KR20090126734A - Multimedia messaging service method for voip terminals - Google Patents

Abstract

PURPOSE: An image mailbox service method for a VoIP terminal is provided to provide the audio/video data of a mailbox message by the RTP unit packet. CONSTITUTION: A call connection is tried from an originating VoIP terminal to a receiving VoIP terminal(S100). If the receiving VoIP terminal is busy or absence, a mailbox usage guide message is transmitted to the originating VoIP terminal(S200). The timestamp information included in an RTP packet of the audio/video data of the transmitted mailbox message is corrected to the RTP packet receiving time reference. The corrected information is stored in a mailbox DB(S400). A receiving guide message is transmitted to the receiving VoIP terminal. The audio/video data of the stored mailbox message is transmitted to the receiving VoIP terminal by the RTP unit packet(S700).

Description

Video mailbox service method for mobile terminal {Multimedia messaging service method for VoIP terminals}

The present invention relates to a video mailbox service method for a VoIP terminal, and more particularly, to receive audio data and video data of a mailbox message in a continuous RTP packet unit from an originating VoIP terminal, and timestamp information of each received RTP packet. Is stored based on the time when the packet is actually received, and the audio and video data of the mailbox message stored to the destination VoIP terminal are synchronized and transmitted using the time stamp information of the RTP packet, respectively. It is configured to receive the timely transmission of the RTP packet, and to play the transmitted message based on the corrected time stamp, thereby enabling the video mailbox service to effectively implement audio / video synchronization of mailbox messages regardless of the type of originating VoIP terminal. How about .

Voice over Internet Protocol (VoIP) is a communication technology that delivers voice information using the Internet Protocol (IP) .It uses the existing internet network to transmit voice data in the form of data packets over the Internet protocol. They can receive long distance and international phone service in the Internet and intranet environment with only local call charges, and they can exchange various multimedia information such as video and photos in addition to voice.

The VoIP telephone service provides voice communication between various VoIP terminals (for example, ordinary computer terminals equipped with VoIP applications and interfaces or Internet phones made exclusively for VoIP services) connected to each other through an Internet network. A gateway connected to a public switched telephone network (PSTN) or a mobile communication network allows a VoIP terminal to communicate with other types of communication devices such as landline phones and mobile communication terminals.

The VoIP telephone service provides a variety of services to VoIP terminal users by utilizing the characteristics of transmitting video and voice at the same time. Among them, the calling terminal user records a video message when the called terminal user is busy or absent. Thereafter, there is a video mailbox service that allows a user of a called terminal to check recorded video messages.

In the conventional video mailbox service, video and audio data are divided into RTP packet units using RTP (Real Time Protocol) to transmit and receive video messages to and from the VoIP terminal. In the incoming VoIP terminal, the video recorded by the caller is recorded. The video message is reproduced by outputting video and audio data stored in a series of RTP packets in a correct time zone using timestamp information included in the RTP packet of the message.

However, since the time stamp information of the RTP packet transmitted from the VoIP terminal is interpreted differently for each terminal manufacturer, the process of playing a video message recorded by the receiving VoIP terminal when the originating VoIP terminal and the destination VoIP terminal are different. Audio / video synchronization (syncronization) does not fit correctly, there is a problem that causes the user inconvenience.

In addition, a server providing a conventional multimedia ringback service is typically configured based on LINUX or SOLARIS rather than a real-time OS (RTOS), and cannot accurately control a transmission interval between Real-time Transport Protocol (RTP) packets to 10 ms or less. Therefore, in the process of transmitting a video message in units of RTP packets for audio and video, errors in the transmission time interval of each RTP packet accumulate, which may cause an audio / video synchronization problem when a message is played on an incoming VoIP terminal. have.

The present invention is to solve the problem of the multimedia ringback service according to the prior art. That is, an object of the present invention is to receive audio data and video data of a mailbox message in a continuous RTP packet unit from an originating VoIP terminal, and timestamp information of each received RTP packet based on the time at which the packet is actually received. By calibrating and storing the received mailbox message in RTP packet unit, the stored mailbox message is reproduced based on the corrected time stamp, which effectively implements audio / video synchronization of mailbox message regardless of the type of originating VoIP terminal. Its purpose is to.

In addition, the present invention by synchronizing the audio and video data of the stored mailbox message based on the timestamp information of the RTP packet, respectively, and transmits the audio and video data of the mailbox message recorded in the recipient VoIP terminal to the RTP packet. Another purpose is to allow timely transmission in units of time so that audio / video synchronization can be reproduced correctly.

The present invention as a technical concept for achieving the above object, when the call connection attempt from the originating VoIP terminal to the destination VoIP terminal, if the destination VoIP terminal is busy or absent, transmitting a mailbox use guide message to the calling VoIP terminal side; Wow; When the originating VoIP terminal transmits the mailbox message in response to the transmitted message, the time stamp information included in the RTP packet of the audio and video data of the transmitted mailbox message is corrected based on the time when the corresponding RTP packet is received. Recording a mailbox message stored in the mailbox DB; When a guide message for notifying the reception of a mailbox message is transmitted to a destination VoIP terminal, and a request for a mailbox message is transmitted from the destination VoIP terminal in response to the transmitted guidance message, audio and video data of the stored mailbox message are stored in RTP packet units, respectively. Transmitting the mailbox message to the destination VoIP terminal, wherein the transmitting of the mailbox message includes a theoretical time required from the time of transmission of the first RTP packet by using the corrected timestamp information of the RTP packet to be transmitted. The present invention provides a video mailbox service method for a VoIP terminal, comprising: calculating, performing a sleep by a difference between the actual time required and the calculated theoretical time required, and then transmitting an RTP packet to be transmitted.

In the video mailbox service method for a VoIP terminal according to the present invention, the incoming VoIP terminal can receive audio and video data of a mailbox message in RTP packet units in a timely manner, and at the same time, each RTP packet is actually received from an originating VoIP terminal. Since it can be played back as a reference, it is possible to provide a high quality video mailbox service in which audio / video of a mailbox message is synchronized regardless of the type of originating VoIP terminal.

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

1 is a configuration diagram of a video mailbox system to which a video mailbox service method according to the present invention is applied.

As shown in FIG. 1, a video mailbox system to which a video mailbox service method according to the present invention is applied receives video mailbox messages divided into audio data and video data from an outgoing VoIP terminal 600, and stores previously stored video mailbox messages. A message communication unit 400 for synchronizing audio data and video data with each other and transmitting them to the incoming VoIP terminal 700, and a call processing unit 500 for relaying a call between the outgoing VoIP terminal 600 and the incoming VoIP terminal 700; In accordance with the control message of the call processing unit 500, the mailbox management unit 100 for recording or sending a mailbox message by controlling the message communication unit 400, and the mailbox transmitted from the originating VoIP terminal 600 through the message communication unit 400 It is configured to include a mailbox DB (200) for storing messages.

The message communication unit 400 sequentially receives the video RTP packet of the video mailbox message from the originating VoIP terminal 600, corrects the timestamp information in the RTP packet based on the actual transmission time, and sends it to the called VoIP terminal 700. The video processor 410 transmits the video data of the recorded video mailbox message by synchronizing the RTP packet based on the time stamp information in each RTP packet, and the audio RTP packet of the video mailbox message from the originating VoIP terminal 600 in sequence. The received VoIP terminal 700 corrects the time stamp information in the RTP packet based on the actual transmission time, and synchronizes the RTP packet based on the time stamp information in each RTP packet with the audio data of the recorded video mailbox message. It consists of an audio processor 420 to transmit to. Here, a process of correcting the structure of the RTP packet and the time stamp in the RTP packet transmitted from the originating VoIP terminal and synchronizing the transmitted time stamp based on the corrected time stamp at the time of transmitting the RTP packet to the transmitting VoIP terminal will be described in detail later. Shall be.

The mailbox manager 100 divides the video data and the audio data of the mailbox message transmitted from the originating VoIP terminal 600 through the message communication unit 400 into video files and audio files, respectively, and stores them in the mailbox DB 200. When there is a request for transmitting a mailbox message from the processing unit 500 to the receiving VoIP terminal 700, the receiving VoIP terminal reads the video file and the audio file of the previously stored mailbox message from the mailbox DB 200 and delivers it to the message communication unit 400. The mailbox message is sent to the (700) side.

The call processing unit 500 transmits and receives a Session Initiation Protocol (SIP) message for call connection with the outgoing VoIP terminal 600 and the incoming VoIP terminal 700, and relays the call connection to the mailbox management unit 100. The control message is transmitted to record the mailbox message transmitted from the originating VoIP terminal 600 or to transmit the recorded mailbox message to the destination VoIP terminal 700.

2 is a flowchart illustrating a video mailbox service procedure according to an embodiment of the present invention.

Hereinafter, a video mailbox service method according to an embodiment of the present invention using the video mailbox service system described above will be described with reference to FIG. 2.

First, when there is a call connection attempt from the outgoing VoIP terminal 600 to the incoming VoIP terminal 700 (S100), the call processing unit 500 is in the absence state that the incoming VoIP terminal 700 is busy or there is no call response for a predetermined time. If the call is not in a busy or missed state, the call connection between the outgoing VoIP terminal 600 and the incoming VoIP terminal 700 is relayed (S900), and the incoming VoIP terminal 700 is busy or out of call. The VoIP terminal 600 notifies the fact that it is busy or absent and simultaneously transmits a mailbox use guide message (S200).

When the originating VoIP terminal 600 transmits a mailbox message according to the transmitted mailbox usage guide message (S300), the mailbox management unit 100 continuously transmits the audio data and the video data of the mailbox message from the originating VoIP terminal 600. A mailbox message is recorded by storing the audio file and the video file received in packet units, correcting the time stamp information of each received RTP packet, and storing a series of RTP packets whose time stamp is corrected (S400). A detailed process of correcting and storing time stamp information of each RTP packet will be described in detail later.

Subsequently, when a guide message for notifying that the mailbox message has been received is transmitted to the incoming VoIP terminal 700 (S500), and when the incoming VoIP terminal 700 requests the transmission of the mailbox message in response to the transmitted guidance message (S600), Video data and audio data of the recorded mailbox message are transmitted to the incoming VoIP terminal 700 in units of RTP packets, respectively (S700).

Finally, the incoming VoIP terminal 700 plays the received mailbox message and outputs it to the user (S800).

3 is a view showing the structure of an audio and video file obtained through the mailbox message receiving and recording step shown in Figure 2, Figure 4 is a flow chart showing the detailed procedure of the mailbox message receiving and recording step shown in FIG.

As described above, in the receiving and recording of the mailbox message (S400), the audio data and the video data of the mailbox message are received from the originating VoIP terminal 600 in a continuous RTP packet unit, and time stamp information of each received RTP packet is received. An audio file and a video file, each of which is composed of a series of RTP packets whose time stamps are corrected and stored, are stored. First, a data structure of an audio and video file consisting of RTP packets will be described with reference to FIG. 3.

The audio and video files of the mailbox message, respectively, are composed of one file in succession of several RTP packets, as shown in Fig. 3 (a). Each RTP packet is the originating VoIP terminal 600 or the called party. Corresponds to a transmission unit transmitted at a time when transmitting and receiving a mailbox message with the VoIP terminal 700. The structure of the RTP packet, like the MOD_RTP_PACKET structure shown in (b) of FIG. 3, is mainly composed of an RTP header and an RTP payload, and information for RTP communication is stored in the RTP header. In the RTP payload, audio and video data of the corresponding frame are stored. In this case, a timestamp value indicating the number of clocks for reproducing synchronization of the packet is stored in the RTP header.

Hereinafter, detailed steps of the mailbox message receiving and recording step S400 will be described with reference to FIG. 4.

First, the message communication unit 400 receives the first RTP packet from the originating VoIP terminal 600 (S410), and temporarily stores the received first RTP packet and the time at which the packet is received in the memory (S420).

Subsequently, the next RTP packet is received from the originating VoIP terminal 600 (S430), and the timestamp value of the currently received RTP packet is calculated from the difference between the current time and the reception time of the first RTP packet (S440). Here, the timestamp value of the currently received RTP packet is obtained by converting the time elapsed from receiving the first RTP packet to receiving the current RTP packet into a timestamp according to the codec standard of the RTP packet. (tp) is calculated using Equation 1 below.

tp = tp ₀ + (tp _frame × t _inc ) / t _frame

Where tp ₀ is the timestamp value of the first RTP packet, tp _frame is the timestamp value that increases per frame, t _inc is the time elapsed from the time of receiving the first RTP packet to the time of receiving the current RTP packet, and t _frame is This is the time transmitted per frame.

For example, referring to Table 1 below, a process of calculating a time stamp for each RTP packet using Equation 1 is as follows.

No. The time at which the RTP packet was received Elapsed time since first RTP packet received Timestamp One 2:30:10 000 0 ms 240 2 2: 30: 10: 020 20 ms 400 3 2:30 10 seconds 050 50 ms 640

If the codec applied to RTP transmission is G.723.1, the time transmitted per _frame (t _frame ) is 30 ms, and the time stamp value (tp _frame ) increases per _frame is designated as 240 ms. The time stamp tp ₀ can be set to any value. In this example, it is assumed to be 240.

When the second RTP packet is received, since the time elapsed from the time of receiving the first RTP packet is 20 ms, the time stamp of the packet is calculated as 400 corresponding to (240 + (240 × 20) / 30) from Equation 1 above. do.

As described above, the present invention applies the time stamp corrected based on the time when the corresponding packet is actually received for all the RTP packets, so that the incoming VoIP terminal 700 according to a certain criterion regardless of the type of the originating VoIP terminal. The audio and video data of the mailbox message can be played frame by frame based on the assigned time stamp.

When the timestamp numerical calculation step S440 is completed as described above, the timestamp of the currently received RTP packet is changed to the calculated timestamp and temporarily stored in the memory (S450).

Thereafter, the message communication unit 400 checks whether a message indicating that the recording of the outgoing VoIP terminal 600 has been received from the call processing unit 500 determines whether or not to terminate the recording (S460). Returning to the step of receiving the next RTP packet (S430) and repeatedly performing the following steps, and when the recording is terminated by transmitting the RTP packets sequentially stored in the memory to the mailbox management unit 100, the mailbox management unit 100 In step S470 to store the mailbox message file consisting of a series of RTP packets in the mailbox DB (200).

Steps S410 to S470 described above are independently performed on audio data and video data of a mailbox message transmitted from the originating VoIP terminal 600. Finally, in step S470, audio RTP packets whose time stamp values are corrected Similarly, an audio file consisting of a video file consisting of video RTP packets whose timestamp value is corrected is stored, respectively.

5 is a flowchart showing the detailed procedure of the step of transmitting a mailbox message to the destination VoIP terminal shown in FIG.

If the mailbox service system to which the present invention is applied is configured based on LINUX or SOLARIS rather than real-time OS (RTOS), the transmission interval between Real-time Transport Protocol (RTP) packets cannot be accurately controlled to 10 ms or less. In the process of streaming audio and video data, a problem may occur in that synchronization of audio / video is not exactly matched due to an error in transmission time intervals accumulated while sequentially transmitting packets.

Therefore, in this embodiment, the theoretical time is calculated by using the time stamp information included in each RTP packet, and then the audio / video synchronization problem is solved by performing a slip so that the actual time matches the theoretical time. A detailed process of performing the mailbox message transmission step S700 to the VoIP terminal shown in FIG. 2 using the sleep algorithm as described above will be described with reference to FIG. 5.

First, the message communication unit 400 reads an audio and video file of a mailbox message to be transmitted from the mailbox DB 200 and temporarily stores the audio and video file in the memory (S710).

Thereafter, the read audio and video files are independently RTP-transmitted to the destination VoIP terminal 700, and the audio transmission step and the video transmission step are commonly performed as follows.

First, the first RTP packet is read from the memory and transmitted to the incoming VoIP terminal 700 (S720), and the timestamp and transmission start time of the first RTP packet are stored (S730).

Thereafter, the next RTP packet to be transmitted is read from the memory (S740), and a sleep time is calculated (S750). Here, the theoretical time required from the time of transmission of the first RTP packet is first calculated by using the difference between the timestamp of the RTP packet to be transmitted and the timestamp of the first RTP packet, and the actual time, i.e., the current time and the first RTP packet, The difference between the transmission start time is calculated, and the sleep time is set as much as the difference between the theoretical time and the actual time.

Subsequently, sleep is performed for the set sleep time (S760), and the RTP packet to be transmitted is transmitted (S770). By performing the sleep as described above, the actual time required to transmit the corresponding RTP packet is adjusted to be equal to the theoretical time required to implement audio / video synchronization.

Thereafter, it is determined whether there is a transmission stop request from the call processing unit 500 (S780). If there is a transmission stop request, the RTP transmission is stopped and the transmission process is completed. It is determined whether it is the last packet (S790).

In step S790, if it is determined that the packet is the last packet, the RTP transmission is stopped and the transmission process is completed. If it is determined that the packet is not the last packet, the next step is to read the next RTP packet to be transmitted (S740). Branches to and repeats the steps below.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

1 is a configuration diagram of a video mailbox system to which a video mailbox service method according to the present invention is applied.

2 is a flowchart illustrating a video mailbox service procedure according to an embodiment of the present invention.

3 is a view showing the structure of an audio and video file obtained through the receiving and recording of a mailbox message shown in FIG.

FIG. 4 is a flow chart showing the detailed procedure of the mailbox message receiving and recording step shown in FIG.

Fig. 5 is a flowchart showing the detailed procedure of the step of transmitting a mailbox message to the destination VoIP terminal shown in Fig. 2;

<Explanation of symbols for the main parts of the drawings>

100: mailbox management unit 200: mailbox DB

400: message communication unit 410: video processing unit

420: audio processing unit 500: call processing unit

600: outgoing VoIP terminal 700: incoming VoIP terminal

Claims (5)

Transmitting a mailbox usage guide message to the calling VoIP terminal when the called VoIP terminal is busy or absent when attempting to connect a call from the calling VoIP terminal to the called VoIP terminal; When the originating VoIP terminal transmits a mailbox message in response to the transmitted mailbox usage guide message, the time stamp information included in the RTP packet of the audio and video data of the transmitted mailbox message is based on the time when the corresponding RTP packet is received. A mailbox message recording step of correcting and storing in the mailbox DB; When the receiving VoIP terminal transmits a reception guide message notifying the reception of a mailbox message and the receiving VoIP terminal requests the transmission of the mailbox message in response to the received reception guide message, audio and video data of the stored mailbox message are respectively RTP packets. Transmitting the mailbox message to the destination VoIP terminal in units; It is configured to include, The mailbox message transmission step, The theoretical time is calculated from the time of transmission of the first RTP packet by using the corrected time stamp information of the RTP packet to be transmitted, and sleep is performed by the difference between the actual time and the calculated theoretical time. And a post office RTP packet. The method of claim 1, The mailbox message recording step, Receiving a first RTP packet from an originating VoIP terminal, and temporarily storing the received first RTP packet and a reception time in a memory; A timestamp calculating step of receiving a next RTP packet from an originating VoIP terminal and calculating a timestamp value of the currently received RTP packet from the difference between the current time and the reception time of the first RTP packet; Changing a timestamp of a currently received RTP packet to the calculated timestamp and temporarily storing it in a memory; Determining whether to end recording by checking whether a message indicating that recording of the originating VoIP terminal has ended is received, and when the recording is finished, storing a mailbox message file consisting of RTP packets sequentially stored in a memory in a mailbox DB; Video mailbox service method for a VoIP terminal, characterized in that consisting of. The method of claim 2, In the time stamp calculation step, A VoIP terminal comprising calculating a timestamp value of a currently received RTP packet by converting a time elapsed from receiving a first RTP packet to a current RTP packet to a timestamp according to the codec specification of the RTP packet. How to service video mailboxes. The method of claim 1, The mailbox message transmission step, Reading audio and video files of a mailbox message to be transmitted from a mailbox DB and temporarily storing the same in a memory; An audio transmission step of RTP transmission of the audio file of the read mailbox message to a destination VoIP terminal; A video transmission step of RTP transmission of the video file of the read mailbox message to a destination VoIP terminal; Consists of, And the audio transmission step and the video transmission step are performed independently of each other. The method of claim 4, wherein The audio transmission step and the video transmission step, respectively, Reading the first RTP packet from the memory and transmitting the first RTP packet to the destination VoIP terminal, storing the timestamp and transmission start time of the first RTP packet; The next RTP packet to be transmitted is read from the memory, and the theoretical time is calculated from the difference between the timestamp of the RTP packet to be transmitted and the timestamp of the first RTP packet, and the actual time is calculated from the difference between the current time and the transmission start time of the first RTP packet. Calculating a time required to calculate a slip time by the difference between the theoretical time required and the actual time required; Transmitting an RTP packet which is a transmission target after performing sleep for the calculated sleep time; Video mailbox service method for a VoIP terminal, characterized in that consisting of.

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