JP6361012B2 - Playback system and playback method - Google Patents

Description

  The present invention relates to a playback system and a playback method.

  There are playback devices that play back content including images or sounds. The playback device plays back an image or sound based on image data or sound data stored in a storage device in the playback device or received via a network. In addition, a plurality of the above playback devices may be installed, and each playback device may play back the same content. Since the same content is played by a plurality of playback devices, the viewing effect of the user can be enhanced.

  Patent Document 1 discloses a technique for synchronizing content reproduction timing between a content transmitting device (master device) and a content receiving device (slave device).

Japanese Patent No. 5418033

  However, when each of a plurality of playback devices plays back the same content, the playback timing may not be uniform due to individual differences in hardware among the playback devices or differences in processing load. If the playback timing is not aligned, the user's viewing effect cannot be improved.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a reproduction system and the like that suppress a deviation in reproduction timing for each reproduction apparatus.

  In order to solve the above problems, a playback system according to an aspect of the present invention is a playback system including a synchronization device and a plurality of playback devices, and the synchronization device is a time in an hour, minute, and second format indicating a current time. A time management unit that manages information, a first counter management unit that increases the first counter value at a predetermined time interval, and the time information and the first counter value at the same time point, respectively, synchronization time information and synchronization A transmission unit that transmits as a counter value, and each of the plurality of playback devices acquires a content acquisition unit that acquires content, and (i) acquires the synchronization time information and the synchronization counter value transmitted by the transmission unit. (Ii) an acquisition unit that acquires target time information in an hour, minute, and second format that indicates a time at which the content should be reproduced; and a second counter value is increased at the predetermined time interval. A second counter management unit configured to set the synchronization counter value to the second counter value; and a differential counter value corresponding to a differential time determined by the target time information and the synchronization time information. (A) When the second counter value is smaller than the calculated target counter value, the second counter value is added to the calculated target counter value. (B) When the second counter value is not smaller than the calculated target counter value, control is performed from the target counter value to the second counter value. Control for reproducing the content from a position advanced from the beginning of the content for a time corresponding to the calculated increase amount. Cormorants, and a reproduction control unit.

  According to this, a plurality of playback devices can play back content in synchronization with each other. Each playback device receives time information and a counter value necessary for synchronous playback from the synchronization device, and determines a content playback timing based on the received time information and the counter value. Each playback device uses a counter value that increases at the same time interval by design to determine the playback timing based on the same reference. Therefore, the playback timing shift across multiple playback devices is suppressed and synchronized (others). Content can be played back at the same playback timing as that of the playback device. In addition, a playback device that starts playback with a delay while content is being played back by another playback device starts playback from the same frame as the frame being played back by the other playback device. Therefore, the playback system can suppress a shift in playback timing for each playback device.

  The content acquisition unit acquires a plurality of content files and a playlist indicating the playback order of the plurality of content files as the content, and the playback control unit acquires the plurality of content files in the playback order. When the second counter value is not smaller than the calculated target counter value, the content is reproduced by playing, and when the second counter value is not smaller than the calculated target counter value, the control is performed for the time corresponding to the calculated increase amount. A content file and a position in the content file corresponding to a position advanced from the start of reproduction in the reproduction order are identified, and the identified content file is reproduced from the identified position.

  According to this, when the content is composed of a plurality of content files, the playback device specifies the content file to be played and then plays the content file from an appropriate frame. Therefore, even if the content is composed of a plurality of content files, the playback device can appropriately suppress a shift in playback timing for each playback device.

  The reproduction control unit performs control to repeatedly reproduce the content. When the second counter value is not smaller than the calculated target counter value, the reproduction control unit corresponds to the calculated increase amount in the control. A position in the content corresponding to a position advanced from the start of the repeated reproduction for the time is specified, and the content is reproduced from the specified position.

  According to this, when the content is repeatedly played back, the playback device specifies a frame to be played back in consideration of the repeated playback. Therefore, even if the content is repeatedly reproduced, the reproduction device can appropriately suppress a deviation in reproduction timing for each reproduction device.

  The acquisition unit further holds specific information for specifying the synchronization time information to be acquired and a synchronization device that is a transmission source of the synchronization counter value, and the specific information is different from that of the synchronization device. When the specific information of the synchronization device is changed, the synchronization time information and the synchronization counter value transmitted by the transmission unit of the other synchronization device are acquired, and the reproduction control unit acquires the synchronization acquired from the other synchronization device. A new increase amount is calculated using the time information and the synchronization counter value, and the content is reproduced.

  According to this, when the synchronization device that is the transmission source of the information for synchronization is changed, the playback device again specifies the frame to be played back of the content. When the synchronization device is changed, the synchronization time information and the synchronization counter value are changed, so it is necessary to change the frame to be reproduced. Therefore, the playback system can suppress a shift in playback timing for each playback device.

  In addition, the acquisition unit acquires a second playlist after acquiring the first playlist that is the playlist, and the reproduction control unit determines that the second playlist is different from the first playlist. Is the content file shown in the second playlist corresponding to the position advanced from the start of playback in the playback order shown in the second playlist for the time corresponding to the calculated increase amount in the control And the position in the content file are identified, and the identified content file is reproduced from the identified position.

  According to this, when the playlist is changed, the playback device specifies again the frame to be played back of the content. When the playlist is changed, the content file itself to be reproduced can be changed, or the position to be reproduced in the content file can be changed, so that the frame to be reproduced needs to be changed. Therefore, the playback system can suppress a shift in playback timing for each playback device.

  A playback method according to an aspect of the present invention is a playback method in a playback system including a synchronization device and a plurality of playback devices, and the synchronization device manages time information in an hour / minute / second format indicating a current time. A time management step, a first counter management step in which the synchronization device increases a first counter value at a predetermined time interval, and the synchronization device has the time information and the first counter value at the same time point, Each of the plurality of playback devices acquires a content, and each of the plurality of playback devices includes (i) the transmission. Obtaining the synchronization time information and the synchronization counter value transmitted in the step, and (ii) indicating the time at which the content should be reproduced An acquisition step of acquiring second time target time information; and a second counter management step in which each of the plurality of playback devices increases a second counter value at the predetermined time interval, and the second counter value is set to the second counter value. A second counter management step for setting the synchronization counter value, and each of the plurality of playback devices adds a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value (A) when the second counter value is smaller than the calculated target counter value, when the second counter value matches the calculated target counter value, And (b) when the second counter value is not smaller than the calculated target counter value, the target is reproduced. A playback control step of calculating an increase amount from an uncounter value to the second counter value and performing playback control of the content from a position advanced from the top of the content for a time corresponding to the calculated increase amount; Including.

  Thereby, there exists an effect similar to the said reproduction | regeneration system.

  The reproduction system according to the present invention can suppress a deviation in reproduction timing for each reproduction apparatus.

FIG. 1 is a network configuration diagram of the reproduction system according to the first embodiment. FIG. 2 is a block diagram illustrating a hardware configuration of the synchronization device according to the first embodiment. FIG. 3 is a block diagram showing a hardware configuration of the playback apparatus according to the first embodiment. FIG. 4 is a functional block diagram of the reproduction system according to the first embodiment. FIG. 5 is an explanatory diagram of a notification packet according to the first embodiment. FIG. 6 is a flowchart of the reproduction system according to the first embodiment. FIG. 7 is an explanatory diagram of the synchronized playback according to the first embodiment. FIG. 8 is a functional block diagram of the reproduction system according to the second embodiment. FIG. 9 is an explanatory diagram of a content reproduction method according to the second embodiment. FIG. 10 is an explanatory diagram of a method for continuously synchronizing according to the second embodiment. FIG. 11 is an explanatory diagram of the first configuration of the third embodiment. FIG. 12 is an explanatory diagram of the second configuration of the third embodiment. FIG. 13 is a functional block diagram of the playback apparatus according to the fourth embodiment. FIG. 14 is a flowchart of the playback system according to the fourth embodiment. FIG. 15 is an explanatory diagram of the synchronized playback according to the fourth embodiment. FIG. 16 is an explanatory diagram of a playlist according to the fourth embodiment. FIG. 17 is an explanatory diagram of a method for calculating a specific position of a content file according to the fourth embodiment. FIG. 18 is an explanatory diagram of a specific position in the case of repeated reproduction according to the fourth embodiment.

  Hereinafter, embodiments will be specifically described with reference to the drawings.

  Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements that constitute a more preferable embodiment.

  In addition, the same code | symbol is attached | subjected to the same component and description may be abbreviate | omitted.

(Embodiment 1)
In the present embodiment, a playback system or the like that suppresses a shift in playback timing for each playback device will be described.

  FIG. 1 is a configuration diagram of a reproduction system 1 according to the present embodiment.

  As shown in FIG. 1, the playback system 1 includes a synchronization device 10, playback devices 20A and 20B, and display devices 25A and 25B. The synchronization device 10 and the playback devices 20A and 20B can communicate with each other via the LAN 30.

  The synchronization device 10 is a device that transmits predetermined information for synchronized playback by the playback devices 20A and 20B to the playback devices 20A and 20B.

  The reproduction apparatus 20A is an apparatus that reproduces content based on predetermined information for synchronous reproduction received from the synchronization apparatus 10. Note that the content played back by the playback device 20A may be content stored in advance in a storage device in the playback device 20A, or content stored in a portable storage device connected to the playback device 20A. There may be. Further, the content may be one that has been received and stored from another device or storage medium via a network by the playback device before the playback time point.

  Similar to the playback device 20A, the playback device 20B is a device that plays back content. Note that the playback devices 20A and 20B may be collectively referred to as the playback device 20.

  The display devices 25A and 25B are display devices that display images based on image signals transmitted from the playback devices 20A and 20B, respectively. Note that the playback device 20A and the display device 25A may be collectively referred to as a playback device.

  The playback device 20A and the playback device 20B can play back the content in synchronization by playing back the content based on the predetermined information received from the synchronization device 10.

  FIG. 2 is a block diagram showing a hardware configuration of the synchronization device according to the present embodiment.

  As shown in FIG. 2, the synchronization device 10 includes an ST 101 (Software Timer), a control unit 102, a NIC 103 (Network Interface Card), and an HT 104 (Hardware Timer), which are interconnected inside. .

  ST101 is a timer that manages time information in an hour, minute, and second format that indicates the current time. The time information in the hour, minute, and second format is time information in a format that expresses the time using the unit of year, month, day, hour, minute, and second, such as “January 1, 2001 1:01:01”. It is. ST101 manages time information by adding a numerical value indicating time information every predetermined time interval (for example, 0.01 seconds). Note that the minimum unit of time in the time information in the hour / minute / second format is not necessarily “1 second”. For example, the minimum unit can be 0.01 seconds. When the minimum unit is 0.01 seconds, time information in units of hours, minutes, and seconds may be expressed as “January 1, 2001 1:01:01”.

  The control unit 102 has a function of controlling the overall operation of the synchronization device 10. Specifically, the control unit 102 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.

  The NIC 103 is a communication interface that transmits communication data to the LAN 30 or receives communication data from the LAN 30. The NIC 103 may be a wired LAN interface that conforms to the IEEE 802.3 standard or the like, or may be a wireless LAN interface that conforms to the IEEE 802.11a, b, g, or n standard.

  The HT 104 is a counter that increases the counter value at a predetermined time interval. The predetermined time interval does not change with the passage of time by design, but in reality, there may be some fluctuations with the passage of time. The HT 104 increases the counter value with a time length smaller than the minimum time unit in the time information managed by the ST 101. The time interval at which the HT 104 increases the counter value is, for example, 0.01 milliseconds. When the minimum unit of time of ST101 is 0.01 seconds, the minimum unit of ST101 is 1000 times the minimum unit of HT104.

  In addition, a slight time difference may occur between the HTs 104 in a plurality of playback apparatuses due to individual differences in hardware.

  FIG. 3 is a block diagram showing a hardware configuration of the playback apparatus according to the present embodiment.

  As shown in FIG. 3, the playback device 20 includes an ST 201, a control unit 202, a NIC 203, an HT 204, a playback unit 205, and a storage device 206, which are interconnected inside.

  ST 201, control unit 202, NIC 203, and HT 204 have the same functions as components of the same name in synchronization device 10.

  The playback unit 205 plays back content. Specifically, the playback unit 205 generates an image or audio signal to be output based on content data stored in the storage device 206. Further, the reproduction unit 205 may output the generated image or audio signal by a display device (not shown) or a speaker (not shown), or may output the signal to another device. When the content data has been subjected to processing such as compression or encoding, the playback unit 205 performs the playback after performing the corresponding processing such as decompression or decoding.

  The storage device 206 is a storage device that stores content data including images or sounds. The content is composed of a plurality of still images or a moving image (a set of still images related to each other). In the above content, the relative playback time of each frame is determined using a counter value (relative counter value). The relative counter value is expressed by, for example, a difference between the counter values from the first frame of the content. Note that audio (audio data) can also be handled in the same manner as the image (image data) in the above description.

  Note that the storage device 206 is not an essential component. The storage device 206 may be a portable storage device that is detachably connected to the playback device 20.

  FIG. 4 is a functional block diagram of the playback system according to the present embodiment.

  As illustrated in FIG. 4, the synchronization device 10 includes a time management unit 111, a counter management unit 112, and a transmission unit 113. In addition, the playback device 20 includes an acquisition unit 211, a counter management unit 212, a content acquisition unit 213, and a playback control unit 214.

  The time management unit 111 manages time information in the hour / minute / second format indicating the current time. Specifically, time management section 111 manages time information using ST101 which is a timer. In addition, the time management unit 111 acquires time information managed by the ST 101 and provides the acquired time information to the transmission unit 113. In providing, when the signal which requests | requires time information is received, you may provide according to a request | requirement and you may provide regularly and spontaneously. The time management unit 111 is realized by ST101 and the like.

  The counter management unit 112 increases the counter value at a predetermined time interval. Specifically, the counter management unit 112 manages the counter value using the HT 104 that is a counter. In addition, the counter management unit 112 acquires the counter value of the HT 104 and provides the acquired counter value to the transmission unit 113. As with the time management unit 111 described above, when providing a signal requesting a counter value, it may be provided in response to a request, or may be provided periodically and voluntarily. The counter management unit 112 corresponds to a first counter management unit. Further, the counter value of the counter management unit 112 corresponds to the first counter value.

  The transmission unit 113 transmits the time information managed by the time management unit 111 and the counter value managed by the counter management unit to the playback device 20 at the same time point. Here, the time information and counter value to be transmitted are also referred to as synchronization time information and synchronization counter value, respectively.

  The transmission unit 113 acquires time information from the time management unit 111 and acquires a counter value from the counter management unit 112 substantially simultaneously. Here, the term “substantially simultaneously” includes a case where the time is strictly the same and a case where there is a time difference that is not exactly the same but is recognized as simultaneous by human senses. In the following, similar expressions may be used.

  Further, the transmission unit 113 transmits the synchronization time information and the synchronization counter value to the playback device 20 via the LAN 30. For example, the transmission unit 113 transmits a notification packet describing the above information by sending it to the LAN 30. An example of the notification packet will be described in detail later.

  The acquisition unit 211 acquires the synchronization time information and the synchronization counter value transmitted by the transmission unit 113. In addition, the acquisition unit 211 acquires target time information in an hour, minute, and second format that indicates a time at which content is to be reproduced.

  Specifically, the acquisition unit 211 acquires the synchronization time information and the synchronization counter value transmitted from the transmission unit 113 by receiving via the LAN 30. Moreover, the acquisition part 211 acquires what is designated by the user as target time information. The method for acquiring the target time information is not particularly limited. For example, when the playback device 20 has an interface for accepting an operation by a user, the playback device 20 can acquire target time information through the interface. Further, the playback device 20 can also be acquired from the synchronization device 10 or another device (not shown) operated by the user via the LAN 30.

  The counter management unit 212 increases the counter value at a predetermined time interval. The time interval at which the counter management unit 212 increases the counter value is identical in design to the time interval at which the counter management unit 112 increases the counter value.

  Further, when the acquisition unit 211 acquires the synchronization counter value, the counter management unit 212 sets the acquired synchronization counter value as the counter value, and then increases the counter value from the set counter value. Note that the counter management unit 212 corresponds to a second counter management unit, and the counter value increased by the counter management unit 212 corresponds to a second counter value.

  The content acquisition unit 213 acquires content. Here, the location from which the content acquisition unit 213 acquires content is not limited. For example, the content acquisition unit 213 may acquire content from the storage device 206, may acquire content from a storage medium connected to the playback device 20, or may acquire from other devices via the LAN 30. May be.

  The reproduction control unit 214 calculates a target counter value by adding a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value, and adds the calculated counter value to the counter management unit 212. The content is controlled to be played back when the counter values managed by each match.

  Specifically, when the synchronization time information is STbase, the synchronization counter value is HTbase, and the target time information is STstart, the playback control unit 214 sets the counter value HC to the target counter value HTstart determined by (Equation 1). The above control is performed when they match.

  HTstart = HTbase + ΔHT (Formula 1)

  Here, ΔHT is a counter value difference (difference counter value) corresponding to a difference time (ΔST) determined by the target time information and the synchronization time information, and is defined by (Expression 2) and (Expression 3). Here, C is a constant indicating the ratio of the difference of the counter value to the difference time of the time information.

ΔHT = ΔST × C (Formula 2)
ΔST = STstart−STbase (Formula 3)

  The playback control unit 214 performs the above processing for each frame. In this case, it is possible to efficiently determine the playback time using the relative playback time in the content of each frame. The method will be described in detail separately.

  FIG. 5 is an explanatory diagram of a notification packet according to the present embodiment.

  FIG. 5 is an example of a notification packet transmitted by the transmission unit 113, and is an example of a notification packet configured by a UDP (User Datagram Protocol) packet.

  In the UDP payload of the notification packet 501, synchronization time information (STbase) and a synchronization counter value (HTbase) are described. In the UDP header, a UDP port number for exchanging notification packets is set in the destination UDP port number. In the IP (Internet Protocol) header and the MAC (Media Access Control) header, a broadcast or multicast address is set as the destination IP address and the destination MAC address. This is because the plurality of playback devices 20A and 20B connected to the LAN 30 receive the same packet.

  The notification packet is not limited to that shown in FIG. The notification packet only needs to be able to notify the plurality of playback devices 20 (acquisition unit 211) of the synchronization time information and the synchronization counter value from the synchronization device 10 (transmission unit 113). Therefore, instead of describing the synchronization time information and the synchronization counter value in the same packet, for example, the synchronization time information and the synchronization counter value may be described in each of the two packets and sequentially transmitted. Further, a unicast packet designating a destination of each of a plurality of playback devices may be sequentially transmitted to each playback device without setting a broadcast or multicast address. Further, the synchronization time information and the synchronization counter value may be described in the IP payload or the MAC payload instead of the UDP payload.

  FIG. 6 is a flowchart of the playback system according to the present embodiment. FIG. 7 is an explanatory diagram of synchronized playback according to the present embodiment. With reference to FIGS. 6 and 7, a method of synchronized playback of the playback system 1 will be described.

  In step S611, time management section 111 acquires time information indicating the current time from ST101. In addition, the counter management unit 112 acquires a counter value from the HT 104. For example, “08:55:00” is acquired as the time information and “100” is acquired as the counter value (FIG. 7).

  In step S612, the transmission unit 113 transmits the time information acquired by the time management unit 111 in step S611 and the counter value acquired by the counter management unit 112 to the playback device 20 as synchronization time information and a synchronization counter value, respectively. To do. At the time of transmission, for example, the transmission unit 113 broadcasts and transmits a notification packet 501 describing the synchronization time information and the synchronization counter value.

  In step S621, the content acquisition unit 213 acquires content.

  In step S622, the acquisition unit 211 acquires target time information.

  In step S623, the acquisition unit 211 acquires the synchronization time information and the synchronization counter value transmitted by the transmission unit 113 of the synchronization device 10 in step S612. When the notification packet is used for transmission of the synchronization time information and the synchronization counter value, the acquiring unit 211 acquires the synchronization time information and the synchronization counter value by receiving the notification packet.

  In step S624, the counter management unit 212 sets the synchronization counter value acquired by the acquisition unit 211 in step S623 as the counter value. For example, when the counter value before setting is “202” and the counter value is “100”, the counter management unit 212 sets the counter value to 100 (FIG. 7).

  In step S625, the reproduction control unit 214 calculates the target counter value HTstart using the above (Expression 1) to (Expression 3). For example, when the target time is “09:00:00” and the constant C is 1000, the target counter value HTstart = 600100 (FIG. 7).

  In step S626, the reproduction control unit 214 reproduces the content when the counter value managed by the counter management unit 212 matches the target counter value HTstart. Specifically, the reproduction control unit 214 monitors the counter value managed by the counter management unit 212, and reproduces the content when the counter value reaches the target counter value 600100.

  Note that the playback device 20 (playback control unit 214) has a function of performing not only control for playing back the content acquired by the content acquisition unit 213, but also control for playing back streaming content distributed from the streaming server. Also good.

  Specifically, a case is assumed where a streaming server (not shown) is connected to the LAN 30 and the streaming server distributes streaming content to the playback device 20 via the LAN 30. In the playback apparatus 20, the NIC 203 receives the streaming content, and the playback control unit 214 plays back the received streaming content.

  In this case, the playback device 20 may appropriately switch between playing back the content acquired by the content acquisition unit 213 or receiving streaming content. For example, switching may be performed depending on whether or not streaming content is received. Specifically, the reproduction control unit 214 performs control to reproduce the received streaming content when receiving the streaming content distributed from the streaming server, and the content acquisition unit 213 acquires when the streaming content is not received. You may make it perform control which reproduces the content which carried out. In this way, the content acquired by the content acquisition unit can be used as backup content when streaming content is not distributed.

  As described above, according to the reproduction system according to the present embodiment, a plurality of reproduction apparatuses can reproduce content in synchronization with each other. Each playback device receives time information and a counter value necessary for synchronous playback from the synchronization device, and determines a content playback timing based on the received time information and the counter value. Since each playback device determines the playback timing based on the same reference using a counter value that increases at the same time interval in design, it is possible to suppress a shift in playback timing across a plurality of playback devices. Therefore, the playback system can suppress a shift in playback timing for each playback device.

(Embodiment 2)
In the present embodiment, a description will be given of a playback system or the like that suppresses a shift in playback timing for each playback device when playing back content composed of a plurality of frames.

  The configuration of the reproduction system according to the present embodiment is the same as that of the reproduction system 1 according to the first embodiment. The hardware configurations of the synchronization device and the playback device are the same as those of the synchronization device 10 and the playback device 20 of the first embodiment, respectively.

  FIG. 8 is a functional block diagram of the playback system according to the present embodiment.

  As shown in FIG. 8, the playback system 2 includes a synchronization device 11 and a playback device 21.

  The synchronization device 11 includes a time management unit 111, a counter management unit 112, and a transmission unit 123. In addition, the playback device 21 includes an acquisition unit 211, a counter management unit 212, a content acquisition unit 223, and a playback control unit 224. The same functional blocks as those in Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

  The transmission unit 123 transmits the time information managed by the time management unit 111 and the counter value managed by the counter management unit to the playback device 21 at a plurality of timings. Specifically, a series of processes of obtaining time information, obtaining a counter value, and transmitting a notification packet describing the obtained time information and the counter value described in the first embodiment are performed at a plurality of timings. . Note that the time interval between the plurality of timings may be constant or may not be constant.

  The content acquisition unit 223 acquires content. The content acquired by the content acquisition unit 223 includes a plurality of frames. In the content, the relative playback time of each frame in the content is determined using a counter value (relative counter value). The relative counter value is expressed by, for example, a difference between the counter values from the first frame of the content. Note that it is possible to acquire each of a plurality of frames at a time or sequentially.

  The reproduction control unit 224 determines a reference counter value that is increased from the synchronization counter value by a difference time determined by the target time information and the synchronization time information. Then, for each of a plurality of frames included in the content, the counter value managed by the counter management unit 212 matches the target counter value obtained by increasing the relative counter value determined for each frame from the determined reference counter value. When doing so, control is performed to reproduce the frame.

  FIG. 9 is an explanatory diagram of a content reproduction method according to the present embodiment.

  As shown in FIG. 9A, it is assumed that the content is composed of (n + 1) frames from frame 0 to frame n. In addition, a relative counter value HTn is assigned to each frame. Specifically, relative counter value HT0 = 0 is assigned to frame 0, and relative counter value HT1 = 3 is assigned to frame 1.

  A method for reproducing each frame will be described with reference to FIG.

  First, the reproduction control unit 224 acquires target time information and synchronization time information by the same method as the reproduction control unit 214 in the first embodiment. Then, the reproduction control unit 224 determines a reference counter value HTstart that is increased from the synchronization counter value by the difference time between the target time information and the synchronization time information (HTstart = 600100 in FIG. 9B). The reference counter value corresponds to the target counter value in the first embodiment.

  Next, the playback control unit 224 calculates a counter value CHTn that indicates the time at which each of the frames included in the content is played back. CHTn is calculated by adding the relative counter value HTn of each frame to the target counter value HTstart. For example, as shown in FIG. 9B, CHT0 = 600100 and CHT1 = 600103 are calculated.

  Then, the reproduction control unit 224 reproduces the frame when the counter value managed by the counter management unit 212 matches each CHTn of the frame.

  In addition, when there are a plurality of playback apparatuses designed based on the same specification, a phenomenon may occur in which playback timings of images played back by the plurality of playback apparatuses are shifted after a relatively long time. One of the causes is that the time intervals for increasing the counter value of the HT 104 in a plurality of playback devices are not exactly the same. A method for avoiding this phenomenon will be described below.

  FIG. 10 is an explanatory diagram of a method for continuously synchronizing according to the present embodiment.

  As shown in FIG. 10, the synchronization device 11 periodically transmits a counter value HC (HC1, HC2,...) To the reproduction device 21. Specifically, the counter management unit 112 of the synchronization device 11 acquires a counter value from the HT 104, and the transmission unit 123 transmits the acquired counter value as HC.

  Further, the synchronization device 11 periodically sends the synchronization time information and the synchronization counter value ((STbase1, HTbase1), (STbase2, HTbase2), to the playback device 21 at intervals longer than the transmission interval of the counter value HC,.・ ・) Is sent. Specifically, the time management unit 111 of the synchronization device 11 acquires time information from ST101, the counter management unit 112 acquires a counter value from the HT104, and transmits the acquired time information and counter value as STbase and HTbase, respectively. The unit 123 transmits.

  As described above, the synchronization device 11 periodically transmits the counter value HC, so that the shift between the HT 104 of the synchronization device 11 and the HT 204 between the playback device 21 can be suppressed. Further, the synchronization device 11 periodically transmits the time information and the counter value, so that the reproduction timing adjustment in the reproduction device 21 is performed using the relatively new (relatively past) synchronization time information and the synchronization counter value. It can be performed.

(Embodiment 3)
In the present embodiment, modifications of the first and second embodiments will be described.

  FIG. 11 is an explanatory diagram of the first configuration of the present embodiment (first modification of the first and second embodiments).

  The playback system 3 shown in FIG. 11 includes four playback devices 20A, 20B, 20C, and 20D. Then, the playback devices 20A and 20B synchronously play back the first content by the display devices 25A and 25B, respectively, and the playback devices 20C and 20D have the second different from the first content by the display devices 25C and 25D, respectively. Play content synchronously.

  Thus, according to the playback system in the present embodiment, it is also possible to play back two or more pieces of content synchronously on a plurality of playback devices.

  FIG. 12 is an explanatory diagram of the second configuration of the present embodiment (the second modification of the first and second embodiments).

  The playback system 4 shown in FIG. 12 includes two playback devices 20E and 20B. Further, the playback device 20E includes the synchronization device 10 therein. Note that it can be said that the playback device 20E has the function of the synchronization device 10 in addition to the function of the playback device in each embodiment. The playback device 20E is also expressed as having both functions of the playback device and the synchronization device.

  The playback device 20E can synchronize the playback timing of the content by its own device and the playback timing of the content by the playback device 20B by the function of the synchronization device 10.

  When the playback device 20E has the functions of the playback device and the synchronization device, it is possible to share a common hardware configuration and reduce manufacturing costs or operation costs.

(Embodiment 4)
In the present embodiment, for a playback system that suppresses a shift in playback timing for each playback device, the playback timing shift is further reduced when another playback device newly starts playback during playback of content by the playback device. A method of suppressing will be described. Note that the reproduction system in the present embodiment is referred to as a reproduction system 5 (not shown).

  FIG. 13 is a functional block diagram of the playback device 22 according to the present embodiment.

  As shown in FIG. 13, the playback device 22 includes an acquisition unit 211, a counter management unit 212, a content acquisition unit 213, and a playback control unit 214A. Among these, the acquisition unit 211, the counter management unit 212, and the content acquisition unit 213 are the same as the components having the same names in the first embodiment, and thus the description thereof is omitted.

  The playback control unit 214A controls playback of content. The playback control unit 214A determines the timing for starting playback of the content and the position at which playback starts (playback position in the content) according to the determination result by the determination unit 215.

  The determination unit 215 determines whether the counter value managed by the counter management unit 212 is smaller than the target counter value. As in the first embodiment, the target counter value is calculated by adding a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value. When the counter value is smaller than the target counter value, it means that the current time point is before (past) the time point at which the reproduction of the content is to be started, and it is only necessary to start the reproduction of the content after the current time point. On the other hand, when the counter value is not smaller than the target counter value (that is, larger or equal), the current time point is after the time point at which the reproduction of the content is to be started, and another reproduction device (hereinafter, simply “ This means that another content playback device "has already started playing the content. Note that “first” is a concept indicating the past from the reference time, and “after” is a concept indicating the future from the reference time.

  When the determination unit 215 determines that the counter value managed by the counter management unit 212 is smaller than the target counter value, the reproduction control unit 214A matches the target counter value and the counter value managed by the counter management unit 212. When performing, control is performed to reproduce the content from the beginning of the content. On the other hand, when the determination unit 215 determines that the counter value managed by the counter management unit 212 is not smaller than the target counter value, the reproduction control unit 214A calculates an increase amount from the target counter value to the counter value. Then, control is performed to reproduce the content from a position advanced from the top of the content for a time corresponding to the calculated increase amount. The “time corresponding to the increase” is also referred to as a specific time, and the position is also referred to as a specific position.

  Note that the reproduction control unit 214A and the determination unit 215 may perform the above process again when the synchronization device that has transmitted the synchronization time information and the synchronization counter value acquired by the acquisition unit 211 is changed. In this case, for example, the acquisition unit 211 holds specific information for specifying the synchronization time information acquired by the acquisition unit 211 and the synchronization device that is the transmission source of the synchronization counter value, and this specific information, that is, the synchronization device is changed. In this case, the reproduction control unit 214A and the determination unit 215 may perform the above process again based on the newly acquired synchronization time information and the synchronization counter value.

  In the above description, the configuration in which the playback control unit 214A includes the determination unit 215 has been described. However, the playback control unit 214A itself may include the function of the determination unit 215.

  FIG. 14 is a flowchart of the reproduction system 5 according to the present embodiment. FIG. 15 is an explanatory diagram of synchronized playback according to the present embodiment. With reference to FIG. 14 and FIG. 15, a method of synchronized playback of the playback system 5 will be described.

  Since the processing of steps S611 and S612 by the synchronization device 10 and the processing of steps S621 to S625 by the playback device 22 are the same as the processing steps of the same name in the first embodiment, description thereof will be omitted.

  In step S630, the determination unit 215 determines whether the counter value managed by the counter management unit 212 is smaller than the target counter value calculated in step S625. In the above determination, if it is determined that the counter value at the local point is smaller than the target counter value (Yes in step S630), the process proceeds to step S631. On the other hand, when it is determined that the counter value at the local point is not smaller than the target counter value (No in step S630), the process proceeds to step S632.

  In step S631, when the counter value managed by the counter management unit 212 matches the target counter value HTstart, the reproduction control unit 214A reproduces the content from the beginning of the content. This process is substantially the same as the process of step S624 in the first embodiment.

  In step S632, the reproduction control unit 214A calculates a specific time and a specific position, and starts content from the specific position. Specifically, when the target time is “09:00:00” and the current time (ST) is “09: 0: 30”, the specific time and the specific position are (Formula 5) and ( It is calculated as in equation 6).

Specific time = 09: 0: 30 (ST) -09: 00: 00 (target time)
= 00: 00: 30 (Formula 5)
Specific position = specific time × C
= 30000 (Formula 6)

  The specific position can also be directly calculated as in (Expression 7) using the counter value managed by the counter management unit 212 and the target counter value.

Specific position = 630100 (counter value) −600100 (target counter value)
= 30000 (Formula 7)

  In this way, the reproduction control unit 214A reproduces the content from the frame at the position advanced by 30000 counters from the top of the content (10000th frame from the top of the content). Here, the “position advanced 30000 counters from the beginning of the content” means a position advanced from the beginning of the content by the time required for the counter value to increase by 30000. In the following, the same expression is used.

  As described above, when the playback control unit 214A plays back the content, the other playback devices play back frames at a position advanced by 30000 counters from the top of the content. Therefore, after another playback device has already started playing the content (while playing the content), the playback device that newly starts playing the content plays the same frame as the other playback device. become. As a result, all the playback devices of the playback system 5 are in a state of playing back the same frame.

  Next, a description will be given of a method for specifying a playback position when content is composed of a plurality of content files (hereinafter also simply referred to as files). In the following description, it is assumed that one content is composed of a plurality of content files, and the reproduction order of the plurality of contents is determined by the playlist. That is, reproducing a plurality of contents in the order shown in the playlist corresponds to reproducing one content described above.

  FIG. 16 is an explanatory diagram of the playlist 1601 according to the present embodiment. FIG. 17 is an explanatory diagram of a method for calculating a specific position of a content file according to the present embodiment.

  The playlist 1601 shown in FIG. 16 is information indicating the playback order of a plurality of content files, and each piece of information on the content file name 1611, playback time 1612, and relative time 1613 from the top of the playlist for each content file. A plurality of entries including are included. A plurality of content files and a playlist 1601 correspond to one content.

  The content file name 1611 is a character string (for example, “0002”) indicating the name of the content file. Other content file names 1611 may be used as long as the content file can be uniquely identified.

  The reproduction time 1612 is information indicating the reproduction time of the content file indicated by the entry. For example, the reproduction time 1612 is indicated by a time such as 5 seconds, or is indicated by a counter width such as 5000 counter. .

  The relative time 1613 from the top of the playlist is the time from the playback start time of the first content file to the playback time of the content file indicated by the entry when the content files are played back in the order shown in the playlist. is there.

  When the content acquisition unit 213 acquires a plurality of content files and playlists as the content, the reproduction control unit 214A performs control to reproduce the plurality of content files in the order according to the playlist. Here, when the counter value managed by the counter management unit 212 is not smaller than the target counter value, the reproduction control unit 214A starts reproduction in the reproduction order for the time corresponding to the calculated increase amount. The content file corresponding to the advanced position and the position in the content file are specified, and the specified content file is reproduced from the specified position.

  As shown in FIG. 17, when the content is composed of a plurality of content files, when the specific position is calculated as 30000 (counter) by (Equation 6), the playback control unit 214A refers to the playlist. Thus, it is specified which content file includes the position advanced by 30000 counters from the top of the playlist, and what number frame in the content corresponds to the specified content file. Play content from a frame. Specifically, the content file “0003” is specified as the content file including the position advanced by 30000 counters from the top of the playlist, and the 15000th frame is specified as the frame in the content.

  When the content acquisition unit 213 acquires a new playlist (corresponding to the second playlist), the playback control unit 214A and the determination unit 215 specify a frame to be played back based on the new playlist. You may do it.

  As described above, the playback control unit 214A can play back content from an appropriate position even when the content is composed of a plurality of content files.

  Next, a method for specifying a playback position when content is repeatedly played back will be described. The repeated reproduction is to reproduce the content from the beginning again after reproducing the content to the end and to repeat this.

  FIG. 18 is an explanatory diagram of a specific position in the case of repeated playback according to the present embodiment.

  As shown in FIG. 18, the playback device 22 repeatedly plays back content whose playback time is 90 seconds.

  At this time, the playback control unit 214A performs control to repeatedly play back the content. If the counter value managed by the counter management unit 212 is not smaller than the target counter value, the playback control unit 214A repeatedly performs the time corresponding to the increase amount. A position in the content corresponding to the position advanced from the start of reproduction is specified, and the content is reproduced from the specified position.

  Specifically, the playback control unit 214A takes into account that, when the content is repeatedly played back and the specific time is calculated as 200 seconds according to (Equation 6), the playback control unit 214A considers that the playback is being repeated, and the playlist The content to be identified by specifying which content file includes the frame to be played back at the time of 200 seconds from the start of playback of the content, and what number frame in the content corresponds to Play content from the specified frame of the file. Specifically, the point in time of 200 seconds from the start of content playback is calculated as the time point of 20 seconds from the start of the third playback, based on (Equation 8) during the third repeated playback.

  200 ÷ 90 = 2 more than 20 (Formula 8)

  The frame to be reproduced at this point is a frame 20 seconds after the start of the third content reproduction, that is, a frame at a position advanced 20000 (= 20 × C) from the top of the content. Further, this frame is a frame at a position advanced 5000 counters from the top of the content file “0003” in consideration of the playlist 1601.

  As described above, the reproduction control unit 214A can reproduce the content from an appropriate position even when the content is repeatedly reproduced.

  As described above, the plurality of playback devices according to the present embodiment can play back content in synchronization with each other. Each playback device receives time information and a counter value necessary for synchronous playback from the synchronization device, and determines a content playback timing based on the received time information and the counter value. Each playback device uses a counter value that increases at the same time interval by design to determine the playback timing based on the same reference. Therefore, the playback timing shift across multiple playback devices is suppressed and synchronized (others). Content can be played back at the same playback timing as that of the playback device. In addition, a playback device that starts playback with a delay while content is being played back by another playback device starts playback from the same frame as the frame being played back by the other playback device. Therefore, the playback system can suppress a shift in playback timing for each playback device.

  In addition, when the content is composed of a plurality of content files, the reproduction device identifies the content file to be reproduced and then reproduces the content file from an appropriate frame. Therefore, even if the content is composed of a plurality of content files, the playback device can appropriately suppress a shift in playback timing for each playback device.

  In addition, when the content is repeatedly played, the playback device specifies a frame to be played back in consideration of the repeated playback. Therefore, even if the content is repeatedly reproduced, the reproduction device can appropriately suppress a deviation in reproduction timing for each reproduction device.

  Further, when the synchronization device that is the transmission source of the information for synchronization is changed, the playback device specifies again the frame to be played back of the content. When the synchronization device is changed, the synchronization time information and the synchronization counter value are changed, so it is necessary to change the frame to be reproduced. Therefore, the playback system can suppress a shift in playback timing for each playback device.

  In addition, when the playlist is changed, the playback device again specifies a frame to be played back of the content. When the playlist is changed, the content file itself to be reproduced can be changed, or the position to be reproduced in the content file can be changed, so that the frame to be reproduced needs to be changed. Therefore, the playback system can suppress a shift in playback timing for each playback device.

  The playback system of the present invention has been described above based on the embodiment, but the present invention is not limited to this embodiment. Unless it deviates from the meaning of this invention, the form which carried out the various deformation | transformation which those skilled in the art can think to this embodiment, and the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .

  In addition, although a part or all of said embodiment may be described also as follows, it is not limited to the following description.

  (1) A playback system including a synchronization device and a plurality of playback devices, wherein the synchronization device includes a time management unit that manages time information in an hour / minute / second format indicating a current time, and a first time interval at a predetermined time interval. A plurality of playback devices, comprising: a first counter management unit that increases a counter value; and a transmission unit that transmits the time information and the first counter value at the same time as the synchronization time information and the synchronization counter value, respectively. Each of: a content acquisition unit for acquiring content; (i) acquiring the synchronization time information and the synchronization counter value transmitted by the transmission unit; and (ii) an hour, minute, and second indicating a time at which the content should be played back An acquisition unit that acquires target time information in a format, and a second counter management unit that increases a second counter value at the predetermined time interval, the second counter value being the same as the second counter value. Calculating a target counter value by adding a second counter management unit for setting a counter value and a differential counter value corresponding to a differential time determined by the target time information and the synchronous time information to the synchronous counter value; And a playback control unit that controls to play back the content when the second counter value matches the target counter value.

  (2) The playback system according to (1), wherein each of the plurality of playback devices further includes a storage unit that stores the content, and the content acquisition unit acquires the content from the storage unit.

  (3) The content includes a plurality of frames, and each of the plurality of frames has a relative counter value indicating a relative time point at which the frame is to be played back. i) calculating a reference counter value increased from the synchronization counter value by a difference time determined by the target time information and the synchronization time information; and (ii) determining each of the plurality of frames in the frame. A target counter value obtained by increasing the relative counter value from the reference counter value, and (iii) control for reproducing the frame when the second counter value matches the calculated target counter value. The reproduction system according to (1) or (2).

  (4) The transmission unit transmits the synchronization time information and the synchronization counter value at a plurality of timings, and the acquisition unit acquires the synchronization counter value transmitted by the transmission unit every time the acquisition unit acquires the synchronization counter value. The reproduction system according to (3), wherein the synchronization counter value is set to the second counter value of the second counter management unit.

  (5) The reproduction control unit performs control to reproduce the received streaming content when receiving streaming content distributed from a streaming server, and reproduces the content when the streaming content is not received. The reproduction system according to any one of (1) to (4).

  (6) The reproduction system according to any one of (1) to (5), wherein the predetermined time interval is shorter than a time interval in which the time management unit updates the time information.

  (7) A playback device in a playback system including a synchronization device and a plurality of playback devices, wherein the synchronization device includes a time management unit that manages time information in an hour / minute / second format indicating a current time, and a predetermined time interval. A first counter management unit that increments the first counter value, and a transmission unit that transmits the time information and the first counter value at the same time as the synchronization time information and the synchronization counter value, respectively. A device for acquiring a content; (i) acquiring the synchronization time information and the synchronization counter value transmitted by the transmission unit; and (ii) an hour / minute / second format indicating a time at which the content is to be reproduced An acquisition unit for acquiring the target time information, and a second counter management unit for increasing the second counter value at the predetermined time interval, wherein the second counter value is the same as the second counter value. Calculating a target counter value by adding a second counter management unit for setting a counter value and a differential counter value corresponding to a differential time determined by the target time information and the synchronous time information to the synchronous counter value; And a playback control unit that controls playback of the content when the second counter value matches the target counter value.

  (8) A playback method in a playback system including a synchronization device and a plurality of playback devices, in which the synchronization device manages time information in hour / minute / second format indicating a current time, and the synchronization device The first counter management step for increasing the first counter value at a predetermined time interval, and the synchronization device at the same time point, the time information and the first counter value as the synchronization time information and the synchronization counter value, respectively. A transmission step of transmitting, a content acquisition step of acquiring content by each of the plurality of playback devices, and (i) the synchronization time information and the synchronization counter transmitted by each of the plurality of playback devices in the transmission step. (Ii) an acquisition step for acquiring target time information in an hour / minute / second format indicating a time at which the content is to be reproduced; And a second counter management step in which each of the plurality of playback devices increases the second counter value at the predetermined time interval, and the second counter value is set to the second counter value. A counter management step, and each of the plurality of playback devices calculates a target counter value by adding a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value. A reproduction control step of performing a control to reproduce the content when the second counter value matches the calculated target counter value.

  According to (1) above, a plurality of playback devices can play back content in synchronization with each other. Each playback device receives time information and a counter value necessary for synchronous playback from the synchronization device, and determines a content playback timing based on the received time information and the counter value. Each playback device uses a counter value that increases at the same time interval by design to determine the playback timing based on the same reference. Therefore, the playback timing shift across multiple playback devices is suppressed and synchronized (others). Content can be played back at the same playback timing as that of the playback device. Therefore, the playback system can suppress a shift in playback timing for each playback device.

  According to (2) above, each playback device can play back the content stored in the storage unit by each playback device in synchronization with the other playback devices.

  According to the above (3), each playback device can play back each of the plurality of frames included in the content in synchronization with the other playback devices. Since each playback device determines the playback timing of each frame using the relative counter value defined for each of the plurality of frames included in the content, the playback timing of each of the plurality of frames is set to be different from that of other playback devices. Can be matched.

  According to (4) above, each playback device periodically receives the synchronization counter value from the synchronization device and sets it to the counter value of its own device. Therefore, even when the increasing time interval slightly fluctuates with the passage of time, each playback device can continuously match the counter value with the synchronization device and other playback devices. The playback timing can be synchronized.

  According to the above (5), each playback device can switch whether to play the streaming content or the content acquired by the content acquisition unit, depending on whether the streaming content is received or not. . Further, since each playback device plays back streaming content preferentially, the content acquired by the content acquisition unit can be used as backup content in the case where the streaming content is not distributed.

  According to the above (6), each playback device determines the playback timing using the counter value updated in a cycle shorter than the update cycle of the time information, so that the playback timing can be synchronized more accurately.

  According to said (7), there exists an effect similar to said reproduction | regeneration system.

  According to said (8), there exists an effect similar to said reproduction | regeneration system.

  The present invention can be used in a reproduction system that suppresses a deviation in reproduction timing for each reproduction apparatus. Specifically, a plurality of such devices can be installed in a public space or a commercial facility, and can be used for a playback device that plays back images and the like.

1, 2, 3, 4, 5 Playback system 10, 11 Synchronizer 20, 20A, 20B, 20C, 20D, 20E, 21, 22 Playback device 25A, 25B, 25C, 25D Display device 30 LAN
101, 201 ST
102, 202 Control unit 103, 203 NIC
104, 204 HT
111 Time management unit 112, 212 Counter management unit 113, 123 Transmission unit 205 Playback unit 206 Storage device 211 Acquisition unit 213, 223 Content acquisition unit 214, 214A, 224 Playback control unit 215 Determination unit

Claims (6)

A playback system comprising a synchronization device and a plurality of playback devices,
The synchronization device includes:
A time management unit for managing time information in an hour, minute and second format indicating the current time;
A first counter management unit for increasing the first counter value at a predetermined time interval;
A transmission unit that transmits the time information and the first counter value at the same time as the synchronization time information and the synchronization counter value, respectively;
Each of the plurality of playback devices is
A content acquisition unit for acquiring content;
(I) acquiring the synchronization time information and the synchronization counter value transmitted by the transmission unit; (ii) acquiring target time information in an hour / minute / second format indicating a time at which the content is to be reproduced;
A second counter management unit configured to increase a second counter value at the predetermined time interval, wherein the second counter management unit sets the synchronous counter value to the second counter value;
A target counter value is calculated by adding a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value;
(A) When the second counter value is smaller than the calculated target counter value, when the second counter value matches the calculated target counter value, control is performed to reproduce the content from the beginning.
(B) When the second counter value is not smaller than the calculated target counter value, an increase amount from the target counter value to the second counter value is calculated, and a time corresponding to the calculated increase amount A playback control unit that controls playback of the content from a position advanced from the beginning of the content ,
The reproduction control unit performs control to reproduce the content repeatedly,
In the case where the second counter value is not smaller than the calculated target counter value, in the control, in the content corresponding to the position advanced from the start of the repeated reproduction by the time corresponding to the calculated increase amount A playback system that specifies the position of the content and plays back the content from the specified position . The content acquisition unit acquires a plurality of content files and a playlist indicating a reproduction order of the plurality of content files as the content,
The reproduction control unit
Playing back the content by playing the plurality of content files in the playback order,
If the second counter value is not smaller than the calculated target counter value, it corresponds to a position advanced from the start of reproduction in the reproduction order by the time corresponding to the calculated increase amount in the control. The playback system according to claim 1, wherein a content file and a position in the content file are specified, and the specified content file is played from the specified position. The acquisition unit further includes:
The synchronization time information to be acquired and the specific information for specifying the synchronization device that is the transmission source of the synchronization counter value are held, and the specific information is changed to the specific information of another synchronization device different from the synchronization device The synchronization time information and the synchronization counter value transmitted by the transmission unit of the other synchronization device,
The reproduction control section uses the synchronization time information and the synchronization counter value acquired from the second synchronization device to calculate a new increase, according to claim 1 or 2 performs control to reproduce the content Playback system. A playback system comprising a synchronization device and a plurality of playback devices,
The synchronization device includes:
A time management unit for managing time information in an hour, minute and second format indicating the current time;
A first counter management unit for increasing the first counter value at a predetermined time interval;
A transmission unit that transmits the time information and the first counter value at the same time as the synchronization time information and the synchronization counter value, respectively;
Each of the plurality of playback devices is
A content acquisition unit for acquiring content;
(I) acquiring the synchronization time information and the synchronization counter value transmitted by the transmission unit; (ii) acquiring target time information in an hour / minute / second format indicating a time at which the content is to be reproduced;
A second counter management unit configured to increase a second counter value at the predetermined time interval, wherein the second counter management unit sets the synchronous counter value to the second counter value;
A target counter value is calculated by adding a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value;
(A) When the second counter value is smaller than the calculated target counter value, when the second counter value matches the calculated target counter value, control is performed to reproduce the content from the beginning.
(B) When the second counter value is not smaller than the calculated target counter value, an increase amount from the target counter value to the second counter value is calculated, and a time corresponding to the calculated increase amount A playback control unit that controls playback of the content from a position advanced from the beginning of the content,
The acquisition unit further includes:
The synchronization time information to be acquired and the specific information for specifying the synchronization device that is the transmission source of the synchronization counter value are held, and the specific information is changed to the specific information of another synchronization device different from the synchronization device The synchronization time information and the synchronization counter value transmitted by the transmission unit of the other synchronization device,
The reproduction system performs a control for reproducing the content by newly calculating an increase amount using the synchronization time information and the synchronization counter value acquired from the other synchronization device. A playback system comprising a synchronization device and a plurality of playback devices,
The synchronization device includes:
A time management unit for managing time information in an hour, minute and second format indicating the current time;
A first counter management unit for increasing the first counter value at a predetermined time interval;
A transmission unit that transmits the time information and the first counter value at the same time as the synchronization time information and the synchronization counter value, respectively;
Each of the plurality of playback devices is
A content acquisition unit for acquiring content;
(I) acquiring the synchronization time information and the synchronization counter value transmitted by the transmission unit; (ii) acquiring target time information in an hour / minute / second format indicating a time at which the content is to be reproduced;
A second counter management unit configured to increase a second counter value at the predetermined time interval, wherein the second counter management unit sets the synchronous counter value to the second counter value;
A target counter value is calculated by adding a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value;
(A) When the second counter value is smaller than the calculated target counter value, when the second counter value matches the calculated target counter value, control is performed to reproduce the content from the beginning.
(B) When the second counter value is not smaller than the calculated target counter value, an increase amount from the target counter value to the second counter value is calculated, and a time corresponding to the calculated increase amount A playback control unit that controls playback of the content from a position advanced from the beginning of the content,
The content acquisition unit acquires a plurality of content files and a playlist indicating a reproduction order of the plurality of content files as the content,
The reproduction control unit
Playing back the content by playing the plurality of content files in the playback order,
If the second counter value is not smaller than the calculated target counter value, it corresponds to a position advanced from the start of reproduction in the reproduction order by the time corresponding to the calculated increase amount in the control. , Specifying a content file and a position in the content file, playing the specified content file from the specified position,
The acquisition unit acquires the second playlist after acquiring the first playlist that is the playlist,
In the case where the second playlist is different from the first playlist, the playback control unit, in the control, in the playback order shown in the second playlist for the time corresponding to the calculated increase amount. The content file shown in the second playlist and the position in the content file corresponding to the position advanced from the start of reproduction are identified, and the identified content file is reproduced from the identified position
Playback system. A playback method in a playback system comprising a synchronization device and a plurality of playback devices,
A time management step in which the synchronization device manages time information in an hour / minute / second format indicating the current time;
A first counter management step in which the synchronization device increases a first counter value at predetermined time intervals;
The synchronization device includes a transmission step of transmitting the time information and the first counter value at the same time as the synchronization time information and the synchronization counter value, respectively.
A content acquisition step in which each of the plurality of playback devices acquires content;
Each of the plurality of playback devices acquires (i) the synchronization time information and the synchronization counter value transmitted in the transmission step, and (ii) a target time in an hour, minute and second format indicating a time at which the content should be played back An acquisition step for acquiring information;
A second counter management step in which each of the plurality of playback devices increases a second counter value at the predetermined time interval, and the second counter management step sets the synchronous counter value to the second counter value; ,
Each of the plurality of playback devices calculates a target counter value by adding a difference counter value corresponding to a difference time determined by the target time information and the synchronization time information to the synchronization counter value,
(A) When the second counter value is smaller than the calculated target counter value, control is performed to reproduce the content when the second counter value matches the calculated target counter value.
(B) When the second counter value is not smaller than the calculated target counter value, an increase amount from the target counter value to the second counter value is calculated, and a time corresponding to the calculated increase amount minute only carry out the control for reproducing the content from the advanced position from the beginning of the content, look including a reproduction control step
In the playback control step, the content is repeatedly played back,
In the case where the second counter value is not smaller than the calculated target counter value, in the control, in the content corresponding to the position advanced from the start of the repeated reproduction by the time corresponding to the calculated increase amount A reproduction method for identifying the position of the content and reproducing the content from the identified position .

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