JP6289178B2 - Call conferencing system - Google Patents

Description

  The present invention relates to a telephone conference system that realizes an audio conference on an IP (Internet Protocol) network.

In many cases, the call conference system includes a server and a plurality of terminals, and the voice data transmitted from each terminal is synthesized by the server, and the synthesized voice data is distributed to each terminal.
Here, in the IP conference communication system, the network load can be reduced by multicast transmission of the audio data transmitted from the server to each terminal. However, each terminal needs to remove an echo generated when the voice data transmitted by the terminal is included in the voice data received from the server and returned.

  For echo cancellation, the server synthesizes voice data received from all terminals participating in the conference to generate one synthesized voice data, and multicasts the synthesized voice data to all terminals, while each terminal Has a method of removing and outputting the own voice data from the synthesized voice data received from the server (see, for example, Patent Document 1). According to this method, each terminal adds a terminal ID indicating a terminal type to a voice packet obtained by packetizing voice data to be transmitted to the server, and stores the transmitted voice data therein. The server synthesizes the voice data received from each terminal, adds the terminal ID of the voice synthesizer when packetizing the voice data and transmitting it to each terminal. When the terminal ID is included in the voice packet received from the server, each terminal removes the echo by subtracting the transmitted voice data stored therein from the received voice data.

Japanese Patent Laid-Open No. 10-164239

  In order to further reduce the network load related to voice packet transmission from the server to the terminal, it is also effective to reduce the amount of information by encoding voice data at a low bit rate. However, since encoding distortion occurs when low bit rate encoding is performed, there is a problem that echo cannot be removed by the method of subtracting audio data as in Patent Document 1 described above.

  The present invention has been made to solve the above-described problems, and even when audio data multicast-transmitted from the server to each terminal is encoded at a low bit rate, echo can be removed at the terminal. The purpose is to do.

  In the call conference according to the present invention, three or more terminals are divided into a high-priority terminal and a low-priority terminal, and for each high-priority terminal, the server is transmitted from a terminal other than the high-priority terminal to the server. The voice signal from the high priority terminal is selected from among the voice data transmitted from the high priority terminal to the server and the voice data transmitted from the low priority terminal to the server. The data is selected with priority, and the selected voice signal is transmitted by a multicast method together with selection information indicating whether the voice signal from the high priority terminal or the low priority terminal is selected. When receiving and playing back audio data transmitted by the method, while the effective audio data of its own terminal is being transmitted to the server, whether the received audio data is a high-priority terminal based on the selection information In which it was to be played if it is of sound data.

  In the call conference according to the present invention, three or more terminals are divided into a high-priority terminal and a low-priority terminal. The voice data transmitted from the high-priority terminal to the server and the voice data transmitted from the low-priority terminal to the server are multiplexed and transmitted to the low-priority terminal. However, when the low priority terminal receives and reproduces the voice data transmitted from the server by the multicast method, the low priority terminal transmits the valid voice data of its own terminal to the server. The voice data from the high priority terminal is played back.

  In the call conference according to the present invention, three or more terminals are divided into a high-priority terminal and a low-priority terminal, and for each high-priority terminal, the server is transmitted from a terminal other than the high-priority terminal to the server. The voice signal transmitted from the high-priority terminal to the server and the voice data transmitted from the low-priority terminal to the server are separately transmitted to the low-priority terminal using a multicast method. When a low-priority terminal receives and reproduces voice data transmitted from the server by multicast, the received voice data has high priority while it transmits valid voice data of its own terminal to the server. If it is audio data from the terminal, it is played back.

  According to this invention, the terminal is divided into a high-priority terminal and a low-priority terminal, and the server synthesizes and transmits voice data from other terminals excluding the terminal to the high-priority terminal. In response to the priority, the voice data from the high priority terminal is preferentially selected and multicast information is added to the selection information, and the low priority terminal transmits the valid voice data of its own terminal to the server. The audio data from the high-priority terminal included in the audio data received from is played back, and if the audio data from the low-priority terminal is included, it is not played back. Even if the signal is encoded at a low bit rate, no echo is detected at the terminal.

  According to this invention, the terminal is divided into a high-priority terminal and a low-priority terminal, and the server synthesizes and transmits voice data from other terminals excluding the terminal to the high-priority terminal. The voice data from the high-priority terminal and the voice data from the low-priority terminal are multiplexed and transmitted by multicast, and the low-priority terminal transmits the valid voice data of its own terminal to the server. The audio data received from the high priority terminal is reproduced and the audio data from the low priority terminal is not reproduced, so that the audio data multicast-transmitted from the server is encoded at a low bit rate. Even in such a case, no echo is detected at the terminal.

  According to this invention, the terminal is divided into a high-priority terminal and a low-priority terminal, and the server synthesizes and transmits voice data from other terminals excluding the terminal to the high-priority terminal. In response, the voice data from the high-priority terminal and the voice data from the low-priority terminal are separately multicast-transmitted, and the low-priority terminal transmits the valid voice data of its own terminal to the server from the server. The received voice data from the high priority terminal is played back, and the voice data from the low priority terminal is not played back, so even if the voice data multicast-transmitted from the server is encoded at a low bit rate, Is not perceived.

It is a block diagram which shows the structure of the telephone conference system which concerns on Embodiment 1 of this invention. 3 is a block diagram showing an internal configuration of a low priority terminal of the call conference system according to Embodiment 1. FIG. 3 is a block diagram showing an internal configuration of a high priority terminal of the call conference system according to Embodiment 1. FIG. It is a block diagram which shows the structure of the telephone conference system which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the telephone conference system which concerns on Embodiment 3 of this invention. FIG. 10 is a block diagram showing an internal configuration of a low priority terminal of a call conference system according to Embodiment 3. It is a block diagram which shows the structure of the telephone conference system which concerns on Embodiment 4 of this invention. It is a block diagram which shows the internal structure of the low priority terminal of the telephone conference system which concerns on Embodiment 4. It is a block diagram which shows the structure of the telephone conference system which concerns on Embodiment 5 of this invention. FIG. 10 is a block diagram showing an internal configuration of a low priority terminal of a call conference system according to Embodiment 5. It is a block diagram which shows the structure of the telephone conference system which concerns on Embodiment 6 of this invention. It is a block diagram which shows the internal structure of the low priority terminal of the telephone conference system which concerns on Embodiment 6. FIG. It is a block diagram which shows the structure of the telephone conference system which concerns on Embodiment 7 of this invention. FIG. 15 is a block diagram showing an internal configuration of a low priority terminal of a call conference system according to Embodiment 7.

Embodiment 1 FIG.
The call conference system shown in FIG. 1 has a configuration in which a conference is performed between one server and five terminals. In FIG. 1, a server 100 receives audio data transmitted from each terminal, synthesizes it, and transmits it to each terminal. Further, in the example of FIG. 1, two of the five terminals are set to high priority terminals 200a and 200b in which the priority of the conference call is set high, and the remaining three are set to have a low priority of the conference call. Low-priority terminals 300a to 300c.

The server 100 includes voice packet receivers 101 and 102 that receive voice packets transmitted from each terminal, a voice synthesizer 103 that synthesizes voice data, a voice packet transmitter 104 that packetizes and transmits voice data, An audio selection unit 105 that selects audio data to be transmitted by multicast transmission, an audio encoder 106 that encodes audio data at a low bit rate, a selection information addition unit 107 that adds audio data selection information, and packetizes the audio data A multicast voice packet transmitter 108 for multicast transmission and voice decoders 109a to 109c for decoding low bit rate encoded voice data are provided.
The number of speech decoders 109a to 109c is the same as the number of low priority terminals 300a to 300c.

The server 100 is composed of a CPU (Central Processing Unit) (not shown), and when the CPU executes a program stored in an internal memory, the voice packet receivers 101 and 102, the voice synthesizer 103, the voice Functions as the packet transmission unit 104, the voice selection unit 105, the voice encoder 106, the selection information addition unit 107, the multicast voice packet transmission unit 108, and the voice decoders 109a to 109c are realized.
In addition, some functions such as the speech encoder 106 and the speech decoders 109a to 109c may be configured by dedicated circuits.

Next, the operation of the server 100 will be described.
The high-priority terminals 200a and 200b and the low-priority terminals 300a to 300c packetize the voice data of their own terminals and transmit them to the server 100 as voice packets. Here, the payload of the voice packet transmitted by the high-priority terminals 200a and 200b, that is, the voice data is a PCM (Pulse Code Modulation) code that is not subjected to low bit rate coding. On the other hand, the payload of the voice packet transmitted by the low priority terminals 300a to 300c is voice data encoded with a low bit rate. Low bit rate coding is a bit rate lower than that of PCM, and refers to a coding method in which an audio signal decoded after encoding is not exactly the same as an audio signal before encoding (that is, encoding distortion is generated). .

In the server 100, the voice packet receiving unit 101 first receives a voice packet transmitted from the high priority terminals 200 a and 200 b, extracts the payload part of this voice packet, that is, the voice data of the PCM code, and sends it to the voice synthesis unit 103. Output.
On the other hand, the voice packet receiving unit 102 receives voice packets transmitted by the low priority terminals 300a to 300c, extracts the payload portion of the voice packets, that is, voice data of the low bit rate code, and outputs the voice decoders 109a to 109c. Output to. Speech decoders 109 a to 109 c decode the low bit rate code into a PCM code, and output it to speech synthesis section 103 and speech selection section 105.

The voice synthesizer 103 receives the voice data of the high priority terminals 200a and 200b output from the voice packet receiver 101 and the voice data of the low priority terminals 300a to 300c output from the voice decoders 109a to 109c. As voice data to be transmitted to either of the terminals 200a and 200b (voice data for high-priority terminal transmission), voice data obtained by synthesizing voice data from other than the terminal to be transmitted is generated, and is sent to the voice packet transmitting unit 104. Output.
That is, when transmitting to the high priority terminal 200a, the synthetic | combination audio | voice data which synthesize | combined the audio | voice data of the high priority terminal 200b and the low priority terminals 300a-300c are produced | generated. When transmitting to the high priority terminal 200b, the synthetic | combination audio | voice data which synthesize | combined the audio | voice data of the high priority terminal 200a and the low priority terminals 300a-300c are produced | generated.

  The voice packet transmission unit 104 packetizes voice data other than the high priority terminal 200 a input from the voice synthesis unit 103 and transmits the packetized data to the high priority terminal 200 a, and voice other than the high priority terminal 200 b input from the voice synthesis unit 103. Data is packetized and transmitted to the high priority terminal 200b.

  The voice synthesis unit 103 generates voice data obtained by synthesizing voice data of the high priority terminals 200a and 200b as voice data to be transmitted to the low priority terminals 300a to 300c (voice data for low priority terminal transmission). And output to the voice selection unit 105.

The voice selection unit 105 includes voice data (high-priority terminal transmission voice data) output from the voice synthesis unit 103 and low-priority terminals 300a to 300c output from the voice decoders 109a to 109c. Audio data is input, and one of them is selected and output to the audio encoder 106. The selection gives priority to voice data for low-priority terminal transmission input from the voice synthesizer 103, that is, synthesized voice data of the high-priority terminals 200a and 200b.
Further, 0 is output to the selection information addition unit 107 from the voice selection unit 105 as selection information when the voice data input from the voice synthesis unit 103 is selected, and 1 otherwise.

As a specific selection method, first, the voice selection unit 105 detects the voice / silence of each voice data input, and if the voice data input from the voice synthesis unit 103 is voiced, always Select audio data. In addition, the voice selection unit 105 selects the voice data of the voice synthesis unit 103 even when all the voice data input from the voice synthesis unit 103 and the voice decoders 109a to 109c are silent. The voice selection unit 105 selects the voice data if only one of the voice data input from the voice synthesis unit 103 and the voice decoders 109a to 109c is voiced.
In addition, the voice selection unit 105 first determines that the voice data input from the voice synthesis unit 103 is silent and two or more of the voice data input from the voice decoders 109a to 109c are voiced. Select voice data that has sound.

The speech encoder 106 performs low bit rate coding on the speech data input from the speech selection unit 105 and outputs the speech data of the low bit rate code to the selection information addition unit 107.
The selection information adding unit 107 adds 0 or 1 selection information input from the audio selection unit 105 to the low bit rate code audio data input from the audio encoder 106, and sends it to the multicast audio packet transmission unit 108. Output.
The multicast voice packet transmission unit 108 packetizes the low bit rate code voice data and selection information input from the selection information adding unit 107, and multicasts them to the low priority terminals 300a to 300c.

  Next, the operation of the low priority terminals 300a to 300c will be described with reference to FIG. Although FIG. 2 is a block diagram showing the internal configuration of the low priority terminal 300a, the low priority terminals 300b and 300c have the same configuration.

The low-priority terminal 300a includes, as functions related to transmission, a microphone 301 that collects speech spoken by a terminal user, an A / D converter 302 that converts analog speech input from the microphone 301 into a PCM code, and a PCM code. A speech encoder 304 for low-bit-rate encoding the speech data, and a speech packet transmission unit 305 for packetizing and transmitting the speech data of the low bit-rate code.
Further, the low priority terminal 300a separates selection information added to the voice data of the received multicast voice packet from the multicast voice packet receiving unit 306 that receives the multicast voice packet transmitted by the server 100 as a function related to reception. A selection information separation unit 307; a speech decoder 308 that decodes received speech data from a low bit rate code to a PCM code; a speech detection unit 303 that determines the presence / absence of speech of a terminal user; A switch 309 that switches output of audio data, a D / A converter 310 that converts PCM codes into analog audio, and a speaker 311 that outputs analog audio are provided.

  The low-priority terminal 300a is composed of a CPU (not shown), and when the CPU executes a program stored in an internal memory, a voice detection unit 303, a voice packet transmission unit 305, a multicast voice packet reception unit A function as the selection information separation unit 307 and the like is realized. Further, some functions such as the A / D converter 302, the D / A converter 310, the speech encoder 304, the speech decoder 308, and the switch 309 may be configured by a dedicated circuit.

In the low-priority terminal 300 a, the user's voice is collected by the microphone 301, converted to a PCM code by the A / D converter 302, and then input to the sound detection unit 303 and the voice encoder 304.
The sound detection unit 303 determines whether the input voice data of the PCM code is sound or sound, and outputs 1 to the switch 309 if sound is present and 0 if sound is not present.
The voice encoder 304 performs low bit rate coding on the PCM code input from the voice detection unit 303, and outputs the voice data of the low bit rate code to the voice packet transmission unit 305.
The voice packet transmission unit 305 packetizes the voice data of the low bit rate code input from the voice encoder 304 and transmits the packetized data to the server 100.

  The multicast voice packet receiving unit 306 receives the multicast voice packet from the server 100, extracts the payload portion of the packet, and outputs it to the selection information separation unit 307. As described in the operation description of the server 100, this payload part is data in which 0 or 1 selection information is added to the audio data of the low bit rate code, and the selection information separation unit 307 separates this, The audio data of the low bit rate code is output to the audio decoder 308 and the selection information is output to the switch 309.

The audio decoder 308 decodes the audio data of the low bit rate code input from the selection information separation unit 307 into a PCM code, and outputs it to the switch 309.
The switch 309 performs D / A conversion on the PCM code input from the speech decoder 308 when either the input from the selection information separation unit 307 and the input from the sound detection unit 303 are 0 or both are 0. Output to the device 310. On the other hand, when both the input from the selection information separation unit 307 and the input from the voice detection unit 303 are 1, the switch 309 does not output the PCM code input from the speech decoder 308, and does not output the silent PCM code. The data is output to the D / A converter 310.
The D / A converter 310 converts the PCM code input from the switch 309 into analog voice and outputs the analog voice to the user via the speaker 311.

  Next, the operation of the high priority terminals 200a and 200b will be described with reference to FIG. Although FIG. 3 is a block diagram showing the internal configuration of the high priority terminal 200a, the high priority terminal 200b has the same configuration. The high priority terminal 200a packetizes the microphone 201 that collects the voice spoken by the terminal user, the A / D converter 202 that converts the analog voice input from the microphone 201 into the PCM code, and the voice data of the PCM code. A voice packet transmission unit 203 that transmits to the server 100, a voice packet reception unit 204 that receives a voice packet transmitted from the server 100, and a D / A converter that converts voice data included in the received voice packet into analog voice 205 and a speaker 206 for outputting analog sound.

  In this call conference system, when the server 100, the high-priority terminals 200a and 200b, and the low-priority terminals 300a to 300c operate as described above, any of the low-priority terminals 300a to 300c is included in the voice packets that the server 100 performs multicast transmission. When the voice data transmitted to the server 100 is included, since the selection information in the voice packet is 1, the selection information separation unit 307 inputs to the switch 309 in the low priority terminals 300a to 300c. 1 When the user of the low-priority terminals 300a to 300c is speaking, the input from the voice detection unit 303 to the switch 309 is also 1 at the terminal, so the switch 309 of the terminal converts the silent PCM code to D / A Output to the converter 310. Therefore, even if the multicast voice packet received by the low priority terminals 300a to 300c includes the voice data transmitted by the low priority terminals 300a to 300c, the multicast voice packet is not reproduced and the occurrence of echo can be prevented.

  However, the user of any one of the low priority terminals 300a to 300c may miss the voice of another low priority terminal. For example, when the users of the low priority terminals 300a and 300b speak at the same time and the voice data of the low priority terminal 300a is included in the multicast voice packet transmitted by the server 100, the user of the low priority terminal 300b is low priority. The voice of the terminal 300a is missed.

  On the other hand, when the voice data included in the multicast voice packet transmitted by the server 100 is the voice data of the high priority terminals 200a and 200b, the selection information to be added is 0, so each of the low priority terminals 300a to 300c. The user never misses.

In addition, each user of the high priority terminals 200a and 200b does not miss the sound from any other terminal without being reproduced, and all the spoken sounds are reproduced on all terminals.
Further, the voice packet transmitted from the server 100 to the high priority terminal 200a does not include the voice data of the high priority terminal 200a, and the voice packet transmitted from the server 100 to the high priority terminal 200b includes the high priority terminal 200b. Is not included, so echo can be prevented.

This call conference system assumes that the conference moderator uses the high-priority terminals 200a and 200b, and other general conference participants use the low-priority terminals 300a to 300c.
The presenter can surely hear the voices of all the conference participants, and each conference participant can hear the voices of the presenter reliably. In addition, the user of any terminal does not hear an echo generated when his / her voice returns via the server 100.

  As described above, according to the first embodiment, three or more terminals are divided into a high priority terminal and a low priority terminal, and the server receives voice data from other terminals other than the terminal for the high priority terminal. The low-priority terminal selects the voice data from the high-priority terminal with priority and sends the selection information to the multicast, and the low-priority terminal transmits the valid voice data of its own terminal. Is transmitted to the server based on the selection information, if the audio data received from the server contains audio data from the low priority terminal, it will not be played back. Even when data is encoded at a low bit rate, it is possible to obtain a telephone conference system that does not sense echo at the terminal.

  Further, according to the first embodiment, the low-priority terminal detects the presence and absence of the voice data of its own terminal, and determines that the voice data in which the voice is detected is transmitted to the server as valid voice data. I tried to do it. With this operation, the low-priority terminal does not reproduce the voice data of the low-priority terminal received from the server only when the user speaks and the terminal is in a voiced state (that is, when valid voice data is transmitted). . Therefore, when the user is not speaking and the terminal is silent, the voice data from other low priority terminals can be reproduced.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing the configuration of the call conference system according to the second embodiment. The server 100 newly includes a reception-side voice synthesis unit 121 that synthesizes voice data received from the low-priority terminals 300a to 300c. I have.
The internal configurations of the high priority terminals 200a and 200b and the low priority terminals 300a to 300c are the same as those shown in FIGS.

Next, the operation of the server 100 according to the second embodiment will be described.
4, operations of the voice packet receiving units 101 and 102, the voice packet transmitting unit 104, the voice encoder 106, the selection information adding unit 107, the multicast voice packet transmitting unit 108, and the voice decoders 109a to 109c of the server 100 are shown in FIG. 1 is the same as that in the first embodiment described above. The operations of the high priority terminals 200a and 200b and the low priority terminals 300a to 300c are the same as those in the first embodiment described with reference to FIGS.

  The reception side speech synthesizer 121 synthesizes the speech data input from the speech decoders 109 a to 109 c and outputs the synthesized speech data to the speech synthesizer 103 and the speech selector 105.

The operation of the speech synthesizer 103 is the same as that of the speech synthesizer 103 of the server 100 shown in FIG. 1 except that the input speech data is reduced.
First, the voice synthesis unit 103 generates voice data for high-priority terminal transmission by synthesizing voice data other than that terminal for either the high-priority terminal 200a or the high-priority terminal 200b. To 104. That is, for the high-priority terminal 200a, the voice data from the high-priority terminal 200b and the reception-side voice synthesis unit 121 is synthesized, and for the high-priority terminal 200b, the high-priority terminal 200a and the reception-side voice synthesis unit 121 are synthesized. Synthesize audio data from
Furthermore, the voice selection unit 105 generates voice data for low-priority terminal transmission by combining voice data from the high-priority terminals 200 a and 200 b and outputs the voice data to the voice selection unit 105.

The operation of the voice selection unit 105 is the same as that of the voice selection unit 105 of the server 100 illustrated in FIG. 1 except that less voice data is input.
First, the speech selection unit 105 selects any of the speech data input from the speech synthesis unit 103 and the reception side speech synthesis unit 121 and outputs the selected speech data to the speech encoder 106. The selection gives priority to voice data for low-priority terminal transmission input from the voice synthesizer 103, that is, synthesized voice data of the high-priority terminals 200a and 200b.
As a specific selection method, first, the voice selection unit 105 detects the presence / absence of voice data input, and if the voice data input from the voice synthesis unit 103 is voiced, always Voice data is selected, and voice data from the voice synthesizer 103 is selected even when both voice data are silent. In addition, the voice selection unit 105 selects the voice data from the reception-side voice synthesis unit 121 when only the voice data input from the reception-side voice synthesis unit 121 is voiced.
Then, the voice selection unit 105 outputs 0 to the selection information addition unit 107 when the voice data input from the voice synthesis unit 103 is selected and 1 otherwise.

  When the server 100, the high priority terminals 200a and 200b, and the low priority terminals 300a to 300c operate as described above, the low priority terminals 300a to 300b are included in the voice packets that the server 100 performs multicast transmission, as in the first embodiment. When any of 300c includes voice data transmitted to the server 100, since the selection information in the voice packet is 1, the selection information separation unit in the low priority terminals 300a to 300c shown in FIG. The input from 307 to the switch 309 is 1. While the user of the low-priority terminals 300a to 300c is speaking, the input from the voice detection unit 303 to the switch 309 is also 1 at the terminal, so the switch 309 of the terminal converts the silence to the D / A converter 310. Output to. Therefore, even if the multicast voice packet received by the low priority terminals 300a to 300c includes the voice data transmitted by the low priority terminals 300a to 300c, the multicast voice packet is not reproduced and the occurrence of echo can be prevented.

  As described above, according to the second embodiment, three or more terminals are divided into a high priority terminal and a low priority terminal, and the server receives voice data from other terminals excluding the terminal for the high priority terminal. The low-priority terminal selects the voice data from the high-priority terminal with priority and also adds the selection information for multicast transmission. The low-priority terminal has the transmission voice of its own terminal. During sound, based on the selection information, if the audio data received from the server contains audio data from the low priority terminal, the operation is performed so that the audio data multicast-transmitted from the server has a low bit rate. It is possible to obtain a telephone conference system that does not detect echoes at the terminal even if it is encoded.

  Further, according to the second embodiment, the server transmits the voice data transmitted from the plurality of low priority terminals to the server as the voice data from the low priority terminal included in the voice data transmitted to the low priority terminal by the multicast method. The synthesized data was used. Thus, the speech selection unit 105 only needs to select either the speech data of the reception side speech synthesizer 121 or the speech data from the speech synthesizer 103, and the speech data from the speech decoders 109a to 109c can be individually selected. The processing is reduced compared to the case of inputting and selecting.

Embodiment 3 FIG.
FIG. 5 is a block diagram showing the configuration of the call conference system according to Embodiment 3, in which server 100 newly receives a control packet receiving unit 131 that receives control packets from low priority terminals 300a to 300c, and low priority. A speech reception control unit 132 that determines whether or not speech permission requested by the terminals 300a to 300c is requested, and a control packet transmission unit 133 that transmits a control packet to the low priority terminals 300a to 300c. In the first and second embodiments, the speech decoder 109 common to the low priority terminals is provided instead of the speech decoders 109a to 109c provided for each low priority terminal.

Next, the operation of the server 100 according to the third embodiment will be described.
In FIG. 5, the operations of the voice packet receiving units 101 and 102, the voice packet transmitting unit 104, the voice encoder 106, the selection information adding unit 107, and the multicast voice packet transmitting unit 108 of the server 100 are the same as those described in FIG. This is the same as the first embodiment. The operations of the voice synthesis unit 103 and the voice selection unit 105 are the same as those in the second embodiment described with reference to FIG.
The operations of the high priority terminals 200a and 200b are the same as those in the first embodiment described with reference to FIG.

Although details will be described later, the low-priority terminals 300a to 300c according to the second embodiment transmit a control packet for requesting permission to speak to the server 100 when the user of the terminal itself speaks. Here, the description will be made on the assumption that the low priority terminal 300a has transmitted a control packet for requesting permission to speak.
In the server 100, the control packet receiving unit 131 receives the control packet for requesting the speech permission, and notifies the speech reception control unit 132 of the reception of the control packet.

  Upon receiving the notification from the control packet receiving unit 131, the speech reception control unit 132 determines whether or not to allow the user of the low-priority terminal 300a that has transmitted this control packet, and the determination result is the control packet transmission unit 133. Notify Here, when there is a request for permission to speak from a plurality of low-priority terminals, the speech reception control unit 132 determines that only one of the terminals is permitted to speak.

The control packet transmission unit 133 notifies the control packet that notifies the speech permission when the speech acceptance control unit 132 is notified of the determination result that permits the speech, and rejects the speech when the determination result that does not permit the speech is notified. The control packet to be notified is transmitted to the requesting low priority terminal 300a.
In addition, the speech reception control unit 132 notifies the voice packet reception unit 102 of the determination result.

  As will be described in detail later, when the low priority terminal 300a that has requested permission to speak receives a control packet that notifies the permission of speaking, the low priority terminal 300a starts transmitting a voice packet including voice data spoken by the user, and the user's speech ends. Transmission of the voice packet is stopped, and a control packet for notifying completion of the speech is transmitted to the server 100.

In the server 100, the voice packet receiving unit 102 receives only the voice packet from the low priority terminal 300 a that is allowed to speak according to the determination result of the message reception control unit 132, and the payload portion (that is, low The bit rate code audio data) is extracted and output to the audio decoder 109.
The voice decoder 109 decodes the low bit rate code voice data input from the voice packet receiver 102 into a PCM code and outputs the PCM code to the voice synthesizer 103 and the voice selector 105.

  Further, the control packet receiving unit 131 receives a control packet for notifying the completion of the message from the low priority terminal 300a, and notifies the message reception control unit 132 of the reception of this packet. Thereby, the speech reception control unit 132 recognizes the completion of the speech of the low priority terminal 300a that has permitted the speech, notifies the control packet transmission unit 133 of the response instruction, and notifies the voice packet reception unit 102 of the completion of the speech. .

When receiving a response instruction from the message reception control unit 132, the control packet transmission unit 133 transmits a control packet indicating that the message completion notification has been received to the low priority terminal 300a that is the transmission source of the message completion notification.
In addition, when the voice packet receiving unit 102 receives the notification of the completion of the speech from the speech admission control unit 132, the voice packet receiving unit 102 stops the voice packet receiving operation from the low priority terminals 300a to 300c, and outputs voice data to the voice decoder 109. Stop.

  The voice decoder 109 outputs silence to the voice synthesizer 103 and the voice selector 105 when the input of voice data from the voice packet receiver 102 stops. Note that the operation of the speech decoder 109 is basically the same as the operation of the speech decoders 109a to 109c shown in FIG. 1, and only the operation of outputting silence is added.

Next, the operation of the low priority terminals 300a to 300c according to the third embodiment will be described with reference to FIG.
FIG. 6 is a block diagram showing an internal configuration of the low priority terminal 300a according to the third embodiment. The low priority terminal 300a is newly added to the talk switch 331 and the server 100 that the user of the own terminal presses when speaking. A control packet transmission unit 332 that transmits a control packet, a control packet reception unit 333 that receives a control packet from the server 100, and a speech permission lamp 334 that displays whether or not the user's speech of the terminal is permitted. It has.

In FIG. 6, the microphone 301, the A / D converter 302, the voice detection unit 303, the voice encoder 304, the voice packet transmission unit 305, the multicast voice packet reception unit 306, the selection information separation unit 307, and the voice decoder 308. The operations of the switch 309, the D / A converter 310, and the speaker 311 are the same as those in the first embodiment described with reference to FIG.
The internal configuration of the low priority terminals 300b and 300c is the same as that in FIG.
The operations of the high priority terminals 200a and 200b are the same as those in the first embodiment described with reference to FIG.

In the low priority terminal 300a, the talk switch 331 is pressed when the terminal user speaks. The talk switch 331 outputs the pressed state to the control packet transmission unit 332.
When the talk switch 331 changes from the non-pressed state to the pressed state when the low-priority terminal 300a is not currently in the speech-permitted state when the low-priority terminal 300a is not in the speech-permitted state, the control packet transmission unit 332 generates a control packet that requests speech permission. Send. On the other hand, when the talk switch 331 returns from the pressed state to the non-pressed state when the low-priority terminal 300a is currently in the speech-permitted state, the control packet transmission unit 332 generates a control packet for notifying the completion of the speech, To 100.
Whether or not the low-priority terminal 300a is in the speech-permitted state is obtained from an output from the control packet receiving unit 333, which will be described later.

  Based on the control packet received from the server 100, the control packet receiving unit 333 determines whether or not the terminal is in the speech-permitted state. If the terminal is in the speech-permitted state, 1 is transmitted, otherwise 0 is transmitted. Unit 332, voice packet transmission unit 305, switch 309, and speech permission lamp 334.

  The speech permission state is determined as follows. First, the initial state is a state where speech is not permitted. When the control packet receiving unit 333 receives a control packet for notifying speech permission from the server 100 in a state where speech is not permitted, the control packet receiving unit 333 changes to the speech permitted state, and receives a speech completion notification from the server 100 when in the speech permitted state. When a control packet indicating that the message has been received is received, the state returns to a state where speech is not permitted.

The speech permission lamp 334 is turned on when the output of the control packet receiving unit 333 is 1, that is, the speech permitted state, and is turned off when the output of the control packet receiving unit 333 is 0.
The user of the low-priority terminal 300a recognizes whether or not he / she can speak by seeing whether the speech permission lamp 334 is turned on / off.

  When the output of the control packet receiver 333 is 1, that is, when the speech is permitted, the voice packet transmitter 305 packetizes the low bit rate code voice data input from the voice encoder 304 and transmits the packet to the server 100.

  The switch 309 performs D / A conversion on the PCM code input from the speech decoder 308 when either the input from the selection information separation unit 307 and the input from the control packet reception unit 333 are 0 or both are 0. Output to the device 310. On the other hand, when both the input from the selection information separation unit 307 and the input from the control packet reception unit 333 are 1, the switch 309 does not output the PCM code audio data input from the audio decoder 308 and does not output silence. The data is output to the D / A converter 310.

  When the server 100, the high-priority terminals 200a and 200b, and the low-priority terminals 300a to 300c operate as described above, while the user of the low-priority terminals 300a to 300c who is allowed to speak is speaking, the control packet receiving unit 333 switches to the switch 309. Is added when the voice data transmitted to the server 100 by one of the low priority terminals 300a to 300c is included in the multicast voice packet received by the multicast voice packet receiving unit 306. Since the selection information is 1, silence is output from the switch 309 to the D / A converter 310. Therefore, even if the multicast voice packet received by the low priority terminals 300a to 300c includes the voice data transmitted by the low priority terminals 300a to 300c, the multicast voice packet is not reproduced and the occurrence of echo can be prevented.

In addition, since any one of the low priority terminals 300a to 300c allowed to speak is one terminal, the user of the low priority terminal permitted to speak does not miss the voice of other low priority terminals. It is superior to the call conference system of the first and second embodiments.
Furthermore, since the voice packets of the plurality of low priority terminals 300a to 300c are not transmitted simultaneously, the load on the network is further reduced.

  As described above, according to the third embodiment, three or more terminals are divided into a high priority terminal and a low priority terminal, and the server receives voice data from other terminals other than the terminal for the high priority terminal. The low-priority terminal selects the voice data from the high-priority terminal with priority and sends the selection information to the multicast, and the low-priority terminal transmits the valid voice data of its own terminal. Is transmitted to the server based on the selection information, if the audio data received from the server contains audio data from the low priority terminal, it will not be played back. Even when data is encoded at a low bit rate, it is possible to obtain a telephone conference system that does not sense echo at the terminal.

  Further, according to the third embodiment, the server permits or disallows the speech of the user of the low-priority terminal, and the low-priority terminal transmits the user's speech when receiving permission from the server for the user of the local terminal. Was sent to the server as valid voice data. At this time, by setting the number of low-priority terminals that the server permits to speak to only one terminal, it is possible to prevent a plurality of low-priority terminals from simultaneously transmitting voice data to the server, and to further reduce the network load.

  Further, according to the third embodiment, the server transmits the speech data from the low priority terminal permitted to speak to the server as the voice data from the low priority terminal included in the voice data transmitted to the low priority terminal by the multicast method. Audio data was used. At this time, it is possible to prevent the low-priority terminal from missing the speech of other low-priority terminals by setting the low-priority terminal that the server permits to speak to only one terminal.

Embodiment 4 FIG.
FIG. 7 is a block diagram showing a configuration of a call conference system according to Embodiment 4, in which server 100 newly encodes audio data received from low priority terminals 300a to 300c at a low bit rate. 141, a multicast voice packet transmission unit 142 that packetizes voice data encoded at a low bit rate and multicasts it. Further, instead of the speech synthesizer 103 of the first and second embodiments, a speech synthesizer 143 having a partially different operation is provided.

  The server 100 of the fourth embodiment has two multicast voice packet transmission units 108 and 142. One multicast voice packet transmission unit 108 synthesizes voice data of the high-priority terminals 200a and 200b and generates a low bit. The other multicast voice packet transmitting unit 142 is for transmitting rate-coded multicast voice packets. The other multicast voice packet transmitting unit 142 synthesizes voice data of the low-priority terminals 300a to 300c and low-rate encoded multicast voice packets. It is for sending.

The operation of the server 100 according to the fourth embodiment will be described below.
7, the operations of the voice packet receiving units 101 and 102, the voice packet transmitting unit 104, the voice encoder 106, the multicast voice packet transmitting unit 108, and the voice decoders 109a to 109c of the server 100 are the same as those described with reference to FIG. This is the same as the first embodiment. The operation of the multicast voice packet transmission unit 108 is not the low bit rate code voice data to which the selection information is added but the packet data of the low bit rate code voice data to which the selection information is not added. This is the same as the first embodiment described above. Further, the operation of the reception side speech synthesizer 121 is the same as that of the second embodiment described with reference to FIG.

The speech encoder 141 performs low bit rate coding on the PCM code input from the reception side speech synthesis unit 121, and outputs speech data of the low bit rate code to the multicast speech packet transmission unit 142.
The multicast voice packet transmission unit 142 packetizes the low bit rate code voice data input from the voice encoder 141, and multicasts the voice data to the low priority terminals 300a to 300c.
That is, the sequence composed of the voice encoder 141 and the multicast voice packet transmission unit 142 is to multicast the voice data received from the low priority terminals 300a to 300c to the low priority terminals 300a to 300c.

The voice synthesizer 143 receives the voice data of the high priority terminals 200a and 200b output from the voice packet receiver 102 and the voice data of the low priority terminals 300a to 300c output from the receiver voice synthesizer 121, and receives high priority. As voice data to be transmitted to either terminal 200 a or 200 b, voice data from other than the terminal to be transmitted is synthesized and output to voice packet transmitting section 104.
This operation is the same as that of the speech synthesizer 103 shown in FIG.

The voice synthesizer 143 synthesizes voice data of the high priority terminals 200 a and 200 b output from the voice packet receiver 102 and outputs the synthesized voice data to the voice encoder 106. The voice data is encoded at a low bit rate in the voice encoder 106 and multicast transmitted from the multicast voice packet transmission unit 108 to the low priority terminals 300a to 300c.
That is, the sequence composed of the voice encoder 106 and the multicast voice packet transmitting unit 108 multicasts voice data received from the high priority terminals 200a and 200b to the low priority terminals 300a to 300c.

Next, the operation of the low priority terminals 300a to 300c of the fourth embodiment will be described with reference to FIG.
FIG. 8 is a block diagram showing the internal configuration of the low priority terminal 300a according to the fourth embodiment. The low priority terminal 300a is a multicast voice packet that newly includes voice data from the low priority terminals 300a to 300c. Multicast voice packet receiving unit 341 for receiving voice data from server 100, voice decoder 342 for decoding voice data of low bit rate code from low priority terminals 300a to 300c, voice data from high priority terminals 200a and 200b, and low priority terminals A speech synthesis unit 343 that synthesizes speech data from 300a to 300c is provided.

In FIG. 8, a microphone 301, an A / D converter 302, a voice detection unit 303, a voice encoder 304, a voice packet transmission unit 305, a multicast voice packet reception unit 306, a voice decoder 308, a switch 309, a D / D The operations of the A converter 310 and the speaker 311 are the same as those in the first embodiment described with reference to FIG.
The internal configurations of the low priority terminals 300b and 300c are the same as those in FIG.
The operations of the high priority terminals 200a and 200b are the same as those in the first embodiment described with reference to FIG.

  In the low priority terminal 300a, the multicast voice packet receiving unit 306 receives a multicast voice packet including the voice data of the high priority terminals 200a and 200b (packet transmitted by the multicast voice packet transmitting unit 108 of the server 100), and its payload part. That is, the audio data of the low bit rate code is extracted and output to the audio decoder 308.

On the other hand, the multicast voice packet receiving unit 341 receives a multicast voice packet including the voice data of the low priority terminals 300a to 300c (the packet transmitted by the multicast voice packet transmitting unit 142 of the server 100), and its payload part, that is, a low level. The audio data of the bit rate code is extracted and output to the audio decoder 342.
The audio decoder 342 decodes the low bit rate code audio data of the low priority terminals 300 a to 300 c into the PCM code and outputs the PCM code to the switch 309.
The switch 309 outputs the PCM code speech data input from the speech decoder 342 to the speech synthesizer 343 when the output of the speech detector 303 is 0, and the output of the speech detector 303 is 1. Do not output in case.

  The voice synthesis unit 343 synthesizes the voice data of the high priority terminals 200a and 200b input from the voice decoder 308 and the voice data of the low priority terminals 300a to 300c input from the switch 309, and performs D / A conversion. Output to the device 310. Here, when there is no input from the switch 309, only the input from the speech decoder 308 is output to the D / A converter 310.

  When the server 100, the high-priority terminals 200a and 200b, and the low-priority terminals 300a to 300c operate as described above, while the user of the low-priority terminals 300a to 300c is speaking, the voice detection unit 303 switches to the switch 309 at that terminal. The switch 309 outputs a silent PCM code to the speech synthesizer 343. Therefore, even if the voice data transmitted by itself is included in the multicast voice packet received by the multicast voice packet receiver 341 of the low-priority terminals 300a to 300c, it is not reproduced and echo can be prevented. .

  As described above, according to the fourth embodiment, three or more terminals are divided into a high priority terminal and a low priority terminal, and the server receives voice data from other terminals other than the terminal for the high priority terminal. The voice data from the high-priority terminal and the voice data from the low-priority terminal are separately multicast-transmitted to the low-priority terminal. Since the operation is performed so as not to reproduce the voice data from the low-priority terminal received from the server, the terminal can detect an echo even when the voice data multicast-transmitted from the server is encoded at a low bit rate. You can get no call conferencing system.

Embodiment 5. FIG.
FIG. 9 is a block diagram showing a configuration of a call conference system according to the fifth embodiment.
9, the operations of the voice packet receiving unit 101, the voice packet transmitting unit 104, the voice encoder 106, and the multicast voice packet transmitting unit 108 of the server 100 are the same as those in the first embodiment described with reference to FIG. The operations of the voice packet receiving unit 102, the voice decoder 109, the control packet receiving unit 131, the message reception control unit 132, and the control packet transmission unit 133 are the same as those in the third embodiment described with reference to FIG. The operations of the multicast voice packet transmitting unit 142 and the voice synthesizing unit 143 are the same as those in the fourth embodiment described with reference to FIG.

  The operations of the high priority terminals 200a and 200b are the same as those in the first embodiment described with reference to FIG.

  In the server 100, the multicast voice packet transmitting unit 142 packetizes the low bit rate code voice data input from the voice packet receiving unit 102, and multicasts the voice data to the low priority terminals 300a to 300c. Here, when the voice packet is not received from any of the low priority terminals 300a to 300c, there is no output of the voice packet receiving unit 102, and therefore the multicast voice packet is not transmitted from the multicast voice packet transmitting unit 142.

Next, the operation of the low priority terminals 300a to 300c according to the fifth embodiment will be described with reference to FIG. FIG. 10 is a block diagram showing an internal configuration of the low priority terminal 300a according to the fifth embodiment. 10, the operations of the microphone 301, the A / D converter 302, the voice encoder 304, the voice packet transmission unit 305, the voice decoder 308, the D / A converter 310, and the speaker 311 are the same as those described in FIG. This is the same as the first embodiment. The operations of the talk switch 331, the control packet transmitter 332, the control packet receiver 333, and the speech permission lamp 334 are the same as those in the third embodiment described with reference to FIG. The operations of the switch 309 and the multicast voice packet receiving unit 306 are the same as those in the fourth embodiment described with reference to FIG.
The internal configuration of the low priority terminals 300b and 300c is the same as that shown in FIG.

The operations of the multicast voice packet receiving unit 341 and the voice decoder 342 are basically as described with reference to FIG.
The multicast voice packet receiving unit 341 that has received a multicast voice packet including the voice data of the low-priority terminals 300a to 300c (the packet transmitted by the multicast voice packet transmitting unit 142 of the server 100) receives the payload portion, that is, the low bit rate code. The audio data is extracted and output to the audio decoder 342, and the audio decoder 342 decodes the low bit rate code into a PCM code and outputs the PCM code to the switch 309.
However, as described above, a multicast voice packet may not be transmitted from the multicast voice packet transmitter 142 of the server 100. In this case, there is no output from the multicast voice packet receiver 341 to the voice decoder 342, and the voice decoder 342 is not transmitted. Outputs a silent PCM code to the switch 309.

When the server 100, the high-priority terminals 200a and 200b, and the low-priority terminals 300a to 300c operate as described above, while the user of the low-priority terminals 300a to 300c who is allowed to speak is speaking, the control packet receiving unit 333 switches to the switch 309. Is 1 and silence is output from the switch 309 to the speech synthesizer 343. Therefore, the audio of the low priority terminals 300a to 300c is not reproduced from the speaker 311 and the occurrence of echoes can be prevented.
Further, since any one of the low-priority terminals 300a to 300c permitted to speak is used, the user of the low-priority terminal permitted to speak does not miss the voice of the other low-priority terminals.

  As described above, according to the fifth embodiment, three or more terminals are divided into a high priority terminal and a low priority terminal, and the server receives voice data from other terminals other than the terminal for the high priority terminal. The voice data from the high-priority terminal and the voice data from the low-priority terminal are separately multicast-transmitted to the low-priority terminal. While transmitting data, it operates so as not to reproduce the audio data from the low priority terminal received from the server, so even if the audio data multicast transmitted from the server is encoded at a low bit rate, It is possible to obtain a call conference system that does not sense the call.

Embodiment 6 FIG.
FIG. 11 is a block diagram showing the configuration of the call conference system according to the sixth embodiment. The server 100 newly includes a voice code multiplexing unit 161 that multiplexes voice data of two types of low bit rate codes. Yes.
In FIG. 11, the operations of the voice packet receiving units 101 and 102, the voice packet transmitting unit 104, the voice encoder 106, and the voice decoders 109a to 109c of the server 100 are the same as those in the first embodiment described with reference to FIG. is there. The operation of the reception side speech synthesizer 121 is the same as that of the second embodiment described with reference to FIG. The operations of the speech encoder 141 and speech synthesis unit 143 are the same as those in the fourth embodiment described with reference to FIG.

  The operations of the high priority terminals 200a and 200b are the same as those in the first embodiment described with reference to FIG.

  In the server 100, the speech code multiplexing unit 161 includes low bit rate code speech data of the high priority terminals 200 a and 200 b input from the speech encoder 106 and low priority terminals 300 a to 300 c input from the speech encoder 141. The voice data of the low bit rate code is multiplexed, and the multiplexed data is output to the multicast voice packet transmitter 108. In multiplexing, the low bit rate code input from the speech encoder 141 is always placed after the low bit rate code input from the speech encoder 106.

  The speech encoder 106 encodes speech data from the high priority terminals 200a and 200b at a low bit rate, and the speech encoder 141 encodes speech data from the low priority terminals 300a to 300c at a low bit rate. Therefore, the multiplexed data output from the voice code multiplexer 161 is low bit rate code voice data of the high priority terminals 200a and 200b in the first half, and low bit rate code voice of the low priority terminals 300a to 300c in the second half. The data is multiplexed data.

  The multicast voice packet transmission unit 108 packetizes the multiplexed data input from the voice code multiplexing unit 161, and multicasts the data to the low priority terminals 300a to 300c.

Next, the operation of the low priority terminals 300a to 300c of the sixth embodiment will be described with reference to FIG. FIG. 12 is a block diagram showing an internal configuration of the low priority terminal 300a according to Embodiment 6. The low priority terminal 300a newly adds a voice code separation unit 361 that separates multiplexed data in a multicast voice packet. It has.
In FIG. 12, the operations of the microphone 301, A / D converter 302, voice detection unit 303, speech encoder 304, speech packet transmission unit 305, speech decoder 308, D / A converter 310, and speaker 311 are illustrated. This is the same as the first embodiment described in the second embodiment. The operations of speech decoder 342, speech synthesizer 343, and switch 309 are the same as those in the fourth embodiment described with reference to FIG.
The internal configuration of the low priority terminals 300b and 300c is the same as that shown in FIG.

  In the low-priority terminal 300a, the multicast voice packet receiving unit 306 receives the multicast voice packet transmitted by the server 100, extracts the payload portion, and outputs it to the voice code separation unit 361. The payload portion is multiplexed data as described above, and the speech code separation unit 361 outputs the speech data of the low bit rate code of the high priority terminals 200a and 200b in the first half of the multiplexed data to the speech decoder 308, The audio data of the low bit rate code of the latter low priority terminals 300 a to 300 c is output to the audio decoder 342.

  When the server 100, the high-priority terminals 200a and 200b, and the low-priority terminals 300a to 300c operate as described above, while the user of the low-priority terminals 300a to 300c is speaking, the voice detection unit 303 switches to the switch 309 at that terminal. The switch 309 outputs a silent PCM code to the speech synthesizer 343. Therefore, the voice data of the low priority terminals 300a to 300c multiplexed in the second half of the multicast voice packet is not reproduced, and the occurrence of echo can be prevented.

  As described above, according to the sixth embodiment, three or more terminals are divided into a high priority terminal and a low priority terminal, and the server receives voice data from other terminals other than the terminal for the high priority terminal. The voice data from the high-priority terminal and the voice data from the low-priority terminal are multiplexed and transmitted to the low-priority terminal by multicast transmission. In the case of sound, since it operates so as not to reproduce the audio data from the low priority terminal among the audio data received from the server, even if the audio data multicast-transmitted from the server is encoded at a low bit rate, It is possible to obtain a telephone conference system that does not sense echo.

  In the sixth embodiment, the example in which the voice data from the high priority terminal is arranged in the first half of the multiplexed data and the voice data from the low priority terminal is arranged in the second half is explained. However, the arrangement method is limited to this. Is not to be done. An arrangement rule is determined in advance so that a low-priority terminal that receives multiplexed data can separate voice data from a high-priority terminal and voice data from a low-priority terminal from the multiplexed data. Accordingly, the audio data may be multiplexed. For example, the rule may be such that the voice data of the high priority terminal and the voice data of the low priority terminal are alternately arranged every 1 bit, or alternately every 8 bits.

Embodiment 7 FIG.
FIG. 13 is a block diagram showing a configuration of a call conference system according to the seventh embodiment.
In FIG. 13, the operations of the voice packet receiving unit 101, the voice synthesizing unit 143, the voice encoder 106, and the multicast voice packet transmitting unit 108 of the server 100 are the same as those in the first embodiment described with reference to FIG. The operations of the voice packet receiving unit 102, the voice decoder 109, the control packet receiving unit 131, the message reception control unit 132, and the control packet transmission unit 133 are the same as those in the third embodiment described with reference to FIG. The operation of the speech synthesizer 143 is the same as that of the fourth embodiment described with reference to FIG. 7, and the operation of the speech code multiplexer 161 is the same as that of the sixth embodiment described with reference to FIG.

  The operations of the high priority terminals 200a and 200b are the same as those in the first embodiment described with reference to FIG.

  In server 100, speech code multiplexing section 161 multiplexes the output of speech encoder 106 and the output of speech packet receiving section 102 and outputs the result to multicast speech packet transmitting section 108, but the output from speech packet receiving section 102. If there is no signal, the output of the speech encoder 106 is output to the multicast speech packet transmitter 108 as it is.

Next, the operation of the low priority terminals 300a to 300c of the seventh embodiment will be described with reference to FIG. FIG. 14 is a block diagram showing an internal configuration of the low priority terminal 300a according to the seventh embodiment.
14, the operations of the microphone 301, the A / D converter 302, the voice encoder 304, the voice packet transmission unit 305, the voice decoder 308, the D / A converter 310, and the speaker 311 are the same as those described in FIG. This is the same as the first embodiment. The operations of the talk switch 331, the control packet transmitter 332, the control packet receiver 333, and the speech permission lamp 334 are the same as those in the third embodiment described with reference to FIG. The operations of the switch 309 and the multicast voice packet receiving unit 306 are the same as those in the fourth embodiment described with reference to FIG.
The internal configuration of the low priority terminals 300b and 300c is the same as that shown in FIG.

The operations of the speech code separation unit 361, speech decoder 342, and speech synthesis unit 343 are also basically the same as described with reference to FIG. The multicast voice packet receiving unit 306 that has received the multicast voice packet including the multiplexed data of the voice data of the high priority terminals 200a and 200b and the voice data of the low priority terminals 300a to 300c extracts the payload part, that is, the multiplexed data. The audio code separation unit 361 outputs the low bit rate code of the first half of the multiplexed data to the audio decoder 308 and outputs the low bit rate code of the second half to the audio decoder 342.
However, as described above, there are cases where the audio data of two types of low bit rate codes are not multiplexed. In this case, the audio code separation unit 361 inputs the input from the multicast audio packet reception unit 306 to the audio decoder 308. Are not output to the speech decoder 342. The speech decoder 342 decodes the speech data of the low bit rate code to the PCM code when the speech data of the speech code separation unit 361 is input, and outputs the PCM code to the switch 309. If there is no input, the speech decoder 342 generates the silent PCM code. Output to the switch 309.

When the server 100, the high-priority terminals 200a and 200b, and the low-priority terminals 300a to 300c operate as described above, while the user of the low-priority terminals 300a to 300c who is allowed to speak is speaking, the control packet receiving unit 333 switches to the switch 309. Is 1 and the switch 309 outputs a silent PCM code to the speech synthesizer 343. Therefore, the voice data of the low priority terminals 300a to 300c multiplexed in the second half of the multicast voice packet is not reproduced, and the occurrence of echo can be prevented.
Further, since any one of the low-priority terminals 300a to 300c permitted to speak is used, the user of the low-priority terminal permitted to speak does not miss the voice of the other low-priority terminals.

  In addition, since the multiplexed data in which the voice data of two types of low bit rate codes is multiplexed is multicast-transmitted from the server 100 to the low-priority terminals 300a to 300c, the network load increases, but the reverse direction Since the voice packets are not simultaneously transmitted from the plurality of low priority terminals 300a to 300c to the server 100 from the low priority terminals 300a to 300c, the network load is reduced.

  As described above, according to the seventh embodiment, three or more terminals are divided into a high priority terminal and a low priority terminal, and the server receives voice data from other terminals other than the terminal for the high priority terminal. The low-priority terminal that is allowed to speak is sent to the server by multiplexing and transmitting the voice data from the high-priority terminal and the voice data from the low-priority terminal to the low-priority terminal. While transmitting the audio data, it operates so as not to reproduce the audio data from the low priority terminal among the audio data received from the server. Therefore, the audio data multicast-transmitted from the server is encoded with the low bit rate. It is possible to obtain a telephone conference system that does not sense echo even when the terminal is present.

  In the first, second, fourth, and sixth embodiments, the voice detection unit 303 of the low-priority terminals 300a to 300c determines whether the transmission voice is voice and outputs the determination result to the switch 309. However, it is assumed that a talk switch is provided instead of the voice detection unit 303 and the user presses the talk switch while speaking, and information on whether the talk switch is pressed / not pressed is used instead of the voice / silence determination result. Even if it is the structure which outputs to, the same effect can be acquired.

  In the first to third embodiments, the voice selection unit 105 is configured to select voice data to be multicast transmitted from the input voice data of the PCM code. It is also possible to adopt a configuration in which rate code audio data is input and selected.

  In the first to seventh embodiments, low bit rate code audio data is transmitted and received between the server 100 and the low priority terminals 300a to 300c. However, instead of the low bit rate code, a PCM code is used. However, it is possible to obtain a telephone conference system that does not sense echo in the low priority terminals 300a to 300c.

  Further, in the first to seventh embodiments, it has been described that the priority (high priority terminal or low priority terminal) for each terminal is determined in advance based on the IP address or the like. The priority may be changed when the moderator changes. In that case, the terminal may have both the function for the low priority terminal shown in FIG. 2 and the high priority terminal function shown in FIG.

  In addition to the above, within the scope of the present invention, the present invention can be freely combined with each embodiment, modified any component of each embodiment, or omitted any component in each embodiment. Is possible.

100 server, 101, 102, 204 voice packet receiver, 103, 143, 343 voice synthesizer, 104, 203, 305 voice packet transmitter, 105 voice selector, 106, 141, 304 voice encoder, 107 selection information addition , 108, 142 Multicast voice packet transmitter, 109, 109a to 109c, 308, 342 Voice decoder, 121 Receiving side voice synthesizer, 131, 333 Control packet receiver, 132 Speech acceptance controller, 133, 332 Control packet Transmitter, 161 Voice code multiplexer, 200a, 200b High priority terminal, 201, 301 Microphone, 202, 302 A / D converter, 205, 310 D / A converter, 206, 311 Speaker, 300a-300c Low priority terminal 303 Sound detection unit, 306, 341 Multi Cast voice packet reception unit, 307 selection information separation unit, 309 switch, 331 talk switch, 334 speech permission lamp, 361 voice code separation unit.

Claims (8)

In a call conference system consisting of a server and three or more terminals,
The three or more terminals are divided into high priority terminals and low priority terminals,
The server synthesizes and transmits a voice signal transmitted to the server from a terminal other than the high priority terminal for each of the high priority terminals, and the high priority terminal for the low priority terminals. Among the audio data transmitted from the low-priority terminal and the audio data transmitted from the low-priority terminal to the high-priority terminal with priority, and the selected audio signal is selected as the high-priority signal. Transmit in a multicast manner together with selection information indicating whether the voice signal from the terminal or the low priority terminal is selected,
When the low-priority terminal receives and reproduces the audio data transmitted from the server by the multicast method, the low-priority terminal is based on the selection information while transmitting valid audio data of the terminal to the server. A call conference system, wherein the received audio data is reproduced if it is audio data from the high priority terminal. In a call conference system consisting of a server and three or more terminals,
The three or more terminals are divided into high priority terminals and low priority terminals,
The server synthesizes and transmits a voice signal transmitted to the server from a terminal other than the high priority terminal for each of the high priority terminals, and the high priority terminal for the low priority terminals. The voice data transmitted from the server to the server and the voice data transmitted from the low priority terminal to the server are multiplexed and transmitted in a multicast manner,
When the low-priority terminal receives and reproduces the audio data transmitted from the server by the multicast method, the low-priority terminal receives the audio data received while transmitting valid audio data of the terminal to the server. A call conferencing system for reproducing voice data from the high priority terminal. In a call conference system consisting of a server and three or more terminals,
The three or more terminals are divided into high priority terminals and low priority terminals,
The server synthesizes and transmits a voice signal transmitted to the server from a terminal other than the high priority terminal for each of the high priority terminals, and the high priority terminal for the low priority terminals. The voice data transmitted from the low-priority terminal to the server and the voice data transmitted from the low-priority terminal to the server separately by a multicast method,
When the low-priority terminal receives and reproduces the audio data transmitted from the server by the multicast method, the low-priority terminal receives the audio data received while transmitting valid audio data of the terminal to the server. Is a voice conferencing system that reproduces audio data from the high-priority terminal.   The low-priority terminal detects the presence or absence of voice data of its own terminal, and determines that the voice data in which the voice is detected is transmitted to the server as the valid voice data. The telephone conference system according to any one of claims 1 to 3. The server allows or disallows the speech of the user of the low priority terminal;
The said low priority terminal transmits the said user's speech to the said server as the said effective audio | voice data, when the permission of the user of the own terminal is received from the said server. The call conference system according to claim 1. The voice data transmitted / received between the server and the low priority terminal is encoded with a low bit rate at a bit rate lower than that of PCM. Call conference system described in the section.   The server is a combination of voice data transmitted from the plurality of low-priority terminals to the server as voice data from the low-priority terminals to be included in voice data transmitted by multicast to the low-priority terminals. The call conference system according to claim 4, wherein:   The server uses voice data transmitted to the server from the low-priority terminal permitted to speak as voice data from the low-priority terminal to be included in voice data transmitted by multicast to the low-priority terminal. The call conference system according to claim 5.

Images