JPH0738871A - Image transmitter for broadcast type conference - Google Patents

Abstract

PURPOSE:To obtain a television conference system which can broadcast a speech signal from a predetermined conference room to conference rooms at plural points and is simpler and less inexpensive than a conventional system. CONSTITUTION:This transmitter is equipped with TV CODECs 1 and 5 which has an image encoding function, a distributor 2 which distributes their transmission output signals to plural lines, plural line connection devices 31-3n which connect the distribution output to specified opposite sides through lines and receive signals from the opposite sides, and a switch 4 which switch the received signals in predetermined order and supplies them to the TV CODECs 1 and 5 together with a timing signal for switching. Then the TV CODECs 1 and 5 are controlled to stop a noise and an alarm, generated owing to a momentary break at the time of the switching of the received signals, for a certain period and send a refresh request to the opposite-side TV CODEC.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, there is a system for connecting a plurality of conference rooms to make a video conference between them. In such a video conference system, a conference system for multipoints is required in addition to the video conference terminal, which is expensive. In general, a multi-point video conference system sends a caller's image and audio signals to all conference rooms, and audio can be sent to all conference rooms regardless of which conference room the caller changes. It is a system that can switch the image and audio signals sent to all the meeting rooms accordingly.

For example, when a plurality of video conference rooms are installed in the head office and a plurality of branch offices, there is a great demand for the president's presentation and daily information transmission in the form of simultaneous broadcasting from the head office to the branch offices. . For such applications, it is sufficient if there is a function of distributing audio / image signals from a fixed conference terminal of a multipoint video conference system to a plurality of conference terminals. It is desirable to supply.

[0004]

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

A TV codec (coder and decoder) internationally standardized by CCITT is used as an image transmitting apparatus for transmitting and receiving images and sounds of a conventional video conference system, and is used between a transmitting side and a receiving side. If an error occurs in the code sent by, the image encoder on the transmission side must be refreshed to reproduce a complete image on the reception side. For this reason, in order to realize the above-mentioned purpose, not only the output of a predetermined conference terminal is distributed and sent to a plurality of conference rooms, but also data from a plurality of conference rooms is received and It is necessary to have a function of refreshing the image encoder on the transmitting side when there is a failure while monitoring the failure status and the status of the line. Such a function is called command refresh, and the TV codec has a periodic refresh function for periodically refreshing the image encoder. Therefore, if this is used, command refresh cannot be substituted, but periodic refresh is possible. Since the cycle is generally as long as several tens of seconds, it takes a long time until the image is completely restored, which is not practical.

[0006]

The apparatus of the present invention comprises an image coder for converting an image signal into a digital signal, a voice coder for converting an audio signal into a digital signal, the image coder and the audio coder. , A transmission interface for multiplexing both output signals and transmitting them 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 the output signal of the reception interface into an image signal Codec having a signal decoder and a voice decoder for decoding into a voice 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. Switching between a plurality of line connection devices that are connected and receive the reception signal from the other side, and the reception signals of the line connection device in a predetermined order Is supplied to the serial TV codec,
And a switching device that supplies a timing signal for switching to the TV codec, and controls the reception interface, the image decoder, and the audio decoder according to the switching timing signal to control the reception signal. Noises and alarms caused by momentary interruption at the time of switching are stopped for a certain period, and a refresh request is transmitted to the TV codec of the other party via the transmission interface.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, FIG. 2 is a connection diagram showing a method applying the embodiment, and FIG. 3 is a signal for explaining the operation of the present embodiment. It is a timing diagram.

As shown in FIG. 2, from the broadcast-type conference image transmission apparatus 8 according to the present invention, via the network 10,
The present embodiment will be described with respect to a system in which the image transmission devices 92 to 9n in a plurality of conference rooms are connected to each other so that they can be broadcast simultaneously.
When there is no broadcast, one-on-one conferences are possible between arbitrary conference rooms. The broadcast-type conference image transmission device 8 will be described below.

In FIG. 2, the input terminal 11 of the TV coder 1
The image signal from 1 is encoded by the image encoder 13, and the audio signal from the input terminal 12 is encoded by the audio encoder 14. The output signals of 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 transferred to the n line connection devices 31.
To 3n, and transmitted from the transmission ends 61 to 6n to the transmission path.

Received signals sent from a plurality (n) of conference rooms via transmission lines are input from the receiving ends 71 to 7n, received by the line connecting devices 31 to 3n, and supplied to the switch 4. . In the switching device 4, the n line connection devices 31 to 3n
Of the output signal of the
Output to the decoder 5. In the TV decoder 5, the switch 4
The output signal of 1 is demultiplexed by the reception 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 it as an image signal from the output end 51. The audio decoder 54 decodes the output signal of the reception interface 55 and outputs it as an audio signal from the output end 52.

The reception interface 55 detects a control signal such as a command refresh request or a line alarm from the reception signal from the other side and refreshes the image encoder 13. Since the output signal of the switching unit 4 switches the reception signals from the n other parties, the output signal of the reception interface 55 is the signals A1 to An received from the other party in sequence like the signal shown in FIG. It becomes the form that appears. This signal a causes disturbances a1 to an for a while immediately after switching by the signal b which is a switching pulse. Therefore, the image / sound is disturbed, all the detected signals such as the command refresh request signal are invalidated, and an alarm is issued. In order to prevent this, the signal b for switching in the switching device 4
Immediately after, the output of the reception interface 55 is prohibited to be output for a fixed time T, and during that time, the outputs of the audio decoder 54 and the image decoder 53 are fixed so that they become valid after the time T elapses. Therefore, the output signal of the reception 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 reception interface 55 is also valid after a lapse of time T from the switching time and is supplied to the image encoder 13. In addition, the signal b is multiplexed as a command refresh request signal for the transmission interface 15 and output to the other side.
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 to be longer than the unsteady period of the TV decoder 5 from the pulse timing of the switching signal b, and the normal operation is performed after the time T elapses. In addition to this, since the signal TV is required to refresh the TV coder of the other party, the T coder of the other party is transmitted via the TV coder 1.
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 structure and at a low cost as compared with the conventional multi-point video conference system.

[Brief description of drawings]

FIG. 1 is a block diagram of an 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 diagram for explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 TV coder 2 Distributor 4 Switching device 13 Image encoder 14 Voice encoder 15 Transmission interface 31-3n Line connection device

Claims (2)

[Claims] 1. An image coder for converting an image signal into a digital signal, a voice coder for converting a voice signal into a digital signal, and both output signals of the image coder and the voice coder are multiplexed to a transmission line. Outgoing interface to send,
TV having a receiving interface for separating an image digital signal and an audio digital signal received from the transmission path, an image decoder for decoding an output signal of the receiving interface into an image signal, and an audio decoder for decoding into an audio signal
A codec, a distributor that distributes a plurality of transmission output signals of the TV codec, and a plurality of distributors that connect each output signal of the distributor to a designated partner via a line and receive a received signal from the partner. A line connection device; and a switching device that switches a reception signal of the line connection device in a predetermined order and supplies the same to the TV codec, and also supplies a switching timing signal to the TV codec. The reception interface, the image decoder, and the audio decoder are controlled according to a switching timing signal, noise and alarm generated by a momentary interruption at the time of switching the reception signal are stopped for a certain period, and the transmission interface is used. An image transmission device for broadcast type conference, which transmits a refresh request to a TV codec of the other party. 2. The stop period at the time of switching the reception signal is
2. The image transmission apparatus for broadcast type conference according to claim 1, wherein the image transmission apparatus is set to be longer than a non-stationary period associated with the switching of the TV codec.