KR100327226B1 - Video phone data transfering method on IEEE 1394 & terminal structure thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video telephone data transmission method using an IEEE 1394 bus and a terminal apparatus thereof. The terminal apparatus of a video telephone system in a 1394 network connected to an IEEE 1394 network and transmitting data according to a 1394 protocol includes an image signal to be transmitted. An image processor to convert the image data into digital image data and output the transmitted image data to a predetermined screen; An audio processor converting the audio signal to be transmitted into digital audio data and outputting the transmitted audio data to the outside; A memory for storing telephone image and audio data for transmission from the image processing unit and audio processing unit, and for storing the transmitted telephone image and audio data; It allocates bandwidth and channel to transmit telephone video and audio data through 1394 bus, and transmits video and audio data through this bandwidth and channel, saves data input through 1394 bus to memory and outputs to user. A central controller; And a 1394 signal processing unit for converting data output from the central control unit into a 1394 network signal and receiving video telephone data input from the 1394 bus and outputting the video telephone data to the central control unit.

According to the present invention, video phone data is transmitted through the IEEE 1394 bus to secure a stable channel and bandwidth, thereby reducing transmission loss of image and voice data, thereby preventing deterioration in video phone communication quality.

Description

Video phone data transfering method on IEEE 1394 bus and its terminal device

The present invention relates to a video telephony system, and more particularly, to a video telephony data transmission method using an IEEE 1394 bus capable of real-time video and audio transmission while dynamically adapting to a load of a terminal on an IEEE 1394 network, and a terminal apparatus thereof. .

The IEEE 1394 serial bus (hereinafter referred to as the 1394 or 1394 bus) provides high-speed isochronous transmission based on bandwidth reservation useful for multimedia data transmission and asynchronous transmission useful for reliable command delivery. Support. 1394 is currently being developed from 100Mbps to 400Mbps and is developing hardware chips and transmission cables capable of Gbps data transmission.

Hereinafter, the characteristics of the data transfer mode supported by the 1394 bus will be described. The 1394 bus offers two transfer modes: isochronous and asynchronous. Isochronous transmission is for real-time transmission, as shown in FIG. 1, one data transmission is possible every isochronous cycle of 125 mus. On the other hand, asynchronous transmission is a mode in which data transmission is guaranteed. Transmission is controlled by a fairness interval that can be transmitted only once by all connected nodes in a section. Isochronous and asynchronous data are transferred together in an isochronous cycle, where isochronous transmission takes precedence over asynchronous transmission. However, to prevent asynchronous transmissions from being performed by priority isochronous transmissions, isochronous transmissions can only use 80% of the total cycles. That is, asynchronous transfers can use at least 20% of the cycle. If there is no isochronous transfer, the entire cycle can be used for asynchronous transfers. Isochronous transmissions and asynchronous transmissions have different characteristics in terms of information transfer as well as in bandwidth usage of isochronous cycles. Isochronous transmission uses a channel that is independent of the node's address, so data is delivered in a broadcast manner. That is, it is possible to receive isochronous data only by knowing the channel number. In contrast, asynchronous transmissions are sent with 1394 nodes and memory addresses, so only one node can transmit.

Channels and bandwidth for 1394 isochronous transmission are checked by two register-available channels (channels_available) registers and available bandwidth checks (bandwidth_available) managed by an isochronous resource manager (IRM) that is automatically elected after a bus reset. Are assigned via registers. An application that wants isochronous transfers must first be allocated channels and bandwidth in IRM using asynchronous lock transactions. Channels have numbers from 0 to 63, and if the channel of the desired number is not used, any number can be assigned regardless of the order. Since the bandwidth of the register is maintained at 1.6Gbps, the bandwidth calculated on the 200Mbps bus must be allocated by the register multiplied by eight times. When a channel and bandwidth are allocated through this process, the corresponding node can transmit data as much as the corresponding bandwidth regardless of the bus usage of other nodes using the allocated channel and bandwidth. In other words, it can be conceptually considered to use a separate physical channel having such a bandwidth.

FIG. 2 is a block diagram of a conventional video telephone system through an Ethernet LAN. In a video telephone system using an Ethernet LAN, data transmission with a specific counterpart is required, that is, a subscriber image called a user matching device 200. Referring to FIG. When video telephone data transmission is performed between devices providing a telephone service, the central control unit 201 of the user registration device 200 in which the video telephone data transmission data is generated sends a message for transmitting the generated video telephone data to another user. In order to transmit to the matching device (210, ...), it is converted into a form suitable for Ethernet LAN transmission and stored in the memory (202). The central controller 201 takes the data contained in the memory 202 and transmits the data to the Ethernet LAN 220 through the Ethernet card 203 for Ethernet communication processing. When transmitting user data, all user data is transmitted through the Ethernet LAN 220. However, when the number of users increases due to the characteristics of the Ethernet LAN and the data to be transmitted through the Ethernet LAN 220 increases, the amount of resources (bandwidth) available to each node is relatively insufficient as the number of transmissions increases on the Ethernet LAN 220. As a result of the transmission delay, there is a problem in that quality deterioration occurs in a service requiring real time transmission such as video telephone communication.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a video telephone data transmission method using a IEEE 1394 bus and a terminal apparatus capable of transmitting in real time with a minimum loss of video telephone data transmission between nodes using an IEEE 1394 bus.

1 shows an isochronous cycle of 1394.

2 is a configuration diagram of a video telephone system through a conventional Ethernet LAN.

3 is a 1394 network connection diagram for explaining the present invention.

4 is a configuration diagram of a video telephone system terminal apparatus in the IEEE 1394 network of the present invention.

5 is a configuration diagram of a video telephone system using the IEEE 1394 bus of the present invention.

FIG. 6 illustrates a process in which video phone transmission is performed between nodes forming a video phone system using the 1394 bus of FIG. 5.

7 shows an example of the format of an isochronous packet.

8 is a structure diagram of a buffer control for video phone data transmission.

In order to solve the above problems, a data transmission terminal device in a network includes an input unit for inputting a user signal; Before transmitting the user signal from the input unit, a resource for signal transmission is secured, a signal is transmitted through a resource secured by establishing a connection setup with a counterpart terminal, and a signal transmitted from the counterpart terminal through a network. A communication control unit for outputting a; And an output unit for displaying a signal from the counterpart terminal output from the controller to a user.

In order to solve the above problems, a terminal apparatus of a video telephone system in a 1394 network connected to an IEEE 1394 network and transmitting data according to a 1394 protocol converts an image signal to be transmitted into digital image data, and the transmitted image data is predetermined. An image processing unit for outputting the screen; An audio processor converting the audio signal to be transmitted into digital audio data and outputting the transmitted audio data to the outside; A memory for storing telephone image and audio data for transmission from the image processing unit and audio processing unit, and storing the transmitted telephone image and audio data; The video and audio data is transmitted through a bandwidth and channel by connecting to a node on the 1394 network and transmitting the telephone video and audio data through a 1394 bus. A central control unit for transmitting and storing video telephone data from another node on a 1394 network input through a 1394 bus in the memory and outputting the image telephone data to a user through the image processing unit and the audio processing unit; And a 1394 signal processor for converting video telephone data output from the central controller into a 1394 network signal and receiving video telephone data from another node input from the 1394 bus and outputting the telephone data to the central controller.

The central control unit,

Preferably, audio data is preferentially transmitted among the audio data and video data which are the video telephone data.

In order to solve the above problem, a node connected to an IEEE 1394 network, which receives image and audio inputs, processes them, transmits them to the 1394 bus, or outputs image and audio data (hereinafter referred to as video telephone data) transmitted from the 1394 bus. Method of transmitting video call data on the IEEE 1394 bus, the method comprising the steps of: finding a node (called node) to receive at the node (calling node) to send the video call data; Informing each of the calling node and the called node by allocating a channel and a bandwidth for transmitting video telephone data to each other; The calling node and the called node transmitting their video telephone data through the respective allocated channel and bandwidth; And upon requesting disconnection from either the calling node or the called node, resetting the bandwidth and channel and releasing the communication connection.

When transmitting the video telephone data of its own through the channel and bandwidth allocated by each node, it is preferable to transmit audio data in preference to video data.

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

Figure 3 shows a 1394 network connection diagram for explaining the present invention, each terminal (300 ~ 330) employing the 1394 protocol is connected to the 1394 bus. Here, each terminal 300 to 330 includes a camera, a microphone, an image, and an audio signal processing function so that video telephone data such as an image and a voice of a user can be generated and output between the terminals 300 to 330.

4 is a configuration diagram of a video telephone system terminal apparatus in an IEEE 1394 network according to the present invention. The video telephone system terminal apparatus in a 1394 network connected to an IEEE 1394 network and transmitting data in accordance with a 1394 protocol includes an image processing unit 400. ), An audio processor 410, a memory 420, a central controller 430, and a 1394 signal processor 440. The image processor 400 converts an image signal to be transmitted into digital image data, and outputs the transmitted image data to a predetermined screen. The audio processor 410 converts the audio signal to be transmitted into digital audio data and outputs the transmitted audio data to the outside. The memory 420 stores telephone image and audio data for transmission from the image processor 400 and the audio processor 410, and stores the transmitted telephone image and audio data. The central control unit 430 connects to a node on the 1394 network to transmit video telephone data, and allocates a bandwidth and a channel for transmitting the telephone video and audio data through a 1394 bus. The image and audio data are transmitted, and video telephone data from another node on a 1394 network input through a 1394 bus is stored in the memory 420, and then the user is transferred through the image processor 410 and the audio processor 420. Output to. The 1394 signal processor 440 converts the video telephone data output from the central controller 430 into a 1394 network signal, receives the video telephone data from another node input from the 1394 bus, and outputs the video telephone data to the central controller 430.

5 is a configuration diagram of a video telephone system using the IEEE 1394 bus according to the present invention. The video telephone system terminal serving as a node on the IEEE 1394 network includes a camera 500, an image capturing unit 510, and a video processing unit. 520, a display 530, a microphone 540, a voice processor 550, a speaker 560, a memory 570, a central controller 580, and a 1394 signal processor 590. The camera 500 captures an image such as a user image from the outside. The camera 500, the image capture unit 510, the video processor 520, and the display 530 are elements constituting the image processor 400 of FIG. 4. The microphone 540, the voice processor 550, and the speaker 560 constitute the audio processor 410 of FIG. 4. The image capture unit 510 processes the image captured by the camera 500 and converts the image into digital image data. The video processor 520 converts the image data into an image signal. The display unit 530 outputs an image that has passed through the video processor 420 such as a monitor or a screen. The microphone 540 inputs an audio signal generated by a user. The voice processor 550 converts an audio signal into digital audio data or converts digital audio data into an audio signal. The speaker 560 outputs an audio signal. The memory 570 stores image and audio data (hereinafter, referred to as video telephone data) for video telephone data transmission. The central controller 580 performs a control operation necessary for transmitting and receiving video telephone data. The 1394 signal processing unit 590 transmits the video telephone data to the 1394 bus or converts it to a 1394 network standard signal when received from the 1394 bus. Each terminal of the video telephone system using the IEEE 1394 bus has a structure as shown in FIG. 5, and signal transmission from these terminals is performed through the 1394 bus.

FIG. 6 illustrates a process in which video phone transmission is performed between nodes constituting a video phone system using the 1394 bus of FIG. 5, wherein a video phone data call unit (hereinafter referred to as A) 600 and a video phone data call unit (hereinafter, referred to as FIG. In the process of transmitting video telephone data in B) 610, first, when a telephone number to be dialed is inputted in A600, the A600 terminal internally reinterprets the node address on the 1394 network accordingly. In step 601, a signal for searching for a signal is transmitted. This signal is transmitted on a broadcast channel sent to all nodes. The B 610, which is the corresponding node to be called, interprets the signal received through the broadcast channel, recognizes that the node is called by the phone, and transmits a response signal and its node address to the A 600 (step 602). ). A 600 recognizes the node to be connected by analyzing the response signal received from B 610, and transmits a signal for requesting connection to transmit video telephone data to the node address of B 610 (step 603). ). B 610 sends a busy signal according to its state to reject a connection request or accepts a connection request. If the connection request is accepted, an isochronous channel to which an audio video signal, which is video telephone data to be received, is transmitted. (isochronous channel) and transmission bandwidth are allocated and notified to A 600, and ready to receive videophone data (step 604). When the A 600 receives the connection request permission from the B 610, it allocates an isochronous channel and a transmission bandwidth of the video phone data to be received and transmits it to the B 610, and receives the video phone data from the B 610. Prepare to do (step 605). The B 610 notifies that the isochronous channel and the transmission bandwidth have been allocated from the A 600, and transmits video telephone data generated in its own terminal (step 606). A 600 also transmits videophone data to be transmitted (step 607). When the video call data transmission is completed or the disconnection request is made at A 600 or B 610, the requesting party initializes all the information for communication, releases the channel and bandwidth, and then disconnects the connection (step 608). . In the method for transmitting video telephone data using the IEEE 1394 bus as shown in Fig. 6, the channel and bandwidth for transmitting the video telephone data are allotted in advance, so that the channel and bandwidth secured even if the amount of data transmission using the IEEE 1394 bus increases in the middle. Because of this storage, it is possible to transmit video telephone data stably regardless of the transfer amount.

Audio and video data, which are video phone data, are transmitted using 1394 isochronous channels. Audio and video data are transmitted using separate channels, and audio and video data are transmitted together in one channel. Audio and video data can be delivered together in one channel by combining audio and video data into one unit data frame and mixing audio and video data according to their frame rate. There is.

Hereinafter, as an example of calculating the size of payload (user data) included in one isochronous packet, when audio and video data are transmitted using a 1394 isochronous channel, when mixed and transmitted according to a frame rate, 16 The size of a QCIF image with bit color pixels is 176x144x2 (16) = 50,688 bytes, assuming that the video and audio data are transmitted 30 frames per second. / 30 = 266 packet transmissions should be made. Since 50688 bytes must be transmitted in 266 packet storages, 50688/266 = 191 bytes per packet must be able to be transmitted. However, since the 1394 packet is processed in units of four bytes of quadlets, the payload of the packet is 192 bytes.

7 shows an example of the format of an isochronous packet. When calculating the bandwidth for video telephony data transmission, the four quadlet packet overhead representing the packet header and error correction code (CRC), and the 1394 bus arbitration and signaling It must be allocated with a bus overhead.

8 is a structure diagram of a buffer control for video phone data transmission. Video telephony must deliver video and audio data simultaneously. Both video and audio data require real-time delivery, but have different characteristics: While audio data causes a problem that seriously degrades the call experience felt by the user when partial loss or omission occurs, video data has temporal redundancy, so even if the number of frames displayed per second decreases. It is not sensitive. For this reason, the terminals for video telephone data transmission in FIG. 3 preferentially process audio data in order to prevent loss or loss of audio among video data and audio data transmitted through one 1394 channel. That is, irregular delays occurring in the system are absorbed by missing video frames. In addition, since the audio signal has a smaller data size and a smaller processing load in the system than the video signal, the received data can be directly processed in hardware without a separate buffering process. In the buffer control structure for video phone data transmission of FIG. 8, each transmission / reception buffer operation is performed through the C terminal 800 which sends the video telephone data and the D terminal 810 which receives the video telephone data from the C terminal 800. FIG. Explain. First, in the C terminal 800, the generated video data frame is stored in the vframe 801, which indicates whether the sbuf 802, which is a buffer for transmitting data to the 1394 bus, is resting or storing other data (busy). If the status flag fs is checked and idle, the video frame is moved to sbuf 802 and sent to the 1394 bus. If the status flag fs is busy, it is determined that transmission of the data currently included in the sbuf 802 is not completed, and it is determined that other data has occurred in the C terminal 800, and discards the video data frame. The audio data generated by the C terminal 800 is stored in the ablock 803. If the status flag of the sbuf 802 is checked as the video data and the sbuf 802 is idle, the audio data is sbuf 802. ) So that audio data is sent to the 1394 bus. When the status flag is busy, the processing of audio data, unlike the case of the above video data, places and stores a buffer called asbuf 804 in order to ensure the continuity of the output. After completing the incomplete data transmission, the sbuf 802 checks the asbuf 804 first and, if there is audio data, fetches and transmits the audio data. In this way, audio data is processed preferentially over video data, so video data can only be transmitted when there is no audio data or when no data is being sent on the 1394 bus.

In the process of receiving the data sent by the C terminal 800 from the D terminal 810, first, when the video telephone data transmitted from the 1394 bus is received by the rbuf 811, it is determined whether the received data is video data or audio data. In the case of video data, the screen state flag fv indicating the display state of the screen is examined, and if it is busy, it is put into vrbuf 812 and fvr, which is a flag indicating the state of the buffer, is set. If the display state is not busy, the data in vrbuf 812 is displayed. At this time, if the received data of 1394 performed in parallel arrives before the data in the vrbuf 812 is displayed, the fvr is checked and discarded. The buffer control operation so far in the D terminal 810 corresponds to a case where the received data is video data. If the data input to the D terminal 810 through the 1394 bus is audio data, a separate buffer control operation is not required. The audio signal is processed immediately and output to the speaker 813 without sound.

In the video telephone system of the present invention, in addition to the video telephone signal (audio and video signal) transmission function, it is possible to provide a chatting function and a file transfer function. Text and file transfers for chat also take place via the 1394 bus.

According to the present invention, by transmitting video phone data through the IEEE 1394 bus to secure a stable channel and bandwidth, the transmission loss of image and voice data can be lowered to prevent deterioration of video phone communication quality. By prioritizing, user service quality can be increased.

Claims (6)

A video telephone system terminal in a 1394 network connected to an IEEE 1394 network and transmitting data according to a 1394 protocol, An image processor which converts an image signal to be transmitted into digital image data and outputs the transmitted image data to a predetermined screen; An audio processor converting the audio signal to be transmitted into digital audio data and outputting the transmitted audio data to the outside; A memory for storing telephone image and audio data for transmission from the image processing unit and audio processing unit, and storing the transmitted telephone image and audio data; The video and audio data is transmitted through a bandwidth and channel by connecting to a node on the 1394 network and transmitting the telephone video and audio data through a 1394 bus. A central control unit for transmitting and storing video telephone data from another node on a 1394 network input through a 1394 bus in the memory and outputting the image telephone data to a user through the image processing unit and the audio processing unit; An IEEE1394 bus, comprising: a 1394 signal processor for converting video telephone data output from the central controller into a 1394 network signal and receiving video telephone data from another node input from the 1394 bus and outputting the video telephone data to the central controller; Video telephone system terminal using the. The video call data of claim 1, wherein A video telephone system terminal using the IEEE 1394 bus, characterized in that it further comprises text data for chatting. The video call data of claim 1, wherein An image telephone system terminal apparatus using the IEEE 1394 bus, characterized by further comprising file transfer data. The method of claim 1, wherein the central control unit, An audio telephone system terminal apparatus using the IEEE 1394 bus, characterized in that audio data is first transmitted among audio data and video data which are the video telephone data. Images on the IEEE 1394 bus of nodes connected on an IEEE 1394 network, receiving and processing image and audio input and transmitting to the 1394 bus or outputting image and audio data (hereinafter referred to as video telephone data) transmitted from the 1394 bus. In the telephone data transmission method, Making a connection request by finding a node (hereinafter referred to as a called node) to be received by a node (hereinafter called call node) to which the video telephone data is to be sent; Informing each of the calling node and the called node by allocating a channel and a bandwidth for transmitting video telephone data to each other; The calling node and the called node transmitting their video telephone data through the respective allocated channel and bandwidth; And Resetting the bandwidth and the channel and releasing the communication connection if either of the calling node or the called node requests a disconnection. The method of claim 5, And transmitting audio video data in preference to video data when transmitting the video telephone data of each node through the allocated channel and bandwidth of each node.