KR0176632B1 - Synchronous integrated video conference control device using standard synchronization - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

Multipoint Video Conferencing System using Integrated Information and Communication Network.

2, technical problem that invention tries to solve

According to the present invention, a video conferencing control device can be integrated by using a reference synchronization without detecting FAS independently, and a frame synchronization loss of each terminal does not occur during video switching.

3. Summary of Solution to Invention

When video / audio data is exchanged between each processing unit within the video conference control device, each unit does not find synchronization and extracts video / audio data using only standard synchronization. By transferring to other units, performance is improved by not performing a separate operation for synchronization acquisition within each unit.

4. Important uses of the invention

It is used to integrate synchronous control of video, audio, and data processing units of a videoconferencing control unit as reference synchronization.

Description

Synchronous integrated video conferencing controller using reference synchronization

1 is a block diagram of a conventional videoconferencing control device.

2 is a channel data structure diagram of a comprehensive information network.

3 is a block diagram of a videoconferencing control device according to the present invention.

4 is a block diagram of a reference synchronization line according to the present invention.

5 is an input count and reference synchronization count state diagram of each channel according to the present invention.

* Explanation of symbols for main parts of the drawings

6a: ISDN BRI interface section 6c: H.221 framing section

6b: ISDN PRI interface part 6d: Data separation extracting part

6e: voice mixing unit 6f: video switching unit

6g: data processor 6h: controller

6i: Multiplexer 6j: H.221 Reframing Unit

6k: reference synchronization generator Sr: reference synchronization line

DB: Databus CB: Control Bus

The present invention relates to an apparatus for controlling video conferencing in various places using a communication network, and in particular, it is possible to integrate synchronization by generating a reference synchronization without detecting synchronization independently for each unit. It relates to a video conference control device.

Various forms of video conferencing have been developed in consideration of the rapidly developing modern industrial society. Common forms of video conferencing include point-to-point video conferencing and multi-point video conferencing in a group. Patent application No. 95-5807, filed previously by the applicant of the present application, provides a video conference control apparatus employing a comprehensive information communication network as a line interface.

FIG. 1 is a block diagram of a conventional video conferencing controller for implementing a multi-group video conferencing system. The data line connecting each part is a multi-vendor integrated protocol (MVIP). same.

The line interface units 6a and 6b perform a signal processing procedure according to ITU-T Q.931 to connect the videoconferencing control device to the ISDN network. The line interface units 6a and 6b may be configured of either BRI 6a or PRI 6b. The H.221 framing unit 6c is a module for searching and establishing the frame structure specified in H.221. When the frame alignment signal (FAS) is detected from the signal input to each channel, the H.221 framing unit 6c determines synchronization. The data separation extractor 6d extracts the image data composed of the synchronized audio, video, and data into respective independent data and delivers them on the bus. The voice mixing unit 6e includes an energy measurement unit and a mixing unit, and extracts terminals having a high acoustic energy from the sound data input from the demultiplexer 6d and mixes them. The video switching unit 6f extracts and supplies an image of a desired terminal from the image of each terminal input from the demultiplexing unit 6d. The data processor 6g processes the data input from the demultiplexer 6d. The control unit 6h controls the input / output according to the control code input from the H.221 framing unit 6c, and collectively controls the overall operation of the video conference control device by CCITT Recommendation H 230 / H.242 / H.243. Module. The data combiner 6i is a multiplexing module for recombining the data processed from the modules 6e, 6f, 6g into one data structure. The H.221 reframing unit 6j converts the data inputted from the data combination unit 6i into data having an H.221 frame structure. The converted data is then converted into the line interface unit 6a or 6b. Is transmitted through the ISDN network.

2 shows a channel data structure in an integrated telecommunication network. The data capability of an ISDN having a BRl interface is 2B (64 kbps X 2), and each B channel is composed of 8 bits.

Looking at the H.221 frame structure (ITU-T H, see Recommendation 221), if the audio is 56 Kbps, 48 Kbps, 16 Kbps, respectively, audio and video are distributed as shown in (2a), (2b) and (2c). .

On the other hand, when the terminal is connected to the video conferencing system, a time delay may occur between the B1 channel and the B2 channel, which is a case where the B1 channel connection path and the B2 channel connection path are different from each other. In this case, the B1 and B2 data input to the videoconferencing system may not be data transmitted at a certain time from the terminal. That is, when two data transmitted from the terminal are referred to as B1T1 and B2T1, the data input to the videoconferencing system may be B1T1 and B2TX.

In such a case, it is necessary to synchronize the synchronization for each channel, which must be transmitted to each data processing unit in the videoconferencing system. Since each unit receiving data has FAS and BAS in the channel, and video and audio data are mixed in the B1 channel, the FAS, which is frame sync, must be found. In other words, all units in the videoconferencing system must independently find the FAS which is H.221 frame synchronous, which is one factor that degrades the performance of the system. In addition, when video switching occurs, frame synchronization is lost, and all terminals connected to the video conference and all units in the video conference system need to acquire frame synchronization again. In other words, when video switching occurs, each terminal receives frame data synchronized with the data currently being received, and this data will be found at a new position, so synchronization loss occurs at the current position. You have to find motivation again. Therefore, if loss of synchronization occurs in all terminals during video switching, the loss of synchronization information is transmitted to the videoconferencing system, and all conference systems are temporarily lost in synchronization. Each terminal ignores the input video data until it finds synchronization again. The video is not displayed on the screen of the terminal.

Accordingly, it is an object of the present invention to provide a videoconferencing control apparatus that can synchronize with each unit by using reference synchronization without detecting FAS independently.

Another object of the present invention is to provide a video conferencing control device such that frame synchronization loss of each terminal does not occur during video switching.

The present invention for achieving the above object is to extract the video / audio data using only the reference synchronization, each unit does not find each synchronization when sending and receiving video / audio data between each processing unit in the videoconferencing control device After the process, it is configured to transfer to another unit by using the reference synchronous again.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In addition, in the following description, many specific details such as components of specific circuits are shown, which are provided to help a more general understanding of the present invention, and the present invention may be practiced without these specific details. It will be obvious to those skilled in the art, and in describing the present invention, if it is determined that the detailed description of the related well-known functions or configurations may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. .

3 is a configuration diagram of the videoconferencing control device according to the present invention, and further includes a reference synchronization generator 6k in the configuration of FIG. The reference synchronization generating unit 6k is connected to each unit of the video conference control device through the reference synchronization line Sr.

4 is a configuration diagram of a reference synchronization line according to the present invention, wherein the reference synchronization counter is incremented by 1 from φ to 159 each time a network synchronizer is input, and continues counting until 160 circular. According to this counting, if the count value is φ, a specific value (ox7e) is transmitted to a specific channel of the reference synchronous line Sr (in this embodiment, the channel φ is selected but variable), and if the count value is 159, oxe7 is drawn. All transmit φxφ (or φxFF).

If no terminal is connected to the videoconferencing control system, the data separation extracting unit 6d does not transmit any value to the audio / video / data line but transmits the value only to the reference synchronization Sr according to the above condition. On the other hand, if arbitrary terminals are connected to the videoconferencing control system, the H.221 framing unit 6C and the data separation extractor 6d acquire frame synchronization corresponding to the B1 and B2 channels of each terminal, respectively, so that the data of each terminal can be effectively used. Each data is extracted and the data is sent on the corresponding line.

The frame structure described in the Recommendation of ITU-T H.221 consists of 80 octets (bytes), each consisting of an even-frame and an odd-frame. Multi-Frame) Eight pieces are combined to form one multiframe. Since one frame has 80 octets or even and odd numbers, 160 octets are treated as a basic unit in this embodiment.

5 is an input count and reference sync count state diagram of each channel according to the present invention. In the method of synchronizing each data with the reference synchronization, first, when the frame synchronization is obtained from the data input from the network, each channel data is stored in the corresponding buffer in turn, and the size of the buffer is 160 bytes.

On the other hand, the input count of each channel represents the position where the data of the channel is currently input. The values of these counters may be different because the connection timings of the terminals are different from each other and thus the time for acquiring frame synchronization of the terminal is incorrect. However, the 69th octet of the frame is always stored at φ position of each buffer.

In order to transfer the data (stored in the buffer) synchronized in the data separation extractor 6d to each unit, the reference synchronization counter is used as an output counter. That is, when the Chxxcnts, which are input counts, have any value, they transmit the data of all channels at once using the reference synchronization count that provides reference synchronization without using these counts.

On the other hand, each unit always monitors the reference sync line, and if the value is ox7e (specific value), then it can be seen that the data entered at that time is the first octet in the H.221 frame structure. There will be no.

Therefore, each unit does not need to have a module to find frame synchronization, and after appropriately processing the data of each unit, the reference synchronization count is shot and sent to the multiplexer 6i for multiplexing the processed data. If the value is φ (i.e., when the value input to the reference sync line is a specific value), φ octets in the frame structure of the processed data are transmitted.

Since the present invention as described above uses reference synchronization, it is not necessary to have a separate module for finding frame synchronization for each unit, and it is efficient. Even when video switching occurs, H.221 relaying / multiplexing requires reference synchronization. Since all channels are synchronized using the terminal, all terminals are synchronized, and thus, even though the input data is changed, the terminal still loses frame synchronization and thus receives valid data at all times, thereby enabling smooth switching.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

Claims (5)

An apparatus for controlling videoconferencing between multiple points using a predetermined communication network, comprising: line interface means for performing a predetermined signal processing procedure for connecting to said communication network, reference synchronization generating means, and received via said communication network; Framing means for retrieving and establishing a specific frame structure of data in accordance with the reference synchronization, and composite data consisting of audio, image, and data synchronized by the framing means are extracted into each independent data in accordance with the reference synchronization, and on the bus. A data separating extraction means to be transmitted, audio mixing means for extracting and mixing the terminals having high energy from the audio data inputted from the data separating extracting means, and a desired terminal from the image of each terminal inputted from the data separating extracting means. To extract and feed images Switching means, data processing means for processing data input from the data separating and extracting means, control means for controlling input and output in accordance with a control command input from the framing means, and collectively controlling multiple video conferences; Data combining means for combining the data processed by the audio mixing means, the video switching means, and the data processing means into one complex data structure in accordance with the reference synchronization, and matching the combined data to the reference synchronization. And re-rambling means for reconverting the data having a frame structure to the line interface means. The method of claim 1, wherein the reference synchronization generating means comprises: a plurality of draft frame buffers storing each channel data, a plurality of even frame buffers storing each channel data, and a predetermined number of network synchronizing signals; And a reference synchronization counter which generates a reference synchronization having a second specific value in response to the last count value. The apparatus of claim 1, wherein the communication network is configured as a general information communication network. 3. The apparatus of claim 2, wherein the odd frame buffer and the even frame buffer are configured to pair in pairs for 32 channels. An apparatus for controlling videoconferencing between multiple points using a comprehensive information communication network, comprising: a pair of line interface means for performing a predetermined signal processing procedure for connecting to the integrated information communication network, and paired for 32 channels; A plurality of odd and even frame buffers storing each channel data, and a predetermined number of the network synchronizer signal are counted, and a reference synchronous having a second specific value corresponding to an initial count value and a first specific value corresponding to a last count value. Reference synchronization generating means comprising a reference synchronization counter for outputting to a reference synchronization line, and a framing means for retrieving and establishing a specific frame structure of data received through the integrated information communication network upon detecting the first specific value in the reference synchronization; And composite data consisting of audio, image, and data synchronized by the framing means in the reference synchronization. Data separation extracting means for extracting the first specific value into respective independent data and delivering it on a bus, audio mixing means for mixing audio data input from the data separating extracting means, and input from the data separating extracting means. Video switching means for extracting and supplying an image of a desired terminal from the images of the respective terminals, data processing means for processing data input from the data separation extracting means, and input / output control according to a control command input from the framing means. Control data for collectively controlling video conferencing of multiple groups, and data processed by the audio mixing means, the video switching means, and the data processing means, respectively, when the first specific value is detected in the reference synchronization. Data combining means for combining back into a structure; To re-convert the data into data having the first detection when the specific values of certain frame structure in the reference synchronization device, characterized by consists of reframing means for providing to the line interface means.