JPH07177484A - Inter-multi-point communication controller - Google Patents

Abstract

PURPOSE:To reduce a time when a disturbed video image is displayed by requesting transmission of in-frame coded video data to a sender source video conference terminal equipment when an error of video data in excess of the correction capability of a BCH code are detected. CONSTITUTION:When an error in excess of error correction capability of a BCH code takes place in BCH decoding processing, BCH decoding sections 10a-10m send an error correction disable signal to a system control section 2. The control section 2 receives the signal and allows an in-frame request transmission section 11 to send an in-frame request to a sender video conference terminal equipment. Thus, the video conference terminal equipment sends in- frame video data and a picture of a receiver side video conference terminal equipment is restored to a correct picture. Or a filler bit transmission command is outputted to the sender source terminal equipment and the received picture is frozen before a disturbed video image is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multipoint communication control apparatus for realizing a simultaneous multipoint video conference between a plurality of video conference terminals.

[0002]

2. Description of the Related Art FIG. 10 shows, for example, JP-A-1-286689.
FIG. 11 is a block diagram showing a conventional multipoint communication control device disclosed in Japanese Patent Publication No. In the figure, 1 is the multipoint communication control device, and 2 is a system control unit that controls and manages the whole. Reference numeral 3 denotes an interface section (hereinafter referred to as a line I / F section) with a line connecting any three or more video conference terminals (not shown).

Reference numerals 4a to 4m denote multiplexing units for multiplexing video data, audio data, and general-purpose data to be transmitted to the video conference terminals, and 5a to 5m denote multiplexed data received from the video conference terminals. A separation unit that separates video data, audio data, and general-purpose data.

A multiplexer 6 selects one of the video data separated by the separators 5a to 5m and multiplexes 4a to 4m.
7 is a video switching unit for sending to each of the separating units 5a to 5m, which synthesizes all voice data, generates voice data by subtracting the voice of the own station from the synthesized voice data, and multiplexes each. A voice control unit for sending to the units 4a to 4m,
A general-purpose data port control unit 8 controls the general-purpose data separated by the separation units 5a to 5m.

Next, the operation will be described. Among the video conference terminals connected to the line I / F unit 3 via the line, the video conference terminal (parent terminal) that intends to hold the conference is not connected to the multipoint communication control device 1 by which video conference terminal. Indicate whether you want to hold a multipoint meeting.

When the system control unit 2 receives the request, it instructs the line I / F unit 3 to call the specified video conference terminal. When the line between each called video conference terminal and the multipoint communication control device 1 is connected, transmission and reception of multiplexed data in which video data, audio data and general-purpose data are multiplexed is performed, The video conference starts.

The multiplexed data transmitted from each video conference terminal is received by the line I / F unit 3 and then passed to the corresponding demultiplexing units 5a to 5m, where the video data,
Separated into audio data and general-purpose data, the video data is passed to the video switching unit 6, the audio data is passed to the audio control unit 7, and the general-purpose data is passed to the general-purpose data port control unit 8.

When the video switching unit 6 receives the video data from the separating units 5a to 5m, one of them is selected according to the instruction of the system control unit 2 and the selected video data is sent to the multiplexing units 4a to 4m. To deliver. The video data distributed at this time is BCH-encoded as shown in FIG.
The frame has an error correction frame structure in which 1-bit frame pattern bits S _{1 to} Sn are added to the head.

Since the video data is BCH-encoded here, even if the received video data has an error, BC
By decoding the H code, error correction is possible, but if an error that exceeds the correction capability of the BCH code occurs, it becomes uncorrectable, and video data in an erroneous state is distributed to each multiplexing unit.

Further, in the voice control unit 7, the separation units 5a-5
All voice data sent from m are synthesized, and then voice data obtained by subtracting the voice of the own station from the synthesized voice data is generated and sent to each of the multiplexing units 4a to 4m.

Similarly, the general-purpose data separated by each of the separation units 5a-5m is sent to the general-purpose data port control unit 8,
The general-purpose data selected from among them is returned to each multiplexing unit 4a again.
It is sent to ~ 4m and used for control data of each video conference terminal.

[0012]

Since the conventional multipoint-to-point communication control apparatus is constructed as described above, it may be affected by a disturbance or the like generated in the transmission line between the video conference terminal and the multipoint-point communication control apparatus. If an error occurs in the transmitted data and the received video data has an error that exceeds the correction capability of the BCH code, the erroneous video data is distributed to each video conference terminal, and the distorted video is displayed on the video conference terminal. Therefore, there was a problem that the operation of the video conference becomes difficult.

The present invention has been made to solve the above problems, and shortens the time during which a distorted image is displayed on the video conference terminal when the image data exceeds the correction capability of the BCH code. To do. Another object of the present invention is to obtain a multipoint communication control device that freezes an image before a distorted image is displayed.

[0014]

A multipoint-to-point communication control apparatus according to the present invention comprises a plurality of separation units for processing video data, audio data and general-purpose data from a plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device for realizing a simultaneous multipoint video conference between the plurality of video conference terminals, the multi-point communication control device is separated by the separation unit, and BC
Decode the BCH code of the H-encoded video data to BC
When an error in the video data that exceeds the correction capability of the H code occurs, the error correction impossible state is detected for the video data to recognize that the incorrect video data is delivered to the video conference terminal on the receiving side. An in-frame request transmission unit for requesting the transmission source video conference terminal to transmit the intra-frame encoded video data is provided, and the video of the receiving side video conference terminal is restored to a correct video.

[0015] Further, the simultaneous multipoint TV between the plurality of video conference terminals is provided with a plurality of separation units for processing video data, audio data and general-purpose data from the plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, B is separated by the separation unit.
BCH code of CH encoded video data is decoded to
When an error occurs in the video data that exceeds the correction capability of the CH code, an error correction impossible state is detected for the video data, and the filler bit as the video data that is not decoded is transmitted to the video conference terminal of the transmission source. A filler bit sending unit is provided to freeze the video before the disturbed video is displayed on the receiving side video conference terminal.

Further, a simultaneous multipoint television between the plurality of video conference terminals is provided, which comprises a plurality of separation units for processing video data, audio data and general-purpose data from the plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, B is separated by the separation unit.
BCH code of CH encoded video data is decoded to
When an error occurs in the video data that exceeds the correction capability of the CH code, an error correction impossible state is detected for the video data, and a filler bit as the video data that is not decoded is transmitted to the video conference terminal of the transmission source. A filler bit sending unit is provided to freeze the video before the disturbed video is displayed on the receiving video conference terminal, and an intra-frame request sending unit to request the transmission of intra-frame encoded video data is provided. The video of the video conference terminal is restored to the correct video.

[0017] Further, the multi-point simultaneous television between the plurality of video conference terminals includes a plurality of separation units for processing video data, audio data and general-purpose data from the plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, B is separated by the separation unit.
When decoding a BCH code of CH-encoded video data, in order to detect the beginning of the BCH code, a frame pattern bit is detected from error correction frame data generated based on a predetermined regularity, and the corresponding When it is recognized that the frame pattern bit has disappeared, an error correction frame synchronization control unit for instructing the transmission source video conference terminal to request transmission of the intra-frame encoded video data is provided.

[0018] Further, the multi-point simultaneous television between the plurality of video conference terminals is provided with a plurality of separation units for processing video data, audio data and general-purpose data from the plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, B is separated by the separation unit.
When decoding a BCH code of CH-encoded video data, in order to detect the beginning of the BCH code, a frame pattern bit is detected from error correction frame data generated based on a predetermined regularity, and the corresponding When it is recognized that the frame pattern bits have disappeared, an error correction frame synchronization control unit is provided to instruct the transmission source video conference terminal to send out filler bits as video data that is not decoded.

[0021] Further, the multi-point simultaneous television provided between the plurality of video conference terminals includes a plurality of separation units for processing video data, audio data and general-purpose data from the plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, B is separated by the separation unit.
When decoding a BCH code of CH-encoded video data, in order to detect the beginning of the BCH code, a frame pattern bit is detected from error correction frame data generated based on a predetermined regularity, and the corresponding When recognizing that the frame pattern bit has disappeared, an error that instructs the sender's video conference terminal to send out filler bits as undecoded video data and a request to send intra-frame encoded video data A correction frame synchronization control unit is provided.

Further, in the error frame synchronization control unit, the forward protection stage number setting circuit for setting the forward protection stage number in the error correction frame synchronization control unit in order to lose the synchronization only when the frame pattern bits are continuously lost. And a comparison circuit for comparing the set value with the number of times of frame pattern bit loss.

[0021]

The intra-frame request sending unit according to the present invention detects that the video data exceeds the correction capability of the BCH code, thereby detecting in advance that erroneous video data is delivered to the video conference terminal, and transmits the video conference terminal. By requesting the original video conference terminal to transmit the intra-frame encoded video data, the time required to restore the disordered video displayed on each video conference terminal to a correct video becomes short.

Further, the filler bit sending unit detects that the video data exceeds the correction capability of the BCH code, thereby detecting in advance that wrong video data is delivered to the video conference terminal, and the sender video conference. Sending filler bits to the terminal, which means video data not to be decoded,
Since the video is frozen before the distorted video is displayed on each video conference terminal, the display of the distorted video is prevented in advance.

Further, by providing the intra-frame request sending unit and the filler bit sending unit at the same time in the multipoint communication control device, it is possible to make a mistake in advance by detecting that the video data exceeds the correction capability of the BCH code. Video that is detected to be delivered to video conferencing terminals, requests the source video conferencing terminal to transmit intra-frame encoded video, sends out filler bits, and is displayed on each video conferencing terminal. The restoration time will be shorter and the image will be frozen during that time so that no disturbing image is displayed.

Further, the error correction frame synchronization control unit provided in the BCH decoding unit detects that the error correction frame pattern bit of the video data has disappeared, so that erroneous video data is distributed in advance to the video conference terminal. In response to the request, the intra-frame request sending unit restores the distorted video displayed on each video conference terminal by requesting the source video conference terminal to transmit the intra-frame encoded video data. The time gets shorter.

Further, the error correction frame synchronization control unit provided in the BCH decoding unit detects that the error correction frame pattern bit of the video data has disappeared, so that erroneous video data is distributed in advance to the video conference terminal. The filler bit sending unit sends the filler bit to the transmission source video conference terminal to freeze the video before the video is displayed on each video conference terminal. It disappears.

Further, the multipoint-to-point communication control apparatus is provided with an intra-frame request sending section and a filler bit sending section at the same time,
An error correction frame synchronization control unit is provided in the BCH decoding unit,
Error correction of video data By detecting the loss of frame pattern bits, it is detected in advance that erroneous video data has been delivered to the video conference terminal, and the source video conference terminal is notified of the intra-frame encoded video. In addition to the request for transmission, the filler bit is sent to freeze the video before the distorted video is displayed on each video conference terminal, and the time for repairing the displayed video is shortened.

Further, the error correction frame synchronization control unit can surely stop the transmission of the error correction frame head pulse because the synchronization is lost only when the frame pattern bits are continuously lost.

[0028]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main part of a multipoint-to-point communication control apparatus according to an embodiment of the present invention. In the figure, 4a to 4m are multiplexing units, 5a to 5m are demultiplexing units, and 6 is a video switching unit. Descriptions of components that are the same as or equivalent to those of the related art denoted by the same reference numerals in FIG. 10 are omitted. .

Reference numerals 9a to 9m denote BCH coding units for BCH coding video data to form error correction frames.
Reference symbols a to 10m are BCH decoding units that decode the BCH encoded data of the error correction frame sent from the separation units 5a to 5m and output the video data, and the configuration thereof is shown in FIG. In FIG. 7, 13 is an error correction frame synchronization control unit that detects the beginning of an error correction frame, and 14 is a BCH decoding processing unit that performs a decoding operation on the above BCH encoded data. Reference numeral 11 denotes an in-frame request transmission unit for transmitting an in-frame request according to an instruction from the system control unit 2, and 12a
Denoted at 12m is a filler bit sending unit that sets and sends the filler bit in the error correction frame.

Next, the operation will be described. Here, since the basic operation is the same as the conventional case, the description thereof will be omitted. The head of the error correction frame is found by detecting the frame pattern bit of the error correction frame shown in FIG. 8 in the error correction frame synchronization control unit 13 built in the BCH coding units 10a to 10m, and the BCH data decoding processing unit. The head pulse of the error correction frame is sent to 14. The BCH data decoding processing unit 14 recognizes the head of the BCH data from the error correction frame head pulse,
Performs decryption processing. Although error correction is possible in the BCH decoding process, if an error that exceeds the correction capability of the BCH code occurs, it becomes uncorrectable and an error correction impossible signal is sent to the system control unit 2.

The system control unit 2 receives the above-mentioned error correction impossible signal and sends the intra-frame request from the intra-frame request sending unit 11 to the video conference terminal which has sent the multiplexed data in which the error cannot be corrected. By sending an in-frame request to the video conference terminal to cause the video conference terminal to transmit the video data in the frame, the image of the receiving video conference terminal is quickly restored to a correct video.

Further, by detecting that the video data exceeds the correction capability of the BCH code, a filler bit transmission instruction is issued to the filler bit transmission units 12a to 12m to the transmission source video conference terminal, and the filler bit transmission unit 12 is sent.
Filler bits are set in a to 12 m, which means video data that is not decoded in the error correction frame. When the video conference terminal detects the filler bit, it freezes the received image and prevents the image from being disturbed by the video data that cannot be error-corrected.

The above is the means for recovering the correct image by the intra-frame request sending unit 11 and the filler bit sending unit 12.
Although an example in which the received image freeze means by a to 12m are effectively combined has been described, there are individual effects even when the in-frame request sending section 11 and the filler bit sending sections 12a to 12m are individually provided. , As shown in FIG.

Example 2. In the first embodiment, the intra-frame request and the filler bit transmission are transmitted by the error correction impossible signal. However, the frame pattern bit lost signal shown in FIGS. 4, 5, and 6 is used instead of the error correction impossible signal. However, the same effect can be obtained.

FIG. 4 is a block diagram showing a main part of a multipoint-to-point communication control apparatus according to another embodiment of the present invention. In the figure, 13 is an error correction frame synchronization control unit for detecting the beginning of the error correction frame, and FIG. 9 shows its configuration.

In FIG. 9, reference numeral 15 is a frame pattern bit detection circuit for finding a frame pattern bit, and 1
6 is a frame pattern bit loss detection circuit for detecting that there is no frame pattern bit at a predetermined position,
Reference numeral 17 is a counter that counts the number of detections and disappearances of frame pattern bits, 19 is a backward protection stage number setting circuit that determines establishment of synchronization of frame pattern bits, 20 is a forward protection stage number setting circuit that determines loss of synchronization of frame pattern bits, 18 Is a comparison circuit for comparing the number of rear protection stages and the number of front protection stages.

Next, the operation will be described. In the error correction frame synchronization control unit 13, the frame pattern bit detection circuit 15 detects the frame pattern bits from the error correction frame data, and since the frame pattern bits are regularly arranged, the position of the subsequent frame pattern bits is predicted and predicted. If there is a frame pattern bit at the position, the counter 17 is incremented.
If there is no frame pattern bit at the predicted position, this counter 17 is reset. To prevent false synchronization in error correction frame synchronization control, as the number of consecutive detections of periodic frame pattern bits to judge that synchronization establishment is established only when frame pattern bits are consecutively detected. The number of backward protection stages is set, and if the comparison circuit 18 exceeds this set value, it is determined that synchronization is established, and the error correction frame head pulse is transmitted.

Similarly, when there is no frame pattern bit at the predicted position, the frame pattern bit loss detection circuit detects it and counts up the counter 17. In this case, in order to prevent resynchronization pull-in due to the primary error of the error correction frame data, the periodic frame is used to judge that the synchronization loss is established only when the frame pattern bits are continuously lost. The number of forward protection stages is set as the number of times the pattern bits are continuously lost, and when the comparison circuit 18 exceeds this set value, the synchronization is lost and the head pulse of the error correction frame is stopped.

When the frame pattern bit loss detection circuit 16 detects the loss of the frame pattern bit, it indicates that the error correction frame data is erroneous. Therefore, this frame pattern bit loss signal is transmitted to the system control unit. By sending it to No. 2, the intra-frame request and filler bit sending operation shown in the first embodiment can be performed.

Further, as shown in FIGS. 5 and 6, the in-frame request sending unit 11 and the filler bit sending units 12a to 12a are provided.
By providing 2 m individually, each unique effect can be realized.

[0041]

As described above, according to the present invention, it is possible to quickly detect an error in video data received from a video conference terminal by sending an error-correction impossible signal or a frame pattern bit loss signal, and send erroneous video data. The in-frame request can be sent to the video conference terminal, and the disturbed video delivered to the video conference terminal can be quickly recovered.

By sending the filler bit to each video conference terminal, it is possible to freeze the video before erroneous video data is distributed and prevent the video conference terminal from displaying a disturbed video. .

Further, by combining the filler bit sending unit for freezing the image and the in-frame request for recovering the correct image, new image data can be quickly delivered without displaying the disturbed image even in a warm state. There is an effect that can be done.

Further, only when the frame pattern bit loss signal is continuously lost, the in-frame request and the filler bit sending operation are performed, and the new video data can be surely and stably delivered quickly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a multipoint-to-point communication control apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a main part of a multipoint-to-point communication control device having an in-frame request sending unit according to an embodiment of the present invention.

FIG. 3 is a block diagram showing an essential part of a multipoint-to-point communication control device having a filler bit sending unit according to an embodiment of the present invention.

FIG. 4 is a block diagram showing a main part of a multipoint communication control apparatus according to another embodiment of the present invention.

FIG. 5 is a block diagram showing a main part of an inter-multipoint communication control device having an in-frame request sending unit according to another embodiment of the present invention.

FIG. 6 is a block diagram showing a main part of a multipoint control device having a filler bit sending unit according to another embodiment of the present invention.

7 is a block diagram showing a configuration of a BCH decoding unit of the multipoint control unit of FIGS. 1, 2 and 3. FIG.

FIG. 8 is an explanatory diagram showing a transmission frame configuration of error correction frame data.

9 is a block diagram of an error correction frame synchronization control unit of the multipoint control device of FIGS. 4, 5 and 6. FIG.

FIG. 10 is a block diagram showing a conventional multipoint communication control device.

[Explanation of symbols]

 2 System control unit 4a-4m Multiplexing unit 5a-5m Separation unit 6 Video switching unit 9a-9m BCH encoding unit 10a-10m BCH decoding unit 11 In-frame request transmission unit 12a-12m Filler bit transmission unit 13 Error correction frame synchronization Control unit 14 BCH data decoding processing unit 15 Frame pattern bit detection circuit 16 Frame pattern bit loss detection circuit 17 Counter 18 Comparison circuit 19 Rear protection stage number setting circuit 20 Front protection stage number setting circuit

Claims (7)

[Claims] 1. A simultaneous multipoint television between a plurality of video conference terminals, comprising: a plurality of separation units for processing video data, audio data and general-purpose data from a plurality of video conference terminals; and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, the BC is separated by the separation unit.
Decode the BCH code of the H-encoded video data to BC
When an error in the video data that exceeds the correction capability of the H code occurs, the error correction impossible state is detected for the video data to recognize that the incorrect video data is delivered to the video conference terminal on the receiving side. Multipoint-to-multipoint, characterized by providing an intraframe request transmission unit for requesting transmission of intraframe-encoded video data to the videoconference terminal of the transmission source and restoring the video of the videoconference terminal on the receiving side to a correct video Communication control device. 2. A simultaneous multipoint television between a plurality of video conference terminals, comprising: a plurality of separation units for processing video data, audio data and general-purpose data from a plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, the BC is separated by the separation unit.
Decode the BCH code of the H-encoded video data to BC
When an error occurs in video data that exceeds the correction capability of the H code, an error correction impossible state is detected for the video data, and filler bits as video data that is not decoded are transmitted to the video conference terminal that is the sender. A multipoint communication control apparatus, characterized in that a filler bit sending section is provided to freeze the video before the disturbed video is displayed on the video conference terminal on the receiving side. 3. A simultaneous multipoint television between a plurality of video conference terminals, comprising: a plurality of separation units for processing video data, audio data and general-purpose data from a plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, the BC is separated by the separation unit.
Decode the BCH code of the H-encoded video data to BC
When an error in video data that exceeds the correction capability of the H code occurs, an error correction impossible state is detected for the video data, and filler bits as video data that is not decoded are transmitted to the video conference terminal that is the source. A filler bit sending unit is provided to freeze the video before the disturbed video is displayed on the receiving video conference terminal, and an intra-frame request sending unit to request the transmission of intra-frame encoded video data is provided. The multipoint communication control device, which restores the video of the video conference terminal of 1. to the correct video. 4. A simultaneous multipoint television between a plurality of video conference terminals, comprising: a plurality of separation units for processing video data, audio data, and general-purpose data from a plurality of video conference terminals; and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, the BC is separated by the separation unit.
When decoding the BCH code of H-coded video data, in order to detect the beginning of the BCH code, a frame pattern bit is detected from the error correction frame data generated based on a predetermined regularity, and the corresponding bit is detected. Multipoint communication characterized by including an error correction frame synchronization control unit for instructing a transmission request of intraframe coded video data to a video conference terminal of a transmission source when recognizing that a frame pattern bit is lost Control device. 5. A simultaneous multipoint TV between a plurality of video conference terminals, comprising: a plurality of separation units for processing video data, audio data, and general-purpose data from a plurality of video conference terminals; and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, the BC is separated by the separation unit.
When decoding the BCH code of H-coded video data, in order to detect the beginning of the BCH code, a frame pattern bit is detected from the error correction frame data generated based on a predetermined regularity, and the corresponding bit is detected. When it is recognized that the frame pattern bits have been lost, an error correction frame synchronization control unit is provided to instruct the transmission source video conference terminal to send out filler bits as undecoded video data. Point-to-point communication control device. 6. A simultaneous multipoint television between a plurality of video conference terminals, comprising: a plurality of separation units for processing video data, audio data and general-purpose data from a plurality of video conference terminals, and a plurality of multiplexing units. In the multipoint communication control device that realizes the conference, the BC is separated by the separation unit.
When decoding the BCH code of H-coded video data, in order to detect the beginning of the BCH code, a frame pattern bit is detected from the error correction frame data generated based on a predetermined regularity, and the corresponding bit is detected. When recognizing that the frame pattern bit has disappeared, an error that instructs the sender's video conference terminal to send out filler bits as undecoded video data and a request to send intra-frame encoded video data An inter-multipoint communication control device, characterized in that a correction frame synchronization control unit is provided. 7. The error frame synchronization control unit,
A forward protection stage number setting circuit that sets the forward protection stage number in the error correction frame synchronization control unit in order to lose synchronization only when the frame pattern bits continuously disappear,
The multipoint communication control device according to any one of claims 4 to 6, further comprising: a comparison circuit that compares the set value with the number of times of frame pattern bit loss.