KR101479337B1

KR101479337B1 - Push-to-talk over celleular box provided in push-to-talk over celleular system and method for processing media data thereof

Info

Publication number: KR101479337B1
Application number: KR20080057815A
Authority: KR
Inventors: 이지혜; 박성진; 김대원
Original assignee: 삼성전자주식회사; 이화여자대학교 산학협력단
Priority date: 2008-06-19
Filing date: 2008-06-19
Publication date: 2015-01-12
Also published as: KR20090131854A

Abstract

The present invention provides a PoC box provided by a PoC system and a media data processing method therefor. A PoC box according to the present invention receives media data from a PoC server, converts the received media data into stream data, and stores the stream data. The PoC box also generates and stores session control information for the converted stream data.

PoC box, client, server, media data, stream data, session control information, live streaming

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a PoC box and a media data processing method using the PoC box. 2. Description of the Related Art [0002]

The present invention relates to a PoC box provided in a PoC system and a media data processing method therefor.

Due to the breakthrough of mobile communication and the expansion of communication networks, various services and applications using mobile phones have been provided. In addition, users' needs have been diversified to extend from simple call service to location service, multimedia service PTT (Push To Talk, hereinafter referred to as PTT) service. In particular, the PTT service supports a variety of additional functions such as instant messenger and status display as well as group call and voice call, which were possible in conventional radio and TRS (Trunked Radio System).

Currently, the establishment of standards for Push-to-talk Over Cellular (PoC) service that introduces the PTT concept into a mobile communication network is actively being discussed. One of the characteristics of the PoC service distinguished from the existing mobile communication service is that the user belongs to a plurality of sessions and can make a call while moving between sessions as needed. The requirement that a user be able to talk while moving between multiple sessions is specified in the requirements of the Open Mobile Alliance (OMA), an organization that defines mobile services.

Meanwhile, in order to further expand the PoC service, in the OMA PoC Release 2, a Poc box service similar to a voice mailbox is considered. PoC box service means that a user who can not participate in one-to-one or group sessions in real time can participate in a specific physical or logical system on behalf of his or her client. At this time, the PoC box stores the media transmitted to the client in the session, and then transmits the stored media in response to the request of the PoC client.

There is no method of defining how to handle media in a session in the PoC box with respect to the current PoC box service. Therefore, in implementing the PoC service, it is necessary to define a method of processing the media transmitted to the PoC box and a method of providing the PoC client with the media stored in the PoC box.

It is an object of the present invention to provide a method and apparatus for a PoC box to process media data in a PoC system.

In a PoC system including a PoC (Push-to-talk Over Cellular) server and a PoC box connected to the PoC server according to the present invention, the PoC box processes media data by receiving media data from a PoC server Temporarily storing the media data; converting the temporarily stored media data into data stream data that can be transmitted in a streaming manner capable of real-time playback; generating session control information for the converted stream data; Stream data, and session control information.

A PoC box for processing media data together with a PoC server in a PoC (Push-to-talk Over Cellular) system according to the present invention is a PoC box for storing media data received from a PoC server as stream data A session information generator for generating session control information for the converted stream data, and a data storage for storing the converted stream data and session control information.

According to the present invention, a PoC box provided by a PoC system and a media data processing method by the PoC box are provided.

In addition, the PoC box can stream the media data requested by the PoC clients that are not participating in the session in real time and transmit the media data in real time, thereby enabling the PoC client to display the media data even if the PoC client does not receive the media data.

In addition, the PoC box can transmit only a part of the media data required by the PoC client through real-time streaming transmission of the media data, thereby reducing the data transmission amount and reducing the waiting time for the PoC client to receive the media data.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be noted that the same components in the drawings are denoted by the same reference numerals whenever possible. In the following description and drawings, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention unnecessarily obscure.

1 is a diagram illustrating a PoC system according to an embodiment of the present invention.

The PoC system according to the present embodiment includes a PoC client 10, a PoC server 20, and a PoC box 30.

The PoC client 10 is a service requestor built in a PoC terminal, and resides in a PoC terminal, and performs a network connection to provide a PoC service to a PoC service subscriber. Also, the PoC service subscriber is provided with the PoC service through the PoC terminal having the PoC client 10 built therein. Hereinafter, the term 'PoC client' is used generically to refer to terminals and PoC service subscribers in which the PoC client 10 is installed.

The PoC client 10 establishes a PoC session in the PoC service subscriber, that is, the PoC user, participates in the established existing session, and ends the preset session. In addition, the PoC client 10 can perform a function of creating and delivering a talk burst, a function of supporting an instant personal alert, and an authentication function of accessing a PoC service.

The PoC server 20 is connected to a SIP (Session Initiation Protocol) / IP (Internet Portocol) core network (not shown) to provide a PoC service to the PoC client 10. The PoC 20 server performs an overall PoC control function (PoC Control Function) for maintaining and managing a PoC session established between PoC clients 10. Also, the PoC server 20 can perform a PoC participation function (Participating PoC Function) for maintaining a session for participating in a PoC session established for a one-to-one call or a multi-party call between the PoC clients 10. [

The PoC box 30 stores the media data transmitted from the PoC server 20. [ The media data stored in the PoC box 30 may include audio data, video data, voice, text, and an image. The PoC box 30 according to the present embodiment stores the PoC client 30 in the PoC box 30 when the PoC client 10 fails to receive media data generated in another session other than the session in which the PoC client 10 is participating.

For example, it is assumed that the PoC client 10 having the first and second sessions is established. It is also assumed that the PoC client 10 is participating in the first session and media data to be transmitted to the PoC client 10 in the second session is generated. When the PoC client 10 is participating in the first session, it can not participate in the second session and thus can not receive the media data. The PoC server 20 transmits the media data of the second session that the PoC client 10 can not receive to the PoC box 30 and stores the media data. The PoC box 30 transmits the media data to the PoC client 10 when the PoC client 10 ends the connection with the first session.

In this embodiment, the PoC client 10 has not received the media data generated in the other sessions other than the participating session. However, according to another embodiment, the PoC client 10 can not receive the media data Data may be transmitted to the PoC box 30 and stored in advance.

2 is a flowchart illustrating a method of processing media data in a PoC system according to an embodiment of the present invention.

The PoC server 20 transmits the media data to the PoC box 30 (S102). At this time, the PoC box 30 can temporarily store the media data received from the PoC server 20. [ If the PoC client 20, which is the destination of the media data, is unable to receive the current media data, such as participating in another session, the PoC server 20 transmits the corresponding media data to the PoC box 30 and stores the media data .

The PoC box 30 converts the media data received from the PoC server 20 into stream data (S104). The stream data indicates that the media data is converted into data that can be streamed in real time.

The PoC box 30 generates session control information for the stream data (S106), and stores the stream data and session control information (S108). The session control information includes information on the stream data, for example, the file name of the media data before being converted, the file name of the stream data after the conversion, the PoC client ID of the PoC client 10 to receive the media data, (Capacity) of the PoC server 20, the time at which the media data is transmitted from the PoC server 20, the location where the stream data is stored, and the like.

When the PoC client 10 can receive media data, the PoC server 20 notifies the PoC client 10 that media data has been received (S110). The PoC server 20 according to the present embodiment can notify that the corresponding media data is converted into stream data and stored in the PoC box 30. [ The PoC client 10 accesses the PoC box 30 and requests that the media data be transmitted (S112). At this time, the PoC client 10 may transmit a PoC client ID of the PoC client 10 in the transmission request.

Upon receiving the media data transmission request from the PoC client 10, the PoC box 30 determines stream data corresponding to the media data requested by the PoC client 10 using the session control information (S114). The PoC box 30 can retrieve the session control information having the PoC client ID that matches the PoC client ID included in the transmission request of the PoC client and find the corresponding stream data using the retrieved session control information.

The PoC box 30 transmits the stream data through a Real Time Transport Protocol (RTP) (S116). The PoC client 10 plays back the stream data received from the PoC box 30 in real time (S118).

When the PoC box 30 transmits stream data through the RTP scheme, the PoC client 10 can control and reproduce the stream data to be transmitted. For example, when the PoC client 10 plays back a 5-minute moving picture, the PoC client 10 notifies the PoC client 30 ). The PoC box 30 can transmit the stream data requested by the PoC client 10 to the PoC client 30 first and the stream data corresponding to the rest of the stream data can be transmitted to the PoC client 30 It can also be transmitted after transmission.

3 is a block diagram showing a schematic configuration of a PoC client and a PoC box in a PoC system according to an embodiment of the present invention.

The PoC client 10 includes a first communication interface unit 42, a key input unit 44, a multimedia reproducing unit 46, a memory 48, and a first control unit 50.

The first communication interface unit 42 performs a wired / wireless communication function of the PoC client 10. The first communication interface unit 42 according to the present embodiment performs communication with the PoC server 20 and the PoC box 30. In addition, the PoC server 20 can communicate with other PoC clients to transmit and receive data. The PoC client 10 according to another embodiment includes an RF (Radio Frequency) transmitter (not shown) for up-converting and amplifying a frequency of a transmitted signal, an RF receiver (not shown) for low- City), and the like.

The key input unit 44 includes a key for inputting numbers and characters, and a key for setting various functions, and receives input from a user. The key input unit 44 according to the present embodiment can detect the key input according to the transmission and reception of the RTP method.

The key input unit 44 according to the present embodiment may include keys for reproducing audio or video data, for example, keys for playing, stopping, fast forwarding, rewinding, and pausing.

The memory 48 may be constituted by a program memory and a data memory. The memory 46 stores various types of information necessary for controlling the operation of the PoC client 10. [ The memory 48 according to the present embodiment can store media data or stream data transmitted from the PoC box 30. [

The multimedia reproducing unit 46 reproduces the multimedia data stored in the memory 48. The multimedia reproducing unit 46 according to the present embodiment can reproduce stream data transmitted from the PoC box 30 in real time.

The first control unit 50 controls the overall operation of the PoC client 10. The first control unit 50 according to the present embodiment can reproduce the stream data being transmitted through the multimedia playback unit 46 in real time when the PoC client 10 is receiving stream data. The PoC box 30 can also receive a key input such as playback, stop, fast forward, rewind, and pause through the key input unit 44 and transmit the stream data corresponding to the received key input .

The PoC box 30 includes a data conversion unit 64, a session information generation unit 66 and a data storage unit 68. The PoC box 30 further includes a second communication interface unit 62 and a second control unit 74 Lt; / RTI >

The second communication interface unit 62 can perform communication with the PoC client 10 and the PoC server 20. [ The second communication interface unit 62 receives the media data transmitted from the PoC server 20 and transmits the stream data stored in the data storage unit 68 to be described later to the PoC client 10. The second communication interface unit 62 according to the present embodiment may receive a transmission request message requesting transmission of media data from the PoC client 10. [ When the media data requested by the PoC client 10 is not converted into the stream data, the second communication interface unit 62 transmits the stream data to the PoC client 10 via the corresponding data stored in the data storage unit 68 under the control of the second control unit 74, It is possible to transmit the media data to the PoC client 10. [

The data conversion unit 64 converts the media data transmitted from the PoC server 20 into stream data. To this end, the data conversion unit 64 divides the media data into packet units under the control of the second control unit 74, which will be described later. Hereinafter, media data divided in units of packets will be referred to as a 'media packet'. The data conversion unit 64, which divides the media data into at least one media packet, generates RTSP time information corresponding to each media packet. In addition, the data conversion unit 64 adds the generated RTSP time information to the corresponding media packet. Thus, the media data is converted into stream data.

The RTSP time information is time information of each media packet divided by the data converting unit 64. When the stream data is played back in real time by the PoC client 10, And information on the playback time of the portion. For example, it is assumed that audio data having a total reproduction time of 5 minutes is converted into stream data by the data conversion unit 64. [ It is also assumed that the data conversion unit 64 divides the audio data into media packets each having a reproduction time of one minute. If the reproduction time of any of the media packets divided by the data conversion unit 64 is '1 minute 1 second ~ 2 minutes 0 second' among the entire reproduction time of the stream data, the total reproduction time of the media packet is one minute , It can be the RTSP time information that the media packet occupies the playback time corresponding to '1 minute 1 second to 2 minutes 0 seconds' in the reproduction time of the entire stream data.

In addition, it is assumed that the PoC client 10 requests stream data to the PoC box 30 to reproduce from a portion corresponding to '1 minute and 1 second' during the entire playback time. The PoC box 30 in the PoC system according to the present embodiment transmits a media packet corresponding to '1 minute 1 second ~ 2 minutes 0 seconds' to a media packet corresponding to '0 minutes 0 seconds ~ 1 minute 0 seconds' To the PoC client (10). That is, the PoC box 10 assigns different priorities to the media packets classified according to the RTSP time information to transmit the media packets preferred by the PoC client 10 first, and to transmit the other media packets later You can adjust your turn. At this time, the PoC client 10 can receive a command such as play, stop, fast forward, rewind, and pause of the key input unit 44 and transmit a corresponding transmission request to the PoC box 30.

The session information generation unit 66 generates session control information for the stream data converted by the data conversion unit 64. The session control information includes a file name of the media data before being converted into the stream data, a file name of the stream data after the conversion, a PoC client ID (ID) of the PoC client 10 to receive the media data, The time at which the media data is transmitted from the PoC server 20, the location where the stream data is stored, and the like. In addition, the session control information may include information on each media packet constituting the stream data, that is, RTSP time information, file type, size (capacity), storage location, etc. of each media packet.

The session information generation unit 66 generates session control information for the media data received from the PoC server 20 under the control of the second control unit 74. [ The session control information on the media data includes a file name of the media data, a PoC client ID of the PoC client 10 to be received media data, a type and a size of the stream data, The location where the stream data is stored, and the like.

In addition, the session control information generated by the session information generation unit 66 may be in the form of XML (Extensible Markup Language).

The data storage unit 68 stores the stream data converted by the data conversion unit 64 and the session control information generated by the session information generation unit 66. [ The data storage unit 68 according to the present embodiment may store the media data transmitted from the PoC server 20. [

The data storage unit 68 according to the present embodiment may include a session information storage unit 70 for storing session control information and a stream data storage unit 72 for storing stream data. The stream data storage unit 72 may store media data transmitted from the PoC server 20 under the control of a second control unit 74, which will be described later.

The second control unit 74 controls the overall operation of the PoC box 30.

The second control unit 74 according to the present embodiment determines whether or not the media data received from the PoC server 20 is streamable data. For example, when the media data is audio data or video data, the second control unit 74 determines the corresponding media data as streamable data, and determines that the media data can not be streamed if the media data is text, image, or voice have.

When the received media data is streamable data, the second control unit 74 controls the data conversion unit 64 to convert the media data into stream data. And controls the session information generator 66 to generate session control information for the stream data. If the media data transmitted from the PoC server 20 is not streamable data, the second controller 74 controls the session information generator 66 to generate session control information for the media data.

Thus, the PoC box 30 according to the present embodiment can manage the media data requested to be transmitted by the PoC client 10 using only the session control information stored in the data storage unit 68. The PoC box 30 can retrieve the session control information stored in the PoC box 30 to find out whether the media data requested to be transmitted by the PoC client 10 exists. The second control unit 74 searches the session control information including the same information as the file name of the media data requested to be transmitted from the PoC client 10 among the session control information stored in the data storage unit 68, It can easily be determined whether or not the data is stored in the PoC box 20. [

4 is a flowchart illustrating a method of processing media data by a PoC box according to an embodiment of the present invention.

The second communication interface unit 62 of the PoC box 30 receives the media data from the PoC server 20 (S122). At this time, the data storage unit 68 of the PoC box 30 may temporarily store the media data transmitted from the PoC server 20 under the second control unit 74.

The data conversion unit 64 divides the received media data into packet units (S124), and generates RTSP time information corresponding to the media data, i.e., media packets, divided in units of packets (S126). The data converting unit 64 adds the corresponding RTSP time information to media data in units of packets, i.e., media packets (S128). Thus, by passing through steps S124 to S128, the media data is converted into stream data.

The data conversion unit 64 according to the present embodiment can separate the media data first from the video data and the audio data if the media data is video data including both video and audio data. Thereafter, the data conversion unit 64 divides the video data and the audio data into packet units, and generates RTSP time information corresponding to each media packet.

The session information generation unit 66 generates session control information corresponding to the stream data (S130). The session control information includes information on the stream data. The session control information includes a PoC client ID, a file name of the media data, a storage location at which the stream data is stored, a time at which the media data is transmitted from the PoC server 20, and a total reproduction time of the stream data. In addition, the session control information may include information on media packets constituting the stream data.

The data storage unit 132 stores stream data and session control information (S132). The data storage unit 132 according to the present embodiment can store stream data and session control information in association with each other under the control of the second control unit 74. [

5 is a flowchart illustrating a method of processing media data by a PoC box in a PoC system according to an embodiment of the present invention.

The PoC box 30 receives the media data from the PoC server 20 (S142). The second control unit 74 of the PoC box 30 determines whether the received media data is data that can be reproduced in a streaming manner (S144). The second controller 74 according to the present embodiment can analyze the media data received in step S142 to find out the type of the media data. If the type of the media data is, for example, audio data, video data, or the like, the second control unit 74 determines that the data is reproducible by the streaming method. On the other hand, if the type of the media data is, for example, an image, text, voice, or the like, it is determined that the media data is not data that can be reproduced by the streaming method.

If the media data is not data that can be reproduced in a streaming manner (S144: NO), the media data is stored in the data storage unit 68 (S146). Thereafter, the session information generator 66 of the PoC box 30 generates session control information for the media data under the control of the second controller 74, and stores the generated session control information in the data storage 70 (S150).

If the media data is data that can be reproduced in a streaming manner (S144: Yes), the data conversion unit 64 converts the media data into stream data, and the converted stream data is stored in the data storage unit 68 (S150) . The session information generation unit 66 generates session control information for the stream data converted in step S150, and the generated session control information is stored in the data storage unit 68. [

When the PoC client 10 requests the PoC client 30 to transmit the media data to the PoC client 30 at step S152, the second controller 74 of the PoC box 30 transmits the media data requested to be transmitted from the PoC client 10 It is determined whether or not session control information having the same PoC client ID exists (S154). The PoC client 10 according to the present embodiment may transmit a transmission request message to the PoC box 30 to request the PoC box 30 to transmit the media data. In addition, the transmission request message may include the PoC client ID of the corresponding PoC client. Accordingly, the second control unit 74 of the PoC box 30 can analyze the transmission request message to find the PoC client ID requesting transmission of the media data. The second controller 76 determines whether there is a PoC client ID that is the same as the PoC client ID included in the transmission request message among the session control information stored in the PoC box 30.

The second control unit 74 of the PoC box 30 controls the second communication interface unit 62 to transmit the corresponding media data to the PoC client (step S154: NO), if the session control information having the same PoC client ID does not exist (S156). &Lt; / RTI >

If there is session control information having the same PoC client ID (S154: YES), the second control unit 74 determines whether the corresponding media data is converted into stream data (S158). Since the session control information includes information on the media data or the stream data corresponding to the session control information, the second control unit 74 converts the media data corresponding to the session control information into stream data Can be found.

If the corresponding media data is not the stream data (S158: NO), the media data is transmitted to the PoC client 10 (S160). If the corresponding media data is converted into the stream data (S158: YES), the second communication interface unit 62 of the PoC box 30 transmits the stream data by the RTP method (S162).

When receiving the stream data from the PoC box 30, the PoC client 10 plays back the received stream data in real time (S164).

FIG. 6A is a diagram illustrating a data storage unit according to an embodiment of the present invention, and FIG. 6B is a diagram illustrating stream data according to an embodiment of the present invention.

6A is a block diagram showing an approximate structure of the data storage unit 68. As shown in FIG. The data storage unit 68 includes a session information storage unit 70 and a stream data storage unit 72. The session information storage unit 70 stores session control information corresponding to media data or stream data. The stream data storage unit 72 stores media data or stream data.

6A shows a data storage unit 68 in which session control information and stream data or media data are stored correspondingly. Session control information 1 and session control information 2 are stored in the session information storage unit 70 and stream data 1 and media data 2 corresponding to the session control information 1 and 2 are stored in the stream data storage unit 72 have.

6B shows an example of stream data transmitted from the PoC box 30 to the PoC client 10. As shown in FIG. The PoC box 30 can transmit the session control information and the stream data to the PoC client 10 sequentially. The PoC box 30 may transmit the session control information so that the PoC client 10 can notify that the media data transmitted by the PoC client 10 has been converted into the stream data. The PoC client 10 also uses the session control information to store various information on the stream data transmitted from the PoC box 30, for example, the total number of the media packets constituting the stream data, the RTSP Time information, storage location where each media packet is stored, and the like.

6B shows a first packet, a second packet and a third packet, which are media packets corresponding to each session control information, together with session control information. The first packet includes the first audio data and the first RTSP time information, the second packet includes the second video data and the second RTSP time information, and the third packet includes the third video data and the third RTSP time information . In this manner, each media packet constituting the stream data can have RTSP time information.

7 is a flowchart illustrating a method of processing media data by a PoC box according to another embodiment of the present invention.

In the present embodiment, a case where the PoC box 30 receives media data from the PoC server 20, converts the media data into stream data, and stores the converted stream data in another storage device 80 will be described.

The PoC box 30 receives the media data from the PoC server 20 and converts it into stream data (S172). The PoC box 30 transmits the converted stream data to the predetermined storage device 80. [ The storage device 80 stores the stream data transmitted from the PoC box 30 (S176). The storage device 80 informs the PoC box 30 of the storage location of the stream data (S178). The PoC box 30 generates and stores session control information including a stream storage location (S180).

When the PoC client 10 requests the media data to be transmitted (S182), the PoC box 30 determines the storage location of the stream data using the session control information (S184). Since the session control information corresponding to each stream data includes the storage location of the stream data, the PoC box 30 can inform the PoC client 10 of the storage location of the stream data using the session control information.

The PoC box 30 notifies the PoC client 10 of the storage location of the stream data (S186). The PoC client 188 accesses the storage device 80 in which the stream data is stored, and requests that the stream data be transmitted (S188). The storage device 80 transmits the stream data to the PoC client (S190).

FIG. 1 illustrates a PoC system according to an embodiment of the present invention; FIG.

FIG. 2 is a flowchart illustrating a method of processing media data in a PoC system according to an embodiment of the present invention. FIG.

3 is a block diagram illustrating a schematic configuration of a PoC client and a PoC box in a PoC system according to an embodiment of the present invention;

4 is a flowchart illustrating a method of processing media data by a PoC box according to an embodiment of the present invention;

FIG. 5 is a flowchart illustrating a method of processing media data by a PoC box in a PoC system according to an embodiment of the present invention; FIG.

FIG. 6A illustrates a data storage unit according to an embodiment of the present invention. FIG.

FIG. 6B shows stream data according to an embodiment of the present invention, and FIG.

Claims

A method for processing media data in a PoC box in a PoC system including a PoC (Push-to-talk Over Cellular) server and a PoC box connected to the PoC server,

Receiving media data from a PoC server and temporarily storing the media data;

Converting the temporarily stored media data into stream data that can be transmitted in a streaming manner capable of real-time playback;

Generating session control information for the converted stream data;

And storing the converted stream data and session control information.

The method of claim 1, wherein the step of converting the media data into stream data comprises:

Dividing the received media data by a packet;

Generating RTSP (Real Time Streaming Protocol) time information corresponding to each of the media data divided by the packet;

And adding and storing the generated RTSP time information to the media data of the packet unit.

The method according to claim 1,

Further comprising the step of determining whether the received media data is data that can be transmitted in a streaming manner,

And converting the media data into the stream data only when the media data is data that can be transmitted in the streaming manner.

The method of claim 3,

Generating session control information for the media data when the media data is not data that can be transmitted in the streaming manner;

And storing the media data and the session control information.

5. The method according to claim 1 or 4,

A PoC client ID (ID) of the received media data,

Wherein the PoC client ID is an ID of a receiving PoC client to receive the media data.

The method of claim 3, wherein the step of determining whether the media data is data that can be transmitted in a streaming manner comprises:

Determining whether the media data has a running time,

And determining the media data as data that can be transmitted in a streaming manner when the media data has the playback time.

The method of claim 1, wherein generating the session control information for the transformed stream data comprises:

Generating session control information including a PoC client ID for the media data;

And storing the generated session control information in association with the media data.

6. The method of claim 5,

Receiving a request for transmission of media data from a PoC client;

Determining whether there is session control information including a same PoC client ID as the PoC client ID included in the transmission request;

When the session control information exists, determining whether the media data received by the transmission request is converted into stream data and stored using the session control information;

And transmitting the transformed and stored stream data to the PoC client through a Real Time Transport Protocol (RTP) when the transformed and stored stream data is the transformed and stored stream data.

9. The method of claim 8,

And transmitting the media data corresponding to the session control information to the PoC client when the converted stream data is not the converted stream data.

A PoC box for processing media data together with a PoC server in a Push-to-talk Over Cellular (PoC) system,

A data conversion unit for converting the media data received from the PoC server into stream data that can be transmitted in a streaming manner capable of real-

A session information generator for generating session control information for the converted stream data;

And a data storage unit for storing the converted stream data and session control information.

The data conversion apparatus according to claim 10,

(RTSP) time information corresponding to the media data divided by the packet unit, and transmits the generated RTSP time information to the media data of the packet unit And the media data is converted into the stream data by adding them to the stream data.

11. The method of claim 10,

And a control unit for controlling the data conversion unit to convert the media data into the stream data if the received media data is data that can be transmitted in a streaming manner, PoC box with.

13. The apparatus according to claim 12,

Wherein the session control unit controls the session information generating unit to generate session control information for the media data when the media data is not data that can be transmitted in the streaming manner.

The method as claimed in claim 10 or 13,

A PoC client ID (ID) of the received media data,

13. The apparatus according to claim 12,

When the media data has a playback time, determines the media data as data transmittable by the streaming method.

11. The method of claim 10,

And a PoC client ID (ID) of the media data.

13. The method of claim 12,

Further comprising a communication interface unit for receiving a request for transmission of media data from a PoC client,

Wherein the control unit determines whether the media data received by the transmission request is converted into stream data and stored, using the stored session control information, and if the converted and stored stream data is a stream data, And controls the communication interface unit to transmit the PoC client to the PoC client through a transmission protocol.

18. The apparatus of claim 17, wherein the control unit

And controls the communication interface unit to transmit media data corresponding to the session control information to the PoC client when the stream data is not the converted and stored stream data.

11. The apparatus of claim 10,

A stream data storage unit for storing the converted stream data;

And a session information storage unit for storing the session control information.

18. The apparatus of claim 17,

Upon receipt of the request for transmission of the media data from the PoC client, it is determined whether there exists session control information having the same PoC client ID as the PoC client ID included in the received media data, And controls the communication interface unit to transmit the stream data or the media data to the PoC client.