KR20040074805A - A method of providing streaming service and a system thereof - Google Patents

Abstract

PURPOSE: A method and a device for a streaming service are provided to reduce the load of a server and the traffics of a network by offering the needed data in real-time and using the stored data, not receiving the same data again, for the repetitive playback, while performing the playback even if all needed data is not received. CONSTITUTION: A playback program(31) transmits a command(40) for requesting a file of the multimedia data to a client module(30) or changing a playback position, and receives/plays the stream data(44) from the client module. A control module(32) makes the client module process the received command. If a separated command is not received from the playback program, the control module requests a transmitting/receiving module(35) to receive the data before a needed time by calculating an offset of the needed data. A multimedia data storage(34) functioning as a cache stores/provides the data if the playback program requests the data until the data is removed. The transmitting/receiving module receives a part of the data requested from the control module from the multimedia data to be played and stores the data in the multimedia data storage.

Description

Streaming service method and device {A METHOD OF PROVIDING STREAMING SERVICE AND A SYSTEM THEREOF}

The present invention is a method for receiving multimedia data such as video or voice through electronic circuits, and receiving the multimedia data in parallel and playing the data before the entire data is transmitted, and continuously receiving the data even during multimedia playback. And to an apparatus.

The Internet has paved the way for a dramatic shift in the acquisition path. Currently, all kinds of information that can be obtained offline can be searched through the Internet, and the role of the acquisition path is gradually increasing due to the advantages of speed and convenience. Along with the Internet, one of the major factors that improved the distribution channel of information is the World Wide Web. Using the World Wide Web, users can easily and quickly search for the information they need through a convenient and intuitive interface. Information distributed over the Internet was mainly dominated by text-based data. In the past, due to the lack of computer technology and communication technology, there was a shortage of storing and transferring large amounts of data, and the data composed of small texts occupied most of the data. However, as the limitations on computer technology and communication technology are gradually overcome, multimedia data such as video and voice are becoming mainstream among information distributed through the Internet.

Multimedia data such as video and audio are generally larger than text data. Since transmitting large data over the Internet requires more time than transmitting small data, transmitting multimedia data takes much more time than transmitting text data. Accordingly, there is a need for a new method for transmitting multimedia data over the Internet and reproducing the received data.

The most common way to transfer information over the Internet is by downloading. This has been widely used since the time of transmission of text-based information in the past, and the user stores the entire data file found on the Internet on his computer and then uses it. The download method can be applied to multimedia data, and the download method can only be used to service data in a file format that does not support streaming, that is, a format such as AVI or DIVX without using a streaming server. In this case, however, the user can play the multimedia only after the entire data file has been received, so the user has to wait a long time until the reception of the data is completed.

In addition to the larger size of the multimedia data than other data, the multimedia data is sequentially and regularly read and reproduced. That is, the multimedia data is played in a predetermined order according to the passage of time in moving the multimedia data and playing the voice or video, and there is no problem for the user to use the multimedia if only the data corresponding to the played part is provided. This feature eliminates the need to store the entire data file to drive multimedia data. That is, not all data must be present in order to reproduce a large amount of multimedia data corresponding to one hour of video, but only data corresponding to the portion being played can be played back.

Because of these features, streaming has been devised for the transmission and operation of multimedia data. That is, when a user wants to play multimedia data through an electronic network, the server starts receiving data from the server, starts playing when the data is filled in a buffer of a predetermined size, and the server in real time according to the speed of consuming data during playback. Receive data from the unit so that playback is not interrupted. The technical definition of streaming is as follows.

"Streaming is a way to send data that is regularly and continuously processed, so that an application that processes data before streaming completes the entire file of the desired data using streaming can drive the data."

Unlike the download method, the streaming method is sensitive to the data transmission speed because only the necessary data is received and reproduced in real time without the entire multimedia data stored. That is, when the transmission speed is slower than the rate at which the reproduction program reproduces data, the reproduction of audio or moving images occurs. Therefore, when multiple users access the same server at the same time, normal service cannot be provided. To avoid this, the number of users connecting to one server should be strictly limited. As the work of playing multimedia is highly dependent on the data transmission speed, it is difficult to provide a high quality or sound quality, and in particular, the size of the screen is limited. This is because as the image quality or sound quality increases or the screen size increases, the amount of data required for reproduction per unit time increases rapidly, and as a result, high-speed data transmission is required.

The streaming method that transmits data in real time does not store multimedia data on the user's computer. Therefore, in order to repeatedly play the part that has already been played, the data must be received from the server again. This creates an unnecessary load.

The ultimate technical problem of the present invention is to compensate for the disadvantages of the download method and the streaming method, and take advantage of the data. In case of transmission, it is provided in real time, and in the case of repeated playback as in the download method, it is to reduce the load on the server and the traffic of the electronic network by using the stored data without receiving the same data again.

Detailed technical tasks for this purpose are to receive data in parallel from multiple data sources instead of one server to increase transmission speed and support real-time (parallel transmission); Providing a reproduction program with data of a portion necessary for reproduction so as to enable reproduction of multimedia even when all data to be reproduced is not transmitted (streaming service); Preventing the reproduction quality from being deteriorated in accordance with the transmission rate by receiving the necessary portion in advance in order of playing the multimedia data (predictive transmission); When repeating reproduction, the same data is not repeatedly received using the stored data (data storage); It provides a function to prevent the stored data from being copied to other users and being reproduced without any unauthorized copying.

1 is a structural diagram of an information processor.

Figure 2 is an illustration of a physical environment to which the present invention is applied.

3 is a block diagram of a functional module performed in a server.

4 is a block diagram of a functional module performed in an information processor.

5 is a flowchart of the operation when the control module receives the playback start command.

6 is a flowchart illustrating the operation when the control module receives a playback command such as stop, stop, jump, and the like.

7 is a flowchart of the operation in which the control module predicts a portion of data necessary for reproduction.

8 is a flow chart of the transmission and reception module.

9 is an exemplary diagram of parallel transmission.

10 is an exemplary view of a copy protection function by encryption.

Since the present invention can be applied to any device having a function of reproducing digitized multimedia data, hardware to which the present invention is applied is defined as shown in FIG. 1 and is called an information processor.

2 illustrates a physical environment to which the present invention is applied. The server and each information processor may request or receive data by performing data communication with each other through an electronic network. At this time, the server stores the multimedia data to be serviced and manages the information (location information) on the role of transmitting when a user's request is generated and on which information processor the multimedia data stored in the server is stored.

3 illustrates a functional module performed at the server. The server is largely composed of an apparatus 21 for storing multimedia, a database 22 for managing which multimedia data is stored in which information processor, and a module 23 for receiving a request for the server and transmitting a result thereof. It is. When the data request is received from the information processor, it transmits the requested multimedia data, and when the location information about the specific multimedia data is requested, it is responsible for transmitting the information about it. According to the present invention, unlike a conventional service method in which one server serves the entire multimedia data to be played, the data to be played in parallel is transmitted, and the client information processor for playing the multimedia data is frequently required to play the part. As it requests and receives, the unit of data requested and received by the information processor becomes a specific part of the file, not the file. Thus, data as requested or transmitted by the information processor refers to a particular portion of the multimedia data file. At this time, when the information processor requests and receives multimedia data of a part necessary for reproduction, the segment identifier of the corresponding multimedia data file or the physical offset in the file is used. An example of the location information database used in the present invention has the following structure.

<Multimedia file name, information processor 1, information processor 2, ..., information processor n>

If the location information is further subdivided and the multimedia data file is managed in segments, the location information database may be configured in the following structure.

<Segment of multimedia file, information processor 1, information processor 2, ..., information processor n>

Figure 4 shows a functional module in the information processor for providing a function provided by the present invention. The player program 31 is an application program for playing multimedia data such as a Windows media player or a real player. The player program 31 transmits a command 40 to the client module 30 to request a file to be played or to change a play position. A function of receiving and reproducing the stream data 44 from the 30 is performed. The control module 32 of FIG. 4 receives the command 40 of the multimedia data to be reproduced, plays, stops, moves the position, etc., and controls the processing in the client module 30. If there is no separate command from the reproduction program, an offset of data required for reproduction is calculated and requested to the transmission / reception module 41 so that it can be received before the required time point. The role played by the control module 32 is illustrated in FIGS. 5, 6 and 7. FIG. 5 is a flowchart when a playback program starts playing multimedia data, FIG. 6 is a flowchart when a user performs a command related to playback during playback, and FIG. 7 predicts a data portion required for future playback during playback. It is a flow chart of the function to make receiving.

The multimedia data storage 34 of FIG. 4 functions as a kind of cache, and serves to store the requested data once and to provide the data when requested by the playback program until it is evicted. The size of the storage location may be variable or fixed, and the unit to be stored may be a data unit such as a segment or a file unit, and is determined according to the requirements of the implementor or the field of use, such as determined by a policy that applies at the time of extraction. It can be applied differently.

The transmission / reception module 35 of FIG. 4 performs a function of receiving data of a portion requested by the control module 32 from the multimedia data to be reproduced and storing the data in the multimedia data storage 34. This function is shown in FIG. For this purpose, the control module provides information on the physical location (offset) of the data file being reproduced by the transmission / reception module, and the transmission / reception module performs an operation for receiving it. According to the flow chart shown in Figure 8, for the data request received from the control module, if it is already stored in the data storage or whether the reception is in progress, and if it is necessary to request a new reception, the requested data using the location information Request the information processor or server to start the transmission, and if it receives the data, encrypt it and store it in the data storage.

In this case, when the data to be received are stored in several information processors, each of them is received in parallel from each or all of the information processors, and an example thereof is illustrated in FIG. 9. This example shows an example in which data to be received is transmitted in parallel by three information processors and one server. The data 51 requested by the control module is composed of four blocks, and the position information 52 includes these data. It is shown that blocks can be transmitted from three information processors and one server. The client does not receive data sequentially from three information processors and one server, but opens four communication channels in parallel and receives them in parallel. At this time, the data transmitted from each is adjusted in the transmission and reception module so as not to overlap each other.

The stream generation module 33 of FIG. 4 serves to read data required for the reproduction program 31 from the multimedia data storage 34 to be supplied to the reproduction program. In general, since a playback program takes data necessary for playback into a buffer in the storage device and plays the data, the stream generation module fills the buffer at the speed required by the playback program. . Since the data is encrypted and stored when the data is stored in the multimedia data storage location by the transmission / reception module 35, the stream generation module decrypts the encrypted data. The encryption or decryption method is beyond the scope of the present invention, and if the encryption method is disclosed, a method for illegally using a copy is also disclosed, so detailed description of encryption is omitted in the present invention.

Referring to the configuration of each functional module of FIG. 4, it can be seen that the transmission / reception module 35 and the stream generation module 33 operate in pairs. That is, the multimedia data required for the playback program to be stored is stored in the multimedia data storage 34, the role of bringing the data from the outside only the transmitting and receiving module, the stream generation module is to play the stored data It serves to provide to (31). When the transmitting / receiving module stores data in a multimedia data storage location, the transmitting / receiving module stores the data in a form that can be read only by the stream generation module belonging to the same client module so that the received data is not reproduced when the received data is copied to another information processor. 10 illustrates such a relationship.

The transmission / reception module of the client module of the information processor to reproduce the multimedia data checks the location information from the server, checks the list of information processors having the data to be received, and receives each information processor to receive the data corresponding to the required portion. Or request data from the server, and receive the data in parallel independently from each other. Such parallel transmission reduces the time required for data transmission. For example, if 2 Mbps can be transmitted from each information provider, a transmission effect of 10 Mbps occurs when received in parallel from five information providers. This parallel transmission makes the data transmission rate stable. That is, when data is received from one information provider, for example, one server, the transmission speed is not constant and irregular due to the generation of load by other tasks performed by the server. However, when transmitting in parallel from multiple information providers, the variation in the overall transmission rate is reduced, thereby enabling stable transmission. In addition, in parallel transmission, the entire file is not processed by one information provider for one data request, but is processed by a plurality of information providers. Therefore, load distribution is also effected.

Also, the present invention does not sequentially transmit data, but requests data by calculating a physical offset in accordance with the order in which a client requesting multimedia data plays, and sequentially providing the received data to a playback program. This enables the streaming service on its own without adding the streaming function to the server. As a result, not only protocols for streaming transmission can be used during server and client information processing, but also general transport protocols are easy to implement.

In addition, in the present invention, by using a codec used to play the multimedia data, the playback program predicts the order required for the playback, calculates the physical offset, and receives the data in advance before the data is needed to enable stable playback. do.

In addition, the present invention stores the data once received in a storage area having a cache function, so that when data is repeatedly played back or replayed, a separate data transmission / reception does not occur. It eliminates the necessary replay preparation time and reduces the load on the server.

In addition, in the present invention, reproduction can be performed only in the information processor which receives data by introducing encryption.

Claims (1)

In the method for playing multimedia data, A first step of predicting data necessary for playing multimedia and calculating a physical offset; Requesting and receiving data using the predicted offset; A third process of encrypting and storing the received data; And a fourth process of decoding the stored data and providing the same to the playback program.