JP2992573B2 - Video Phone / Video Conference Equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a videophone / videoconference apparatus which encodes an image signal and a voice signal, multiplexes them, sends them out to a communication line, and realizes face-to-face communication with a remote place.
The use convenience is improved.

[0002]

2. Description of the Related Art The configuration of a general videophone / videoconference device is shown in FIG. An analog image signal a1 output from the camera 11 is converted into a digital image signal b by an analog / digital converter (hereinafter abbreviated as A / D converter) 21.
It becomes 1. The digital image signal b1 is format-converted by the format converter 22 and then converted by the image encoder 3.
1 and becomes encoded image data c1.

A handset 12 or a microphone 13
The analog audio signal a2 output from the A / D converter 23 becomes a digital audio signal b2. The digital audio signal b2 is encoded by the audio encoder 32 to become encoded audio data c2. The coded image data c1 and the coded audio data c2 are multiplexed by the data multiplexing unit 41,
Communication line 60 through ISDN interface unit 50
Sent to

The signal received from the communication line 60 is
Through the ISDN interface unit 50, the data separation unit 4
2, the image data is separated into encoded image data c3 and encoded audio data c4. Note that the coded image data c3 and the coded audio data c4 are the coded image data c1,
This is a signal having the same contents as the encoded audio data c2.

[0005] The received encoded image data c3 is decoded by an image decoder 33, and is inversely format-converted by a format inverse conversion unit 24, to obtain a digital decoded image signal b.
It becomes 3. The digital decoded image signal b3 is converted into an analog decoded image signal a3 by the D / A converter 25 and output to the monitor 14.

On the other hand, the received encoded voice data c4 is
The audio signal is decoded by the audio decoder 34 and becomes a digital decoded audio signal b4. The digital decoded audio signal b4 is D / A
The converted signal is converted into an analog decoded audio signal a4 by the conversion unit 26 and output to the handset 12 or the speaker 15.

[0007] As an encoding method of the image signal in the image encoder 31, H.264 of CCITT (International Telegraph and Telephone Consultative Committee) recommendation. The H.261 system is common. Also, H.
In the H.261 system, the resolution of a Common Intermediate Format (hereinafter abbreviated as CIF) image and the resolution of a CIF image are set to 1 /
Since a 1/4 CIF (Quarter CIF: hereinafter abbreviated as QCIF) image is specified, the format conversion unit 2
In step 2, the input digital image signal b1 is
Image or QCIF image.

[0008] The encoding method of the audio signal in the audio encoder 32 is described in G. 711 system, G. The 722 system has been standardized. G. FIG. The 711 system is 3.4 kHz.
This is a method for compressing audio signals in the z band to 64 kbit / s (bit / second: abbreviated as b / s). The 722 system is a system for compressing a 7 kHz band audio signal to 64 kb / s. Standardization of an encoding method for compressing an audio signal to 16 kb / s is in progress, and there are various other encoding methods. If a non-standard protocol specified in H.221 is used, a non-standard coding method can be used between specific terminals.

[0009] The transmission speed of the available communication line is also
m × 64 kb / s (m = 1 to 6) or n × 384
It is variable up to kb / s (n = 1 to 5). It is up to each terminal to determine which of the various image formats, coding schemes, and communication speeds to implement, so there are videophone / videoconference devices with different capabilities. Therefore, an in-channel capability exchange procedure for realizing an interconnection between two terminals having different capabilities is described in CCITT Recommendation H.264. 242.

That is, a channel of a communication line is divided into 640 bits to form a unit of one frame, and a bit at a specific position in this frame is defined as a bit rate allocation signal (hereinafter abbreviated as BAS). I do. Then, at the start of the communication and during the communication, the capability of the own terminal is transmitted to the other terminal using the BAS which is the in-channel information (the content that can be represented by the BAS is specified in Recommendation H.221).

The terminal that has received the BAS can know the capability of the partner terminal by interpreting the value of the BAS. Then, communication starts with the common capability of both terminals. However, if there are multiple common capabilities or if both terminals can support a high line speed, which operation mode is actually used (Image format / coding method / communication speed) It is free to perform communication.

Therefore, the actual operation mode is also notified from the transmission side to the reception side using BAS as an operation command. On the receiving side, the transmitted BAS value is interpreted, the operating mode of the transmitting side is known, and the circuit on the receiving side is matched with the mode and decoded. This procedure can be used not only to determine the communication mode at the start of communication, but also to change the communication mode during communication.

However, conventionally, when the speech encoding mode is changed on the transmission side, an impulsive sound is generated from the speaker 15 or the handset 12 when the speech decoder is switched on the reception side, and the user is extremely inconvenient. There was a problem of giving pleasure. Also, when changing the image format on the sending side, the image is temporarily distorted on the receiving side,
There was a problem that the user was uncomfortable.

As a method for solving the above problem, a method of stopping the reproduction of the received voice or the received image when the communication mode is changed can be considered. However, in this case, if the reproduction stop time of the sound or the image is too long, there is a problem that the psychological burden on the user increases and the usability deteriorates. For this reason, it is necessary to minimize the time required for stopping the reproduction, and for that purpose, there is a technical problem in what timing and how long the reproduction should be stopped.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of changing a communication mode, which is performed in advance by receiving an operation command signal transmitted from a partner terminal indicating the change of the communication mode. It is an object of the present invention to stop the reproduction of the received voice for a predetermined period of time and prevent the generation of an impact sound due to the switching of the voice decoder.

Further, upon receiving an operation command signal indicating a change in the communication mode or receiving a code indicating a change in the image format, the display of the received image is stopped for a certain period of time, and when the communication mode is changed or the image format is switched. To prevent the received image from being disturbed.

[0017]

FIG. 1 is a block diagram showing the principle of the present invention. In FIG. 1, reference numeral 1 denotes a command receiving unit for interpreting an in-channel operation command signal sent from the transmission side, and 2 denotes an operation control unit for controlling a decoding operation based on the received operation command. Further, the present invention has a sound reproduction control means 5 for controlling reproduction / stop of the received sound, and a stop pattern storage means 4 for storing a change pattern of an operation command for stopping the received sound.

In the present invention, the communication mode is changed immediately after receiving the operation command signal indicating the switching of the communication mode using the BAS or the like from the partner terminal. When the received command is set in the stop pattern storage means 4 when the operation command signal indicating the change of the operation is received, the received sound is transmitted to the user by the sound reproduction control means 5 .
The preset time or the end of the speech decoder switchover.
Erase until completion .

For example, when "(usable) speech encoding mode" is set in the stop pattern storage unit,
Upon receiving the operation command signal for changing the voice encoding mode, the reproduction of the received voice is stopped for a certain period of time, and the reproduction of the voice is restarted after a certain period of time.

FIG. 2 shows how the sound reproduction is stopped and restarted. As a result, the sound can be erased for a period of time from when the operation command for changing the audio encoding mode is received to when the audio decoder is actually switched, and generation of an impact sound due to the switching of the audio decoder can be prevented. It becomes possible.
At this time, the time at which the reproduction of the sound is stopped is a time set in advance according to the characteristics of the apparatus. As a result, it is possible to stop the reproduction of the audio for the minimum necessary time and resume the reproduction of the audio after that.

The time required for switching the audio decoder after receiving the operation command signal may differ depending on each device. Therefore, the present invention provides a
There is a setting means 3 that allows the user to set the reception voice stop time, and this is dealt with.

Further, depending on the device, switching of the speech encoder is performed not only when an operation command signal for changing the speech encoding mode is received, but also when the communication speed is changed or when another communication mode is changed. there is a possibility. In view of this, the present invention copes with this by allowing the user to set the stop pattern stored in the stop pattern storage means 4 by the setting means 3.

The present invention also has a switching end notifying means 6 for notifying the audio reproduction control means 5 of the end of the switching of the audio decoder on the receiving side. I do. In this case, it is possible to further shorten the audio reproduction stop time.

Further, the present invention has an image display control means 7 for controlling the display / stop of the received image, and performs not only the reception sound but also the stop of the display of the received image separately. As a result, it is possible to prevent disturbance of the received image due to the change in the communication mode or the change in the image format.

[0025]

Operation As shown in FIG. 2, it is assumed that transmission and reception are performed between terminal X and terminal Y. For example, when the terminal X transmits an operation command indicating a change in the communication mode and the terminal Y receives the operation command, the terminal Y checks the stop pattern set in the stop pattern storage means 4, and if there is a voice command, outputs a voice command. Stop playback. Then, switching of the audio decoder is started. After transmitting the operation command indicating the change of the communication mode, the terminal X starts transmission in the changed mode. The terminal Y resumes the audio reproduction received in the changed mode after stopping the audio reproduction for a certain period of time or after the switching by the audio decoder ends.

As described above, according to the present invention, when the received command is set in the stop pattern storage means 4 when the communication mode is changed, the operation command signal transmitted from the partner terminal indicating the communication mode change is transmitted. As a result, the reproduction of the received sound is stopped for a time necessary for noise elimination, and the generation of an impact sound due to the switching of the sound decoder can be prevented.

The receiving voice stop time can be set by the user by the setting means 3 . Further, the user can set a stop pattern to be stored in the stop pattern storage means 4.

Further, upon receiving an operation command signal indicating a change in communication mode or receiving a code indicating a change in image format, the display of the received image is stopped for a certain period of time, and when the communication mode is changed or the image format is switched. Of the received image can be prevented.

[0029]

FIG. 3 shows a first embodiment of the present invention. In the figure,
The blocks and signals with the same numbers as in FIG. 7 are the same as those described in the description of FIG.

In this embodiment, the digital audio signal b2 is transmitted to the audio encoder switching unit 81 among the audio encoders 32a, 32b and 32c.
The encoder according to the instruction is selected and encoded, and becomes encoded audio data c2. The switching of the speech encoder is performed according to an instruction from the control unit 70. The voice encoding mode at this time is transmitted from the communication control unit 90 as an in-channel operation command d1.

On the receiving side, after separating the data, the communication control unit 9
At 0, the in-channel operation command d1 is analyzed. In response to this, the control unit 70 sets the audio decoder switching unit 82
Is instructed to select a decoder that matches the operation command d1 among the speech decoders 34a, 34b, and 34c.

The control unit 70 simultaneously refers to the stop pattern storage unit 83 and, if there is a selected audio encoding mode, notifies the audio reproduction control unit 84 of an audio reproduction stop command d2. . In the case of the present embodiment, it is assumed that a speech encoding mode that can be decoded by the present apparatus is stored in the stop pattern storage unit 83 in advance. In response, the sound reproduction control unit 84 stops outputting sound for T seconds. The value of this T is can be changed using a user according to the characteristics of the device. Then, after T seconds, the reproduction of the sound is started, and the communication is started.

Similarly, when the speech encoding mode is changed during communication, the in-channel operation command d
1 until it switches to a matching speech decoder.
The sound reproduction control unit 84 stops outputting sound for T seconds.

Therefore, in the present embodiment, the sound reproduction is stopped when the audio decoder is switched at the start of communication and during communication, so that the impulsive sound when the decoder is switched is transmitted from the handset 12 or the speaker 15. It does not occur.

In this embodiment, the audio reproduction controller 84 is installed between the D / A converter 26 and the handset 12 or the speaker 15, but the audio decoders 34a to 34a
4c and the D / A conversion section 26.

FIG. 4 shows a second embodiment of the present invention. In the figure, blocks and signals assigned the same numbers as those in FIGS. 3 and 7 are the same as those described in the description of FIGS.

In this embodiment, the configuration is such that the user can change the setting contents of the stop pattern storage unit 83 by inputting to the control unit 70 from the operation unit 16 before starting communication. That is, in the first embodiment, usable speech coding modes are stored, but in the present embodiment, for example, usable line speeds are added thereto. Then, if the change of the line speed is instructed after the communication is started in the same manner as in the first embodiment, the sound reproduction control is performed in the same manner as in the first embodiment upon receiving the operation command d1. The reproduction of the sound is stopped for T seconds by the section 84 to prevent the generation of noise due to the line switching.

Further, it is also possible to add a low-speed and a high-speed data speed other than the image and the voice to the stop pattern storage unit 83. In that case, the reproduction of the sound is stopped when the corresponding data rate is turned on.

FIG. 5 shows a third embodiment of the present invention. In the figure, blocks and signals given the same numbers as those in FIGS. 3, 4, and 7 are the same as those described in the description of FIGS. 3, 4, and 7, and therefore description thereof is omitted.

In this embodiment, similarly to the first and second embodiments, when the in-channel operation command d1 matches the contents of the stop pattern storage unit 83, the control unit 70
Is a sound reproduction stop command d2 to the sound reproduction control unit 84.
And stop the reproduction of the received voice. When the switching of the audio decoder is completed and the audio can be decoded in the changed communication mode, the audio decoder switching unit 82 outputs the audio to the audio reproduction control unit 84. The stop release command d3 is notified, and the reproduction of the received voice is resumed.

FIG. 6 shows a fourth embodiment of the present invention. In the figure, blocks and signals assigned the same numbers as those in FIGS. 3 to 5 and 7 are the same as those described in the description of FIGS.

In this embodiment, the digital image signal b1 is converted by the format converter 22 into the CIF signal b11 or the QCIF signal b1 in accordance with an instruction from the controller 70.
It becomes 2. Next, H.264 is performed by the image encoder 31. H.261, and becomes encoded image data c1. Then, a frame start code is added to each frame and the frame is transmitted.
And are different.

On the receiving side, the image decoder 33
The frame start code is inspected for each frame and decoded in a matching format to become a decoded CIF signal b31 or a decoded QCIF signal b32. Then, the image format of the frame is notified to the format inverse conversion unit 24 via the control unit 70, and the matched digital decoded image signal b3
Get.

At this time, if the image format is changed, the control unit 70 notifies the image display control unit 85 of the image display stop command d4. Upon receiving the notification, the image display control unit 85 stops displaying the image for T2 seconds. This T2
Is a value predetermined according to the characteristics of the apparatus, but can be changed by the user.

Therefore, in this embodiment, the image is not disturbed when the image format is changed. In the present embodiment, the image display control unit 85 includes the D / A conversion unit 25.
Although it is installed between the monitor 14 and the monitor 14, it can be installed between the format reverse conversion unit 24 and the D / A conversion unit 25.

[0046]

As described above, according to the present invention,
When the received command is set in the stop pattern storage unit when the communication mode is changed, the short command necessary for noise elimination is triggered by the reception of the operation command signal transmitted from the partner terminal indicating the communication mode change. It is possible to stop the reproduction of the time- reception voice and prevent the generation of an impact sound due to the switching of the voice decoder.

Further, the user can set the reception voice stop time, and can cope with the time required for switching the voice decoder depending on the device. Also,
The stop pattern stored in the stop pattern storage unit can be set by the user.

Also, upon receiving an operation command signal indicating a change in the communication mode or receiving a code indicating a change in the image format, the display of the received image is stopped for a certain period of time, and when the communication mode is changed or the image format is switched. It is possible to prevent disturbance of the received image at the time.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a diagram showing a state of audio playback stop-resume according to an embodiment of the present invention.

FIG. 3 is a diagram showing a first embodiment of the present invention.

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a diagram showing a third embodiment of the present invention.

FIG. 6 is a diagram showing a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of a general videophone / videoconference device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Command receiving means 2 Operation control means 3 Setting means 4 Stop pattern storage means 5 Audio reproduction control means 6 Switching end notification means 7 Image display control means a1 Analog image signal a2 Analog audio signal a3 Analog decoded image signal a4 Analog decoded audio signal b1 Digital image signal b2 Digital audio signal b3 Digital decoded image signal b4 Digital decoded audio signal b11 CIF signal b12 QCIF signal b31 Decoded CIF signal b32 Decoded QCIF signal c1 Encoded image data c2 Encoded audio data c3 Encoded image data c4 Encoded audio Data d1 In-channel operation command d2 Voice playback stop command d3 Voice playback stop release command d4 Image display stop command

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Matsui 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Tsutomu Irishima 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Japan (56) References JP-A-2-182910 (JP, A) JP-A 64-105627 (JP, A) JP-A 4-1688893 (JP, A) (58) Fields investigated ( Int.Cl. ⁶ , DB name) H04N ^7/ 14-7/15 H04M 3/56

Claims (2)

(57) [Claims] A command receiving means for interpreting an in-channel operation command signal transmitted from a transmitting side;
An operation control means (2) for controlling a decoding operation in accordance with the received operation command, and when the operation command is received at the start of communication or when the operation command is received at the time of changing the communication mode during communication, Then, the communication mode is switched, decoding starts in an operation that matches the communication mode of the partner terminal, and the decoded videophone / videoconference device receives the decoded reception based on the instruction from the operation control means (2).
Voice reproduction control means for controlling the stop / start of the output of the transmission voice
(5) and a stop pattern storing means (not shown) for storing, as a stop pattern, information indicating an operation command for stopping the received voice among the operation commands for switching the communication mode, and storing a stop time of the received voice. and 4) restored the stopping pattern and the received audio stop time, and setting means for setting the user (3), in accordance received encoded audio data to the encoding method
A plurality of kinds of speech decoder for issue, said operating system
The plurality of types of speech decoding based on the control of the control means (2).
A voice decoder switching means for switching the communication device, wherein when the operation command indicating the switching of the communication mode is received from the other party, the received command is set in the stop pattern storage means (4). The operation control
The means (2) is provided to the sound reproduction control means (5) with the stop.
Stop received voice set in stop pattern storage means (4)
Stop outputting decoded audio for only the time
And the received command further
In the case of a command indicating a change of the audio decoder, the command
Operation control means (2) is provided for the audio decoder switching means.
And a video telephone / video conference apparatus for controlling the switching of the audio decoder . 2. An image display control means for controlling display / stop of a received image in the videophone / videoconference device according to claim 1.
Video telephone / television, characterized in that the display of the received image is stopped for a predetermined time when the communication mode or the image format is changed, separately from the reproduction / stop control of the received sound. Conference equipment.