JP6336083B2 - Video information reproducing apparatus and reproducing method - Google Patents

Description

  The present invention relates to a video information reproducing apparatus that receives a signal including video information data (hereinafter, may be described only as video data) through a network and reproduces the video, and in particular, the video data is transmitted to a plurality of display apparatuses. The present invention relates to frame control of a video signal for display.

  Conventionally, when playback of a video is instructed by a playback device, first, a process called demux, which is a process of separating (decoding) a multiplexed signal that has been channel-coded, is performed, and then the information source-coded signal is processed. Decoding processing is started. In the decoding process of the information source encoded signal, the encoded video data is reproduced by the decoder and displayed on the image display device.

  For video data playback synchronization, the decoder reads information related to the display time of the video frame included in the control information data of the received signal, and the video display synchronization is switched by switching the frame display based on the read time information. Have taken. This video reproduction synchronization method is performed based on the internal time measured by the hardware clock mounted on the video information reproduction apparatus.

  In general, the internal time has an error in the oscillation frequency of the crystal oscillator that operates the hardware clock of about several ppm to 100 ppm, and also changes under various conditions such as a load increase of the receiving terminal and temperature, humidity, and voltage. . If the error of the oscillation frequency of the crystal oscillator is about 20 ppm, a time difference of about 3 seconds occurs in one day.

  When a video information reproducing apparatus equipped with such a hardware clock is connected to a network and video data is distributed from a content server that distributes video data to a plurality of video information reproducing apparatuses, the content server and the video information reproducing apparatus If the clocks are different, processing such as data exchange between devices may not be performed properly. Therefore, the synchronization between devices is synchronized with an NTP (Network Time Protocol: hereinafter sometimes referred to as NTP only) that synchronizes the clock of each device with the correct time (hereinafter may be referred to as a reference time). I'm taking it.

  By using NTP, it is possible to adjust the clock of each device and synchronize the time, but if the time is suddenly changed, for example, if the video is being played back, the playback will be discontinuous or the end The problem of not being played back occurs.

  In order to solve such a problem, a method has been proposed in which a difference between relative time information of a reference time and a video information reproducing apparatus is detected, and video reproduction synchronization is performed based on the difference. For example, a plurality of I or P pictures that display the same contents as the final frame of the main part of the encoded video data read from the storage medium are added as playback synchronization frames after the final frame of the main part. There is a method of adjusting by changing the number of reproduction frames for reproduction synchronization in accordance with the time information of the reference time (see, for example, Patent Document 1).

  Further, as a method of correcting the hardware clock of the video information reproducing apparatus to match the reference time, in order to correct the hardware clock, the first clock is divided to generate and output the second clock. A scaler and a timer that generates internal time information based on the second clock are provided. Based on the time difference between the internal time and the reference time, and the length of a predetermined time to be set to the time adjustment, the division ratio of the scaler is There is a method of performing adjustment so that the internal time gradually approaches the reference time by adjusting every cycle of the second clock (see, for example, Patent Document 2).

JP 2011-114681 A JP 2010-107342 A

  However, the adjustment method according to Patent Document 1 has a problem that the processing load of the content server increases because the video data is processed on the content server and then distributed to a plurality of video information reproducing apparatuses. Further, when reproducing and displaying video data delivered from a customer in advance, as in the digital signage business, processing the customer data is also a problem.

  Further, the adjustment method according to Patent Document 2 can smoothly adjust the clock, but has a problem that it takes time to correct the hardware clock.

The video information reproducing apparatus according to the present invention includes a reference time detection unit that detects a reference time based on time information included in the control information data in a received signal including the video data and control information data of the video data, and an internal clock. An internal time detection unit for detecting a measured internal time; a comparison unit for comparing the reference time detected by the reference time detection unit with the internal time detected by the internal time detection unit; and the video data and an output update unit for changing the interval period for each frame of the image data so that the frame rate for the display of more than the frame rate for displaying the image data, the output update unit compares the comparison unit When it is determined from the result that there is no difference between the reference time and the internal time, the frame rate of the video data is twice as high. Every two frames in the frame for display was Mureto displays the same image information, when it is determined that the internal time than the reference time from the comparison result of the comparing portion is delayed, the next frame to display only one frame in displaying the image information different from the previous frame, the when it is judged that the SL internal time Ri by the reference time from the comparison result of the comparison unit is advanced, the display to display the same image information or 3 frames It is obtained by changing the time .

  According to the present invention, when a time difference between the time indicated by the hardware clock in the video information reproducing apparatus and the reference time of the content server is detected, the video data included in the received signal is increased or decreased by increasing or decreasing the number of display frames. The time difference can be reduced by changing the display time per frame.

  Further, since it is not necessary to process the video data in the content server, and the stored original video data can be distributed as it is, the processing load on the content server can be reduced.

It is a figure which shows notionally the structure of the whole video information reproduction | regeneration system concerning Embodiment 1 of this invention. 1 is a block diagram schematically showing a configuration example of a video information reproducing apparatus according to a first embodiment of the present invention. It is a figure which shows the frame display method when there is no difference between the reference time and the internal time of the video information reproducing apparatus. It is a figure which shows the display method of a frame when the internal time of a video information reproducing | regenerating apparatus is late compared with reference | standard time. It is a figure which shows the display method of a flame | frame when the internal time of a video information reproduction apparatus is advanced compared with reference | standard time. It is a flowchart which shows the video information playback method of a video information playback apparatus. It is a flowchart which shows the video information delivery method of a content server. It is a figure which shows notionally the structure of the whole video information reproduction | regeneration system concerning Embodiment 2 of this invention. It is a block diagram which shows the video information reproducing | regenerating apparatus concerning Embodiment 2 of this invention.

Embodiment 1 FIG.
Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  FIG. 1 is a block diagram schematically showing a video information playback system including a video information playback device and a content server that distributes a signal including video data. This will be described below with reference to the drawings. In the figure, a content server 50 that distributes video data and digital data including the control information data to a plurality of video information reproducing apparatuses is, for example, a LAN (Local Area Network; hereinafter, only LAN may be described). Via the network 51 constituted by the video information playback device 30, here, the first video information playback device 31, the second video information playback device 32, the third video information playback device 33, and the first The data is distributed to the four video information reproducing devices 34. Here, the first video information playback device 31, the second video information playback device 32, the third video information playback device 33, and the fourth video information playback device 34 have the same configuration and have the contents server 50. Each of them receives a signal including video data distributed from.

  The digital data distributed from the content server 50 to the video information playback device 30 includes, for example, video data, audio data, control information data thereof, server time information data, and communication availability of the video information playback device. Data to be confirmed. In the following, it is assumed that digital data is distributed on the network 51 by broadcast distribution using UDP (User Datagram Protocol; hereinafter, only described as UDP). Although a signal composed of digital data is assumed here as a transmission signal, the signal is not limited to digital data. Analog data using amplitude modulation or frequency modulation may be transmitted.

  FIG. 2 is a block diagram showing the video information reproducing apparatus according to Embodiment 1 of the present invention, here, the first video information reproducing apparatus. The configuration of other video information playback apparatuses is the same. In the figure, the video information playback apparatus 30 will be described by taking the first video information playback apparatus 31 as an example, but the same applies to other video information playback apparatuses, and the video data distributed from the content server 50 is the same. When the decoding function and the delay or advance of the time measured by the internal clock of the video information reproducing apparatus 30 with respect to the content server 50 are detected, the delay and advance time information is stored, and the unit included in the distributed video data By increasing the number of frames per unit time displayed by the display unit 22 (hereinafter sometimes referred to as a display device) with respect to the number of frames per time, the display time per frame included in the distributed video data A video reproduction processing unit 23 having a function of determining whether to shorten the frame length, to increase the number of frames of the same image, or to perform other frame processing. , And a display unit 22 for displaying an image based on the frame processing result determined by the image reproduction processing unit 23.

  The display unit 22 is capable of receiving and displaying a video signal having a frame rate equal to or higher than that of video data distributed by frame rate conversion or the like. For example, when reproducing video data of 30 fps (Frames Per Second: hereinafter sometimes referred to only as “fps”), the display unit 22 is a display device capable of displaying video data of 30 fps or higher. For example, when a display device capable of displaying at 60 fps is used as the display unit 22, about 33.3 ms (1/30 s, which is a display time assumed per frame of the original video data before frame rate conversion is performed. Hereinafter, the actual display time per frame after the frame rate conversion in which the number of frames per unit time is doubled is shorter than “about” may be omitted. By using such a display device, when there is a delay in the reproduction of the video, the actual display time is made shorter than the display time of 33.3 ms per frame of the original video data, and the reproduction is performed. It is possible to recover the delay.

  In the above embodiment, the display unit 22 is assumed to be a display device capable of receiving and displaying a video signal having a frame rate higher than that of video data distributed by frame rate conversion or the like. Even if a display device can only receive and display a video signal with the same frame rate as the video data that the video data has, if the video playback progresses, the same frame is displayed continuously. By doing so, it is possible to correct the progress of the reproduction by making the display time longer than 33.3 ms, which is assumed per frame of the original video data.

The video reproduction processing unit 23 includes a data reception unit 10, a reference time detection unit 11, a data storage unit 13, a reproduction control unit 14, an output time measurement control unit 19, and an output time measurement unit 20. All of these are connected by a bus 21.

  The data receiving unit 10 receives, for example, MPEG-2, H.264, from the content server 50 connected to the video information reproducing apparatus 30 via a LAN. H.264 or H.264 Encoded video data such as H.265 is received.

  The reference time detection unit 11 detects the time information of the content server 50 because the time information is periodically transmitted from the content server 50 connected via the LAN by NTP. Here, the time indicated by the content server 50 detected by the reference time detection unit 11 is handled as the reference time. The time information detected here may be, for example, information that receives time information related to the absolute time indicated by the content server 50, or the content server 50 indicates information related to a frame that is currently scheduled to be played back. It may be a thing.

  The data storage unit 13 includes a buffer memory such as a RAM that temporarily stores the video data when the video information reproducing apparatus according to the first embodiment of the present invention receives the video data, and the first embodiment of the present invention. It is comprised by ROM etc. which memorize | store the operation | movement program etc. of the video information reproducing apparatus which concerns.

  The frame control unit includes a reproduction control unit 14 and an output time counting control unit 19.

  The reproduction control unit 14 constitutes a part of a frame control unit that performs frame reproduction control. The playback control unit 14 decodes the encoded video data, compares the reference time information of the content server 50 with the time information related to the internal clock of the video information playback device 30, and detects a delay or advance of playback timing. When is performed, the number of frames displayed and the display time are controlled according to the amount of delay or advance.

  The output time counting control unit 19 controls a display time per frame and constitutes a part of a frame control unit that performs frame reproduction control. The output time counting control unit 19 shortens or lengthens the display time of the display frame in combination with the control of the number of frames by the playback control unit 14 asynchronously with the playback display time for each frame of the video data during video playback. To do.

  The output time counting unit 20 includes a hardware clock and the like, has time measuring means, and measures the time when the frame display time is shortened or lengthened according to the control of the reproduction control unit 14.

  The reproduction control unit 14 includes a video decoder 15, a comparison unit 16, a storage unit 17, and an output update unit 18.

  The video decoder 15 receives MPEG-2, MPEG-4, H.264 received by the data receiving unit 10. H.264 and H.H. Video data that has been compression-encoded such as H.265 is decoded.

  The comparison unit 16 compares the time information of the content server 50 received by the reference time detection unit 11 with the time information used as a reference for display control of the video information reproducing apparatus 30, and delays video display timing with respect to the content server 50. Or advance detection.

  The storage unit 17 stores the delay or advance time of the video display timing of the video information reproducing device 30 detected by the comparison unit 16.

  The output update unit 18 changes the frame output time to an integral multiple of the display time per frame that can be displayed by the display device. For example, when displaying 30 fps video data using a display device capable of displaying video data at 60 fps, the display time of one frame is 16.7 ms (1/60 s), 33.3 ms (2/60 s). ) 50.0 ms (3/60 s), 66.7 ms (4/60 ms). Based on the delay or advance of the display timing of the video information reproducing apparatus 30 stored in the storage unit 17, the frame display time is determined so that the output time of each frame is not set to 0 and no frame drop occurs.

  In the conventional video reproduction apparatus, synchronous reproduction is performed according to the decode time and display start time for each frame included in the video data with reference to time information of the hardware clock. Therefore, when playing back 30 fps video data, the frame display start time is in increments of 33.3 ms (1/30 s), so the frames are switched at 33.3 ms. However, since the hardware clock runs on its own and keeps timing, it results in the time being shifted from the reference time of the content server or the video information reproducing apparatus installed in parallel.

  Therefore, in the video information reproducing apparatus according to Embodiment 1 of the present invention, a display that does not refer to the display start time information included in the received data and that can reproduce a frame rate equal to or higher than the frame rate of the received video data. By using the device, the frame display time is changed, and the time difference from the content server 50 as the reference time information is reduced. When displaying still images having the same image, content can be added or deleted by adding or deleting frames even when using a display device that can display at the same frame rate as the frame rate of the received video data. It is possible to adjust the timing of switching so that the hardware clock and the reference time match, but for moving images with different information for each frame, it prevents frame dropping and smoothness without any sense of incongruity Further, it has an effect of achieving moving image reproduction.

  FIG. 3 is a schematic diagram showing the relationship between the frame structure of video data and the playback frame when there is no time difference between the content server and the video information playback device. In the figure, the frame rate of video data is 30 fps, and the display device is a display device that can display at a frame rate of 60 fps. The frame rate of the video data is 30 fps, and the frame is switched every 33.3 ms. On the other hand, since the display device can cope with a frame rate of 60 fps, it is possible to switch frames every about 16.7 ms (1/60 s, hereinafter, “about” may be omitted). For this reason, in a display device that performs vertical synchronization at 16.7 ms (1/60 s), an image transmitted in one frame at the time of transmission is displayed in two frames having the same image information.

  FIG. 4 is a diagram showing a processing method on the video information playback apparatus side when it is detected that the frame display timing of the video information playback apparatus is delayed by, for example, 33.3 ms with respect to the reference time of the content server. is there. In the figure, when 30 fps received data is reproduced, one frame is originally switched at 33.3 ms. For example, when displaying on a receiving device capable of displaying at a frame rate of 60 fps, one frame is transmitted at the time of transmission. The displayed image is displayed in two frames having the same image information. In this case, in order to reduce the time difference between the reference time and the internal time based on the hardware clock, the predetermined image information is displayed in one frame, so that the original display in two frames is performed in one frame. Thus, the time of 16.7 ms (1/60 s) for one frame can be shortened, and the delay can be eliminated. By performing this for two predetermined images, the time of 33.3 ms for two frames can be shortened, and the delay can be eliminated. In this case, a frame drop that does not display any image information of a specific image does not occur, and all image information is displayed without fail. Further, the display time is shortened by setting the amount of change below the resolution in the time axis direction for the human eye image, so that the frame display timing of the video information reproducing apparatus 30 is delayed with respect to the reference time of the content server 50 without a sense of incompatibility. If it happens, you can correct it.

  In FIG. 4, in order to avoid dropping frames, the display time is halved for a predetermined plurality of frames. However, for still images in which images having the same content continue over a plurality of frames, When a still image is displayed for a certain period of time and switched, a frame drop may occur. In such a case, it is possible to cope with a simple process of not displaying a predetermined frame without performing a complicated process of reducing the display time to ½.

  FIG. 5 is a diagram showing a frame display method when it is detected that the frame display timing of the video information reproducing apparatus is advanced by, for example, 33.3 ms with respect to the reference time of the content server. In the figure, when 30 fps received data is reproduced, one frame is originally switched at 33.3 ms. For example, when displaying on a receiving device capable of displaying at a frame rate of 60 fps, one frame is transmitted at the time of transmission. The displayed image is displayed in two frames having the same image information. In this case, in order to reduce the time difference between the reference time and the internal time based on the hardware clock, the predetermined image information is displayed in 3 frames, so that the original display in 2 frames is more than that. Since the frame is displayed, the time of 16.7 ms (1/60 s) for one frame can be shortened, and the progress of that time can be eliminated. By performing this for two predetermined images, the time of 33.3 ms for two frames can be shortened and the advance can be eliminated. Here, although it performed with respect to two predetermined images, progress can also be eliminated by displaying four predetermined frames with respect to one predetermined image. Needless to say, if the advance width is large, the number of predetermined images can be set to 4 or more, or a predetermined image can be set to 4 frames or more.

  Next, a sequence until the video data distributed from the content server is played back by the video information playback device will be described. When a request for data transmission for starting playback is issued from the user to the content server 50, the content server 50 sends the first video information playback device 31, the second video information playback device 32, and the third video information. Transmission of video data and the like is started by broadcast to the playback device 33 and the fourth video information playback device 34. This reproduction start request may be made, for example, by sending a signal from any of the video information reproducing apparatuses.

  FIG. 6 is a flowchart showing a processing sequence of each video information playback device for synchronizing playback of a plurality of video information playback devices. In the figure, at step ST1, the content server 50 sends MPEG-2, H.264. H.264 and H.H. When video data such as 265 is received by the data receiving unit 10, the video decoder 15 in the playback control unit 14 starts decoding the video data.

  Next, when the reference time detection unit 11 receives reference time information in step ST2, the process proceeds to step ST3. For example, the time information is transmitted from the content server 50 every 10 seconds. The time information of the content server 50 received in this step may be, for example, time information related to the absolute time indicated by the content server 50, or the content server 50 is currently scheduled to be played back. Information indicating a frame may be indicated. When the time information of the content server 50 is not received by the reference time detection unit 11, the process proceeds to frame display time setting in step ST9.

  Next, in step ST3, the comparison unit 16 acquires the internal time information from the hardware clock operating in the video information reproducing device 30, and the time information of the content server 50 received by the reference time detection unit 11, The internal time information is compared, and in step ST4, a deviation (difference time) ΔT (ms) of the internal time with respect to the reference time is obtained. The internal time information is stored in the storage unit 17.

At this time, assuming that the time information of the content server 50 is the reference time and the time information of the video information reproducing apparatus 30 is the internal time, the difference time ΔT is calculated by the following formula 1.
[Equation 1] ΔT = internal time−reference time or less, the difference time ΔT is assumed to be a value with “ms” as a unit.

  Next, in step ST5, the value of ΔT is determined. If ΔT exceeds a predetermined threshold other than 0 and becomes a value that requires correction, the process proceeds to step ST6. If ΔT is less than or equal to the predetermined threshold value, time correction is unnecessary and the process proceeds to step ST9. In the video information reproducing apparatus according to Embodiment 1 of the present invention, the adjustment time is discontinuous because the delay time is adjusted by increasing or decreasing the frame. Therefore, even if ΔT is other than 0, if the display time of the frame to be increased / decreased is less than half, only the increase / decrease of a predetermined frame increases the time difference. If the time is set to half the time, and the value is equal to or less than the threshold value, the adjustment may not be performed and the process may proceed to step ST9. However, it goes without saying that finer time adjustment is possible by increasing or decreasing a plurality of predetermined frames as the number of frames that can be displayed per second is larger.

  When there is a difference between the reference time and the internal time and correction is necessary, first, the comparison unit 16 determines whether the ΔT is positive or negative. Based on the value of ΔT, the output time counting control unit 19 determines the display time. The frame display time is changed based on the difference correction amount A, which is an integer multiple of the frame period at which the display device does not drop a frame, with an integer multiple of the frame period that can be displayed by the display device as a unit of the difference correction amount A. . When the frame rate that can be displayed by the display device is 60 fps, the difference correction amount A is an integer multiple of 16.7 ms.

  When the source of video data with a frame rate of 30 fps is displayed on a display device that can display at a frame rate of 60 fps, and the video information playback device 30 is delayed by 33.3 ms compared to the reference time, With respect to two frames, it is possible to recover the delay of 33.3 ms by displaying only one frame where two frames are originally displayed and shortening the display time to 16.7 ms.

  When ΔT is negative, that is, when the internal time is delayed, if the difference is 16.7 ms or more, the time is corrected by distributing the difference over one frame or a plurality of frames. On the other hand, when the difference is less than 16.7 ms, the time is not corrected, and the process is not performed until the difference becomes 16.7 ms or more.

  When ΔT is positive, that is, when the internal time is advanced, if the difference is 16.7 ms or more, the time is corrected by distributing the difference over one frame or a plurality of frames. . On the other hand, when the difference is less than 16.7 ms, the time is not corrected, and the processing is not performed until the difference becomes 16.7 ms or more.

  The time correction when the difference time ΔT is less than ± 16.7 ms may be performed when ΔT is 8.3 ms or more, which is half of 16.7 ms. By correcting the time each time a difference of 8.3 ms or more is detected, the difference from the reference time can always be kept within ± 8.3 ms, and the time correction accuracy can be further improved.

In step ST6, a difference correction amount A is determined.
When the difference ΔT is outside the range of ± 16.7 ms, the difference correction amount A, the display frame number B in units on the display device side, and the carry-over error C are determined. At this time, the difference ΔT is expressed by [Formula 2].
[Formula 2] ΔT = B frame × 16.7 ms + C
The values of B and C satisfying [Formula 2] are determined, and display is performed by adding / subtracting ± B frames from the original display time. At this time, C becomes a “remainder” value, which is 16.7 ms or less.
Therefore, the difference correction amount A is calculated as [Equation 3], and the difference correction amount A is corrected with respect to the difference time ΔT.
[Formula 3] Difference correction amount A = B frame × 16.7 ms
Similarly, in order to increase the accuracy of time correction, the difference correction amount A, the display frame number B, and the carry-over error C may be determined when the difference time ΔT is outside the range of ± 8.3 ms.
In this case as well, the difference ΔT is calculated as in [Formula 4].
[Formula 4] ΔT = B frame × 16.7 ms + C
The values of B and C satisfying [Equation 4] are determined, and display is performed by adding / subtracting ± B frames from the original display time. At this time, C becomes a “remainder” value, which is 16.7 ms or less.
Therefore, the difference correction amount A is calculated as [Equation 5], and the difference correction amount A is corrected with respect to the difference time ΔT.
[Formula 5] Difference correction amount A = B frame × 16.7 ms

  In step ST7, the comparison unit 16 detects the frame currently being reproduced. In the video information reproducing apparatus according to Embodiment 1 of the present invention, since the display time of the video data of each frame set in advance is not synchronized, the contents of the currently displayed frame cannot be known only by the reproduction time. . Therefore, the frame number of the frame currently being reproduced is acquired and stored in the storage unit 17.

  In step ST8, the time of the hardware clock of the video information reproducing apparatus 30 is corrected by adding or subtracting the time of the difference correction amount A from the original display time. By performing video playback without referring to the display time information of the video data, control is performed so that frames are not dropped, and video playback is not interrupted and video is not disturbed due to dropped frames. Also, if a frame drop occurs, the time difference can be corrected immediately.

  In step ST9, when the time is delayed from the predetermined frame display time (usually 33.3 ms) in the output time counting control unit 19 according to the difference correction amount A determined in step ST6, the playback time of the next frame is set to [ 33.3 ms-difference correction amount A], and when the time is advanced, the playback time of the next frame is set to [33.3 ms + difference correction amount A]. At this time, in order to set the frame playback time so as not to cause a frame drop, if the time is delayed, the difference correction amount A is determined so that the playback time of the next frame does not become zero. When the time is advanced, the display time is extended over a plurality of frames so as not to prevent smooth video reproduction. For example, when the time of 166 ms is advanced, the display time of one frame is not set to display of 199.3 ms (33.3 ms + 166 ms), but is displayed as 50.0 ms (33.3 ms + 16.7 ms) over 10 frames. To do. Even when a frame drop occurs, the time difference can be corrected immediately.

  Next, in step ST10, the reproduction time of the next frame determined in step ST9 is measured by the output time measuring unit 20, and the display unit 22 displays the video. At this time, in step ST11, it is determined whether or not to end this sequence. If the video data is reproduced to the end, the process ends. If the video data has not been reproduced to the end, the process is started again from step ST2.

  FIG. 7 is a flowchart showing a processing sequence of the content server in the video information reproducing apparatus 30.

  For example, when a request for data transmission for starting playback is issued from the control device set in advance by a signage installer or the like to the content server 50, the content server 50 broadcasts video data to the video information playback device 30. Start sending. This reproduction start request may be made by sending a signal from any of the video information reproducing apparatuses. When the above request is issued, the process of the content server proceeds to step ST20 and starts transmitting the video data to the data receiving unit 10 of the video information reproducing apparatus.

  Next, when it is determined in step ST21 that 10 seconds have passed since the transmission of the video data with reference to the server time, the time information of the content server 50 used as the reference time for the plurality of video information reproducing apparatuses is determined in step ST22. The data is transmitted to the reference time detection unit 11 of the playback device. If 10 seconds have not elapsed, the process proceeds to step ST23. In addition, although 10 seconds was demonstrated here as an example, it cannot be overemphasized that it can set arbitrarily not only 5 seconds, 15 seconds, 20 seconds, 30 seconds, and other 5 second units.

  After step ST22, the process proceeds to step ST23, and when the video information data is reproduced to the end, this sequence is ended. If the video data has not been reproduced until the end, the process starts again from step ST20.

  As described above, when a difference is detected between the reference time and the internal time of the video information playback device by using a display device that can play back at a frame rate higher than the frame rate of the received video data, it is displayed. It is possible to correct the playback timing of the video by adding or deleting frames.

  According to the first embodiment, the time information of the content server 50 is compared with the time information used as the reference for display control of the video information reproducing apparatus 30, and the delay or advance of the video display timing is detected with respect to the content server 50. When this is done, the detected time difference can be quickly reduced by changing the display time of the frame of the received video data.

  Furthermore, since the content server does not process the video data on the content server and the stored video data can be distributed as it is, there is an effect that the processing load on the content server can be reduced.

  In addition, since the display time of the originally scheduled frame of the received video data is changed, it is possible to synchronize the reference time with the time without causing a frame drop, and smooth video playback can be performed. effective.

  The video information reproducing apparatus according to Embodiment 1 of the present invention includes, for example, a display device mounted on a car, a streetcar, a bus, a train, and the like, a display device of a surveillance camera, and the like between a plurality of display devices. Thus, it is possible to synchronize the reproduction time between the display devices for displaying the video with high accuracy.

Embodiment 2
FIG. 8 is a block diagram schematically showing a video information playback system including a video information playback apparatus and a plurality of video information playback apparatuses. In the first embodiment, the content server is responsible for the distribution of the video data. However, in the second embodiment of the present invention, one representative video information reproducing device is responsible for the distribution of the video data. This will be described below with reference to the drawings. In the figure, the fifth image information playback device 35, for example, LAN (Local Area Network. Hereinafter, be referred to as a LAN is) via the configured network 51, the first video information playback device 31 The data is distributed to the second video information playback device 32, the third video information playback device 33, and the fourth video information playback device 34. Here, the first video information playback device 31, the second video information playback device 32, the third video information playback device 33, the fourth video information playback device 34, and the fifth video information playback device 35 are For example, it is assumed here that each video information reproducing device receives video data distributed from the fifth video information reproducing device 35.

  In the first embodiment, the reference time of the video information playback device 30 is set as the time of the content server 50 that is an external device. However, the first video information playback device 31 connected by a network is used as the reference time. The second video information playback device 32, the third video information playback device 33, the fourth video information playback device 34, and the fifth video information playback device 35 are averaged to obtain the first video Among the information reproducing device 31, the second video information reproducing device 32, the third video information reproducing device 33, the fourth video information reproducing device 34, and the fifth video information reproducing device 35, it is closest to the average value. It may be the internal time of the video information reproducing apparatus.

FIG. 9 is a block diagram showing a video information reproducing apparatus according to Embodiment 2 of the present invention, here, a fifth video information reproducing apparatus. In the figure, the portions denoted by the same reference numerals as those in the first embodiment are portions having the same configuration as that described in the first embodiment, and thus detailed description thereof is omitted here. Data transmitter 24, the first video information reproducing apparatus 31 is a fifth image information reproducing apparatus other than the video information playback device 35, the second video information reproducing apparatus 32, the third video information reproducing apparatus 33 and, Then, the data including the internal time information is distributed to the fourth video information reproducing device 34. For example, the time information of the internal time is transmitted every 10 seconds. In addition, although 10 seconds was demonstrated here as an example, it cannot be overemphasized that it can set arbitrarily not only 5 seconds, 15 seconds, 20 seconds, 30 seconds, and other 5 second units.

  The reference time determination unit 25 performs the first video information playback device 31, the second video information playback device 32, the third video information playback device 33, and the fourth video information via the network 51 shown in FIG. Receiving the signal including the time information of the internal time of the playback device 34 and the fifth video information playback device 35 and the ID information identifying each video information playback device, and playing back the video information whose internal time information is closest to the average value The device is detected and the reference time is determined.

  With the configuration as described above, in the video information playback apparatus according to Embodiment 2 of the present invention, the first video information playback apparatus 31 and the second video information playback apparatus connected via the network without using the content server. 32, any one of the third video information playback device 33, the fourth video information playback device 34, and the fifth video information playback device 35 performs the change of the content server, and thus the first embodiment. The same effect as can be obtained.

  Furthermore, in the video information playback apparatus according to Embodiment 2 of the present invention, the video data stored in the fifth video information playback apparatus 35 is transferred to the first video information playback apparatus 31 and the first The second video information playback device 32, the third video information playback device 33, and the fourth video information playback device 34 can be distributed and played back synchronously. Here, the case where the fifth video information reproducing device 35 fulfills the change of the content server has been described as an example, but other first video information reproducing device 31, second video information reproducing device 32, third Any one or more of the video information playback device 33 and the fourth video information playback device 34 may be used. In addition, here, a network in which five video information playback apparatuses are connected has been described as an example. However, if there are a plurality of video information playback apparatuses, more than that, for example, six, seven, ten, and more. Needless to say, the effects of the present invention can be obtained even if there are, for example, two, three, and four.

DESCRIPTION OF SYMBOLS 10 Data reception part 11 Reference time detection part 13 Data storage part 14 Playback control part 15 Video decoder 16 Comparison part 17 Storage part 18 Output update part 19 Output time clock control part 20 Output time clock part 21 Bus 22 Display part 23 Video | video reproduction | regeneration processing Unit 24 data transmission unit 25 reference time determination unit 30 video information playback device 31 first video information playback device 32 second video information playback device 33 third video information playback device 34 fourth video information playback device 35 fifth Video information playback device 50 Content server 51 Network

Claims (3)

A reference time detection unit for detecting a reference time based on time information included in the control information data in a reception signal including the video data and control information data of the video data;
An internal time detector for detecting the internal time measured by the internal clock;
A comparison unit that compares the reference time detected by the reference time detection unit with the internal time detected by the internal time detection unit;
And output update unit for changing the interval period for each frame of the image data to display the video data at a frame rate for display or frame rate of the video data,
With
The output update unit
When it is determined from the comparison result of the comparison unit that there is no difference between the reference time and the internal time, two frames are the same in the display frame having a frame rate that is twice the frame rate of the video data. Display image information,
When it is determined from the comparison result of the comparison unit that the internal time is delayed from the reference time, only one frame is displayed and image information different from the previous frame is displayed in the next frame,
Wherein when it is judged that the SL internal time Ri by the reference time from the comparison result of the comparison unit is advanced, the video information reproducing apparatus to change the display time to display the same image information or three frames. The comparison unit obtains a time difference between the reference time and the internal time as the comparison result,
The output update unit is configured so as to reduce the absolute value of the time difference, the video information reproducing apparatus according to claim 1, wherein the determining the integer in several times integer. A reception step of receiving a reception signal including video data and control information data of the video data;
A reference time detecting step of detecting a reference time based on time information included in the control information data;
An internal time detection step for detecting the internal time measured by the internal clock;
A comparison step for comparing the reference time detected in the reference time detection step with the internal time detected in the internal time detection step;
An output update step of changing a display time of each frame of the video data so as to display the video data at a display frame rate equal to or higher than a frame rate of the video data;
Have
In the output update step,
When it is determined from the comparison result of the comparison step that there is no difference between the reference time and the internal time, two frames are the same in the display frame having a frame rate twice as high as the frame rate of the video data. Display image information,
When it is determined from the comparison result of the comparison step that the internal time is delayed from the reference time, only one frame is displayed and image information different from the previous frame is displayed in the next frame,
Wherein when the front SL internal time Ri by the reference time from the comparison result of the comparison step is determined to proceed, the video information playback method of changing the display time to display the same image information or three frames.

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