JP2005328128A - Synchronous playback device - Google Patents

Abstract

An apparatus for reproducing a plurality of video data in different recording situations in synchronization with the shooting time of each video is obtained.
When starting synchronous playback of a plurality of video data from a playback start time ts303, the 1-stream video playback means 103a to 103n start playback from a single decodable frame immediately before the playback start time ts303, and start playback. When playback of the frames existing in the time interval up to time ts303 is completed, the video is paused. The synchronization control unit 105 monitors all received data, detects that all the one-stream video playback units 103a to 103n have played back the video before the playback start time ts303, and plays back all at once through the playback control unit 104. An instruction is given to start synchronous playback after the start time ts303.
[Selection] Figure 1

Description

  The present invention relates to a synchronous playback apparatus for synchronously playing back a plurality of video data recorded on a recording medium, for example, videos of a plurality of cameras having different frame intervals or shooting timings shot and recorded at a store or a road. Is used for simultaneous reproduction on multiple screens in synchronization with the time of shooting.

  In recent years, especially in surveillance, due to the worsening of crime, important surveillance points such as store entrances and frequent incidents are shot with multiple cameras, and monitoring is performed with multiple cameras to capture people and incidents without blind spots. Is beginning to spread. In addition, incidents may occur at the same time due to group criminals in large stores such as parlors or in station premises, and there is a way to view and check the images captured by multiple cameras at the time of the incident. It has been demanded.

  A conventional apparatus for synchronously reproducing a plurality of video data sets a certain time as a reference time, and the reproduction start position and the reproduction start timing of each video data are offset times between the reference time and the recording start time of the reproduction target data. (For example, refer to Patent Document 1). FIG. 8 shows a conventional synchronized playback apparatus described in Patent Document 1. In FIG.

  In FIG. 8, the media data input means 201 records the two input video data (video data 1 and video data 2) in association with the recording start time. Next, when the user sets a reference time, the data integration unit 202 adds and records offset information of the reference time and the recording start time of each video data to each video data.

  Next, the data reproduction means 203 inquires the time conversion means 204 about the reproduction start position when the video data 1 and the video data 2 are synchronously reproduced from the reference time. Here, the time conversion means 204 refers to the offset time recorded in each video data, calculates the playback start time of each video data, and outputs information on the playback start position and playback start timing to the data playback means 203. To do. Next, the data reproduction means 203 outputs the offset time to the master timer 206, and starts reproduction from the reproduction start timing and reproduction start position received from the time conversion means 204.

For example, when video data 1 is video data recorded from time “8:58:00” and video data 2 is video data recorded from time “9:05:00”, the user sets the reference time as the reference time. When “9: 00: 00: 00” is set, “−0: 02: 00” and “+0: 05: 00” are recorded in each video data as offset time information with respect to the reference time. When reproduction of this video data is started from the reference time “9: 00: 00: 00”, the video data 1 starts to be reproduced from a video two minutes after the recording start time of the video data 1, while the video data 2 Does not play the video for the first 5 minutes, and starts playing the video data 2 when the elapsed playback time managed by the master timer 206 reaches 5 minutes.
JP 2002-262233 A (5th and 6th pages, FIG. 1)

  However, the conventional synchronized playback apparatus is not video data recorded at a high frame rate such as 30 fps recorded at 30 frames per second, but thinned video data or 0 recorded at 1 frame per 2 seconds. When applied to video data recorded at a low frame rate such as .5 fps, there are the following problems.

  In the conventional synchronized playback device configuration, when playback starts from the reference time, if the recording start time of the video data to be played is earlier than the reference time, playback starts from the position where the offset time has elapsed from the beginning of the video data. To do. However, in the thinned video data, there is a case where a frame corresponding to the time calculated as the reproduction start position does not exist, and the operation method in that case is not specified.

  If playback is started from the frame closest to the time calculated as the playback start position, the difference time between the time specified by the time conversion unit 204 as the playback start position and the time information of the frame actually set as the playback start frame. Only time synchronization with other video data will be lost.

  For example, FIG. 9A shows video data that is simultaneously recorded from time t0 at 30 fps for camera A and 10 fps for camera B, and FIG. 9B shows from time t4 in FIG. 9A. The video data in the case of reproducing the recorded video of camera A and camera B is shown.

  In FIG. 9A, camera A records a frame FA0 at 1/30 seconds, frame FA0 at time t0, and frame FA1 at time t1, and camera B records frames at time t0 at 1/10 seconds. Frame FB1 is recorded at FB0, time t3.

  Next, when the time t4 of the recorded video data is designated and played back, the conventional synchronized playback device starts playback from the frame closest to the time calculated as the playback start position. Playback starts at a 1/30 second interval from the frame FA4 corresponding to the time t4. Since there is no frame corresponding to the time t4 for the camera B, the playback starts at a 1/10 second interval from the frame FB1 at the time t3. It will be. For this reason, camera B performs playback for 1/30 seconds ahead of camera A, and cannot perform synchronized playback.

  As described above, in the conventional synchronized playback device, a method for realizing synchronized playback of a plurality of video data having different recording start times has been proposed. There was a problem that playback cannot be started while maintaining synchronization with video data having different intervals.

  In the conventional configuration, when the video data is recorded in an encoding format including a frame (I frame) that cannot be decoded independently such as MPEG, the playback start position is determined only by the offset time information with respect to the reference time. In some cases, the playback start frame may be an I frame, and a playback video cannot be obtained until the next independently decodable frame (P frame).

  Also, in the conventional synchronized playback device, when playback is started from the reference time, if the recording start time of the video data to be played is after the reference time, the playback of the video data is started after starting the synchronization from the reference time. Video display starts at the time when it should be. For this reason, the user does not know whether the video is not displayed due to some trouble, whether there is no video data, or whether it is displayed over time. Had the problem of giving anxiety.

  In addition, when browsing video data shot and stored for monitoring purposes, there is a demand for browsing from the previous video frame. However, in the conventional synchronous playback device, video after the time set as the start position is played back. Since it is a mechanism, it has a problem that it is insufficient as a monitoring application.

  An object of the present invention is to solve the problem of the conventional synchronous reproduction device, and to provide a synchronous reproduction device that realizes synchronous reproduction of a plurality of stored videos having different video frame intervals and photographing timings.

  In order to solve the conventional problem, in response to a request to start synchronous playback of multiple video data, a function that starts playback from a frame that can be independently decoded immediately before the playback start time for each video data, and by the playback start time 1-stream video playback means having a function of pausing when an existing frame has been played back, and detecting that playback of the video before the playback start time has been completed in all video data being played back synchronously , Comprising a synchronization control means for instructing all-stream video reproduction means to resume synchronous reproduction, and each one-stream video reproduction means receives a frame to be reproduced next in response to an instruction to resume reproduction from the synchronization control means. The video is sent after waiting for the difference time from the playback start time.

  With this configuration, it is possible to resume reproduction after synchronizing the video data after reproducing the video immediately before the start time in accordance with the recording status of the video data.

  According to the synchronous playback apparatus of the present invention, video existing after the specified time can be synchronized and played back regardless of the video format and recording status, and the video before the specified time can be displayed all at once. it can.

  According to a first aspect of the present invention, there is provided input means for inputting a reproduction start time of video data, a recording medium for recording a plurality of video data having different shooting conditions together with the shooting conditions, and the shooting of the plurality of video data. A frame to be reproduced from the recording medium is searched based on a condition, and a frame of video data photographed before the reproduction start time is reproduced without depending on the photographing condition, and is photographed after the reproduction start time. Frames of video data are reproduced by one stream video reproduction means depending on the photographing conditions, and synchronization control means for outputting video data reproduced depending on the photographing conditions after the reproduction start time to a display means, By playing back video data before the playback start time without depending on the shooting conditions, multiple video data with different shooting conditions can be played simultaneously. When raw, with the effect that all the image data can be shortened the time to ready display.

  According to a second aspect of the present invention, the one-stream video playback means includes a configuration for playing back the video data after the playback start adjustment time calculated using the video data shooting conditions and the playback start time, A plurality of video data having different shooting conditions can be reproduced according to each shooting condition.

  According to a third aspect of the present invention, the 1-stream video playback means further includes a coded video decoding means, and when the video data is composed of a frame that can be decoded independently and a frame that cannot be decoded independently, the decoding is performed. The means includes a configuration in which decoding is performed from a frame that can be decoded independently before the reproduction start time and is closest to the reproduction start time, and the processing amount of video data before the reproduction start time can be reduced. Has an effect.

According to a fourth aspect of the present invention, the 1-stream video playback means further includes an encoded video re-encoding means, wherein the 1-stream video playback means is before the playback start time, and a frame closest to the playback start time is present. In the case of a frame that cannot be independently decoded, the decoding means sequentially decodes the frame from the independently decodable frame, and re-encodes and outputs only the frame that cannot be independently decoded that is closest to the reproduction start time. In addition, since the video data sent to the display terminal is reduced from a plurality of frames to one frame, the transmission amount of the video data can be reduced.

  According to a fifth aspect of the present invention, the one-stream video playback means searches for a frame to play back the plurality of video data from the recording medium based on the shooting conditions, and video data shot before the playback start time The frame of the video data is played back at the same time without depending on the shooting conditions, and the frame of the video data shot after the playback start time is played back according to the shooting conditions and synchronized. The control means further includes a configuration for outputting to the display means the video data before the reproduction start time reproduced at the same time, and can display the video before the reproduction start time in a short time. Has an effect.

  According to a sixth aspect of the present invention, the one-stream video playback means plays back a frame indicating that there is no recorded video when a frame of video data shot before the playback start time is not recorded on the recording medium. When the video data is not displayed, it is easy to guess that some abnormalities such as a network failure or a server error have occurred, and the camera recording status for the user It has the effect of making it easier to grasp.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of a synchronous playback apparatus for synchronously playing back video based on a plurality of different shooting conditions according to Embodiment 1 of the present invention. In the figure, the dotted line arrows indicate the flow of control messages, and the solid line arrows indicate the flow of video data.

  In FIG. 1, the synchronous playback apparatus includes a display terminal 101 including a display unit 101-1 for receiving and displaying a plurality of video data, and an input unit 101-2 for inputting a playback operation command. 1 stream video playback for searching and playing back the recording medium 102 that is recorded together with the shooting time or recording time of the video data and the frame of video data to be played back from the recording medium 102 based on the shooting time or recording time of the video data Means 103a-n and a playback control means having a function of receiving a playback operation command from the display terminal 101 and notifying the content of the command to the one-stream video playback means 103a-n according to the content of the playback operation command 104 and the playback frames from the one-stream video playback means 103a to 103n, and the playback control means 10 from the playback status of each video data. Composed of the synchronization control unit 105 for outputting a synchronous control signal to.

  Note that the shooting time of the plurality of video data is the time when the camera has shot, and the recording time is the time when the video data shot by the camera is input to the recording medium and the recording medium records the video data. When the video data cannot be transmitted by adding the shooting time information to the video data captured by the camera, the recording time can be added to the recorded video because the time is set by the recording medium.

  The recording medium 102 records, for example, videos from a plurality of cameras, and each video data is recorded together with the ID of the shooting camera, the shooting time, or the recording time. Note that the encoding format of the video data may be different for each camera, and video format information is also recorded.

The reproduction control unit 104 has a function of receiving the reproduction operation command from the display terminal 101 and controlling the one-stream video reproduction units 103a to 103n. Playback operation commands include start, stop, and pause of synchronous playback, as well as fast forward, slow, and reverse playback. The synchronous playback start command includes information on the shooting camera ID to be synchronously played and playback parameters such as playback start time, playback direction and speed. At the start, the playback control means 104 outputs one stream video for each video data. Reproducing means 103a to 103n are configured. In addition, when an operation command such as pause or fast forward is received from the display terminal 101, it has a function of notifying the one-stream video playback means 103a to 103n.

  The 1-stream video playback means 103a to 103n are responsible for playback processing by one 1-stream video playback means 103 for one video, search for a playback target frame from the recording medium 102, and perform synchronization control means 105 in units of frames. To send.

  Here, the frame transmission timing mainly supports two methods. First, the frame is transmitted at an interval proportional to the frame interval of the recorded frame, and second, the frame of the recorded frame. There is a method of playing at intervals that do not depend on the interval.

  At the start of synchronized playback, the specified playback start time is synchronized with the section that plays back the frames that exist in the time section from the video before the playback start time to the start time (hereinafter referred to as “pre-playback section”). In accordance with an instruction from the control means 105, playback is performed in two stages of a section for playing back video after the start time.

  In this embodiment, as an example, the playback of the video in the pre-playback section is played back at an interval that does not depend on the frame interval of the recorded frame, and the video after the playback start time is the interval of the frame interval of the recorded frame To play on. When fast-forwarding or rewinding video data, it is played back at an interval proportional to the frame interval.

  FIG. 2 shows an operation flow at the time of pre-reproduction of the one-stream video reproduction means 103a to 103n.

  First, in S501, in response to a start command, a playback start frame (pre-play start frame) in the pre-play section is searched. Note that the pre-reproduction start frame is a single-decodable frame closest to the start time within a certain time range before the start time. Next, in S502, it is determined whether a search result frame has been found. Next, in S503, the frame searched in S501 is acquired from the recording medium 102 and set as a transmission decision frame.

  Next, in S504, if a pre-reproduction start frame is not found, an “NR (Not Recorded) image” indicating that no video exists in the section to be reproduced is set as a transmission decision frame. At this time, the “NR image” is set instead of the video at the playback start time, and the value of the playback start time is set as the time code.

  Next, in S505, a frame to be reproduced next is searched. Hereinafter, the frame to be transmitted next is referred to as a “prefetch frame”. Next, in S506, it is determined whether a prefetch frame is found. Next, in S507, if a prefetch frame exists, the frame is acquired.

  Next, in S508, if there is no frame to be reproduced, “NR image” is set as a prefetch frame. At this time, the operation code of the one-stream video reproduction means 103d is a time code given to the “NR image” as reproduction start time + α time. Here, α is a positive value.

  In step S509, it is determined whether the time code of the frame exceeds the reproduction start time for the set prefetch frame.

Next, in S510, if it is determined in S509 that the time code of the pre-read frame exceeds the reproduction start time, the transmission decision frame is the last frame of pre-reproduction, so that the pre-reproduction section is added as information to be added to the transmission decision frame. Is given a flag (hereinafter referred to as pre-reproduction completion flag).

  Next, in S511, the transmission determination frame is transmitted to the synchronization control means 105.

  Next, when the time code of the prefetch frame does not exceed the reproduction start time in S512, a transmission decision frame is transmitted to the synchronization control means 105.

  Next, in S513, the prefetch frame is replaced with a transmission decision frame, and the process proceeds to S505 to search for the next prefetch frame. After S511, the one-stream video playback means 103a-n sequentially plays back the frames in the pre-playback section, and then enters a paused state. The pause state means that the one-stream video playback means 103a-n pauses the playback operation. State.

  FIG. 3 shows an operation flow of the 1-stream video playback means 103a to 103n when receiving a synchronous playback start instruction from the synchronous control means 105 in a state of being paused after the playback of the pre-playback section.

  Here, at the start of synchronous playback, since one frame is always prefetched in the pre-playback period, the next stream to be transmitted is acquired in the one-stream video playback means 103a to 103n.

  First, in S601, in response to an instruction to start synchronous playback, a time (ideal transmission time) at which the acquired prefetch frame is to be transmitted is calculated. The ideal transmission time is a time that is a difference time ahead of the time code of the prefetch frame and the reproduction start time from the current time.

  Next, in S602, the current time is acquired. Next, in S603, the system waits for the difference time between the ideal transmission time and the current time. In step S604, a prefetch frame is sent out. Next, in S605, the subsequent playback frames are searched for frames to be played back in sequence.

  Next, in S606, the found frame is acquired. Next, in S607, an ideal transmission time is set at a time interval proportional to the frame interval of the recorded frame, and the process proceeds to S602 and is transmitted to the synchronization control means 105.

  The synchronization control means 105 receives the output data from the one stream video reproduction means 103 a to 103 n and sends it to the display terminal 101. At this time, each video data is monitored, and it is checked whether or not the pre-reproduction end flag has been given from all the video data. When it is detected that all the video data has reached the pre-playback end state, the synchronization control means 105 instructs the playback control means 104 to start synchronous playback of the video after the playback start time all at once. send.

  A specific operation flow is shown in FIG.

  First, in step S701, the synchronization control unit 105 monitors the input of video data sent from the one-stream video playback units 103a to 103n. If video data is input, the process proceeds to step S702 and no video data is input. In this case, the process proceeds to S701. In step S <b> 702, when a video is input, the synchronization control unit 105 checks information attached to the video data and checks whether the pre-reproduction completion flag is ON / OFF.

Next, in S703, when the pre-reproduction completion flag is OFF, the synchronization control unit 105 sends the input video data to the display terminal 101, and proceeds to S701. Next, in S704, when the pre-reproduction completion flag is ON, the synchronization control unit 105 updates the pre-reproduction completion status management data of each video data possessed by the synchronization control unit 105.

  Next, in step S705, the synchronization control unit 105 checks whether or not the playback of the pre-playback section has been completed for all video data based on the management data. If incomplete, the process proceeds to step S703. The transmitted video data is sent to the display terminal 101. In step S706, the synchronization control unit 105 transmits an instruction to start synchronous reproduction to the reproduction control unit 104 when reproduction of the pre-reproduction section is completed for all video data.

  In step S <b> 707, the input video data is sent to the display terminal 101. Next, in S708, it is checked whether or not input data has been received. If there is no received data, S708 is repeated. In step S709, the synchronization control unit 105 sends all data to the display terminal 101 when data is input.

  Next, the operation when a plurality of videos are synchronously reproduced from the time ts will be specifically described. FIG. 5 is described using four types of video data having different video formats, frame intervals, and shooting timings. The horizontal axis is an accumulation time axis to which each video is taken or recorded, and the frames recorded before and after the reproduction start time ts303 are drawn in an arrangement proportional to the recording interval. The video data reproduced by the one-stream video reproducing means 103a, b, d is a JPEG image, and the video data reproduced by the one-stream video reproducing means 103c is an MPEG video.

  When the user requests the start of synchronous playback, a playback start request is notified from the display terminal 101 of the user to the playback control means 104. The reproduction control unit 104 activates four one-stream video reproduction units 103a to 103d that reproduce four types of video data, and notifies the reproduction start time ts303 to be reproduced.

  The 1-stream video playback means 103a to 103d search for frames that exist within a certain time before the playback start time ts303 and that can be independently decoded (intraframe: I frame) closest to the playback start time ts303. To do. The 1-stream video playback means 103a detects the frame Ia2 in FIG. 5, the 1-stream video playback means 103b detects the frame Ib1, and the 1-stream video playback means 103c detects the frame Ic1. The 1-stream video playback means 103d is “no corresponding frame” because there is no frame before the playback start time ts303 to be searched.

  Next, after detecting the frame Ia2, the 1-stream video reproduction means 103a searches for a frame to be reproduced next. The next frame to be played back is the frame Ia3. Since this frame Ia3 is a frame after the playback start time ts303, a pre-playback end flag is added to the frame Ia2 and sent to the synchronization control means 105 for playback processing. Pause.

  Similarly, the 1-stream video reproduction means 103b also adds a pre-reproduction end flag to the frame Ib2, sends it to the synchronization control means 105, and pauses.

Next, when the one-stream video playback means 103c detects the frame Ic1 and searches for the next frame to be played back, the frame Pc2 is found. However, since the frame Pc2 is a video before the playback start time ts303, pre-playback is performed. The frame Ic1 is sent to the synchronization control means 105 without adding an end flag. After the transmission, the data of the frame Pc2 is acquired from the recording medium 102, the next frame to be reproduced is further searched, and this is repeated. Since it is detected that the next frame Pc4 is a frame after the reproduction start time ts303 when the frame Pc3 is taken into the one-stream video reproduction means 103c, the frame Pc3
A pre-completion flag is assigned to the data and sent to the synchronization control means 105, and then temporarily stopped.

  Next, the 1-stream video reproduction unit 103d transmits an “NR image” indicating that there is no video at a position to be reproduced because there is no frame to be transmitted. This NR image is sent with a pre-reproduction completion flag added and paused.

  The synchronization control unit 105 receives the playback video of the four cameras of the one-stream video playback units 103a to 103d, sends the received video data to the display terminal 101, and monitors the pre-play completion flag assignment status. When the data with the pre-reproduction completion flag is sent from all the 1-stream video reproduction means 103a to 103d, the synchronization control means 105 sends the video data after the reproduction start time ts303 to the reproduction control means 104. Outputs instructions for synchronous playback.

  The reproduction control unit 104 notifies the one-stream video reproduction units 103a to 103d when an instruction to start synchronous reproduction is input from the synchronous control unit 105.

  When the one-stream video reproduction means 103a receives the instruction to start synchronous reproduction issued from the synchronous control means 105, the one-stream video reproduction means 103a acquires the frame Ia3 to be transmitted next from the recording medium 102, and the time code of the frame Ia3 and the reproduction start time The frame Ia3 is transmitted after the elapse of the waiting time t1 shown in FIG. 2, which is the difference time of ts303. Subsequent frames are sequentially transmitted as frames Ia4, frames Ia5,... At intervals equivalent to the frame intervals at the time of recording.

  Similarly to the 1-stream video playback unit 103a, the 1-stream video playback units 103b to 103d transmit the frame Ib2, the frame Pc4, and the frame Id1, which are frames to be transmitted, after the standby times t2, t3, and t4 have elapsed, and play them back. continue.

  Next, FIG. 6 shows an actual playback / sending situation when the stored video of FIG. 5 is played back by the synchronous playback device of the present invention.

  FIG. 6 shows the playback images 401a to 401d of the cameras A to D, which are displayed in time series along the playback time of each frame. When receiving a playback start instruction, the 1-stream video playback means 103a to 103d corresponding to the cameras A to D simultaneously display a single decodable frame immediately before the playback start time ts303 as a pre-playback start frame. As for the one-stream video playback means 103c corresponding to the camera C, there are three frames Pc1, Pc2, and Pc3 in the time interval up to the playback start time ts303, and these are transmitted regardless of the recording time. After the playback to the frame Pc3 of the one-stream video playback means 103c, the display terminals 101 start to display the video after the playback start time ts303 all at once. At that time, the frames Ia3, Ib2, Pc4, and Id1 to be sent next to the one-stream video reproduction means 103a to 103d are sent to the synchronization control means 105 after the difference time between the time code of each frame and the reproduction start time ts303 has elapsed. Are displayed on the display terminal 101.

  According to such a configuration, in the pre-reproduction section before the reproduction start time ts303, intra frames are reproduced from all video data without considering the frame interval and the shooting timing, and then the synchronous reproduction section after the reproduction start time ts303 is started. This solves the problem that the playback start frame is immediately displayed in all playback videos regardless of the state of stored data, and the video has to wait until playback. In addition, synchronized playback after the playback start time ts303 can be realized regardless of the video format and recording status.

In this embodiment, the 1-stream video playback means 103a to 103n search for an intra frame closest to the playback start time ts303 among frames existing within a certain time before the playback start time ts303. The “fixed time” to be searched is set to 0 seconds, and all the video transmissions in the pre-playback section are set to “NR images”, and can be played back after the playback start time ts303.

  In the present embodiment, the reproduction in the time axis direction (forward direction) is described as an example of the reproduction direction, but the case of the reverse direction can also be applied. “Before time ts303” changes to “after playback start time ts303” depending on the playback direction, and “before playback start time ts303” refers to a time interval in the past from playback start time ts303 in the case of forward playback. In the case of direction reproduction, it indicates a time interval in the future from the reproduction start time ts303.

  In the present embodiment, reproduction of a plurality of video data is realized as one stream video reproduction means 103a to 103n for performing reproduction processing for each video data. However, a plurality of video data are simultaneously searched and reproduced. Reproduction means may be used.

(Embodiment 2)
Next, when the video encoding format includes a frame such as MPEG that cannot be independently decoded (hereinafter referred to as P frame or inter frame), and there are a plurality of playback frames in the pre-playback section, the one-stream video playback means 103a ˜n sequentially decodes frames from the I frame, and the display terminal 101 describes a synchronous playback device that transmits only one frame closest to the playback start time ts303 among the frames in the pre-playback section.

  Here, in order to reproduce the P frame, although not shown, the 1-stream video reproduction means 103a to 103n are provided with decoding means and re-encoding means therein.

  FIG. 7 shows an operation flow at the time of pre-reproduction of the one-stream video reproduction means 103a to 103n. In addition, the same code | symbol is used about the same process as FIG.

  First, in steps S501 to S509, in the same manner as in the first embodiment, the 1-stream video playback means 103a to 103n search for a frame that can be independently decoded immediately before the playback start time ts303, and transmit determination frames and prefetch frames. Search and retrieve

  Next, in S509, it is determined whether or not the time code of the prefetched frame is after the reproduction start time ts303.

  Next, when the time code of the prefetch frame is before the reproduction start time ts303 in S509, the process proceeds to S801, and when the time code of the prefetch frame is after the reproduction start time ts303, the process proceeds to S803.

  Next, in S801, when the prefetch frame belongs to the pre-reproduction section, the prefetch frame is decoded from the data of the transmission determination frame that is the I frame.

  Next, in S802, the decoded prefetch frame is replaced with a transmission decision frame, and the process proceeds to S504, where the above processing is repeated until the time code of the prefetch frame exceeds the reproduction start time ts303.

  In step S803, it is determined whether the transmission determination frame is encoded data. Here, if the transmission determination frame is encoded data in S803, the process proceeds to S510, and if it is not encoded data, the process proceeds to S804. Next, in S804, the transmission decision frame is re-encoded to generate a frame that can be independently decoded.

    Next, in S510, a pre-completion flag is added to the transmission decision frame. Next, in S511, the transmission determination frame is transmitted to the synchronization control means 105.

  In the multi-screen playback of MPEG-4 video, there are a plurality of frames in the pre-playback section like the video of camera C in FIG. 5 described in the first embodiment, and the video immediately before the playback start time ts303 specified by the user is displayed. Although there are cases where a plurality of frames are transmitted, in the second embodiment, by incorporating S801 to S804, the frame transmitted from the 1-stream video reproduction means 103c of the camera C to the synchronization control means 105 is displayed at the reproduction start time ts303. One frame obtained by changing the nearest frame Pc3 into an encoding format that can be independently decoded is transmitted. By changing the frame Pc3 to a frame that can be decoded independently, the display terminal 101 can decode the frame Pc4 that cannot be independently decoded based on the frame Pc3.

  Thereby, the video data transmitted to the synchronization control unit 105 and the display terminal 101 can be reduced from a plurality of frames to one frame. For example, when the synchronization control unit 105 and the display terminal 101 are connected via a network. For example, there is a merit that the transmission amount of video data is reduced. Also, for the user, only one frame is always displayed in the video of each camera with respect to the reproduction start time ts303 specified by the user, which is easy to understand.

  Next, the display terminal 101 displays all the frames received from the synchronization control means 105 when the video encoding format includes P frames such as MPEG that cannot be decoded independently and there are a plurality of playback frames in the pre-playback section. Instead, a synchronous playback apparatus is described in which received frames are sequentially decoded, and from that the frame closest to the playback start time ts303 in the pre-playback section is displayed.

  The configuration of the synchronized playback apparatus is the same as that in FIG. The operation of each means other than the synchronization control means 105 and the display terminal 101 is also the same, and the illustration is omitted.

  When the video data to which the pre-reproduction completion flag is given is input, the synchronization control unit 105 sends the video data to the display terminal 101 together with the flag information.

  The display terminal 101 performs the decoding process for all video frames received after the start of the synchronized playback, but displays only the frames after the frame with the pre-play completion flag on the display means 101-1.

  Thereby, when there are a plurality of frames such as an I frame, a P frame, and a P frame in the pre-playback section, it is possible to browse from the immediately preceding P frame. Further, P frames existing after the reproduction start time can be reproduced continuously.

  The synchronized playback device according to the present invention is a device capable of displaying a plurality of video data having different recording frame rates at different recording frame rates in time synchronization. In particular, in surveillance, important locations where people enter and exit are recorded at high frame rates using JPEG video, and in locations where people do not pass or where surveillance is less important, 1 frame is recorded every 3 seconds / sensor. The recording status varies depending on the shooting camera, such as recording only when the camera responds. In addition, even with a single camera, the recording status is often changed according to the time zone according to the presence / absence of a supervisor, the opening / closing time of a store, and the like. Thus, the apparatus is useful for synchronous reproduction of a plurality of video data having different recording forms.

  In recent years, with the spread of portable cameras such as still image / video cameras attached to mobile phones, digital cameras, and digital videos, the general public who witnessed the incident has been increasingly shooting the incident. Even in such a case, the device of the present invention can also reproduce the video of the surveillance camera provided in the store where the incident occurred and the video of the general public's shooting camera as described above in synchronization with time. It becomes possible.

  In the above embodiment, the playback start method for synchronously playing back images at the same time based on the time information of the shooting time or the recording time has been described. However, the method of the present invention can be applied to one video data. On the other hand, the present invention can also be applied to display images from time t1 and time t2 in synchronization.

The figure which shows the structure of the synchronous reproduction apparatus by Embodiment 1 of this invention. The flowchart which shows the operation | movement of the pre reproduction | regeneration of the 1 stream video reproduction | regeneration means by Embodiment 1 of this invention. The flowchart which shows the synchronous reproduction start of the 1 stream video reproduction | regeneration means by Embodiment 1 of this invention. The flowchart which shows operation | movement of the synchronous control means by Embodiment 1 of this invention. The figure which shows the recording condition of the camera made into reproduction object by Embodiment 1 of this invention The figure which shows transmission of the reproduction | regeneration frame of the synchronous reproduction apparatus by Embodiment 1 of this invention. The flowchart which shows the operation | movement of the pre reproduction | regeneration of the 1 stream video reproduction | regeneration means by Embodiment 2 of this invention. Configuration diagram of a conventional synchronized playback device (A) The figure which shows accumulation | storage of the video data by the conventional synchronous reproduction apparatus (b) The figure which shows reproduction | regeneration of the stream image | video by the conventional synchronous reproduction apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Display terminal 101-1 Display means 101-2 Input means 102 Recording medium 103a-n 1 stream video reproduction means 104 Playback control means 105 Synchronization control means 303 Playback start time 401a-d Playback video

Claims (7)

Input means for inputting the playback start time of video data, a recording medium for recording a plurality of video data with different shooting conditions together with the shooting conditions, and playing back the plurality of video data from the recording medium based on the shooting conditions A frame of video data shot before the playback start time is played back without depending on the shooting conditions, and a frame of video data shot after the playback start time is A one-stream video reproduction means for reproducing depending on the video and a synchronous control means for outputting to the display means video data reproduced depending on the shooting conditions after the reproduction start time. The synchronized playback apparatus according to claim 1, wherein the one-stream video playback means plays back the video data after a playback start adjustment time calculated using the video data shooting conditions and playback start time. The one-stream video playback means further includes a coded video decoding means, and when the video data is composed of a frame that can be decoded independently and a frame that cannot be decoded independently, the decoding means is before the playback start time. The synchronized playback apparatus according to claim 1, wherein decoding is performed from a frame that can be independently decoded that is closest to the playback start time. The 1-stream video playback means further includes a coded-video re-encoding means, wherein the 1-stream video playback means is before the playback start time and the frame closest to the playback start time is a frame that cannot be decoded independently 4. The synchronous reproduction apparatus according to claim 3, wherein the decoding means sequentially decodes the frames from the single decodable frame, re-encodes only the non-single decodable frame closest to the reproduction start time, and outputs the result. The one-stream video playback means searches for a frame to play back the plurality of video data from the recording medium based on the shooting conditions, and the frame of the video data shot before the playback start time depends on the shooting conditions Without replaying the frame of the video data at the same time, the frame of the video data shot after the playback start time is played back depending on the shooting conditions, and the synchronization control means further includes the same time 5. The synchronous playback apparatus according to claim 1, wherein the video data played back before the playback start time is output to display means. 6. The one-stream video playback means plays back a frame indicating that there is no recorded video when a frame of video data shot before the playback start time is not recorded on the recording medium. Synchronous playback device. A first step of inputting a reproduction start time of video data, and a frame for reproducing the plurality of video data from a recording medium in which a plurality of video data having different shooting conditions is recorded together with the shooting conditions based on the shooting conditions And a frame of video data shot before the playback start time is played back without depending on the shooting conditions, and a frame of video data shot after the playback start time is A synchronous reproduction method including a third step of reproducing depending on the photographing condition and a fourth step of outputting video data reproduced depending on the photographing condition after the reproduction start time to a display unit.

Images