KR20060057823A - Mac controller for high speed multimedia streaming and method of the same - Google Patents

Abstract

An apparatus and method for controlling MAC for high speed multimedia streaming is disclosed. The network connection unit is connected to a physical network to transmit and receive data with a server providing multimedia data via Ethernet. The filtering control unit determines whether or not to sort the frame introduced through the network connection unit, and determines a parameter used for the filtering process for the frame. When the screening process for the frame is determined by the filtering controller, the filtering engine selects and outputs the screening target frame based on the parameter from the frames flowing through the network connection unit. The buffer stores the high-speed large-capacity sorting processing frame input from the filtering engine. According to the present invention, it is possible to prevent the degradation of the performance of the entire embedded system by reserving the resources of the main CPU, and to improve the performance of the overall system by reducing the data transfer bandwidth between the main CPU and peripheral devices.

Ethernet, Frame, Screening, TCP / IP, MAC

Description

MAC controller for High speed multimedia streaming and method of the same}

1 is a diagram illustrating a general example of various media content services using a network;

2 illustrates general protocols used for transmitting media data over a network;

3 illustrates a detailed configuration of a terminal;

4A and 4B show different system configurations according to the AV data processing method;

5 is a block diagram showing a detailed configuration of an apparatus for controlling MAC for high speed multimedia streaming according to the present invention;

6 is a diagram illustrating a structure of an IP packet transmitted through Ethernet;

7 is a block diagram showing a detailed configuration of a filtering engine;

8 is a diagram showing a detailed configuration of an error detection unit, and

9 is a flowchart illustrating a process of performing a MAC control method for high speed multimedia streaming according to the present invention.

The present invention relates to a MAC control apparatus and method for high-speed multimedia streaming, and more particularly, to a MAC control apparatus for high-speed multimedia streaming to prevent the degradation of the overall system performance that occurs when processing high-speed / large capacity network data and It is about a method.

With the rapid spread of high-speed data networks, multimedia data processing that requires real-time processing of large-capacity, high-quality network data, especially moving picture data including MPEG (Moving Picture Experts Group), MP3 / WMA audio data, and 3D-based graphic data In an environment where there is an increasing demand for services, an embedded system that supports high-speed data processing and a variety of multimedia codecs (CODECs, COder-DECoder) can be used for back-bone network topology. topology), the transmission method in the subscriber terminal and the content become important components.

1 is a diagram illustrating a general example of various media content services using a network.

Referring to FIG. 1, a network includes servers 110 providing various types of content, a network topology and a subscriber access device 120, and various types of terminals 130.

The servers 110 accommodate contents for serving various types of media data, which are not only text or binary data but also compressed still images, moving images, voice, music and animations, and 2D /. It contains 3D graphics and uses different transmission protocols depending on the characteristics of each data.

The network topology and the subscriber access device 120 can be configured in various ways according to the transmission equipment and protocol used as a network configuration method between the server and the terminal or the connection device to which the terminal is connected, but data transmitted between the server and the application of the terminal. It seems transparent by not manipulating it. The most important consideration in the topology construction is the quality of the transmission service, such as bandwidth and loss rate required for data transmission between the server and the terminal. The network is divided into main network managed by the service provider and the subscriber access network in the subscriber's home. In the case of the subscriber network, ADSL or VDSL capable of high-speed data transmission is mainstream.

The terminal 130 refers to all types of end service devices used by subscribers, and is connected to a network in order to receive a service through the network. The main basic function configuration of the terminal is the function of accessing the network and carrying out the transmission protocol, restoring the multimedia data received from the server, especially compressed AV (Audio Video) data, and playing back and displaying the restored data, It consists of a function to receive a command. The execution of these functions can be performed in hardware or software except for the physical parts.

2 is a diagram illustrating general protocols used for transmitting media data over a network.

Referring to FIG. 2, the servers are compressed based on the real-time streaming protocol described in the Web server, the FTP file server, and the RFC, which support text, graphic, and image data using the TCP protocol according to the provided content and usage protocol. RTSP / RTP streaming server that controls and transmits the moving picture or music data in the conventional form, VoD server using the general UDP protocol, and the latest Internet radio and music broadcasting server. These various types and functions of servers may be physically implemented as one system or multiple systems.

3 is a diagram illustrating a detailed configuration of a terminal. The function of the block represented by a dotted line in FIG. 3 is a part that can be performed by software or dedicated hardware according to the performance of the main CPU. 4A and 4B are diagrams showing a system configuration according to the AV data processing method. FIG. 4A shows a system in which the main CPU processes all transmission data including multimedia data in software, and FIG. 4B shows a system designed to process AV data in AV dedicated hardware.

In order to perform such a function, the terminal requires a main CPU, memory, and MAC controller, commonly called a network interface card (NIC), to access a network. As described above, the AV data can be processed in CODEC-only hardware or in the main CPU.

In this network-based multimedia countermeasure system, high-speed network data congestion causes frequent interruption or polling that requires data transfer from the buffer inside the MAC controller to the system memory, which is indicated by dotted lines in FIGS. 4A and 4B. The excessive performance of the data transfer bandwidth between the main CPU and the peripheral device shown affects the performance of the entire system and the resource allocation cycle of the operating system, which prevents the smooth performance of other necessary functions. To solve this problem, high-performance and expensive main CPUs are used to solve these problems. Especially, in order to meet the multimedia data demands of users who are familiar with the functions and environment of the desktop PC, almost a desktop PC-class hardware platform is needed. In fact, most of the consumer Internet access devices are equipped with PC hardware and operating system, and the increase in price is a major limiting factor in the expansion of the embedded multimedia terminal based on the network.

On the other hand, among the components shown in FIG. 1, among the devices used as the terminal 130, the desktop PC has an advantageous aspect of user friendliness in performance and use environment, but VOD (Video On Demand), broadcasting viewing, and music file There are limitations in terms of isolation from space using entertainment services such as regeneration, high price, and differences from existing powerful user interfaces such as TV and remote control. Therefore, some development / production companies are launching set-top boxes in the form of white consumer electronics with a built-in PC, which solves only the user interface problem but is still not free in price.

As a result, almost all desktop PC-class hardware platforms are needed to meet the multimedia data needs of users who are familiar with the functions and environment of desktop PCs. In most cases, there is a problem that the increase in price is an important limiting factor for expansion of supply.

The technical problem to be achieved by the present invention is to reduce the burden of excessive network data processing on the main CPU by selecting and transmitting multimedia data required for real-time processing in the MAC controller, while real-time processing data is separated from the bus. The present invention provides a MAC control apparatus and method for high-speed multimedia streaming that prevents a specific peripheral device such as a MAC controller from exclusively occupying the system data bus, thereby preventing overall system performance degradation.

In order to achieve the above technical problem, the MAC control apparatus for high-speed multimedia streaming according to the present invention, the network connection unit for transmitting and receiving data to and from a server providing multimedia data via Ethernet connected to a physical network; A filtering control unit which determines whether or not to sort the frame introduced through the network connection unit and determines a parameter used for the sorting process for the frame; A filtering engine for selecting and outputting a screening target frame based on the parameter from among frames introduced through the network connection unit when the screening process for the frame is determined by the filtering controller; And a buffer for storing a high-speed large-capacity sorting processing frame input from the filtering engine.

In order to achieve the above technical problem, the MAC control method for high-speed multimedia streaming according to the present invention, (a) whether or not the screening process for the frame flowing from the server for providing multimedia data over Ethernet and the screening for the frame Determining a parameter used for processing; (b) if the screening process for the frame is determined, selecting and outputting a high speed and large capacity screening target frame based on the parameter from the frames flowing from the server; And (c) storing the screening target frame in a buffer.

As a result, deterioration of the performance of the entire embedded system can be prevented by reserving the resources of the main CPU, and the overall system performance can be expected by reducing the data transfer bandwidth between the main CPU and the peripheral device.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the MAC control apparatus and method for high-speed multimedia streaming according to the present invention.

5 is a block diagram illustrating a detailed configuration of an apparatus for controlling MAC for high speed multimedia streaming according to the present invention.

Referring to FIG. 5, the MAC control apparatus 500 for high-speed multimedia streaming according to the present invention includes a network connection unit 510, a filtering control unit 520, a filtering engine 530, a buffer 540, and a CPU interface unit ( 550 and an error detection unit 560.

The network connection unit 510 is connected to a physical network and transmits and receives data with a server providing multimedia data through Ethernet.

The filtering control unit 520 determines whether or not to sort the frame introduced through the network connection unit 510, and determines a parameter used for the sorting process for the frame. The parameter is selected from at least one of a protocol type, an IP port number, a protocol number, and a MAC address, and used individually or in combination to determine whether to process a frame. On the other hand, in the case where the parameters are used in combination, the application order of the plurality of parameters is set in advance, and is used to determine whether or not to process the frame sequentially in accordance with the set application order. 6 illustrates a structure of an IP packet transmitted through Ethernet, and dotted lines of the fields constituting the packet structure illustrated in FIG. 6 are used as filtering parameters in the filtering engine 530.

When the filtering process 530 determines the screening process for the frame by the filtering control unit 520, the filtering engine 530 selects and outputs the screening target frame based on a parameter set in advance among the frames flowing through the network connection unit 510. do. The selection control function of the filtering engine 530 is controlled by the main CPU through the CPU interface 550. On the other hand, the interface bus 550 reduces the transmission bandwidth between the buffer 540 and the main CPU that reads out and processes the selection target frame stored in the buffer 540.

7 is a block diagram showing a detailed configuration of a filtering engine.

Referring to FIG. 7, the filtering engine 530 includes an input data coefficient unit 532, a parameter storage unit 534, a comparison unit 536, and a demultiplexer 538.

The input data counting unit 532 combines and counts the frame data in the form of a serial bit stream flowing through the network connection unit 510 in units of bytes and positions the fields in which the parameter values used for screening are selected among the fields constituting the frame. Specifies. The parameter storage unit 534 stores at least one parameter used for the screening process determined by the filtering control unit 510. The comparator 536 is a field value recorded in a field designated by the input data counting unit 532 among the fields constituting the frame flowing through the network connection unit 510 and a parameter stored in the parameter storage unit 534. If the values match, the frame flowing through the network connection unit 510 is determined as the selection target frame. The demultiplexer 538 outputs, to the buffer 550, a frame determined by the comparator 538 among the frames flowing through the network connection unit 510 to be a selection target frame.

The buffer 540 stores a high-speed large-capacity sorting processing frame input from the filtering engine 530. The buffer 540 is a circular buffer that stores a frame under the control of the demultiplexer 240 constituting the filtering engine 530 described later. In general, transmission of Ethernet packets based on Transmission Control Protocol / Internet Protocol (TCP / IP) makes it difficult to predict the concentration of network data by sharing transmission media, which is delay or loss of multimedia data that must be prioritized in real time. This can affect the quality of the entire service, but buffering is essential to prevent this, but more buffering than necessary takes up a lot of data storage space, leading to price increases and transmission time delays. It is determined in consideration of the maximum transmission rate of the multimedia data to be processed and the network concentration.The preferred buffer 540 has a size that can store about 100 to 150 frames of MPEG2 transport stream packets, and the buffer 540 Uniform standing by absorbing and averaging the instantaneous transfer rate changes It is possible to maintain the quality of the scan.

The error detector 560 is stored in the drop or buffer 540 of the frame according to the transmission rate of the network and the quality of service set based on the time stamp extracted from the frame flowing through the network connection 510. Rearrange the frame to be selected. The RTP packet, which is a transmission protocol for real-time processing data, includes a timestamp field in which the system time of the transmitting system is recorded. The error detector 560 extracts and compares a timestamp value from an RTP packet to measure and store the transmission time between frames, thereby grasping the concentration and tendency of the network, thereby setting up flow control and quality of service at a higher level. It performs the function to make this possible.

8 is a diagram showing the detailed configuration of the error detection unit. Referring to FIG. 8, the error detector 560 includes a data extractor 562, a data storage 564, an operation unit 566, an operation value storage unit 568, and a reordering unit 570.

The data extractor 562 extracts error detection data including a time stamp and a sequence number from a frame flowing through the network connector 510. The data storage unit 564 stores the extracted error detection data. The calculator 566 compares the data extracted from the first frame currently introduced from the error detection data stored in the data storage unit 564 with the data extracted from the previously introduced second frames. The arithmetic value storage unit 568 stores a difference value between the transmission time of the first frame and the second frames, which are the comparison results of the arithmetic unit 566. The reordering unit 570 rearranges the selection target frame stored in the drop or buffer 540 of the frame according to the transmission speed of the network determined based on the difference value of the transmission time and the set quality of service. When data is transmitted through Ethernet, when the packet transmission order is changed due to the difference of routing paths in the network, the data that can be transmitted using the IP protocol is about 1500 bytes per frame, which greatly affects the quality of service. It is a factor of the degree that can give. If the changed sequence number difference is within the delay guaranteed by the quality of service, the frame is dropped if it exceeds the capacity of the buffer 540.

9 is a flowchart illustrating a process of performing a MAC control method for high speed multimedia streaming according to the present invention.

Referring to FIG. 9, the filtering controller 520 determines whether or not to process a frame flowing from a server providing multimedia data through Ethernet and a parameter used for the screen to process the frame (S900). The input data counting unit 532 of the filtering engine 530 combines and counts the frame data in the form of a serial bit stream coming from the server in units of bytes to determine a field having a parameter value used for screening among fields constituting the frame. Specify the location (S910). The comparison unit 536 of the filtering engine 530 selects the field value recorded in the field corresponding to the designated position among the fields constituting the frame flowing from the server, and is previously set and stored in the parameter storage unit 534. At least one parameter used in the process is compared, and when the comparison target values match, the frame flowing from the server is determined as the selection target frame (S920).

The buffer 540 stores the frame determined as the screening target frame by the filtering engine 530 (S930). In addition, the data extraction unit 562 of the error detection unit 560 extracts error detection data including a time stamp and a sequence number from a frame flowing from the server (S940). Next, the operation unit 566 of the error detector 560 compares the data extracted from the current first frame and the data extracted from the second second frame (S950) and outputs a comparison result (S950). The difference between the transmission time of the first frame and the second frame, which is a result of the comparison of the operation unit 566 of the error detector 560, is stored in the result value storage unit 568 (S960). The reordering unit 570 of the error extractor 560 selects a frame to be dropped or stored in the buffer 540 according to the transmission speed of the network determined based on the difference value of the transmission time and the set quality of service. Rearrange (S970).

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

According to the MAC control apparatus and method for high-speed multimedia streaming according to the present invention, the filtering engine and the error detection unit performs the main CPU, the operating system and the network data processing functions to be performed by the application program with dedicated hardware that can be implemented in a simple form, the main By freeing up CPU resources, the performance of the entire embedded system can be avoided. The separate frame buffer and data bus of real-time processing data reduces the data transfer bandwidth between the main CPU and peripherals, improving overall system performance. You can expect. In addition, the quality of service is kept constant by absorbing and averaging changes in real-time data rates that are unpredictable due to TCP / IP packet transmission using a circular buffer in the media MAC controller. Let's do it.

Claims (13)

A network connection unit connected to a physical network to transmit and receive data to and from a server providing multimedia data through Ethernet; A filtering control unit which determines whether or not to sort the frame introduced through the network connection unit and determines a parameter used for the sorting process for the frame; A filtering engine for selecting and outputting a screening target frame based on the parameter from among frames introduced through the network connection unit when the screening process for the frame is determined by the filtering controller; And And a buffer for storing a high-speed large-capacity sorting processing frame input from the filtering engine. The method of claim 1, The filtering engine, An input data counting unit which combines and counts frame data in the form of a serial bit stream flowing through the network connection unit in units of bytes to designate a position of a field having a parameter value used for screening among fields constituting the frame; A parameter storage unit for storing at least one parameter used for the selection process determined by the filtering control unit; If a field value recorded in a field designated by the input data coefficient unit and a parameter value stored in the parameter storage unit are identical among the fields constituting the frame flowing through the network connection unit, the frame is introduced through the network connection unit. Comparing unit for determining the selection frame; And And a demultiplexer configured to output, to the buffer, a frame determined by the comparator from among the frames flowing through the network connection unit, to the buffer. The method according to claim 1 or 2, The parameter is selected from at least one of a protocol type, an IP port number, a protocol number and a MAC address to be used individually or in combination to determine whether to process the frame selection MAC control device for high-speed multimedia streaming . The method of claim 3, wherein When the parameters are used in combination, the application order of the plurality of parameters stored in the parameter storage unit is set in advance, and the parameters are sequentially input from the parameter storage unit to the comparison unit in accordance with the set application order. MAC control device for high-speed multimedia streaming, characterized in that. The method according to claim 1 or 2, The error detection unit realigns the drop frame or the sorting target frame stored in the buffer according to the transmission rate of the network and the set service quality measured based on the time stamp extracted from the frame flowing through the network connection unit. MAC control device for high-speed multimedia streaming comprising a. The method of claim 5, The error detection unit, A data extraction unit for extracting error detection data including a time stamp and a sequence number from a frame flowing through the network connection unit; A data storage unit for storing the extracted error detection data; An operation unit which compares the data extracted from the first frame currently introduced from the error detection data stored in the data storage unit with the data extracted from the previously introduced second frames; An operation value storage unit for storing a difference value between transmission times of the first frame and the second frame as a comparison result of the operation unit; And A reordering unit for rearranging a drop frame or a selection target frame stored in the buffer according to a transmission speed of the network and a set quality of service determined based on the difference in the transmission time; MAC controller for streaming. The method according to claim 1 or 2, And an interface bus for reducing a transmission bandwidth between the buffer and the central processing unit that reads out and processes the selection target frame stored in the buffer. (a) determining whether or not to sort the frames from the server providing the multimedia data through Ethernet and to determine the parameters used for the sorting on the frames; (b) if the screening process for the frame is determined, selecting and outputting a high speed and large capacity screening target frame based on the parameter from the frames flowing from the server; And (c) storing the screening target frame in a buffer; MAC control method for high-speed multimedia streaming comprising a. The method of claim 8, In step (b), (b1) combining and counting frame data in the form of a serial bit stream coming from the server in units of bytes to designate a position of a field having a parameter value used for screening among fields constituting the frame; (b2) comparing a field value recorded in a field corresponding to the designated position among the fields constituting the frame flowing from the server with at least one parameter used in a predetermined sorting process; And (b3) if the field value and the parameter match, determining the frame from the server as the selection target frame; MAC control method for high-speed multimedia streaming, characterized in that it comprises a. The method according to claim 8 or 9, The parameter is a MAC control method for high-speed multimedia streaming, characterized in that at least one or more selected from the type of protocol, IP port number, protocol number and MAC address are selected individually or combined to determine whether to process the frame selection. . The method of claim 10, In the step (b2), when the parameters are used in combination, the values of the fields and the plurality of preset parameters are sequentially compared with the detection order of the fields corresponding to the designated positions. MAC control method for high speed multimedia streaming. The method according to claim 8 or 9, (d) dropping the frame or reordering the selection target frame stored in the buffer according to the transmission rate of the network and the set quality of service measured based on the time stamp extracted from the frame flowing from the server. MAC control method for high-speed multimedia streaming comprising a. The method of claim 12, In step (d), (d1) extracting error detection data including a time stamp and a sequence number from a frame flowing from the server; (d2) storing the extracted error detection data; (d3) comparing the data extracted from the first frame which is currently introduced and the data extracted from the second frame which have been previously introduced among the stored error detection data; (d4) storing a difference value between transmission times of the first frame and the second frame; And (d5) reordering the selection target frame stored in the buffer or dropping the frame according to the transmission speed of the network determined based on the difference value of the transmission time and the set quality of service; MAC control method for high speed multimedia streaming.

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