and the frame rate (S403). The I picture encoding period determined by the process of S210 is “400 ms”. Further, the communication terminal device 3 transmits no-request data to the connection terminal 4 by the process of S113. Therefore, the frame rate “20 fps” of the connection terminal 4 is not changed. Therefore, the I picture encoding period “400 ms” and the frame rate “20 fps” received in the process of S402 are received by the process of S104 and the I picture encoding period “400 ms” determined by the process of S210. It is determined that it matches the frame rate “20 fps” (S403: YES). Next, “data without reset request” that is data notifying that it is not necessary to reset the I picture encoding cycle and the frame rate is transmitted to the connection terminal 4 (S404). Next, the first confirmation process is terminated, and the process returns to the first main process shown in FIG.

  When the first confirmation process (S116) is completed, since the data without reset request is transmitted to the connecting terminal 4 by the process of S404 (see FIG. 10), the I picture encoding cycle or the frame rate Is determined not to need to be reset in the connection terminal 4 (S117: NO).

  Next, it is determined that the connection terminal 5 is not selected in the process of S110 (S119: NO), the process returns to S110, and the connection terminal 5 is selected. Then, “400 ms” that is the I picture encoding cycle is transmitted to the connecting terminal 5 (S111). Next, since the changed image display time of the connected terminal 5 is not stored in the changed display time storage area 227, it is determined that there is no need to change the frame rate of the connected terminal 5 (S112: NO). Next, unrequested data is transmitted to the connection terminal 5 (S113).

  Next, a first confirmation process (S116) is performed. Here, in the case of the first specific example, “400 ms”, which is the I picture encoding period transmitted to the connection terminal 5 by the process of S111, is appropriately received by the connection terminal 5 (S604 in FIG. 14). It is assumed that the terminal 5 is set (S605 in FIG. 14). Further, the frame rate “25 fps” of the connection terminal 5 is not changed (S113). In this case, if it is determined that the I picture encoding period “400 ms” and the frame rate “25 fps” transmitted from the connection terminal 5 have been received (S402: YES), the I picture encoding period “400 ms” is received in the process of S402. When the I picture encoding period “400 ms” and the frame rate “25 fps” match the I picture encoding period “400 ms” determined by the process of S210 and the frame rate “25 fps” received by the process of S104. Determination is made (S403: YES). Next, no reset request data is transmitted to the connection terminal 5 (S404). Next, the first confirmation process is terminated, and the process returns to the first main process shown in FIG.

  When the first confirmation process (S116) is completed, since the data without reset request is transmitted to the connecting terminal 5 by the process of S404 (see FIG. 10), the I picture encoding cycle or the frame rate It is determined that it is not necessary to reset the connection terminal 5 (S117: NO). Next, it is determined that all the connection terminals 4 and 5 connected to the network 2 have been selected (S119: YES).

  In the case of the second specific example, since the changed image display time of the communication terminal device 3 is not stored in the changed display time storage area 227, it is determined that there is no need to change the frame rate of the communication terminal device 3 ( S108: NO). Next, a connection terminal is selected (S110). Here, it is assumed that the connection terminal 4 is selected (S110). Next, an I picture encoding cycle is transmitted to the connecting terminal 4 (S111). In the case of the second specific example, the I picture is determined to be “1200 ms” by the process of S212 in FIG. Therefore, “1200 ms”, which is the I picture encoding period stored in the I picture encoding period storage area 313, is transmitted to the connecting terminal 4 (S111). Next, it is determined whether it is necessary to change the frame rate. By the process of S310 of FIG. 8, “400 ms” that is the changed image display time of the connection terminal 4 is stored in the display time storage area 222. For this reason, it is determined that the frame rate needs to be changed (S112: YES). Next, “requested data” which is data indicating that there is a request to change the frame rate is transmitted to the connecting terminal 4 (S114). The requested data transmitted by the process of S114 is received by the process of S606 (see FIG. 14) of the connection terminal 4. Next, the changed frame rate is transmitted to the connecting terminal 4 (S115). The changed frame rate is calculated by calculating the reciprocal of “400 ms” that is the changed image display time of the connected terminal 4 stored in the display time storage area 222. Thereby, the changed frame rate is calculated as “2.5 fps” and transmitted to the connection terminal 4 (S115).

  Next, a first confirmation process (S116) is performed. Here, in the case of the second specific example, “1200 ms” that is the I picture encoding cycle transmitted to the connection terminal 4 by the process of S111 is appropriately received by the connection terminal 4 (S604 in FIG. 14), and the connection It is assumed that the terminal 4 is set (S605 in FIG. 14). Further, it is assumed that the changed frame rate “2.5 fps” transmitted to the connection terminal 4 by the process of S115 is not properly received due to packet loss or the like, and the frame rate of the connection terminal 4 is set to “2 fps”. In this case, if it is determined that the I picture encoding cycle “1200 ms” and the frame rate “2 fps” transmitted from the connected terminal 4 are received (S402: YES), then the process of S403 is performed. Is called. In the process of S403, it is determined that the I picture encoding period “1200 ms” received in the process of S402 and the I picture encoding period determined by the process of S210 match “1200 ms”. However, it is determined that the frame rate “2 fps” received in the process of S402 does not match the changed frame rate “2.5 fps” transmitted in the process of S115 (S403: NO). Next, “data with reset request” that is data indicating that it is necessary to reset either the I picture encoding cycle or the frame rate is transmitted to the connection terminal 4 (S405). In the case of the second specific example, since it is necessary to change the frame rate, the reset request data includes information that the frame rate needs to be changed. The data with reset request transmitted by the process of S405 is received by the process of S703 (see FIG. 15) of the connection terminal 4. Next, the first confirmation process is terminated, and the process returns to the first main process shown in FIG.

  When the first confirmation process (S116) is completed, since the data with reset request is transmitted to the connecting terminal 4 by the process of S405 (see FIG. 10), the I picture encoding cycle or the changed frame It is determined that it is necessary to reset the rate to the connection terminal 4 (S117: YES). Next, the I picture encoding period or the changed frame rate is transmitted to the second selection terminal (S118). In the case of the second specific example, it is determined by the processing of S403 (see FIG. 10) that the I picture encoding periods match and the frame rates do not match, so only the changed frame rate “2.5 fps” is obtained. It is transmitted to the connection terminal 4 (S118). The changed frame rate “2.5 fps” transmitted in the process of S118 is received in the process of S612 of the connection terminal 4, and is reset in the process of S613 (see FIG. 14). In the case of the second specific example, it is assumed that the changed frame rate “2.5 fps” transmitted in the process of S118 is normally set in the connection terminal 4 (see S613 in FIG. 14).

  Next, the process returns to S116 and is repeated. Since the changed frame rate “2.5 fps” is normally set in the connection terminal 4, the I picture encoding period “1200 ms” and the frame rate “2.5 fps” received in the process of S 402 are changed by the process of S 210. It is determined that the determined I picture encoding cycle “1200 ms” matches the changed frame rate “2.5 fps” (S403: YES). Next, “data without reset request” that is data notifying that it is not necessary to reset the I picture encoding cycle and the frame rate is transmitted to the connection terminal 4 (S404). Next, the first confirmation process is terminated, and the process returns to the first main process shown in FIG.

  When the first confirmation process (S116) is completed, since the data without reset request is transmitted to the connecting terminal 4 by the process of S404 (see FIG. 10), the I picture encoding cycle or the frame rate Is determined not to need to be reset in the connection terminal 4 (S117: NO).

  Next, it is determined that the connection terminal 5 is not selected in the process of S110 (S119: NO), the process returns to S110, and the connection terminal 5 is selected. And the process of S110-S119 is performed with respect to the connecting terminal 5. FIG. Then, it is determined that all the connection terminals 4 and 5 connected to the network 2 have been selected (S119: YES).

  When all the connected terminals connected to the network 2 are selected by the process of S110 (S119: YES), subsequently, an encoding instruction that is data representing an instruction to start encoding is transmitted to all the connected terminals. Data is transmitted (S120). The encoded instruction data transmitted by the process of S120 is received by the process of S614 (see FIG. 14) of the connected terminal. Next, a recording process is performed (S121).

  Here, the recording process will be described with reference to FIG. The recording process is a process in which each terminal connected to the network 2 stores data obtained by encoding an image. In the recording process shown in FIG. 11, first, an encoding process is performed in the communication terminal device 3 (S501). In the processing of S501, image data input from the camera (see FIG. 2) is encoded by the encoder 36. At this time, an I picture, a P picture, and a B picture, which are data obtained by encoding an image, are generated. In the processing of S501, an image is encoded as an I picture at the I picture encoding cycle stored in the I picture encoding cycle storage area 313.

  Next, the image data encoded by the process of S501 is stored in the encoded data storage area 314 (see FIG. 3) of the HDD 31 as data encoded by the communication terminal device 3 (S502). That is, it is recorded. In the following description, image data encoded by the communication terminal device 3 is referred to as “communication terminal encoded data”. Next, it is determined whether or not image data encoded in the connection terminal (hereinafter referred to as “connection terminal encoded data”) has been received (S503). In the process of S503, it is determined whether or not the connection terminal encoded data encoded by the process of S615 (see FIG. 14) of the connection terminal described later and transmitted by the process of S616 (see FIG. 14) is received. . The connection terminal encoded data includes an I picture, a P picture, and a B picture, but an image is encoded as an I picture in an I picture encoding cycle. That is, the communication terminal device 3 and the connecting terminal encode an image as an I picture at the same I picture encoding cycle. In the following description, the I picture of each terminal encoded in the I picture encoding cycle is referred to as “common I picture”.

  When the connection terminal encoded data transmitted from the connection terminal is received (S503: YES), the encoded connection terminal is identified with reference to the received connection terminal encoded data ( S504). Next, the connection terminal encoded data received in S503 is stored in the encoded data storage area 314 of the HDD 31 as data encoded in the connection terminal identified by the processing in S504 (S505). ). That is, it is recorded. Thereby, in the encoded data storage area 314, data obtained by encoding an image by the communication terminal device 3 and the connection terminal is stored.

  Next, it is determined whether or not an instruction to end the recording process (hereinafter referred to as “recording end instruction”) is input by the user via the keyboard 29 and the mouse 27 (S506). Also, in the process of S503, even when the connection terminal encoded data transmitted from the connection terminal is not received (S503: NO), it is determined whether or not a recording end instruction is input (S506). If the recording end instruction has not been input (S506: NO), the process returns to S501 and the process is repeated. Thereby, storage of the communication terminal encoded data and the connection terminal encoded data is continued. That is, recording continues.

  If a recording end instruction is input (S506: YES), then recording is ended (S507). Next, the recording process is terminated, and the process returns to the flowchart of FIG. As shown in FIG. 6, when the recording process is finished, the first main process is finished.

  In addition, when the recording process shown in FIG. 11 is being performed, a video conference is being performed. Therefore, although not shown in FIG. 11, the connected terminal encoded data received in the process of S503 is decoded by the decoder 37 and displayed on the display 28. An image input from the camera 34 of the communication terminal device 3 is also displayed on the display 28 at the same time. Thereby, the state of the user who uses all the terminals connected to the network 2 is displayed on the display 28, and a video conference can be performed.

  Although not shown in FIG. 11, image data encoded by all the terminals connected to the network 2 is transmitted and received between all the terminals connected to the network 2. And it decodes in each terminal and is displayed on the display 28 of each terminal. Thereby, a video conference can be performed between all terminals.

  Although not shown in FIG. 11, the voice input by the microphone 35 of each terminal is also encoded as voice data and transmitted / received between all the terminals. Then, the sound is decoded and reproduced in each terminal. The audio data of each terminal is stored in the encoded data storage area 314 of the HDD 31 of the communication terminal device 3. That is, the encoded data storage area 314 stores communication terminal encoded data, connection terminal encoded data, and audio data of each terminal.

  Further, the communication terminal encoded data, the connection terminal encoded data, and the audio data of each terminal include time information measured using a timer 38 provided in each terminal.

  In the case of the first specific example, encoding instruction data, which is data representing an instruction to start encoding, is transmitted to the connection terminals 4 and 5 (S120). Next, the recording process shown in FIG. 11 is performed (S121). In the following description, the recording process of FIG. 11 will be described with reference to FIG. In addition to the timing at which the communication terminal device 3 and the connection terminals 4 and 5 shown in FIG. 5 encode an image, FIG. 12 further generates a common I picture every I picture encoding cycle “400 ms”. It shows how it is. As shown in FIGS. 11 and 12, the communication terminal apparatus 3 encodes an image input from the camera 34 every 100 ms, and generates an I picture, a P picture, and a B picture (S501). At this time, an I picture is generated every “400 ms” which is an I picture encoding cycle (S501). In FIG. 12, a picture 801 is generated as an I picture at 0 ms, a picture 805 is generated as an I picture at 400 ms, and a picture 809 is generated as an I picture at 800 ms (S501). Although not shown, similarly, pictures of 1200 ms, 1600 ms, etc. are generated as I pictures (S501). Then, the communication terminal encoded data encoded by the process of S501 is stored in the encoded data storage area 314 (S502).

  Further, the connection terminal 4 and the connection terminal 5 encode the image input from the camera 34 (see S615 in FIG. 14), and transmit the connection terminal encoded data to the communication terminal device 3 (see S616 in FIG. 14). . The connection terminal 4 encodes an image every 50 ms to generate connection terminal encoded data (S615 in FIG. 14). At this time, the connecting terminal 4 generates an I picture every “400 ms” which is the I picture encoding cycle (S615 in FIG. 14). In FIG. 12, a picture 821 is generated as an I picture at 0 ms, a picture 829 is generated as an I picture at 400 ms, and a picture 837 is generated as an I picture at 800 ms (S615 in FIG. 14). Although not shown, similarly, pictures of 1200 ms, 1600 ms, etc. are generated as I pictures (S615 in FIG. 14). Then, the connection terminal 4 transmits the connection terminal encoded data generated by the process of S615 to the communication terminal device 3 (see S616 in FIG. 14).

  Further, the connection terminal 5 encodes an image every 40 ms to generate connection terminal encoded data (S615 in FIG. 14). At this time, the connecting terminal 5 generates an I picture every “400 ms” which is the I picture encoding cycle (S615 in FIG. 14). In FIG. 12, a picture 841 is generated as an I picture at 0 ms, a picture 851 is generated as an I picture at 400 ms, and a picture 861 is generated as an I picture at 800 ms (S615 in FIG. 14). Although not shown, similarly, pictures of 1200 ms, 1600 ms, etc. are generated as I pictures (S615 in FIG. 14). And the connecting terminal 5 transmits the connecting terminal encoded data produced | generated by the process of S615 to the communication terminal device 3 (refer S615 of FIG. 14).

  When the connection terminal encoded data transmitted from the connection terminal 4 is received (S503: YES), the connection terminal encoded by the connection terminal 4 with reference to the received connection terminal encoded data is subsequently performed. It is identified that the data is encoded data (S504). Next, the connection terminal encoded data received in S503 is stored in the encoded data storage area 314 as data encoded in the connection terminal 4 identified by the process in S504 (S505).

  In addition, when the connection terminal encoded data transmitted from the connection terminal 5 is received (S503: YES), the connection terminal 5 is then encoded with reference to the received connection terminal encoded data. It is identified that it is connection terminal encoded data (S504). Next, the connection terminal encoded data received in S503 is stored in the encoded data storage area 314 as data encoded in the connection terminal 5 identified in the process of S504 (S505).

  By repeating the processing of S501 to S506, the data encoded by the communication terminal device 3 and the connection terminals 4 and 5 are stored in the encoded data storage area 314. That is, it is recorded. When a recording end instruction is input (S506: YES), the recording process is ended. Further, the first main process in FIG. 6 is terminated.

  By the recording process shown in FIG. 11, the encoded data storage area 314 stores data obtained by encoding an image by each terminal as shown in FIG. At this time, all terminals generate an I picture every “400 ms”, which is the I picture encoding period. That is, in FIG. 12, the picture 801, the picture 821, and the picture 841 are generated as I pictures at the same timing in 0 ms. Also, the picture 805, the picture 829, and the picture 851 are generated as an I picture at the same timing in 400 ms. A picture 809, a picture 837, and a picture 861 are generated as an I picture at the same timing in 800 ms.

  In the case of the second specific example, as in the case of the first specific example, by performing the processing of S501 to S507, each terminal displays an image in the encoded data storage area 314 as shown in FIG. The encoded data is stored. At this time, all terminals generate an I picture every “1200 ms”, which is the I picture encoding period. That is, in 1200 ms, 2400 ms, 3600 ms, etc., all terminals generate I pictures. Further, the communication terminal device 3 encodes an image every 150 ms and generates an I picture, a P picture, and a B picture. Further, the connecting terminal 4 encodes an image every 400 ms to generate an I picture, a P picture, and a B picture. The connecting terminal 5 encodes an image every 400 ms to generate an I picture, a P picture, and a B picture.

  The initial communication terminal device 3 and the connection terminals 4 and 5 of the second specific example shown in FIG. 9 have the same timing for encoding images in a period of 37200 ms. However, since the image display time of the connection terminal 4 is changed from “310 ms” to “400 ms”, the timing at which the communication terminal device 3 and the connection terminals 4 and 5 encode the image becomes the same as shown in FIG. Is a period of 1200 ms. The communication terminal device 3 and the connection terminals 4 and 5 encode an image as an I picture at a cycle of “1200 ms” which is an I picture encoding cycle.

  Next, with reference to FIG. 14, the second main process performed in the connection terminal will be described. In the second main process shown in FIG. 14, first, initialization is performed (S601). In the process of S601, initialization of various parameters and the like is performed.

  Next, it is determined whether or not the frame rate request data transmitted by the process of S103 of the communication terminal device 3 (see FIG. 6) has been received (S602). If the frame rate request data has not been received (S602: NO), the process returns to S602 and the process is repeated. That is, the connection terminal is on standby until the frame rate request data is received. When the frame rate request data is received (S602: YES), the frame rate of the connected terminal is subsequently transmitted to the communication terminal device 3 (S603). In the process of S603, the frame rate stored in its own terminal frame rate storage area 312 (see FIG. 3) is transmitted to the communication terminal apparatus 3 (S603). As described above, the frame rate of the connection terminal transmitted to the communication terminal apparatus 3 by the process of S603 is received by the process of S104 of the communication terminal apparatus 3 (see FIG. 6).

  Next, it is determined whether or not the I picture encoding cycle transmitted by the process of S111 of the communication terminal apparatus 3 (see FIG. 6) has been received (S604). If the I picture encoding cycle has not been received (S604: NO), the process returns to S604 and is repeated. That is, the connected terminal is on standby until an I picture encoding cycle is received. If the I picture encoding cycle is received (S604: YES), then the I picture encoding cycle is set in the connected terminal (S605). In the process of S605, the I picture encoding period received by the process of S604 is stored in the I picture encoding period storage area 313. As a result, the I picture encoding period is set in the connected terminal (S605).

  Next, it is determined whether or not no-request data transmitted by the process of S113 of the communication terminal apparatus 3 or requested data transmitted by the process of S114 of the communication terminal apparatus 3 is received (S606). If no request data or no request data has been received (S606: NO), the process returns to S606 and is repeated. In other words, the connection terminal waits until no-request data or requested-data is received.

  If unrequested data or requested data is received (S606: YES), it is then determined whether the data received by the processing of S606 is requested data (S607). If the data received by the process of S606 is requested data (S607: YES), then the changed frame rate transmitted by the process of S115 of the communication terminal device 3 (see FIG. 6) is received. It is determined whether it has been done (S608). If the changed frame rate has not been received (S608: NO), the process returns to S608 and the process is repeated. That is, the connected terminal is waiting until the changed frame rate is received.

  When the changed frame rate is received (S608: YES), the frame rate is subsequently changed (S609). In the process of S609, the changed frame rate received by the process of S608 is updated and stored in the own terminal frame rate storage area 312 of the HDD 31. As a result, the frame rate of the connected terminal is changed (S609). Next, a second confirmation process is performed (S610). In addition, when the data received by the process of S606 is no request data (S607: NO), a second confirmation process is subsequently performed (S610).

  Here, the second confirmation processing will be described with reference to FIG. As described above, the communication terminal device 3 confirms the frame rate and the I picture encoding cycle of the connected terminal by the first confirmation process (see FIG. 10). The second confirmation process is a process for confirming the frame rate and the I picture encoding period of the connected terminal by the first confirmation process of the communication terminal device 3.

  In the second confirmation process shown in FIG. 15, it is first determined whether or not the setting information request data transmitted by the process of S401 of the communication terminal apparatus 3 has been received (S701). The setting information request data is data for requesting transmission of an I picture encoding cycle and a frame rate. If the setting information request data has not been received (S701: NO), the process returns to S701 and the process is repeated. That is, it waits until setting information request data is received.

  When the setting information request data is received (S701: YES), the I picture encoding period and the frame rate of the connected terminal are transmitted to the communication terminal apparatus 3 (S702). In the processing of S <b> 702, the frame rate stored in its own terminal frame rate storage area 312 and the I picture encoding cycle stored in the I picture encoding cycle storage area 313 are transmitted to the communication terminal device 3.

  Next, it is determined whether or not data with reset request (see S405 in FIG. 10) or data without reset request (see S404 in FIG. 10) transmitted from the communication terminal apparatus 3 has been received (S703). ). If data with reset request or data without reset request has not been received (S703: NO), then the process returns to S703 and is repeated. That is, the connecting terminal is waiting. If data with reset request or data without reset request has been received (S703: YES), the second confirmation process is terminated, and the process returns to the second main process shown in FIG.

  Next, it is determined whether or not the data received in the process of S703 is data with a reset request (S611). If the data received in the process of S703 is data with a reset request (S611: YES), then the I picture code transmitted by the process of S118 of the communication terminal apparatus 3 (see FIG. 6). It is determined whether a change period or a changed frame rate has been received (S612). As described above, in the process of S118 of the communication terminal apparatus 3, data that needs to be reset in the connection terminal is transmitted to the connection terminal out of the I picture encoding cycle and the changed frame rate.

  When the I picture encoding period or the changed frame rate has not been received (S612: NO), the process returns to S612 and is repeated. That is, the connecting terminal is waiting. When the I picture encoding cycle or the changed frame rate is received (S612: YES), the I picture encoding cycle or the changed frame rate received in the process of S612 is then transmitted to the connecting terminal 4. It is reset (S613). That is, when an I picture encoding cycle is received, the I picture encoding cycle is updated and stored in the I picture encoding cycle storage area 313 (S613). When the changed frame rate is received, the changed frame rate is updated and stored in the own terminal frame rate storage area 312 (S613). Next, the process returns to S610 and is repeated.

  If the data received in the processing of S703 is data without a reset request, it is determined that the data is not with a reset request (S611: NO). Next, it is determined whether or not the encoding instruction data transmitted to the terminal device has been received by the processing of S120 of the communication terminal device 3 (see FIG. 6) (S614). If the encoding instruction data has not been received (S614: NO), the process returns to S614 and the process is repeated. That is, the connected terminal is on standby until the encoding instruction data is received.

  When the encoding instruction data is received (S614: YES), the encoding process is subsequently performed (S615). In the process of S615, image data input from the camera (see FIG. 2) is encoded by the encoder. At this time, an I picture, a P picture, and a B picture, which are data obtained by encoding an image, are generated. In the process of S615, an image is encoded as an I picture at the I picture encoding period stored in the I picture encoding period storage area 313 (see FIG. 4).

  Next, connection terminal encoded data, which is image data encoded in the connection terminal by the processing of S615, is transmitted to the communication terminal device 3 (S616). The connection terminal encoded data transmitted to the communication terminal apparatus 3 by the process of S616 is received by the process of S503 (see FIG. 11) of the communication terminal apparatus 3. Next, it is determined whether or not the video conference is ended (S617). If the video conference has not ended (S617: NO), the process returns to S615 and is repeated. That is, encoding processing is performed until the video conference is terminated (S615), and the connected terminal encoded data is transmitted to the communication terminal device 3 (S616). When the video conference is terminated (S617: YES), the second main process by the connected terminal is terminated.

  As described above, the first main process of the communication terminal device 3 and the second main process of the connection terminal are performed.

  Next, a case where the data encoded by each terminal stored in the encoded data storage area 314 is decoded and reproduced will be described. Here, in the video conference system 1 shown in FIG. 1, it is assumed that the communication terminal device 3 and the connection terminals 4 and 5 are performing a video conference. Then, a case will be described in which a connection terminal 6 is newly connected to the network 2 as shown in FIG. In the connection terminal 6, the communication terminal device 3 and the connection terminals 4 and 5 have the same electrical configuration, and the same software is set.

  Since the user using the connection terminal 6 participates in the conference from the middle, the content of the conference held before the connection terminal 6 is connected to the network 2 is not known. Therefore, the user using the connection terminal 6 acquires the data (hereinafter referred to as “recording data”) encoded by each terminal stored in the encoded data storage area 314 of the communication terminal device 3. By playing on the connection terminal 6, the contents of the conference can be known. Here, for explanation, it is assumed that the recorded data is data recorded in the case of the first specific example shown in FIG. The connection terminal 6 is connected during the conference, that is, the connection terminal 6 is connected while the communication terminal device 3 is performing the recording process (see FIG. 11). The third main process (see FIG. 17) executed in the connection terminal 6 described below and the fourth main process (see FIG. 18) executed in the communication terminal apparatus 3 are the recording process (see FIG. 11). That is, the communication terminal device 3 can perform the fourth main process while executing the recording process. The third main process and the fourth main process can also be performed after the first main process (see FIG. 6) of the communication terminal device 3 is completed.

  First, the third main process executed in the connection terminal 6 will be described with reference to the flowchart shown in FIG. In the third main process shown in FIG. 17, first, a transmission request for the I picture encoding cycle and the recording start time is made to the communication terminal apparatus 3 (S801). Next, it is determined whether or not the I picture encoding cycle and the recording start time transmitted from the communication terminal device 3 to the connection terminal 6 have been received (S802). The transmission request of the I picture encoding cycle and the recording start time transmitted by the processing of S801 is received in the processing of S901 (see FIG. 18) of the communication terminal device 3 described later. Then, the I picture encoding cycle and the recording start time are transmitted from the communication terminal device 3 (S902 in FIG. 18, which will be described later). In the process of S802, it is determined whether or not the I picture encoding cycle and the recording start time transmitted by the process of S902 of the communication terminal apparatus 3 are received. If the I picture encoding cycle and the recording start time transmitted by the process of S902 of the communication terminal device 3 are not received (S802: NO), then the process returns to S802 and the process is repeated. That is, it waits until the I picture encoding cycle and the recording start time transmitted by the processing of S902 of the communication terminal device 3 are received.

  When the I picture encoding cycle and the recording start time transmitted by the processing of S902 of the communication terminal device 3 are received (S802: YES), it is subsequently determined whether or not the cue mode has been selected by the user. It is determined (S803). The cueing mode is a mode in which the user designates time and playback is started from the time designated by the user. The user can select the cueing mode by operating the mouse 27 or the keyboard 29 (see FIG. 2). When selecting the cueing mode, the user inputs a time at which playback is to be started (hereinafter referred to as “playback start time”).

  If the cueing mode has not been selected (S803: NO), it is then determined whether or not the fast-forward mode has been selected (S804). The fast-forward mode is a mode in which recorded data is played back in fast-forward. The user can select the fast-forward mode by operating the mouse 27 or the keyboard 29 (see FIG. 2). When selecting the fast-forward mode, the user selects a fast-forward speed divided into several speeds.

  If the fast-forward mode is not selected (S804: NO), then, the first request which is data requesting the communication terminal device 3 to sequentially transmit all the pictures included in the recorded data. Data is transmitted (S805). Next, it is determined whether or not the recording data transmitted from the communication terminal device 3 has been received (S806). The first request data transmitted to the communication terminal apparatus 3 by the process of S805 is received in the process of S903 of the communication terminal apparatus 3 (see FIG. 18), and the process of S904 is performed based on the first request data. Thus, all the pictures included in the recorded data are transmitted to the connection terminal 6 in order. In the process of S806, it is determined whether the recording data transmitted by the process of S904 of the communication terminal device 3 has been received. If no recorded data has been received (S806: NO), the process returns to S806 and the process is repeated. That is, the connection terminal 6 stands by until recording data transmitted from the communication terminal device 3 is received. When the recording data transmitted from the communication terminal device 3 is received (S806: YES), the recording data received in the process of S806 is subsequently decoded and an image is displayed on the display 28 (see FIG. 2). (S807). The recording data is decoded by the decoder 37. Next, it is determined whether or not the last picture in the recorded data has been received (S808).

  If the last picture has not been received (S808: NO), then the process returns to S803 and the process is repeated. That is, when the cue mode is not selected (S803: NO), the fast-forward mode is not selected (S804: NO), and the last picture in the recorded data is not received (S808: NO), the first request Data is transmitted (S805), pictures are received in order (S806: YES), and images are displayed in order on the display 28 (S808). As a result, normal reproduction is performed.

  If the last picture has been received (S808: YES), the third main process in the communication terminal device 3 is terminated.

  In the case of the first specific example, it is assumed that the recording start time is 12:00. Accordingly, the recording start time “12:00” and the I picture encoding period “400 ms” are received by the processing of S802. Then, when the cue mode is not selected (S803: NO), the fast-forward mode is not selected (S804: NO), and the last picture in the recorded data is not received (S808: NO), FIG. All the pictures of the communication terminal device 3 shown and the connecting terminals 4 and 5 are received in order (S806). Then, all pictures of the communication terminal device 3 and the connection terminals 4 and 5 received in S806 are decoded and an image is displayed on the display 28. As a result, normal reproduction is performed.

  When the cue mode is selected (S803: YES), the reproduction start time is acquired (S809). As described above, when selecting the cueing mode, the user inputs the reproduction start time. In the process of S809, the reproduction start time input by the user is acquired. Next, the position of the common I picture closest to the playback start time among the common I pictures included in the recorded data is specified (S810). Next, second request data, which is data for requesting transmission of recording data starting from the I picture at the position specified by the processing of S810, is transmitted to the communication terminal device 3 (S811). Next, the process proceeds to S806, where it is determined whether or not the recording data transmitted from the communication terminal device 3 has been received. The second request data transmitted to the communication terminal apparatus 3 by the process of S811 is received by the process of S903 (see FIG. 18) of the communication terminal apparatus 3. Then, based on the second request data, the recording data starting from the common I picture at the position specified by the processing of S810 is transmitted to the connection terminal 6 (S904). Then, it is received by the process of S806, decoded and displayed on the display 28 (S807). Thereby, cue playback is performed. Next, when the last picture in the recorded data has not been received (S808: NO), the process returns to S803 and is repeated.

  In the case of the first specific example, when the cueing mode is selected (S803: YES), the reproduction start time is acquired (S809). The recording start time received in the process of S802 is “12:00”. Further, it is assumed that the reproduction start time input by the user is “12:20”. That is, it is assumed that the reproduction start time is 1200 seconds after the start of recording. Through the process of S809, “12:20” which is the reproduction start time input by the user is acquired. Then, the I picture encoding period received in the processing of S802 is 400 ms, and is 0.4 seconds. Therefore, among the common I pictures included in the recorded data, the common I picture closest to the reproduction start time “1200 seconds” is identified as the common I picture encoded after “1200 seconds” from the start of recording. (S810). Next, second request data, which is data for requesting transmission of recording data starting from a common I picture that is “1200 seconds” after the start of recording, is transmitted to the communication terminal device 3 (S811). The second request data transmitted to the communication terminal apparatus 3 by the process of S811 is received by the process of S903 (see FIG. 18) of the communication terminal apparatus 3. Based on the second request data, the recording data starting from the common I picture “1200 seconds” after the start of recording is transmitted to the connection terminal 6 (S904). Then, it is received by the process of S806, decoded and displayed on the display 28 (S807). As a result, cue playback is performed. Next, when the last picture in the recorded data has not been received (S808: NO), the process returns to S803 and is repeated.

  If the fast-forward mode is selected (S804: YES), then the fast-forward speed is recognized (S812). As described above, when selecting the fast-forward mode, the user selects a fast-forward speed divided into several speeds. In the process of S812, the fast-forward speed selected by the user is recognized. Then, among the fast-forwarding speeds divided into several speeds, the fast-forwarding speed selected by the user is set as a variable “M” (S812). For example, when the user selects the second speed from the slow speeds among the fast-forward speeds divided into five speeds, “M = 2” is recognized by the process of S812. Next, third request data, which is data requesting to transmit “M−1” skipped common I pictures in the recorded data, is transmitted to the communication terminal device 3 (S813). Next, the process proceeds to S806, where it is determined whether or not the recording data transmitted from the communication terminal device 3 has been received. The third request data transmitted to the communication terminal apparatus 3 by the process of S813 is received by the process of S903 (see FIG. 18) of the communication terminal apparatus 3. Then, the communication terminal device 3 transmits “M−1” skipped common I pictures in the recorded data based on the third request data (S904). Then, it is received by the process of S806, decoded and displayed on the display 28 (S807). Next, when the last picture in the recorded data has not been received (S808: NO), the process returns to S803 and is repeated. Thereby, fast-forwarding is performed.

  In the case of the first specific example, when the fast-forward mode is selected (S804: YES), the fast-forward speed is recognized (S812). Here, it is assumed that the fast-forward speed is divided into 10 stages. Further, it is assumed that the fast-forward speed selected by the user is the third speed from the slow speed. In this case, “M = 3” is recognized by the processing of S812. Next, third request data, which is data requesting transmission of “M−1” skipped common I pictures (that is, skipping two), is transmitted to the communication terminal device 3 in the recorded data ( S813). Since the I picture encoding period is 400 ms, a common I picture is generated every 400 ms (see FIG. 12). In the process of S813, a request is made to transmit a common I picture by skipping two. That is, a request is made to transmit a common I picture generated every 1200 ms. The third request data transmitted to the communication terminal apparatus 3 by the process of S813 is received by the process of S903 (see FIG. 18) of the communication terminal apparatus 3. Based on the third request data, two common I pictures are skipped and transmitted to the connecting terminal 6 (S904). Then, it is received by the process of S806, decoded and displayed on the display 28 (S807). Next, when the last picture in the recorded data has not been received (S808: NO), the process returns to S803 and is repeated. As a result, only an image every 1200 ms is displayed on the display 28. That is, it is fast forwarded.

  Next, with reference to the flowchart shown in FIG. 18, the 4th main process performed in the communication terminal device 3 is demonstrated.

  In the fourth main process shown in FIG. 18, first, it is determined whether or not a transmission request for the I picture encoding period and the recording start time transmitted by the process of S801 of the connection terminal 6 (see FIG. 17) has been received. (S901). If a transmission request for the I picture encoding cycle and the recording start time has not been received (S901: NO), the process returns to S901 and is repeated. That is, the communication terminal device 3 is on standby. When a transmission request for the I picture encoding cycle and the recording start time is received (S901: YES), the I picture encoding cycle and the recording start time are subsequently transmitted to the connection terminal 6 (S902). . In the processing of S <b> 902, the I picture coding cycle stored in the I picture coding cycle storage area 313 is transmitted to the connection terminal 6. The recording start time is referred to from the recording data stored in the encoded data storage area 314, and the recording start time is transmitted to the connection terminal 6 (S902).

  Next, it is determined whether the first request data, the second request data, or the third request data transmitted from the connection terminal 6 has been received (S903). If the first request data, the second request data, or the third request data has not been received (S903: NO), the process returns to S903 and is repeated. That is, the communication terminal device 3 is on standby. When the first request data, the second request data, or the third request data is received (S903: YES), subsequently, based on the first request data, the second request data, or the third request data, The recorded data is transmitted to the connection terminal 6 (S904). The process of S904 corresponds to the first request data, the second request data, or the third request data received in the process of S903 out of the recorded data stored in the encoded data storage area 314 (see FIG. 3). The read picture is read out and transmitted to the connection terminal 6. More specifically, when the first request data is received, all the pictures included in the recording data are sequentially transmitted to the connection terminal 6 (S904). That is, the recording data for the connection terminal 6 to perform normal reproduction is transmitted. When the second request data is received, the recording data starting from the common I picture at the position specified by the processing of S810 (see FIG. 17) of the connecting terminal 6 is transmitted to the connecting terminal 6 (S904). That is, the connected terminal 6 transmits recording data including a common I picture for performing cueing reproduction. When the third request data is received, “M−1” common I pictures are skipped from the recorded data (S905). That is, the common I picture for the connection terminal 6 to perform fast forwarding is transmitted to the connection terminal 6.

  Next, it is determined whether or not the last picture in the recorded data has been transmitted to the connection terminal 6 (S905). If the last picture in the recorded data has not been transmitted to the connected terminal 6 (S905: NO). Subsequently, the process returns to S903 and is repeated. That is, recording data is continuously transmitted based on the first request data, the second request data, or the third request data transmitted from the connection terminal 6.

  When the last picture in the recorded data is transmitted to the connection terminal 6 (S905: YES), the fourth main process in the communication terminal device 3 is ended.

  In the third main process and the fourth main process, audio data stored in the encoded data storage area 314 is also transmitted and received. As a result, when normal playback is performed on the connection terminal 6, the audio is played back at a normal speed. When fast-forwarding, the sound is reproduced at a speed corresponding to the fast-forwarding speed of the image. In the case of cueing, sound is reproduced from a position corresponding to the cueed image.

  As described above, the processing of the communication terminal device 3 and the connection terminal in the first embodiment is performed. As described above, the I picture is data that can restore an image by referring only to information included in the I picture, and does not require a reference picture. On the other hand, a P picture and a B picture require a reference picture. In the present embodiment, the I picture encoding period is determined so that the communication terminal apparatus 3 and the connection terminals 4 and 5 can encode an image based on the common I picture encoding period. This makes it possible to synchronize the timing at which the communication terminal device 3 and the connection terminals 4 and 5 encode an image as an I picture. Then, when the connection terminal 6 is connected to the network 2 during the video conference and fast-forwarding is performed, the common I picture is transferred from the communication terminal device 3 to the connection terminal 6 according to the third request data from the connection terminal 6. Transmit (S904 in FIG. 18). Since only the I picture is transmitted, there is no need to transmit the reference picture. That is, the amount of data is reduced as compared with the case of transmitting a P picture or B picture and a reference picture, so that the load on the network 2 can be reduced. Even in the case of performing the cue reproduction, the recording data starting from the common I picture is transmitted from the communication terminal device 3 to the connection terminal 6. Therefore, the amount of data can be reduced and the load on the network 2 can be reduced as compared with the case where recording data starting from a P picture or B picture is transmitted.

  Further, as described above, the I picture encoding period and the changed image display time are calculated by the image display time change process (see FIG. 8). The second target value is set by the processing of S301 to S305. At this time, the number of all terminals connected to the network 2 is set to the variable N (S302). When the value of the variable N is as large as possible and there is a least common multiple that is equal to or less than the first threshold, the iterative process of S302 to S304 is terminated. Thereby, it is not necessary to calculate the changed image display time by performing the processing of S307 to S310 for the image display time of N terminals among the terminals connected to the network 2. That is, it is not necessary to change the image display time of as many terminals as possible. For this reason, the I picture encoding cycle can be determined without changing the frame rate of a large number of terminals.

  In this embodiment, the I picture encoding cycle is set to be equal to or less than the first threshold (see FIGS. 7 and 8). For this reason, if the first threshold value is set so that the I picture encoding period becomes an appropriate period, the I picture encoding period can be set at an appropriate period.

  In this embodiment, the I picture encoding cycle is set to be close to the first target value. For this reason, the I picture encoding cycle can be set at an appropriate cycle.

  Further, in the present embodiment, it is determined whether or not the I picture coding cycle of the connected terminal matches the I picture coding cycle determined by the coding cycle determination process shown in FIG. 7 (FIG. 10). S403). If they do not match, the I picture encoding period determined by the encoding period determination process is retransmitted to the connected terminal (S118 in FIG. 6), so that the I picture encoding period of the connected terminal is more reliably determined. It can be made to coincide with the I picture coding cycle determined by the coding cycle determination process.

  In the present embodiment, when the changed frame rate is transmitted to the connecting terminal (S115 in FIG. 6), it is determined whether or not the changed frame rate is appropriately set in the connecting terminal (S403 in FIG. 10). ). If they do not match, the changed frame rate is retransmitted to the connected terminal (S118 in FIG. 6), so that the frame rate of the connected terminal can be more reliably changed to the changed frame rate.

  Further, in this embodiment, connection terminal encoded data encoded by the connection terminal is received (S503 in FIG. 11). Then, the connection terminal encoded data and the communication terminal encoded data can be stored in the encoded data storage area 314 (S502 and S505 in FIG. 11). That is, image data encoded by all terminals can be stored in one storage device. Thereby, the state of the video conference can be recorded in one storage device.

  Further, the communication terminal device 3 of the present embodiment can select a common I picture from the recorded data in response to a request from the connection terminal 6 and transmit an appropriate common I picture to the connection terminal (FIG. 18). S904).

  Further, as described above, in the present embodiment, the communication terminal device 3 and the connection terminals 4, 5, 6 have the same electrical configuration, and the same software is set. That is, any one of all terminals connected to the network 2 can function as a communication terminal device. Also, other terminals can function as connection terminals.

  Note that the communication terminal device 3 and the connection terminal of the present invention are not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

  For example, the communication terminal device 3 and the connection terminals 4, 5, 6 have the same electrical configuration and the same software is set, but the present invention is not limited to this. For example, the communication terminal device 3 may be a terminal that is configured only with an electrical configuration necessary for operating as a communication terminal device and in which only processing necessary for operating as a communication terminal device is set. Further, the connection terminals 4, 5, and 6 may be terminals that are configured only with an electrical configuration necessary for operating as a connection terminal and in which only processing necessary for operating as a connection terminal is set.

  Further, when the least common multiple of the image display times of all the terminals is not equal to or less than the first threshold (S207: NO in FIG. 7), the image display time changing process (S211 in FIG. 7) has been executed. Not. For example, if the least common multiple of at least two image display times is not less than or equal to the first threshold value, the image display time changing process may be performed. This is because if the least common multiple of the image display times of at least two is larger than the first threshold, it is determined that the least common multiple of the image display times of all terminals is larger than the first threshold. For example, when three terminals are connected to the network 2, if the least common multiple of two of the three terminals is calculated and is greater than the first threshold, the least common multiple including the remaining one is calculated. Even if not, it is determined that the least common multiple of all three units is equal to or greater than the first threshold. For this reason, it is not necessary to calculate the least common multiple including the remaining one. For this reason, the frequency | count of the process of S203-S206 can be reduced. In order to realize this, for example, the processing of S207 in FIG. 7 may be moved between the processing of S205 and the processing of S206, and the processing of S207 may be executed after the processing of S205. In this case, when the variable t is not less than or equal to the first threshold (S207: NO), next, an image display change process (S211) is executed, and when the variable t is less than or equal to the first threshold (S207: YES), Next, the process of S206 is executed. If all terminals have been selected (S206: YES), then the process of S208 is executed. In this way, when the calculated variable t becomes equal to or greater than the first threshold value in the process of S205 (S207: YES), the image display change process of S211 is executed. That is, the image display time change process is performed even when the variable t is equal to or greater than the first threshold before calculating the least common multiple of the image display times of all the terminals.

  17 and 18 illustrate only cue playback, fast forward, and normal playback, but the present invention is not limited to this. For example, rewinding may be performed. Even when rewinding is performed, the load on the network 2 can be reduced by transmitting only the common I picture.

  In addition, the recorded data is stored in the HDD 31 of the communication terminal device 3, but the present invention is not limited to this. For example, each terminal may store image data encoded by itself in the HDD 31 of its own terminal. Then, the connection terminal 6 may receive image data stored in the HDD 31 of each terminal and execute reproduction, fast-forward, or the like.

  In addition, the recorded data is stored in the encoded data storage area 314 of the HDD 31, but the present invention is not limited to this. For example, an external storage device 7 may be provided and connected to the network 2 as shown in FIG. Then, the communication terminal encoded data and the connection terminal encoded data may be stored in the external storage device 7 by the processes of S502 and S505 of FIG. Thereby, the recording data can be stored in the external storage device 7.

  Further, the communication terminal device 3 may not receive the connection terminal encoded data. For example, the communication terminal device 3 and the connection terminals 4 and 5 individually access the external storage device 7 (see FIG. 19), and the communication terminal encoded data and the connection terminal encoded data are directly stored in the external storage device 7. You may let them. Further, the I picture encoding cycle and the like may be stored in the external storage device 7.

  Alternatively, the connection terminal 6 may directly access the external storage device 7 and receive the recording data without going through the communication terminal device 3.

  In the above embodiment, the camera 34 corresponds to “image input means”. Further, the frame rate of the connected terminal received by the process of S104 of FIG. 6 corresponds to the “first frame rate” of the present invention, and the CPU 20 that performs the process of S104 of FIG. It corresponds to. Further, the CPU 20 that performs the process of S107 in FIG. 6 corresponds to the “encoding period determining unit” of the present invention, and the CPU 20 that performs the process of S111 of FIG. 6 corresponds to the “encoding period transmitting unit” of the present invention. The communication terminal encoded data corresponds to the “first encoded information” of the present invention, and the CPU 20 that performs the process of S501 in FIG. 11 corresponds to the “first encoding means” of the present invention. The HDD 31 and the external storage device 7 correspond to the “first storage device” of the present invention, and the CPU 20 that performs the processing of S502 of FIG. 11 and the processing of S505 of FIG. 11 “encoded information storage means” of the present invention. It corresponds to.

  Further, the CPU 20 that performs the process of S201 in FIG. 7 corresponds to the “display time calculating means” of the present invention, and the CPU 20 that performs the processes of S210 and S212 in FIG. 7 corresponds to the “first period determining means” of the present invention. . 7 corresponds to the “first calculation unit” of the present invention, and the least common multiple calculated by the process of S204 in FIG. 7 corresponds to “first least common multiple”. Further, the CPU 20 that performs the process of S207 in FIG. 7 corresponds to the “first determination unit” of the present invention, and the CPU 20 that performs the process of S211 of FIG. 7 corresponds to the “change time calculation unit” of the present invention. Further, the second target value corresponds to the “second least common multiple” of the present invention, and the CPU 20 that performs the process of S212 in FIG. 7 corresponds to the “second period determining means” of the present invention. Further, the CPU 20 that performs the process of “YES” in S108 of FIG. 6, the process of S114, and the process of S115 corresponds to the “frame rate change instruction unit” of the present invention. Further, the CPU 20 that performs the process of S109 in FIG. 6 corresponds to the “first frame rate changing unit” of the present invention, and the CPU 20 that performs the process of S402 of FIG. 10 corresponds to the “encoding period acquisition unit” of the present invention. The CPU 20 that performs the process of S403 in FIG. 10 corresponds to the “second determination unit” of the present invention. Further, the CPU 20 that performs the process of S118 in FIG. 6 corresponds to the “second encoding cycle transmitting unit” of the present invention, and the CPU 20 that performs the process of S503 in FIG. 11 corresponds to the “encoded information receiving unit” of the present invention. To do.

  The connection terminal encoded data corresponds to the “second encoded information” of the present invention. Further, the common I picture corresponds to “I picture encoded information” of the present invention, and the CPU 20 that performs the processing of S904 in FIG. 18 corresponds to “encoded information transmitting means” of the present invention. Further, the CPU 20 that performs the process of S604 in FIG. 14 corresponds to the “encoding period receiving unit” of the present invention, and the CPU 20 that performs the process of S615 of FIG. 14 corresponds to the “second encoding unit” of the present invention. Further, the CPU 20 that performs the process of S616 in FIG. 14 corresponds to the “encoded information transmitting unit” of the present invention.

  6 corresponds to the “frame rate acquisition step” of the present invention, and the process of S107 of FIG. 6 corresponds to the “coding cycle determination step” of the present invention. 6 corresponds to the “encoding cycle transmission step” of the present invention, and the process of S501 of FIG. 11 corresponds to the “first encoding step” of the present invention. Further, the process of S502 of FIG. 11 corresponds to the “encoded information storing step” of the present invention.

DESCRIPTION OF SYMBOLS 1 Video conference system 2 Network 3 Communication terminal device 4 Connection terminal 5 Connection terminal 6 Connection terminal 7 External storage device 20 CPU
22 RAM
28 Display 31 HDD
34 Camera 36 Encoder 37 Decoder 38 Timer 227 Change display time storage area 311 Program storage area 312 Own terminal frame rate storage area 313 I-picture encoding cycle storage area 314 Encoded data storage area

Claims (10)

An image input by an image input means connected to a network is encoded, and encoded information, which is information obtained by encoding the image, is exchanged with a connection terminal that is another terminal connected via the network. A communication terminal device for transmitting and receiving,
Frame rate acquisition means for acquiring a first frame rate that is a frame rate of the connection terminal connected to the network;
Based on the first frame rate acquired by the frame rate acquisition means and the second frame rate, which is the frame rate of the communication terminal device, an I picture encoding cycle that is a cycle for encoding the image as an I picture Encoding period determining means for determining
Encoding period transmitting means for transmitting the I picture encoding period determined by the encoding period determining means to the connected terminal;
First encoding means for creating first encoded information, which is information obtained by encoding the image, based on the I picture encoding period determined by the encoding period determining means;
A communication terminal device comprising: encoded information storage means for storing the first encoded information created by the first encoding means in a first storage device that is a device for storing data. The encoding period determining means includes
From the first frame rate and the second frame rate acquired by the frame rate acquisition means, an image display time which is a time for displaying one image on the image display means for displaying an image is set as the connection terminal. Display time calculating means for calculating each of the communication terminal devices;
One of at least two common multiples of the image display time among the image display time of the connection terminal and the image display time of the communication terminal device calculated by the display time calculation means is the I The communication terminal apparatus according to claim 1, further comprising first period determining means for setting a picture encoding period. The encoding period determining means includes
The first least common multiple which is the time of the least common multiple of the image display time of at least two of the image display time of the connection terminal and the image display time of the communication terminal device calculated by the display time calculation means. First calculating means for calculating
First determination means for determining whether the first least common multiple calculated by the first calculation means is equal to or less than a first threshold;
When the first determination unit determines that the first least common multiple is not less than or equal to the first threshold, the image display time of the connection terminal calculated by the display time calculation unit and the image of the communication terminal device A second least common multiple which is a least common multiple of a changed image display time which is an image display time obtained by changing at least one of the image display times and a display time other than the changed image display time. Change time calculation means for calculating the change image display time so as to be equal to or less than a threshold;
A second period determining means that uses the second least common multiple as the I picture encoding period,
The communication terminal device
The frame rate is changed so that the image display time becomes the changed image display time for the connection terminal or the communication terminal device whose image display time has been changed to the changed image display time by the change time calculation means. Frame rate change instruction means for instructing to perform,
First frame rate changing means for changing the first frame rate of the communication terminal apparatus when the communication terminal apparatus is instructed to change the first frame rate by the frame rate change instruction means; The communication terminal device according to claim 2, further comprising: Coding cycle acquisition means for acquiring the I picture encoding cycle of the connection terminal;
Second judging means for judging whether or not the I picture coding period of the connected terminal obtained by the coding period obtaining means coincides with the I picture coding period determined by the coding period determining means. When,
The second determining means determines that the I picture encoding period of the connected terminal acquired by the encoding period acquiring means does not match the I picture encoding period determined by the encoding period determining means. A second encoding period transmitting means for retransmitting the I picture encoding period determined by the encoding period determining means to the connection terminal determined that the I picture encoding periods do not match. The communication terminal apparatus according to claim 1, further comprising: Coding encoded by the connecting terminal according to the I picture coding period transmitted by the coding period transmitting means and receiving second coding information as the coding information transmitted from the connecting terminal Further comprising information receiving means,
The encoded information storage means includes
The first storage device stores the first encoded information created by the first encoding unit and the second encoded information received by the encoded information receiving unit. Item 5. The communication terminal device according to any one of Items 1 to 4.   In response to a request from the connection terminal, the first encoded information stored in the first storage device by the encoded information storage means is encoded as the I picture based on the I picture encoding period. 5. The encoding information transmitting unit according to claim 1, further comprising: encoding information transmitting means for selecting I picture encoded information which is information of the image and transmitting the I picture encoded information to the connected terminal. The communication terminal device according to claim 1.   Based on the I picture encoding period from the first encoded information and the second encoded information stored in the first storage device by the encoded information storage means in response to a request from the connection terminal And encoding information transmitting means for selecting I picture encoded information which is information of the image encoded as the I picture and transmitting the I picture encoded information to the connection terminal. The communication terminal device according to claim 5. Encoding period receiving means for receiving the I picture encoding period transmitted by the encoding period transmitting means of another communication terminal device connected to the network;
Second encoding means for creating the second encoded information based on the I picture encoding period received by the encoding period receiving means;
The communication terminal according to claim 5 or 7, further comprising encoded information transmission means for transmitting the second encoded information created by the second encoding means to the other communication terminal apparatus. apparatus. An image input by an image input means connected to a network is encoded, and encoded information, which is information obtained by encoding the image, is exchanged with a connection terminal that is another terminal connected via the network. A terminal control method executed in a communication terminal device for transmitting and receiving,
A frame rate acquisition step of acquiring a first frame rate that is a frame rate of the connection terminal connected to the network;
Based on the first frame rate acquired by the frame rate acquisition step and the second frame rate, which is the frame rate of the communication terminal apparatus, an I picture encoding cycle that is a cycle for encoding the image as an I picture A coding period determining step for determining
A coding cycle transmission step of transmitting the I picture coding cycle determined by the coding cycle determination step to the connecting terminal;
A first encoding step of creating first encoding information that is information obtained by encoding the image based on the I picture encoding period determined by the encoding period determining step;
A terminal control method comprising: an encoded information storage step of storing the first encoded information created by the first encoding means in a first storage device that is a device for storing data. An image input by an image input means connected to a network is encoded, and encoded information, which is information obtained by encoding the image, is exchanged with a connection terminal that is another terminal connected via the network. A terminal control program executed in a communication terminal device for transmitting and receiving,
On the computer,
A frame rate acquisition step of acquiring a first frame rate that is a frame rate of the connection terminal connected to the network;
Based on the first frame rate acquired by the frame rate acquisition step and the second frame rate, which is the frame rate of the communication terminal apparatus, an I picture encoding cycle that is a cycle for encoding the image as an I picture A coding period determining step for determining
A coding cycle transmission step of transmitting the I picture coding cycle determined by the coding cycle determination step to the connecting terminal;
A first encoding step of creating first encoding information that is information obtained by encoding the image based on the I picture encoding period determined by the encoding period determining step;
A terminal control program that causes the first encoded information created by the first encoding means to be stored in a first storage device that is a device for storing data.

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