A synchronization method and system for distributed video stitching

Abstract

The application provides a synchronization method and system of distributed video control, the synchronization method comprises the following steps: obtaining the input signal of the first distributed control unit connected with the input end, determining whether the first distributed control unit is a synchronization source unit or a following unit according to the input signal; if the first distributed control unit is the synchronization source unit, taking the clock signal of the first distributed control unit as the reference clock, generating the field synchronization signal, outputting the reference clock and the field synchronization signal to the second distributed control unit connected with the output end, and synchronizing the second distributed control unit according to the reference clock; if the first distributed control unit is the following unit, outputting the reference clock and the field synchronization signal forwarded by the first distributed control unit to the second distributed control unit connected with the output end to synchronize. The synchronization method and system of distributed video control provided by the application can realize expansion by adding a simple USB cascade line in the distributed control unit without a complex interaction protocol.

Description

Technical Field

[0001] This invention relates to the field of distributed image stitching technology, and in particular to a synchronization method and system for distributed video stitching. Background Technology

[0002] Currently, there are three main solutions for distributed control and control:

[0003] a) A large-scale, fixed-type video conferencing host based on a video conferencing processor. All display output cards are directly inserted into the video conferencing host. This video conferencing solution does not involve the networking relationship between video conferencing devices. Currently, most mainstream video conferencing processors on the market use this solution.

[0004] b) IP-based distributed video conferencing control schemes generally use 1588 protocol-type solutions. The video conferencing control unit of this scheme typically outputs only one video channel.

[0005] c) Synchronization scheme between multiple graphics cards: Short jumpers are used to transmit synchronization signals between multiple graphics cards, thereby ensuring absolute synchronization of the output of multiple graphics cards.

[0006] The above solution has the following drawbacks:

[0007] a) Fixed-type video conferencing control hosts have an inflexible structure and limited scale; generally, the maximum number of video interfaces cannot be expanded after the video conferencing processor leaves the factory; if expansion is desired, a complete redesign is required, including redesigning the hardware. Fixed-type video conferencing control hosts do not support video extension and are limited by the maximum length of the video cable.

[0008] b) Synchronization solutions based on the 1588 protocol involve complex protocols, are difficult to implement, and require specific switches; synchronization results are sometimes less than ideal, and most companies treat the specific implementation scheme as a company secret. Due to the processing capacity limitations of each control unit, 1588 protocol-based synchronization solutions are difficult to implement in ultra-large-scale networks.

[0009] c) The jumper method based on synchronization between graphics cards is not suitable for synchronization across devices because the cables are relatively long.

[0010] In video display systems, ensuring long-term alignment of the field synchronization signals output by multiple display controllers is challenging, especially for seamless LED screens. When field synchronization fails to align, horizontal or vertical lines appear on the screen, a phenomenon known as "screen alignment error." Furthermore, in the field of video splicing control, the design of control equipment becomes increasingly complex as the scale of the control network grows. Therefore, it is necessary to propose a simplified solution for large-screen splicing control, achieving lower equipment design and production costs and simplifying equipment networking. Summary of the Invention

[0011] This invention provides a synchronization method and system for distributed video splicing control, which solves the problem that it is difficult to maintain long-term alignment of the field synchronization signals output by multiple display splicing controllers in the prior art, and that the design of splicing control equipment becomes increasingly difficult as the scale of splicing control increases.

[0012] This invention provides a synchronization method for distributed video splicing control, applied to a USB cascade cable used as a serial cable between distributed splicing control units. The synchronization method includes:

[0013] The input signal of the first distributed splicing control unit connected to the input terminal is obtained, and the first distributed splicing control unit is determined to be a synchronization source unit or a follower unit based on the input signal;

[0014] If it is a synchronization source unit, the clock signal of the first distributed splicing control unit is used as the reference clock to generate a field synchronization signal. The reference clock and the field synchronization signal are output to the second distributed splicing control unit connected to the output terminal. The second distributed splicing control unit performs synchronization according to the reference clock and the field synchronization signal.

[0015] If it is a follower unit, the reference clock and field synchronization signal forwarded by the first distributed splicing control unit are output to the second distributed splicing control unit connected to the output terminal for synchronization.

[0016] Furthermore, determining whether the first distributed control unit is a synchronization source unit or a follower unit based on the input signal includes:

[0017] Determine whether a field synchronization signal exists in the input signal. If the field synchronization signal does not exist, the first distributed splicing control unit is a synchronization source unit; otherwise, the first distributed splicing control unit is a follower unit.

[0018] Furthermore, the clock signal of the first distributed control unit is used as a reference clock to generate a field synchronization signal, including:

[0019] The clock signal of the first distributed splicing control unit is used as a reference clock for the phase-locked loop to generate the horizontal and vertical synchronization signals of the locally displayed video.

[0020] Furthermore, it also includes:

[0021] If it is a follower unit, a reference clock is used as the reference clock for the phase-locked loop to generate the pixel clock and horizontal and vertical sync signals for display, wherein the horizontal and vertical sync signals are synchronized with the vertical sync signal on the cascaded line.

[0022] A distributed video splicing control synchronization system includes several distributed splicing control units and several USB cascade lines. The USB cascade lines serve as serial lines between two distributed splicing control units and are used to transmit a reference clock and field synchronization signal between the distributed splicing control units.

[0023] The distributed control unit is used as a synchronization source unit or a follower unit. The synchronization source unit uses its clock signal as a reference clock to generate a field synchronization signal and outputs the reference clock and the field synchronization signal to the follower unit. The follower unit synchronizes according to the reference clock and the field synchronization signal and forwards the received reference clock and field synchronization signal.

[0024] Furthermore, it also includes a KVM host, which is connected to the distributed control unit.

[0025] Furthermore, the distributed splicing control unit includes 8 fiber optic interfaces for establishing a set of 1 to 8 fiber optic interconnects with the KVM host to transmit a maximum of 8 video streams.

[0026] Furthermore, it also includes a large display screen, which is connected to the distributed splicing control unit.

[0027] Furthermore, the distributed splicing control unit includes eight DVI / HDMI interfaces, which can output up to eight video streams to the display screen.

[0028] The distributed video splicing control synchronization method and system provided by this invention can easily achieve capacity expansion by adding a simple USB cascading cable to the distributed splicing control unit without the need for complex interaction protocols. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a flowchart illustrating a distributed video splicing synchronization method according to an embodiment of the present invention;

[0031] Figure 2 This is a flowchart illustrating a distributed video splicing synchronization method according to another embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the structure of a distributed video splicing and control synchronization system provided in one embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of a distributed video splicing and control synchronization system provided in another embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] Figure 1 This is a flowchart illustrating a distributed video stitching synchronization method provided by the present invention. (Refer to...) Figure 1 This invention provides a synchronization method for distributed video splicing control, applied to a USB cascade cable used as a connection between distributed splicing control units, wherein the USB cascade cable is a serial cable, and the synchronization method includes:

[0036] S110, acquire the input signal of the first distributed splicing control unit connected to the input terminal, and determine the first distributed splicing control unit as a synchronization source unit or a follower unit based on the input signal.

[0037] S120, if it is a synchronization source unit, the clock signal of the first distributed splicing control unit is used as the reference clock to generate a field synchronization signal. The reference clock and the field synchronization signal are output to the second distributed splicing control unit connected to the output terminal. The second distributed splicing control unit synchronizes according to the reference clock and the field synchronization signal.

[0038] S130, if it is a follower unit, the reference clock and field synchronization signal forwarded by the first distributed splicing control unit are output to the second distributed splicing control unit connected to the output terminal for synchronization.

[0039] This application synchronizes the distributed splicing control units via a USB cascade cable. The USB cascade cable transmits reference signals between the distributed splicing control units without the need for complex interaction protocols, making it simple and easy to achieve synchronization. Compared with existing technologies, it has the advantages of simplified structure and good scalability.

[0040] Based on the above embodiments, as an optional embodiment, determining whether the first distributed control unit is a synchronization source unit or a follower unit according to the input signal includes:

[0041] Determine whether a field synchronization signal exists in the input signal. If the field synchronization signal does not exist, the first distributed splicing control unit is a synchronization source unit; otherwise, the first distributed splicing control unit is a follower unit.

[0042] This application embodiment uses a USB cascade cable to simultaneously transmit the field synchronization signal and the reference clock. Among several distributed splicing control units, only one synchronization source unit generates the field synchronization signal and the reference clock, while the other distributed splicing control units act as follower units, using the field synchronization signal and the reference clock as synchronization references. In existing video display systems, due to frequency deviation and temperature drift of the key component of each display control terminal—the crystal oscillator—it is difficult to ensure that the field synchronization signals output by multiple display splicing controllers remain aligned for a long time, especially for splicing control based on seamless LED screens. When field synchronization cannot be aligned, horizontal or vertical lines can be seen on the screen, i.e., the screen alignment phenomenon. However, this application embodiment only considers the clock and field synchronization signal of the synchronization source unit, using the crystal oscillator clock of the synchronization source unit as the synchronization reference clock for the phase-locked loop to generate the horizontal and vertical synchronization signals for the locally displayed video. Therefore, this application embodiment can solve the technical problem of being unable to achieve long-term alignment synchronization due to the frequency deviation and temperature drift of the crystal oscillator, ensuring the synchronization of splicing control.

[0043] Based on the above embodiments, as an optional embodiment, such as Figure 2 As shown, it includes:

[0044] If it is a synchronization source unit, the clock signal of the first distributed splicing control unit is output as a reference clock to the second distributed splicing control unit. Simultaneously, the vertical synchronization signal generated based on the reference clock is output to the second distributed splicing control unit. If it is a synchronization source unit, the first distributed splicing control unit uses a local crystal oscillator clock as a synchronization reference clock for the phase-locked loop to generate horizontal and vertical synchronization signals for the locally displayed video. Simultaneously, the local vertical synchronization signal and the local clock are output from the USB output terminal.

[0045] If it is a follower unit, the reference clock and vertical synchronization signal forwarded by the first distributed splicing control unit are output to the second distributed splicing control unit for synchronization. If it is a follower unit, the second distributed splicing control unit forwards the received vertical synchronization signal and reference clock. The synchronization of the second distributed splicing control unit specifically includes: using the reference clock as the reference clock of the phase-locked loop to generate a pixel clock and horizontal and vertical synchronization signals for display, wherein the horizontal and vertical synchronization signals are kept synchronized with the vertical synchronization signal on the cascaded line.

[0046] The embodiments of this application can solve the technical problem that the crystal oscillator cannot be aligned and synchronized for a long time due to frequency deviation and temperature drift, thus ensuring the synchronization of video splicing control.

[0047] The following describes the distributed video splicing control synchronization system provided by the present invention. The distributed video splicing control synchronization system described below can be referred to in correspondence with the distributed video splicing control synchronization method described above.

[0048] Figure 3 and Figure 4 These are schematic diagrams of a distributed video splicing and control synchronization system provided in two embodiments of the present invention, with reference to... Figure 3 and Figure 4 The present invention also provides a distributed video splicing control synchronization system, including several distributed splicing control units and several USB cascade lines, wherein the USB cascade lines serve as serial lines between two distributed splicing control units and are used to transmit a reference clock between the distributed splicing control units.

[0049] The distributed control unit is used as a synchronization source unit or a follower unit. The synchronization source unit uses its clock signal as a reference clock to generate a field synchronization signal and outputs the reference clock and the field synchronization signal to the follower unit. The follower unit synchronizes according to the reference clock and the field synchronization signal and forwards the received reference clock.

[0050] This application uses USB as a cascading cable to connect multiple splicing control units in series for synchronization. While ensuring the synchronous arrival of the video stream at each splicing control unit, the reference clock transmitted on the USB cable, combined with the field synchronization signal, achieves frame synchronization of the display between the various splicing control units. Compared with existing technologies, this method features a simplified structure and good scalability.

[0051] Furthermore, the synchronization source unit is also used to generate a field synchronization signal based on the reference clock. The USB cascade cable transmits the field synchronization signal, and the follower unit forwards the received field synchronization signal. This embodiment uses a USB cascade cable to simultaneously transmit the field synchronization signal and the reference clock. Among several distributed splicing control units, only one synchronization source unit generates the field synchronization signal and the reference clock; the other distributed splicing control units act as follower units, using the field synchronization signal and the reference clock as a synchronization reference. In existing video display systems, due to frequency deviation and temperature drift of the key component of each display control terminal—the crystal oscillator—it is difficult to ensure that the field synchronization signals output by multiple display splicing controllers remain aligned for a long time, especially in splicing control based on seamless LED screens. When the field synchronization cannot be aligned, horizontal or vertical lines can be seen on the screen, i.e., a screen array phenomenon. This embodiment, however, only considers the time reference clock and field synchronization signal of the synchronization source unit, using the crystal oscillator clock of the synchronization source unit as the synchronization reference clock for the phase-locked loop to generate the horizontal and vertical synchronization signals for the locally displayed video. Therefore, the embodiments of this application can solve the technical problem that the crystal oscillator cannot be aligned and synchronized for a long time due to frequency deviation and temperature drift, thus ensuring the synchronization of the splicing control.

[0052] Furthermore, it also includes a KVM host, which is connected to the distributed video conferencing control unit. Specifically, the distributed video conferencing control unit includes eight fiber optic interfaces for establishing a set of 1 to 8 fiber optic interconnects with the KVM host, transmitting a maximum of eight video streams. The distributed video conferencing control unit includes eight fiber optic interfaces, which improves the flexibility of the number of video stream transmission channels.

[0053] Furthermore, it also includes a large display screen, which is connected to the distributed splicing control unit. Specifically, the distributed splicing control unit includes eight DVI / HDMI interfaces, capable of outputting up to eight video streams to the large display screen. The inclusion of eight DVI / HDMI interfaces in the distributed splicing control unit improves the flexibility of the number of video stream outputs. In addition, by appropriately increasing the number of distributed splicing control units while reducing the number of video streams output by each unit, the effect of multiple layers can be achieved, further enhancing splicing control flexibility.

[0054] The large display screen can include two modes: DLP large screen splicing control and LED large screen splicing control. The USB cascading cable is used to connect multiple distributed splicing control units in series, and the jumper wires transmit the field synchronization signal and reference clock signal. Distributed splicing control unit 1 acts as the synchronization source unit, and the other distributed splicing control units act as follower units. The synchronization source unit sends the reference field synchronization signal and reference clock to the downstream follower units, and the follower units forward the received field synchronization signal and reference clock signal, and so on. Distributed splicing control units 1 and N have only one jumper wire interconnected with the other units in the series, while display splicing control units 2 to N-1 have two jumper wires interconnected with the upstream and downstream units. In the USB output direction of any distributed splicing control unit, as long as the splicing control unit is displaying normally, the field synchronization signal and reference clock signal can be captured; specifically, this can be captured using an oscilloscope.

[0055] The distributed video splicing control synchronization method and system provided by this invention can easily achieve capacity expansion by adding a simple USB cascading cable to the distributed splicing control unit without the need for complex interaction protocols.

[0056] Simplified structure: The distributed control units only require simple USB jumpers and do not need to implement complex interaction protocols, making implementation easier and debugging simpler.

[0057] Good scalability: The scale of the display splicing control is easy to expand. Using more distributed splicing control units can achieve a larger scale of splicing control. In principle, there is no limit to the number of distributed splicing control units. It is very easy to expand the capacity of existing display splicing control large screens.

[0058] High flexibility: By appropriately increasing the number of distributed splicing control units and reducing the number of video output channels of each distributed splicing control unit, the effect of multiple layers can be achieved.

[0059] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, flash chip, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A synchronization method for distributed video wall control, the method comprising: The application is applied to a USB cascade line between distributed control units, the USB cascade line is a serial line, the USB cascade line simultaneously transmits a field synchronization signal and a reference clock, only one of a plurality of distributed control units is a synchronization source unit generating the field synchronization signal and the reference clock, and other distributed control units are follower units using the field synchronization signal and the reference clock as a reference for synchronization, and the synchronization method comprises the following steps: An input signal of a first distributed control unit connected to an input end is acquired, and it is determined whether the first distributed control unit is a synchronization source unit or a follower unit according to the input signal; If the first distributed control unit is the synchronization source unit, a clock signal of the first distributed control unit is used as the reference clock, a field synchronization signal is generated, and the reference clock and the field synchronization signal are output to a second distributed control unit connected to an output end, and the second distributed control unit is synchronized according to the reference clock and the field synchronization signal; If the first distributed control unit is the follower unit, the reference clock and the field synchronization signal forwarded by the first distributed control unit are output to the second distributed control unit connected to the output end for synchronization.

2. The method of Claim 1, wherein, The step of determining whether the first distributed control unit is the synchronization source unit or the follower unit according to the input signal comprises the following steps: It is determined whether the input signal contains the field synchronization signal, if the input signal does not contain the field synchronization signal, the first distributed control unit is the synchronization source unit, otherwise, the first distributed control unit is the follower unit.

3. The method of Claim 2, wherein, The step of using the clock signal of the first distributed control unit as the reference clock to generate the field synchronization signal comprises the following steps: The clock signal of the first distributed control unit is used as the reference clock for a phase-locked loop, and a line field synchronization signal of a locally displayed video is generated.

4. The method of Claim 2, wherein, The step of using the clock signal of the first distributed control unit as the reference clock to generate the field synchronization signal comprises the following steps: If the first distributed control unit is the follower unit, a reference clock is used as a reference clock of a phase-locked loop to generate a pixel clock and a line field synchronization signal for display, and the line field synchronization signal and the field synchronization signal on the cascade line are kept synchronized.

5. A synchronization system for distributed video wall control, the system comprising: The application comprises a plurality of distributed control units and a plurality of USB cascade lines, the USB cascade line is a serial line between two distributed control units, and is used for transmitting a reference clock and a field synchronization signal between the distributed control units; only one of the plurality of distributed control units is a synchronization source unit generating the field synchronization signal and the reference clock, and other distributed control units are follower units using the field synchronization signal and the reference clock as a reference for synchronization. The distributed control unit is used as the synchronization source unit or the follower unit, the synchronization source unit uses a clock signal thereof as a reference clock, generates a field synchronization signal, and outputs the reference clock and the field synchronization signal to the follower unit, and the follower unit is synchronized according to the reference clock and the field synchronization signal and forwards the received reference clock and field synchronization signal.

6. The system of claim 5, wherein, The application further comprises a KVM host connected to the distributed control unit.

7. The synchronized system of distributed video wall control of claim 6, wherein, The distributed control unit comprises eight optical fiber interfaces, which are used for establishing a group of 1-8-way optical fiber interconnections with the KVM host, and transmitting a maximum of 8-way video code streams.

8. The system of claim 5, wherein, The application further comprises a large screen connected to the distributed control unit.

9. The system of claim 8, wherein, The distributed control unit includes 8 DVI / HDMI interfaces, and outputs 8 video streams to the display screen at most.

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