JP2016103783A - Reproduction control device, reproduction control method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a frame in contents to be reproduced from being missed or overlapped.SOLUTION: A reproduction control device 10 comprises: a timer 304 for managing a present counter value that is a counter value to increase at an interval of a predetermined time; a memory 306 for output which holds each of a plurality of frames successively as a target frame; a synchronizing signal generation part which cyclically generates a vertical synchronizing signal and outputs the generated vertical synchronizing signal to a reproduction device 20; a signal output part 303 which outputs the target frame being held in the memory 306 for output to the reproduction device 20 synchronously with the vertical synchronizing signal; and a control part 301 which calculates a differential value between a reproduction counter value added to the target frame and the present counter value at the time when the signal output part 303 outputs the target frame, and performs control for increasing/decreasing the cycle of the vertical synchronizing signal on the basis of the calculated differential value in such a manner that a differential value that is calculated for a subsequent frame after the target frame among the plurality of frames is settled within a predetermined proper range.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a playback control device, a playback control method, and a program.

  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 received via a network or stored in a storage device in the playback device.

  Timing information for indicating the playback timing in the playback device is added to the image to be played back, and the playback device plays back the content based on the added timing information.

  Patent Document 1 discloses a technique for synchronizing reproduction timing between a transmission device (master device) that transmits content and a reproduction device (child device) that receives and reproduces content.

Japanese Patent No. 5418033

  However, there may be a difference between the advance speed of the time information managed by the apparatus to which the timing information is added and the advance speed of the time information managed by the playback apparatus. When the difference occurs, there is a problem that a missing or overlapping frame occurs while the content is played back by the playback device, and the viewing effect is lowered.

  The present invention has been made to solve the above problem, and an object of the present invention is to provide a playback control device and the like that suppress the occurrence of missing or overlapping frames in the content to be played back.

  In order to solve the above problem, a playback control device according to an aspect of the present invention is a playback control device for causing a playback device to play back content including a plurality of frames, and each of the plurality of frames includes: A reproduction counter value that is a counter value indicating the timing at which the frame should be reproduced is added, and the reproduction control device includes a timer that manages a current counter value that is a counter value that increases every predetermined time; An output memory that sequentially holds each of the frames as a target frame, a synchronization signal generation unit that periodically generates a vertical synchronization signal and outputs the generated vertical synchronization signal to the playback device, and the vertical synchronization A signal output unit for outputting the target frame held in the output memory to the playback device in synchronization with a signal; and the target frame A difference value between the added reproduction counter value and the current counter value when the signal output unit outputs the target frame is calculated, and the target among the plurality of frames is calculated based on the calculated difference value. A control unit that performs control to increase or decrease the period of the vertical synchronization signal so that a difference value calculated for a subsequent frame after the frame falls within a predetermined appropriate range.

  According to this, the reproduction control device adjusts by increasing / decreasing the period of the vertical synchronization signal based on the update period of the reproduction counter value. The reproduction counter value added to the frame is managed by the device that generated the frame. Even if the device that generated the frame and the playback control device intend to advance the counter value at the same speed, there is a slight time difference between the two due to individual differences in hardware, and the time difference as time elapses. Accumulate. This time difference causes missing or overlapping frames to be reproduced in the reproduction apparatus. Therefore, by adjusting the period of the vertical synchronization signal based on the update period of the reproduction counter value, it is controlled to reduce the time difference, and by outputting the frame to the reproduction device at the timing according to the adjusted vertical synchronization signal, Missing or overlapping frames to be reproduced can be avoided. Therefore, the playback control device can suppress the occurrence of missing or overlapping frames in the content to be played back.

  Further, the control unit calculates, as the difference value, a value obtained by subtracting the current counter value when the signal output unit outputs the target frame from the reproduction counter value, and (i) the difference value is a positive value. When the difference value is negative, the period of the vertical synchronization signal is increased. (Ii) When the difference value is negative, the period of the vertical synchronization signal is decreased.

  According to this, the reproduction control device specifically calculates the difference value, and increases or decreases the period of the vertical synchronization signal based on the sign of the difference value. Therefore, the playback control apparatus can more appropriately suppress the occurrence of frame loss or duplication in the content to be played back.

  The control unit calculates a plurality of the difference values, calculates a statistical difference value by statistically processing the calculated plurality of difference values, and uses the calculated statistical difference value as the difference value. Increase or decrease the period of the vertical sync signal.

  According to this, the reproduction control apparatus adjusts the vertical synchronization signal using the difference value calculated based on the reproduced plurality of frames after reproducing the plurality of frames. By adjusting using a plurality of frames, the playback control device suppresses the influence of the counter value delay or packet delay that occurs suddenly, and considers the trend of the update cycle of the playback counter value over a relatively long period of time. The vertical synchronization signal can be adjusted.

  Also, the period of the vertical synchronization signal is increased or decreased only when the difference value is out of the predetermined appropriate range.

  According to this, the reproduction control apparatus adjusts the period of the vertical synchronization signal only when the difference between the period in which the reproduction counter value is added and the vertical synchronization signal is relatively large. By adjusting the period of the vertical synchronization signal to the minimum necessary, a stable vertical synchronization signal and frame can be output to the display device, and the processing load can be reduced.

  Further, the playback control device is communicably connected via a network to a transmission device holding the content, and the control unit acquires the target frame from the transmission device via the network, The acquired target frame is stored in the output memory.

  According to this, the playback control device determines the vertical synchronization signal of its own device based on the difference between the playback counter value added to the frames transmitted via the network and sequentially stored in the output memory and the current counter value of its own device. Adjust the period. Thereby, it is possible to reproduce a plurality of frames transmitted from the transmission device while suppressing occurrence of omission or duplication.

  Further, the control unit further increases or decreases the predetermined time so that the current counter value when the frame is acquired falls within an appropriate delay range determined from the reproduction counter value added to the target frame. The timer is controlled so that

  According to this, the reproduction control device controls the current counter value updated in the reproduction control device to be updated while maintaining an appropriate amount of delay with respect to the reproduction counter value updated in the transmission device. Thereby, it is possible to reproduce a plurality of frames transmitted from the transmission device while maintaining an appropriate time difference and suppressing occurrence of omission or duplication.

  The reproduction control device further includes a storage that holds the content, and the control unit acquires the target frame from the storage, and stores the acquired target frame in the output memory.

  According to this, when playing back a plurality of frames held by the storage, the playback control device automatically uses the counter value update cycle used by the device that generated and recorded the plurality of frames. Adjust the period of the vertical sync signal of the device. Thereby, it is possible to reproduce a plurality of frames held by the storage while suppressing the occurrence of missing or overlapping frames.

  Each of the plurality of frames is a telop portion located at a common position in each of the plurality of frames, and a character that moves at a constant speed in a predetermined direction in the telop portion when the content is reproduced. It has a telop part to contain.

  According to this, when there is a missing or overlapping frame, the playback control device detects the occurrence of a missing or overlapping frame when playing back a content including a telop that is easily recognized by the viewer. Can be suppressed. Thereby, the viewing effect of the viewer can be improved.

  In addition, the reproduction control device further includes a buffer that holds a predetermined number of frames of the plurality of frames, and the control unit includes the buffer of the predetermined number of frames held in the buffer. By storing in the output memory one frame that is included in the predetermined memory storage permission range determined from the reproduction counter value of the one frame in the output memory, the output memory The target frame is held in a memory.

  According to this, the reproduction control apparatus can temporarily hold a frame to be stored in the output memory. By sequentially storing the frames from the buffer in the output memory, the frames can be output stably.

  A playback control method according to an aspect of the present invention is a playback control method in a playback control apparatus for causing a playback apparatus to play back content including a plurality of frames, and each of the plurality of frames includes a corresponding frame. A reproduction counter value, which is a counter value indicating the timing at which the video is to be reproduced, is added, and the reproduction control device includes a timer that manages a current counter value that is a counter value that increases every predetermined time, and the plurality of frames And an output memory for sequentially holding each of them as a target frame, wherein the reproduction control method periodically generates a vertical synchronization signal and outputs the generated vertical synchronization signal to the reproduction device. And outputting the target frame held in the output memory to the playback device in synchronization with the vertical synchronization signal. A difference value between the signal output step, the reproduction counter value added to the target frame, and the current counter value when the target frame is output in the signal output step is calculated, and based on the calculated difference value And a control step of performing control to increase / decrease the period of the vertical synchronization signal so that a difference value calculated for a subsequent frame after the target frame among the plurality of frames falls within a predetermined appropriate range.

  According to this, the same effect as the above-mentioned reproduction control device is produced.

  A program according to one embodiment of the present invention is a program for causing a computer to execute the above-described reproduction control method.

  According to this, the same effect as the above-mentioned reproduction control device is produced.

  The playback control apparatus according to the present invention can suppress the occurrence of missing or overlapping frames in the content to be played back.

FIG. 1 is a block diagram showing the configuration of the reproduction control system according to the first embodiment. FIG. 2 is a block diagram illustrating a hardware configuration of the reproduction control apparatus according to the first embodiment. FIG. 3 is a block diagram showing a detailed configuration of the reproduction processing unit according to the first embodiment. FIG. 4 is a flowchart showing processing at the time of frame acquisition of the reproduction processing unit according to the first embodiment. FIG. 5 is a flowchart showing a frame storing process in the output memory according to the first embodiment. FIG. 6 is a flowchart showing signal output processing to the playback apparatus according to the first embodiment. FIG. 7 is a flowchart showing processing for increasing / decreasing the period of the vertical synchronization signal according to the first embodiment. FIG. 8 is a timing diagram showing the output timing of the output frame when the period of the vertical synchronization signal according to the first embodiment is increased. FIG. 9 is a timing chart showing the output timing of the output frame when the period of the vertical synchronization signal according to the first embodiment is decreased. FIG. 10 is an explanatory diagram showing reproduction counter values of a plurality of frames according to the first embodiment. FIG. 11 is a timing diagram showing the frame output timing when there is no omission or duplication in the output frame, related to the first embodiment. FIG. 12 is a first timing diagram showing frame output timing according to the first embodiment. FIG. 13 is a second timing chart showing the frame output timing according to the first embodiment. FIG. 14 is a block diagram showing a configuration of the reproduction control system according to the second embodiment. FIG. 15 is a timing diagram showing frame output timing when there is no omission or duplication in the output frame, which is related to the second embodiment. FIG. 16 is a first timing diagram illustrating frame output timing according to the second embodiment. FIG. 17 is a second timing diagram illustrating the frame output timing according to the second embodiment. FIG. 18 is an explanatory diagram of a specific example of content in each 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 description will be given of a playback control device and the like that can suppress the occurrence of frame loss or duplication in content to be played back when content received via a network is played back. In the following description, the operation of the regeneration control device in the present embodiment is compared with the operation of the regeneration control device in the related art.

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

  As shown in FIG. 1, the reproduction control system 1 includes a reproduction control device 10, a reproduction device 20, and a transmission device 30. Further, the playback control device 10 and the playback device 20 are connected by a signal line 40. Further, the transmission device 30 and the reproduction control device 10 are connected via a network 50 so that they can communicate with each other.

  The transmission device 30 is a transmission device that transmits content to be reproduced by the reproduction device 20 to the reproduction control device 10 through the network 50. The content includes a plurality of frames. The transmission device 30 adds a counter value indicating the timing at which the frame is to be reproduced to each frame constituting the content, and transmits the frame to which the counter value is added to the reproduction control device 10.

  Specifically, the transmission device 30 includes a timer that adds a counter value at regular intervals. The transmission device 30 generates a plurality of frames constituting the content, and adds a counter value indicating the generated timing to each of the generated frames. This counter value corresponds to the timing to be played back by the playback device 20.

  The fixed time is, for example, (1/90000) seconds (90 kHz when expressed as a frequency). Note that the time may not exactly match due to individual differences in hardware. The content frame rate is, for example, 30 fps. Therefore, a counter value every about 3000 is added to each successive frame. In the following description, the case where these numerical values are used will be described. However, the present invention is not limited to these numerical values, and the same description can be applied to other numerical values.

  The playback control device 10 is a playback control device that controls playback of content. The playback control device 10 acquires content by receiving the content from the transmission device 30 via the network 50. Further, the playback control device 10 outputs a signal for playing back the content by the playback device 20 to the playback device 20 through the signal line 40 based on the counter value added to each frame constituting the acquired content. The signal line 40 is a communication line that conforms to, for example, the HDMI (registered trademark) (High-Definition Multimedia Interface) standard.

  The playback device 20 is a playback device that plays back content by displaying it on a display screen. The playback device 20 receives a signal for playing back content from the playback control device 10 through the signal line 40, and plays back the content according to the received signal.

  Note that the playback control device 10 may further include the function of the playback device 20. Conversely, the playback device 20 may further include the function of the playback control device 10.

  FIG. 2 is a block diagram showing a hardware configuration of the playback control apparatus 10 according to the present embodiment.

  As shown in FIG. 2, the playback control apparatus 10 includes a CPU 101 (Central Processing Unit), a main memory 102, a storage 103, a network interface 104 (Network Interface) 104, and a playback processing unit 105.

  The CPU 101 is a processor that executes a control program stored in a storage or the like.

  The main memory 102 is a volatile storage area used as a work area used when the CPU 101 executes a control program.

  The storage 103 is a non-volatile storage area that holds a control program, content, and the like.

  The NIF 104 is a network interface that transmits data to other devices via the network or receives data from other devices.

  The reproduction processing unit 105 is a processing unit that receives content through the NIF 104 and transmits a signal for reproducing the received content to the reproduction device 20. The operation of the reproduction processing unit 105 will be described in detail later.

  FIG. 3 is a block diagram showing a detailed configuration of the reproduction processing unit 105 according to the present embodiment.

  As illustrated in FIG. 3, the reproduction processing unit 105 includes a control unit 301, a synchronization signal generation unit 302, a signal output unit 303, a timer 304, a buffer 305, and an output memory 306.

  The synchronization signal generation unit 302 generates a vertical synchronization signal to be output to the playback device 20. The synchronization signal generation unit 302 generates a vertical synchronization signal based on a clock signal having a predetermined period (for example, 60 Hz). The period of the clock signal is engraved by dividing the original clock signal of about several MHz that is the source of the clock signal. The frequency division ratio can be controlled by the control unit 301, and the period of the vertical synchronization signal is increased or decreased by increasing or decreasing the frequency division ratio. The range of increase / decrease in the period of the vertical synchronization signal needs to be included in the range allowed by the playback device 20 as the vertical synchronization signal. The range of increase / decrease can be, for example, ± 0.5% with respect to the set value.

  The signal output unit 303 is a processing unit that outputs a vertical synchronization signal and a signal indicating an image (hereinafter also referred to as an image signal) to the playback device 20. The signal output unit 303 outputs the vertical synchronization signal generated by the synchronization signal generation unit 302 to the playback device 20. The signal output unit 303 reads a frame stored in the output memory 306, generates an image signal indicating the frame, and outputs the generated image signal to the playback device 20 in synchronization with the vertical synchronization signal. . Note that outputting an image signal indicating a frame is also simply expressed as “outputting a frame”.

  The timer 304 is a processing unit that manages a counter value indicating the processing timing of each function in the reproduction processing unit 105. The timer 304 is updated by incrementing the counter value by 1 every predetermined time. The predetermined time is, for example, (1/90000) seconds (90 kHz in terms of frequency). The predetermined time is engraved by dividing the original clock signal of about several MHz that is the source. The frequency division ratio can be controlled by the control unit 301, and the time interval at which the counter value is added is increased or decreased by increasing or decreasing the frequency division ratio. As a result, the update cycle varies, for example, as 89.5 kHz or 90.5 kHz.

  In addition, the counter value of the timer 304 can be set (overwritten) by the control unit 301.

  Note that the time may be different for each hardware due to individual differences in hardware. Note that the count value managed by the timer 304 may be referred to as the current count value. In addition, the addition of the count value may be expressed as “the count value advances”, and the cycle in which the count value is added may be expressed as the “addition cycle”.

  The buffer 305 is a storage device that receives a frame constituting the content through the NIF 104 and temporarily stores the received frame. The buffer 305 has a capacity capable of storing a plurality of frames. For example, the buffer 305 can store four frames. The frame stored in the buffer 305 is stored in the output memory 306 by the control unit 301 at an appropriate timing. The buffer 305 is realized by a data structure such as a ring buffer or a queue.

  The output memory 306 is a storage device that sequentially and temporarily stores output frames among a plurality of frames included in the content. The output memory 306 has a capacity capable of storing one frame. Frames are stored in the output memory 306 by the control unit 301. The frame stored in the output memory 306 is read by the signal output unit 303 at an appropriate timing.

  The control unit 301 is a processing unit that controls each function in the reproduction processing unit 105. Specifically, the control unit 301 stores each frame stored in the buffer 305 in the output memory 306 at an appropriate timing based on the current counter value.

  In addition, the control unit 301 calculates the difference between the counter value held by the transmission device 30 and the current counter value, and increases or decreases the frequency division ratio of the timer 304 based on the calculated difference, whereby the counter value of the transmission device 30 is obtained. Control is performed so that the current counter value advances while maintaining a more appropriate amount of delay. The control unit 301 can also set an appropriate value for the counter value of the timer 304 when the difference is relatively large during the control.

  Further, the control unit 301 calculates a difference value between the reproduction counter value of the frame corresponding to the image signal output from the signal output unit 303 and the current counter value when the signal output unit 303 outputs the image signal. Based on the obtained difference value, control is performed to increase / decrease the period of the vertical synchronization signal so that the difference value calculated for the subsequent frame after the frame among the plurality of frames falls within a predetermined appropriate range. Thus, the control unit 301 controls the synchronization signal generation unit 302 to increase or decrease the period of the vertical synchronization signal so that the period of the vertical synchronization signal approaches the time corresponding to the change width of the reproduction counter value for one frame. Do it. Details will be described later.

  Hereinafter, the operation of each functional block will be described in more detail using flowcharts.

  FIG. 4 is a flowchart showing processing at the time of frame acquisition of the reproduction processing unit 105 according to the present embodiment.

  In step S <b> 101, the network interface 104 acquires the frame that constitutes the content from the transmission device 30 via the network. A reproduction counter value, which is a counter value indicating the timing at which this frame should be reproduced, is added to the acquired frame.

  In step S102, the frame received in step S101 is stored in the buffer 305. If the frame transmitted in step S101 has been encoded (encoded), the frame is decoded (decoded) and stored in the buffer 305.

  In step S <b> 103, the control unit 301 acquires the current counter value from the timer 304.

  In step S104, the control unit 301 determines that the current counter value acquired in step S103 is within an appropriate delay range determined from the reproduction counter value in the frame received in step S101, is smaller than the lower limit of the range, or It is determined whether it is larger than the upper limit of the range. Here, the appropriate delay range is a range from the reproduction counter value to a counter value that is decreased from the reproduction counter value by a predetermined value. The appropriate delay range is to advance the current counter value while maintaining an appropriate delay from the counter value of the transmission device 30. Specifically, for example, the appropriate delay range is a range from a counter value obtained by subtracting 2000 from the reproduction counter value to a counter value obtained by subtracting 500 from the reproduction counter value.

  If it is determined in step S104 that the current counter value is within the appropriate delay range, the series of processes shown in FIG. 4 is terminated. If the current counter value is smaller than the lower limit of the appropriate delay range, the process proceeds to step S111. If the current counter value is larger than the upper limit of the appropriate delay range, the process proceeds to step S121.

  In step S111, the control unit 301 shortens the addition period of the counter value of the timer 304, that is, causes the counter value to advance faster. Specifically, the control unit 301 shortens the counter value addition cycle by reducing the frequency division ratio of the timer 304. If the current counter value is smaller than the lower limit of the appropriate delay range and the difference between them is relatively large, set the current counter value within the appropriate delay range by setting the current counter value within the appropriate delay range. You may make it contain.

  In step S121, the control unit 301 increases the counter value addition cycle of the timer 304, that is, causes the counter value to proceed slowly. Specifically, the control unit 301 increases the counter value addition cycle by increasing the frequency division ratio of the timer 304. If the current counter value is larger than the upper limit of the appropriate delay range and the difference between them is relatively large, set the current counter value within the appropriate delay range by setting the current counter value to a value within the appropriate delay range. You may make it contain.

  By the series of processes shown in FIG. 4, the frames constituting the content are stored in the buffer 305, and the current counter value managed by the reproduction processing unit 105 is delayed from the counter value in the transmission device 30 by the difference counter value. Can proceed. In addition, the process after step S103 among the processes shown in FIG. 4 may not be performed every time a packet is received, may be performed every time a plurality of packets are received, or every predetermined time. It may be performed when a packet is received.

  FIG. 5 is a flowchart showing a frame storing process in the output memory according to the present embodiment.

  The process shown in FIG. 5 is performed for each frame held by the buffer 305 and is repeated. In the following description, among the frames held by the buffer 305, a frame to be processed is referred to as a target frame.

  In step S <b> 201, the control unit 301 acquires the current counter value from the timer 304.

  In step S202, the control unit 301 acquires a reproduction counter value of the target frame.

  In step S203, the control unit 301 determines that the current counter value acquired in step S203 is within the memory storage permission range determined from the reproduction counter value of the target frame, is smaller than the lower limit of the range, or is the upper limit of the range. Determine if greater than. Here, the memory storage permission range is a range of a predetermined counter value whose upper limit is the reproduction counter value. For example, the width of the predetermined counter value is 2000. In this case, if the reproduction counter value of the frame is 3000, the range of the counter value from 1000 to 3000 is the memory storage permission range.

  If it is determined in step S203 that the current counter value is within the memory storage permission range, the process proceeds to step S204. If the current counter value is smaller than the lower limit of the memory storage permission range, the series of processing shown in FIG. 5 is terminated and the timing for outputting a frame is awaited. If the current counter value is larger than the upper limit of the memory storage permission range, the process proceeds to step S221.

  In step S <b> 204, the control unit 301 stores the target frame in the output memory 306. The target frame stored in the output memory 306 is output to the playback device 20 by subsequent processing.

  In step S205, the control unit 301 performs control to increase or decrease the period of the vertical synchronization signal so that the period of the vertical synchronization signal approaches the time when the counter value advances by the increment of the counter value corresponding to one frame. This is performed on the generation unit 302. Details will be described later.

  In step S221, the control unit 301 discards the target frame. This is because when the current counter value is larger than the upper limit of the memory storage permission range, the timing for reproducing the target frame has already passed, and the target frame will not be reproduced in the future.

  By the series of processes shown in FIG. 5, the frame stored in the buffer 305 is stored in the output memory 306 at an appropriate timing, and the period of the vertical synchronization signal generated by the synchronization signal generation unit 302 is set appropriately. can do.

  FIG. 6 is a flowchart showing a signal output process to the playback apparatus according to the present embodiment.

  Note that the processing from step S301 to step S303 is repeatedly executed.

  In step S301, the signal output unit 303 monitors the signal generated by the synchronization signal generation unit 302 in order to detect the vertical synchronization signal generated by the synchronization signal generation unit 302.

  If the signal output unit 303 detects a vertical synchronization signal in step S301 (Yes in step S301), the process proceeds to step S302. On the other hand, when the vertical synchronization signal is not detected (No in step S301), step S301 is executed again. That is, the signal output unit 303 stands by in step S301 until a vertical synchronization signal is detected.

  In step S <b> 302, the signal output unit 303 outputs the vertical synchronization signal generated by the synchronization signal generation unit 302 to the playback device 20.

  In step S <b> 303, the signal output unit 303 generates an image signal indicating the frame held in the output memory 306, and outputs the generated image signal to the playback device 20. At this time, the signal output unit 303 outputs an image signal in synchronization with the vertical synchronization signal output in step S302.

  With the series of processing shown in FIG. 6, the frame held in the output memory 306 together with the vertical synchronization signal can be output to the playback device 20 in synchronization with the vertical synchronization signal. Since frames are sequentially stored in the output memory 306 by the processing shown in FIG. 5, the stored frames are sequentially output to the playback device 20 by the processing shown in FIG. To play the video.

  FIG. 7 is a flowchart showing processing for increasing / decreasing the period of the vertical synchronization signal according to the present embodiment. The process shown in FIG. 7 shows the process of step S205 in FIG. 5 in detail.

  In step S401, the control unit 301 calculates a difference counter value that is a difference between the reproduction counter value in the target frame and the current counter value when the signal output unit 303 outputs the image signal indicating the target frame. Specifically, the difference counter value is calculated by (Equation 1).

  Difference counter value = Playback counter value-Current counter value when image signal is output (Formula 1)

  In addition, the control unit 301 calculates a plurality of difference counter values by performing the above-described calculation of the difference counter value for a plurality of target frames. For example, the control unit 301 calculates difference counter values for four frames (also referred to as past four frames) including the target frame and the three frames before the target frame.

  In step S402, the control unit 301 calculates an average value of difference counter values for the past four frames calculated in step S401. Instead of calculating the average value, an appropriate statistical process, for example, a process for obtaining a median value or a mode value may be performed. Note that step S402 is not essential, and the following processing can be performed using the difference counter value of any one of the past four frames. In the following processing, the difference counter value or the average value of the difference counter values is also referred to as “difference value”.

  In step S403, the control unit 301 determines whether the average value calculated in step S402 is within a predetermined appropriate range, smaller than the lower limit of the range, or larger than the upper limit of the range. Here, the appropriate range is a range for adjusting the difference between the timing at which the target frame is stored in the output memory 306 and the timing at which the target frame is output by the signal output unit 303. To 800.

  If it is determined in step S403 that the average value is within the appropriate range, the series of processes shown in FIG. If the average value is smaller than the lower limit of the appropriate range, the process proceeds to step S411. When the average value is larger than the upper limit of the appropriate range, the process proceeds to step S421.

  In step S411, the control unit 301 controls the frequency division ratio of the synchronization signal generation unit 302 to reduce the period of the vertical synchronization signal. Step S411 corresponds to a case where the average value is negative.

  In step S421, the control unit 301 controls the frequency division ratio of the synchronization signal generation unit 302 to increase the period of the vertical synchronization signal. Step S421 corresponds to a case where the average value is positive.

  Through a series of processes shown in FIG. 7, the control unit 301 increases or decreases the period of the vertical synchronization signal so that the period of the vertical synchronization signal approaches the time corresponding to the change width of the reproduction counter value for one frame. As a result, control is performed so that the difference value calculated for the subsequent frame after the target frame falls within the appropriate range.

  Hereinafter, the effect of controlling the period of the vertical synchronization signal by the control unit 301 will be described.

  FIG. 8 is a timing chart showing the output timing of the output frame when the period of the vertical synchronization signal according to the present embodiment is increased.

  In FIG. 8, the horizontal axis indicates the time, the counter value of the timer 304, the frame stored in the output memory 306, the vertical synchronization signal generated by the synchronization signal generation unit 302, and the frame output by the signal output unit 303. Each is shown against time. In addition, frames A, B, K, and L are shown as frames constituting the content. Reproduction counter values of frames A, B, K, and L are 3000, 6000, 33000, and 36000, respectively. FIGS. 8A and 8B show counter values before and after increasing the period of the vertical synchronization signal, respectively. The width of the memory storage permission range is 2000. The appropriate range is a range from 0 to 800.

  In FIG. 8A, the period of the vertical synchronization signal is T1. The control unit 301 stores the frame A in the output memory 306 when the current counter value is 1000 (step S102). The signal output unit 303 detects the vertical synchronization signal when the current counter value is 2000, and outputs the frame A (steps S301 and S302). In this case, the difference counter value Δt (A) for the frame A is calculated as Δt (A) = 3000−2000 = 1000 by (Equation 1) (step S401).

  The difference counter value Δt (B) for the frame B is calculated as Δt (B) = 6000−5000 = 1000 as described above. It is assumed that such a difference counter value is similarly calculated for other frames, and the average value of the difference counter values calculated from a plurality of frames including frames A and B is 1000 (step S402).

  The control unit 301 determines that the average value is larger than the upper limit of the appropriate range (step S403), and increases the period of the vertical synchronization signal to T2 shown in FIG. 8B (step S421). Since the output timing of the frame is earlier than the setting, the output timing of the frame is brought closer to the setting by delaying the vertical synchronization signal.

  Processing for frames K and L, which are subsequent frames after frames A and B, will be described with reference to FIG.

  In FIG. 8B, the differential counter value Δt (K) for the frame K is Δt (K) = 33000−32100 = 900 according to (Equation 1).

  The difference counter value Δt (L) for the frame L is Δt (L) = 36000−35200 = 800 as described above. Compared to the case of frames A and B, the difference counter value is decreased and is within an appropriate range.

  In this way, the control unit 301 can control the timing for outputting the subsequent frame to be close to the timing for reproducing the frame by increasing the period of the vertical synchronization signal.

  FIG. 9 is a timing chart showing the output timing of the output frame when the period of the vertical synchronization signal according to the present embodiment is decreased. The items shown in FIG. 9, the reproduction counter value of each frame, the width of the memory storage permission range, the appropriate range, and the like are the same as those shown in FIG.

  In FIG. 9A, the period of the vertical synchronizing signal is T3. The control unit 301 stores the frame A in the output memory 306 when the current counter value is 2000 (step S102). The signal output unit 303 detects the vertical synchronization signal when the current counter value is 3200, and outputs the frame A (steps S301 and S302). In this case, the difference counter value Δt (A) for the frame A is calculated as Δt (A) = 3000−3200 = −200 by (Equation 1) (step S401).

  The difference counter value Δt (B) for the frame B is calculated as Δt (B) = 6000−6200 = −200, as described above. It is assumed that such a difference counter value is similarly calculated for other frames, and the average value of the difference counter values calculated from a plurality of frames including frames A and B is −200 (step S402).

  The control unit 301 determines that the average value is smaller than the lower limit of the appropriate range (step S403), and reduces the period of the vertical synchronization signal to T4 shown in FIG. 9B (step S411). Since the output timing of the frame is delayed from the setting, the output timing of the frame is brought closer to the setting by advancing the vertical synchronization signal.

  Processing for frames K and L, which are subsequent frames after frames A and B, will be described with reference to FIG.

  In FIG. 9B, the difference counter value Δt (K) for the frame K is Δt (K) = 33000−33100 = −100 according to (Equation 1).

  The difference counter value Δt (L) for the frame L is Δt (L) = 36000−36000 = 0 as described above. Compared to the case of frames A and B, the difference counter value is increased and is within an appropriate range.

  In this way, the control unit 301 can control the timing for outputting the subsequent frame to be close to the timing for reproducing the frame by reducing the period of the vertical synchronization signal.

  Hereinafter, a series of processes in which the transmission device 30 transmits a plurality of frames constituting the content and the reproduction control device 10 outputs the plurality of frames to the reproduction device 20 at appropriate timing will be described in comparison with related technologies. To do. Here, the related technique is a technique in which the process of increasing / decreasing the vertical synchronization signal (step S205 in FIG. 5 and FIG. 7) is not performed.

  FIG. 10 is an explanatory diagram showing reproduction counter values of a plurality of frames according to the present embodiment.

  As shown in FIG. 10, the reproduction counter values of frames A, B, C, D, and E are 3000, 6000, 9000, 12000, and 15000, respectively. In other words, these reproduction counter values are added to each of the frames A and the like. The following description will be given using these frames.

  FIG. 11 is a timing chart showing the frame output timing when there is no omission or duplication in the output frame, related to the present embodiment.

  In FIG. 11, the horizontal axis indicates time, the counter value of the transmission device 30, the frame received by the NIF 104 and its timing, the counter value of the timer 304, the frame stored in the output memory 306, and the synchronization signal generator 302 Each of the generated vertical synchronization signal and the frame output by the signal output unit 303 is shown with respect to time. In addition, frames A, B, C, and D are shown as frames constituting the content. The width of the memory storage permission range is 2000.

  In the example illustrated in FIG. 11, when the counter value of the transmission device 30 is 3000, the transmission device 30 transmits the frame A. The NIF 104 of the playback control apparatus 10 receives the frame A, and the frame A is stored in the buffer 305 (steps S101 and S102). At this time, the counter value (current counter value) of the timer 304 is 2000.

  The control unit 301 stores the frame A in the output memory 306 (step S204) because the current counter value 2000 is within the range from 1000 to 3000 which is the memory storage permission range of the frame A (step S203). ). When a vertical synchronization signal is detected within a period in which frame A is stored in the output memory 306, the frame A is output in synchronization with the vertical synchronization signal. Thereafter, similarly, frames B, C, and D are output.

  In the example shown in FIG. 11, the time corresponding to 3000, which is the increment of the counter value corresponding to one frame, is equal to one cycle of the vertical synchronization signal corresponding to one frame, so that the frames are sequentially acquired. Are stored in the output memory 306 and output. In this case, the output frame is not lost or duplicated. That is, if the current counter value is added at the timing shown in FIG. 11 and the vertical synchronization signal is generated, all of the plurality of frames constituting the content are reproduced without duplication, which is an ideal state. .

  However, in reality, there is a difference (displacement) between the time the counter value advances by the increment of the counter value corresponding to one frame and one cycle of the vertical synchronization signal corresponding to one frame. A difference in the counter value addition period between the transmission device 30 and the timer 304 is generated, a counter value addition period is increased or decreased for the purpose of eliminating this difference, and a communication delay on the network 50 is performed. May occur. Due to these factors, the output frame is missing or overlapped. An example in which omission or duplication occurs in the output frame will be described below.

  FIG. 12 is a first timing diagram showing frame output timing according to the present embodiment. FIG. 12 also shows the frame output timing according to the related art. The items shown in FIG. 12 are the same as those shown in FIG. The related technique is a technique in which the process of increasing / decreasing the vertical synchronization signal (step S205 in FIG. 5 and FIG. 7) is not performed.

  In the example illustrated in FIG. 12, when the counter value of the transmission device 30 is 3000, the transmission device 30 transmits the frame A. The NIF 104 of the playback control apparatus 10 receives the frame A, and the frame A is stored in the buffer 305 (steps S101 and S102). At this time, the counter value (current counter value) of the timer 304 is 2500.

  The controller 301 stores the frame A in the output memory 306 (step S204) because the current counter value 2500 is within the memory storage permission range of the frame A (step S203).

  Next, when the counter value of the transmission device 30 is 6000, the transmission device 30 transmits the frame B, and the frame B is stored in the buffer 305 (steps S101 and S102). At this time, the counter value (current counter value) of the timer 304 is 5600.

  Here, at time X, it is determined that the current counter value 5600 is larger than the upper limit (5500) of the range from 4000 to 5500, which is the appropriate delay range of frame B (step S104), and the counter value of the timer 304 is added. The cycle is lengthened (step S121). As a result, the frame C is stored in the output memory 306 after a relatively long time has elapsed since the frame B was stored.

  In this situation, the timing and output frame of the vertical synchronization signal in the related art will be described with reference to FIG.

  In the related art, the vertical synchronization signal is uniformly generated at 60 Hz, and this period does not vary. Therefore, even if the current counter value addition cycle varies, the cycle of the vertical synchronization signal does not change.

  First, in a state where the frame A is stored in the output memory 306, the frame A is output in synchronization with the vertical synchronization signal. Frame B is output in the same manner. Next, since the addition period of the current counter value becomes longer, the vertical synchronization signal is detected in a state where the frame B that has already been output is stored in the output memory 306, and the frame B is output again (that is, Duplicate frame B is output). Furthermore, the output of the next frame C may be lost depending on the addition period of the current counter value.

  Next, the timing of the vertical synchronizing signal and the output frame in the reproduction control apparatus 10 according to the present embodiment will be described with reference to FIG.

  According to the reproduction control apparatus 10 in the present embodiment, the process of increasing / decreasing the period of the vertical synchronization signal based on the current counter value (step S205 in FIG. 5 and FIG. 7) is performed. Specifically, when the current counter value addition cycle becomes longer, control is performed so as to lengthen the cycle of the vertical synchronization signal. As a result, the output of frame B is not duplicated and the output of frame C is not lost, and all the frames are output once.

  FIG. 13 is a second timing chart showing the frame output timing according to the present embodiment. FIG. 13 also shows the frame output timing according to the related art. The items shown in FIG. 13 are the same as those shown in FIG.

  In the example illustrated in FIG. 13, when the counter value of the transmission device 30 is 3000, the transmission device 30 transmits the frame A. The NIF 104 of the playback control apparatus 10 receives the frame A, and the frame A is stored in the buffer 305 (steps S101 and S102). At this time, the counter value (current counter value) of the timer 304 is 500.

  Since the current counter value 500 is smaller than the lower limit of the frame A memory storage permission range (step S203), the control unit 301 does not perform any processing at this time. That is, the control unit 301 waits until the timing for outputting the frame A. When the current counter value reaches 1000 after a lapse of time, the current counter value falls within the memory storage permission range for frame A (step S203), so the control unit 301 stores frame A in the output memory 306. (Step S204).

  Next, when the counter value of the transmission device 30 is 6000, the transmission device 30 transmits the frame B, and the frame B is stored in the buffer 305 (steps S101 and S102). At this time, the counter value (current counter value) of the timer 304 is 3400.

  Here, at time X, it is determined that the current counter value 3400 is smaller than the lower limit (4000) of the range from 4000 to 5500, which is the appropriate delay range of frame B (step S104), and the counter value of the timer 304 is added. The cycle is shortened (step S111). As a result, the frame C is stored in the output memory 306 after a relatively short time has elapsed since the frame B was stored.

  In this situation, the timing and output frame of the vertical synchronization signal in the related art will be described with reference to FIG.

  In the related art, first, in a state where the frame A is stored in the output memory 306, the frame A is output in synchronization with the vertical synchronization signal. Next, when the current counter value addition cycle is short, the vertical synchronization signal is not detected in a state where the frame B is stored in the output memory 306, and the frame C is stored in the output memory 306. Then, in a state where the frame C is stored in the output memory 306, the vertical synchronization signal is detected, and the frame C is output. Similarly, frame D is output. In this way, the subsequent frames C and D are output without outputting the frame B (the frame B is missing).

  Next, the timing of the vertical synchronization signal and the output frame in the reproduction control apparatus 10 in the present embodiment will be described with reference to FIG.

  According to the reproduction control apparatus 10 in the present embodiment, when the current counter value addition period is shortened, control is performed so as to shorten the period of the vertical synchronization signal. As a result, the output of frame B is not lost, and all frames are output once.

  As described above, the reproduction control apparatus 10 according to the present embodiment adjusts by increasing / decreasing the period of the vertical synchronization signal based on the update period of the reproduction counter value. The reproduction counter value added to the frame is managed by the device that generated the frame. Even if each of the above devices and the reproduction control device is intended to be engraved in the same manner, a minute time difference occurs between the two due to individual differences in hardware, and the time difference accumulates as time passes. This time difference causes missing or overlapping frames to be reproduced in the reproduction apparatus. Therefore, by adjusting the period of the vertical synchronization signal based on the update period of the reproduction counter value and outputting the frame to the reproduction device at the timing according to the adjusted vertical synchronization signal, it is possible to avoid missing or overlapping frames to be reproduced Can do. Therefore, the playback control device can suppress the occurrence of missing or overlapping frames in the content to be played back.

  Further, the reproduction control device 10 specifically calculates the difference value, and increases or decreases the period of the vertical synchronization signal based on the sign of the difference value. Therefore, the playback control apparatus can more appropriately suppress the occurrence of frame loss or duplication in the content to be played back.

  In addition, after reproducing a plurality of frames, the reproduction control apparatus 10 adjusts the vertical synchronization signal using a difference value calculated based on the reproduced frames. By adjusting using a plurality of frames, the playback control device suppresses the influence of the counter value delay or packet loss that occurs suddenly, and considers the trend of the update counter value update period over a relatively long period of time. The vertical synchronization signal can be adjusted.

  Further, the reproduction control apparatus 10 adjusts the period of the vertical synchronization signal only when the difference between the period in which the reproduction counter value is added and the vertical synchronization signal is relatively large. By adjusting the period of the vertical synchronization signal to the minimum necessary, a stable vertical synchronization signal and image signal can be output to the display device, and the processing load can be reduced.

  Further, the playback control device 10 determines the period of the vertical synchronization signal of its own device based on the difference between the playback counter value added to the frames transmitted via the network and sequentially stored in the output memory and the current counter value of its own device. Make adjustments. Thereby, it is possible to reproduce a plurality of frames transmitted from the transmission device while suppressing occurrence of omission or duplication.

  Further, the playback control device 10 controls the current counter value updated in the playback control device to be updated while maintaining an appropriate amount of delay with respect to the playback counter value updated in the transmission device. Thereby, it is possible to reproduce a plurality of frames transmitted from the transmission device while maintaining an appropriate time difference and suppressing occurrence of omission or duplication.

  In addition, when there is a missing or overlapping frame, the playback control device 10 suppresses the occurrence of missing or overlapping frames when playing back a content including a telop that is easily recognized by the viewer. be able to. Thereby, the viewing effect of the viewer can be improved.

  Further, the playback control device 10 can temporarily hold a frame to be stored in the output memory. By sequentially storing the frames from the buffer in the output memory, the frames can be output stably.

(Embodiment 2)
In the present embodiment, a description will be given of a playback control device or the like that can suppress the occurrence of frame loss or duplication in content to be played back when content stored in a storage device is played back without going through a network. . In the following description, the operation of the regeneration control device in the present embodiment is compared with the operation of the regeneration control device in the related art.

  In addition, the same code | symbol is attached | subjected to the component same as the thing in Embodiment 1, and detailed description is abbreviate | omitted.

  FIG. 14 is a block diagram showing a configuration of the reproduction control system 2 according to the present embodiment.

  As shown in FIG. 14, the reproduction control system 2 includes a reproduction control device 12 and a reproduction device 20. Further, the playback control device 12 and the playback device 20 are connected by a signal line 40.

  The playback device 20 is the same as the playback device 20 in the first embodiment.

  The playback control device 12 has the same hardware configuration (FIG. 2) as the playback control device 10 in the first embodiment.

  The playback control device 12 is a playback control device that controls playback of content. The reproduction control device 12 outputs a signal for reproducing the content by the reproduction device 20 to the reproduction device 20 through the signal line 40 based on the counter value added to each frame constituting the content stored in the storage 103. To do.

  Processing at the time of frame acquisition by the playback control device 12 will be described. The processing at the time of frame acquisition by the playback control device 12 is different from that in the first embodiment (FIG. 4) only in the frame acquisition method. That is, in the playback control device 12, the playback processing unit 105 acquires the content stored in the storage 103 by reading the content in step S101. As with the first embodiment, a reproduction counter value, which is a counter value indicating the timing at which this frame should be reproduced, is added to the received frame.

  The frame storage processing in the output memory, the signal output processing to the playback device, and the processing for increasing / decreasing the period of the vertical synchronization signal by the playback control device 12 are the same as those in the first embodiment (FIGS. 5 and 5). 6 and FIG. 7).

  FIG. 15 is a timing chart showing the frame output timing when there is no omission or duplication in the output frame, related to the present embodiment.

  In FIG. 15, the horizontal axis indicates the time, the counter value of the timer 304, the frame stored in the output memory 306, the vertical synchronization signal generated by the synchronization signal generation unit 302, and the frame output by the signal output unit 303. Each is shown against time. In addition, frames A, B, C, and D are shown as frames constituting the content. The width of the memory storage permission range is 2000.

  The reproduction processing unit 105 reads the frame A from the storage 103 and stores it in the buffer 305 before the memory storage permission range of the frame A (steps S102 and S103). When the current counter value reaches 1000, the control unit 301 stores the frame A in the output memory 306 when it enters the memory storage permission range of the frame A (step S204).

  When a vertical synchronization signal is detected within a period in which frame A is stored in the output memory 306, the frame A is output in synchronization with the vertical synchronization signal. Thereafter, similarly, frames B, C, and D are output.

  In the example shown in FIG. 15, the time corresponding to 3000, which is the increment of the counter value corresponding to one frame, is equal to one cycle of the vertical synchronization signal corresponding to one frame, so that the first embodiment (FIG. 11) As in the case of), there is no omission or duplication in the output frame. That is, if the current counter value is added at the timing shown in FIG. 15 and the vertical synchronization signal is generated, all of the plurality of frames constituting the content are reproduced without duplication, which is an ideal state. .

  However, in reality, there may be a difference (displacement) between the time the counter value advances by the increment of the counter value corresponding to one frame and the vertical synchronization signal corresponding to one frame. In such a case, missing or overlapping occurs in the output frame. An example in which omission or duplication occurs in the output frame will be described below.

  FIG. 16 is a first timing diagram showing frame output timing according to the present embodiment. FIG. 16 also shows the frame output timing according to the related art. The items shown in FIG. 16 are the same as those shown in FIG.

  In the example shown in FIG. 16, a case will be described in which the period of the vertical synchronization signal corresponding to one frame is shorter than the time the counter value advances by the increment of the counter value corresponding to one frame.

  The reproduction processing unit 105 reads the frame A from the storage 103 and stores it in the buffer 305 before the memory storage permission range of the frame A (steps S102 and S103). When the current counter value reaches 1000, the control unit 301 stores the frame A in the output memory 306 when it enters the memory storage permission range of the frame A (step S204).

  Similarly, the frames B, C, and D are sequentially stored in the output memory 306 when the current counter values become 4000, 7000, and 10000, respectively (step S204).

  In this situation, the timing and output frame of the vertical synchronization signal in the related art will be described with reference to FIG. The related technique is a technique in which the process of increasing / decreasing the vertical synchronization signal (step S205 in FIG. 5 and FIG. 7) is not performed.

  In the related art, the vertical synchronization signal is uniformly generated at 60 Hz, and this period does not vary. Therefore, even if the current counter value addition cycle varies, the cycle of the vertical synchronization signal does not change.

  First, in a state where the frame A is stored in the output memory 306, the frame A is output in synchronization with the vertical synchronization signal. Frame B is output in the same manner. Next, since the cycle of the vertical synchronization signal is shorter than the width of the counter value corresponding to one frame, the vertical synchronization signal is detected in a state where the frame B that has already been output is stored in the output memory 306, and again Frame B is output (that is, output in duplicate).

  Next, the timing of the vertical synchronizing signal and the output frame in the reproduction control apparatus 12 in the present embodiment will be described with reference to FIG.

  According to the playback control device 12 in the present embodiment, the process of increasing / decreasing the period of the vertical synchronization signal based on the current counter value (step S205 in FIG. 5 and FIG. 7) is performed. Specifically, when the current counter value addition cycle is longer, control is performed so as to lengthen the cycle of the vertical synchronization signal. As a result, the output of frame B is not duplicated and all frames are output once.

  FIG. 17 is a second timing chart showing the frame output timing according to the present embodiment.

  FIG. 17 also shows the frame output timing according to the related art. The items shown in FIG. 17 are the same as those shown in FIG.

  In the example shown in FIG. 17, a case will be described in which the width of the vertical synchronization signal corresponding to one frame is longer than the width of the counter value corresponding to one frame.

  The reproduction processing unit 105 sequentially stores the frames A, B, C, D, and E in the output memory 306 as in the case of FIG.

  In this situation, the timing and output frame of the vertical synchronization signal in the related art will be described with reference to FIG.

  First, in a state where the frame A is stored in the output memory 306, the frame A is output in synchronization with the vertical synchronization signal. Frames B and C are output in the same manner. Next, since the period (fixed value) of the vertical synchronization signal is longer than the width of the counter value corresponding to one frame, the frame E is originally stored when the next frame D is stored in the output memory 306. In this state, a vertical synchronization signal is detected and frame E is output (that is, frame D is lost).

  Next, the timing of the vertical synchronizing signal and the output frame in the reproduction control apparatus 12 in the present embodiment will be described with reference to FIG.

  According to the playback control device 12 in the present embodiment, the process of increasing / decreasing the period of the vertical synchronization signal based on the current counter value (step S205 in FIG. 5 and FIG. 7) is performed. Specifically, when the current counter value addition cycle is longer, control is performed so as to shorten the cycle of the vertical synchronization signal. As a result, the frame D is output without being lost, and all the frames are output once.

  FIG. 18 is an explanatory diagram of a specific example (content 1800) of content in each embodiment.

  FIG. 18 shows three frames 1801, 1802, and 1803 among a plurality of frames constituting the content 1800. The content progresses in order from the left frame to the right frame in FIG. 18 with the passage of time.

  Each frame includes a telop portion 1811 including characters and the like and a non-telop portion 1812.

  Characters are displayed in the telop portion 1811, and the displayed characters move in a predetermined direction at a constant speed as time elapses. Specifically, the character is something like “Good morning. Let's stay healthy today.” This character moves to the left at a constant speed (scrolls). The “character” may include a figure or a symbol.

  The telop portion 1811 is generated so as to advance in a predetermined direction by a predetermined number of pixels every frame by image processing or the like by a computer. Therefore, if a frame is missing or overlapped during the reproduction of the content 1800, the viewer visually recognizes that the characters in the telop portion 1811 are temporarily advanced or stopped temporarily.

  Thus, the telop portion 1811 is generated on the premise that the telop portion 1811 is visually recognized so as to advance at a constant speed for the viewer. When many frames are reproduced without missing or overlapping, if a few frames are missing or overlapped, the missing or duplicated frames are easily recognized by the viewer.

  On the other hand, the non-telop portion 1812 is a moving image acquired by shooting or the like, and is composed of a moving image that proceeds independently of the telop portion 1811. In a moving image acquired by shooting or the like, the movement of a subject on the moving image is rarely constant, and even if a frame is missing or overlapped, it is difficult for a viewer to recognize it.

  According to the playback control device in each of the above embodiments, it is possible to suppress the occurrence of missing or overlapping frames in the content to be played back. As a result, the viewing effect is improved for the viewer, in particular, the characters in the telop portion 1811 advance at a constant speed.

  Note that when storing a frame from the buffer 305 to the output memory 306, only a part of the frame may be stored. In this way, for example, the telop portion 1811 can be controlled to suppress the occurrence of frame loss or duplication, and the non-telop portion 1812 can be controlled not to perform the above control.

  If the content includes audio, the audio is typically synchronized with a non-telop portion 1812. Therefore, if control is performed so as to suppress the occurrence of missing or overlapping frames in the portion 1812 that is not a telop, there is a possibility that a deviation from the sound (so-called sound deviation) occurs. Therefore, by controlling or not controlling each part as described above, it is possible to achieve both the prevention of sound misalignment and the suppression of occurrence of frame loss or duplication.

  As described above, the playback control device 12 according to the present embodiment, when playing back a plurality of frames held by the storage, uses the counter value used by the device that generated and recorded the plurality of frames. Based on the update cycle, the vertical synchronization signal cycle of the device itself is adjusted. Thereby, it is possible to reproduce a plurality of frames held by the storage while suppressing the occurrence of missing or overlapping frames.

  In each of the above embodiments, each component may be configured by dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

  Although the playback control apparatus of the present invention has been described based on the embodiment, 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. .

  INDUSTRIAL APPLICABILITY The present invention can be used for a playback control apparatus that can suppress the occurrence of frame loss or duplication in content to be played back. Specifically, when the content received via the network is played back and when the content stored in the storage device is played back, the occurrence of missing or overlapping frames in the played content is suppressed. The present invention can be used for a reproduction control apparatus that can

1, 2 Reproduction Control System 10, 12 Reproduction Control Device 20 Reproduction Device 30 Transmitting Device 40 Signal Line 50 Network 101 CPU
102 Main memory 103 Storage 104 NIF
105 reproduction processing unit 301 control unit 302 synchronization signal generation unit 303 signal output unit 304 timer 305 buffer 306 output memory

Claims (11)

A reproduction control apparatus for causing a reproduction apparatus to reproduce content including a plurality of frames,
A reproduction counter value that is a counter value indicating the timing at which the frame should be reproduced is added to each of the plurality of frames.
The playback control device
A timer that manages the current counter value, which is a counter value that increases every predetermined time;
An output memory for sequentially holding each of the plurality of frames as a target frame;
A synchronization signal generation unit that periodically generates a vertical synchronization signal and outputs the generated vertical synchronization signal to the playback device;
A signal output unit that outputs the target frame held in the output memory to the playback device in synchronization with the vertical synchronization signal;
A difference value between the reproduction counter value added to the target frame and the current counter value when the signal output unit outputs the target frame is calculated, and the plurality of frames are calculated based on the calculated difference value. A control unit that controls to increase or decrease the period of the vertical synchronization signal so that a difference value calculated for a subsequent frame after the target frame falls within a predetermined appropriate range. The controller is
A value obtained by subtracting the current counter value when the signal output unit outputs the target frame from the reproduction counter value is calculated as the difference value.
(I) when the difference value is positive, increase the period of the vertical synchronization signal;
The reproduction control apparatus according to claim 1, wherein (ii) when the difference value is negative, the period of the vertical synchronization signal is decreased. The control unit calculates a plurality of difference values, calculates a statistical difference value by statistically processing the calculated plurality of difference values, and uses the calculated statistical difference value as the difference value to perform the vertical synchronization The reproduction | regeneration control apparatus of Claim 1 or 2 which increases / decreases the period of a signal. The reproduction control apparatus according to any one of claims 1 to 3, wherein the period of the vertical synchronization signal is increased or decreased only when the difference value deviates from the predetermined appropriate range. The playback control device is connected to be able to communicate with a transmitting device that holds the content via a network,
The playback control device according to any one of claims 1 to 4, wherein the control unit acquires the target frame from the transmission device via a network, and stores the acquired target frame in the output memory. The control unit further includes:
The timer is controlled so as to increase or decrease the predetermined time so that the current counter value when the frame is acquired falls within an appropriate delay range determined from the reproduction counter value added to the target frame. Item 6. The playback control device according to Item 5. The reproduction control device further includes:
Comprising a storage for holding the content;
The playback control apparatus according to any one of claims 1 to 4, wherein the control unit acquires the target frame from the storage, and stores the acquired target frame in the output memory. Each of the plurality of frames is a telop portion located at a common position in each of the plurality of frames, and includes a telop including characters that move at a constant speed in a predetermined direction in the telop portion when the content is played back The reproduction | regeneration control apparatus of any one of Claims 1-7 which has a part. The playback control device
further,
A buffer holding a predetermined number of frames of the plurality of frames;
The controller is
One frame of the predetermined number of frames held in the buffer, wherein the current counter value is included in a predetermined memory storage permission range determined from the reproduction counter value of the one frame The reproduction control apparatus according to claim 1, wherein the target frame is held in the output memory by storing the frame in the output memory. A reproduction control method in a reproduction control device for causing a reproduction device to reproduce content including a plurality of frames,
A reproduction counter value that is a counter value indicating the timing at which the frame should be reproduced is added to each of the plurality of frames.
The playback control device
A timer that manages the current counter value, which is a counter value that increases every predetermined time;
An output memory for sequentially holding each of the plurality of frames as a target frame;
The reproduction control method includes:
A synchronization signal generation step of periodically generating a vertical synchronization signal and outputting the generated vertical synchronization signal to the playback device;
A signal output step of outputting the target frame held in the output memory to the playback device in synchronization with the vertical synchronization signal;
A difference value between the reproduction counter value added to the target frame and the current counter value when the target frame is output in the signal output step is calculated, and the plurality of frames are calculated based on the calculated difference value. A control step of performing control to increase or decrease the period of the vertical synchronization signal so that a difference value calculated for a subsequent frame after the target frame falls within a predetermined appropriate range.   A program for causing a computer to execute the reproduction control method according to claim 10.

Images