JP2891045B2 - Broadcast-type conference image transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transmission apparatus for a broadcast conference.

[0002]

2. Description of the Related Art Conventionally, there is a system for connecting a plurality of conference rooms and holding a video conference between them. Such a video conference system requires a multipoint conference system in addition to the video conference terminal, which is expensive. In general, a multipoint video conferencing system sends a caller's image and audio signals to all conference rooms, and voice can be transmitted to all conference rooms by speaking in any conference room, and the caller changes. And a video and audio signal to be sent to all conference rooms in response to the request.

[0003] For example, when a plurality of video conference rooms are installed in a head office and a plurality of branches, there is a great demand for a presentation by the president and daily information transmission in a form of simultaneous broadcasting from the head office to the branches. . In such applications, a function to distribute audio and video signals from a fixed conference terminal of a multipoint video conference system to a plurality of conference terminals may be used. It is desirable to supply.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a broadcast-type conference image broadcasting apparatus capable of simultaneously broadcasting images and sounds from a predetermined conference room to a plurality of conference rooms at a lower cost than before. It is to provide in.

[0005] A TV codec (coder and decoder) internationally standardized by CCITT is used as an image transmission apparatus for transmitting and receiving images and voices in a conventional video conference system. When an error occurs in the code sent in the step (1), unless the image encoder on the transmitting side is refreshed, a complete image cannot be reproduced on the receiving side. Therefore, in order to achieve the above object, not only is the output of a predetermined conference terminal distributed and sent to a plurality of conference rooms, but also data from a plurality of conference rooms is received, and A function of refreshing the image encoder on the transmitting side is required when there is a failure while monitoring the failure status and the line status. Such a function is called a command refresh, and the TV codec has a periodic refresh function of periodically refreshing the image encoder. Therefore, if this function is used, the command refresh cannot be performed instead. Is generally as long as several tens of seconds, and it takes a long time until the image is completely recovered, which is not practical.

[0006]

According to the present invention, there is provided an image encoder for converting an image signal into a digital signal, an audio encoder for converting an audio signal into a digital signal, the image encoder and the audio encoder. A transmission interface for multiplexing both output signals of the transmission interface and transmitting the transmission signal to a transmission path, a reception interface for separating an image digital signal and an audio digital signal received from the transmission path, and an image decoding for decoding an output signal of the reception interface into an image signal TV codec having a decoder and an audio decoder for decoding to an audio signal, a distributor for distributing a plurality of transmission output signals of the TV codec, and each output signal of the distributor to a designated partner via a line. A plurality of line connection devices that connect and receive a reception signal from the other party, and switch the reception signals of the line connection devices in a predetermined order. Is supplied to the serial TV codec,
And a switching unit that supplies a switching timing signal to the TV codec, and controls the reception interface, the image decoder, and the audio decoder in accordance with the switching timing signal, and controls the reception signal. A noise or an alarm caused by an instantaneous interruption at the time of switching is stopped for a certain period, and a refresh request is transmitted to the other party's TV codec via the transmission interface.

[0007]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a connection diagram showing a system to which the embodiment is applied, and FIG. 3 is a signal for explaining the operation of the embodiment. It is a timing chart.

As shown in FIG. 2, a broadcast-type conference image transmission apparatus 8 according to the present invention
The present embodiment will be described with respect to a system in which the image transmission devices 92 to 9n of a plurality of conference rooms are connected and can be broadcast simultaneously.
When there is no simultaneous broadcast, a one-on-one conference between arbitrary conference rooms is possible. The broadcast type conference image transmission device 8 will be described below.

In FIG. 2, the input terminal 11 of the TV coder 1
Is encoded by an image encoder 13, and the audio signal from the input terminal 12 is encoded by an audio encoder 14. Output signals from the encoders 13 and 14 are multiplexed by the transmission interface 15 and sent to the distributor 2. Distributor 2
Then, the output signal of the TV coder 1 is converted into n line connection devices 31.
To 3n, and sent from the transmission ends 61 to 6n to the transmission path.

Received signals transmitted from a plurality of (n) conference rooms via transmission paths are input from receiving ends 71 to 7n, received by line connection devices 31 to 3n, and supplied to switch 4. . In the switch 4, n line connection devices 31 to 3n
Output signals are sequentially switched, and together with the switching signals,
Output to the decoder 5. In the TV decoder 5, the switch 4
Are demultiplexed by the receiving interface 55 and supplied to the image decoder 53 and the audio decoder 54. The image decoder 53 decodes the output signal of the reception interface 55 and outputs the decoded signal from the output terminal 51 as an image signal. Further, the audio decoder 54 decodes the output signal of the reception interface 55 and outputs it from the output terminal 52 as an audio signal.

The receiving interface 55 detects a control signal such as a command refresh request or a line alarm from a received signal from the other party, and refreshes the image encoder 13. Since the output signal of the switch 4 switches the reception signals from the n counterparts, the output signals of the reception interface 55 include the signals A1 to An received from the counterpart sequentially as shown in FIG. It will be in the form that appears. The signal a is disturbed for a while immediately after switching by the signal b which is a switching pulse. For this reason, the image and the sound are disturbed, all the detected signals such as the command refresh request signal are invalidated, and an alarm is generated. In order to prevent this, the signal b for switching in the switch 4
Immediately after the above, the output of the receiving interface 55 is prohibited from being transmitted for a certain time T, and during that time, the outputs of the audio decoder 54 and the image decoder 53 are fixed so that the output becomes valid after the elapse of the time T. For this reason, the output signal of the receiving interface 55 is fixed to the value at the time of switching as in the signal of FIG. The command refresh request signal from the receiving interface 55 is also valid after a lapse of time T from the switching time, and is supplied to the image encoder 13. Also, the signal b is multiplexed as a command refresh request signal by the transmission interface 15 and output to the other party.
The TV coder 1 and the TV decoder 5 have a CCITT standardized codec function.

As described above, the operation of the TV decoder 5 is invalidated at the time T set longer than the non-stationary period of the TV decoder 5 from the pulse timing of the switching signal b, and the normal operation is resumed after the elapse of the time T. In addition, since the refresh is required by the signal b to the TV coder of the other party, the TV coder 1 of the other party
A refresh request signal is transmitted to the V coder.

[0014]

As described above, according to the present invention, a broadcast type video conference can be realized with a simple configuration and at a low cost as compared with a conventional multipoint video conference system.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a system to which an embodiment of the present invention is applied;

FIG. 3 is a signal timing chart for explaining the operation of the embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 TV coder 2 distributor 4 switch 13 image encoder 14 audio encoder 15 transmission interface 31 to 3n line connection device

Claims (2)

(57) [Claims] An image encoder for converting an image signal into a digital signal, an audio encoder for converting an audio signal into a digital signal, and multiplexing both output signals of the image encoder and the audio encoder to a transmission path. A sending interface to send,
A TV having a receiving interface for separating an image digital signal and an audio digital signal received from the transmission line, an image decoder for decoding an output signal of the receiving interface into an image signal, and an audio decoder for decoding to an audio signal
A codec; a distributor for distributing a plurality of transmission output signals of the TV codec; and a plurality of receivers for connecting each output signal of the distributor to a designated partner via a line and receiving a reception signal from the partner. A line connection device, and the switching device that switches a reception signal of the line connection device to the TV codec by switching the signal in a predetermined order and supplies a switching timing signal to the TV codec; The receiving interface, the image decoder, and the audio decoder are controlled in accordance with the switching timing signal, and a noise or an alarm caused by an instantaneous interruption at the time of switching the received signal is stopped for a certain period of time, via the transmission interface. An image transmitting apparatus for a broadcast-type conference, wherein a refreshing request is transmitted to a TV codec on the other side. 2. The suspension period at the time of switching the reception signal,
2. The image transmission device for a broadcast conference according to claim 1, wherein the image transmission device is set to be longer than an unsteady period accompanying the switching of the TV codec.