KR100197861B1 - Apparatus for changing group number in a video conference system - Google Patents

Abstract

The present invention consists of one video header and three block group data in a video conferencing system, each of the first and second blocks consisting of a block group start code, a block number, and macro block data. A device for changing a block number in block group data for integrating 3,4 picture data (QCIF) into a fifth picture data (CIF) consisting of one picture header and 12 block group data. When a picture header of the first picture data is detected among the first, second, third, and fourth picture data, a picture header detection signal and a detected picture header are output, and the picture header detected in the remaining picture data is removed to remove the first picture data. An image input control unit 10 for outputting block group data of 2,3,4 image data; A counter 20 reset by an image header detection signal from the image input control unit 10 and counted up by a block group start detection signal; A converter 30 for converting the count value from the counter 20 into serial data and outputting the serial data; First, second, and second to selectively store the block group data of the first, second, third and fourth image data applied from the image input control unit and output the stored block group data based on a second selection signal; 3,4 first-in, first-out memory (41, 42, 43, 44); A first selection unit (50) for outputting a first selection signal for selection of the first, second, third, and fourth-in first-out memories based on the count value from the conversion unit (30); A second selection unit (60) for outputting the second selection signal for selection of the first, second, third and fourth first-in first-out memories (41, 42, 43, 44) based on the first selection signal; A first multiplexer section (70) for selectively outputting block group data from said first, second, third and fourth first-in first-out memories (41, 42, 43, 44) based on said first selection signal; Block group start detection unit 80 which detects a block group start code from the block group data output from the first, second, third and fourth first-in first-out memories 41, 42, 43, 44 and outputs the block group start detection signal. )Wow; A third selector (90) for outputting a third select signal based on the block group start detection signal; The output signal of the first multiplexer unit 70 and the output signal from the conversion unit 30 are selectively output based on the third selection signal and applied from the first multiplexer unit 70. The fifth, in which the first, second, third and fourth picture data (QCIF) are composed of one picture header and twelve block group data by replacing the block number in the block group data with the output of the conversion section 30; And a second multiplexer unit 100 which integrates and outputs the image data CIF.

Description

Device for changing group number in video conferencing system

1 is a block diagram of an apparatus for changing a group number according to the present invention.

2 shows a data format in a video conferencing system.

* Explanation of symbols for main parts of the drawings

10: image input control unit 20: counter

30: converter

41, 42, 43, 44: First, First, First, First, First, First-Out Memory

50, 60, 90: 1, 2, 3, selector 70, 100: 1, 2 multiplexer

80: block group start detector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video conferencing system. In particular, a group number of data structures in a process of integrating a plurality of (four) compressed video data into one video data for multi-party conferencing in a video conferencing system. And a group number changing device in a video conference system.

In general, a video conferencing system is a system that transmits video, audio, and telematic data between distant users so that a user can conduct a meeting as if they were in the same meeting place.

This video conferencing system is an economical system capable of exchanging information and making decisions depending on the situation in corporate activities. The system is currently being developed by several companies around the world, and some products have already been commercialized.

Meanwhile, in order to enable multi-party video conferencing in a video conferencing system, a high performance multi-point control unit (MCU) with powerful functions is essential. In order to facilitate a multi-party meeting without using an MCU, video, audio, and telematics data from the conference participants must be delivered to everyone, which requires as many video / audio codecs as there are participants.

In the case of audio, the number of codecs can be reduced using a mixing method, but in the case of video, mixing is impossible due to the characteristics of an image.

Therefore, in order to conduct a multi-party conference simultaneously with one video codec, a method of receiving compressed video information (QCIF) for each conference participant (four people) and integrating it into one compressed picture information (CIF) Should be.

First, a data structure of a video conference system will be described with reference to FIG. 2 in order to integrate compressed information into image information.

The videoconferencing system follows CCITT Recommendation H. 261 and therefore operates on Non-Interlaced Pictuere, which occurs approximately 29.97 times per second. The image is encoded with one luminance (Y) and two color difference components (Cb, Cr). H. 261 compatible formats include Common Intermediate Format (CIF) and Quarter CIF (QCIF).

The video resolution in CIF is set to 352 pixels x 288 lines, and in QCIF 176 pixels x 144 lines. The data structure of the video coding algorithm recommended by CCITT is based on the Picture layer and the Groups Of Blocks (GOBs). It is organized in stages such as hierarchy, macro blocks hierarchy, and blocks hierarchy.

The beginning of each layer is determined by its header. The picture header is a picture start code (PSC: Picture Start Code) having a value of 0000 0000 0000 0001 0000, and the block group header is a block group start code (GBSC: Groups Of Blocks Start Code) having a value of 0000 0000 0000 0001. Is recognized by

The format of the picture layer has four QCIFs as CIFs. That is, CIF consists of 12 block groups and QCIF consists of 3 block groups.

Each block group has a 4-bit group number at a position after the block group start code in the header of the block group and a 5-bit group quantization information at the next position. Thus, to conduct a multi-party video conferencing with one video codec, each participant's picture (picture transmitted in QCIF is transmitted) must be integrated into one CIF.

At this time, the necessity of changing and integrating the group number in the block group of each QCIF into the group number corresponding to the CIF arises.

Accordingly, an object of the present invention is to change the group number of each QCIF according to CIF and to integrate it into CIF when four QCIFs are integrated into one CIF in the video conferencing system. It is to provide a change device.

The apparatus for changing a group number in a video conferencing system according to the present invention comprises one video header and three block group data in the video conferencing system, wherein the block group data includes a block group start code, a block number, and a macro. In the block group data for incorporating each of the first, second, third and fourth picture data (QCIF) composed of block data into a fifth picture data (CIF) composed of one picture header and 12 block group data. A block number changing device, wherein when a picture header of the first picture data is detected among sequentially inputted first, second, third, and fourth picture data, a picture header detection signal and a detected picture header are outputted, and the remaining picture data is output. An image input control unit (10) which removes the detected image header and outputs block group data of the first, second, third and fourth image data; A counter 20 reset by an image header detection signal from the image input control unit and counted up by a block group start detection signal; A converter (30) for converting the count value from the counter into serial data and outputting the serial data; First and second blocks for storing block group data of the first, second, third and fourth image data applied from the image input control unit, and selectively outputting the block group data stored and output enabled based on the second selection signal. 3, 4 first-in, first-out memory (41, 42, 43, 44); A first selection unit (50) for outputting a first selection signal for selecting the first, second, third, and fourth pre-emption memories based on the count (20) value from the conversion unit; A second selection unit (60) for outputting the second selection signal for selecting the first, second, third, fourth, first-in, first-out memory based on the first selection signal; A first multiplexer section (70) for selectively outputting block group data from said first, second, third and fourth first-in first-out memories based on said first selection signal; A block group start detection unit (80) for detecting a block group start code from the block group data output from the first, second, third, and fourth first-in, first-out memory and outputting the block group start detection signal; A third selector (90) for outputting a third select signal based on the block group start detection signal; The block group data applied from the first multiplexer unit by selectively outputting the output signal of the first multiplexer unit 70 and the output signal from the converter unit 30 based on the third selection signal. The fifth image data (CIF) in which the first, second, third and fourth image data (QCIF) are composed of one image header and twelve block group data, by substituting the block number in the field with the output of the counter 20. And a second multiplexer unit integrated into the output unit.

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

1 is a block diagram of an apparatus for changing a group number according to the present invention, wherein the image input control unit 10, the counter 20, the conversion unit 30, and the first, second, third and fourth first-in first-out memories 41 and 42 are shown. 43, 44, the first selector 50, the second selector 60, the first multiplexer 70, the block group start detector 80, the third selector 90, and the second multi The flexure unit 100 is included.

In the figure, the image input control unit 10 detects the image header of the first image data from among the first, second, third, and fourth image data QCIF inputted by carrying images of each video conference participant. The detection signal and the detected picture header are output, and the picture header detected from the remaining picture data (second, third and fourth picture data) is removed to output block group data of the first, second, third and fourth picture data.

The counter 20 is reset to '0' based on the image header detection signal from the image input control unit 10 and counted up based on the block group start detection signal described later to output a count value.

In addition, the converter 30 converts the parallel count value from the counter 20 into a serial count value and outputs it.

Meanwhile, the first, second, third and fourth first-in first-out memories 41, 42, 43 and 44 respectively store block group data of the first, second, third and fourth image data applied from the image input control unit 10. And selectively outputting block group data which is output enabled and stored according to the second selection signal.

The first selector 50 supplies a first selection signal for selecting the first, second, third and fourth first-in first-out memories 41, 42, 43, and 44 based on the count value from the counter 20. Output

In detail, the first selector 50 alternately selects the first and second first-in first-out memories 41 and 42 three times each time the counter 20 is up, and then, when the counter 20 is up. Each time the third and fourth first-in first-out memories 43 and 44 are alternately outputted, a first selection signal for selecting three times is also output.

In addition, the second selector 60 checks the outputs of the first, second, third, and fourth first-in, first-out memories 41, 42, 43, and 44 based on the first select signal from the first selector 50. Output a second select signal for enabling.

On the other hand, the first multiplexer section 70 blocks from the first, second, third and fourth first-in first-out memories 41, 42, 43, 44 based on the first selection signal from the first selector 60. Output group data selectively.

The block group start detection unit 80 detects the block group start code from the block group data output from the first, second, third, and fourth first-in first-out memories, and outputs a block group start detection signal.

Further, the third selector 90 outputs a third select signal based on the block group start detection signal from the block group start detection unit 80.

In other words, the block group data is composed of a block start code, a block number, and a macro block data. Therefore, the block group data is set to the value of the counter 20 that is linearly counted up to change the block number corresponding to the QCIF according to the CIF. In order to replace, a third selection signal for changing and outputting a predetermined bit (4 bits) of the block number to the counter 20 value is outputted.

On the other hand, the second multiplexer section 100 is in series with the block group data from the first multiplexer section 70 and the conversion section 30 based on the third selection signal from the third selector 90. Optionally output the changed group number, which is the converted 4-bit count value, and integrate the first, second, third, and fourth picture data (QCIF) into the sixth picture data (CIF) composed of one picture header and 12 block group data. To print.

Next, an operation process of the group number changing apparatus in the image system according to the present invention including the above-described configuration unit will be described in detail.

First, four video conference participant images are sequentially applied to the image input control unit 10 in the above-described QCIF data format (resolution: 176 pixels x 144 lines).

Then, the image input control unit 10 detects the first image header from each of the inputted first, second, third, and fourth image data, and outputs the image header detection signal to the counter 20. 41) outputs the block group data including the image header as it is, and removes the image header from the remaining second, third and fourth image data and outputs it to the second, third and fourth first-in first-out memories 42, 43 and 44, respectively. .

In detail, the first-in first-out memory 41 has a block group start code and a group number of the picture header of the first picture data, the three block group data of the first picture data, and the first block group data of the second picture data. Stored.

The second first-in first-out memory 42 is a block group start code of three block group data excluding the block group start code of the first block group data and the group number from the second image data and the first block group data of the third image data. And group number is stored.

Further, the third first-in first-out memory 43 is a block group start code of three block group data excluding the block group start code of the first block group data and the group number from the third image data and the first block group data of the fourth image data. And group number is stored.

On the other hand, the fourth first-in-first-out memory 44 stores three block group data except for the block group start code and the group number of the first block group data of the fourth image data.

Next, the counter 20 which has received the image header detection signal from the image input control unit 10 is reset to the initial value '0'.

Then, the first selector 50 selects the first, second, third, fourth first-in first-out memories 41, 42, 43, 44 based on the count value from the counter 20. The first selection signal is output, and the second selection unit 60 is based on the first selection signal from the first selection unit 50. A second select signal for selectively outputting 44) is output.

At this time, when the value of the counter 20 is "0", the block group data including the image header stored in the first-in, first-out memory 41 is output enabled and output.

The first multiplexer section 70 selects and outputs the image header and block data from the first-in first-out memory 41 based on the first select signal from the first selector 50.

At this time, the block group start detection unit 80 detects the block group start code from the output data from the first-in, first-out, memory 41 and, when the block group start code is detected, transmits a predetermined block group start detection signal to the counter 20. Output to the third selector 90.

Therefore, when the first block group start code is detected by the block group start detection unit 80, the counter 20 is counted up based on the applied block group start detection signal to have a value of '1'.

Then, the third selector 100 is a group number of a predetermined bit (4 bits) following the block group start code of the block group data applied from the first multiplexer unit 70 based on the applied block group start detection signal. Is replaced by a value that is converted from serial data into the serial data and outputted by the converter 30, and the group number is changed to match the CIF data format.

Next, when the block group start code is detected by the block group start detection unit 80 in the next block group data from the first-in, first-out memory 41, the counter 20 counts up to '2' by the above-described procedure. The second first-in first-out memory 42 is output enabled, and the first multiplexer unit 70 selects and outputs the second first-in first-out memory 42.

Therefore, when the first block group data of the second image data is selected and outputted, the second block group data of the first image data is selected and output again next time.

As described above, the block group data of the first image data and the second image data are selected alternately so that the group number is changed and output, and the block group data of the third image data and the fourth image data are alternately selected. Thus, the group number is changed and output to output a bit stream of one QCIF data format.

As described above, according to the present invention, the image data of one CIF format is changed by changing the group number in the four image data into four group data corresponding to one CIF format with four image data inputted in the CIF format in the video conference system. It is effective to integrate into.

Claims (1)

In the video conferencing system, one picture header and three block group data are included, and each block group data includes a block group start code, a block number, and macro block data. An apparatus for changing a group number in block group data for incorporating picture data (QCIF) into a fifth picture data (CIF) consisting of one picture header and 12 block group data, the first input sequentially When the image header of the first image data is detected among the 2, 3, and 4 image data, the image header detection signal and the detected image header are output, and the image header detected from the remaining image data is removed to remove the first, second, and third image data. An image input control unit 10 for outputting block group data of 3,4 image data; A counter 20 reset by an image header detection signal from the image input control unit 10 and counted up by a block group start detection signal; A converter 30 for converting the count value from the counter 20 into serial data and outputting the serial data; A first block for storing block group data of the first, second, third and fourth image data applied from the image input control unit 10 and selectively outputting the block group data that is output enabled based on a second selection signal; 2, 3, 4 first-in, first-out memory (41, 42, 43, 44); A first selection unit (50) for outputting a first selection signal for selection of the first, second, third, and fourth-in first-out memories based on the count value from the counter (20); A second selection unit (60) for outputting the second selection signal for selection of the first, second, third and fourth first-in first-out memories (41, 42, 43, 44) based on the first selection signal; A first multiplexer section (70) for selectively outputting block group data from said first, second, third and fourth first-in first-out memories (41, 42, 43, 44) based on said first selection signal; A group start detector 80 which detects a block group start code from the block group data output from the first, second, third, fourth first-in first-out memories 41, 42, 43, and 44 and outputs the block block group start detection signal; )Wow; A third selector (90) for outputting a third select signal based on the block group start detection signal; The output signal of the first multiplexer unit 70 and the output signal from the conversion unit 30 are selectively output based on the third selection signal, and applied from the first multiplexer unit 70. The fifth, in which the first, second, third and fourth picture data (QCIF) are composed of one picture header and twelve block group data by replacing the block number in the block group data with the output of the conversion section 30; And a second multiplexer unit (100) which integrates and outputs the image data (CIF).