JP2008092253A - Recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording and reproducing device which can improve operability. <P>SOLUTION: Image creation time and image recording time are assigned to each of a plurality of recorded JPEG (Joint Photographic Experts Group) files. Voice creation time and voice recording time are assigned also to each of a plurality of recorded voice groups. A CPU 44 specifies a voice block which has voice recording time satisfying a time condition between the image recording time of the reference JPEG file. The CPU 44 also specifies a voice block which has voice creation time satisfying a time condition between the image creation time of the reference JPEG file out of voice blocks after the voice block specified in the former processing. A JPEG file which is late from the reference JPEG file, is reproduced referring the image creation time. A voice block relating to the reproduced JPEG file, is reproduced referring the voice creation time. The reference JPEG file is redetermined when an error condition regarding continuity of the voice creation time is satisfied. By the means, the operability is improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a recording / reproducing apparatus, and more particularly to a recording / reproducing apparatus that is applied to, for example, a surveillance camera system and records / reproduces a plurality of image frames and a plurality of audio blocks.

An example of a conventional device of this type is disclosed in Patent Document 1. According to this prior art, moving image data is received from the network with a time code added, and audio data is also received from the network with a time code added. The received moving image data is output from the monitor via the frame buffer. The received audio data is temporarily stored in the audio output buffer. The audio output timing adjustment device inserts a silent period on the audio output buffer so that audio corresponding to the frame to be displayed on the monitor is output from the speaker according to the received time code and usage information of the audio output buffer. Or delete it.
JP-A-9-65303 [H04N 7/10, 5/93]

    However, in the prior art, the output timing of moving image data is defined only by the time code, and the output timing of audio data is adjusted according to the output timing of moving image data. Then, when the frame rate of the moving image data is extremely long (for example, 1 frame / 30 minutes) and a period in which no audio data is received appears intermittently, a phenomenon occurs in which the same image continues to be displayed for a long time. Such a phenomenon is problematic in terms of operability.

  Therefore, a main object of the present invention is to provide a recording / reproducing apparatus capable of improving operability.

  The recording / reproducing apparatus according to the first aspect of the present invention (200: reference numeral corresponding to the embodiment; the same applies hereinafter) includes the first image time information and the image / sound along the first time axis defining the image / sound recording time. First recording means (S5) for recording on the recording medium (52) a plurality of image frames each assigned with second image time information along the second time axis defining the creation time, along the first time axis Second recording means (S11) for recording on the recording medium a plurality of audio blocks each assigned with the first audio time information and the second audio time information along the second time axis, and the second audio means assigned to the reference image frame First specifying means (S33, S35) for specifying a sound block to which a first sound time information satisfying a time condition with one image time information is assigned from a plurality of sound blocks, assigned to a reference image frame Time condition with the second image time information Second specifying means (S39, S41, S43) for specifying an audio block to which the second audio time information satisfying the condition is assigned from the audio blocks after the audio block specified by the first specifying means, as a reference image frame Image reproduction means (S61) for reproducing a plurality of delayed image frames from the recording medium based on the second image time information, and a plurality of audio blocks related to the plurality of image frames reproduced by the image reproduction means as second audio time information. Re-determination to re-determine the reference image frame when an error condition relating to continuity of the creation / recording time is satisfied for the audio block reproduced by the audio reproducing unit and the audio reproduction unit (S51) for reproducing from the recording medium based on Means (S93) are provided.

  The first time axis defines the image / sound recording time, and the second time axis defines the image / sound creation time. First image time information along the first time axis and second image time information along the second time axis are assigned to each of the plurality of image frames recorded on the recording medium by the first recording means. Also, first audio time information along the first time axis and second audio time information along the second time axis are assigned to each of the plurality of audio blocks recorded on the recording medium by the second recording means.

  The first specifying means specifies, from among the plurality of audio blocks, an audio block to which the first audio time information that satisfies the time condition is satisfied with the first image time information assigned to the reference image frame. The second specifying means specifies the audio block to which the second audio time information satisfying the time condition is satisfied with the second image time information assigned to the reference image frame, and the audio block specified by the first specifying means Specify from the following audio blocks.

  The image reproducing means reproduces a plurality of image frames delayed from the reference image frame from the recording medium based on the second image time information. The audio reproduction means reproduces a plurality of audio blocks related to the plurality of image frames reproduced by the image reproduction means from the recording medium based on the second audio time information. The reference image frame is redetermined by the redetermining means when an error condition regarding continuity of creation time is satisfied for the audio block reproduced by the audio reproducing means.

  Thus, the image reproduction process and the audio reproduction process are executed based on the time information along the second time axis. Therefore, synchronization can be accurately established between the image and the sound. When the error condition regarding the continuity of the creation time is satisfied for the audio block, the reference image frame is re-determined, and the image reproduction process and the audio reproduction process are restarted based on the time information along the first time axis. As a result, when the error condition is satisfied, the synchronized reproduction from the re-determined reference image frame can be resumed promptly, and the operability is improved.

  A recording / reproducing apparatus according to a second aspect of the invention is dependent on the first aspect, and the re-determination means determines the next image frame of the image frame reproduced this time by the image reproduction means as a reference image frame. When the error condition is satisfied, the reproduced image frame is updated to the next image frame.

  The recording / reproducing apparatus according to the invention of claim 3 is dependent on claim 1 or 2, and further comprises capturing means (30) for capturing an image frame and an audio block through a public network. The difference between the time along the first time axis and the time along the second time axis is likely to be manifested when communication is performed via the public line network. In such a case, the significance of focusing on both the first time axis and the second time axis increases.

  A recording / reproducing apparatus according to a fourth aspect of the invention is dependent on any one of the first to third aspects, wherein the time condition is a condition that the earliest time lags behind the time indicated by the noticed image time information.

  A recording / reproducing apparatus according to a fifth aspect of the invention is dependent on any one of the first to fourth aspects, and further comprises start image reproducing means (S23) for reproducing the reference image frame from the recording medium.

  The recording / reproducing apparatus according to the invention of claim 6 is dependent on any one of claims 1 to 5, wherein the error condition is a time indicated by the second image time information assigned to the image frame reproduced this time by the image reproducing means. A first threshold condition is included in which the absolute value of the difference from the time indicated by the second audio time information assigned to the audio block to be reproduced next time by the audio reproducing means exceeds the first threshold. When the second time axis transitions between normal time and summer time, and the time indicated by the second image time information corresponds to normal time, while the second audio time information corresponds to summer time, the first threshold condition Is satisfied. As a result, durability against distortion on the second time axis is improved.

  A recording / reproducing apparatus according to a seventh aspect of the present invention is dependent on the sixth aspect, and the first threshold corresponds to a period of sound expressed by one sound block.

  The recording / reproducing apparatus according to an eighth aspect of the invention is dependent on any one of the first to seventh aspects, wherein the error condition is a current image frame reproduced this time by the image reproducing means and a next image frame reproduced next time by the image reproducing means. Including a block condition that an audio block to be reproduced is missing.

  The recording / reproducing apparatus according to the invention of claim 9 is dependent on any one of claims 6 to 8, and the error condition is the time indicated by the second image time information assigned to the image frame reproduced this time by the image reproducing means. It further includes a second threshold condition that the absolute value of the difference from the time indicated by the second image time information assigned to the image frame to be reproduced next time by the image reproducing means exceeds the second threshold.

  A recording / reproducing apparatus according to a tenth aspect of the present invention is dependent on any one of the first to ninth aspects, and the first time axis corresponds to a time axis of world standard time.

  The recording / reproducing program according to the invention of claim 11 creates the first image time information and the image / sound along the first time axis defining the image / sound recording time in the processor (44) of the recording / reproducing apparatus (200). A first recording step (S5) for recording, on the recording medium (52), a plurality of image frames each assigned with second image time information along a second time axis defining time; A second recording step (S11) for recording a plurality of audio blocks each of which is assigned one audio time information and second audio time information along the second time axis on a recording medium; A first identification step (S33, S35) for identifying an audio block assigned with first audio time information satisfying a time condition with image time information from a plurality of audio blocks, assigned to a reference image frame Second image time information and A second specifying step (S39, S41, S43) for specifying a voice block to which the second voice time information satisfying the time condition is assigned among the voice blocks after the voice block specified by the first specifying step; An image reproduction step (S61) for reproducing a plurality of image frames delayed from the reference image frame from the recording medium based on the second image time information, and a plurality of audio blocks related to the plurality of image frames reproduced by the image reproduction step 2 When the audio playback step (S51) for reproducing from the recording medium based on the audio time information and the error condition relating to the continuity of the creation / recording time for the audio block reproduced by the audio reproduction step are satisfied, the reference image frame is replayed. It is a recording / reproducing program for executing a redetermination step (S93) to be determined.

  As in the first aspect of the invention, establishment of accurate synchronization between the image and the sound and improvement in operability are achieved.

  The recording / reproducing method according to the invention of claim 12 is a recording / reproducing method executed by the recording / reproducing apparatus (200), wherein the first image time information and the image along the first time axis defining the recording time of the image / sound. First recording step (S5) for recording a plurality of image frames each assigned with second image time information along a second time axis that defines the audio creation time on the recording medium (52), first time A second recording step (S11) for recording on the recording medium a plurality of audio blocks each assigned with the first audio time information along the axis and the second audio time information along the second time axis, assigned to the reference image frame A first specifying step (S33, S35) for specifying, from among a plurality of audio blocks, an audio block to which the first audio time information that satisfies the time condition is satisfied with the first image time information, a reference image frame Assigned to the second A second specifying step (S39) for specifying a voice block to which the second voice time information satisfying the time condition with the two image time information is assigned from the voice blocks after the voice block specified by the first specifying step (S39). , S41, S43), an image reproduction step (S61) for reproducing a plurality of image frames delayed from the reference image frame from the recording medium based on the second image time information, and related to the plurality of image frames reproduced by the image reproduction step An audio reproduction step (S51) for reproducing a plurality of audio blocks from the recording medium based on the second audio time information, and an error condition relating to continuity of creation / recording time for the audio blocks reproduced by the audio reproduction step are satisfied A redetermining step (S93) for redetermining the reference image frame.

  As in the first aspect of the invention, establishment of accurate synchronization between the image and the sound and improvement in operability are achieved.

  According to this invention, the image reproduction process and the audio reproduction process are executed based on the time information along the second time axis. Therefore, synchronization can be accurately established between the image and the sound. When the error condition regarding the continuity of the creation / recording time is satisfied for the audio block, the reference image frame is re-determined, and the image reproduction process and the audio reproduction process are restarted based on the time information along the first time axis. The As a result, when the error condition is satisfied, the synchronized reproduction from the re-determined reference image frame can be resumed promptly, and the operability is improved.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  With reference to FIG. 1, the surveillance camera system of this embodiment includes a surveillance camera 100 and a recording / reproducing apparatus 200 connected to each other via an internet network 300. The monitoring camera 100 is configured as shown in FIG. 2, and the recording / reproducing apparatus 200 is configured as shown in FIG.

  Referring to FIG. 2, surveillance camera 100 includes an image sensor 10 that captures an object scene. The image sensor 10 periodically outputs image data representing the object scene, and the camera processing circuit 12 performs JPEG compression on each of a plurality of frames of image data output from the image sensor 10. Here, the output cycle of the image data can be adjusted between 1/30 seconds and 1 hour. That is, the frame rate of the image sensor 10 is adjusted between 30 frames / second and 1 frame / 1 hour.

  The compressed image data generated by JPEG compression, that is, JPEG data is written into the SDRAM 20 by the memory control circuit 18. A header and footer to be added to the beginning and end of JPEG data are created by the CPU 24.

  The CPU 24 describes the resolution and frame rate of the image sensor 10, the frame number of the target JPEG data in the header, and describes the time when the target JPEG data was created, that is, the image creation time, in the footer. Here, the image creation time is detected to the millisecond unit by the clock circuit 26 and described in the footer to the millisecond unit. In this way, a JPEG file having the structure shown in FIG.

  Surveillance camera 100 also includes a microphone 14 that captures external audio around the object scene. The sound processing circuit 16 divides the sound data output from the microphone 14 in units of 246 milliseconds, and writes the divided sound data of each block to the SDRAM 20 through the memory control circuit 18. The CPU 24 also creates a header to be added to the head of the audio data of each block.

  The CPU 24 describes the block number of the audio data of interest and the time when the audio data of interest was created, that is, the audio creation time in the header. The voice creation time is also detected by the clock circuit 26 to the millisecond unit and described in the header to the millisecond unit. The header is expressed by 20 bytes, and the audio data of each block is expressed by 5900 bytes. In this way, an audio block having the structure shown in FIG.

  Here, the surveillance camera 100 is installed, for example, in the United States of America, and the time axis adopted by the clock circuit 26 changes between normal time and daylight saving time as shown in FIG. Daylight saving time begins at 2:00 am on the first Sunday in April and ends at 2:00 am on the last Sunday in October. On the start date, 2:00 am becomes 3:00 am, and on the end date, 2:00 am becomes 1:00 am.

  The I / F circuit 22 sends the JPEG file and audio block stored in the SDRAM 20 to the recording / reproducing apparatus 200 through the Internet network 300. As shown in FIG. 4A, the JPEG file is transmitted at a period corresponding to the frame rate of the image sensor 10, and the audio block is transmitted every 246 milliseconds. The JPEG file is transferred according to the TCP / IP protocol, and the audio block is transferred according to the UDP protocol.

  The voice processing circuit 16 is turned on / off by a switching operation. In the on state, the voice block is created as described above and transmitted from the I / F circuit 22, while in the off state, the voice block creation / transmission process is interrupted.

  Referring to FIG. 3, recording / reproducing apparatus 200 includes an I / F circuit 30 connected to the Internet network 300. The JPEG file and the audio block transmitted from the monitoring camera 100 are received by the I / F circuit 30 when the recording mode is selected by the keyboard 54. The received JPEG file and audio block are written into the DRAM 34 via the memory control circuit 32.

  Due to the nature of the transfer process via the Internet network 300, the cycle of receiving a JPEG file does not necessarily match the transmission cycle of the JPEG file from the monitoring camera 100, and the cycle of receiving an audio block is also an audio block from the monitoring camera 100. Does not necessarily coincide with the transmission cycle. For this reason, the JPEG file and the audio block are received with jitter as shown in FIG. 4B, for example. This embodiment is based on the premise that the JPEG file is received by the I / F circuit 30 in the same order as the transmission order, and the audio block is also received by the I / F circuit 30 in the same order as the transmission order.

  The JPEG file stored in the DRAM 34 is then read out by the HDD 50 that has received an image recording command from the CPU 44 and stored in the hard disk 52. The JPEG file is stored in the moving image file shown in FIG. The audio block stored in the DRAM 34 is also read out by the HDD 50 that receives the audio recording command from the CPU 44 and stored in the hard disk 52. The audio blocks are stored in the audio file shown in FIG. 6B in the same order as the reception order.

  The CPU 44 creates the image INDEX table T1 shown in FIG. 7A in parallel with the JPEG file recording process by the HDD 50, and the audio INDEX table shown in FIG. 7B in parallel with the audio block recording process by the HDD 50. Create T2.

  According to FIG. 7A, the image INDEX table T1 is provided with two columns in which frame numbers and image recording times are written, and a plurality of index numbers are assigned to a plurality of sections forming each column. . Further, according to FIG. 7B, the audio INDEX table T2 is provided with two columns in which block numbers and audio recording times are respectively written, and a plurality of index numbers are assigned to a plurality of sections forming each column. Assigned.

  The CPU 44 detects the frame number from the header of the JPEG file subjected to the recording process, detects the time when the recording process is executed, that is, the image recording time from the clock circuit 46 to the millisecond unit, and detects the detected frame number and The image recording times are written in the image INDEX table T1 in the order according to the index number. The clock circuit 46 employs universal standard time (UTC), and the time axis of the clock circuit 46 is common throughout the world. The CPU 44 also detects the block number from the header of the audio block to be recorded, detects the time when the recording process is executed, that is, the audio recording time from the clock circuit 46 to the millisecond unit, and the detected block number. The voice recording times are written in the voice INDEX table T2 in the order according to the index number.

  The image INDEX table T1 and the audio INDEX table T2 are recorded in the hard disk 52 in a file format when the recording mode is ended.

  When the reproduction mode is selected, the moving image file and audio file recorded on the hard disk 52 are reproduced in the following manner. First, the image INDEX table T1 and the sound INDEX table T2 are read from the hard disk 52. Next, the reproduction bar B1 and the slider SL1 shown in FIG. 8 are displayed on the monitor 38 by the image reproduction circuit 36. Near the left end of the reproduction bar B1, numerical values of “month”, “day”, “hour”, “minute”, and “second” among the image creation times described in the first JPEG file of the moving image file are displayed. . In the vicinity of the right end of the playback bar B1, numerical values of “month”, “day”, “hour”, “minute”, and “second” among the image creation times described in the JPEG file at the end of the moving image file are displayed. Is done.

  When the slider SL1 is arranged at a desired position by the mouse pointer 56, the JPEG file corresponding to the position is set as the reference JPEG file, and the acquisition process and the reproduction process of the reference JPEG file are executed. At this time, a file acquisition command is issued from the CPU 44 to the HDD 50, and a file reproduction command is issued from the CPU 44 to each of the JPEG decoder 48 and the image reproduction circuit 36.

  A desired JPEG file stored in the moving image file in the hard disk 52 is acquired by the HDD 50 and written into the DRAM 34 through the memory control circuit 32. The JPEG data stored in the JPEG file is decoded by the JPEG decoder 48, and the image corresponding to the decoded image data is displayed on the monitor 38 by the image reproducing circuit 36 as shown in FIG.

  The image creation time described in the acquired JPEG file is set in each of variable ILTcrnt and variable ILTinit as shown in FIG. Further, the image recording time assigned to the same frame number as that of the acquired JPEG file is detected from the image INDEX table T1. The detected image recording time is set in a variable IUTcrnt as shown in FIG.

  Subsequently, a file acquisition command is issued from the CPU 44 to the HDD 50 in order to acquire the JPEG file next to the JPEG file reproduced this time from the moving image file. The HDD 50 acquires the next JPEG file in the same manner as described above, and writes the acquired JPEG file to the DRAM 34 through the memory control circuit 32. The image creation time described in the acquired JPEG file is set in a variable ILTnxt as shown in FIG.

  That is, the variables ILTcrnt and IUTcrnt indicate the image creation time and the image recording time corresponding to the JPEG file reproduced this time, respectively. The variable ILTinit indicates the image creation time corresponding to the JPEG file that was originally played back when the playback mode was selected. Further, the variable ILTnxt indicates the image creation time corresponding to the JPEG file to be reproduced next time.

  Subsequently, the earliest audio recording time delayed from the image recording time indicated by the variable IUTcrnt is detected from the audio INDEX table T2 as the audio recording time that satisfies the time condition. The detected voice recording time is set in a variable AUTnxt as shown in FIG. Further, a block acquisition command is issued from the CPU 44 to the HDD 50 in order to acquire an audio block corresponding to the variable AUTnxt. A desired audio block stored in the audio file in the hard disk 52 is acquired by the HDD 50 and written into the DRAM 34 through the memory control circuit 32.

  The voice creation time described in the acquired voice block is set in a variable ALTnxt as shown in FIG. Further, it is determined whether or not the image creation time indicated by the variable ILTinit precedes the audio creation time indicated by the variable ALTnxt. If the determination result is negative, the next audio block is acquired from the audio file in the same manner as described above, and the audio creation time described in the acquired audio block is set in the variable ALTnxt.

  That is, the variable ALTnxt is as shown in FIG. 9B until the earliest voice creation time that is later than the image creation time indicated by the variable ILTinit is detected, that is, until the voice creation time that satisfies the time condition is detected. Updated to In relation to the variables ILTinit, ILTcrnt and ILTnxt related to the image creation time, the variable ALTnxt related to the voice creation time is updated as shown in FIG. In this way, the voice block in which the voice creation time that satisfies the time condition is described is specified.

  A plurality of audio blocks after the specified audio block are reproduced every 246 milliseconds with reference to the audio creation time described in each audio block and the system time defined by the clock circuit 44c. At this time, the block reproduction command is repeatedly issued to the audio reproduction circuit 40, and the block acquisition command is repeatedly issued to the HDD 50. Upon receiving the block reproduction command, the audio reproduction circuit 40 reads out the audio block stored in the DRAM 34 through the memory control circuit 32 and outputs the audio corresponding to the read out audio block from the speaker 42. The operation of the HDD 50 that has received the block acquisition command is as described above.

  A plurality of JPEG files after the JPEG file in which the image creation time indicated by the variable ILTinit is described are referred to the frame rate of the monitoring camera 100 with reference to the image creation time and system time described in each JPEG file. It is played at the corresponding period. At this time, a file reproduction command is repeatedly issued to the JPEG decoder 48 and the image reproduction circuit 40, and a file acquisition command is repeatedly issued to the HDD 50. The operations of the JPEG decoder, the image reproduction circuit 40, and the HDD 50 are as described above. As a result, a corresponding image is output from the monitor 38.

  Thus, the audio block is reproduced with reference to the audio creation time instead of the audio recording time, and the JPEG file is reproduced with reference to the image creation time instead of the image recording time. Accordingly, accurate synchronized reproduction is possible regardless of jitter caused by transfer processing via the Internet network 300.

  However, depending on the setting of the monitoring camera 100, transmission of the audio block is interrupted. Further, the time axis adopted by the clock circuit 26 of the monitoring camera 100 may be distorted due to a transition between normal time and daylight saving time, or reset of the clock circuit 26 due to power-off. This distortion destroys the continuity of two audio creation times described in two adjacent audio blocks on the audio file, making it difficult to synchronize and reproduce images and audio.

  Therefore, in this embodiment, as shown in FIG. 11, (1) the absolute value of the difference between the image creation time corresponding to the JPEG file reproduced this time and the audio creation time corresponding to the audio block to be reproduced next is 246. When the time exceeds milliseconds, or (2) there is an audio block recorded between the image creation / recording time corresponding to the JPEG file played this time and the image creation / recording time corresponding to the next JPEG file played back If not, it is determined that the continuity of the voice creation / recording time has been lost, and the reference JPEG file is determined again. The reference JPEG file is a JPEG file received next to the JPEG file reproduced this time. Since the reference JPEG file is re-determined, the synchronized playback of the JPEG file and the audio block is resumed through the processes shown in FIGS. 9A to 9D.

  When the above conditions (1) and (2) are defined as “threshold condition” and “block condition”, respectively, and the upper concept of both is defined as “error condition”, the reference JPEG file is created / recorded for the audio block. It is re-determined when the error condition regarding the continuity of is satisfied. Then, the synchronized reproduction is resumed through reference to the image INDEX table T1 and the audio INDEX table T2. As a result, when the error condition is satisfied, the synchronized playback from the re-determined reference JPEG file can be resumed quickly, and the operability is improved.

  The CPU 44 executes the recording control process shown in FIG. 13 when the recording mode is selected, and executes the reproduction control process shown in FIGS. 14 to 18 when the playback mode is selected. A control program corresponding to these flowcharts is stored in the hard disk 52.

  Referring to FIG. 13, it is determined whether or not a JPEG file has been received in step S1, and whether or not an audio block has been received is determined in step S3. Specifically, whether or not a new JPEG file is secured in the DRAM 34 is determined in step S1, and whether or not a new audio block is secured in the DRAM 34 is determined in step S3. If YES in step S1, the process proceeds to step S5, and if YES in step S3, the process proceeds to step S11.

  In step S5, an image recording command is issued to the HDD 50. The HDD 50 reads the JPEG file stored in the DRAM 34 and writes the read JPEG file to the moving image file in the hard disk 52. In step S7, the current time indicated by the clock circuit 46 is acquired as the image recording time. In step S9, the frame number described in the JPEG file recorded this time and the image recording time acquired in step S7 are written in the image INDEX table T1. When the writing is completed, the process returns to step S1.

  In step S11, an audio recording command is issued to the HDD 50. The HDD 50 reads the audio block stored in the DRAM 34 and writes the read audio block to the audio file in the hard disk 52. In step S13, the current time indicated by the clock circuit 46 is acquired as the voice recording time. In step S15, the block number described in the voice block recorded this time and the voice recording time acquired in step S13 are written in the voice INDEX table T2. When the writing is completed, the process returns to step S1.

  Referring to FIG. 14, in step S21, a file acquisition command is issued to HDD 50 and an image playback command is sent to JPEG decoder 48 and image playback circuit 36 in order to execute acquisition & playback of the designated JPEG file. Issue. A desired JPEG file stored in the moving image file in the hard disk 52 is written into the DRAM 34 through the memory control circuit 32. The JPEG data stored in the JPEG file is decoded by the JPEG decoder 48, and an image corresponding to the decoded image data is displayed on the monitor 38 by the image reproduction circuit 36.

  In step S23, the image creation time is detected from the footer of the JPEG file acquired in step S21, and the detected image creation time is set in a variable ILTcrnt. In step S25, the image recording time assigned to the same frame number as that of the acquired JPEG file is detected from the image INDEX table T1. In step S27, the numerical value indicated by the variable ITLcrnt is set in the variable ITLinit.

  In step S29, a file acquisition command is issued to the HDD 50 in order to acquire the JPEG file next to the JPEG file acquired in step S23. The desired JPEG file is written into the DRAM 34 through the memory control circuit 32 as described above. In step S31, the image creation time is detected from the footer of the acquired JPEG file, and the detected image creation time is set in a variable ILTnxt.

  In step S33, the earliest audio recording time (audio recording time satisfying the time condition) that is delayed from the time indicated by the variable IUTcrnt is detected from the audio INDEX table T2, and the detected audio recording time is set in the variable AUTnxt. In step S35, the audio block recorded at the time indicated by the variable AUTnxt is acquired from the audio file recorded in the hard disk 52, and in step S37, the audio creation time described in the acquired audio block is detected. The detected voice creation time is set in a variable ALTnxt.

  In step S39, it is determined whether or not the time indicated by the variable ILTinit precedes the time indicated by the variable ALTnxt (whether or not the time condition is satisfied). If “NO” here, a block acquisition command is issued to the HDD 50 in a step S41 in order to acquire the next audio block of the audio block acquired in the step S35. The desired audio block is written into the DRAM 34 through the memory control circuit 32 as described above. In step S43, a voice creation time is detected from the acquired voice block, and the detected voice creation time is set in a variable ALTnxt. When the process of step S43 is completed, the process returns to step S39.

  If “YES” in the step S39, the process proceeds to a step S45 to acquire the current system time indicated by the clock circuit 44c as the reproduction start time. The acquired reproduction start time is set in the variable Tinit. In step S47, the current system time is acquired again, and the acquired system time is set in a variable Tcrnt. In step S49, it is determined whether or not “Tcrnt−Tinit”, which is the difference value between the variables Tcrnt and Tinit, exceeds “ALTnxt−ILTinit”, which is the difference value between the variables ALTnxt and ILTinit. If “NO” here, the process directly proceeds to the step S59 while if “YES”, the process proceeds to the step S59 through the processes of the steps S51 to S57.

  In step S51, an audio reproduction command is issued to the audio reproduction circuit 40 in order to reproduce the audio block recorded at the time indicated by the variable ALTnxt. The audio reproduction circuit 40 reads out the audio block stored in the DRAM 34 through the memory control circuit 32, and outputs the audio corresponding to the read audio block from the speaker 42. In step S53, the numerical value indicated by the variable ALTnxt is set in the variable ALTcrnt. In subsequent steps S55 and S57, processing similar to that in steps S41 and S43 described above is executed. Thus, the audio block is continuously reproduced, and the variables ALTcrnt and ALTnxt are updated for each block.

  In step S59, it is determined whether or not “Tcrnt−Tinit”, which is the difference value between the variables Tcrnt and Tinit, exceeds “ILTnxt−ILTinit”, which is the difference value between the variables ILTnxt and ILTinit. If “NO” here, the process directly proceeds to the step S71 while if “YES”, the process proceeds to the step S71 through the processes of the steps S61 to S69.

  In step S61, an image reproduction command is issued to the JPEG decoder 48 and the image reproduction circuit 36 in order to reproduce the JPEG file recorded at the time indicated by the variable ILTnxt. As a result, an image based on the JPEG data stored in the desired JPEG file is displayed on the monitor 38.

  In step S63, the numerical value indicated by the variable ILTcrnt is set in the variable Tlast, and in step S65, the numerical value indicated by the variable ILTnxt is set in the variable ILTcrnt. In subsequent steps S67 and S69, processing similar to that in steps S29 and S31 described above is executed. In this way, the JPEG file is continuously reproduced, and the variables Tlast, ILTcrnt, and ILTnxt are updated for each block.

  In step S71, it is determined whether or not | ILTnxt−ILTcrnt |, which is the absolute difference between the variables ILTnxt and ILTcrnt, exceeds a threshold value TH (= 10 seconds, for example). In step S73, it is determined whether or not the flag FLG2 is “0”. Furthermore, in step S75, whether or not | ILTcrnt−ALTcrnt |, which is the absolute difference between the variable ILTcrnt and the variable ALTnxt, is equal to or less than 246 milliseconds, which is the length of the audio data of one block, that is, the threshold condition is satisfied. It is determined whether or not. Further, in step S77, whether or not there is an audio block recorded in the audio file that is delayed from the time indicated by the variable IUTcrnt and preceded by the time indicated by the variable IUTnxt, that is, whether or not the block condition is satisfied. Is determined.

  If NO in step S71 or S73, the process directly proceeds to step S83. If YES in steps S71, S73, S75, and S77, the flags FLG1 and FLG2 are set to “0” and “1”, respectively, in step S79, and then the process proceeds to step S83. If YES in steps S71 and S73, but NO in step S75 or S77, each of flags FLG1 and FLG2 is set to “1” in step S81, and then the process proceeds to step S83.

  In step S83, it is determined whether or not “Tcrnt−Tlast”, which is a difference value between the variables Tcrnt and Tlast, exceeds a threshold value TH. In step S85, it is determined whether or not the flag FLG2 is “1”. In step S87, it is determined whether or not the flag FLG1 is “1”. If NO in step S83 or S85, the process directly returns to step S47. If YES in steps S83 and S85 and NO in step S87, flags FLG1 and FLG2 are initialized (= 0) in step S89, and the process returns to step S47.

  If YES in any of steps S85, S87, and S89, flags FLG1 and FLG2 are initialized in step S91. In step S93, the JPEG file received next to the JPEG file acquired in step S67 is designated, and then the process returns to step S21. Although not shown, flags FLG1 and FLG2 are initialized before the reproduction control process shown in FIGS. 14 to 18 is started.

  As can be seen from the above description, the image creation time and the sound creation time are defined by the time axis adopted by the clock circuit 26 of the monitoring camera 100. The image recording time and the audio recording time are defined by a time axis adopted by the clock circuit 46 of the recording / reproducing apparatus 200. An image creation time and an image recording time are assigned to each of the plurality of JPEG files recorded on the hard disk 52. Further, each of the plurality of sound blocks recorded on the hard disk 52 is assigned a sound creation time and a sound recording time.

  The CPU 44 specifies an audio block to which an audio recording time satisfying the time condition with the image recording time assigned to the reference JPEG file is assigned from a plurality of audio blocks (S33, S35). The CPU 44 also selects an audio block assigned an audio creation time that satisfies the time condition with the image creation time assigned to the reference JPEG file, from among the audio blocks after the audio block identified in the preceding process. Specify (S39, S41, S43).

  A plurality of JPEG files delayed from the reference JPEG file are reproduced from the hard disk 52 with reference to the image creation times assigned to them (S61). A plurality of audio blocks related to a plurality of JPEG files to be reproduced are reproduced from the hard disk 52 with reference to the audio creation times assigned to them (S51). The reference JPEG file is re-determined (93) when the error condition regarding the continuity of the audio creation time is satisfied.

  Thus, the JPEG file and the audio block are reproduced with reference to the image creation time and the audio creation time. Therefore, synchronization can be accurately established between the image and the sound. When the error condition relating to the continuity of the audio creation time is satisfied, the standard JPEG file is re-determined, and the synchronized reproduction is resumed through reference to the image recording time and the audio recording time which are the world standard time. As a result, when the error condition is satisfied, the synchronized playback from the re-determined reference JPEG file can be resumed quickly, and the operability is improved.

  In this embodiment, attention is paid to the image recording time and the voice storage time in the determination processing in step S77, but instead of this, attention may be paid to the image creation time and the voice creation time.

It is a block diagram which shows the structure of one Example of this invention. It is a block diagram which shows an example of a structure of the surveillance camera applied to the FIG. 1 Example. It is a block diagram which shows an example of a structure of the recording / reproducing apparatus applied to FIG. 1 Example. (A) is an illustration figure which shows an example of the transfer process from a surveillance camera, (B) is an illustration figure which shows an example of the reception process of a recording / reproducing apparatus. (A) is an illustrative view showing an example of a structure of a JPEG file, and (B) is an illustrative view showing an example of a structure of an audio block. (A) is an illustrative view showing an example of the structure of an image file containing data of a plurality of JPEG files, and (B) is an illustrative view showing an example of the structure of an audio file containing a plurality of audio blocks. (A) is an illustrative view showing an example of a table stored in an image INDEX file, and (B) is an illustrative view showing an example of a table stored in an audio INDEX file. It is an illustration figure which shows an example of the image displayed on the monitor applied to a recording / reproducing apparatus. (A) is an illustrative view showing an example of the structure of an image file, (B) is an illustrative view showing an example of the structure of an audio file, and (C) shows an example of a table stored in an image INDEX file. It is an illustration figure, (D) is an illustration figure which shows an example of the table stored in the audio | voice INDEX file. FIG. 4 is an illustrative view showing one portion of behavior of the embodiment in FIG. 3; FIG. 10 is an illustrative view showing another portion of the operation of the embodiment in FIG. 3; It is an illustration figure which shows the relationship between normal time and daylight saving time. FIG. 4 is a flowchart showing one portion of behavior of a CPU applied to the embodiment in FIG. 3; FIG. 11 is a flowchart showing another portion of behavior of the CPU applied to the embodiment in FIG. 3; FIG. 10 is a flowchart showing still another portion of behavior of the CPU applied to the embodiment in FIG. 3; FIG. 10 is a flowchart showing yet another portion of behavior of the CPU applied to the embodiment in FIG. 3; FIG. 11 is a flowchart showing another portion of behavior of the CPU applied to the embodiment in FIG. 3; FIG. 10 is a flowchart showing still another portion of behavior of the CPU applied to the embodiment in FIG. 3;

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Surveillance camera 200 ... Recording / reproducing apparatus 300 ... Internet network 10 ... Image sensor 14 ... Microphone 26, 46 ... Clock circuit 22, 30 ... I / F circuit 44 ... CPU
52 ... Hard disk 56 ... Mouse pointer 38 ... Monitor 42 ... Speaker

Claims (12)

A plurality of first image time information along a first time axis that defines an image / sound recording time and second image time information along a second time axis that defines an image / sound creation time First recording means for recording an image frame on a recording medium;
Second recording means for recording, on the recording medium, a plurality of audio blocks each of which is assigned first audio time information along the first time axis and second audio time information along the second time axis;
First specifying means for specifying, from among the plurality of sound blocks, a sound block to which first sound time information that satisfies a time condition is satisfied with the first image time information assigned to the reference image frame;
The audio blocks after the audio block specified by the first specifying means are selected as audio blocks to which the second audio time information satisfying the time condition is satisfied with the second image time information assigned to the reference image frame. A second specifying means for specifying from among the above,
Image reproducing means for reproducing a plurality of image frames delayed from the reference image frame from the recording medium based on the second image time information;
Audio reproducing means for reproducing a plurality of audio blocks related to a plurality of image frames reproduced by the image reproducing means from the recording medium based on the second audio time information; and an audio block reproduced by the audio reproducing means A recording / reproducing apparatus comprising re-determination means for re-determining the reference image frame when an error condition regarding continuity of creation / recording time is satisfied.   The recording / reproducing apparatus according to claim 1, wherein the re-determination unit determines the next image frame of the image frame reproduced this time by the image reproduction unit as the reference image frame.   The recording / reproducing apparatus according to claim 1, further comprising capturing means for capturing the image frame and the audio block through a public network.   4. The recording / reproducing apparatus according to claim 1, wherein the time condition is a condition indicating an earliest time delayed from a time indicated by noticed image time information.   5. The recording / reproducing apparatus according to claim 1, further comprising start image reproducing means for reproducing the reference image frame from the recording medium.   The error condition includes the time indicated by the second image time information assigned to the image frame reproduced this time by the image reproduction means and the second audio time information assigned to the audio block to be reproduced next time by the audio reproduction means. 6. The recording / reproducing apparatus according to claim 1, further comprising a first threshold value condition that an absolute value of a difference from the indicated time exceeds a first threshold value.   The recording / reproducing apparatus according to claim 6, wherein the first threshold corresponds to a period of audio expressed by one audio block.   The error condition includes a block condition that an audio block to be reproduced is missing between a current image frame reproduced this time by the image reproduction unit and a next image frame reproduced next time by the image reproduction unit, The recording / reproducing apparatus according to claim 1.   The error condition includes the time indicated by the second image time information assigned to the image frame reproduced this time by the image reproduction means and the second image time information assigned to the image frame reproduced next time by the image reproduction means. The recording / reproducing apparatus according to claim 6, further comprising a second threshold condition that an absolute value of a difference from the indicated time exceeds a second threshold.   The recording / reproducing apparatus according to claim 1, wherein the first time axis corresponds to a time axis of world standard time. In the processor of the recording and playback device,
A plurality of first image time information along a first time axis that defines an image / sound recording time and second image time information along a second time axis that defines an image / sound creation time A first recording step of recording an image frame on a recording medium;
A second recording step of recording, on the recording medium, a plurality of audio blocks each of which is assigned first audio time information along the first time axis and second audio time information along the second time axis;
A first specifying step of specifying, from among the plurality of sound blocks, a sound block to which first sound time information that satisfies a time condition is satisfied with the first image time information assigned to the reference image frame;
The audio blocks subsequent to the audio block specified by the first specifying step are the audio blocks to which the second audio time information satisfying the time condition is satisfied with the second image time information assigned to the reference image frame. A second specifying step of specifying from
An image reproduction step of reproducing a plurality of image frames delayed from the reference image frame from the recording medium based on the second image time information;
An audio reproduction step of reproducing a plurality of audio blocks related to a plurality of image frames reproduced by the image reproduction step from the recording medium based on the second audio time information; and an audio block reproduced by the audio reproduction step A recording / reproducing program for executing a redetermination step for redetermining the reference image frame when an error condition regarding continuity of creation / recording time is satisfied. A recording / reproducing method executed by a recording / reproducing apparatus,
A plurality of first image time information along a first time axis that defines an image / sound recording time and second image time information along a second time axis that defines an image / sound creation time A first recording step of recording an image frame on a recording medium;
A second recording step of recording, on the recording medium, a plurality of audio blocks each of which is assigned first audio time information along the first time axis and second audio time information along the second time axis;
A first specifying step of specifying, from among the plurality of sound blocks, a sound block to which first sound time information that satisfies a time condition is satisfied with the first image time information assigned to the reference image frame;
The audio blocks subsequent to the audio block specified by the first specifying step are the audio blocks to which the second audio time information satisfying the time condition is satisfied with the second image time information assigned to the reference image frame. A second specifying step of specifying from
An image reproduction step of reproducing a plurality of image frames delayed from the reference image frame from the recording medium based on the second image time information;
An audio reproduction step of reproducing a plurality of audio blocks related to a plurality of image frames reproduced by the image reproduction step from the recording medium based on the second audio time information; and an audio block reproduced by the audio reproduction step A recording / reproducing method comprising a redetermination step of redetermining the reference image frame when an error condition relating to continuity of creation / recording time is satisfied.

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