JP2013251644A - Recording device and recording control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording device which, when recording the multiplexed data of coded video and voice data simultaneously in a plurality of recording media, can record to a high quality data file while restraining a circuit scale.SOLUTION: When, while recording multiplexed data in a first recording medium 410, a recording control unit 92 receives an instruction to start recording multiplexed data in a second recording medium 420, it starts control for simultaneous recording of multiplexed data. At this time, the recording control unit 92 starts recording to the second recording medium 420 beginning with a video data group which can be decoded without referring to the previous video data group.

Description

  The present invention relates to a recording apparatus and a recording control method, and more particularly to a recording apparatus and a recording control method for simultaneously recording data on a plurality of recording media.

  In recent years, camera recorders capable of simultaneous recording on a plurality of recording media have been put into practical use. In such a camera recorder, a scene at an arbitrary timing by a photographer's operation is recorded on one recording medium, and a photographed image is continuously recorded on another recording medium as a backup to prevent shooting omission. You can also. In particular, in business use (for example, event shooting), simultaneous recording is an effective function for preventing a scoop scene from being missed at a timing unintended by the photographer.

JP 2010-273327 A

  In a camera recorder capable of simultaneous recording, separately providing an encoder and a multiplexer having the number of channels corresponding to the number of recording media causes an increase in circuit scale, power consumption, and cost. Also, when recording simultaneously, simply starting and stopping the recording on one recording medium will not allow the first few frames to be played back, or unnecessary audio and video before and after the scene cut will tend to be mixed. is there.

  The present invention has been made in view of such circumstances, and its purpose is to suppress the circuit scale when simultaneously recording multiplexed data obtained by multiplexing encoded video data and audio data on a plurality of recording media. However, it is an object of the present invention to provide a technique for recording without impairing the quality of video data and audio data immediately after starting recording and immediately before stopping recording on each recording medium.

  In order to solve the above problems, a recording apparatus according to an aspect of the present invention is generated by a multiplexing unit that divides and multiplexes encoded video data and encoded audio data, and is multiplexed by the multiplexing unit. And a recording control unit that records the multiplexed data on the first recording medium, the second recording medium, or both based on the operation instruction. When receiving a recording start instruction for the multiplexed data to the second recording medium while the multiplexed data is being recorded on the first recording medium, the recording control unit starts the simultaneous recording control of the multiplexed data. Recording on the second recording medium is started with a video data group that can be decoded without referring to the video data group.

  Another embodiment of the present invention is also a recording apparatus. The apparatus includes a multiplexing unit that divides and multiplexes the encoded video data and the encoded audio data, and the multiplexed data generated by multiplexing by the multiplexing unit in accordance with an operation instruction. And a recording control unit for recording on the second recording medium or both. The multiplexing unit multiplexes the encoded audio data with delay with respect to the encoded video data so as to correspond to the decoding timings of the encoded video data and the encoded audio data, and the recording control unit When a recording stop instruction to the first recording medium or the second recording medium is received during simultaneous recording on the first recording medium and the second recording medium, the video data group of multiplexed data recorded at that time and When recording of the corresponding audio data group ends, recording on the recording medium related to the recording stop instruction is stopped, and at that time, the latter half of the audio data group corresponding to the video data group recorded last on the recording medium related to the recording stop instruction In the overlap period in which the first half of the next video data group of the video data group overlaps, the storage of the next video data group to be stored in the overlap period is invalidated.

  Yet another embodiment of the present invention is a recording control method. The method includes a multiplexing step for dividing and multiplexing the encoded video data and the encoded audio data, and the multiplexed data generated by multiplexing the first recording medium and the second recording based on an operation instruction. A recording control step of recording on a medium or both. The recording control step starts simultaneous recording control of multiplexed data when receiving an instruction to start recording multiplexed data onto the second recording medium while recording the multiplexed data on the first recording medium. Recording on the second recording medium is started with a video data group that can be decoded without referring to the video data group.

  Yet another embodiment of the present invention is also a recording control method. The method includes a multiplexing step for dividing and multiplexing the encoded video data and the encoded audio data, and the multiplexed data generated by multiplexing the first recording medium and the second recording based on an operation instruction. A recording control step of recording on a medium or both. The multiplexing step multiplexes the encoded audio data with delay with respect to the encoded video data so as to correspond the decoding timing of the encoded video data and the encoded audio data, and the recording control step When a recording stop instruction to the first recording medium or the second recording medium is received during simultaneous recording on the first recording medium and the second recording medium, the video data group of multiplexed data recorded at that time and When recording of the corresponding audio data group ends, recording on the recording medium related to the recording stop instruction is stopped, and at that time, the latter half of the audio data group corresponding to the video data group recorded last on the recording medium related to the recording stop instruction In the overlap period in which the first half of the next video data group of the video data group overlaps, the storage of the next video data group to be stored in the overlap period is invalidated.

  According to the present invention, when the multiplexed data of encoded video data and audio data is simultaneously recorded on a plurality of recording media, it can be recorded as a high-quality data file while suppressing the circuit scale.

It is a figure which shows the structure of the imaging device which concerns on embodiment of this invention. It is a figure which shows the example of a data structure of the data file produced | generated based on MPEG2-TS. It is a figure which shows the multiplexing example of the data stream produced | generated based on MPEG2-TS. FIG. 4 is a diagram for explaining a case where GOP2 is extracted from the data stream of FIG. 3; FIGS. 5A to 5B are diagrams for explaining the types of GOPs. It is a figure which shows an example of the accumulation | storage data memorize | stored in a multiplexing buffer. It is a figure which shows the example of recording operation of the 1st recording medium and 2nd recording medium in independent recording mode. It is a figure for demonstrating the recording start process to a 2nd recording medium. It is a flowchart for demonstrating the recording start process to a 2nd recording medium. It is a figure for demonstrating the recording stop process to the 2nd recording medium. It is a flowchart for demonstrating the recording stop process to a 2nd recording medium. It is a figure for demonstrating the data preserve | saved at the 1st recording medium and the 2nd recording medium after completion | finish of recording to the 1st recording medium and 2nd recording medium of multiplexed data.

  FIG. 1 is a diagram illustrating a configuration of an imaging apparatus 500 according to an embodiment of the present invention. The imaging device 500 includes an imaging unit 200, an audio acquisition unit 300, a recording device 100, a first recording medium 410, and a second recording medium 420. The imaging apparatus 500 corresponds to, for example, a business camera recorder.

  The imaging unit 200 includes a solid-state imaging device such as a charge coupled device image sensor (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor. The imaging unit 200 performs predetermined signal processing on the signal converted from light to electricity by the solid-state imaging device, and outputs the signal to the recording apparatus 100 as a video signal. The voice acquisition unit 300 includes a microphone. The sound acquisition unit 300 performs predetermined signal processing on a signal converted from sound to electricity by a microphone, and outputs the signal to the recording apparatus 100 as a sound signal.

  The recording apparatus 100 includes a video encoding unit 10, a video buffer 20, an audio encoding unit 30, an audio buffer 40, a multiplexing unit 50, a multiplexing buffer 60, a recording medium interface unit 70, a user interface unit 80, and a control unit 90. Prepare. The video encoding unit 10, the audio encoding unit 30, and the multiplexing unit 50 are configured by dedicated hardware. Each of the video buffer 20, the audio buffer 40, and the multiplexing buffer 60 is constructed by a RAM (Random Access Memory) in a FIFO (first-in first-out) format or a ring buffer format. The control unit 90 is configured by a microcomputer. Note that these configuration methods are examples. For example, at least some of the functions of the video encoding unit 10, the audio encoding unit 30, and the multiplexing unit 50 may be realized by software processing using a microcomputer.

  The video encoding unit 10 encodes the video signal input from the imaging unit 200 in a predetermined format. For example, MPEG-2, MPEG-4 AVC / H. H.264 or the like can be employed. The video encoding unit 10 outputs an encoded video signal (hereinafter referred to as encoded video data) to the video buffer 20. The video buffer 20 temporarily stores the encoded video data input from the video encoding unit 10.

  The voice encoding unit 30 encodes the voice signal input from the voice acquisition unit 300 in a predetermined format. For example, MP3, AAC, AC3, etc. can be adopted as the format. The audio encoding unit 30 outputs an encoded audio signal (hereinafter referred to as encoded audio data) to the audio buffer 40. The audio buffer 40 temporarily stores the encoded audio data input from the audio encoding unit 30.

  The multiplexing unit 50 multiplexes the encoded video data stored in the video buffer 20 and the encoded audio data stored in the audio buffer 40 in a predetermined format. For example, MPEG2-TS (Transport Stream), MPEG2-PS (Program Stream), etc. can be adopted as the format. In these formats, the multiplexing unit 50 divides and multiplexes the encoded video data and the encoded audio data, which are element streams, into respective packets.

  In addition, the multiplexing unit 50 multiplexes the encoded audio data with a delay with respect to the encoded video data in order to correspond the decoding timings of the encoded video data and the encoded audio data. In general, decoding of encoded video data takes longer than decoding of encoded audio data. Therefore, by shifting the multiplexing position of the encoded audio data backward, the decoding completion times of both scenes are easily matched.

  The multiplexing unit 50 outputs the generated multiplexed data to the multiplexing buffer 60. The multiplexing buffer 60 temporarily stores the multiplexed data generated by the multiplexing unit 50.

  The recording medium interface unit 70 is an interface for recording the multiplexed data stored in the multiplexing buffer 60 on the first recording medium 410 or the second recording medium 420. The first recording medium 410 and the second recording medium 420 are randomly accessible recording media such as a semiconductor memory card, an optical disk, and a hard disk. For example, the first recording medium 410 and the second recording medium 420 may be two semiconductor memory cards respectively mounted in two slots.

  The recording apparatus 100 includes a mode (hereinafter referred to as a normal recording mode) in which multiplexed data stored in the multiplexing buffer 60 is sequentially recorded in series on the first recording medium 410 and the second recording medium 420, and There are two types of recording modes: a mode in which recording is started by controlling the start / stop of recording on the first recording medium 410 and the second recording medium 420 (hereinafter referred to as an independent recording mode). In the normal recording mode, since the other recording medium can be replaced during recording on one recording medium, continuous recording for a long time is possible. In the independent recording mode, simultaneous recording described later is possible.

  The user interface unit 80 receives an operation instruction from the user and displays a captured video, a menu screen, a status, and the like. The user interface unit 80 can be realized using a known device such as a button, a monitor, or a touch panel. For example, the user interface unit 80 receives an operation instruction for mode selection from the user. When receiving an operation instruction, the user interface unit 80 notifies the control unit 90 of the operation instruction.

  In the present embodiment, the user interface unit 80 includes a first recording operation unit 81 and a second recording operation unit 82. The first recording operation unit 81 is a recording start / stop button used mainly by the user. The first recording operation unit 81 is used to start / stop recording on the first recording medium 410 in both the normal recording mode and the independent recording mode. The second recording operation unit 82 is a recording start / stop button used by the user as a sub. The second recording operation unit 82 is used to start / stop recording on the second recording medium 420 in the independent recording mode. When receiving a recording start / stop operation instruction from the user, the first recording operation unit 81 and the second recording operation unit 82 notify the control unit 90 of the operation instruction.

  Instead of using the first recording operation unit 81 as a main button and the second recording operation unit 82 as a sub button, the first recording operation unit 81 is used as a dedicated button for starting / stopping recording on the first recording medium 410. The recording operation unit 82 may be a dedicated button for starting / stopping recording on the second recording medium 420.

  The control unit 90 comprehensively controls each component of the recording apparatus 100. In this embodiment, an operation instruction and an operation timing are given to the video encoding unit 10, the audio encoding unit 30, the multiplexing unit 50, and the recording medium interface unit 70. In the present embodiment, other functions of the control unit 90 will be described in order to focus on recording control of the multiplexed data stored in the multiplexing buffer 60 on the first recording medium 410 and / or the second recording medium 420. Is omitted.

  The control unit 90 includes a recording operation receiving unit 91 and a recording control unit 92. The recording operation accepting unit 91 accepts a recording start / stop operation instruction from the first recording operation unit 81 or the second recording operation unit 82. The recording operation reception unit 91 notifies the recording control unit 92 of a recording start / stop instruction to the first recording medium 410 or the second recording medium 420 according to the received operation instruction.

  The recording control unit 92 records the multiplexed data stored in the multiplexing buffer 60 on the first recording medium 410, the second recording medium 420, or both based on an instruction from the recording operation receiving unit 91. When recording on both (ie, simultaneously recording), the recording control unit 92 records the multiplexed data stored in the multiplexing buffer 60 on the first recording medium 410 and the second recording medium 420 in a time division manner. .

  FIG. 2 is a diagram showing an example of the data structure of a data file generated in conformity with MPEG2-TS. Hereinafter, an example in which the multiplexing unit 50 generates a multiplexed stream compliant with MPEG2-TS will be described. In MPEG2-TS, video data and audio data are each divided in units of a maximum of 184 bytes. A TS header is added to each divided data, and a 188-byte TS packet is generated. Note that there are also packets configured in units of 192 bytes by adding 4-byte ATS (Arrival Time Stamp) information to the head of the TS packet. Each TS header includes 13-bit information called a packet identifier (PID).

  The MPEG2-TS stream shown in FIG. 2 includes a PAT (Program Association Table) packet, a PMT (Program Map Table) packet, a SIT (Selection Information Table) packet, a PCR (Program Clock Reference) packet, a NULL packet, a Video packet, and an Audio. Contains packets. In FIG. 2, the video packet is simply expressed as “V”, and the audio packet is simply expressed as “A”.

  The PAT packet is a packet in which a list of programs (contents) including video / audio included in the MPEG2-TS stream is stored as a list of PIDs indicating PMT packets corresponding to the respective programs. The PMT packet is a packet storing each PID indicating a Video packet / Audio packet for storing data such as video / audio included in one corresponding program. The SIT packet is a packet that stores information related to a program included in the partial transport stream. The PCR packet is a packet including a reference clock used for synchronization. In MPEG2-TS, it is recommended that PCR packets be inserted at 100 ms intervals. A NULL packet is a dummy packet that does not contain data. It is used for bit rate adjustment and unnecessary data masking described later. The reproduction side can accurately reproduce the designated program by referring to the management packet such as the PAT packet, the PMT packet, the SIT packet, and the PCR packet.

  FIG. 3 is a diagram illustrating an example of multiplexing data streams generated in conformity with MPEG2-TS. In FIG. 3, a blank box indicates a Video packet, and a hatched box indicates an Audio packet. Note that management packets such as PAT packets are omitted. In the MPEG series compression encoding method, video data is generally encoded in GOP (Group Of Pictures) units including a plurality of pictures. GOPn (Audio) indicates an audio data group corresponding to a GOPn (Video) scene. As described above, in order to match the decoding timing on the decoding side, the encoded audio data is delayed and multiplexed with the encoded video data. That is, the multiplexed position of the encoded audio data is shifted backward with respect to the encoded video data.

  FIG. 4 is a diagram for explaining a case where GOP2 is extracted from the data stream of FIG. If video data and audio data for a necessary time axis are extracted as they are from the multiplexed data stream stored in the multiplexing buffer 60, extra data is mixed in or necessary data is missing. When data from the head of GOP2 (Video) to the tail of GOP2 (Audio) is extracted from the data stream, partial data behind GOP1 (Audio) and partial data ahead of GOP3 (Video) are mixed. End up. When data from the beginning of GOP2 (Video) to the tail of GOP2 (Video) is extracted, partial data behind GOP1 (Audio) is mixed and partial data behind GOP2 (Audio) is lost. This solution will be described later.

  FIGS. 5A to 5B are diagrams for explaining the types of GOPs. FIG. 5A shows an example of an OpenGOP, and FIG. 5B shows an example of a Closed GOP. In the MPEG series, three types of pictures are used: an I picture, a P picture, and a B picture. An I picture is a picture that can be decoded independently without referring to other pictures. Encoded using intra-picture prediction. A P picture is a picture that is encoded using only forward prediction. Encoding is performed using inter-picture prediction using a single past picture as a reference picture. A B picture is a picture that is encoded using bi-directional prediction. Encoding is performed using inter-picture prediction using two past and future pictures as reference pictures. H. In H.264 / AVC, two past pictures or two future pictures can be used as reference pictures.

  In general, the I picture has the largest amount of data, the P picture has the next largest amount of data, and the B picture has the smallest amount of data. Therefore, the compression efficiency improves as the number of B pictures increases. However, since the number of I pictures is reduced, the playback start point is reduced.

  The GOP shown in FIG. 5A includes six pictures in the order of B picture, B picture, I picture, B picture, B picture, and P picture. The first two B pictures of this GOP need to refer to the last P picture of the previous GOP of the GOP. A GOP including a B picture that needs to refer to a picture included in the previous GOP is referred to as an OpenGOP. When the head of the multiplexed stream is OpenGOP, the two B pictures at the head cannot be decoded, so that a frame drop occurs during reproduction.

  The GOP shown in FIG. 5B has the same picture arrangement as that in FIG. 5A, but the first two B pictures refer only to the subsequent I picture. A GOP that does not include a picture that refers to a picture of the previous GOP is called a Closed GOP. When the head of the multiplexed stream is a Closed GOP, a frame drop at the head does not occur during playback.

  H. In H.264 / AVC, the reference picture of the P picture is not limited to the immediately preceding I picture or P picture. Also, the reference picture in the past direction of the B picture is not limited to the immediately preceding I picture or P picture. H. In H.264 / AVC, a P picture or a B picture may straddle an I picture in the past direction and refer to a past picture from the I picture. That is, the I picture may not be an anchor. So H. In H.264 / AVC, an I picture serving as an anchor is designated as an IDR picture. H. In H.264 / AVC, a GOP starting from an IDR picture is a Closed GOP.

  The video encoding unit 10 periodically or regularly sets the picture type designation and GOP boundary for each frame or slice. Alternatively, they are adaptively changed according to the processing load, data amount, or external command.

  FIG. 6 is a diagram illustrating an example of accumulated data stored in the multiplexing buffer 60. The multiplexing buffer 60 shown in FIG. 6 is composed of a ring buffer capable of storing a certain number of GOPs. In FIG. 6, seven GOPs (GOPm + 1 to GOPm + 7) are stored in the multiplexing buffer 60. Free space still exists. When there is no free space, the newly input GOP is overwritten from the first input GOP (GOPm + 1 in FIG. 6). Thus, each GOP constituting the multiplexed stream is stored in the multiplexing buffer 60 for a finite time.

  In FIG. 6, a GOP including a horizontal block indicates a Closed GOP. That is, GOPm + 1, GOPm + 3, GOPm + 5, and GOPm + 7 are Closed GOPs, and GOPm + 2, GOPm + 4, and GOPm + 6 are OpenGOPs. As described above, the multiplexed stream temporarily stored in the multiplexing buffer 60 shown in FIG. 6 is a stream in which one closed GOP is periodically inserted into two GOPs. This period is an example, and for example, a stream in which one Closed GOP is inserted into four GOPs may be used.

  FIG. 7 is a diagram illustrating a recording operation example of the first recording medium 410 and the second recording medium 420 in the independent recording mode. In this recording operation example, when recording on the first recording medium 410 and the second recording medium 420 is stopped, the recording control unit 92 issues a recording start instruction to the first recording medium 410 temporarily stored in the multiplexing buffer 60. Accept. When receiving the instruction, the recording control unit 92 opens the data file 1 and starts recording the multiplexed data on the first recording medium 410.

  Thereafter, the recording control unit 92 receives an instruction to start recording the multiplexed data on the second recording medium 420. When receiving the instruction, the recording control unit 92 opens the data file 2 and starts recording the multiplexed data on the second recording medium 420. At this point, a simultaneous recording state on the first recording medium 410 and the second recording medium 420 is entered. Thereafter, the recording control unit 92 receives an instruction to stop recording the multiplexed data on the second recording medium 420. When the instruction is accepted, recording of the multiplexed data on the second recording medium 420 is stopped, and the data file 2 is closed. At this point, the simultaneous recording state ends.

  Thereafter, the recording control unit 92 receives an instruction to stop recording the multiplexed data on the first recording medium 410. When the instruction is accepted, recording of the multiplexed data on the first recording medium 410 is stopped, and the data file 1 is closed. Such a recording operation is used when recording a video of a desired scene on the second recording medium 420 while backing up all of the video being shot on the first recording medium 410.

  Hereinafter, the processing of the recording control unit 92 at the start of recording on the second recording medium 420 illustrated in FIG. 7 will be described. When the recording control unit 92 receives an instruction to start recording the multiplexed data on the second recording medium 420 while recording the multiplexed data stored in the multiplexing buffer 60 on the first recording medium 410, the recording control unit 92 receives the multiplexing data. Start simultaneous recording control of digitized data. At that time, not the second type video data group that can be decoded without referring to the previous video data group, but the first type video data group that can be decoded without referring to the previous video data group, Recording of the multiplexed data on the second recording medium 420 is started. The first type of video data group corresponds to the above-mentioned Closed GOP, and the second type of video data group corresponds to the above-mentioned Open GOP.

  In order to record the multiplexed stream starting with the first type of video data group on the second recording medium 420, the recording control unit 92 can employ the following three methods. The first method uses the video encoding unit 10 to generate a video data group of multiplexed data to be recorded next in the first type with reference to a time point when a recording start instruction to the second recording medium 420 is received. It is a method of instructing. When this method is adopted, the video encoding unit 10 needs to have a function of specifying an arbitrary picture type in an arbitrary frame in accordance with an external command, but a position close to the timing at which the recording start instruction is received. You can start recording from

  In the second and third methods, it is assumed that the video encoding unit 10 generates encoded video data in which the first type video data group and the second type video group are periodically mixed. In the second method, the video data group of the multiplexed data stored in the multiplexing buffer 60 to be recorded next is the second type to be recorded next with reference to the time point when the recording start instruction to the second recording medium 420 is received. In the case of the video data group, the recording start of the multiplexed data on the second recording medium 420 is suspended until the first type of video data group appears. When this method is employed, the video encoding unit 10 does not need to have the above-described function.

  The third method is to multiplex when the video data group of the multiplexed data to be recorded next is the second type video data group with reference to the time point when the recording start instruction to the second recording medium 420 is received. The recording of the multiplexed data onto the second recording medium 420 is started retroactively to the position where the first type video data group exists among the plurality of video data groups stored in the buffer 60. When this method is employed, it is not necessary for the video encoding unit 10 to have the above-described function, and video data and audio data at a timing when a recording start instruction is accepted can be reliably recorded. In this case, the recording is accompanied by a pre-record function.

  In addition, the recording control unit 92 multiplexes the management information for identifying each packet of multiplexed data to be recorded on the second recording medium 420 after the simultaneous recording control described above is started, on the second recording medium 420. Append to the beginning of digitized data. The management information corresponds to management packets such as the above-described PAT packet, PMT packet, and PCR packet.

  Further, after starting the above-described simultaneous recording control, the recording control unit 92 overlaps the first half of the video data group first recorded on the second recording medium 420 and the second half of the audio data group corresponding to the previous video data group. In the overlap period, the storage of the audio data group to be stored in the overlap period is invalidated. Hereinafter, the recording start process to the second recording medium 420 by the recording control unit 92 will be described in more detail with specific examples.

  FIG. 8 is a diagram for explaining a recording start process on the second recording medium 420. The upper multiplexed stream indicates a stream recorded from the multiplexing buffer 60 to the first recording medium 410. The lower multiplexed stream indicates a stream recorded from the multiplexing buffer 60 to the second recording medium 420. In the figure, a blank box indicates a Video packet, a hatched box indicates an Audio packet, and a black box indicates a packet subjected to Closed GOP processing. The Closed GOP-processed packet is an I picture packet (IDR picture in the case of H.264 / AVC).

  In the example shown in FIG. 8, a recording start instruction to the second recording medium 420 is issued when the multiplexed stream is recorded on the first recording medium 410 to the middle of GOPm + 2. Assuming the state of the multiplexing buffer 60 shown in FIG. 6, since GOPm + 3 next to GOPm + 2 is a Closed GOP, recording from the head of GOPm + 3 onto the second recording medium 420 without changing the picture type of the head picture of GOPm + 3 Can start.

  If the time point when the recording start instruction to the second recording medium 420 is issued is the time point when it is recorded on the first recording medium 410 to the middle of GOPm + 3 of the multiplexed stream, the next GOPm + 4 is OpenGOP. In this case, the recording control unit 92 instructs the video encoding unit 10 to change the next GOPm + 4 to the Closed GOP. If the timing is impossible, the next GOP is instructed to be a Closed GOP. Further, instead of instructing the video encoding unit 10 to change GOPm + 4 to Closed GOP, recording of GOPm + 4 on the second recording medium 420 may be skipped and recording may be started from GOPm + 5 which is a Closed GOP. Further, recording may be started from GOPm + 1 one step back from GOPm + 1 which is a Closed GOP.

  In FIG. 8, a section in which a data section of GOPm + 2 (Audio) and a data section of GOPm + 3 (Video) overlap is an overwriting processing area. The recording control unit 92 overwrites the data for the second recording medium 420 immediately after the data in the overwriting processing area has been recorded on the first recording medium 410. That is, the recording control unit 92 performs time series processing. Specifically, the recording control unit 92 has a PAT packet (indicated as packet “0” in FIG. 8), a PMT packet (indicated as packet “1” in FIG. 8), an SIT packet (in FIG. 7) before the head of GOPm + 3. The packet “2”) and the PCR packet (shown as packet “3” in FIG. 8) are inserted. More precisely, the PAT packet, the PMT packet, the SIT packet, and the PCR packet are overwritten on the corresponding packet of GOPm + 2 immediately before GOPm + 3. Further, the recording control unit 92 rewrites the GOPm + 2 Audio packet into a Null packet (denoted as packet “4” in FIG. 8). If GOPm + 3 is not a ClosedGOP, ClosedGOP processing is performed so that the first picture of GOPm + 3 (Video) becomes an I picture (IDR picture in the case of H.264 / AVC).

  When there is a file size alignment rule, the recording control unit 92 appropriately adjusts the file size by forming a NULL packet. Then, the data from the overwrite processing area to the portion recorded on the first recording medium 410 is recorded on the second recording medium 420 after the data file 2 is opened. Note that when the data file needs to be divided at a certain cycle according to the maximum file size defined by a file system such as FAT32, the second recording medium 420 is also the first recording medium at a timing compliant with the first recording medium 410. File division processing is performed in the same manner as the recording medium 410.

  In FIG. 8, the PAT packet, the PMT packet, and the PCR packet that are periodically inserted in the upper multiplexed stream are omitted.

  FIG. 9 is a flowchart for explaining a recording start process on the second recording medium 420. The recording control unit 92 receives an instruction to start recording the multiplexed stream on the second recording medium 420 during recording of the multiplexed stream on the first recording medium 410 (S10). The recording control unit 92 instructs the video encoding unit 10 to perform the Closed GOP process on the GOP next to the GOP recorded on the first recording medium 410 at that time (S12). The recording control unit 92 starts recording on the second recording medium 420 from the next GOP subjected to the Closed GOP process (S14). At that time, a PAT packet, a PMT packet, an SIT packet, and a PCR packet are added before the GOP to start recording (S16), and the audio packet of the GOP immediately before the GOP to start recording is replaced with a NULL packet. (S18). Thereafter, similarly to the recording on the first recording medium 410, the GOPs stored in the multiplexing buffer 60 are recorded in order.

  Hereinafter, processing of the recording control unit 92 when recording on the second recording medium 420 illustrated in FIG. 7 is stopped will be described. When the recording control unit 92 receives a recording stop instruction to the second recording medium 420 during simultaneous recording of the multiplexed data stored in the multiplexing buffer 60 to the first recording medium 410 and the second recording medium 420, The recording on the second recording medium 420 is stopped when the video data group of the multiplexed data recorded at that time and the recording of the corresponding audio data group are completed. At that time, in the overlap period in which the second half of the audio data group corresponding to the video data group recorded last on the second recording medium 420 overlaps the first half of the next video data group of the video data group, The storage of the next video data group to be stored is invalidated. Hereinafter, the recording stop process to the second recording medium 420 by the recording control unit 92 will be described in more detail with specific examples.

  FIG. 10 is a diagram for explaining a recording stop process for the second recording medium 420. As in FIG. 8, the upper multiplexed stream indicates a stream recorded from the multiplexing buffer 60 to the first recording medium 410. The lower multiplexed stream indicates a stream recorded from the multiplexing buffer 60 to the second recording medium 420.

  In the example shown in FIG. 10, a recording stop instruction to the second recording medium 420 is issued when the multiplexed stream is recorded on the first recording medium 410 and the second recording medium 420 to the middle of GOPk + 2.

  In FIG. 10, a section where a data section of GOPk + 2 (Audio) and a data section of GOPk + 3 (Video) overlap is an overwriting processing area. The recording control unit 92 overwrites the data for the second recording medium 420 immediately after the data in the overwriting processing area has been recorded on the first recording medium 410. That is, the recording control unit 92 performs time series processing. The recording control unit 92 rewrites the GOPk + 2 Video packet into a Null packet (indicated as packet “5”, packet “6”, packet “7”, packet “8”, packet “9” in FIG. 10). Instead of replacing with the Null packet, the recording control unit 92 seeks other packets except the GOPk + 2 Video packet in the overwriting processing area, extracts only the packet, and records it on the second recording medium 420. Also good.

  When there is a file size alignment rule, the recording control unit 92 appropriately adjusts the file size by forming a NULL packet. Then, the data up to the overwrite processing area is recorded on the second recording medium 420, and the data file 2 is closed.

  Note that FIG. 10 is also illustrated by omitting the PAT packet, the PMT packet, and the PCR packet that are periodically inserted into the upper multiplexed stream as in FIG.

  FIG. 11 is a flowchart for explaining a recording stop process for the second recording medium 420. The recording control unit 92 receives an instruction to stop recording the multiplexed stream to the second recording medium 420 during recording of the multiplexed stream to the first recording medium 410 and the second recording medium 420 (S20). The recording control unit 92 replaces the video packet of the GOP next to the GOP to be stopped with a NULL packet (S22). The recording control unit 92 stops recording on the second recording medium 420 when the recording of the GOP Audio packet to be stopped is completed (S24).

  FIG. 12 is a diagram for explaining data stored in the first recording medium 410 and the second recording medium 420 after the multiplexed data has been recorded in the first recording medium 410 and the second recording medium 420. FIG. 12A shows data stored in the first recording medium 410 after the end of recording, and FIG. 12B shows data stored in the second recording medium 420 after the end of recording. As shown in FIG. 12A, the first recording medium 410 stores the data file 1 and its management binary file. The management binary file includes index information of packets included in the data file 1. The index information includes, for example, a packet number, PTS (Presentation Time Stamp), DTS (Decode Time Stamp), and the like. As shown in FIG. 12B, the second recording medium 420 stores the data file 2 and its management binary file.

  After the recording to the second recording medium 420 is stopped, the recording control unit 92 closes the data file 2 and records the management binary file on the second recording medium 420. Similarly, the recording control unit 92 closes the data file 1 after recording to the first recording medium 410 and records the management binary file on the first recording medium 410. The reproduction side can accurately decode and reproduce the data file 1 recorded on the first recording medium 410 by referring to the management binary file. The same applies to the data file 2 recorded on the second recording medium 420.

  As described above, according to the present embodiment, when simultaneously recording multiplexed data obtained by multiplexing encoded video data and audio data on a plurality of recording media, the circuit scale is suppressed and the individual data is suppressed. It is possible to record without impairing the quality of video data and audio data immediately after the start of recording on the recording medium and immediately before the stop. That is, in this embodiment, the video signal and the audio signal are each encoded by a single encoder and then multiplexed by a single multiplexer. The recording control unit records the multiplexed data on a plurality of recording media as different data files in a time division manner. By configuring the encoder and multiplexer with a single channel without using multichannels, it is possible to suppress an increase in circuit scale, power consumption, and cost. In particular, since a camera recorder is required to have portability and low power consumption, there is a strong demand for a single channel design of an encoder and a multiplexer. The recording control unit performs time-division processing, so that recording start / stop of data files on a plurality of recording media can be controlled independently even when a single channel design of an encoder and a multiplexer is adopted. .

  In addition, when recording on another recording medium is started while continuing to record multiplexed data on a certain recording medium, the recording control unit sets the head of the multiplexed data to be recorded on the other recording medium. Let it be ClosedGOP. Thereby, it is possible to prevent at least one B frame from dropping from the top during playback.

  In addition, the recording control unit inserts a management packet at the head of the multiplexed data to be recorded on another recording medium. As a result, it is possible to suppress the inability to reproduce the video data and audio data at the beginning. In general, in MPEG-TS, video data and audio data at the head portion cannot be reproduced unless a PAT packet or PMT packet is added to the head of the data file. This is because it is necessary on the playback side to specify a packet storing video data and audio data to be played back based on PID information stored in the PAT packet and the PMT packet.

  In addition, the recording control unit nullifies the audio packet of the previous GOP in a section where the first half of the video data of the GOP that starts recording on another recording medium overlaps the second half of the audio data of the previous GOP. Replace with a packet. Thereby, it is possible to suppress the reproduction of audio noise that does not match the video at the start of reproduction.

  When stopping the recording of the multiplexed data recorded on another recording medium, the recording control unit overlaps the second half of the audio data of the GOP to be stopped and the first half of the video data of the next GOP. In the interval, the video packet of the next GOP is replaced with a NULL packet. Thereby, it is possible to suppress the reproduction of the image noise that does not match the sound at the end of the reproduction.

  The present invention has been described based on the embodiments. The embodiments are exemplifications, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. .

  In the above-described embodiment, an example in which multiplexed data compliant with MPEG2-TS has been described. The format of this multiplexed data is not limited to MPEG2-TS. For example, multiplexed data may be generated according to MPEG2-PS. Although the size of one packet is larger in MPEG2-PS than in MPEG2-TS, basically the recording control method according to the above-described embodiment can be applied.

  In the above-described embodiment, an example of simultaneous recording on two recording media has been described. However, the number of recording media is not limited to two, and may be three or more. Even in that case, simultaneous recording by the recording control method according to the above-described embodiment is possible.

  In the above-described embodiment, an example in which a recording device capable of simultaneous recording is applied to a camera recorder has been described. However, the present invention is not limited to this. For example, the present invention can be applied to a recording / reproducing apparatus to which video data and audio data are input externally. The recording / reproducing apparatus may include a TV tuner and a function of recording a broadcast TV number. Further, it may be provided with an optical disk drive and a function of reproducing the package content recorded on the optical disk loaded in the optical disk drive. Further, both of the functions may be provided.

  The present invention also includes a program for causing a computer to realize the functions of the recording apparatus described above. These programs may be read from a recording medium and loaded into a computer, or may be transmitted via a communication network and loaded into a computer.

  DESCRIPTION OF SYMBOLS 100 Recording device, 10 Video encoding part, 20 Video buffer, 30 Audio encoding part, 40 Audio buffer, 50 Multiplexing part, 60 Multiplexing buffer, 70 Recording medium interface part, 80 User interface part, 81 1st recording operation Unit, 82 second recording operation unit, 90 control unit, 91 recording operation receiving unit, 92 recording control unit, 200 imaging unit, 300 sound acquisition unit, 410 first recording medium, 420 second recording medium, 500 imaging device.

Claims (9)

A multiplexing unit for dividing and multiplexing each of the encoded video data and the encoded audio data;
A recording control unit that records multiplexed data generated by multiplexing by the multiplexing unit on a first recording medium, a second recording medium, or both based on an operation instruction;
When the recording control unit receives an instruction to start recording the multiplexed data onto the second recording medium while recording the multiplexed data onto the first recording medium, the recording control unit starts simultaneous recording control of the multiplexed data. In this case, the recording apparatus starts recording on the second recording medium starting from a video data group that can be decoded without referring to the previous video data group. The encoded video data includes a first type video data group that can be decoded without referring to the previous video data group, and a second type video data group that is decoded with reference to the previous video data group. And
The recording control unit generates the encoded video data so that the first type of video data group of the multiplexed data to be recorded next is generated on the basis of the time when the recording start instruction is received. The recording apparatus according to claim 1, wherein an instruction is given to a video encoding unit. The encoded video data includes a first type video data group that can be decoded without referring to the previous video data group, and a second type video data group that is decoded with reference to the previous video data group. Mixed,
The recording control unit, when the video data group of the multiplexed data to be recorded next is the second type video data group on the basis of the time point when the recording start instruction is received, The recording apparatus according to claim 1, wherein the start of recording on the second recording medium is suspended until a data group appears. The encoded video data includes a first type video data group that can be decoded without referring to the previous video data group, and a second type video data group that is decoded with reference to the previous video data group. And
The recording control unit, when the video data group of the multiplexed data to be recorded next is the second type video data group on the basis of the time point when the recording start instruction is received, The recording apparatus according to claim 1, wherein recording on the second recording medium is started retroactively to a position where a data group exists. The multiplexing unit divides the encoded video data and the encoded audio data into packets, multiplexes the divided packets,
The recording control unit records management information for identifying each packet of multiplexed data to be recorded on the second recording medium on the second recording medium after starting the simultaneous recording control of the multiplexed data. 5. The recording apparatus according to claim 1, wherein the recording apparatus is added to the head of the power multiplexed data. The multiplexing unit multiplexes the encoded audio data with a delay with respect to the encoded video data so as to correspond to the decoding timing of the encoded video data and the encoded audio data,
The recording control unit overlaps a first half of the first video data group to be recorded on the second recording medium after starting the simultaneous recording control and a second half of the audio data group corresponding to the previous video data group. 6. The recording apparatus according to claim 1, wherein the recording of the audio data group to be stored in the overlapping period is invalidated in the period. A multiplexing unit for dividing and multiplexing each of the encoded video data and the encoded audio data;
A recording control unit that records multiplexed data generated by multiplexing by the multiplexing unit on a first recording medium, a second recording medium, or both based on an operation instruction;
The multiplexing unit multiplexes the encoded audio data with a delay with respect to the encoded video data so as to correspond to the decoding timing of the encoded video data and the encoded audio data,
When the recording control unit receives a recording stop instruction to the first recording medium or the second recording medium during simultaneous recording of the multiplexed data to the first recording medium and the second recording medium, When recording of the video data group of the multiplexed data recorded at the time and the recording of the audio data group corresponding thereto is stopped, recording on the recording medium according to the recording stop instruction is stopped, and at that time, the recording stop instruction In the overlap period in which the second half of the audio data group corresponding to the video data group recorded last on the recording medium and the first half of the next video data group of the video data group overlap, the next to be stored in the overlap period A recording apparatus characterized by invalidating storage of the video data group. A multiplexing step of dividing and multiplexing each of the encoded video data and the encoded audio data;
A recording control step of recording multiplexed data generated by multiplexing on the first recording medium, the second recording medium, or both based on an operation instruction,
The recording control step starts simultaneous recording control of the multiplexed data when receiving an instruction to start recording the multiplexed data onto the second recording medium while recording the multiplexed data on the first recording medium. In this case, the recording control method starts recording on the second recording medium with a video data group that can be decoded without referring to the previous video data group as the head. A multiplexing step of dividing and multiplexing each of the encoded video data and the encoded audio data;
A recording control step of recording multiplexed data generated by multiplexing on the first recording medium, the second recording medium, or both based on an operation instruction,
The multiplexing step multiplexes the encoded audio data with a delay with respect to the encoded video data so as to correspond to the decoding timing of the encoded video data and the encoded audio data,
When the recording control step accepts a recording stop instruction to the first recording medium or the second recording medium during simultaneous recording of the multiplexed data to the first recording medium and the second recording medium, When recording of the video data group of the multiplexed data recorded at the time and the recording of the audio data group corresponding thereto is stopped, recording on the recording medium according to the recording stop instruction is stopped, and at that time, the recording stop instruction In the overlap period in which the second half of the audio data group corresponding to the video data group recorded last on the recording medium and the first half of the next video data group of the video data group overlap, the next to be stored in the overlap period A recording control method characterized by invalidating storage of a video data group.

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