Video call quality measurement system and method using virtual camera

Abstract

A video call quality measurement system according to the present invention comprises: a real camera; a video storage unit in which one or more moving image files are stored; a mobile communication terminal including a virtual camera application and one or more video call applications; and video call quality measurement equipment for measuring the quality of a video call by comparing an original video and a video received via the mobile communication terminal over a wired / wireless communication network. The virtual camera application includes: a virtual camera unit for recognizing the virtual camera as a hardware device such as a real camera; a camera switching unit for selectively connecting the real camera and the virtual camera unit to the video call application; a video processing unit for processing a moving image to be output to the virtual camera unit; a user interface via which a user sets, in the video storage unit, a moving image to be processed by the video processing unit; and a camera control unit for controlling the moving image set via the user interface to be output and processed in the video processing unit, and controlling the camera switching unit to selectively transmit outputs of the real camera and the virtual camera unit to the video call application.

Description

System and method for measuring video call quality using a virtual camera

[0001] The present invention relates to a system and method for measuring video call quality using a virtual camera, and more specifically, to a system and method for measuring video call quality through various video call apps that eliminates the influence of a real camera as a quality degradation factor by providing a video reproduced by a virtual camera as an input video instead of a video from a real camera, regardless of the type of video call app.

[0002] Recently, in addition to the video calling application programs pre-installed on mobile devices (hereinafter simply referred to as "apps"), a wide variety of video calling apps have been proposed and are being actively used, such as KakaoTalk's FaceTalk, LINE's video calling function, Google's Duo, and Apple's FaceTime. Furthermore, various video conferencing apps utilizing the physical camera of a mobile device or a webcam connected to a desktop PC or laptop PC have been proposed and are being actively used. Hereinafter, video calling apps and video conferencing apps will be collectively referred to as "video calling apps," and the explanation will proceed using mobile devices as examples of the devices used therein.

[0003] Meanwhile, the quality measurement of a video call (including multi-party video calls such as group calls) via such conventional video call apps can be performed by determining the degree of degradation of the receiving video relative to the sending video while the video and audio input through a physical camera and microphone equipped on a mobile communication terminal (since this invention targets only video, the explanation will proceed using only video as an example) are transmitted and recorded via the same video call app on the other party's mobile communication terminal. For example, during a video call, the original video is captured by a physical camera equipped on the sending mobile communication terminal and transmitted to the receiving mobile communication terminal, and the quality of the communication network or the corresponding video call app is measured based on the degree of degradation of the received video relative to the original video while the receiving mobile communication terminal records the received video.

[0004] However, according to these conventional video call quality measurement methods, distortion can occur in the original video transmitted to the receiving end due to factors such as the shooting angle, changes in ambient lighting, the performance of the actual camera, or minute shaking during the process of capturing the original video by the actual camera. Consequently, the cause of video call quality degradation cannot be attributed solely to issues with the communication network or the video call app, and there was a problem in that video call quality could not be accurately measured.

[0005] Considering these problems, a technology that replaces video input through a real camera with another video prepared in advance and transmits it through the other party's mobile communication terminal is proposed in the following prior art 1 and 2 for the purpose of measuring service quality for video calls.

[0006] However, the technology proposed as Prior Art 1 below is a technology primarily used in 3G (WCDMA) mobile communication networks, and performs video calls in a low-speed data environment according to the H.324M protocol defined by the ITU-T. It replaces video input from a real camera by inputting video through a video call emulator or a video call interface provided by a mobile communication terminal. Since the technology proposed as Prior Art 1 was developed to suit the 3G (WCDMA) environment where only video call services using H.324M existed, it has problems such as having to be redeveloped to suit other video call services even if they exist.

[0007] FIG. 1 is a block diagram schematically illustrating a device for measuring the quality of a video call service in real time as proposed in the following prior art 2. As shown in FIG. 1, assuming a situation in which a first terminal (310) and a second terminal (320) conduct a video call in the prior art 2, the first terminal (310) can generate a media stream by encoding and packetizing an input signal (312), which is a signal for a video captured through a camera (311), through an encoder and a packetizer (313), and then transmit the generated media stream to the second terminal (320) through a network (170). At this time, the second terminal (320) can decode and depacketize the media stream received from the first terminal (310) through a decoder and a depacketizer (321) to generate an output signal (322) and then output it through an output unit (323) so that video and audio for a video call can be output from the second terminal (320).

[0008] Meanwhile, to measure the quality of the video call service, the first terminal (310) may transmit the original video stored in the first storage (314) to the second terminal (320) instead of the input signal (312), and in this process, the original video may be processed through the original video processing unit (315). For example, since the frame rate and / or resolution of the video call service may not match the pre-generated original video, the first terminal (310) may process the original frames included in the original video through the original video processing unit (315) so that the frame rate and resolution of the original video correspond to the frame rate and resolution of the video call service for which the quality is to be measured. As a more specific example, if the frame rate of the video input through the camera is 15 fps (frames per second) and the frame rate of the original video is 30 fps, the original video can be replaced by skipping one frame at a time, that is, if the indices of the original frames included in the original video are assigned as '1, 2, 3, 4, 5, 6, 7, 9', the original frames of '1, 3, 5, 7, 9' can be replaced with the frames of the video input through the camera.

[0009] However, according to the aforementioned prior art 2, each of the various video call apps must provide its own API (Application Programming Interface) to connect an original image processing unit (315) for replacing the image of a real camera with the original image, and an encoder and packetizer (313), although not illustrated. Accordingly, there was a problem of duplicate development costs incurred in creating and linking a dedicated API for each video call app according to its type and characteristics in order to provide a function to transmit a replacement image instead of the image input through the real camera.

[0010] The main objective of the present invention is to provide a video call quality measurement system and method that, when measuring the quality of a video call through various video call apps, eliminates the influence of the actual camera as a quality degradation factor by providing an image reproduced by a virtual camera instead of an actual camera image as an input image, regardless of the type of video call app.

[0011] According to one feature of the present invention for achieving the aforementioned purpose, a video call quality measurement system using a virtual camera is provided, comprising a mobile communication terminal equipped with a real camera, an image storage unit storing one or more video files, a virtual camera app, and one or more video call apps, and a video call quality measurement device that measures the quality of a video call by comparing an image received through the mobile communication terminal via a wired / wireless communication network with an original image. The virtual camera app comprises: a virtual camera unit that recognizes the virtual camera as a hardware device such as a real camera; a camera switching unit that selectively connects the real camera and the virtual camera unit to the video call app; an image processing unit that processes a video to be output to the virtual camera unit; a user interface that receives a video to be processed by the image processing unit from a user in the image storage unit, and a camera control unit that controls the video set through the user interface to be output to the image processing unit for processing, and selectively transmits the output of the real camera and the virtual camera unit to the video call app.

[0012] In the aforementioned configuration, the video call quality measurement device is a desktop or laptop computer, tablet PC, or smartphone equipped with a video analysis tool.

[0013] The video processing unit processes the video set by the user at the same frame rate and resolution as the actual camera.

[0014] According to another feature of the present invention, a method for measuring video call quality using a virtual camera is provided, comprising: (a) a step in which the virtual camera app receives a video to be used for measuring video call quality from a user; (b) a step in which the virtual camera app turns on a virtual camera unit, which is a component installed in the virtual camera app, so that the video call app recognizes the virtual camera as a hardware device such as a real camera; (c) a step in which the virtual camera app processes the video received in step (a) and transmits it to the other party terminal when a video call is connected with the other party terminal through the video call app; and (d) a step in which the video call quality measuring equipment measures the quality of the video call by comparing the video received from the other party terminal with the original video.

[0015] In the aforementioned configuration, the video call quality measurement device is a desktop or laptop computer, tablet PC, or smartphone equipped with a video analysis tool.

[0016] The image processing in step (c) above includes processing the video set by the user to the same frame rate and resolution as the actual camera.

[0017] According to the system and method for measuring video call quality using a virtual camera of the present invention, the video selected by the user through the virtual camera during the video call process is consistently transmitted to the receiving terminal exactly as the original video, thereby allowing the quality of the communication network or video call app to be accurately measured while excluding the influence of the actual camera.

[0018] FIG. 1 is a block diagram schematically illustrating a device for measuring the quality of a video call service in real time as proposed in Prior Art 2.

[0019] FIG. 2 is a diagram illustrating the schematic configuration of a video call quality measurement system using a virtual camera according to an embodiment of the present invention.

[0020] FIG. 3 is a functional block diagram of a video call quality measurement system using a virtual camera according to an embodiment of the present invention.

[0021] FIG. 4 is a flowchart for explaining a method for measuring video call quality based on an embodiment of FIG. 3.

[0022] FIG. 5 is a figure illustrating the effect of the video call quality measurement system through a virtual camera of the present invention.

[0023] Hereinafter, preferred embodiments of the system and method for measuring video call quality using a virtual camera according to the present invention will be described in detail with reference to the attached drawings.

[0024] FIG. 2 is a diagram illustrating the schematic configuration of a video call quality measurement system using a virtual camera according to an embodiment of the present invention. As illustrated in FIG. 2, according to the video call quality measurement system using a virtual camera according to an embodiment of the present invention, both mobile communication terminals performing the video call can serve as both the sending and receiving terminals. During this video call process, the sending mobile communication terminal blocks the image from its actual camera and transmits the image played back through a virtual camera—which operates to be recognized by various video call apps as a hardware device identical to the actual camera—to the receiving mobile communication terminal via a wired or wireless communication network. Subsequently, the receiving side stores the received image from the receiving mobile communication terminal in a video call quality measurement device and measures the quality of the video call by comparing it with the original image, for example, using VQML, a video analysis tool developed by the applicant. TM You can measure the quality of a video call using this.

[0025] Video call quality measurement equipment is, for example, VQML, a video analysis tool. TMThis can be implemented on a desktop or laptop computer equipped with this, a tablet PC, or a smartphone equipped with a video call app and the virtual camera app described below.

[0026] FIG. 3 is a functional block diagram of a video call quality measurement system using a virtual camera according to an embodiment of the present invention, and for convenience, only the configuration related to video calls of a calling mobile communication terminal is illustrated. As shown in FIG. 3, a video call quality measurement system using a virtual camera according to an embodiment of the present invention may largely comprise a real camera (100), a video storage unit (150) in which one or more video files that can be provided to a counterparty mobile communication terminal through a virtual camera are stored, various video call apps (400), and a virtual camera app (200) of the present invention.

[0027] In the above configuration, a physical camera (100) and a video storage unit (150), which is a memory, may be basically provided in a mobile communication terminal. One or more video call apps (400) that may be installed in the mobile communication terminal may include various video call apps installed by the user in addition to the video call apps basically provided by the mobile communication terminal, such as KakaoTalk's FaceTalk, LINE's video call function, Google's Duo, and Apple's FaceTime as described above, and may also include various video conferencing apps. Each of these video call apps (400) may be composed of a camera interface (410), an encoder (420), and a packetizer (430) as in the past.

[0028] Meanwhile, the virtual camera app (200) of the present invention may specifically comprise a virtual camera unit (240), a camera switching unit (250) that selectively connects a real camera (100) and the virtual camera unit (240) to various video call apps (400), an image processing unit (230), a user interface (UI) (220) that receives a video to be processed by the image processing unit (230) from a user in an image storage unit (150), and a camera control unit (210).

[0029] First, the virtual camera unit (240) is a component that enables various video call apps (400) to recognize the virtual camera as a hardware device such as a real camera (100), and can be implemented, for example, in the Hardware Abstraction Layer (HAL) of the Android Architecture.

[0030] Here, the Hardware Abstraction Layer (HAL) is intended to provide a clean and consistent interface by concealing the specific characteristics and complex internal structure of the hardware, thereby enabling various video call applications to discover and use the hardware of the mobile communication terminal through a simple and abstracted API, regardless of the type of underlying hardware (in this invention, a camera).

[0031] In addition to this, the virtual camera unit (240) can be implemented in the framework layer of iOS and macOS or developed as a driver for Windows.

[0032] Next, the camera switching unit (250) selectively transmits a video signal captured through the actual camera (100) or a video signal input through the virtual camera unit (240) to the camera I / F (interface) of various video call apps (400). The video processing unit (230) processes the video of the video storage unit (150), which is set by the user of the virtual camera app (200) through the user interface (220), into a form identical to the input video of the actual camera (100), for example, into a video stream having the same frame rate and resolution, and transmits it to the virtual camera unit (240).

[0033] Finally, the camera control unit (210) controls the video stored in the video storage unit (150) to be output to the video processing unit (230) for processing as set through the user interface (220), and controls the switching operation between the real camera (100) and the virtual camera unit (240) to selectively transmit the output of the real camera (100) and the virtual camera unit (240) to the camera interface (410) of the video call app (400).

[0034] The user interface (220), image processing unit (230), camera switching unit (250), and camera control unit (210) can be implemented, for example, in the application layer of the Android architecture.

[0035] In this way, the video set by the user during the video call process passes through the virtual camera unit (240) and is transmitted in real time to the other party's terminal via a wired / wireless communication network as if it were a video captured by a real camera (150), thereby completely excluding the influence of the real camera (100) and allowing only the quality of the communication network or video call app to be fully measured.

[0036] FIG. 4 is a flowchart for explaining a method for measuring video call quality based on an embodiment of FIG. 3, and unless otherwise stated, it is performed primarily by a camera control unit (210). As illustrated in FIG. 4, according to a method for measuring video call quality using a virtual camera according to an embodiment of the present invention, in step S100, while the virtual camera app (200) is running, in step S110, a video to be used for measuring video call quality is selected by the user.

[0037] Next, in step S120, it is determined whether the virtual camera unit (240) is turned on. The turning operation of the virtual camera unit (240) can be performed by the camera control unit (210) controlling the camera switching unit (250) to connect the virtual camera unit (240) to the video call app (400) when an on command is input through the user interface (220).

[0038] If the virtual camera unit (240) is not turned on in step S120, step S120 is repeated; however, if it is turned on, the process proceeds to step S130 to wait for a video call connection, and in step S140, it is determined whether the video call is connected. If the video call is not connected in step S140, step S130 is repeated; however, if it is connected, the process proceeds to step S150 to transmit a video processed in a video call quality measurement format through the video processing unit (230), for example, a video processed to have the same frame rate and resolution as the actual camera (100), to the receiving terminal through the virtual camera unit (240).

[0039] In step S160, the video received from the other party, the sending terminal, is stored, and in step S170, it is determined whether the video call has ended. If the video call has not ended in step S170, step S160 is repeated; whereas if it has ended, the quality of the video call, e.g., the quality of the communication network or the corresponding video call app, is measured using the aforementioned video call quality measurement equipment.

[0040] FIG. 5 is a diagram illustrating the effect of the video call quality measurement system through a virtual camera according to the present invention. As shown in FIG. 5, in the past, as shown in (a), during the process of capturing the original video by a real camera during a video call, distortion may occur in the original video transmitted to the receiving end due to changes in the shooting angle or ambient lighting, the performance of the real camera, or slight shaking. Therefore, the cause of the degradation of video call quality cannot be attributed solely to problems caused by the communication network or the video call app, and consequently, there was a problem in that the video call quality could not be accurately measured.

[0041] On the other hand, according to the video call quality measurement system of the present invention, as illustrated in (b), the video selected by the user through a virtual camera during the video call process is consistently transmitted to the receiving terminal as the original video, thereby allowing the quality of the communication network or video call app to be accurately measured while excluding the influence of the actual camera.

[0042] The system and method for measuring video call quality using a virtual camera according to the present invention are not limited to the aforementioned embodiments and may be implemented with various modifications within the scope permitted by the technical concept of the present invention. Accordingly, the scope of rights of the present invention should be determined by the description in the following claims.

Claims

1. A mobile communication terminal equipped with a physical camera, a video storage unit storing one or more video files, a virtual camera app, and one or more video call apps, and It comprises a video call quality measurement device that measures the quality of a video call by comparing a video received through a mobile communication terminal via a wired / wireless communication network with an original video, The above virtual camera app includes a virtual camera unit that recognizes the virtual camera as a hardware device similar to a real camera; A camera switching unit that selectively connects a real camera and a virtual camera unit to a video call app; An image processing unit that processes video to be output to a virtual camera unit; A user interface that receives a video to be processed in the video processing unit from the user, and a video storage unit, and A video call quality measurement system using a virtual camera comprising a camera control unit that controls a video set through a user interface to be output to a video processing unit for processing, and controls a camera switching unit to selectively transmit the output of a real camera and a virtual camera unit to a video call app.

2. In Claim 1, A video call quality measurement system using a virtual camera, characterized in that the video call quality measurement equipment is a desktop or laptop computer, tablet PC, or smartphone equipped with a video analysis tool.

3. In claim 1 or 2, A video call quality measurement system using a virtual camera, characterized in that the video processing unit processes a video set by the user to the same frame rate and resolution as a real camera.

4. Performed in a video call quality system including a mobile communication terminal equipped with a physical camera, a virtual camera app, and one or more video call apps, and a video call quality measurement device, and (a) A virtual camera app receives a video from the user to be used for measuring video call quality; (b) a step of turning on the virtual camera unit, which is a component installed in the virtual camera app, so that the virtual camera app recognizes the video call app as a hardware device like a real camera; Step (c) in which, when a virtual camera app establishes a video call with a counterparty terminal through a video call app, the virtual camera app processes the video set in step (a) above and transmits it to the counterparty terminal, and A method for measuring video call quality using a virtual camera, comprising step (d) in which a video call quality measuring device measures the quality of a video call by comparing a video received from a counterparty terminal with an original video.

5. In Claim 4, A method for measuring video call quality using a virtual camera, characterized in that the video call quality measuring device is a desktop or laptop computer, tablet PC, or smartphone equipped with a video analysis tool.

6. In claim 4 or 5, A method for measuring video call quality using a virtual camera, characterized in that the video processing in step (c) above processes the video set by the user to the same frame rate and resolution as the actual camera.

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