JPH04160853A - Multi-medium communication method - Google Patents

Abstract

PURPOSE:To communicate a voice signal of a television telephone call and a telephone call signal simultaneously by using other voice CODEC than a mu-law for a television telephone set. CONSTITUTION:The system for the method is provided with a handset 1, a microphone 2, a speaker 3, a voice interface section 4, a voice coding decoding section 5, a camera 6, a document camera 7, a display section 8, a data interface section 12, an operation section 13, a system control section 14, a multiplexer/ demultiplexer section 17, and a line interface section 18. Then other voice CODEC than a mu-law is used for a voice CODEC of a television telephone set when the television telephone set and the telephone set are operated simultaneously. Thus, the mu-law is used for the voice CODEC of the television telephone set and the voice signal of a television telephone call and a telephone call signal are sent simultaneously.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is connected to an 15DN network and complies with CCITT Recommendation T, 3.
The present invention relates to a multimedia communication device defined in 20.

(Prior Art) In recent years, communication services using 15DN lines have been put into practical use, and AV (Audio Visual) services such as video telephones and video conference systems using such digital lines are attracting attention. The service specifications, protocol specifications, and multimedia multiplexing frame structure specifications of CCITT Recommendation or Draft Recommendation H.320.
242, H, 221, etc. H, 22
1, frame structure and terminal capability exchange in AV services on 64 kbps to 1920 kbps channels 8 RAS (Bit-ra 1 allocation signal, Bit-ra 4e A11oca) used for specifying communication mode, etc.
tion Signal) is defined. 8.242 defines protocols such as capability exchange and communication mode switching between AV terminals using RAS, and H.320 defines system aspects of AV services in general.

In the above recommendations or draft recommendations, after setting up an end-to-end physical connection and establishing in-channel synchronization, the terminal capability exchange sequence using RAS in-channel, the mode switching sequence by specifying the communication mode, etc. The procedures define methods for communicating multimedia such as images, audio, and data between terminals.

However, how each terminal changes its own terminal capabilities depending on the situation and which communication mode to use within the range of exchanged capabilities is outside the scope of the regulations.

The information transfer rate of each media in multimedia communication is determined by specifying the audio encoding method for audio information, and by specifying whether or not to use it and the transfer rate if used. The image information transfer rate is the remainder obtained by subtracting the audio information transfer rate and the data information transfer rate from the information transfer rate of the entire communication channel.

Therefore, the information regarding the transfer rate specified when notifying the other party of one's own communication mode using RAS is the audio encoding method and data transfer rate, and for images, the transfer rate is automatically set within the system. .

(Problems to be Solved by the Invention) According to Recommendation H.320, it is stated that AV terminals are interconnected with telephones connected to the PSTN and telephones connected to ISDN, but it does not discuss the simultaneous operation of AV calls and telephone calls. Not specified.

The present invention has been made in view of the above circumstances, and its purpose is to provide a multimedia communication method for realizing simultaneous videophone and telephone operations in a multimedia communication device connected to an l5DN basic interface. It is about providing.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a multimedia communication method for multiplexing and mutually communicating multimedia information such as audio information, video information, and data. This allows a videophone audio codec other than μmlaw to be used during simultaneous operation.

Further, as another invention, in a multimedia communication method in which multimedia information such as audio information, video information, data, etc. is multiplexed and mutually communicated, when reducing the transfer rate mode,
Priorities for assigning transfer modes for data, images, and audio are determined in advance, and transfer modes are set according to the priorities when assigning transfer rates.

Furthermore, as another invention, in a multimedia communication method in which multimedia information such as audio information, video information, data, etc. is multiplexed and mutually communicated, when a call is received during communication in transfer rate mode 2B by videophone. , the videophone transfer rate was reduced to 1B, and incoming calls were accepted on the vacant B channel.

(Operation) In the multimedia communication method according to the present invention, when the videophone and telephone are operated simultaneously, a codec other than μmlaw is used as the audio codec for the videophone. As a result, μmlaw can be used as a telephone voice codec, and videophone voice and telephone communication can be communicated simultaneously.

Furthermore, in a multimedia communication method according to another invention, when reducing the transfer rate mode, the priority order of transfer mode assignment for data, images, and audio is determined, and the transfer mode is set according to the priority order when transferring the transfer rate.

Thereby, it is possible to minimize the deterioration of communication functions due to reduction in transfer rate mode.

Additionally, if a call arrives during a video call in transfer rate mode 2B, the video call transfer rate will be set to 1.
B and accepts incoming calls on the vacant B channel. This allows simultaneous operation of the telephone and television.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a multimedia communication device to which the method of the present invention is applied.

In the figure, 1 is a handset which is one of the audio input/output means of this device, 2 is a microphone which is one of the audio input devices of this device, 3 is a speaker which is one of the audio output means of this device, 4 is a handset 1 . Switching process for switching between microphone 2 and speaker 3; on/off hook detection process for detecting whether handset 1 is on-hook or off-hook; eliminating echo when microphone 2 and speaker 3 are used as audio input/output means 5 is an audio interface unit that performs echo cancellation processing and generation processing of dial tones, ring tones, busy tones, ring tones, etc. for the purpose of 64 kbps PCMA-law, 64 kbps PC according to instructions from the system control unit 14;
M μmlaw, 64bPs156kbPs/48kb
Ps SB-ADPCM, 32kbps ADPC
M, 32kbps ADPCM, 16kbps (
For example, it is an audio encoding/decoding unit that encodes a transmitted audio signal and decodes a received audio signal according to an audio signal encoding/decoding algorithm such as APC-AB) or 8 kbps.

6 is one of the image input means of this device, and is a camera for inputting self-portraits, etc. 7 is one of the image input means of this device, and is a document camera for inputting pictures, drawings, etc.; 8 is a camera 6 or a display section for displaying input images from the document camera 7, images received from the other party, operation drawings, etc.; 9 for displaying image input means switching processing, input images, received images, and operation screens according to instructions from the system control section 14; A video interface unit 10 performs display switching processing and image signal synthesis processing for displaying them separately on the display unit 8, and a video interface unit 10 performs encoding of transmitted images and decoding of received image signals in accordance with CCITT Recommendation Draft H, 261. This is a video encoding/decoding unit that performs video encoding/decoding.

11 is a data terminal for performing data communication; 12 is a terminal that notifies a demultiplexing unit 17 (to be described later) of transmission data from the data terminal 11 and the system control unit 14, and transmits received data to the data terminal 11 or the system control unit 14; This is a data interface unit that sends notifications.

13 is an operation unit such as a keyboard or touch panel used to input control information for controlling the device in general; 14 is a C
The system control unit is equipped with a PU, ROM, RAM, auxiliary storage device, etc., and monitors the status of each part and controls the entire device, operates according to the status, creates display screens, executes application programs, etc., and performs call control. D channel control section 15 that performs in-channel control, and in-channel control section 16 that performs in-channel control.
including.

Reference numeral 17 indicates a frame for transmitting an audio signal from the audio encoding/decoding section 5, an image signal from the video encoding/decoding section 10, data from the data interface section 12, and RAS from the system control section 14 in accordance with CCITT Recommendation H, 221. A demultiplexer 18 multiplexes the received frame into units of media, separates the received frame into constituent media, and notifies each unit. Reference numeral 18 is a line interface unit that controls the line according to the I5DN user/network interface.

FIG. 2 is a block diagram showing the configuration of the audio encoding/decoding section 5 in detail. 5-1 converts the telephone port P1 and videophone voice port P2 from the demultiplexer 17 into PCM.
P-law codec (64Kbit/5) 5-
2. PCM A-law codec (64Kb i
t/5) 5-3, APC-AB (16Kb it
/s) Codec 5-4, SB-ADPCM (64,
This is a switching unit for connecting to various audio codecs of the codec 5-5 (56, 48 Kbit/s).

FIG. 3 shows an example of a procedure for negotiating with a partner terminal the proportions of image, voice, and data communication, respectively, using RAS commands. Here, an example is given in which terminal A lowers its communication capability to 1B while communicating using two B channels.

Between terminal A and terminal B, the transfer rate is 2B, LSD (
Low 5peed Data) 4.8 to b i
t/s, audio 48Kbit/s (SB-
ADPCM), with video (the rest of 2B is used for video transfer) is used for communication (arrow AR1)
. In order to delete 1B, terminal A sends the mode switching BAS command a, transfer rate 1B, LSD 4.8Kb i
t/s, audio APC-AB (16Kbft/s),
Set ``Video exists'' (remaining 1B is used for video transfer) and send to terminal B. As a result, transmission from terminal A to terminal B becomes a communication rate of 1B.

Next, in order to set the transmission rate from terminal B to terminal A to 1B, terminal A transmits to terminal B a capability exchange RAS command b that sets the transfer rate to 1B. Terminal B, which received this command, switches the bus mode to 1B, which is the maximum common denominator between terminal A's transfer capacity 1B and its own terminal's transfer capacity 2B, using bus command C.
and send it to terminal A.

By exchanging commands as described above, the transfer rate between terminal A and terminal B becomes 1B for both transmission and reception.

Next, the operation of terminal A will be explained. AV terminal A and AV terminal B have transfer rate mode 2B and data mode 4.8Kbi.
Assume that communication is being performed with the settings (terminal A): t/s, audio transmission mode: 48 Kbit/s, video transmission mode: with video (the remainder of 2B is used for video transmission). When terminal A receives a call from a telephone connected to the PSTN network, terminal A communicates with terminal B using transfer rate mode 1B, data mode 4.8 Kbit/s, audio transmission mode 48 Kbit/s, and video transmission. Mode: Set to transmission mode without video, and reduce the transfer rate capability of the own terminal to 1.
B, communication with terminal B is limited to 1B, and released 1
B accepts incoming telephone calls connected to the PSTN network.

FIG. 4 is a flowchart for explaining the operation of the D channel control section 15 when a telephone call is received.

First, a SET UP message is received and it is determined that the message is a telephone call (step Sl).

If telephone communication is in progress in step S2, the incoming call is rejected with "received user busy" in step S6. If telephone communication is not in progress, the user is notified of the incoming telephone call by ringtone or display (step 33).

If the user does not accept the incoming call in step S4, the incoming call is rejected in step S6. If the user accepts the incoming call, the in-channel control unit 16 is notified of the incoming call (step 55).

FIG. 5 shows the operation of the in-channel control section 16 when receiving a telephone call notification from the D-channel control section 15.

First, in step 510, a notification of an incoming telephone call is received from the D channel control section 15.

In step 311, it is determined whether the videophone call is in progress. If communication is not in progress, switching unit 5-1 is switched in step S20.
Use the telephone boat PI as a voice codec μmlaw5-2
At step S21, the voice interface section 4 is switched to a handset, and at step 322, an incoming telephone call is accepted.

If the videophone call is in progress in step 311, step S
Proceed to step 12. In step 312, the switching unit 5-1 is controlled, and the telephone boat P1 is set to the μ-law codec 5-2, and the videophone boat P2 is set to the A-law codec 5-2.
-3 respectively. In step 513, the voice of the telephone is transmitted to the handset 1, and the voice of the videophone is transmitted to the microphone 2.
Connect each to speaker 3.

In step 314, the audio interface section 4 is controlled,
Set a hold tone to the audio of a videophone call, and send the hold tone to the other party.

This completes the device settings for your own terminal.

In step 315, a mode switching RAS command is transmitted to notify the other party of the transmission mode of the own terminal. The contents of the command are transfer rate mode 1B, data mode 4.
8Kbit/s, audio transmission mode 4.8Kbit
/s, video transmission mode No video.

In step S16, the reception mode rate from terminal B is set to 1B.
In order to do so, a capability switching RAS command with the transfer rate capability set to 1B is sent to terminal B. Terminal B, which has received the capability switching RAS command for transfer rate capability IH, transmits to terminal A a mode switching RAS command for transfer rate mode 1B.

In step 317, a mode switching RAS command with the transfer rate mode set to 1B is received. In step 318, it is determined whether communication is being performed using 2B. If communication is in progress on 2B, the process advances to 519, and the D channel control unit 15 disconnects and restores the B channel that is not used for communication. Step S
22, the incoming call is accepted on the vacant B channel.

Figures 6 and 7 show the transfer rate mode in order of priority.
12 is a flowchart for explaining the operation of the in-channel control unit 16 when dropping from B to 1B.

FIG. 6 is a flowchart when the transmission mode is set according to the priority order of data transfer and audio, but video is not transmitted. FIG. 7 is a flowchart when setting the transmission mode in priority order of data transfer, audio, and video. That is, FIG. 7 shows a case where images are transmitted at the remaining transfer rate.

At step 330 in FIG. 6, it is determined whether data is being transmitted. If the data is being transmitted, the data transfer rate used for data transmission is secured (step 531).

If voice is being communicated and the remaining rate is available for assignment to voice (steps 332 and 533), then the remaining rate is assigned to voice (step 534).

Note that if data is not being transmitted in step 330, 64
kb i t/s (1B) is assigned to voice (step 535).

In step 340 of FIG. 7, it is determined whether data is being transmitted. If the data is being transmitted, the rate used for data transfer is secured (step 541). Next, in step S42, it is determined whether voice communication is in progress.

If audio is being transmitted, the audio transmission mode is 16Kbij/S.
is secured as the audio rate (step 544).

Step 545 to determine whether there are any remaining rates.
), if it exists, assign it to the video (step 546).
.

Next, other embodiments will be described.

In Figure 1, if the terminal has only handset 1 without microphone 2 and speaker 3, if handset 1 is used for a telephone call, there will be no voice input/output means for the videophone call, so the audio of the videophone call will contain a hold tone. may be sent.

Furthermore, when reducing the transfer rate mode of a videophone call, the assignment of audio priority may be eliminated.

Furthermore, when 1B is communicating with AV terminal B and the remaining 1B is connected to a telephone, and the terminal user is using the telephone, the image transmitted by the AV terminal may be a held image.

Furthermore, if there is an incoming call during 2B communication on a videophone, in the case of the above first embodiment, the transfer rate mode is set to 1.
I answered the call after disconnecting and restoring the free B channel.
The telephone may be placed on hold using the hold procedure of the T-Q932 ISDN supplementary service, and the call may be answered.

(Effects of the Invention) As explained above, the present invention provides a multimedia communication method in which multimedia information such as audio information, video information, data, etc. is multiplexed and mutually communicated. μml as audio codec
By using something other than aw, it is possible to use μmlaw as a telephone audio codec, which has the effect of making it possible to communicate videophone audio and telephone calls at the same time.

In addition, in a multimedia communication method that multiplexes multimedia information such as audio information, video information, data, etc. and communicates with each other, when reducing the transfer rate mode, data, image,
Decide in advance the priority order of voice transfer mode assignment,
By setting the transfer mode according to the priority order when assigning the transfer rate, it is possible to minimize the deterioration of the communication function due to the reduction of the transfer rate mode.

Furthermore, in a multimedia communication method that multiplexes multimedia information such as audio information, video information, data, etc. and communicates with each other, if there is an incoming call during videophone communication in transfer rate mode 2B, the videophone By reducing the transfer rate to 1B and accepting incoming telephone calls on the vacant B channel, there is an effect that simultaneous telephone and videophone operations are possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a multimedia communication device for explaining the present invention in detail, FIG. 2 is a block diagram showing the configuration of a voice encoding/decoding section in detail, and FIG. An explanatory diagram showing the procedure for negotiating with the other party's terminal, FIG. 4 is a flowchart for explaining the operation of the D channel control section when a telephone call is received, and FIG. 5 is a flowchart for explaining the operation of the in-channel control section when a telephone call is received. Flowchart for, No. 6
7 and 7 are flowcharts for explaining the operation when reducing the transfer rate. DESCRIPTION OF SYMBOLS 1... Handset, 2... Microphone, 3... Speaker, 4... Audio interface section, 5... Audio encoding/decoding section, 6... Camera, 7... Document camera, 8...
...Display section, 9...Video interface section, 10.
... video encoding/decoding section, 11... data terminal section,
12... Data interface section, 13... Operation section, 14... System control section, 15... D channel control section, 16... Inch channel control section, 17... Demultiplexing section, 18...Line interface section. Applicant Canon Inc. Company Representative Patent Attorney Toshihiko Watanabe

Claims (1)

[Claims] 1. In a multimedia communication method that multiplexes multimedia information such as audio information, video information, data, etc. and communicates with each other, μ-law is used as an audio codec for the videophone when the videophone and telephone operate simultaneously. A multimedia communication method characterized by using 2. In a multimedia communication method in which multimedia information such as audio information, video information, data, etc. is multiplexed and communicated with each other, when reducing the transfer rate mode, the priority order of transfer mode assignment of data, image, and audio is determined in advance. . A multimedia communication method, characterized in that a transfer mode is set according to the priority order when assigning a transfer rate. 3. In a multimedia communication method that multiplexes multimedia information such as audio information, video information, data, etc. and communicates with each other, if there is an incoming call during videophone communication in transfer rate mode 2B, the videophone Transfer rate 1
A multimedia communication method characterized by reducing the number of telephone calls to B channels and accepting incoming telephone calls on the vacant B channels.