WO2012043290A1

WO2012043290A1 - Video call system, main-side terminal, and subordinate-side terminals

Info

Publication number: WO2012043290A1
Application number: PCT/JP2011/071306
Authority: WO
Inventors: 和田　真; 田中　克明; 大野　博; 潤山形; 哲夫楠
Original assignee: コクヨ株式会社
Priority date: 2010-09-30
Filing date: 2011-09-20
Publication date: 2012-04-05
Also published as: TW201220847A; JP2012080186A

Abstract

A main-side terminal (11), when starting a video call, refers to allowed bandwidth information for each of terminals (11 and 12), and calculates a value which is the allowed transfer rate divided by the number of subordinate-side terminals (12) as the maximum value of the transfer rate for video image data to be transmitted from each of the terminals (11 and 12) during the video call. Then, information of the calculated maximum transfer rate is transmitted from the main-side terminal (11) toward each of the subordinate-side terminals (12).

Description

Video call system, master terminal, slave terminal

The present invention relates to a system for realizing a video call function in which three or more parties can participate.

Video call systems that realize video lectures or video conferences between multiple points via telecommunications lines are well known.

Recently, the demand for higher-quality video has been increasing, but the bandwidth of the communication line is still a bottleneck, and more than three people send high-quality video to each. If you try to do so, the communication bandwidth will be insufficient immediately. If the communication bandwidth is insufficient, video frames are dropped and audio is interrupted, making it no longer suitable for lectures and meetings on important topics.

In order to avoid this, a guarantee-type (non-best-effort type) dedicated line with a sufficiently high communication speed is installed, or an MCU (Multi-point Control) that is a high-performance relay device between each base. It is effective to use a unit). However, there is no denying that all of them require huge investments. Although it may be possible to use IP (Internet Protocol) multicast technology, at present, it is not generally allowed to perform multicast communication on a public line such as the Internet.

In view of the above, the applicant has proposed a new video call system that enables high-quality video to be exchanged with a relatively inexpensive investment (see the following patent documents and non-patent documents).

By the way, an off-the-shelf system automatically optimizes the transfer rate of video data to be transmitted in response to the congestion status of the line that varies depending on the day or time. However, it takes a certain amount of time to optimize the transfer rate of the video data, and although the video sent from the other party is waited until it is displayed on the screen or displayed, the video is not stable. May cause problems.

Japanese Patent Application No. 2009-170612

The main object of the present invention is to stabilize the video display as much as possible immediately after the start of a video call in which there are three or more participants.

The present invention is a system for realizing a video call function for transmitting and receiving video between terminals installed at each of three or more bases, and any one terminal is a master terminal and the remaining terminals are slave terminals. The data transfer rate (uplink rate) that can be transmitted via the communication line connected to the terminal for each terminal when the main terminal starts a video call or data that can be received The maximum transfer rate that should be transmitted during video calls from each terminal to other terminals by referring to the transfer rate (downlink rate) and discounting the transfer rate according to the number of slave terminals A maximum rate calculation unit that calculates a value, a maximum rate specification information transmission unit that transmits maximum rate specification information describing the calculated maximum transfer rate to each of the slave terminals, and the master side terminal A call transmission unit that generates video data having a rate equal to or less than the calculated maximum transfer rate from video captured by the camera at the installation site of the mobile station and transmits the video data to each of the slave terminals, and is transmitted from each of the slave terminals. And a call output control unit for displaying the received video data on the display screen, and the slave terminal transmits a maximum of the maximum number of messages transmitted from the master terminal at the start of the video call. Generates video data at a rate equal to or less than the maximum transfer rate described in the maximum rate specification information from the maximum rate specification information receiving unit that receives the rate specification information and the video captured by the camera at the location where the slave terminal is installed. A call transmitting unit for transmitting to each of the main terminal and other slave terminals, and a call for receiving video data transmitted from each of the master terminal and other slave terminals. A signal unit and the received video data to configure a video call system characterized in that it comprises a call output control unit for displaying on the display screens.

The maximum rate calculation unit of the master terminal basically calculates the maximum transfer rate by dividing the transfer rate by the number of slave terminals.

In addition, a group view mode in which video data is transmitted from all terminals to each of the other terminals, and all the terminals display and output videos of all bases other than their own base, and each of the slave terminals from the master terminal It is good also as a system which can switch arbitrarily to the single view mode which transmits video data with respect to, and the slave side terminal displays and outputs the video of the installation base of the master side terminal. In this case, the main terminal switches an operation input receiving unit that receives an operation input indicating that the group view mode and the single view mode should be switched, and switches between the group view mode and the single view mode in response to the received operation input. And a command transmission unit that transmits a switching command, which is a command for the slave terminal, to each of the slave terminals, and the call transmission unit is not restricted to the maximum transfer rate in the single view mode. Video data having a higher transfer rate than the mode is generated and transmitted to each of the slave terminals, and the slave terminal further includes a command receiving unit that receives a switching command transmitted from the master terminal. In addition, in the single view mode, the call transmission unit transmits video data only to the main terminal, and the call reception unit It shall only receive video data from the main terminal in the single view mode. In reality, in video lectures and video conferences, not all participants need images of all other participants at all times. Therefore, in the single view mode, transmission / reception of video between the slave terminals is stopped, and higher-quality video with an increased transfer rate can be distributed from the master terminal to each slave terminal. .

In the single view mode, it is also preferable to be able to change a terminal that sends high-quality video to other terminals, that is, a subject that attracts the attention of others in a video call. That is, from all terminals, the video data is transmitted to each of the other terminals, and all the terminals display and output the video of all bases other than their own base, and from any one selected terminal It is possible to switch to a single view mode that transmits video data to each of the other terminals and displays and outputs the video of the installation base of the one terminal selected by the other terminal, the main terminal Corresponding to the operation input accepting an operation input for switching between the group view mode and the single view mode and an operation input for selecting any one terminal in the single view mode, Command to switch between group view mode and single view mode, or which terminal is selected in single view mode A command transmission unit that transmits a switching command that is a command for the slave terminal to each of the slave terminals, and the call transmitter is in a single view mode and the master terminal itself is selected Is not restricted by the maximum transfer rate and generates video data having a higher transfer rate than other cases and transmits it to each of the slave terminals, while the single view mode and slave terminal are selected. Video data is transmitted only to the selected terminal, and when the call receiver is in single view mode and the slave terminal is selected, the video is transmitted only from the selected terminal. In addition to transmitting data, the slave terminal further includes a command receiving unit that receives a switching command transmitted from the master terminal. When the side terminal itself is selected, it generates video data having a higher transfer rate than the other cases without being constrained by the maximum transfer rate to each of the master side terminal and the other slave side terminals. On the other hand, when the single-view mode and the master terminal or other slave terminal are selected, the video data is transmitted only to the selected terminal, and the call receiver Mode, and when a master terminal or other slave terminal is selected, if the system receives video data only from the selected terminal, a terminal other than the master terminal is selected in the single view mode. Thus, it is possible to distribute high-quality video from the terminal toward other terminals including the main terminal. That is, it is possible to appropriately change the subject that attracts the attention of others in the video call by the hand of the user who operates the main terminal.

Further, the operation input receiving unit of the master side terminal should operate the pan, tilt, or zoom of the camera associated with the slave terminal when the single view mode and another slave terminal are selected. An operation input is received, and the command transmission unit of the master terminal transmits a camera operation command for operating the pan, tilt, or zoom of the camera to the selected slave terminal in response to the received operation input. If the command receiving unit of the slave terminal is a system that receives a camera operation command transmitted from the master terminal when the slave terminal itself is selected in the single view mode, any slave In a situation where high-definition video is being distributed from the side terminal to the master side terminal and other slave side terminals, the user of the master side terminal can remotely control the camera of the slave side terminal as necessary. Can.

If the main terminal also has the function as the slave terminal, the master terminal and the slave terminal can be shared, which contributes to a reduction in the production cost of the terminal.

According to the present invention, the video display can be stabilized as much as possible immediately after the start of a video call in which three or more participants exist.

The figure which shows the outline | summary of the video call system of one Embodiment of this invention. The figure which shows the hardware resource which the terminal in the embodiment comprises. Functional block diagram of the terminal. Functional block diagram of the terminal. The figure explaining the content of the group view mode in this embodiment. The figure explaining the content of the single view mode in this embodiment. The figure explaining the content of the single view mode in this embodiment. The figure which illustrates the information memorize | stored and accumulated in the telephone directory memory | storage part. The figure which shows the example of a screen display on a terminal. The figure which shows the example of a screen display on a terminal. The flowchart which shows the procedure of the process which a terminal performs according to a program. The flowchart which shows the procedure of the process which a terminal performs according to a program.

An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, in the video call system of this embodiment, a terminal 1 distributed in each base is connected to a public network represented by the Internet, a WAN (Wide Area Network), or a LAN (Local Area Network). It is constructed by connecting to each other via a telecommunication line 2 such as the above. At least one of the terminals 1 is the master terminal 11, and the remaining plurality are slave terminals 12.

As shown in FIG. 2, the terminal 1 includes a processor 1a, a main memory 1b, an auxiliary storage device 1c, an operation input device 1d, a microphone 1e, a speaker 1f, an audio codec 1g, a camera 1h, a display 1i, a video codec 1j, and a communication interface. Hardware resources such as 1k are provided, and these are controlled by a controller (system controller, I / O controller, etc.) 11 to perform a cooperative operation.

The auxiliary storage device 1c is a hard disk drive, a flash memory, an optical disk drive, or the like.

The operation input device 1d is a push button that can be operated with a finger, a pointing device such as a touch panel, a track pad, or the like. In the present embodiment, a remote controller capable of wireless communication with the terminal 1 is assumed.

The audio codec 1g encodes the sound collected through the microphone 1e (which means collecting on-site sound, including recording), or decodes the encoded audio information and outputs the audio from the speaker 1f. Or The video codec 1j encodes video captured through the camera 1h, decodes encoded video information, and displays and outputs it on the screen of the display 1i. Each of the audio codec 1g and the video codec 1j can be implemented as software instead of hardware.

The camera 1 h may be built in the terminal 1 or may be externally attached to the terminal 1. In the case of external attachment, it may be internal or external to a general-purpose terminal distributed in the market. In the case of external attachment, a general-purpose camera distributed in the market can be used. The camera 1h receives a control signal from a terminal 1 that is mounted or directly connected to the camera 1h, thereby panning (changing the angle of the optical axis along the horizontal direction) and tilting (angle of the optical axis along the vertical direction). (Change) and / or zoom (change of focal length) is preferable.

The communication interface 1g is a device for performing information communication via the telecommunication line 2 and is typified by NIC (Network Interface Card) or wireless LAN transceiver, but besides these, USB (Universal Serial Bus), IEEE 1394, etc. The interface can also be adopted.

The terminal 1 is basically a dedicated device manufactured for the purpose of constructing this system. However, it does not prevent the terminal 1 according to the present invention from being configured by installing a program necessary for a general-purpose personal computer, workstation, video game machine or the like.

The program to be executed by the processor 1a is stored in the auxiliary storage device 1c. When the program is executed, the program is read from the auxiliary storage device 1c into the main memory 1b and decoded by the processor 1a. The terminal 1 operates the hardware resource according to the program, and exhibits the function of the master terminal 11 shown in FIG. 3 and the function of the slave terminal 12 shown in FIG.

The function units of the main terminal 11 include a setting information storage unit 111, a call request transmission unit 112, a maximum rate calculation unit 116, a maximum rate designation information transmission unit 117, a call reception unit 113, a call output control unit 114, and a call transmission unit. 115, an operation input reception unit 118, and a command transmission unit 119.

The functional units of the slave terminal 12 include a setting information storage unit 124, a call request receiving unit 121, a maximum rate designation information receiving unit 125, a call receiving unit 122, a call output control unit 123, a call transmitting unit 127, and command reception. Part 126 is provided.

Prior to the description of each functional unit, a video call mode realized by the video call system of this embodiment will be described. In this embodiment, “Group View Mode” in which all bases can see the images of all other bases at the same time, and only one selected base can watch the pictures of all other bases at the same time. Other sites can appropriately switch to “single view mode” in which only the video of the one site is viewed.

Regardless of the group view mode or the single view mode, each terminal 1 installed at each site participating in the video call has a session connection individually. In the case where five bases participate, the terminal 1 at one base is the master terminal 11 and each terminal 1 at the remaining four bases is the slave terminal 12, each of the

terminals

11 and 12 is the other four. A session connection with the

terminals

11 and 12 is made individually.

As shown in FIG. 5, in the group view mode, the

terminals

11 and 12 installed at each site participating in the video call capture images shot at their own sites by all other users. It transmits toward the terminals 11 and 12 (indicated by broken lines in the figure). In the case where five bases are participating, each terminal 11, 12 sends video to each of the other four

terminals

11, 12 and receives video from each of the other four

terminals

11, 12. . These videos are arranged and displayed on the screen of the display 1i. In the group view mode, since the bandwidth of the communication line 2 to which the

terminals

11 and 12 are connected is inevitably squeezed, the transfer rate of the video transmitted from the

terminals

11 and 12 is set to the maximum transfer rate described later. The following are to be suppressed. Incidentally, the group view mode is immediately after the start of the video call.

As shown in FIG. 6, in the single view mode, one terminal 11 out of the

terminals

11 and 12 installed at each site participating in the video call captures a video image taken at its own site. Transmission is performed toward all other terminals 12 (indicated by a solid line in the figure). On the other hand, the other terminal 12 transmits the video imaged at its installation site to the one terminal 11 (indicated by a broken line in the figure). However, the other terminals 12 do not transmit / receive video to / from each other. As a result, at least the bandwidth of the communication line 2 to which the other terminal 12 is connected is afforded. Accordingly, the transfer rate of the video transmitted from one terminal 11 to each of the other terminals 12 is allowed to be larger than that of the video transmitted in the group view mode. It is not always necessary to suppress the video transfer rate below the maximum transfer rate. In this embodiment, the video has a relatively small frame size (definition) (for example, 960 × 540 pixels or 720 × 480 pixels), and the video has a relatively large frame size (for example, 1920 × 1080). Pixel). Each of the other terminals 12 receives a high-definition video from one terminal 11 and displays it on substantially the entire screen of the display 1i. In turn, the other terminals 12 in the single view mode each send a low-quality video to one terminal 11. As in the group view mode, it is preferable to suppress the transfer rate of the video transmitted from the other terminal 12 in the single view mode to the maximum transfer rate or less. The one terminal 11 that has received the video from each of the other terminals 12 arranges and displays the video on the screen of the display 1 i as in the group view mode.

In the example shown in FIG. 6, the main terminal 11 is a subject that attracts the attention of others in the single view mode. However, as shown in FIG. 7, any one of the slave terminals 12 is in the single view mode. Is selected as a subject that attracts the attention of others, and a high-definition video is transmitted from the terminal 12 to each of the other terminals 11 and 12 (shown by a solid line in the figure). A mode in which a low-quality video is transmitted from each to the terminal 12 (shown by a broken line in the figure) can be taken. Under this situation, the user of the main terminal 11 can remotely operate pan, tilt or zoom of the camera 1h of the slave terminal 12.

As for audio, regardless of the group view mode or the single view mode, the

terminals

11 and 12 always transmit the audio collected at their installation bases to all

other terminals

11 and 12. The bit rate of audio data is an order of magnitude smaller than that of video data, and transmission from all

terminals

11 and 12 participating in a lecture or a meeting to all

other terminals

11 and 12 This is probably because it will not cause a shortage of communication bandwidth.

Each functional unit of the main terminal 11 will be described. The setting information storage unit 111 stores various setting information using the storage area of the main memory 1b or the auxiliary storage device 1c. As the setting information, first, there is telephone book (or address book) information. The phone book information is obtained by associating identification information of other terminals 1 (for example, a maximum of 100 cases) that can be candidates for a video call partner and attribute information related to the terminal 1. FIG. 8 illustrates phone book information. The setting information storage unit 111 stores identification information and attribute information in association with an ID number or the like for each terminal 1 for other terminals 1. The identification information is information for identifying a communication destination represented by, for example, an IP address, a SIP (Session Initiation Protocol) address, or another URI. The attribute information is information related to the other party's name or name, affiliation, location, and other destinations, and is character string information in this embodiment.

Other setting information includes allowable bandwidth information related to the main terminal 11. The permissible bandwidth information indicates the permissible transfer rate of data that can be transmitted via the communication line 2 connected to each terminal 1 and / or the permissible transfer rate of receivable data. Information. The allowable transfer rate is the communication speed quality of how much bit rate data can be transmitted / received by the communication line 2 to which the terminal 1 is connected during the video call, or the video call In order to clarify the communication speed limit taking into account the balance with other services (or others sharing the same line 2), such as to what extent it is allowed to occupy the communication bandwidth I can say that. The size of the allowable transfer rate varies depending on the type of the communication line 2 to which the terminal 1 is connected, the number of sharers of the line 2, the location of the terminal 1, the date or time zone, and various other circumstances.

The allowable bandwidth information may be set and input in advance by the terminal 1 or the user or administrator of the system. In this case, the allowable bandwidth information related to the terminal 1 is set as part of the setting information. Store in the storage unit 111. Further, when the allowable bandwidth information for the other terminal 1 has already been acquired, this allowable bandwidth information is also associated with the ID number or the like for identifying the other terminal 1 in the setting information storage unit 111. Remember. However, the allowable bandwidth information is not necessarily set and input in advance and stored in the setting information storage unit 111.

The above setting information may be manually input directly or may be transmitted from another terminal 1 or a computer connected via the telecommunication line 2. The terminal 1 accepts manual input of setting information via the operation input device 1 d or receives it using the function of the communication interface 1 k and stores it in the setting information storage unit 111.

Although not shown in FIG. 8, it is also possible to accumulate identification information and attribute information relating to other terminals 1 that have made a video call in the past as a past call history in the telephone directory. . Specifically, information indicating whether the call was made (transmitted) from us or received (received) from the other party, a time stamp indicating the date and time when the video call was made with the terminal 1, etc. Also stored in the setting information storage unit 111. In particular, for a plurality of terminals 1 that have participated in video lectures or video conferences held in the past, it is conceivable to store information to that effect and time stamps indicating the dates and times of lectures or conferences.

When holding a video call, that is, a video lecture or a video conference, the call request transmitting unit 112 sends a call request for performing a video call to the terminal 1 participating in the lecture or the conference. Send using the function of. In principle, the call request is transmitted from the master terminal 11 to the slave terminal 12. Of course, this does not hinder the mode of transmitting a call request from the slave terminal 12 to the master terminal 11.

The main terminal 11 displays on the screen of the display 1i a list of other terminals 1 that can be candidates for video call destinations, that is, candidates for participation in lectures or meetings. FIG. 9 shows a candidate list display example. The terminal 1 that is first displayed as a candidate is the terminal 1 that has participated in a lecture or a meeting in the past (the history information is left in the setting information storage unit 111). The main terminal 11 reads the identification information from the setting information storage unit 111 for each of the plurality of candidate terminals 1. Then, based on the identification information, a live icon request that is information for requesting the terminal 1 to transmit a live icon (symbol B in the figure) is transmitted. The live icon is a real-time video or still image taken at the place where the terminal 1 is installed. The size of the live icon (for example, 192 × 108 pixels) is smaller than the size of the video exchanged during the video call. The live icon frame rate is about 5 fps or more.

In the system of this embodiment, as a rule, the terminals 1 are interconnected in a peer-to-peer manner via the telecommunication line 2. In other words, it is not necessary to use another relay server or a relay device such as an MCU when conducting a video lecture or a video conference. When the identification information does not require address resolution such as an IP address, a live icon request can be immediately transmitted to the terminal 1 using the identification information. When the identification information requires address resolution, such as a SIP address, the invitee terminal 12 and the callee terminal 12 can be contacted by transmitting an invitation message to another computer (for example, a SIP proxy server) using the identification information. Establish a session between them and then send a live icon request. Alternatively, the identification information is transmitted to another computer having an address resolution capability (for example, a DNS (Domain Name System) server), and an IP address corresponding to the identification information is received from the computer. A live icon request is transmitted to the terminal 1 using.

The terminal 1 that has received the live icon request normally transmits the live icon captured by the camera 1h to the terminal 1 that has caused the live icon request. The main terminal 11 receives the live icon returned from each terminal 1, and displays it on the screen of the display 1i together with the attribute information (reference symbol A in the figure) of the terminal. Since the live icon cannot be displayed for the terminal 1 that has not received the live icon, an image or a character string indicating that fact is displayed. In the example shown in FIG. 9, the display of “Connecting ...” (reference symbol C) indicates that a live icon request is transmitted to the terminal 1 and a response is awaited. The display of “communication impossible” (symbol D in the figure) indicates that a response has not been returned until a certain time has elapsed after transmitting a live icon request to the terminal 1, that is, for some reason (the power supply of the terminal 1 is The communication line to which the terminal 1 is connected is interrupted, etc., indicating that it is impossible to establish a session with the terminal 1. A display of “not displayable” (symbol E in the figure) indicates that a live icon request is transmitted to the terminal 1, but the live icon request is rejected, in other words, a response that the live icon is not transmitted is live. Indicates that it was sent instead of an icon. In the display of “busy” (symbol F in the figure), a live icon request is transmitted to the terminal 1, but a response indicating that a video call is already being made with another terminal 1 is sent instead of the live icon. It shows that it has come.

Thus, the master terminal 11 sends operation inputs for designating a plurality of slave terminals 12 to be participants in a video lecture or video conference from the candidates displayed on the screen via the operation input device 1d. And accept. The user of the master terminal 11 operates the operation input device 1d to move the cursor (symbol G in the figure), and clicks the information display column (symbols A and B in the figure) of the desired slave terminal 12. The main terminal 11 that has received this operation knows the terminal 12 corresponding to the clicked display field as a participant, and starts the video call to the terminal 12 based on the identification information related to the terminal 12. Send the requested call request. This call request includes the identification information and ID number of each of the plurality of slave terminals 12 and the master terminal 11 that are participants in a video lecture or video conference. Even if the identification information related to the slave terminal 12 requires address resolution, if the session has already been established or address resolution has already been completed at the live icon request transmission stage, a call request is made directly to the slave terminal 12. Can be sent. Otherwise, session establishment or address resolution is performed in the same manner as when the live icon request is transmitted, and a call request is transmitted to the slave terminal 12. Incidentally, the terminal 1 that displays “communication impossible” or “busy” instead of the live icon cannot be designated as a participant (the cursor cannot be moved to the information display field related to the terminal 1). It is like that.

The maximum rate calculation unit 116 calculates the maximum value of the transfer rate of the video data that each of the

terminals

11 and 12 should transmit during the video call prior to the start of the video lecture or video conference. At this time, the allowable transfer rate for each of the plurality of slave terminals 12 as participants and the allowable transfer rate for the master terminal 11 itself are referred to.

Describes how to calculate the maximum transfer rate. First, the master side terminal 11 transmits / receives data packets to / from each of the slave side terminals 12 that have sent a call request by a known method (counting delay time of data packet transmission / reception, error packet rate, etc.). Alternatively, each of the slave terminals 12 receives a communication line from the slave terminals 12 that have transmitted the transmission request, by receiving the allowable bandwidth information that the slave terminals 12 store and hold in advance as setting information. 2 to obtain and aggregate the allowable transfer rate of data that can be transmitted / received via the network. However, when the allowable bandwidth information for the slave terminal 12 is already stored in the setting information storage unit 111 as a part of the setting information, the stored information in the setting information storage unit 111 may be read. .

Not only that, the main terminal 11 uses a known method for transmitting and receiving data packets to and from the slave terminal 12 on a trial basis, or the allowable bandwidth that the main terminal 11 itself stores and holds as setting information in advance. By reading the width information, the main terminal 11 knows the allowable transfer rate of data that can be transmitted / received via the communication line 2.

Then, for each terminal 11, 12 that is a participant in a video lecture or video conference, the maximum value of the transfer rate of the video image to be transmitted from the terminal 11, 12 to the

other terminal

11, 12 is calculated. . Basically, the allowable transmission rate via the communication line 2 to which the

terminals

11 and 12 are connected is determined by the number of slave terminals 12 participating in a video lecture or video conference, in other words, the number of participating bases other than itself. Divide by to get the maximum rate of data sent during a video call.

However, in practice, the entire bandwidth of the communication line 2 cannot always be used only for sending video data. Data to be transmitted from the

terminals

11 and 12 during a video call includes not only video but also audio, a header defined by a protocol, an error correction (particularly, forward error correction) code, and the like. Because. Therefore, it can be said that it is more desirable to determine the maximum rate of video to be transmitted by subtracting the corresponding band. That is,
(Maximum rate of video to be transmitted during video call) = (Allowable transmission rate of communication line 2) ÷ (Number of participating slave terminals 12) − (Band for transmission of protocol header, error correction code, etc.)
As described above, the maximum value of the transfer rate of the video to be transmitted from the

terminals

11 and 12 to the

other terminals

11 and 12 is calculated.

However, the allowable transmission rate is not divided by the number of slave terminals 12, but is multiplied by a ratio corresponding to the number of slave terminals 12 according to the allowable transmission rate, or the allowable transmission rate is discounted. It is also conceivable that the maximum transfer rate of the video transmitted from each terminal 11, 12 is determined by discounting the allowable transmission rate by multiplying a predetermined ratio that does not depend on the number of the following terminals 12 according to the rate.

The maximum rate designation information transmission unit 117 transmits the maximum rate designation information describing the value of the maximum transfer rate calculated by the maximum rate calculation unit 116 to each of the slave terminals 12 designated as participants in a video lecture or a video conference. On the other hand, it transmits using the function of the communication interface 1k. In the present embodiment, the maximum transfer rate of video transmitted to the

other terminals

11 and 12 is individually calculated for each of the main terminal 11 and the slave terminal 12. Therefore, the maximum rate designation information transmitting unit transmits the maximum rate designation information describing the maximum transfer rate corresponding to each slave terminal 12 to each slave terminal 12. The value of the maximum transfer rate for the main terminal 11 itself is temporarily stored in the main memory 1b or the auxiliary storage device 1c of the main terminal 11.

The call receiving unit 113 receives the video and audio transmitted from the slave terminal 12 after the video call is started, using the function of the communication interface 1k. In the group view mode, video data is received from all the slave terminals 12 participating in a video conference or a video lecture.

In the single view mode, the processing differs depending on which terminal 11 or 12 is the subject that attracts the attention of others. While the main terminal 11 itself is a subject that attracts the attention of others, low-definition video data is received from all participating slave terminals 12. While any slave terminal 12 is a subject that attracts the attention of others, high-quality video data is received only from the slave terminal 12.

The call output control unit 114 displays the video during a call received from any one or all of the slave terminals 12 on the screen of the display 1i, and the voice during a call received from all the slave terminals 12 to the speaker 1f. To output sound. FIG. 10 shows a display example of the image of the other party during the video call. However, what is shown in FIG. 10 is a call screen in the group view mode, and the call screen in the single view mode is different from this. On the call screen in the group view mode, the video (symbol H in the figure) taken at all participating slave terminals 12 is displayed in parallel with the same dimensions. In addition, although not shown, the call output control unit 114 can also display a video image captured by the camera 1h at its installation location in a small size within the call screen. Further, the call output control unit 114 superimposes the voice received from each slave terminal 12 and outputs the voice from the speaker 1f.

The call transmission unit 115 sends the video captured by the camera 1h and the sound collected by the microphone 1e at the installation location of the main terminal 11 to the slave terminal 12 participating in a video lecture or a video conference. Transmission is performed using the function of the communication interface 1k. In the group view mode, the same video data is transmitted to all participating slave terminals 12. For this purpose, the video captured by the camera 1h is encoded into video data having a rate equal to or lower than the maximum transfer rate calculated by the maximum rate calculation unit 116, and then transmitted to each of the slave terminals 12. Methods for increasing or decreasing the bit rate of video data include adjusting the quality after encoding (in other words, the degree of compression), changing the compression algorithm, changing the frame rate, or the size (number of pixels) of the video frame. There are known methods for scaling. In the present embodiment, since the video size is fixed in the group view mode and the single view mode, the bit rate of the video data is suppressed to the maximum transfer rate or less by a method other than enlarging or reducing the size of the video frame.

In the single view mode, the processing differs depending on which terminal 11 or 12 is the subject that attracts the attention of others. While the main terminal 11 itself is a subject that attracts the attention of others, the same high-definition video data is transmitted to all participating slave terminals 12. The transfer rate of the high-quality video data is not necessarily restricted by the maximum transfer rate calculated by the maximum rate calculation unit 116. This is because each slave terminal 12 receives video only from the master terminal 11.

On the other hand, in the single view mode, while any slave terminal 12 is a subject that attracts the attention of others, low-quality video data is transmitted only to the slave terminal 12. At this time, the low-quality video data is preferably encoded into data having a rate equal to or lower than the maximum transfer rate calculated by the maximum rate calculation unit 116. However, it is not necessarily bound by the maximum transfer rate. This is because video exchange does not occur between the

terminals

11 and 12 other than the slave terminal 12 that is the subject that attracts the attention of others.

The operation input reception unit 118 is an operation input for switching between the group view mode and the single view mode, and an operation input for selecting any one of the

terminals

11 and 12 in the single view mode as a subject to attract the attention of others. Is received via the operation input device 1d. For example, the user of the master side terminal 1 operates the operation input device 1d on the screen of the group view mode shown in FIG. Click the “1 site” button (symbol P in the figure) after matching the display field. The master side terminal 11 that has received this operation knows that it should be switched from the group view mode to the single view mode, and further, the slave side terminal 12 corresponding to the position of the cursor receives the attention of others in the single view mode. Know as the terminal 12 that should be the subject of the collection. When the user simply wants to switch between the group view mode and the single view mode (a state in which the main terminal 11 is the subject that attracts the attention of others), the user presses a specific key of the operation input device 1d, etc. do it. The main terminal 11 that has received this operation knows that switching from the group view mode to the single view mode or from the single view mode to the group view mode is required.

In response to the operation input received by the operation input reception unit 118, the command transmission unit 119 is instructed to switch between the group view mode and the single view mode, and / or any of the

terminals

11 and 12 in the single view mode. A switching command, which is a command for instructing whether or not it has been selected, is transmitted to each slave terminal 12 using the function of the communication interface 1k.

Further, under the situation of the single view mode in which the slave terminal 12 is selected as a subject that attracts the attention of others, the operation input reception unit 118 is performed by the user of the master terminal 11. The operation input indicating that the pan, tilt or zoom of the camera 1h associated with the camera 1h should be operated can be received via the operation input device 1d. When the command operation unit 119 receives the operation input, the command operation unit 119 sends a camera operation command corresponding to the operation input to operate the pan, tilt, or zoom of the camera 1 h to the slave terminal 12. And using the function of the communication interface 1k.

Next, each functional unit of the slave terminal 12 will be described. The setting information storage unit 124 stores setting information, in particular, allowable bandwidth information regarding the slave terminal 12 using the storage area of the main memory 1b or the auxiliary storage device 1c. The setting information may be manually input directly or may be transmitted from another terminal 1 or a computer connected via the telecommunication line 2. The terminal 1 accepts input of setting information via the operation input device 1 d or receives it using the function of the communication interface 1 k and stores it in the setting information storage unit 124. However, the allowable bandwidth information is not necessarily set and input in advance and stored in the setting information storage unit 121.

The call request receiving unit 121 receives a call request transmitted from the main terminal 11 by using the function of the communication interface 1k. The call request includes identification information and an ID number of each of the plurality of slave terminals 12 and the master terminal 1 that are participants in a video lecture or a video conference. Therefore, by referring to the call request, the slave terminal 12 can know the identification information of the other participating

terminals

11 and 12 and can establish a session connection with the

terminals

11 and 12. It becomes. The slave terminal 12 that has received the call request from the master terminal 11 is directed toward the other slave terminal 12 described in the call request just as the master terminal 11 has executed for the slave terminal 12. Send further call requests. That is, triggered by the reception of the call request, mutual communication between the slave terminal 12 and the master terminal 11 and mutual communication between the slave terminals 12 are established, and the video lecture hosted by the slave terminal 11 by the slave terminal 12 is established. Or it is decided to participate in a video conference or the like. The slave terminal 12 may return the allowable bandwidth information stored and held in its own setting information storage unit 124 to the master terminal 1 in response to the call request.

The maximum rate designation information receiving unit 125 receives the maximum rate designation information transmitted from the main terminal 11 by using the function of the communication interface 1k. By referring to this maximum rate designation information, the maximum transfer rate of video data to be transmitted, particularly in the group view mode, is obtained. The value of the maximum transfer rate is temporarily stored in the main memory 1b or the auxiliary storage device 1c of the slave terminal 12.

The call receiving unit 122 receives the video and audio transmitted from the main terminal 11 and / or the slave terminal 12 after the start of the video call using the function of the communication interface 1k. In the group view mode, video data is received from the master terminal 11 and all other slave terminals 12 participating in a video conference or a video lecture.

In the single view mode, the processing differs depending on which terminal 11 or 12 is the subject that attracts the attention of others. While the slave terminal 11 itself is a subject that attracts the attention of others, it receives low-quality video data from the participating master terminal 11 and all other slave terminals 12. While either the master terminal 11 or the slave terminal 12 other than itself is the subject that attracts the attention of others, high-quality video data is received only from the master terminal 11 or the slave terminal 12 To do.

The call output control unit 123 displays a video during a call received from any one or all of the main side terminal 11 and the subordinate terminal 12 on the screen of the display 1i and all of the main side terminal 11 and the subordinate side terminal 12. The voice during a call received from the voice is output from the speaker 1f. As for the sound, the sound received from the

terminals

11 and 12 is superimposed and output from the speaker 1f.

The call transmission unit 127 receives the video captured by the camera 1h at the installation location of the slave terminal 12 and the sound collected by the microphone 1e and / or the master terminal 11 participating in the video lecture or video conference. It transmits to the side terminal 12 using the function of the communication interface 1k. In the group view mode, the same video data is transmitted to the participating master terminal 11 and all other slave terminals 12. For this purpose, the video captured by the camera 1h is calculated by the maximum rate calculation unit 116 of the main terminal 11 and encoded into video data having a rate equal to or less than the maximum transfer rate described in the maximum rate designation information. The data is transmitted to each of the terminal 11 and the slave terminal 12.

In the single view mode, the processing differs depending on which terminal 11 or 12 is the subject that attracts the attention of others. While the slave terminal 12 itself is a subject that attracts the attention of others, the same high-definition video data is transmitted to the participating master terminal 11 and all other slave terminals 12. . The transfer rate of the high-quality video data is not necessarily restricted by the maximum transfer rate described in the maximum rate designation information. This is because the master terminal 11 and the other slave terminals 12 receive video only from this side.

While either the master terminal 11 or the slave terminal 12 other than itself is the subject that attracts the attention of others, the low-definition video data only for the master terminal 11 or the slave terminal 12 Send. The low-quality video data at this time is preferably encoded into data having a rate equal to or less than the maximum transfer rate described in the maximum rate designation information. However, it is not necessarily bound by the maximum transfer rate. This is because video exchange does not occur between the

terminals

11 and 12 other than the

terminals

11 and 12 that are the subject that attracts the attention of others.

The command receiving unit 126 receives the switching command transmitted from the main terminal 11 using the function of the communication interface 1k. By referring to the switching command, it is known whether the terminal is currently in the group view mode or the single view mode, and which of the

terminals

11 and 12 is the subject that attracts the attention of others in the single view mode. To get.

In addition, under the situation of the single view mode in which the slave terminal 12 is selected as a subject that attracts the attention of others, the command receiving unit 126 receives a camera operation command provided from the master terminal 11 There is. When a camera operation command is received, a control signal is input to the camera 1h based on the camera operation command to operate pan, tilt, or zoom.

The outline of the procedure of processing executed by the terminal 1 constituting the video call system of the present embodiment during the video call will be outlined. As shown in FIG. 11, when the main terminal 11 is currently in the group view mode (step S1), the low-definition video transmitted from all the slave terminals 12 participating in the video lecture or video conference or the like. And the audio are received (step S2), and the received video and audio are output via the display 1i and the speaker 1f (step S3). At the same time, the user's own video captured by the camera 1h and the user's own voice picked up by the microphone 1e are transmitted to all participating slave terminals 12 (step S4). In step S4, the video data is encoded into a low-quality video, and the transfer rate is suppressed below the maximum transfer rate.

If the current mode is the single view mode and the main terminal 11 itself is selected as a subject that attracts the attention of others (step S5), the low-level transmitted from all of the participating slave terminals 12 that are also participating. The quality video and audio are received (step S6), and the received video and audio are output via the display 1i and the speaker 1f (step S7). At the same time, the user's own video captured by the camera 1h and the user's own voice collected by the microphone 1e are transmitted to all participating slave terminals 12 (step S8). In step S8, the video data is encoded into a high quality video. The transfer rate is not necessarily suppressed below the maximum transfer rate.

When currently in the single view mode and any of the slave terminals 12 is selected as a subject that attracts the attention of others, while receiving a high-definition video transmitted from only the slave terminal 12, Audio transmitted from all the slave terminals 12 is received (step S9), and the received video and audio are output via the display 1i and the speaker 1f (step S10). At the same time, the user's own video captured by the camera 1h and the user's own voice picked up by the microphone 1e are transmitted only to the slave terminal 12 that is the subject that attracts the attention of others (step S11). In step S11, the video data is encoded into a low-quality video, and the transfer rate is suppressed below the maximum transfer rate.

Also, an operation input indicating that the user of the main terminal 11 should switch between the group view mode and the single view mode, or a subject that attracts the attention of others in the single view mode for any one of the

terminals

11 and 12 Is received (step 12), a switching command corresponding to the operation input is transmitted to all participating slave terminals 12 (step S13).

The main terminal 11 repeats the above steps S1 to S13 until the end of the video lecture or video conference.

As shown in FIG. 12, when the slave terminal 12 is currently in the group view mode (step S14), from the master terminal 11 participating in the video lecture or video conference and all other slave terminals 12 The low-definition video and audio transmitted from is received (step S15), and the received video and audio are output via the display 1i and the speaker 1f (step S16). At the same time, the self-image captured by the camera 1h and the own sound collected by the microphone 1e are transmitted to the main terminal 11 and all other subordinate terminals 12 (step S17). In step S17, the video data is encoded into a low-quality video, and the transfer rate is suppressed below the maximum transfer rate.

When the current mode is the single view mode and the slave terminal 12 itself has been selected as a subject that attracts the attention of others (step S18), it is also transmitted from the master terminal 11 and all the slave terminals 12. The low-quality video and audio are received (step S19), and the received video and audio are output via the display 1i and the speaker 1f (step S20). At the same time, the self-image captured by the camera 1h and the own sound collected by the microphone 1e are transmitted to the main terminal 11 and all other subordinate terminals 12 (step S21). In step S21, the video data is encoded into a high quality video. The transfer rate is not necessarily suppressed below the maximum transfer rate.

If the current mode is the single view mode and the slave terminal 12 other than the master terminal 11 or the slave terminal 12 other than itself is selected as a subject that attracts the attention of others, transmission is performed only from the master terminal 11 or the slave terminal 12 While receiving the high-definition video, the audio transmitted from all the slave terminals 12 is received (step S22), and the received video and audio are output via the display 1i and the speaker 1f (step S23). At the same time, the user's own video captured by the camera 1h and the user's own voice collected by the microphone 1e are transmitted only to the main terminal 11 or the slave terminal 12 that is the subject that attracts the attention of others. (Step S24). In step S24, the video data is encoded into a low-quality video, and the transfer rate is suppressed below the maximum transfer rate.

Further, when a switching command is provided from the main terminal 11, it is received (step S25).

The slave terminal 12 repeats the above steps S14 to S25 until the end of the video lecture or video conference.

The functions of the master terminal 11 and slave terminal 12 will be supplemented. When the communication connection with any of the

other terminals

11 and 12 is interrupted during the video call (regardless of the group view mode or the single view mode), each of the

terminals

11 and 12 has lost the communication connection. , 12 and automatically re-send the call request to attempt reconnection.

After the start of the video call, the slave terminal 12 can leave the currently participating video call according to the convenience of the user of the slave terminal 12. When the slave terminal 12 receives, via the operation input device 1d, an operation input that instructs the user to leave the video call, information indicating that the slave terminal 12 is to leave the video call is displayed. And to the other slave terminal 12. The master terminal 11 and the slave terminal 12 that have received the above information disconnect the communication connection with the slave terminal 12 that is about to leave the video call.

In addition, since the number of sites participating in the video call decreases, the main terminal 11 calculates the maximum transfer rate again in the same manner as when the video call starts, and describes the calculated maximum transfer rate. The rate designation information is transmitted to each of the slave terminals 12 other than the slave terminal 12 that leaves the video call. The slave side terminal 12 receives the maximum rate designation information brought again from the master side terminal 11. Thereafter, the master terminal 11 and the slave terminal 12 that make a video call each generate and transmit a video that is less than or equal to the recalculated maximum transfer rate at least in the group view mode.

The main terminal 11 can newly add a participating base to a video call that has already been started. The master side terminal 11 receives an operation input including designation of the slave side terminal 12 to newly participate in the already started video call by the user's hand via the operation input device 1d. For example, as shown in FIG. 9, a candidate for a slave terminal 12 to be newly joined is displayed on the screen of the display 1i, and the slave terminal 12 to be a new participant is designated as a user among the candidates. Let The master terminal 11 that has received the operation input transmits a call request for requesting the slave terminal 12 to start a video call based on the identification information related to the slave terminal 12 designated as a new participant. . This call request includes identification information and ID numbers of each of the plurality of slave terminals 12 and the master terminal 11 already participating in the video call. The slave terminal 12 designated as the new participant receives the call request from the master terminal 11, and already participates in the video call by referring to the identification information and ID number included in the call request. A call request is transmitted to each slave terminal 12 that is in charge. Through these processes, communication is established between the slave terminal 12 newly participating in the video call and the slave terminal 12 and the master terminal already participating in the video call. The master terminal 11 also transmits information including identification information and ID number of the slave terminal 12 designated as a new participant to the slave terminal 12 already participating in the video call. The slave terminal 12 having received this information may transmit a call request to the slave terminal 12 newly participating in the video call.

Furthermore, since the number of sites participating in the video call increases, the main terminal 11 calculates the maximum transfer rate again in the same manner as when starting the video call, and describes the calculated maximum transfer rate. The rate designation information is transmitted to each of the slave terminals 12 (including bases newly participating in video calls). The slave side terminal 12 receives the maximum rate designation information brought again from the master side terminal 11. Thereafter, the master terminal 11 and the slave terminal 12 that make a video call each generate and transmit a video that is less than or equal to the recalculated maximum transfer rate at least in the group view mode.

In addition, the main terminal 11 can selectively exclude any of the bases participating in the video call from the video call. The master side terminal 11 receives an operation input including designation of the slave side terminal 12 to be excluded from the already started video call by the user's hand via the operation input device 1d. The master terminal 11 that has received the operation input transmits information including the identification information and ID number related to the slave terminal 12 to be excluded to the slave terminals 12 other than the slave terminal 12. The slave terminal 12 that has received the information disconnects the communication connection with the slave terminal 12 that should be excluded. In addition, the master terminal 11 transmits information indicating that to the slave terminal 12 to be excluded. The slave terminal 12 that has received this information may disconnect the communication connection with the other slave terminals 12 and the master terminal 11.

In addition, since the number of sites participating in the video call decreases, the main terminal 11 calculates the maximum transfer rate again in the same manner as when the video call starts, and describes the calculated maximum transfer rate. The rate designation information is transmitted to each of the slave terminals 12 other than the slave terminal 12 excluded from the video call. The slave side terminal 12 receives the maximum rate designation information brought again from the master side terminal 11. Thereafter, the master terminal 11 and the slave terminal 12 that make a video call each generate and transmit a video that is less than or equal to the recalculated maximum transfer rate at least in the group view mode.

According to the video call system of the present embodiment, transmission rate optimization processing is not required at the start of a video call, and video transmission / reception and screen display can be started quickly in the group view mode. Immediately after the image stabilizes.

Furthermore, although it is a system in which three or more parties can participate at the same time, it is possible to send high-definition video to a limited number of people in the single view mode. The problem can be solved effectively, and it can be put to practical use at a relatively low cost without using a dedicated line, MCU, or IP multicast.

Note that the present invention is not limited to the embodiment described in detail above. The method for calculating the maximum transfer rate of video by the maximum rate calculation unit 116 of the main terminal 11 is not limited to that in the above embodiment.

If the communication line 2 to which the

terminals

11 and 12 are connected is an xDSL line, the transfer rate of data that can be transmitted via the line 2 to which the

terminals

11 and 12 are connected, that is, the uplink transfer rate is the bottle. It becomes a neck. This is because the xDSL line has an uplink communication speed that is significantly slower than the downlink communication speed. In such a case, it is reasonable to calculate the maximum video transfer rate by referring only to the uplink transfer rate of the line 2 to which the

terminals

11 and 12 are connected. The transfer rate of data that can be received through the network, that is, the downlink transfer rate may be ignored.

Conversely, if the uplink and downlink are symmetric lines with the same communication speed, the maximum transfer rate may be calculated by referring only to the uplink transfer rate, and the maximum transfer rate may be calculated by referring only to the downlink transfer rate. It may be calculated. In the latter case, for example, the maximum transfer rate of video is calculated by dividing or discounting the minimum value that is a bottleneck among the downlink transfer rates for each terminal 11 and 12 by the number of slave terminals 12. It is possible to do.

Of course, the maximum video transmission rate may be calculated by referring to both the upstream transfer rate and the downstream transfer rate. After all, in the group view mode, when each terminal 11, 12 receives video from all the

other terminals

11, 12 simultaneously, the downlink transfer rate of the communication line 2 to which the terminal 11, 12 is connected is Do not puncture, and when each terminal 11, 12 transmits video to all

other terminals

11, 12 simultaneously, the uplink transfer rate of the communication line 2 to which the terminal 11, 12 is connected is punctured No, it is required to calculate the maximum transfer rate so as to satisfy the above two points.

In addition, the specific configuration of each part, processing procedure, and the like can be variously modified without departing from the spirit of the present invention.

The present invention can be used, for example, as a system for realizing video lectures or video conferences between multiple points.

DESCRIPTION OF SYMBOLS 1 ... Terminal 11 ... Master side terminal 12 ... Slave side terminal

Claims

It is a system that realizes a video call function for transmitting and receiving video between terminals installed at each of three or more bases, and any one terminal is a master terminal and the remaining terminals are slave terminals. ,
The main terminal is
At the start of a video call, refer to the transfer rate of data that can be transmitted for each terminal via the communication line connected to the terminal, and discount the transfer rate according to the number of slave terminals A maximum rate calculation unit that calculates the maximum value of the transfer rate that should be transmitted during a video call from each terminal to another terminal,
A maximum rate designation information transmitting unit that transmits maximum rate designation information describing the calculated maximum transfer rate to each of the slave terminals; and
A call transmission unit that generates video data at a rate equal to or less than the calculated maximum transfer rate from video captured by the camera at the installation site of the main terminal, and transmits the video data to each of the slave terminals;
A call receiver for receiving video data transmitted from each of the slave terminals;
A call output control unit for displaying received video data on a display screen;
The slave terminal
A maximum rate designation information receiving unit for receiving maximum rate designation information transmitted from the main terminal at the start of a video call;
Generate video data at a rate equal to or less than the maximum transfer rate described in the maximum rate specification information from the video captured by the camera at the location where the slave terminal is installed for each of the master terminal and other slave terminals. A call transmitter that transmits
A call receiver that receives video data transmitted from each of the master terminal and the other slave terminals;
A video call system comprising: a call output control unit for displaying received video data on a display screen.
It is a system that realizes a video call function for transmitting and receiving video between terminals installed at each of three or more bases, and any one terminal is a master terminal and the remaining terminals are slave terminals. ,
The main terminal is
When starting a video call, refer to the transfer rate of data that can be received via the communication line connected to the terminal for each terminal, and discount the transfer rate according to the number of slave terminals. A maximum rate calculation unit that calculates the maximum value of the transfer rate that should be transmitted during a video call from each terminal to another terminal,
A maximum rate designation information transmitting unit that transmits maximum rate designation information describing the calculated maximum transfer rate to each of the slave terminals; and
A call transmission unit that generates video data at a rate equal to or less than the calculated maximum transfer rate from video captured by the camera at the installation site of the main terminal, and transmits the video data to each of the slave terminals;
A call receiver for receiving video data transmitted from each of the slave terminals;
A call output control unit for displaying received video data on a display screen;
The slave terminal
A maximum rate designation information receiving unit for receiving maximum rate designation information transmitted from the main terminal at the start of a video call;
Generate video data at a rate equal to or less than the maximum transfer rate described in the maximum rate specification information from the video captured by the camera at the location where the slave terminal is installed for each of the master terminal and other slave terminals. A call transmitter that transmits
A call receiver that receives video data transmitted from each of the master terminal and the other slave terminals;
A video call system comprising a call output control unit for displaying received video data on a display screen.
Group view mode in which video data is transmitted from all terminals to each of the other terminals, and all terminals display and output videos from all bases other than their own base, and each of the main side terminals to each of the subordinate terminals The slave terminal can switch between the single view mode in which the slave terminal displays and outputs the video of the installation site of the master terminal,
The main terminal is
An operation input receiving unit that receives an operation input indicating that switching between the group view mode and the single view mode is to be performed;
In addition to further comprising a command transmission unit that transmits to each of the slave terminals a switching command that is a command for switching between the group view mode and the single view mode in response to the received operation input.
The call transmission unit generates video data having a higher transfer rate than the group view mode without being restricted by the maximum transfer rate in the single view mode, and transmits the video data to each of the slave terminals.
The slave terminal is
Further comprising a command receiving unit for receiving a switching command transmitted from the main terminal,
The call transmitter transmits video data only to the main terminal in single view mode,
The video call system according to claim 1 or 2, wherein the call receiving unit receives video data only from the main terminal in the single view mode.
Sends video data from all terminals to each of the other terminals, and all terminals display and output video from all bases other than their own base, and from any one selected terminal to the other It is possible to switch between single view mode that transmits video data to each of the terminals and displays and outputs the video of the installation base of one terminal where the other terminal is selected,
The main terminal is
An operation input accepting unit for accepting an operation input for switching between the group view mode and the single view mode, and an operation input for selecting any one terminal in the single view mode;
Corresponding to the received operation input, the slave terminal receives a switching command that is a command for switching between the group view mode and the single view mode, or a command for instructing which terminal is selected in the single view mode. And a command transmitter for transmitting to each of the above,
When the call transmission unit is in the single view mode and the main terminal itself is selected, the call transmission unit generates video data having a transfer rate higher than that in other cases without being restricted by the maximum transfer rate, and follows it. While transmitting to each of the terminal side, when the single view mode and the slave terminal is selected, the video data is transmitted only to the selected terminal,
When the call receiving unit is in single view mode and the slave terminal is selected, the video data is transmitted only from the selected terminal.
The slave terminal is
Further comprising a command receiving unit for receiving a switching command transmitted from the main terminal,
When the call transmission unit is in the single view mode and the slave terminal itself is selected, the call transmission unit generates video data having a higher transfer rate than the other cases without being restricted by the maximum transfer rate. When transmitting to each of the side terminal and the other slave terminal while the single view mode and the master side terminal or another slave terminal are selected, the video data is transmitted only to the selected terminal. Send
3. The video according to claim 1, wherein the call receiving unit receives video data only from the selected terminal when the single-view mode and the master terminal or another slave terminal are selected. Call system.
Operation input indicating that the operation input reception unit of the master terminal should operate pan, tilt, or zoom of the camera associated with the slave terminal when a single view mode and another slave terminal are selected. Accept
The command transmission unit of the master terminal transmits a camera operation command for operating pan, tilt, or zoom of the camera in response to the received operation input to the selected slave terminal,
The video call system according to claim 4, wherein the command receiving unit of the slave terminal receives a camera operation command transmitted from the master terminal when the slave terminal itself is selected in the single view mode.
The video call system according to claim 1, wherein the video call system is used.
At the start of a video call, refer to the transfer rate of data that can be transmitted for each terminal via the communication line connected to the terminal, and discount the transfer rate according to the number of slave terminals A maximum rate calculation unit that calculates the maximum value of the transfer rate that should be transmitted during a video call from each terminal to another terminal,
A maximum rate designation information transmitting unit that transmits maximum rate designation information describing the calculated maximum transfer rate to each of the slave terminals; and
A call transmission unit that generates video data at a rate equal to or less than the calculated maximum transfer rate from video captured by the camera at the installation site of the main terminal, and transmits the video data to each of the slave terminals;
A call receiver for receiving video data transmitted from each of the slave terminals;
A main terminal including a call output control unit for displaying received video data on a display screen.
The video call system according to claim 2 is used to configure the video call system.
When starting a video call, refer to the transfer rate of data that can be received via the communication line connected to the terminal for each terminal, and discount the transfer rate according to the number of slave terminals. A maximum rate calculation unit that calculates the maximum value of the transfer rate that should be transmitted during a video call from each terminal to another terminal,
A maximum rate designation information transmitting unit that transmits maximum rate designation information describing the calculated maximum transfer rate to each of the slave terminals; and
A call transmission unit that generates video data at a rate equal to or less than the calculated maximum transfer rate from video captured by the camera at the installation site of the main terminal, and transmits the video data to each of the slave terminals;
A call receiver for receiving video data transmitted from each of the slave terminals;
A main terminal including a call output control unit for displaying received video data on a display screen.
The video call system according to claim 3 is used to configure the video call system.
An operation input receiving unit that receives an operation input indicating that switching between the group view mode and the single view mode is to be performed;
A command transmission unit that transmits a switching command that is a command for switching between the group view mode and the single view mode in response to the received operation input, to each of the slave terminals;
A call transmission unit that generates video data from a video captured by a camera at the installation site of the main terminal and transmits the video data to each of the slave terminals;
A call receiver for receiving video data transmitted from each of the slave terminals;
A call output control unit for displaying received video data on a display screen;
The call side transmission unit generates video data having a transfer rate higher than that of the group view mode in the single view mode and transmits the video data to each of the slave side terminals.
The video call system according to claim 4, wherein the video call system is used.
An operation input receiving unit that receives an operation input for switching between the group view mode and the single view mode, and an operation input for selecting any one terminal in the single view mode;
Corresponding to the received operation input, the slave terminal receives a switching command that is a command for switching between the group view mode and the single view mode, or a command for instructing which terminal is selected in the single view mode. A command transmitter for transmitting to each of the
A call transmission unit that generates video data from a video captured by a camera at the installation site of the main terminal and transmits the video data to each of the slave terminals;
A call receiver for receiving video data transmitted from each of the slave terminals;
A call output control unit for displaying received video data on a display screen;
When the call transmission unit is in the single view mode and the main terminal itself is selected, the call transmission unit generates video data having a higher transfer rate than other cases and transmits the video data to each of the slave terminals. On the other hand, when the single view mode and the slave terminal are selected, the video data is transmitted only to the selected terminal,
When the call receiving unit is in a single view mode and a slave terminal is selected, the master terminal receives video data only from the selected terminal.
The video call system according to claim 1, wherein the video call system is used.
A maximum rate designation information receiving unit for receiving maximum rate designation information transmitted from the main terminal at the start of a video call;
Generate video data at a rate equal to or less than the maximum transfer rate described in the maximum rate specification information from the video captured by the camera at the location where the slave terminal is installed for each of the master terminal and other slave terminals. A call transmitter that transmits
A call receiver that receives video data transmitted from each of the master terminal and the other slave terminals;
A slave terminal comprising a call output control unit for displaying received video data on a display screen.
The video call system according to claim 3 is used to configure the video call system.
A command receiving unit that receives a switching command, which is a command for switching between the group view mode and the single view mode, transmitted from the main-side terminal;
A call transmission unit that generates video data from video captured by a camera at the installation site of the slave terminal and transmits the video data to each of the master terminal and the other slave terminals;
A call receiver that receives video data transmitted from each of the master terminal and the other slave terminals;
A call output control unit for displaying received video data on a display screen;
The call transmission unit transmits video data only to the main terminal in the single view mode,
The slave terminal in which the call receiving unit receives video data only from the master terminal in the single view mode.
The video call system according to claim 4, wherein the video call system is used.
Command reception for receiving a switching command, which is a command for switching between the group view mode and the single view mode, or a command for instructing which terminal is selected in the single view mode, transmitted from the main terminal. And
A call transmission unit that generates video data from video captured by a camera at the installation site of the slave terminal and transmits the video data to each of the master terminal and the other slave terminals;
A call receiver that receives video data transmitted from each of the master terminal and the other slave terminals;
A call output control unit for displaying received video data on a display screen;
When the call transmission unit is in the single view mode and the slave terminal itself is selected, each of the master terminal and the other slave terminals generates video data having a higher transfer rate than other cases. On the other hand, when the single-view mode and the master terminal or another slave terminal are selected, the video data is transmitted only to the selected terminal,
A slave terminal that receives video data only from the selected terminal when the call receiving unit is in the single view mode and the master terminal or another slave terminal is selected.