JPH06296202A - Communication method applied between multi-media communications equipment - Google Patents

Abstract

PURPOSE:To enable an operator to optionally select a voice CODEC for communication by providing a constitution where one of both communication equipments always sends a command first to the other equipment and the equipment receiving the com mand sends back a command of the same contents as the received one. CONSTITUTION:A communication equipment of the calling side knows the communicating ability of a communication equipment of the called side by exchange of the ability information and then confirms that the communication equipment of the called side is capable to use the voice CODEC 3 selected by a operator. Then a mode switching command is sent to the calling side to point a communication mode for application of the CODEC 3. The communication equipment of the called side receives the mode switching command after exchange of the ability information and sends a command of the same contents as the received one back to the communication equipment of the calling side. One of units included in the CODEC 3 is selected based on the received command and a prescribed mode is set. At the calling side, a mode is set based on the received command. As a result, the same communication mode is set between both communication equipments of the calling and called side respectively. It is capable to call between both of operators.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of types of voice CODECs (coders) each of which is used for two devices communicating with each other.
The invention relates to a communication method of a multimedia communication device including an and decoder.

[0002]

2. Description of the Related Art CCITT recommends various specifications for multimedia communication devices such as videophones and videoconference devices.

When such communication devices communicate with each other, after the call connection, the capability information is exchanged with each other to determine the capability common to the own device and the partner device. Then, each device sends a mode switching command to the partner device in order to communicate with the determined common capability. Each device sets a communication mode according to the received mode switching command and communicates with each other.

One of the above communication modes is voice CODEC.
There are specifications. In CCITT, as a specification of this audio CODEC, Recommendation G. 711, G.I. 722 and G.H. 7
28 types are defined. Recommendation G. 711 is 3.
Normal voice CODE that transmits a 4 kHz voice band signal
C is defined. Recommendation G. 722 has a voice band of 7 kHz
z, which has high sound quality, and is recommended by G. 728 is 3.
It defines a high-performance one that compresses a voice band signal of 4 kHz to a data transmission rate of 16 kbps and transmits it.

When both communicating devices are equipped with a plurality of types of voice CODEC, the CCITT recommendation recommends selecting the communication function with the highest function.

According to this recommended condition, the communication device equipped with the above-mentioned three types of audio CODECs is always recommended by G.264. 72
8 voice CODECs will be selected. Then, for example, even if the operator wants to make a call with high sound quality, the recommendation G. The 722 voice CODEC cannot be used.

Therefore, during communication, the operator makes a voice COD.
It is conceivable to arbitrarily select EC. Now, assuming that the two communication devices communicating with each other are A and B, when the operator arbitrarily selects the communication device as described above, the communication device A recommends G. 722 audio CODEC is selected, and communication device B selects recommendation G.722. It happens that the selection states are different between the two devices, such that 728 voice CODECs are selected.

The CCITT recommendation allows asymmetric communication in which a communication mode in which signals are transmitted from one to the other and a communication mode in which signals are transmitted from the other to one, on the contrary, are different. Therefore, in the above case, for the communication devices A to B,
Recommendation G. 722, a mode switching command corresponding to ITU. A mode switch command corresponding to 728 is sent.

When the communication devices A and B support such a state, for example, in the communication device A, the transmission signal is transmitted according to Recommendation G.264.
722 audio CODEC and processes the received signal according to Recommendation G.722.
Must be processed with 728 voice CODEC.

By the way, usually, the above three types of audio CODE
Each C is composed of individual hardware units. A circuit for synthesizing and processing the transmission signal and the reception signal, such as an echo canceller and a side tone circuit, is arranged in each unit. Therefore, as described above, when the transmitting side and the receiving side of two different units are separately used, the audio signal cannot be correctly transmitted and communication becomes impossible.

[0011]

As described above, conventionally, both devices communicating with each other have a plurality of voice CODECs.
In the case of the above, there is a problem in that it is not possible to arbitrarily select the voice CODEC for communication.

The present invention solves the above problems and provides a voice CO
An object of the present invention is to provide a communication method of a multimedia communication device capable of arbitrarily selecting DEC for communication.

[0013]

To this end, in the first invention of the present application, one of the two devices communicating with each other, which is predetermined, always sends the mode switching command first, and the other one sends the mode switching command. After receiving, the mode switching command having the same contents is sent to one side.

In the second aspect of the invention, each device waits for a mode switching command from the other party for a different waiting time set by a random number each time, and when the mode switching command is received within that time, the mode of the same content is received. When the switching command is sent to the other party and the mode switching command is not received within the above time, the mode switching command is sent from the device itself, and the contents of the mode switching command and the mode switching command sent thereafter are also received. If they are different, the communication procedure is re-executed from the exchange of capability information.

In the third invention, one device indicates a specific voice CODEC in the capability information to be transmitted to the other,
The other sends a mode switching command indicating the instructed voice CODEC to one.

[0016]

According to each of the above inventions, when one device sends a mode switching command instructing a specific voice CODEC, the other device also sends back a mode switching command having the same content, so that both devices communicate with each other. Can be set to mode. In this case, in one of the devices, the operator sets a desired voice CODEC
The DEC can be arbitrarily selected to communicate.

[0017]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a multimedia communication device according to an embodiment of the present invention.
In the figure, the microphone 1 is for inputting a call voice,
The speaker 2 outputs the received voice. Voice C
The ODEC 3 is for converting a call voice signal into a digital signal and vice versa. In this embodiment, CCITT recommendation G.264 is included in the audio CODEC 3. 711, G.I. 722 and G.H. 3 according to 728
Equipped with different types of units.

The television camera 4 is for picking up a human image of the operator to be transmitted. The TV monitor 5
The received image is displayed. The image CODEC6 is
Recommendation H. The specification conforms to H.261 and converts the video signal of the television camera 4 into a digital signal and vice versa.

The document processing device 7 is for creating and displaying a character document or the like. The code data input / output unit 8 inputs / outputs character information as code data. The multiplexer / demultiplexer 9 uses the recommended H.264 standard. According to the specifications compliant with 221, the audio, video and code data to be transmitted are multiplexed, or the received data is separated as respective information. The ISDN communication unit 10 is connected to the ISDN and communicates with other devices via the ISDN.

Next, a first embodiment of the communication operation of the multimedia communication device having the above configuration will be described.

In the present embodiment, when communicating, the operator selects a desired voice CODEC to be used in a predetermined operation, sets the other party, and activates the communication operation. The activated communication device makes a call and connects with the other party.

The two devices connected to the call exchange capability information with each other, as shown in FIG. This capability information is 64
BAS arranged in a channel frame of kbps
(Bitrate Allocation Signal
l). This exchange of capability information is based on the CCI
Execute in two steps according to TT's recommendation.

FIG. 3 shows an example of a part of the capability information exchanged here. In the figure, “μ-rule” is the recommendation G.
711 shows the communication capability by audio CODEC.
"G.725-T2" is a recommendation G.725. 722 shows the same capability. “Au-16 kb / s” is recommended in G. 728
Of the same ability. "2x64" is the ISDN B
The communication capability of using two channels is shown.
“QCIF” indicates one of the video signal formats. "1 / 29.97" and "2 / 29.97"
Indicates the time of the minimum coding interval of the video signal. In addition to this information, various information is exchanged.

The communication device on the calling side, as shown in FIG.
The communication capability of the called device is known by exchanging capability information (process 101). It then verifies that the called device is capable of using the voice CODEC selected by the operator. Then, the mode switching command for instructing the communication mode using the voice CODEC is sent to the called side (process 102). This mode switching command is also BA
It is transmitted by S.

In this mode switching command, for example, information "G.722, m2, 1 × 64" is transmitted. In this case, “G.722” is the recommendation number “m
2 ”is a data transmission rate of 56 kbps,“ 1 × 64 ”
Respectively indicate the use of one of the B channels.

As shown in FIG. 5, the communication device on the called side is
After exchanging the capability information (process 201), the process waits until a mode switching command is received (N loop of process 202).
When the mode switching command is received (process 202)
Y), the mode switching command having the same content is sent back to the calling side (process 203).

Then, according to the received mode switching command, one unit in the audio CODEC 3 is selected and a predetermined mode setting is executed (process 204).

The calling side receives the mode switching command transmitted from the called side (Y in process 103) and sets the mode in the same manner (process 104).

As a result, each device on the calling side and the called side is
The same communication mode is set. In the present example, G. 722
The communication mode using the voice CODEC is set, and a call between the two operators becomes possible (process 105).

After this, the operator activates the videophone or communication operation of document transmission as required. When these starting operations are executed, the communication device establishes a predetermined communication connection with the partner device by a known procedure and executes each communication.

As described above, in the present embodiment, the calling side device first transmits the mode switching command, and the called side device receives the mode switching command and then issues the mode switching command of the same content. It is sent to the caller.

Therefore, the operator on the calling side receives the voice COD.
If you select EC, both devices will output the audio CODEC.
Is set to the communication mode that uses
It becomes possible to arbitrarily select C for communication.

In the above embodiment, the mode switching command may be sent by the calling side first or by the called side first. Further, it is not necessary to distinguish between the calling side and the called side, and for example, when there is a master-slave relationship between the two devices, either one of them may be determined.

Next, a second embodiment of the communication operation of the communication device shown in FIG. 1 will be described.

In the communication device of this embodiment, a desired voice CODEC is set in advance by the operator. Then, in the same manner as in the above-described embodiment, the operator's activation operation calls the other party to start the communication operation.

In the present embodiment, after the communication is started, the calling side and the called side execute the same processing as shown in FIG. That is, each device first exchanges capability information (process 30).
1). Next, the waiting time is determined by a random number. For example,
R is a random number generated in the range of 0 to 3 and the time required to send 15 bytes of capability information once by BAS is 300 (m
s), the waiting time T (ms) is calculated as T = 300 + 200 × R (process 302).

Next, during the waiting time T, the reception of the mode switching command from the other party is monitored (process 30).
3, process 304 from N of process 303, and process 303 from N of process 304).

When the mode switching command is received within the above period (Y in step 304), the mode switching command having the same content is sent to the other party (step 305).

Then, the mode is set according to the received mode switching command (process 306). As a result, the calling side device and the called side device are set to the same communication mode, and a call between the two operators becomes possible (process 307).

On the other hand, when the mode switching command is not received within the above period (Y in step 303), the mode switching command is sent to the other party according to the voice CODEC preset in the own device (( Process 308).

In the present embodiment, as described in the above processing 304, 305, when the mode switching command is sent, the other party returns the mode switching command having the same content.

When the mode switching command returned from the other party is received (process 309), the contents are checked (process 310), and if they match (Y in process 310), the mode is set and communication is performed as described above. Yes (to step 306).

Now, as shown in FIG. 7, if the calling side and the called side happen to calculate the same time T1 as the waiting time T, both sides simultaneously send a mode switching command. To do.

In this case, the communication modes designated by the transmitted mode switching commands may be different from each other. In this way, when the contents of the mode switching commands do not match (N in process 310), the communication operation is re-executed from the capability information exchange procedure (process 301). Such re-execution of the communication operation is stipulated in the CCITT recommendation as "mode 0 forced setting procedure".

The calling side and the called side re-execute the communication operation in this way, and the waiting time T is newly calculated again. Here, as shown in FIG.
2. If the called side calculates a waiting time T3 longer than that, the mode switching command is sent from the calling side after the waiting time T2 has elapsed. Then, the called side returns a mode switching command having the same content, and communication between the two becomes possible.

As described above, in this embodiment, each device is
It waits for a mode switching command from the other party for a different waiting time each time, and when the mode switching command is received within the waiting time, the mode switching command having the same content is returned. If the mode switch command is not received within the waiting time, the mode switch command is transmitted from the device itself, and if the content of the mode switch command received from the other party after that is different, communication of the capability information is exchanged to the communication operation. I'm trying to re-execute.

As a result, if the operator sets a desired voice CODEC in each device in advance, the communication is executed according to the setting, so that the voice CODEC can be arbitrarily selected and communicated.

In the above embodiment, the case where communication is performed between devices having the same function has been described, but correct communication can be performed between the device of the above embodiment and a conventional device. In this case, the conventional device first sends the mode switching command, and the device of the above embodiment receives the mode switching command and returns the mode switching command having the same contents.

Next, a third embodiment of the communication operation of the communication device shown in FIG. 1 will be described.

In the present embodiment, the calling operator sets a desired voice CODEC in the apparatus.

When the communication device on the calling side makes a call to the other party and starts communication, as shown in FIG. 8, first, the capability information is exchanged with the other party. In this embodiment, at this time, the information indicating the voice CODEC set by the operator is described at the head of the information list of the capability information to be transmitted to the other party. For example, G.I. Assuming that the audio CODEC of G.722 has been set, as shown in FIG. 722 voice CODEC
The capability information of “G.725-T2” indicating that is described at the top of the information list. Such capability information is transmitted to the other party, and the capability information from the other party is received (process 40).
1).

FIG. 10 shows an example of the communication procedure of this embodiment.

The calling side device then sends the voice code
A mode switching command according to the setting of C is transmitted (process 402).

As shown in FIG. 11, when the called communication device exchanges the capability information (process 501), it sends a mode switching command corresponding to the voice CODEC listed at the head of the received capability information list. Yes (process 502).
Then, it receives a mode switching command from the calling side (process 503) and sets the mode (process 504).

The calling side also receives the mode switching command from the called side (step 403) and sets the mode (step 4).
04).

As a result, the calling side and the called side are set to the same communication mode, and the call between both operators becomes possible (process 405, process 505).

As described above, in this embodiment, the calling side is
The desired voice CODEC information is set at the head of the information list of the capability information and sent to the called side, and the called side sends a mode switching command according to the voice CODEC indicated at the head of the information list. I have to.

As a result, when the calling operator sets the desired voice CODEC, each device is correctly set to the communication mode according to the setting, and predetermined communication becomes possible.

In the above embodiment, the calling side notifies the called side of the desired voice CODEC by describing the information of the desired voice CODEC at the head of the list of capability information. For example, by transmitting and notifying identification information indicating the order of the desired voice CODEC,
It is also possible to notify by other methods.

Although the desired voice CODEC is notified from the calling side to the called side, it may be notified from the called side to the calling side.

Further, in each of the above-mentioned embodiments, the communication device executes the specific communication operation in each of the embodiments, but for example, the communication device of the first or third embodiment performs the communication. After the start, if it is determined that the other party is the conventional device, the communication operation of the second embodiment may be executed. In this case, whether the destination device is a conventional device is MBE (Mul) which is one of the capability information.
It can be determined by the ability of the ti-Byte Extension).

Further, in the above embodiment, as a case where the communication modes should not be different between the two communicating devices,
Although the audio CODEC settings have been described as an example, even in other settings in which the communication mode settings should not be different,
The present invention can be applied.

[0064]

As described above, in the first invention of the present application, one device always sends the mode switching command first, and the other device sends back the mode switching command having the same contents as the received mode switching command. Therefore, the operator can arbitrarily select the voice CODEC to communicate.

In the second invention, each device waits for a mode switching command from the other party for a different waiting time each time.
When the mode switching command is received, the mode switching command having the same contents is returned, while when the mode switching command is not received, the mode switching command is sent from the device itself, and the mode switching command and the sending instruction received thereafter. If the contents are different from the mode switching command
Since the communication procedure is re-executed after the exchange of the capability information, the voice CODEC can be arbitrarily selected and communicated as in the above.

In the third aspect of the invention, one device instructs the desired voice CODEC in the capability information to be transmitted, and the other device sends the mode switching command in accordance with the instruction, so the same as above. In addition, it becomes possible to arbitrarily select and communicate with the voice CODEC.

[Brief description of drawings]

FIG. 1 is a block diagram of a multimedia communication device according to an exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a communication procedure in the first example of the communication operation.

FIG. 3 is an explanatory diagram showing an example of capability information exchanged between devices.

FIG. 4 is an operation flowchart of a calling side device.

FIG. 5 is an operation flowchart of a called-side device.

FIG. 6 is an operation flowchart of each device in the second embodiment of communication operation.

FIG. 7 is an explanatory diagram showing an example of a communication procedure in the embodiment.

FIG. 8 is an operation flowchart of a calling side device in a third embodiment of communication operation.

FIG. 9 is an explanatory diagram showing an example of capability information transmitted from a calling side in the embodiment.

FIG. 10 is an explanatory diagram showing an example of a communication procedure in the above embodiment.

FIG. 11 is an operation flowchart of the called side device in the above embodiment.

[Explanation of symbols]

 1 Microphone 2 Speaker 3 Audio CODEC 4 Television camera 5 Television monitor 6 Image CODEC 7 Document processing device 8 Code data input / output unit 9 Multiplexing / separating unit 10 ISDN communication unit

Claims (4)

[Claims] 1. A mode switching command indicating one voice CODEC to be used after communicating between two devices and exchanging capability information indicating the type of voice CODEC included in the device with each other. In the communication method of a multimedia communication device for transmitting and communicating to a device, one of the two devices, which has been determined in advance, first sends a mode switching command to the other, and the other has the same contents as the received mode switching command. A communication method of a multimedia communication device, wherein a mode switching command is sent to one side. 2. A mode switching command indicating one voice CODEC to be used after communicating between two devices and exchanging capability information indicating the type of voice CODEC included in the own device with the destination. In the communication method of the multimedia communication device for transmitting and communicating to
After exchanging capability information, wait for a mode switching command from the other party for a different waiting time each time based on random numbers, and if a mode switching command is received within that time, the same content as the received mode switching command If the mode switching command is sent to the other party while the mode switching command is not received within the above time, the device sends the mode switching command to the other party and the mode switching command received thereafter and the mode sent. A communication method of a multimedia communication device, wherein when the contents of the switching command are different, the communication procedure is re-executed after the exchange of the capability information. 3. A mode switching command indicating one voice CODEC to be used after communicating between two devices and exchanging capability information indicating the type of voice CODEC included in the device with each other. In the communication method of a multimedia communication device for transmitting to and communicating with a device, one of the above two devices indicates a specific voice CODEC in the capability information to be transmitted to the other, and the other of the two devices transmits the instructed voice CODE.
A communication method of a multimedia communication device, wherein a mode switching command indicating C is sent to one side. 4. The communication method of the multimedia communication device according to claim 3, wherein the specific voice CODEC is designated by a position on the list of the capability information.