KR0144299B1 - Video conferencing apparatus of broadband isdn - Google Patents

Abstract

The present invention relates to a multi-party video conferencing apparatus, comprising: an ATM layer means for receiving an ATM cell containing compressed video information of a plurality of conference participants, detecting an ATM cell header, and receiving a video protocol data unit output from the ATM layer means. ATM adaptation layer means for detecting an error after analyzing the adaptation header and trailer, and compressed image information of each participant (each video sender) among compressed video information output from the ATM adaptation layer means is separately received and temporarily stored. A plurality of buffers and multiplexed compressed image information output from each of the plurality of buffers, and outputting the multiplexing means for outputting the SOP detection signal when the SOP of the compressed compressed image information is input, and the compressed image information output from the image multiplexing means Image decoding means for releasing the compressed state, compression by video decoding means A plurality of frame prediction protection means and image multiplexing means for separately receiving the frame-specific image information for each sender (for each participant) and performing frame prediction decoding by using the image information of the current frame and the image information of the previous frame. Frame memory access means and ATM layer means for controlling the decompressed frame unit image information output from the image decoding means to be input to the frame-side decoding means in a one-to-one correspondence when receiving the SOP detection signal from the apparatus. An arbitration means for distinguishing the sender of the compressed video information transmitted to the ATM cell by analyzing the ATM cell header; and if the sender of the compressed video information in the ATM cell is distinguished, the compressed video information output from the ATM adaptation layer means is distinguished for each sender. To be input to each buffer Control means for outputting the SOP detection signal from the neutralization means in order of input to each buffer, Multiple monitors for displaying the left-side decoded image information by the multiple frame prediction decoding means, respectively And monitor driving means for driving two monitors.

Description

Multiparty Video Conferencing Device of Broadband Telecommunication System

1 is a general ATM cell format diagram.

2 is a general protocol reference model diagram of a wideband asynchronous transmission mode.

3 is a detailed block diagram showing a conventional multi-party video conferencing device.

4 is a detailed block diagram showing an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

41: ATM layer 42: ATM adaptation layer

43a, 43b, 43c, 43d, 43e, 43f: buffer 44: image multiplexer

45: video decoding unit

46a, 46b, 46c, 46d, 46e, 46f, 46g: frame prediction decoder

47: frame memory connection unit 48: arbitration unit

49: control unit 50a, 50b, 50c, 50d, 50e, 50f, 50g: motor

51: monitor drive unit

The present invention relates to a multi-party video conferencing device that can efficiently decode high-speed video signals transmitted from different talkers, particularly in a broadband information communication system.

In general, Asynchronous Transfer Mode (ATM) is a communication method for implementing a Broadband Integrated Service Digital Network (BIDSN), and is a special type of packet type transfer method using Asynchronous Time Division Multiplex (ATDM).

In addition, in the BISDN, information is transmitted by a continuous flow of packets having a certain size. The fixed size packets are called ATM cells, and service information inputted as shown in FIG. (11) is divided into short cells 12 of fixed length, and then packetized by attaching a 5 byte header 12a to each cell, each ATM cell having a total of 53 bytes ( Data 48 + header 5), and each ATM cell is multiplexed and transmitted.

The ATM cell is a connectivity method, and establishes a virtual channel to deliver service information. A connection identification number is assigned whenever a virtual channel is established, and the identification number is released when the connection is released.

In addition, the order between ATM cells in a certain virtual channel is preserved by the function of the ATM layer, and signaling information for connection establishment is transmitted through a separate ATM cell.

Meanwhile, the ATM scheme defines a layered protocol model for systematic and flexible information transfer. The protocol layer envisioned at this time is a physical layer 21, an ATM layer 22, an ATM adaptation layer 23 and an upper layer 24 as shown in FIG.

In other words, ATM's protocol reference model consists of management plane (A), control plane (B), and user plane (C), and among them (A, B, C) management plane (A) functions plane management and hierarchy management. Separated by.

The one-sided management refers to the overall management of the system, the hierarchical management refers to the management of resources and usage variables, the control plane (B) manages call control and connection control information, and the user plane (C) manages the transfer of user information. do.

In addition, protocols of the control plane (B) and the user plane (C) are divided into a higher layer 24, an ATM adaptation layer 23, an ATM layer 22, a physical layer 21, and the like. Is composed of a convergence sublayer that makes user service information of the upper layer 24 into protocol data units, and a truncation and recombination sublayer that forms a user information section of an ATM cell by cutting a protocol data unit.

ATM layer 22 controls user-to-network access and information flow, translates virtual path identification numbers and virtual channel identification numbers to connect with service access points, multiplex and demultiplex cells, and physical layer 21 It consists of a transmission convergence sublayer and a physical substitute sublayer to perform separation of cell speed, generation and confirmation of header error control bytes, and detection of cell warning points. Provides functions regarding processing.

The upper layer 24 of the control plane B also provides functions for call setup, call control, and call connection, which are accomplished by exchanging control signal messages between user-networks. The control signal message may be divided into call setup, call information, call release, and additional information message according to each function.

Therefore, the transmitting ATM adaptation layer 23 receives the user service information (video, audio, data, text, drawings, etc.) from the transmitting upper layer 24 of the user plane C to perform error processing, data order preservation, and the like. A protocol data unit is created by attaching an associated header and a trailer, and transmitting the protocol data unit to the transmitting ATM layer 22, which transmits the same virtual channel among ATM cells in the data information flow. The ATM cell header 4 bytes and the header error control (HEC) 1 byte used for identifying the cells belonging to the UE are added to the transmitting physical layer 21, and the transmitting physical layer 21 transmits the ATM cell to the transmission bit string. After converting the data, the data is transmitted to the receiver through the ATM network.

The receiving physical layer 21 receives the transmission bit stream and transmits it to the receiving ATM layer 22. The receiving ATM layer 22 uses the virtual path identification number and the virtual channel identification number in the ATM cell header. By identifying the transmitting side and transmitting it to the ATM adaptation layer 23.

The ATM adaptation layer 23 receives the protocol data unit from which the ATM cell header has been removed, analyzes headers and trailers related to error processing, data order preservation, etc., and if there is no error, detects only the user service information and the upper part of the user plane C. By sending to layer 24, user service information is transmitted.

Therefore, in the related art, a video conferencing system, which is a conversation service provided between users of both ends in real time using a broadband comprehensive information communication service, has been described.

In the conventional video conferencing system, as shown in FIG. 3, an ATM cell containing compressed video information input through an ATM network 31 is detected to detect an ATM cell header, and then a virtual path identification numbering virtual channel of the ATM cell header is detected. ATM layer 32 for identifying the sender using an identification number, ATM adaptation layer for detecting error after analyzing ATM adaptation header and trailer by receiving video protocol data unit output from ATM layer 32 (33) A plurality of decoding sections 34 and a plurality of decoding sections 34, in which the transmitting side receives the same compressed video information in units of frames among the compressed video information output from the ATM adaptation layer 33, and releases the compressed state. ) Is a one-to-one correspondence, and a plurality of frame examples for performing frame prediction decoding by using the image information of the current frame and the previous frame image decompressed by the decoding unit 34. The decoder 35, the plurality of monitors 36 for displaying the image information predicted and decoded by the plurality of frame prediction decoders 35, respectively, and the monitor driver 37 for driving the plurality of monitors 36. It is configured to perform the following operations.

In general, a video conferencing system is configured such that several users conduct a meeting simultaneously.

Therefore, the ATM cell input through the ATM network 31 carries compressed video information for each video conference participant and is input to the ATM layer unit 32. The ATM layer unit 32 receives the ATM cell containing the compressed video information. After detecting the ATM cell header, the virtual path identification number and the virtual channel identification number of the ATM cell header are used to distinguish which video conference participants are currently receiving video information. Is output to the ATM adaptation stratification unit 33.

The ATM adaptation layer 33 receives an image protocol data unit thrusted by the ATM layer unit 32, analyzes an ATM adaptation header and a trailer, detects an error, and inputs the decoding unit 34 if there is no error. The unit 34 is configured to include a number of decoding units 34 corresponding to the remaining video conference attendants except the video compressed signal receiver.

That is, if there are three video conference attendants except the video compression signal receiver, the video information of the first video conference participant is input to the first decoding unit 34, and the video information of the second video conference participant is the second decoding unit. And the video information of the third video conference participant is input to the third decoding unit 34 so that video information of each conference participant, which is input to the ATM cell, is input to each decoder 34 one-to-one. To be entered correspondingly.

Therefore, each decoder 34 receives the input compressed image information in units of frames, releases the compression state, and outputs the compressed image information to each frame prediction decoder 35 connected in a one-to-one correspondence, and the frame prediction decoder 35 compresses the compression. The received image information is received, frame prediction decoding is performed, and the output is output to the monitor driver 37.

The monitor driver 36 may drive a multi-party video conference by driving the monitor 36 so that the video information of the conference attendees may be displayed when the video information is input.

However, the videoconferencing system of the related art has a decoding unit equal to the number of video conferencing participants except the video information receiver when compressed video information is loaded in an ATM cell to release the compressed state of each compressed video information separately. There was a problem in that the composition was complicated and caused a cost increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a multi-party video conferencing device capable of efficiently releasing a compressed state of compressed video information input to an ATM cell.

In order to achieve the above object, the present invention provides an ATM layer header for receiving an ATM cell containing compressed video information of a plurality of conference participants, detecting an ATM cell header, and receiving a video protocol data unit output from the ATM layer means. And ATM adaptation layer means for detecting errors after analyzing a trailer and a plurality of compressed image information of each participant (each video sender) among the compressed video information output from the ATM adaptation layer means for receiving and temporarily storing the compressed video information for each sender. A multiplexing means for multiplexing and outputting compressed image information output from a plurality of buffers, each of which outputs an SOP detection signal when a SOP of the input compressed image information is detected, and a compressed state of the compressed image information output from the image multiplexing means Video decoding means for releasing the signal, the program decompressed by the video decoding means. A plurality of frame prediction decoding means for receiving frame information separately for each sender (for each conference participant) and performing frame prediction decoding using the image information of the old frame and the image information of the previous frame, and the SOP from the image multiplexing means. Frame memory access means and ATM cell header detected by the ATM layer means for controlling the decoded frame information output from the image decoding means to be input to the frame prediction decoding means in a one-to-one correspondence to the frame prediction decoding means upon receiving the detection signal. Mediation means for distinguishing the sender of the compressed video information carried in the ATM cell by analyzing the data stream, and when the sender of the compressed video information in the ATM cell is distinguished, the compressed video information output from the ATM adaptation layer means is distinguished for each sender. Number of images multiplexed and controlled to be entered Control means for outputting the SOP detection signals from the respective buffers in order of input to each buffer, a plurality of monitors for displaying image information decoded by the plurality of frame prediction decoding means, respectively, a plurality of monitors Characterized in that it comprises a monitor driving means for driving the.

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

4 is a detailed block diagram showing an embodiment of the present invention, which is output from an ATM layer unit 41 and an ATM layer unit 41 for receiving an ATM cell containing compressed video information of each participant and detecting an ATM cell header. ATM adaptation layer unit 42 and ATM adaptation layer unit 42 that output 9 Mbps compressed video information after detecting an error by analyzing an ATM adaptation header and a trailer after receiving an image protocol data unit. Multiple buffers 43a, 43b, 43c for receiving compressed video information of each participant (each video sender) among the video information separately for each sender, temporarily storing the compressed video information, and outputting the compressed video information in frame units at a transmission rate of 1.5 Mbps. , 43d, 43e, 43f), and 1.5 Mbps compressed video information output from the plurality of buffers 43a, 43b, 43c, 43d, 43e, 43f, respectively, and 9 Mbps level output from the ATM adaptation layer unit 42. 9Mbp by multiplexing compressed video information When the SOP (Start Of Picture) of the compressed video information is outputted as s is detected, the compressed state of the 9 Mbps compressed video information output from the image multiplexer 44 and the image multiplexer 44 outputting the SOP detection signal is determined. Video information of the frame unit decompressed by the video decoding unit 45 and the video decoding unit 45 which are released is separately received for each sender (for each conference participant), so that the video information of the current frame and the video information of the previous frame are received. When the SOP detection signal is received from the plurality of frame prediction decoders 46a, 46b, 46c, 46d, 46e, 46f, and 46g, and the image multiplexer 44, the frame decoder 45 Frame memory access unit 47 for controlling the decompressed frame-based image information to be input to the frame prediction decoders 46a, 46b, 46c, 46d, 46e, 46f, and 46g in one-to-one correspondence. , ATM layer ( An arbitration unit 48 for distinguishing the sender of the compressed video information transmitted on the ATM cell by analyzing the ATM cell header detected in 41; and an ATM adaptation layer unit 42 if the sender of the compressed video information on the ATM cell is distinguished. The compressed video information outputted from the control unit is controlled to be input to each of the buffers 43a, 43b, 43c, 43d, 43e, and 43f, and each time the SOP detection signal is received from the image multiplexer 44, respectively. Of the buffers 43a, 43b, 43c, 43d, 43e, 43f, and each time the SOP detection signal is received from the image multiplexer 44, the respective buffers 43a, 43b, 43c, 43d, 43e, A plurality of frames for predicting and decoding each of the image information predicted and decoded by the control unit 49 and the plurality of frame prediction decoding units 46a, 46b, 46c, 46d, 46e, 46f, 46g, respectively, are outputted in the order inputted to 43f). Drives 50 monitors 50a, 50b, 50c, 50d, 50e, 50f, 50g, and 50 monitors 50a, 50b, 50c, 50d, 50e, 50f, 50g Consists of the monitor drive unit 51 for machine performs the following operations:

First, the ATM layer unit 41 receives an ATM cell containing compressed video information of each conference participant input through the ATM network, detects an ATM cell header included in the ATM cell, and outputs the same to the arbitration unit 48. The video protocol data unit from which the ATM cell header is removed is output to the ATM adaptation layer unit 42.

The ATM adaptation layer unit 42 detects an ATM adaptation header and a trailer of an input video protocol data unit, analyzes an ATM adaptation header and a trailer, detects an error, and outputs it at a transmission rate of 9 Mbps if there is no error.

Meanwhile, the arbitration unit 48 receives the ATM cell header separated by the ATM layer unit 41, analyzes the ATM cell header, and transmits the compressed image information transmitted in the ATM cell, that is, the current input among the plurality of conference participants. After distinguishing which sender's video information is included in the ATM cell to be output, the result is output to the controller 49, and the controller 49 controls the ATM adaptation layer 42 according to the result of the arbitration unit 48. Compressed image information output from the control unit is distinguished for each sender and inputted to each of the buffers 43a, 43b, 43c, 43d, 43e, and 43f.

That is, if the compressed video information output from the ATM adaptation layer unit 42 is the video information of the first meeting participant, it is controlled to be input to the first buffer 43a, and if the video information of the second meeting participant is the second buffer 43b. The compressed video information to the plurality of buffers 43a, 43b, 43c, 43d, 43e, and 43f in a manner of controlling the input of the compressed video information to the third buffer 43c. It is to control input by distinguishing each sender.

At this time, the transmission speed of the compressed video information output from the ATM adaptation layer unit 42 is 9Mbps, and it is provided with a total of six buffers 43a, 43b, 43c, 43d, 43e, 43f, and each buffer 43a, 43b, 43c, 43d, 43e, 43f) allows compressed video of 1.5 Mbps to be input for each sender.

The compressed image information temporarily stored in each of the buffers 43a, 43b, 43c, 43d, 43e, and 43f under the control of the controller 49 is output in the order stored in each of the buffers 43a, 43b, 43c, 43d, 43e, and 43f. When the compressed image information is input to the image multiplexer 44, the controller 49 outputs a multiplexing control signal to control the input of the image multiplexer 44.

That is, when the controller 49 outputs 000 to the image multiplexer 44, the compressed image information of the buffer 43a is input to the image multiplexer 44, and the controller 49 sends 001 to the image multiplexer 44. If output, the compressed image information of the buffer 43b is input to the image multiplexer 44, and when the controller 49 outputs 010 to the image multiplexer 44, the compressed image information of the buffer 43c is the image multiplexer 44. When the controller 49 sequentially outputs 000,001,010,011,100,101 in a manner that is input to the output, the output from the buffer 43a to the buffer 43f is sequentially input to the image multiplexer 44.

In addition, when the controller 49 outputs 110, the image multiplexer 44 receives a 9 Mbps compressed video signal output from the ATM adaptation layer 42. In this case, the compressed image information input to the image multiplexer 44 is in units of frames.

Accordingly, the image multiplexer 44 detects the SOP indicating the start of the frame after receiving the compressed image information in units of frames, and outputs the SOP detection signal to the controller 49 and the frame memory access unit 47 and then the controller 49. Each time the SOP detection signal is received, the compressed video signals are output in the order inputted to the respective buffer buffers 43a, 43b, 43c, 43d, 43e, 43f, and are input to the image multiplexer 44. .

The image decoding unit 34 releases the compressed state of the 9 Mbps compressed image information output from the image multiplexer 44 and outputs the compressed state to the frame memory connection compression image information 47, and the frame memory connection unit 47 outputs the image. Whenever the SOP detection signal is received from the multiplexer 44, the image information of the decompressed frame unit output from the image decoder 45 is distinguished for each sender, so that the frame prediction decoders 46a, 46b, 46c, 46d, 46e, 46f, 46g) to be input in a one-to-one correspondence.

The frame prediction decoder 46 receives the image information of the frame unit decompressed by the image decoder 45 separately for each sender (for each participant), and receives the image information of the current frame and the image information of the previous frame. After the frame prediction decoding is performed, the monitor driver 51 is presented to the monitor driver 51, and the monitor driver 51 controls the monitor 49 so that the image information of each participant can be displayed separately for each sender. 50b, 50c, 50d, 50e, 50f, 50g).

As described above, the present invention has an effect of efficiently decoding compressed video information of different conference participants in a multi-party video conference system.

Claims (5)

ATM layer means for receiving ATM cells containing compressed video information of multiple conference participants and detecting ATM cell headers; ATM receiving headers and trailers after receiving video SOPs from ATM layer means for detecting errors A plurality of buffers for receiving and temporarily storing compressed video information of each participant (each video sender) among the compressed video information output from the adaptation layer means and the ATM adaptation layer means for each sender, and outputting the compressed video information to each of a plurality of buffers. Image multiplexing means for multiplexing and outputting the image information, and outputting the SOP detection signal when the SOP of the input compressed image information is detected, image decoding means for releasing the compressed state of the compressed image information output from the image multiplexing means, and image decoding means. Distinguish video information in units of frames decompressed by each sender (for each conference attendee) When the SOP detection signal is received from a plurality of frame prediction decoding means and image multiplexing means for receiving frame prediction encoding by using the image information of the current frame and the image information of the previous frame, the decompression output from the image decoding means is decompressed. Frame memory access means for controlling frame-based image information to be input to the frame prediction decoding means in a one-to-one correspondence, and by analyzing the ATM cell header detected by the ATM layer means, the compressed image information is transmitted to the ATM cell. Mediation means for distinguishing the sender, when the sender of the compressed video information on the ATM cell is distinguished, the compressed video information output from the ATM adaptation layer means is controlled by the sender to be input to each buffer and the SOP detection signal from the video multiplexing means Each time you receive an input into each buffer And a plurality of monitors for respectively displaying the image information predicted and decoded by the plurality of frame prediction decoding means, and a monitor driving means for driving the plurality of monitors. Multi-party video conferencing device of broadband information communication system. The apparatus of claim 1, wherein the compressed video information output from the ATM adaptation layer means is transmitted at 9 Mbps. The apparatus of claim 1 or 2, wherein the compressed video information output from each of the plurality of buffers is transmitted at 1.5 Mbps. The multi-party video conferencing device of claim 3, wherein the plurality of buffers comprises six buffers. 4. The apparatus of claim 3, wherein the multiplexing means multiplexes and outputs compressed video information output from each of the plurality of buffers, and directly receives the compressed video information at 9 Mbps output from the ATM adaptation layer means under control of a control means. Multi-party video conferencing device of a broadband information communication system, characterized in that configured to output.