KR100889873B1 - Method and apparatus for mesuring quality of video call - Google Patents

Abstract

The present invention relates to a method and apparatus for measuring a call quality of a video call, comprising the steps of: measuring a call quality of a video call between a calling video terminal and a called video terminal; Setting a substitute video to be transmitted to the calling video terminal when a call is established; Forming a video call between the calling video terminal and the called video terminal; Playing, by the called video terminal, the set replacement video and transmitting the set replacement video to the calling video terminal through the video call; Receiving, by the calling video terminal, a substitute video transmitted from the called video terminal and transmitting the received replacement video to a calling video call quality measuring device; And comparing a substitute video transmitted from the calling video terminal with a comparison video previously stored as a reference video for measuring call quality by a calling video call quality measuring device. .

Video call calls, video call quality measurements

Description

METHOD AND APPARATUS FOR MESURING QUALITY OF VIDEO CALL}

1 is a diagram illustrating a concept of a method for measuring call quality of a video call;

2 is a view for explaining a method for measuring call quality using a conventional WCDMA wireless data modem;

3 is a view for explaining a method of using a conventional reference image server;

4 is a view showing a connection relationship between a video call quality measuring apparatus, a mobile communication network and a video terminal for performing a call quality measuring method of a video call according to an embodiment of the present invention;

5 is a flowchart illustrating a method of measuring video call quality according to an embodiment of the present invention;

6 is a block diagram showing an internal configuration of a video call quality measurement apparatus.

<Description of Signs of Major Parts of Drawings>

10 ... the calling video terminal,

20. Calling party video quality measurement device,

30.

40. called party video terminal,

50 ... Video call quality measurement device at the called party.

The present invention relates to a method and apparatus for measuring a call quality of a video call, and to a method and apparatus for measuring a video call quality felt by an actual user on a mobile communication network supporting a video call.

One of the most characteristic services of the third generation mobile communication system is a video call service. Therefore, video call quality in 3G mobile communication systems has become an important factor in determining the success or failure of 3G mobile communication services, and the technology and method for measuring video call quality that subscribers can actually experience are also very important. It is becoming.

In order to measure video call quality, a video call is set up between video terminals, and when a video call is set, a reference video necessary for measuring video call quality is transmitted to the other party, as shown in FIG. 1. Call quality measurement parameters such as video MOS (Mean Opinion Score), PNSR, Blur, Blockiness, Jerkiness should be measured by comparing algorithms.

On the other hand, in order to measure the haptic video call quality that can be experienced by the actual user, first of all, the video call quality should be measured by using a real commercial video terminal, not a measuring device. However, unless the video terminal is modified for the purpose of measuring the call quality, there is no method of transmitting a reference video to the opposite video call quality meter through the actual commercial video terminal from the external measuring device. The most common method is to use modem and reference video server.

2 is a view for explaining a method for measuring the call quality using a conventional WCDMA wireless data modem.

Referring to FIG. 2, instead of using an actual video terminal for video call quality measurement, a WCDMA wireless data modem, for example, a PCMCIA type, is embedded in a video quality measurer (or PC), and H. A video telephony emulator that implements the 324M protocol and video codec in software. Next, after the video telephony emulator on the calling video quality meter is connected via the WCDMA wireless data modem via the called video quality meter and the wireless data modem, H. H. on the 64 kbps bearer channel between the two video telephony emulators. After the 324M video call is connected, the reference video call emulator transmits the reference video to the calling video call quality meter, and compares the reference video received from the receiving video call quality meter with the previously compared comparison video. It is a method of measuring video call quality. However, in this case, since the communication path is different from the actual video call, and unlike the real video terminal, the video telephony emulator on the measuring device is used. There is a problem that does not reflect the quality of experience.

3 is a view for explaining a method of using a conventional reference image server. Referring to FIG. 3, in order to solve the drawback that an external video call quality meter cannot transmit a reference video through an actual video terminal, a reference video server connected to an exchange instead of the called video terminal is connected to an H.324M video phone. Receiving and transmitting a reference video set to the calling video terminal. The reference video server is connected to the core network via H.324M / E1 and uses the H.324M protocol and DSP-based codec on the video IVR board to receive video call calls. However, even in this case, the video call communication path is connected to the video call path, but since one side is a server rather than a video terminal, the codec characteristics and quality are different from those of the actual video terminal and do not reflect one wireless environment. Has a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to provide a method and apparatus for measuring a video call quality experienced by a real user on a mobile communication network supporting a video call.

In addition, the present invention can use the actual video call path on the mobile communication network as it is without modifying the commercial video terminal used by the user as it is, it is possible to easily and accurately measure the user's haptic video call quality It is another object to provide a method and apparatus.

In order to achieve the above object, the present invention provides a method for measuring the call quality of a video call call between the calling video terminal and the called video terminal, the video call call is formed with the calling video terminal in the called video terminal; Setting a substitute video to be transmitted to the calling video terminal, if available; Forming a video call between the calling video terminal and the called video terminal; Playing, by the called video terminal, the set replacement video and transmitting the set replacement video to the calling video terminal through the video call; Receiving, by the calling video terminal, a substitute video transmitted from the called video terminal and transmitting the received replacement video to a calling video call quality measuring device; And comparing a substitute video transmitted from the calling video terminal with a comparison video previously stored as a reference video for measuring call quality by a calling video call quality measuring device. .

Here, the comparison image and the replacement image are preferably the same.

In addition, when the video connection call with the calling video terminal is established in the called video terminal, setting an alternative video to be transmitted to the calling video terminal is stored in the called video call quality meter connected to the called video terminal. The reference image may be configured to be transmitted to the called party's video terminal, and the reference picture may be set as a substitute image of the called party's video terminal.

In addition, the step of forming a video call call between the calling video terminal and the called video terminal, the calling video call quality measuring device connected to the calling video terminal to the calling video terminal to the called video terminal. Transmits a signal requesting to transmit a call call connection request signal, and the calling video terminal transmits a video call call connection request signal to the called video terminal according to the signal, and in response, a video call from the called video terminal. It can be configured to be formed by receiving a call connection response signal.

In addition, the step of playing the replacement video in the called video terminal and transmitting to the calling video terminal via the video call, the called video terminal in the called video call quality meter connected to the called video terminal. When a signal indicating to play the replacement video is transmitted, the called video terminal may be configured to play the replacement video.

The comparing of the substitute video transmitted from the calling video terminal by the calling video call quality measuring instrument with the comparison video stored as a reference video for measuring call quality is transmitted from the calling video terminal. Detecting a sync frame included in the replacement image; Storing a substitute image of a predetermined length from the sync frame; The method may include comparing the stored comparison image of the length corresponding to the replacement image of the predetermined length with the stored replacement image of the predetermined length as a reference image.

According to another aspect of the present invention, in the video call call quality measurement apparatus for measuring the call quality of the video call call between the calling video terminal and the called video terminal, the calling video terminal, An input / output port connected to transmit and receive control signals and data; An alternative video storage for storing an alternative video transmitted by the calling video terminal, wherein the alternative video is received and transmitted from the called video terminal when the calling video terminal forms a video call with the called video terminal; A comparison image storage unit which stores a comparison image to be compared with a replacement image transmitted from the calling image terminal; An image comparison unit comparing the replacement image stored in the replacement image storage unit with a comparison image stored in the comparison image storage unit as a reference image for measuring call quality; And a controller for controlling the operations of the input / output port, the substitute video storage, the comparison video storage, and the video comparator.

Here, the comparison image and the replacement image are preferably the same.

The substitute video transmitted from the called video terminal to the calling video terminal transmits the reference video stored in the called video call quality meter connected to the called video terminal to the called video terminal. The video may be configured as an alternative video of the called video terminal.

The substitute image storage unit detects a sync frame included in the substitute image transmitted from the calling video terminal, stores a substitute image having a predetermined length from the sync frame, and the image comparison unit stores the stored predetermined length. It is preferable to compare the comparison amount of the length corresponding to the replacement image of the predetermined length as a reference image for measuring the call quality of the replacement image of the amount.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is described in detail with reference to an accompanying drawing.

4 is a diagram schematically illustrating a connection relationship between a video call quality measuring apparatus, a mobile communication network, and a video terminal for performing a call quality measuring method of a video call according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the video call quality measurement apparatuses 10 and 50 of the video call call of the present embodiment are connected to the calling video terminal 20 and the called video terminal 40, respectively. Hereinafter, the caller is connected to the calling party video terminal 20 by the caller video call quality measuring apparatus 10, and the caller is connected to the called party video terminal 40 by the called party video call quality measuring apparatus 50. do. However, the distinction between the calling party and the called party is only a difference depending on which one is connected to the calling party or the called party video terminal, and the physical configurations of the two video call quality measuring apparatuses 10 and 50 are the same.

The caller video call quality measuring apparatus 10 is connected to the caller video terminal 20 to control the caller video terminal 20 so as to connect the caller with the caller video terminal 40 and the video call call. When it is formed, it receives the reference video transmitted from the called party video terminal 40 through the mobile communication network 30 through the calling video terminal 20 and compares it with the comparison video to measure the quality of the video call. Perform.

The called party's video call quality measuring device 50 is connected to the called party's video terminal 40 to control the called party's video terminal 40 so as to connect the video call with the calling party's video terminal 20, and the video call is formed. In this case, the called party video terminal 40 controls to transmit the reference video to the calling video terminal 20 through the mobile communication network 30. In addition, the called-party video call quality measuring device 50 has a function of setting a reference video of the called-party video terminal 40. Here, the reference video transmitted from the called video terminal 40 to the calling video terminal 20 uses an alternative video provided instead of the video screen when the user does not use the video call function during the video call. Let the dot be one of the main features. A detailed method of using such a substitute image as a reference image will be described later with reference to FIG. 5.

Meanwhile, the calling video terminal 20 and the called video terminal 40 mean a general commercial video terminal having a function of performing a video call. The calling video terminal 20 is connected to the calling video call quality measuring apparatus 10 and connects the called video terminal 40 to the video calling call according to the control instruction of the device 10. The reference image transmitted from the called party video terminal 40 is received and streamed to the calling video call quality measurement apparatus 10 in real time. Meanwhile, the called party video terminal 40 is connected to the called party video call quality measuring device 50 to connect the calling video terminal 20 with a video call call under the control of the device 50 and to measure the call quality. The reference image is transmitted to the calling video terminal 20 through the mobile communication network 30.

The mobile communication network 30 refers to a mobile communication environment such as a WCDMA system that supports video calls, and includes a mobile switching center (MSC), a home location register (HLR), and a visitor location register. , VLR) means a backbone network that controls subscriber's location registration, call connection control, and billing processing. On the other hand, the base station is a wireless channel management, terminal protocol matching, base station protocol matching and control in a specific area where the video terminal 20, 40 is located between the mobile communication network 30 and the source and destination video terminal (20, 40) It is a system for configuring a Radio Access Network (RAN) such as call processing, soft handoff processing, and the like. The mobile communication network 30 and the base station mean a whole network supporting video telephony as a component other than a video terminal, and the present invention may be applied as long as it is a network of all kinds supporting video telephony. Since the specific configuration of the mobile communication network 30 is not directly related, detailed description thereof will be omitted.

FIG. 5 is a flowchart illustrating a method of measuring video call quality according to an exemplary embodiment of the present invention in a connected state as shown in FIG. 4.

Referring to FIG. 5, first, the called party's video call quality measurement device 50 connected to the called party's video terminal 40 sets an alternative image of the called party's video terminal 40 (S100). Here, the substitute video refers to an image stored in advance in the video terminal so that the video is reproduced by replacing the video call when the user does not want to perform a video call using an imaging means such as a camera provided in the video terminal. Say. That is, when the video call is connected to the user using the video terminal, this means that the video is pre-determined to replace the video call when the user does not want to perform the video call (that is, the user wants to perform only the voice call). The video terminal basically supports such a function, and the user can set which video to use as a substitute video. The substitute image may use video data stored by the terminal itself, but is used as a reference image for measuring call quality in the calling video terminal 20 and the calling video call quality measuring apparatus 10 as described below. It is preferable that it is an image as sample data capable of sufficiently performing call quality measurement. The called party's video call quality measuring device 50 transmits the sample data image to the called party's video terminal 40 and stores the sample data image in the called party's video terminal 40 as a substitute video to be reproduced in the called party's video terminal 40. Set it. Of course, in this case, the alternative video set should be stored in the calling video call quality measuring apparatus 10 in the same manner.

On the other hand, the replacement video preferably includes a sync frame for allowing the calling video call quality measurement apparatus 10 to set a reference time point for the comparison of the video. The originating video call quality measuring apparatus 10 detects a sync frame in the substitute video and sets it as a reference time point for comparison. The sync frame is preferably composed of a countdown image that can be seen by the real eye that does not lose its information even when compressing the image.

Next, the calling video call quality measurement apparatus 10 sets the phone number of the calling / called video terminal, alternative video information, and the like to the calling video terminal 20 and the video of the called video terminal 40. A signal informing that the call call connection request signal is to be transmitted is transmitted (S110). The calling video terminal 20 transmits a video call call connection request signal to the called video terminal 40 through the mobile communication network 30 according to the signal (S120).

When the called party video terminal 40 receives the video call call connection request signal, the called party video terminal 40 transmits it to the called party video call quality measuring device 50 and the called party video call quality measuring device 50. ) Transmits a signal informing that it will respond (S130). When the signal is received, the called party video terminal 40 responds to the video call call connection request signal to form a video call call with the calling party video terminal 20 (S140), and the calling party video call quality measuring apparatus 10. Recognizes this and enters the ready state for measuring the call quality (S150).

When the video call is made, the called party's video call quality measuring apparatus 50 transmits a signal instructing the called party's video terminal 40 to play back the replacement video preset in step S100 (S160). According to the signal, the called party video terminal 40 reproduces the substitute video and transmits it to the calling party video terminal 20 through the mobile communication network 30 (S170).

When the replacement video is reproduced and transmitted from the called party video terminal 40, the calling party video terminal 20 receives the streaming video and streams it to the calling video call quality measurement apparatus 10 in real time (S180).

The calling video call quality measuring apparatus 10 extracts various parameters for measuring video call quality by comparing the alternative video received from streaming as a reference video previously stored as a reference video for video call quality measurement, and thereby makes a video call. The quality is measured (S190).

In order to compare the replacement video with the comparison video, the calling video call quality measuring apparatus 10 detects a sync frame included in the replacement video as described above, and outputs a predetermined length amount, for example, 4 seconds or 8 seconds, from the sync frame. After storing the replacement image of, it is preferable to compare the comparison image corresponding to this length.

In the step S190, video call quality measurement may use an existing commercial video quality measurement algorithm, and for example, evaluate video call quality by measuring parameters such as video MOS (Mean Opinion Score), PNSR, Blur, Blockiness, Jerkiness, etc. Done. The present invention is not intended to be a direct method of how to measure video call quality, and any conventional video quality measurement algorithm can be used, so a detailed description thereof will be omitted.

On the other hand, in the embodiment of Figure 5, the calling party / called party video call quality measurement apparatus 10, 50 may be connected through the data input / output ports provided in the calling party / called party video terminals (20, 40), respectively. To this end, the calling party and the called party video call quality measurement apparatus 10, 50 is also provided with a port for data input and output. Through the data input / output port, the calling party / called party video call quality measuring apparatus 10 and 50 transmits and receives various control signals and data (alternative video, etc.) to the calling party / called party video terminals 20 and 40. Various control signals and data transmission and reception used at this time may use the function of the terminal itself provided by the terminal manufacturer.

For example, when the calling party and the called party video terminals 20 and 40 use Qualcomm Chipset, the Qualcomm chipset uses a DM (Diagnostic Message) port used for diagnosing the terminal. In order to provide a DM interface for using the DM port, the measurement apparatuses 10 and 50 may transmit and receive various control signals and data using the measurement apparatus 10 and 50. For example, the calling video terminal 20 receives an alternative video transmitted from the called video terminal 40 through the mobile communication network 30 and transmits the replacement video to the calling video call quality measuring apparatus 10 in real time. In step S180, a terminal using a Qualcomm chipset may use a QVP log message. Since the QVP log message outputs all video call contents (H.223U) and control protocol messages (H.245 PDU) transmitted and received by the terminal during a video call, the calling video call quality measuring apparatus 10 After receiving this message in real time through the DM interface, it is possible to decode H.245 call session connection protocol and session control protocol and demultiplex the H, 223 PDU, a video bearer multiplexing protocol, to receive the replacement video in real time. have.

On the other hand, as an example of the method for detecting the above-described sync frame, the following method can be used. That is, for example, the header information of the H.223 multiplexing protocol has a sequence number. By matching the sequence number with the frame number, synchronization between frames can be achieved.

6 is a block diagram illustrating an internal configuration of the calling video call quality measuring apparatus 10 described with reference to FIGS. 4 to 5.

Referring to FIG. 6, the calling video call quality measuring apparatus 10 is connected to the calling video terminal 20, and includes a control unit 11, an input / output port 12, an alternative video storage unit 13, and a comparison. An image storage unit 14 and an image comparator 15 are included.

The control unit 11 controls the operation of the entire apparatus 10 including the input / output port 12, the replacement image storage unit 13, the comparison image storage unit 14, and the image comparison unit 15.

The input / output port 12 is connected to the calling video terminal 20 to transmit and receive control signals and data. As described above, for example, when the terminal 20 uses a Qualcomm chipset, the DM port is provided. It may include a DM interface for.

The replacement video storage unit 13 is a means for storing a replacement video transmitted by the calling video terminal 20. In this case, the substitute video is received from the called video terminal 40 when the calling video terminal 20 forms a video call with the called video terminal 40 and is transmitted in real time.

The comparison image storage unit 14 is a means for storing a comparison image to be compared with the replacement image transmitted from the calling image terminal 20. Here, the comparison image is the same as the replacement image as described above.

Meanwhile, the substitute image storage unit 13 and the comparison image storage unit 14 are means for storing data and are distinguished according to their functions, and may be physically implemented as a single storage device such as a memory or a hard disk. Of course it can.

The image comparison unit 15 is a means for comparing the replacement image stored in the replacement image storage unit 13 with the comparison image stored in the comparison image storage unit 14 as a reference image for measuring call quality.

In order for the image comparison unit 15 to compare the images more easily, the substitute image storage unit 13 detects a sync frame included in the substitute image transmitted from the calling video terminal 20, and selects a predetermined frame from the sync frame. A substitute image of a length of 4 seconds or 8 seconds, for example, and the image comparator 15 stores the stored substitute image of a predetermined length as the reference image for measuring call quality as the reference image for measuring the call quality. It can be compared with a comparison image of the corresponding length amount as described above.

According to the present invention, it is possible to provide a method and apparatus for measuring a video call quality experienced by a real user on a mobile communication network supporting a video call.

In addition, according to the present invention, since the actual video call path on the mobile communication network is used as it is without modifying the commercial video terminal used by the user as it is, it is easy and accurate to measure the user's immersive video call quality. It may provide a method and apparatus that can be.

Claims (10)

In the method for measuring the call quality of a video call call between the calling video terminal and the called video terminal, Setting a substitute video to be transmitted to the calling video terminal when a video call is established with the calling video terminal at the called video terminal; Forming a video call between the calling video terminal and the called video terminal; Playing, by the called video terminal, the set replacement video and transmitting the set replacement video to the calling video terminal through the video call; Receiving, by the calling video terminal, a substitute video transmitted from the called video terminal and transmitting the received replacement video to a calling video call quality measuring device; And Comparing, by the calling video call quality measuring device, with a comparison video previously stored from the calling video terminal and a comparison video stored in advance, wherein the comparing video is transmitted from the called video terminal to the calling video terminal; Same as alternate video Call quality measurement method of a video call call comprising a. delete The method of claim 1, The step of setting a substitute video to be transmitted to the calling video terminal when the video call call is formed with the calling video terminal in the called video terminal, The reference video stored in the called video call quality measuring device connected to the called video terminal is transmitted to the called video terminal and the reference video is set as an alternative video of the called video terminal. How to measure call quality. The method of claim 1, The step of forming a video call between the calling video terminal and the called video terminal, The calling video call quality meter connected to the calling video terminal transmits a signal requesting to the calling video terminal to transmit a video call call connection request signal to the called video terminal, and the calling video terminal transmits a signal to the calling video terminal. And transmitting a video call call connection request signal to the called video terminal, and receiving a video call call connection response signal from the called video terminal in response thereto. The method of claim 1, The reproduction of the replacement video in the called video terminal and transmitting to the calling video terminal through the video call, And when the called video call quality measuring device connected to the called video terminal transmits a signal indicating to play the replacement video to the called video terminal, the called video terminal plays the replacement video. How to measure the call quality of a call arc. The method of claim 1, Comparing the alternative video transmitted from the calling video terminal with the comparison video stored in advance in the calling video call quality measuring unit, Detecting a sync frame included in the replacement video transmitted from the calling video terminal; Storing a substitute image of a predetermined length from the sync frame; Comparing the stored comparison image of a length corresponding to the replacement image of the predetermined length with the stored replacement image of the predetermined length as a reference image; Call quality measurement method of a video call call comprising a. In the video call call quality measurement apparatus for measuring the call quality of the video call call between the calling video terminal and the called video terminal connected to the calling video terminal, An input / output port connected to the calling video terminal for transmitting and receiving control signals and data; An alternative video storage for storing an alternative video transmitted by the calling video terminal, wherein the alternative video is received and transmitted from the called video terminal when the calling video terminal forms a video call with the called video terminal; A comparison image storage unit which stores a comparison image to be compared with a replacement image transmitted from the calling image terminal; An image comparison unit comparing the replacement image stored in the replacement image storage unit with a comparison image stored in the comparison image storage unit as a reference image for measuring call quality; And Control unit for controlling the operation of the input / output port, the replacement image storage unit, the comparison image storage unit and the image comparison unit Video call call quality measuring apparatus comprising a. delete The method of claim 7, wherein The substitute video transmitted from the called video terminal to the calling video terminal transmits the reference video stored in the called video call quality meter connected to the called video terminal to the called video terminal, and transmits the reference video. An apparatus for measuring video call call quality, characterized in that set as a substitute video of a called party's video terminal. The method of claim 7, wherein The substitute image storage unit detects a sync frame included in the substitute image transmitted from the calling video terminal, and stores a substitute image of a predetermined length from the sync frame, The image comparator compares the stored substitute image of a predetermined length with a comparison image of a length corresponding to the substitute image of the predetermined length as a reference image for measuring call quality. Video call call quality measurement apparatus, characterized in that.

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