System and method for synchronizing vehicle media playback apparatuses

Abstract

Provided is a method for synchronizing vehicle media playback apparatuses. The method comprises the steps of: synchronizing a system timer between a plurality of vehicle media playback apparatuses; and synchronizing, on the basis of the synchronized system timer and media playback time point information, media playback time points of the plurality of vehicle media playback apparatuses, wherein, in the step of synchronizing the system timer between the plurality of vehicle media playback apparatuses, the system timer is synchronized on the basis of unidirectional communication delay information between the plurality of vehicle media playback apparatuses and synchronization setting delay information for the system timer.

Description

Synchronization system and method for vehicle media playback device

[0001] The present invention relates to a synchronization system and method for a vehicle media playback device.

[0002] Vehicles are equipped with multiple Rear Seat Entertainment (RSE) systems. Each RSE system can provide different functions to different users. However, sometimes, multiple RSE systems are used simultaneously to watch media, such as news, movies, and dramas.

[0003] In these situations, if each device shares specific content and plays it simultaneously without using a mirroring solution, synchronization issues may arise. This can lead to lip sync issues, where audio and video do not match between devices, even when viewing the same video.

[0004] Even when playback commands are sent simultaneously to different devices or in different virtualization or container environments within the same device (e.g., a unified cockpit), the timing at which the media players within each device or container execute the commands may differ due to network latency, system load, scheduling-related delays, etc.

[0005] Due to differences in the absolute system time values ​​of the systems on which each media player operates, this problem may not be resolved by a simple synchronization system alone.

[0006] Addressing this requires sophisticated synchronization and timing control mechanisms, which can involve complex algorithms and technologies that take into account network conditions and system conditions.

[0007] The problem to be solved by the present invention is to provide a synchronization system and method for a vehicle media playback device that can improve user convenience by resolving synchronization problems that occur when sharing and simultaneously playing media between multiple media playback devices in a vehicle.

[0008] However, the problems to be solved by the present invention are not limited to the problems described above, and other problems may exist.

[0009] A method performed by a synchronization system for a vehicle media playback device according to a first aspect of the present invention for solving the above-described problem includes the steps of: synchronizing system timers between a plurality of vehicle media playback devices; and synchronizing media playback times of the plurality of vehicle media playback devices based on the synchronized system timers and media playback time information. In this case, the step of synchronizing the system timers between the plurality of vehicle media playback devices synchronizes the system timers based on one-way communication delay information between the plurality of vehicle media playback devices and synchronization setting delay information of the system timers.

[0010] In some embodiments of the present invention, the step of synchronizing system timers between the plurality of vehicle media playback devices may include the step of transmitting current first time information of a first vehicle media playback device to a second vehicle media playback device and requesting a response; the step of receiving a response to the transmission from the second vehicle media playback device; and the step of generating the one-way communication delay information based on the current second time information of the first vehicle media playback device and the first time information.

[0011] In some embodiments of the present invention, the step of synchronizing the system timers between the plurality of vehicle media playback devices may include: a step of reflecting the one-way communication delay information in current third time information of the first vehicle media playback device and transmitting the same to the second vehicle media playback device; a step of synchronizing and setting the system timer based on third time information in which the one-way communication delay information is reflected in the second vehicle media playback device; a step of transmitting current fourth time information to the first vehicle media playback device when the synchronization setting of the system timer is completed in the second vehicle media playback device; and a step of reflecting the fourth time information and the one-way communication delay information and generating the synchronization setting delay information based on current fifth time information in which the fourth time information is received in the first vehicle media playback device.

[0012] In some embodiments of the present invention, the step of synchronizing the system timers between the plurality of vehicle media playback devices may include: a step of reflecting the one-way communication delay information and the synchronization setting delay information in the current sixth time information of the first vehicle media playback device and transmitting the same to the second vehicle media playback device; a step of setting the system timer in synchronization based on the sixth time information in which the one-way communication delay information and the synchronization setting delay information are reflected in the second vehicle media playback device; a step of transmitting current seventh time information to the first vehicle media playback device when the synchronization setting of the system timer in the second vehicle media playback device is completed; and a step of terminating the synchronization of the system timer when the current eighth time information, which received the seventh time information in the first vehicle media playback device, is within a preset error range of the seventh time information reflecting the one-way communication delay information.

[0013] In some embodiments of the present invention, the step of synchronizing the media playback time of the plurality of vehicle media playback devices may include the step of determining whether a time corresponding to the playback time information has arrived based on the synchronized system timer; and the step of simultaneously playing the media on the plurality of vehicle media playback devices when the time has arrived as a result of the determination.

[0014] In addition, a synchronization system for a vehicle media playback device according to a second aspect of the present invention includes a first vehicle media playback device that plays media based on a first container in a virtual environment, and a second vehicle media playback device that plays media based on a second container in the virtual environment. At this time, the first vehicle media playback device synchronizes the system timers of the first and second vehicle media playback devices based on one-way communication delay information between the first and second vehicle media playback devices and synchronization setting delay information of the system timer, and synchronizes the media playback times of the first and second vehicle media playback devices based on the synchronized system timers and media playback time information.

[0015] Some embodiments of the present invention may further include at least one RSE (Rear Seat Environment)-based third vehicle media playback device that is connected to the first and second vehicle media playback devices through a predetermined network and plays media.

[0016] In addition, a synchronization system for a vehicle media playback device according to a third aspect of the present invention includes a client-based first vehicle media playback device that receives and plays media through a streaming server, and a client-based second vehicle media playback device that receives and plays media through the streaming server. At this time, the first vehicle media playback device synchronizes the system timers of the first and second vehicle media playback devices based on one-way communication delay information between the first and second vehicle media playback devices and synchronization setting delay information of the system timer, and synchronizes the media playback times of the first and second vehicle media playback devices based on the synchronized system timers and media playback time information.

[0017] In some embodiments of the present invention, when the resource usage rate exceeds a preset value and continues for a certain period of time or accumulates for a certain period of time, the second vehicle media playback device requests the first vehicle media playback device to confirm a playback time including current time information and playback time information, and the first vehicle media playback device can compare the current time information and playback time information of the second vehicle media playback device and one-way communication delay information with the playback time and current time information of the first vehicle media playback device to determine whether synchronization is necessary.

[0018] In some embodiments of the present invention, when the first media playback device is a main device, the first media playback device may receive a resource usage rate of a container corresponding to each vehicle media playback device, generate media delay prediction information of each vehicle media playback device based on each resource usage rate, and determine whether to transmit a playback time confirmation request message to all or individual vehicle media playback devices based on the media delay prediction information.

[0019] In addition, a computer program according to another aspect of the present invention is coupled with a computer as hardware to execute a synchronization system and method for the vehicle media playback device, and is stored in a computer-readable recording medium.

[0020] Other specific details of the present invention are included in the detailed description and drawings.

[0021] According to the present invention described above, by synchronizing media playback between multiple media playback devices installed in a vehicle, a consistent media playback experience can be provided to the user. Synchronized media playback allows passengers in the vehicle to enjoy a consistent multimedia experience and resolves lip-sync issues, providing a better user experience.

[0022] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0023] FIG. 1 is a structural diagram of a synchronization system for a vehicle media playback device according to a first embodiment of the present invention.

[0024] FIG. 2 is a structural diagram of a synchronization system for a vehicle media playback device according to a second embodiment of the present invention.

[0025] FIG. 3 is a structural diagram of a synchronization system for a vehicle media playback device according to a third embodiment of the present invention.

[0026] Figure 4 is a flowchart of a synchronization method according to one embodiment of the present invention.

[0027] FIG. 5 is a flowchart for explaining a system timer synchronization process in one embodiment of the present invention.

[0028] FIG. 6 is a diagram for explaining a synchronization process between a media playback point and a system timer in one embodiment of the present invention.

[0029] FIG. 7 is a procedure diagram for explaining in more detail a system timer synchronization process according to one embodiment of the present invention.

[0030] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the present invention, and the present invention is defined solely by the scope of the claims.

[0031] The terminology used herein is for the purpose of describing embodiments only and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the mentioned components. Like reference numerals refer to like components throughout the specification, and "and / or" includes each and any combination of one or more of the mentioned components. Although "first", "second", etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, it should be understood that a first component mentioned below may also be a second component within the technical spirit of the present invention.

[0032] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0033] FIG. 1 is a structural diagram of a synchronization system (100) for a vehicle media playback device according to a first embodiment of the present invention.

[0034] A synchronization system (100) according to one embodiment of the present invention includes a first vehicle media playback device (110) and a second vehicle media playback device (120).

[0035] The first vehicle media playback device (110) plays media based on a first container (111) in a virtualized environment, and the second vehicle media playback device (120) plays media based on a second container (121) in the same virtualized environment.

[0036] Here, "media" refers to any visual or auditory information requiring synchronization. This may include video and audio, but is not necessarily limited to these. Text and images can also be used, and a combination of these can be provided as media.

[0037] According to one embodiment of the present invention, a synchronization system (100) operates in a virtualized environment in which each vehicle media player (110, 120) operates within a separate virtualized container (111, 121), and the containers (111, 121) provide a separate execution environment through virtual machine or container technology. Each container (111, 121) provides an isolated space so that an operating system and application programs can be independently executed, thereby enabling each vehicle media player to operate independently.

[0038] Meanwhile, in the description of the first embodiment of the present invention, the vehicle media playback device only describes the first and second vehicle media playback devices (110, 120), but this is for the convenience of explanation. That is, the embodiment of the present invention is generally equipped with four vehicle media playback devices (in the case of a passenger car) as illustrated in FIG. 1, but of course, more than that may be equipped depending on the size of the vehicle and the number of passengers, such as an SUV or a van.

[0039] One embodiment of the present invention is characterized in that the system timer is synchronized based on one-way communication delay information between the first and second vehicle media playback devices (110, 120) and synchronization setting delay information of the system timer provided in each vehicle media playback device. In general, each container (111, 121) can use the system timer of the host operating system, but in this case, there may be a problem that synchronization is not achieved during media playback between each vehicle media playback device (110, 120). Therefore, in one embodiment of the present invention, a system timer may be provided for each vehicle media playback device (110, 120) that operates through each container (111, 121).

[0040] Meanwhile, the entity that synchronizes the system timer may be any component, but depending on the embodiment, the system timer of another vehicle media playback device may be synchronized based on the system timer of one vehicle media playback device. For convenience of explanation, the entity that performs the synchronization is referred to as the first vehicle media playback device (110), and the object whose system timer is synchronized is referred to as the second vehicle media playback device (120).

[0041] When the synchronization of the system timer for each vehicle media playback device is completed, the first vehicle media playback device (110) synchronizes the media playback times of the first and second vehicle media playback devices (110, 120) based on the synchronized system timer and media playback time information.

[0042] FIG. 2 is a structural diagram of a synchronization system (100) for a vehicle media playback device according to a second embodiment of the present invention.

[0043] In the second embodiment of the present invention, the synchronization system (100) according to the first embodiment has an expanded structure. That is, one embodiment of the present invention may further include at least one RSE (Rear Seat Environment)-based third vehicle media playback device (130) that is connected to the first and second vehicle media playback devices (110, 120) through a predetermined network and plays media.

[0044] In the case of the second embodiment of the present invention, the RSE-based third vehicle media playback device (130) can share and play media through a network, and thus may have more difficulty performing media synchronization. This is because delays, mismatches in system timers, bandwidth, packet loss, etc. may occur due to the characteristics of the network, and one embodiment of the present invention enables accurate media synchronization by taking into account the network delay problem and the mismatch problems in system timers.

[0045] FIG. 3 is a structural diagram of a synchronization system (100) for a vehicle media playback device according to a third embodiment of the present invention.

[0046] The third embodiment of the present invention, unlike the first and second embodiments, has a structure in which media is provided to a streaming client (220) through a streaming server (210), and the streaming client (220) may be the first and second vehicle media playback devices.

[0047] The first vehicle media playback device receives and plays media through a streaming server (210), and the second vehicle media playback device also receives and plays media through the same streaming server (210).

[0048] At this time, the first and second vehicle media playback devices can be synchronized based on the system timer of the streaming server (210), and the other vehicle media playback device can also be synchronized based on the system timer of one vehicle media playback device.

[0049] Hereinafter, a method performed by a synchronization system (100) for a vehicle media playback device according to one embodiment of the present invention will be described with reference to FIGS. 4 to 7.

[0050] Figure 4 is a flowchart of a synchronization method according to one embodiment of the present invention. Figure 5 is a flowchart illustrating a system timer synchronization process according to one embodiment of the present invention. Figure 6 is a diagram illustrating a synchronization process between a media playback point and a system timer according to one embodiment of the present invention.

[0051] In one embodiment of the present invention, first, system timers between multiple vehicle media playback devices are synchronized (S110).

[0052] Referring to FIG. 5, one embodiment of the present invention can check one-way communication delay information between a plurality of vehicle media playback devices (S111), check synchronization setting delay information of a system timer and other additional delay information (S112), and then synchronize the system timer based on each delay information (S113).

[0053] Next, the media playback timing of multiple vehicle media playback devices is synchronized based on the synchronized system timer and media playback timing information (S120).

[0054] If each vehicle media playback device performs playback immediately upon transmitting a media playback command, synchronization cannot be achieved if there is a difference in the timing of command reception. Therefore, one embodiment of the present invention is characterized in that the playback command includes information specifying the playback time point to resolve the synchronization problem.

[0055] That is, the playback command includes a video offset indicating the time at which playback should begin, which represents the relative time from which media playback should begin. The playback command also includes a system time at which playback should begin. This is based on a synchronized system timer, allowing each vehicle's media playback device to operate based on a common time.

[0056] Each vehicle media playback device that receives a playback command does not immediately execute the playback command, but determines whether a time corresponding to the playback point information has been reached based on a synchronized system timer (S121). If the determination result has been reached, multiple vehicle media playback devices play the media simultaneously (S122).

[0057] One embodiment of the present invention can maintain synchronization between vehicle media playback devices and ensure accurate playback timing through information included in a playback command and setting a waiting time in this manner.

[0058] FIG. 7 is a procedure diagram for explaining in more detail a system timer synchronization process according to one embodiment of the present invention.

[0059] The system timer synchronization process, which is the S110 step described above, is described in more detail as follows.

[0060] First, the first vehicle media playback device transmits the current first time information to the second vehicle media playback device and requests a response (S1111). The second vehicle media playback device, upon receiving the request, immediately transmits a response to the transmission to the first vehicle media playback device (S1112). The first vehicle media playback device, upon receiving the response, can generate one-way communication delay information based on the current second time information and the first time information (S1113). At this time, the one-way communication delay information corresponds to a value obtained by halving the result of subtracting the first time information from the second time information.

[0061] Next, the first vehicle media playback device reflects the one-way communication delay information calculated prior to the current third time information and transmits it to the second vehicle media playback device (S1114).

[0062] The second vehicle media playback device that receives this performs synchronization settings for its own system timer based on the third time information that reflects the one-way communication delay information (S1115). At this time, performing the synchronization settings takes a considerable amount of time, and one embodiment of the present invention considers up to this time as delay information so that synchronization can be performed. After the synchronization setting of the system timer is completed, the second vehicle media playback device transmits the current fourth time information to the first vehicle media playback device (S1116).

[0063] Next, the first vehicle media playback device can generate synchronization setting delay information by reflecting the fourth time information and the one-way communication delay information based on the current fifth time information that received the fourth time information (S1117). That is, the synchronization setting delay information is a value obtained by subtracting the fourth time information and the one-way communication delay information from the fifth time information, and can obtain the time at which the second vehicle media playback device purely performed the synchronization setting of the system timer.

[0064] Next, the first vehicle media playback device reflects the one-way communication delay information and the synchronization setting delay information in the current 6th time information and transmits them to the second vehicle media playback device (S1118).

[0065] The second vehicle media playback device that received this performs synchronization of the system timer again based on the sixth time information that reflects the one-way communication delay information and the synchronization setting delay information (S1119). In the previous process, only the one-way communication delay information was reflected and the system timer was synchronized, but in this process, the one-way communication delay information and the synchronization setting delay information are reflected and the system timer is synchronized, which is different.

[0066] Next, as the synchronization setting of the system timer in the second vehicle media playback device is completed, the current 7th time information is transmitted to the first vehicle media playback device (S1120).

[0067] The first vehicle media playback device that received this reports that the synchronization of the system timer is completed and terminates the synchronization process when the current 8th time information, which received the 7th time information, is within a preset error range compared to the 7th time information reflecting the one-way communication delay information (S1121).

[0068] Meanwhile, the aforementioned process synchronizes media before playback. Depending on various circumstances, synchronization may be required during playback after the media has been played. This means that synchronization may vary slightly due to various factors, such as the performance, load, and network conditions of each vehicle's media playback device. While minor synchronization mismatches may be barely noticeable to the user, significant mismatches can lead to significant user inconvenience.

[0069] Accordingly, one embodiment of the present invention allows the first vehicle media playback device to periodically transmit a playback time confirmation request message to all vehicle media playback devices.

[0070] For example, a first vehicle media playback device may transmit its current time information to a second vehicle media playback device, and the second vehicle media playback device, which receives the current time information, may transmit its current time information and the corresponding playback point information of the media being played to the first vehicle media playback device. The first vehicle media playback device may compare its own playback point based on the playback point information, time information, and one-way communication delay information of the second vehicle media playback device, and if there is an error between each playback point, the first vehicle media playback device may transmit information to the second vehicle media playback device to synchronize the time by the amount of the error.

[0071] Alternatively, since the system load may be concentrated when the first vehicle media playback device determines whether synchronization with the remaining vehicle media playback devices is necessary, depending on the embodiment, multiple vehicle media playback devices may periodically transmit a playback time confirmation request message to each vehicle media playback device in charge.

[0072] In addition to or separately from periodically transmitting a playback point confirmation request message, each vehicle media playback device (second vehicle media playback device) may independently monitor resource usage, and if the resource usage exceeds a preset value for a predetermined period of time or accumulates for a predetermined period of time, transmit a playback point confirmation request message including its own current time information and playback point information to the first vehicle media playback device. Upon receiving this, the first vehicle media playback device may compare its own playback point and current time information by considering the current time information and playback point information of the second vehicle media playback device and one-way communication delay information, and then determine whether synchronization is necessary. That is, if the playback point difference is less than a threshold, synchronization may be determined not to be necessary, and if it exceeds the threshold, synchronization may be determined to be necessary.

[0073] Furthermore, one embodiment of the present invention can transmit the resource usage rate of a container corresponding to each vehicle media playback device to the main device. Here, the main device may be the first vehicle media playback device or may transmit the data to the integrated cockpit system. For example, the integrated cockpit system or the first vehicle media playback device may generate media delay prediction information for each vehicle media playback device based on the resource usage rate, and based on the media delay prediction information, determine whether to transmit a playback time confirmation request message to all vehicle media playback devices or individually, or adjust the cycle thereof together or separately. Here, the media delay prediction information may be generated based on performance information of each virtual machine. Meanwhile, the integrated cockpit system may be a synchronization system or may be configured separately. Accordingly, one embodiment of the present invention can maintain smooth synchronization of media playback by executing the synchronization cycle more frequently when the resource usage rate of a specific vehicle media playback device increases rapidly or the network condition deteriorates. Conversely, when the resource usage rate is stable and the network condition is good, the synchronization cycle can be relaxed to reduce system load.

[0074] Furthering the above-described embodiment, one embodiment of the present invention can configure multiple vehicle media playback devices into a single cluster, sharing media playback timing and resource usage rates within each cluster. More specifically, the first and second vehicle media playback devices can be configured into the same cluster, periodically exchanging the media playback timing and resource usage rates of each device.

[0075] At this time, the first vehicle media playback device and the second vehicle media playback device compare their respective playback point information. If the difference between the playback points of the two devices is within the allowable range set within the cluster, it is determined that no additional synchronization is necessary and playback can continue as is. Conversely, if the difference in playback points exceeds the allowable range, synchronization is determined to be necessary and the two devices can autonomously adjust the playback point. In this process, the first vehicle media playback device can act as a master and issue synchronization commands to the second vehicle media playback device. Conversely, the second vehicle media playback device can act as a master depending on resource utilization.

[0076] Additionally, when there is a vehicle media playback device with high resource utilization, other vehicle media playback devices in the cluster can supplement the resources of that device or send synchronization requests.

[0077] Meanwhile, one embodiment of the present invention is capable of synchronization not only between one cluster but also between multiple clusters by taking into account communication delay and resource status.

[0078] In addition, one embodiment of the present invention collects synchronization mismatch information from each vehicle media playback device over a unit period and determines whether the average synchronization mismatch information over multiple unit periods exceeds a preset threshold. If the determination result indicates that the average synchronization mismatch exceeds a preset threshold, additional resources may be allocated to the vehicle media playback device.

[0079] Here, the threshold can be determined in advance through testing as the time difference that a user can perceive as a synchronization mismatch on any one of the multiple vehicle media playback devices.

[0080] Furthermore, in one embodiment of the present invention, if the number of vehicle media playback devices exceeding a threshold exceeds a majority or a number according to a setting, additional resources may be allocated to each of the vehicle media playback devices in response to synchronization mismatch information.

[0081] This process can be repeated for multiple unit periods, and as this process is repeated, the entire vehicle media playback device can have its resource allocation optimized, thereby minimizing synchronization mismatch.

[0082] Meanwhile, in the above description, steps S110 to S122 may be further divided into additional steps or combined into fewer steps, depending on the implementation of the present invention. Furthermore, some steps may be omitted as needed, and the order of the steps may be changed. Furthermore, even if other details are omitted, the details described in FIGS. 1 to 3 and 4 to 7 are mutually applicable.

[0083] The synchronization system (100) and method for a vehicle media playback device in one embodiment of the present invention described above can be implemented as a program (or application) to be executed in combination with a computer as hardware and stored in a medium.

[0084] The above-described program may include codes coded in a computer language, such as C, C++, JAVA, Ruby, or machine language, that can be read by the processor (CPU) of the computer through the device interface of the computer, so that the computer reads the program and executes the methods implemented as a program. Such codes may include functional codes related to functions that define functions necessary to execute the methods, and may include control codes related to execution procedures necessary for the processor of the computer to execute the functions according to a predetermined procedure. In addition, such codes may further include memory reference-related codes regarding which location (address address) of the internal or external memory of the computer should reference additional information or media necessary for the processor of the computer to execute the functions. In addition, if the processor of the computer needs to communicate with any other computer or server located remotely in order to execute the functions, the code may further include communication-related code regarding how to communicate with any other computer or server located remotely using the communication module of the computer, and what information or media to send and receive during communication.

[0085] The above storage medium refers to a medium that stores data semi-permanently and can be read by a device, rather than a medium that stores data for a short period of time, such as a register, cache, or memory. Specifically, examples of the storage medium include, but are not limited to, ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage device. That is, the program can be stored in various recording media on various servers that the computer can access or in various recording media on the user's computer. In addition, the medium can be distributed across network-connected computer systems, so that computer-readable code can be stored in a distributed manner.

[0086] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0087] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. A method performed by a synchronization system for a vehicle media playback device, Step for synchronizing system timers between multiple vehicle media playback devices; and Comprising a step of synchronizing media playback times of the plurality of vehicle media playback devices based on the synchronized system timer and media playback time information, The step of synchronizing the system timer between the plurality of vehicle media playback devices comprises: Synchronizing the system timer based on the one-way communication delay information between the plurality of vehicle media playback devices and the synchronization setting delay information of the system timer. A synchronization method for a vehicle media playback device.

2. In paragraph 1, The step of synchronizing the system timer between the plurality of vehicle media playback devices comprises: A step of transmitting current first time information of a first vehicle media playback device to a second vehicle media playback device and requesting a response; A step in which the first vehicle media playback device receives a response to the transmission from the second vehicle media playback device; and A step of generating the one-way communication delay information based on the current second time information of the first vehicle media playback device and the first time information, A synchronization method for a vehicle media playback device.

3. In paragraph 2, The step of synchronizing the system timer between the plurality of vehicle media playback devices comprises: A step of reflecting the one-way communication delay information into the current third time information of the first vehicle media playback device and transmitting it to the second vehicle media playback device; A step for synchronizing and setting a system timer based on third time information reflecting the one-way communication delay information in the second vehicle media playback device; A step of transmitting the current fourth time information to the first vehicle media playback device upon completion of the synchronization setting of the system timer in the second vehicle media playback device; and Including a step of generating the synchronization setting delay information by reflecting the fourth time information and the one-way communication delay information based on the current fifth time information received from the first vehicle media playback device. A synchronization method for a vehicle media playback device.

4. In paragraph 3, The step of synchronizing the system timer between the plurality of vehicle media playback devices comprises: A step of reflecting the one-way communication delay information and the synchronization setting delay information into the current 6th time information of the first vehicle media playback device and transmitting it to the second vehicle media playback device; A step of synchronizing and setting a system timer based on sixth time information reflecting the one-way communication delay information and the synchronization setting delay information in the second vehicle media playback device; A step of transmitting the current 7th time information to the first vehicle media playback device upon completion of the synchronization setting of the system timer in the second vehicle media playback device; and Including a step of terminating synchronization of a system timer when the current 8th time information received from the 7th time information in the first vehicle media playback device is within a preset error range with the 7th time information reflecting the one-way communication delay information. A synchronization method for a vehicle media playback device.

5. In paragraph 1, The step of synchronizing the media playback time of the plurality of vehicle media playback devices is as follows. A step of determining whether a time corresponding to the playback point information has been reached based on the synchronized system timer; and Including a step of simultaneously playing media on the plurality of vehicle media playback devices when the above judgment result is reached. A synchronization method for a vehicle media playback device.

6. In a synchronization system for a vehicle media playback device, A first vehicle media playback device that plays media based on a first container in a virtualized environment, and Including a second vehicle media playback device that plays media based on a second container in the above virtualized environment, The first vehicle media playback device synchronizes the system timers of the first and second vehicle media playback devices based on one-way communication delay information between the first and second vehicle media playback devices and synchronization setting delay information of the system timer, and synchronizes the media playback times of the first and second vehicle media playback devices based on the synchronized system timers and media playback time information. Synchronization system for vehicle media playback devices.

7. In paragraph 6, Further comprising at least one RSE (Rear Seat Environment)-based third vehicle media playback device that is connected to the first and second vehicle media playback devices through a predetermined network and plays media. Synchronization system for vehicle media playback devices.

8. In a synchronization system for a vehicle media playback device, A client-based first vehicle media playback device that receives and plays media through a streaming server, A second vehicle media playback device based on a client receives and plays media through the streaming server, The first vehicle media playback device synchronizes the system timers of the first and second vehicle media playback devices based on one-way communication delay information between the first and second vehicle media playback devices and synchronization setting delay information of the system timer, and synchronizes the media playback times of the first and second vehicle media playback devices based on the synchronized system timers and media playback time information. Synchronization system for vehicle media playback devices.

9. In paragraph 8, The second vehicle media playback device requests the first vehicle media playback device to confirm the playback time including current time information and playback time information when the resource usage rate exceeds a preset value and continues for a certain period of time or accumulates for a certain period of time. The first vehicle media playback device compares the current time information and playback point information of the second vehicle media playback device and the one-way communication delay information with the playback point and current time information of the first vehicle media playback device to determine whether synchronization is necessary. Synchronization system for vehicle media playback devices.

10. In paragraph 8, If the above first media playback device is the main device, The first media playback device receives the resource usage rate of the container corresponding to each vehicle media playback device, generates media delay prediction information of each vehicle media playback device based on each resource usage rate, and determines whether to transmit a playback time confirmation request message to all or individual vehicle media playback devices based on the media delay prediction information. Synchronization system for vehicle media playback devices.

Images