WO2008131644A1

WO2008131644A1 - A method, device and system for realizing picture switching in the video service

Info

Publication number: WO2008131644A1
Application number: PCT/CN2008/000848
Authority: WO
Inventors: Xiangwen Zhu; Zongwu Wu; Xufeng Zhou; Yan Mo; Xin Qu; Jiafeng Liu; Yuan Li
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-04-27
Filing date: 2008-04-25
Publication date: 2008-11-06
Also published as: CN100583985C; CN101031065A

Abstract

A method, device and system for realizing a picture switching in the video service, for solving the problem of the prior art that a user participating in the video service can not select a picture display mode to watch the picture image according to his needs. The method of the invention includes: receiving a switching request message by a multipoint control unit, wherein the request message includes the picture display mode for indicating the amount of the sub-picture displayed on the picture; determining the required picture mixers according to the picture display mode by the multipoint control unit, and outputting the picture image corresponding to the requested picture display mode to the user terminals which have sent the switching request messages. With the method according to the invention, a user can choose the picture display mode according to his needs, at the same time, can also perform the switching between the multi-picture display mode and the single- picture display mode, therefore the demand of different users are satisfied.

Description

Method, device and system for realizing picture display in video service

The present invention relates to video technologies, and in particular, to a method, device and system for implementing picture switching in a video service. Background technique

The video conferencing system allows conference participants to interact with voice, video, and data in real time, greatly facilitating communication and communication between conference participants. In the network structure of the video conference system shown in FIG. 1 , a multipoint control unit (MCU) is connected to each site participating in the conference, and is configured to receive the site signal, process the site signal, and deliver the processed site signal to the site. The conference sites of the conference; the user terminal equipment mainly realizes the input and output of voice, image and data, as well as the functions of communication connection and data transmission and reception; more than two user terminal equipments and MCUs construct a multi-point, real-time conference communication environment. The user views images of other users through the terminal device and listens to the sounds of other users.

In order to meet the need for participants in a video conference to simultaneously understand the image information of all or part of other participants at the same time, the prior art provides a way to realize multi-screen display in a video conference:

The main processing flow of a multi-screen display implementation method is as follows:

1. The site image terminal data from each conference terminal is processed by the H.221 frame processing module to form a plurality of source high-speed serial image data code streams that meet the H.221 standard;

2. The plurality of source high-speed serial image data streams are exchanged through the source high-speed serial data channel and exchanged to one or more target high-speed serial data channels to form one or more of the video wall target monitoring terminals. Target high speed serial image data stream;

3. Sending the target image data stream to the image decoding module, de-framing to form an image stream of H.261 format or H.263 format, and then performing digital image decoding to obtain a CCIR601 format standard digital image and a common intermediate format CIF standard number. image; 4. The CCIR601 format standard digital image is encoded by the analog image, converted into an analog video signal and sent to the video wall target monitoring terminal for display;

5. The CIF standard digital image is sent to the picture combining module to be combined into a "combined mode of the fixed mode, and the combined picture is encoded and then framed to form a multi-picture image data code stream, through exchange mesh switching and H.221 frames. The processing module processes and sends it to each terminal, thereby implementing multi-screen display of each terminal.

The technical solution is mainly for a specific conference television system, and the conference video wall needs to be set up on the MCU side, and the application has a large limitation; in addition, the user can only view the same multi-picture image and the multi-screen display function is single. Summary of the invention

The embodiment of the invention provides a method, a device and a system for implementing a screen switching in a video service, and a user for participating in a video service can independently select a screen display mode to view an image according to requirements.

A method for implementing a screen display in a video service, comprising the steps of:

The multipoint control unit MCU receives a handover request message including a screen display mode for indicating the number of sub-pictures displayed on the screen.

The MCU determines a required picture mixer based on the picture display mode, and outputs a picture image corresponding to the requested picture display mode to the user terminal that transmits the switching request message.

A screen display device implemented in a video service, comprising:

a control module, configured to manage multi-picture control information, and dynamically determine a picture mixer according to a picture display mode;

a decoding module, configured to decode a video source image data stream of each user terminal to obtain a plurality of screen image information;

a picture combining module, configured to perform multi-screen combination by one or more picture mixers according to the multi-picture control information, to obtain combined multi-picture image information;

The encoding module is configured to encode the combined multi-picture image information accordingly. A video service system, comprising: a multipoint control unit MCU, wherein the MCU is configured to connect to a plurality of user terminals through a network, and receive a handover request message including a screen display mode sent by the user terminal, and according to the screen The display mode determines a required screen mixer, and outputs a screen image corresponding to the requested screen display mode to the user terminal transmitting the switching request message; the screen display mode is for indicating the number of sub-screens displayed on the screen.

The multi-point control unit MCU outputs a screen image corresponding to the screen display mode to the terminal where the user is located according to the screen display mode selected by the user, and the user participating in the video service can view the image in the same screen display mode, or can be independent according to needs. Selecting the screen display mode to view the image realizes flexible switching between the multi-screen display mode, the multi-screen display mode and the single-screen display mode, and satisfies the user's demand for differently viewing the conference image. DRAWINGS

1 is a schematic structural diagram of a conference video system in the prior art;

2 is a schematic structural diagram of a multipoint control unit according to an embodiment of the present invention;

3 is a schematic structural diagram of a screen combination module according to an embodiment of the present invention;

4 is a schematic diagram of a multi-screen display mode according to an embodiment of the present invention;

FIG. 5 is a schematic diagram showing an implementation principle of displaying a conference image by a plurality of user terminals in a four-screen display mode according to an embodiment of the present invention; FIG.

6 is a schematic diagram of displaying, by a plurality of user terminals, a conference image in a four-screen display mode according to an embodiment of the present invention;

FIG. 7 is a flowchart of an implementation of displaying a conference image by user A selecting a six-screen display mode according to an embodiment of the present invention; FIG.

8 is a schematic diagram of a user A, B, and C. D terminal displaying a conference image when user A selects a six-screen display mode according to an embodiment of the present invention;

FIG. 9 is a flowchart of an implementation of displaying a conference image by a user C selecting a single screen display mode according to an embodiment of the present invention;

10 is a user A, B, and C when user C selects a single-screen display mode according to an embodiment of the present invention. D terminal displays a schematic diagram of the conference image;

FIG. 11 is a flowchart of implementing a frame identifier sub-picture according to an embodiment of the present invention;

FIG. 12 is a schematic diagram showing the display of a frame identifier sub-screen according to an embodiment of the present invention.

detailed description

In order to solve the problem that the multi-screen display function is single and the user cannot convert between the multi-screen and single-screen display modes in the prior art, the technical solution of the embodiment of the present invention is described in detail by taking a video conference system as an example.

As shown in FIG. 1 , the video conference system in this embodiment includes a multi-point control unit MCU and a plurality of user terminals connected to the MCU through a network. The MCU structure of the multi-point control unit is as shown in FIG. 2, and the MCU includes control. Module 20, decoding module 21, picture combining module 22, and encoding module 23;

The control module 20 is configured to manage multi-screen control information, which is obtained by negotiating with a user terminal participating in the video conference, and playing video menu prompt information to the user terminal participating in the video conference, and dynamically allocating the screen according to the screen display mode selected by the user. The multi-picture control information includes input video source information, picture mixture information, and multi-picture output information; the input video source information includes identification information of each decoder and pixel precision of each input video source image; The number of picture mixers to be supported, the multi-picture image pixel precision, and the attribute information of each picture mixer. The multi-picture image pixel accuracy is usually determined as the maximum image pixel accuracy in each participant terminal, and may also be based on system requirements. Setting, the attribute information of the screen mixer includes a mode of multi-screen display, a position of each sub-screen in the multi-screen display mode, and identification information of an encoder corresponding to each sub-screen; the multi-screen output information includes identifier information of each encoder, Correct The mixer identifier and output image pixel accuracy should be the same.

The control module 20 specifies a default picture mixer when the video conference is initialized, and the attribute of the picture mixer can be dynamically changed according to the number of user terminals participating in the video conference during the conference, but cannot be deleted; In the process, according to the screen selected by the user The mode determines the corresponding picture mixer, and the corresponding picture mixing mixer can be added, or these picture mixers can be deleted dynamically.

The decoding module 21 is composed of a plurality of decoders, and is configured to decode the video source image code stream of the user terminal participating in the video conference, and transmit the decoded video source image information to the screen combining module 22 through the data bus; Each of the output image streams is assigned a decoder, and each decoder decodes the input image stream using a decoding algorithm (such as H.263, MPEG-4, etc.) that matches the input image stream encoding algorithm. The image information is restored; each decoder supports multiple decoding algorithms, and an initialization matching algorithm is performed when assigned to the input image code stream.

The picture combining module 22 is configured to perform multi-screen combination on the plurality of video source image information output by the decoder by using one or more picture blenders according to the multi-picture control information, and transmit the combined multi-picture image information to the data bus through the data bus. Encoding module 23; as shown in FIG. 3, the picture combining module 22 further includes: an image data input unit 220, configured to receive video source image information output by the decoding module 21; and a plurality of first samplers 221 for Comparing the pixel precision of the corresponding video source image in the image data input unit 220 with the image pixel precision of the corresponding position of the video source image in the multi-picture, and when the two are inconsistent, sampling the video source image information, and sampling The subsequent video source image information is output to the picture mixer 222; otherwise, the video source image information is directly output to the picture mixer 222; the sampling includes upsampling and downsampling, such as dropping the image with a pixel precision of 704 X 576 (4CIF) Sampling an image of 352 x 288 (CIF) or upsampling an image with a pixel accuracy of 176^144 (QCIF) An image with a pixel precision of 352 x 288 (CIF); a picture blender 222, configured to perform multi-screen combination on each video source image information outputted in the first sampler 221, and output the combined multi-picture image information to a second sampler 223; the plurality of second samplers 223 are configured to compare the pixel precision of the multi-picture image output by the picture mixer 222 with the output image pixel precision in the multi-picture output information, and when the two are inconsistent, The screen image information is correspondingly sampled and the multi-picture image information obtained after sampling is transmitted to the image data output unit 224 through the data bus; otherwise, the multi-picture image information is directly output to the image data output unit 224; the image data output unit 224 The image information is output to the encoding module 23.

The picture mixer 222 in the picture combining module 22 may be one or more, the first picture The mixer is specified or set as the default screen mixer when the conference is initialized. The first screen mixer properties can be changed during the conference, but cannot be deleted. During the conference, other screen mixers can be added, or they can be dynamic. The screen mixer is deleted to meet the user's differentiated viewing requirements; the control module 20 refreshes the input video source information, the screen mixing information, and the multi-picture output information in the multi-picture control information according to the operation information of the user, first The sampler 221, the picture mixer 222, and the second sampler 223 perform corresponding processing in accordance with the new multi-picture control information.

The encoding module 23 is composed of a plurality of encoders, and is configured to encode the multi-picture image information output by the picture combining module 22, and form a multi-picture image compressed code stream matched with the decoding algorithm of the participating terminal, and output the same to each At the participating terminal, the participating terminal decodes the received multi-picture image compressed code stream and displays the multi-picture image locally; each encoder supports multiple encoding algorithms, and performs initial matching when assigned to the output image code stream, The encoder may correspond to one or more participating terminals; the schematic diagram of the multi-screen display of the participating terminal is as shown in FIG. 4, and the multi-screen display mode supported by each screen mixer may be any one of them, but is not limited to a few Kind of situation.

In this embodiment, when the video service is initialized, the MCU specifies a default picture blender and selects a picture display mode according to the business needs, and further performs multi-picture display by using the default picture mixer to realize multi-picture display, thereby reducing the picture blender. The number of uses, thus saving resources.

In order to more clearly explain the implementation process of the multi-screen display in this embodiment, a specific example will be described below.

Example 1: Users A, B, C, and D terminals are connected to a video conference. The video attributes of users A, B, C, and D are as follows:

User terminal image compression algorithm image pixel precision

A H.263 CIF ( 352x288 )

B MPEG-4 CIF ( 352x288 )

C H.263 QCIF ( 176x144 ) The D MPEG-4 QCIF ( 176x 144 ) control module initializes the user A, B, C, and D terminals to view the multi-screen display mode of the conference. The multi-screen display mode of the first screen mixer is set to the four-screen display mode, that is, the user A, The images of the B, C, and D terminals each occupy 1/4 of the picture, and the pixel precision of the multi-picture image is selected as CIF (352 x 288); as shown in Figure 5, the implementation principle of the four-picture display is as follows:

After the user accesses the site, the control module allocates a decoder corresponding to each user and initializes a decoding algorithm. Each decoder restores the video source image stream input by each user to a corresponding video source image information, and outputs the same; The decoding algorithm used by the decoder 1 corresponding to the decoder 1 and the user C terminal is initialized to H.263, and the decoding algorithm used by the decoder 2 corresponding to the user B terminal and the decoder 4 corresponding to the user D terminal is initialized to MPEG-4; The decoders 1, 2, 3, and 4 respectively decode the image code streams of the users A, B, C, and D terminals, and output the restored video source image information to the image data input units in the screen combination module.

The first sampler 1 and 2 determine that the decoded image information corresponding to the user A and the B terminal needs to be downsampled according to the pixel precision of the video source image input by the user and the B terminal and the multi-picture image pixel precision, so the first sampler 1 and 2 The decoded image information corresponding to the user A and the B terminal is downsampled, and the image obtained with the image pixel precision of QCIF (176 χ 144 ) is output to the picture mixer; the decoded image corresponding to the user (and the D terminal) Since the pixel precision is QCIF (176 X 144 ), the first sampler 3, 4 determines that the image information does not need to be sampled, and directly outputs the decoded image information to the picture mixer.

The screen mixer combines the video source image information corresponding to the user A, B, and C. D terminals output by the first sampler 1, 2, 3, 4 into a four-screen image information according to the multi-screen display mode in the screen mixing information. And output it to the second sampler.

The second sampler 1 and 2 determine that the four-picture image information does not need to be sampled for the user A and the B terminal according to the output image pixel precision of each user terminal, and output the same to the corresponding encoder 1 and 2 through the image data output unit. The second sampler 3, 4 determines that the four-picture image information is down-sampled for the user (:, D terminal, therefore, the second sampler 3, 4 downsamples the four-picture image information, The images obtained by sampling and having the pixel precision of QCIF (176 X 144 ) are respectively output to the corresponding encoders 3 and 4 through the image data output unit.

The encoders 1, 2, 3, and 4 respectively encode the four-picture image information output by the picture combining module, and output an image compressed code stream matching the user A, B, C, and D terminal decoding algorithms to the corresponding user terminal.

The user A, B, C, and D terminals decode the received image compressed code stream and display the four-picture images locally. The schematic diagram of the display is shown in FIG. 6.

In the above example, the user A, B, C, and D terminals view the conference image in the same four-screen display mode. In this embodiment, the user can select other multi-screen display modes to view the conference image through the terminal operation, and freely switch the screen display. The mode does not affect the viewing of other participants, as shown in Figure 7, the specific implementation process of the user switching the multi-screen display mode is as follows:

Step 600: The MCU periodically plays a video menu prompt message during the conference, prompting the user to perform related operations.

Step 601: The user selects a corresponding multi-screen display mode by using a terminal operation when the conference image is required to be viewed in other multi-screen display mode according to the prompt information, and the terminal where the user is located sends a handover request to the MCU.

Step 602: The MCU updates the multi-picture control information according to the handover request, and determines a required picture mixer.

Step 603: The MCU performs multi-screen combination by the determined picture blender according to the updated multi-screen control information, and outputs a multi-screen image that satisfies the multi-screen display mode selected by the user and outputs to the other user terminal to the user terminal that sends the switching request. Corresponding multi-screen image.

Example 2: During the conference of the first instance, the user A selects the six-screen display mode to view the conference image through the terminal operation, and the user A terminal sends a request for switching the screen display mode to the MCU, and the MCU updates the screen mixing information according to the request. And determining that the second picture mixer needs to be added, and the attributes thereof include a six-picture display mode, a position of each sub-picture in the six-picture display mode, and encoder identification information corresponding to each sub-picture. The first sampler selects the users A, B, C according to the input video source information and the screen mixing information and the attribute information of the first screen mixer and the second screen mixer. Decoding the video source image information corresponding to the D terminal and performing corresponding sampling processing thereon; the first picture mixer and the second picture mixer respectively perform four picture combination and six picture combination on each video source image information; the second sampler will The four-picture image information combined by the first picture mixer is output to the encoder 2 corresponding to the user B terminal through the image data output unit, and the combined four-picture image information is downsampled, and the sampled four-picture image information is passed. The image data output unit outputs to the encoders 3 and 4 corresponding to the C and D terminals of the user, and outputs the six-picture image information combined by the second picture mixer to the encoder 1 corresponding to the user A terminal through the image data output unit; 1, 2, 3, 4 encode the multi-picture image information corresponding to the output of the picture combination module and output it to the corresponding user terminal; the user A, B, C, D terminal decodes the received image compressed code stream and then localizes Display corresponding multi-screen images, that is, user A views the six-screen image of the conference on the terminal, and users B, C, and D are at their respective terminals. The four-screen image of the conference is viewed, and the schematic diagram of the multi-screen display of each user terminal is as shown in FIG. 8.

The user selects the multi-screen display mode to view the conference image through the terminal operation, and can also select the single-screen display mode to view the conference image according to the need, and the specific implementation process of the user selecting the single-screen display mode to view the conference image is as follows:

Step 700: The MCU periodically plays a video menu prompt message during the conference, prompting the user to perform related operations.

Step 701: The user selects a corresponding single-screen display mode by using a terminal operation when the conference image is required to view the conference image according to the prompt information, and the user terminal sends a handover request to the MCU.

Step 702: The MCU updates the multi-screen control information according to the handover request.

Step 703: The MCU directly outputs the corresponding single-screen image to the user terminal that sends the handover request, and performs multi-screen combination by the original screen mixing according to the multi-screen control information, and outputs the corresponding multi-screen image to other user terminals.

Example 3: During the conference of the second instance, after the user C selects to view the single-screen image of the user A through the terminal operation, the user C terminal sends a request for switching the screen mode to the MCU, and the MCU updates the screen mixing information according to the request, and Make sure only the first picture mixer and the second picture are needed a mixer, the corresponding attribute information remains unchanged; the first sampler selects the user A, B, C, D according to the input video source information and the screen mixing information and the attribute information of the first picture mixer and the second picture mixer Decoding picture information corresponding to the terminal and performing corresponding sampling processing; the first picture mixer and the second picture mixer respectively perform four picture combination and six picture combination; and the second sampler combines the four picture picture information after combining the first picture mixer Outputting to the encoder 2 corresponding to the user B terminal by the image data output unit, down-sampling the combined four-picture image information, and outputting the four-picture image information obtained after sampling to the user D terminal through the image data output unit The encoder 4 outputs the six-picture image information combined by the second picture mixer to the encoder 1 corresponding to the user A terminal through the image data output unit; the first sampler downsamples the decoded image pixel information corresponding to the user A terminal into After QCIF ( 176 X 144 ), the image information after sampling is output to the user C terminal through the image data output unit. Encoder 3; Encoder 1, 2, 3, 4 encodes the picture image information corresponding to the picture combination module and outputs it to the corresponding user terminal; the user A, B, C, D terminal compresses the received image After the code stream is decoded, the corresponding picture image is displayed locally, that is, user C views the image information of user A on the terminal, and user A views the image information of the six-picture mode on the terminal, and user B and user D respectively watch on the terminal. Four-screen image information; A schematic diagram of multi-screen display of each user terminal is shown in FIG.

In addition, in this embodiment, a frame identifier of a certain sub-screen in the multi-screen is highlighted to highlight the image of the screen, for example, a frame of the sub-picture of the currently speaking D is frame-marked to highlight the image, as shown in FIG. The specific process of highlighting the border logo is as follows:

Step 800: The MCU determines the sub-picture information corresponding to the user terminal that needs the frame identifier.

Step 801: The MCU updates the multi-screen control information.

Step 802: The MCU records the sub-picture information into a picture mixer.

Step 803: After the screen mixer completes the multi-screen combination, the frame image is identified by the frame. Step 804: The MCU outputs a screen image with a frame identifier to the user terminal.

The process of decoding, multi-picture combining and encoding of the image information in the process is the same as the implementation process in the above embodiment, and will not be described again; the schematic diagram of the multi-screen display of the user A, B, C, D terminal is as shown in FIG. . In the implementation method of the multi-screen display provided in the embodiment, the participant terminal views the conference image in the same multi-screen display mode at the initial stage of the conference, and during the conference, the user can select the multi-screen display mode for viewing the conference image according to the need. Or the single-screen display mode satisfies the requirement of the user to separately view the conference image; in this embodiment, the user can switch between the multi-screen display mode and the single-screen display mode through the terminal operation, and the implementation method is simple and flexible; In this embodiment, the sub-pictures in the multi-picture are highlighted by the frame, which satisfies the needs of business diversification.

The video conference is taken as an example to describe the implementation process of the technical solution of the embodiment of the present invention. However, the technical solution of the embodiment of the present invention is not limited to video conference, and is also applicable to other video services, such as an interactive voice response (IVR). The service, the multi-participating video communication service, etc., when the above method is implemented in other video service systems, the functional requirements on the processor (such as the MCU) are similar to or the same as the MCU function in the embodiment, and the screen display and the screen are realized. The process of the handover is the same as the implementation process in this embodiment, and details are not described herein again. The spirit and scope of the invention. Therefore, it is intended that the present invention cover the modifications and variations of the invention as claimed.

Claims

Rights request

A method for displaying a screen in a video service, comprising the steps of: a multipoint control unit MCU receiving a handover request message, the request message comprising a screen display mode for indicating the number of sub-screens displayed by the screen;

The method according to claim 1, wherein when the screen display mode is the single-screen display mode, the corresponding single-screen image is directly output to the user terminal that sends the switching request message; In the multi-screen display mode, the multi-screen combination is performed by the determined screen mixer, and the corresponding multi-screen image is output to the user terminal that transmits the switching request message.

The method according to claim 1 or 2, wherein, when the video service is initialized, the MCU specifies a default picture mixer, and the default picture mixer cooperates with the video service according to the multi-picture control information. The video source image information corresponding to the user terminal is multi-screen combined, and the MCU outputs the combined multi-screen image to each user terminal.

The method according to claim 3, wherein the MCU dynamically modifies the attribute information of the default picture mixer according to the number of user terminals participating in the video service during the video service.

The method according to claim 4, wherein the attribute information includes a multi-screen display mode and a display position of each sub-screen.

The method according to claim 3, wherein the MCU records related information of the sub-picture image that needs the frame identifier to the picture mixer, and the picture mixer completes the multi-picture combination and the sub-picture The image is bordered.

7. The method according to claim 3, wherein when the picture combiner combines the video source image information, the method comprises the steps of:

Comparing the pixel precision of the video source image information with the pixel precision of the corresponding position of the video source image information in the multi-picture; When the two are inconsistent, the video source image information is sampled, and the sampled video source image information is multi-screen combined. Otherwise, the video source image information is directly combined into multiple screens.

8. The method according to claim 7, wherein after the multi-screen combination of the video image information, the pixel precision of the output multi-picture image information and the pixel precision of the output image information in the multi-picture output information are compared. When the two are inconsistent, the multi-picture image information is correspondingly sampled and encoded, otherwise, the multi-picture image information is directly encoded.

9. A picture display device implemented in a video service, comprising: a control module, configured to manage multi-picture control information, and dynamically determine a picture mixer according to a picture display mode;

a picture combining module, configured to perform multi-screen combination by using one or more picture mixers to obtain combined multi-picture image information;

The encoding module is configured to encode the combined multi-picture image information accordingly.

The device according to claim 9, wherein the control module specifies a default picture mixer for multi-screen combination when the video service is initialized; the control module selects according to the user during the video service process. The screen display mode determines the desired screen mixer.

The device according to claim 10, wherein the control module dynamically modifies the attribute information of the default picture mixer according to the number of user terminals participating in the video service during the video service.

The device according to any one of claims 9 to 11, wherein the control module records related information of the sub-picture image that needs the frame identification to the picture mixer, and the picture mixer completes the multi-picture. After the combination, the sub-picture image is marked with a border.

13. Apparatus according to claim 12, wherein said apparatus is a multipoint control unit MCU.

14. The apparatus according to claim 12, wherein said picture combining module further An image data input unit, a first sampler, a picture mixer, an image data output unit, and a second sampler, wherein

An image data input unit, configured to receive video source image information output by the decoding module; a first sampler, configured to input pixel precision of corresponding video source image information in the image data input unit and the video source image in multiple images The image pixel precision of the corresponding position is compared. When the two are inconsistent, the video source image information is sampled, and the sampled video source image information is output to the picture mixer; otherwise, the video source image information is directly output. To the picture mixer;

a picture mixer, configured to perform multi-screen combination on each video source image information outputted in the first sampler, and output the combined multi-picture image information to the second sampler;

a second sampler, configured to compare pixel precision of the multi-picture image information output by the picture mixer with pixel precision of the output picture information in the multi-picture output information, and when the two are inconsistent, the multi-picture image information is correspondingly sampled Transmitting the multi-picture image information obtained by sampling to the image data output unit through the data bus; otherwise, outputting the multi-picture image information directly to the image data output unit;

And an image data output unit, configured to output image information to the encoding module.

A video service system, comprising: a multipoint control unit MCU, wherein the MCU is configured to connect to a plurality of user terminals through a network, and receive a handover request message including a screen display mode sent by the user terminal, and Determining a required screen mixer according to the screen display mode, and outputting a screen image corresponding to the requested screen display mode to the user terminal transmitting the switching request message; the screen display mode is for indicating the number of sub-screens displayed on the screen.

The system according to claim 15, wherein the MCU plays the video menu prompt information to the user terminal that sends the handover request message before receiving the handover request message.

The system according to claim 15, wherein, when the video service is initialized, the MCU specifies a default picture mixer for multi-picture combination; during the video service, the MCU is selected according to the user. The screen display mode determines the desired screen mixer.

The system according to claim 17, wherein, in the process of performing a video service, the MCU dynamically modifies the default picture mixer according to the number of user terminals participating in the video service. Attribute information.

The system according to any one of claims 15 to 18, wherein the MCU comprises: a control module, configured to manage multi-screen control information, and play video menu prompt information to a user terminal participating in the video service, And dynamically determining the screen mixer according to the screen display mode selected by the user;

The system according to claim 19, wherein the control module records related information of the sub-picture image that needs the frame identification to the picture mixer, and the picture mixer completes the multi-picture combination and the sub-picture The picture image is marked with the edge ^ I.