JP6373002B2 - Recording apparatus and control method thereof - Google Patents

Description

  The present invention relates to a recording apparatus and a control method thereof.

  In recent years, NAND flash memory (registered trademark) has become mainstream as a recording medium for digital cameras and digital video cameras. A built-in memory or memory card using a NAND flash memory has a very high transfer rate when the write size is as large as several megabytes (MB) and the write start address matches the block boundary. On the other hand, when the write size to the memory is as small as about 1 sector (512 bytes) unit and the write address is random, the transfer rate is very slow. Also, the transfer rate tends to be fast when the write size to the memory is large, and the transfer rate tends to be slow when it is small. Thus, the transfer rate of a general memory card varies depending on the writing size. In order to record moving image data on a memory card, the transfer rate to the memory card needs to be stable, but depending on the card, the transfer rate may be insufficient and recording may stop.

  Therefore, conventionally, it has been proposed to guarantee the access speed when accessing with a predetermined fixed access size and the writing speed of file system update (see, for example, Patent Document 1).

International Publication No. 05/055064

  However, since only one access size that guarantees the writing speed is defined for each card, there are the following problems. That is, when recording moving image data, since the recording rate to the card and the data rate of the moving image data are different, the moving image data is once stored in the memory, and when the data amount equivalent to the access size is stored, the recording medium Recording to is performed. At this time, the cycle of writing the moving image data to the card differs depending on the data rate of the moving image data.

  For example, when the access size is defined as 4 MB and the data rate of moving image data to be recorded is 10 MB / second (80 Mbps), writing is executed at a cycle of 4 MB / (10 MB / second) = 0.4 seconds. Further, when the data rate of the moving image data is 1 MB / second (8 Mbps), writing is executed at a cycle of 4 seconds.

  However, when a plurality of moving image data having different data rates are simultaneously recorded on one memory card as described above, the writing cycle is different for each data as described above, so that writing control becomes difficult.

  In addition, if a plurality of moving image data having different data rates are not recorded on the memory card at the same timing, the recording time of moving image data does not match when the recording is forcibly terminated, for example, the battery runs out.

  Further, in Patent Document 1, since the recording speed is guaranteed according to the ratio of the free area for each access size in the memory card, in the recording system, the write address to the card becomes discontinuous, and the system side There is also a problem of becoming a load of.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a recording apparatus capable of writing moving image data to a recording medium at an appropriate timing and a control method therefor.

  In order to achieve the above object, the recording apparatus of the present invention includes a processing unit that generates moving image data, a recording unit that writes the moving image data to the recording medium by outputting a write command to the recording medium, A data amount of moving image data written to the recording medium by one write command is set from a plurality of predetermined data amounts, and the moving image data having the set data amount is set on the recording medium by one write command. And a control means for controlling the recording means to write.

  According to the recording apparatus of the present invention, it is possible to provide a recording apparatus capable of writing moving image data to a recording medium at an appropriate timing and a control method therefor.

1 is a block diagram illustrating a functional configuration example of a digital camera as an example of a recording apparatus according to an embodiment. FIG. 1 is a block diagram showing a configuration example of a recording condition setting circuit in FIG. The figure for demonstrating the write-in to a memory card, and the update process of FAT Figure showing the performance definition unit Flow chart showing recording operation The figure which shows the amount of data accumulated in the buffer area when recording moving image data and the state of the write operation The figure which shows the amount of data accumulated in the buffer area when recording moving image data and the state of the write operation Flow chart showing operation in simultaneous recording mode The figure which shows the amount of data accumulated in the buffer area when recording moving image data and the state of the write operation Figure showing the performance definition unit Flow chart showing recording operation The figure which shows the amount of data accumulated in the buffer area when recording moving image data and the state of the write operation

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.
● (first embodiment)
The recording device according to the present invention may be any recording device capable of recording moving image data. Here, a digital video camera 100 as an example will be described with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a functional configuration of a digital video camera 100 according to the present embodiment. A light beam incident on a photographing lens 101 is limited to a predetermined amount by a diaphragm 102, and a subject is placed on an image sensor 103. Form an image. The subject image converted into an analog signal by the image sensor 103 is digitized by the A / D converter 104, subjected to gamma correction, white balance correction, noise reduction processing, and the like by the image processing circuit 105, and then via the data bus 107. And stored in the memory 114. In the present embodiment, the image sensor 103 outputs moving image data of 30 frames per second with one screen (frame) having horizontal 3840 pixels × vertical 2160 pixels. The image size conversion circuit 108 converts the number of pixels of each screen of the moving image data stored in the memory 114 so as to be the number of pixels of the image displayed on the liquid crystal panel 110 or the number of pixels of the recorded moving image. And stored in the memory 114.

  The encoding circuit 109 reads the moving image data for recording stored in the memory 114, The image data is compressed by performing a known encoding process such as H.264 and stored in the memory 114. The liquid crystal panel 110 is a display unit that displays images and various types of information. The liquid crystal driver 111 converts display image data stored in the memory 114 into a liquid crystal display signal and supplies it to the liquid crystal panel 110. Thus, the display image data written in the memory 114 is displayed on the liquid crystal panel 110 via the liquid crystal driver 111.

  Based on an instruction from the control circuit 116, the host controller 112 transmits a command signal to the memory card 113 that is a recording medium, reads out the moving image data stored in the memory 114, and writes it in the memory card 113. In addition, the host controller 112 reads data from the memory card 113 and stores it in the memory 114. The memory card 113 is a memory card composed of a NAND flash memory and a flash controller that can be attached to and detached from the camera body. The moving image data stored in the memory card 113 is managed as a file by the control circuit 116 as management means in accordance with an exFAT (Extended File Allocation Table) file system.

  The memory 114 is constituted by a volatile memory such as a DRAM, temporarily stores the encoded moving image data generated by the encoding circuit 109, and provides a memory space as a buffer for arbitrating with the recording speed of the memory card 113. . The memory 114 also provides a working memory space for the image size conversion circuit 108 for converting the screen size of the captured moving image data, and also provides a space for storing an image displayed on the liquid crystal panel 110 as described above. To do. The operation circuit 115 includes various operation keys for operation by the user, such as a power switch and buttons for instructing start and stop of recording. The operation circuit 115 includes setting keys for various setting items.

  The ROM 117 is an electrically erasable and writable nonvolatile memory, and stores a program that operates on the control circuit (CPU) 116 and the like. The program here is a program for executing various sequences described later in the present embodiment, and realizes each process of the present embodiment described later. The control circuit 116 also performs display control by controlling the liquid crystal driver 111 and the like. The recording condition setting circuit 118 sets various conditions for recording moving image data.

  FIG. 2 is a block diagram illustrating a configuration example of the recording condition setting circuit 118. The recording format setting circuit 201 sets whether to record one moving image or two moving images simultaneously in accordance with an instruction from the control circuit 116 that has received an input from the operation circuit 115. The image size setting circuit 202 receives the input from the operation circuit 115, and in response to an instruction from the control circuit 116, the screen size of the moving image to be recorded (vertical and horizontal pixels per screen of the recorded moving image data). Set. At this time, when two moving images are recorded simultaneously, the screen size for each moving image is set. The data rate setting circuit 203 sets the data rate of the moving image data to be recorded in accordance with an instruction from the control circuit 116 that has received an input from the operation circuit 115. At this time, when recording two moving images simultaneously, the data rate for each moving image is set. The unit size setting circuit 204 sets the unit size used when recording from the set data rate of the moving image data. At this time, when two moving images are recorded simultaneously, a unit size for each moving image is set.

  The file system update setting circuit 205 sets the frequency of file system update according to the data rate and unit size of the set moving image data. At this time, when two moving images are recorded simultaneously, the frequency of file system update for each moving image is set. The buffer area setting circuit 206 sets a necessary area in the memory 114 as a buffer area for storing unrecorded moving image data based on the set unit size. At this time, when two moving images are recorded simultaneously, a buffer area for each moving image is set.

  In FIG. 1 and FIG. 2, the recording condition setting circuit 118 is described as a functional block different from the control circuit 116, but part or all of the functional blocks of the recording condition setting circuit 118 are controlled by the control circuit 116. It may be realized.

  FIG. 3 is a diagram showing video data writing and FAT update processing to the memory card 113. In FIG. 3A, a portion indicated by Data Write is a period during which data is written by one Write command issued from the host controller 112. The amount of data written by one write command is defined as N (MB). The part indicated by FAT Update indicates a period for recording management information for managing data recorded in the memory card 113 as a file in accordance with the description rule of the FAT file system. The contents of FAT Update include file entry write (1 sector) → allocation bitmap write (1 sector) → FAT write (1 sector). As shown in FIG. 3, after writing N (MB) data by one write command, the time required for completing the writing of the management information and completing the file system update is Tuw.

  In this manner, the definition of the access condition to the memory card including the amount of data (unit size) written by one write command and the time Tuw required for writing data and updating the file system is hereinafter referred to as a performance definition unit. . That is, an access condition including a plurality of predetermined data amounts, corresponding write speeds, and write execution times written to the memory card 113 by one write command is defined as a performance definition unit.

  In addition, when data is written according to the access conditions defined by the performance definition unit, the performance of the memory card is guaranteed to be completed within the time indicated by Tuw. Further, the data writing speed according to the access conditions defined in the performance definition unit can be calculated by unit size / Tuw.

  As an example, FIG. 3B and FIG. 3C show examples of performance definition units with a unit size = 4 MB and Tuw = 100 msec. In Media A shown in FIG. 3B and Media B shown in FIG. 3C, the breakdown of the data recording operation time and the file system update operation time is different for the same 100 msec operation period. However, in both cases, a performance of 4 MB / 100 msec = 40 MB / sec is defined. That is, the ratio between the data writing period and the file system update period may be any ratio.

  FIG. 4 is a diagram showing access conditions by four performance definition units defined in the memory card 113 of this embodiment. The access condition by the performance definition unit 1 is unit size = 16 MB, Tuw = 320 msec, and has a performance of 50 MB / sec as a writing speed. The access condition by the performance definition unit 2 is unit size = 8 MB, Tuw = 200 msec, and has a performance of 40 MB / sec as a writing speed. The access conditions by the performance definition unit 3 are unit size = 4 MB, Tuw = 133 msec, and a performance of 30 MB / sec as a writing speed. The access conditions by the performance definition unit 4 are unit size = 2 MB, Tuw = 100 msec, and a performance of 20 MB / sec as a writing speed.

  In the present embodiment, it is assumed that the ROM 117 stores access conditions and write performance information by these four performance definition units. Then, the control circuit 116 reads the access conditions and the write performance by each performance definition unit from the ROM 117. However, the memory card 113 may store information on access conditions and write performance by the performance definition unit. In this case, after the memory card 113 is mounted on the camera, the control circuit 116 reads the access condition and write performance information by the performance definition unit from the memory card 113.

  Next, the operation at the time of moving image recording by the digital camera of this embodiment will be described. In the present embodiment, the user can set the screen size and data rate of moving image data to be recorded on the memory card 113 by operating the operation circuit 115. Further, in the present embodiment, two moving image data can be simultaneously recorded on the memory card 113. The user can set whether to record two moving images simultaneously or to record one moving image. When two moving images are recorded simultaneously, the user can set the screen size and data rate of the moving image data for each moving image.

  In the present embodiment, as the screen size, any one of three modes of horizontal 3840 pixels × vertical 2160 pixels, horizontal 1920 pixels × vertical 1080 pixels, and horizontal 640 pixels × vertical 480 pixels can be set. Further, when recording one moving image, the user can set either 36 MB / second, which is high-quality moving image data, or 18 MB / second, which is standard-definition moving image data, as the data rate of the moving image data. When two moving image data are recorded simultaneously, either 24 MB / second, which is high-quality moving image data, or 12 MB / second, which is standard-definition moving image data, can be set.

  FIG. 5A shows processing executed when the moving image data to be recorded is set by the user as described above. 5A is executed by the control circuit 116 controlling each unit.

  When the user sets the screen size, data rate, and recording format of the moving image to be recorded, the processing in FIG. 5 is started. The control circuit 116 determines whether to record one moving image or two moving images simultaneously according to the set recording format (S501). In the case of setting to record one moving image, the control circuit 116 sets the screen size in the image size setting circuit 202 and sets the data rate of the moving image in the data rate setting circuit 203 based on the user setting (S502). .

  Next, the unit size setting circuit 204 sets the unit size based on the set recording format and moving image data rate (S503). Specifically, a unit size is set by a performance definition unit having a writing speed exceeding the set moving image data rate. For example, when recording of high-quality moving image data is set by the user, the moving image data rate is 36 MB / second. Therefore, a unit size of 8 MB is set by the performance definition unit 2 having a writing speed higher than the performance definition unit shown in FIG.

  Further, the control circuit 116 sets the file system update frequency in the file system update setting circuit 205 (S504). In this embodiment, it is set to be executed every time data of one unit size is written. Next, the buffer area setting circuit 206 sets the size of the buffer area required for recording from the set unit size. Then, an area of the set size is secured in the memory 114 as a buffer memory area for moving image data (S505). For example, when the unit size (Uz) is set to 8 MB, a size larger than 8 MB is secured as the buffer area. Further, the unit size is set as the threshold value T of the data storage amount in the buffer memory area, which is used to determine the write timing for the memory card 113.

  On the other hand, the process when simultaneous recording is set as the recording format will be described later (S506). After the above processing is completed, the recording standby state is entered, and the user is in a state of waiting for an imaging start instruction.

  Next, a process when recording one moving image data will be described. FIG. 5B is a flowchart showing a recording process in the case of setting to record one moving image data as a recording format. FIG. 6 is a diagram showing the moving image data stored in the buffer area, the data written to the memory card 113, and the update operation of the file system after the start of recording. FIG. 6 shows a state in which the performance definition unit 2 in FIG. 4 corresponding to a buffer size of 8 MB is selected.

  In the recording standby state, when the user operates the operation circuit 115 to give an instruction to start recording, the moving image data from the image sensor 103 is processed by the image processing circuit 105 and stored in the frame memory 106. The image size conversion circuit 108 converts the size of each screen of the moving image data stored in the frame memory 106 so as to be the image size set by the image size setting circuit 202 and stores it in the memory 114. The encoding circuit 109 reads and encodes the moving image data stored in the memory 114 and stores it in the buffer area on the memory 114 set by the buffer area setting circuit 206. At this time, the encoding circuit 109 performs encoding so that the data rate of the encoded moving image data does not exceed the upper limit rate determined by the set data rate (S511).

  Next, the control circuit 116 determines whether or not the amount of unrecorded moving image data accumulated in the buffer area has reached the threshold value T (S512). When the data amount of the moving image data accumulated in the buffer area reaches the threshold value T, the control circuit 116 instructs the host controller 112 to write data for the unit size Uz, here, 8 MB. The host controller 112 issues a write command to the memory card 113 and writes moving image data for the unit size from the buffer area on the memory 114 to the memory card (S513). This writing process is shown in the period a in the memory card operation of FIG.

  In the file system update setting circuit 205, an update timing for each unit size Uz is set. Therefore, the control circuit 116 instructs the host controller 112 to update the file system following the writing of data for the unit size (S514). This file system update operation is performed during the period indicated by b in the memory card operation of FIG. The writing of moving image data for one unit size and the updating of the file system are guaranteed by the performance definition unit 2 to be completed within 200 msec. The write performance by the performance definition unit 2 is 40 MB / second. On the other hand, since the data rate of the moving image data is 36 MB / second, in FIG. 6, the amount of data stored in the buffer area decreases at a rate of 4 MB / second during the writing of data to the memory card. When the update of the file system is completed, the control circuit 116 determines whether or not there is an instruction to stop recording (S515). If there is no instruction to stop recording, the process returns to S512.

  Thus, in the writing process to the memory card 113, as shown in FIG. 6, the amount of data stored in the buffer area does not exceed 8 MB, and the buffer does not overflow. Therefore, recording of moving image data does not stop.

  When recording stop is instructed by the user, the control circuit 116 detects this in S515, stops encoding moving image data by the encoding circuit 109, and stops storing encoded data in the buffer area of the memory 114. (S516). Then, the control circuit 116 writes the moving image data remaining in the buffer area of the memory 114 to the host controller 112 (S517), updates the file system (S518), and ends the recording operation. Note that in the writing in S517, since the size of the data written by the write command does not match the unit size, the writing speed may be reduced. However, since the writing operation is performed after the instruction to stop recording, there is no problem even if the writing performance is lowered.

  FIG. 7 is a diagram showing an operation of updating the moving image data stored in the buffer area, the data written in the memory card 113, and the file system when the user sets the data rate of the moving image data to 18 MB / second. When the data rate of moving image data is 18 MB / second, the writing speed is higher than the rate of moving image data regardless of which of the performance definition units 1-4 is selected. Therefore, regardless of which performance definition unit is selected, it is possible to record moving image data continuously. In this embodiment, the performance definition unit 3 whose unit size is half that of the performance definition unit 2 is selected as the performance definition unit.

  Since the unit size of the performance definition unit 3 is 4 MB, a buffer area having a size larger than 4 MB is secured in the memory 114. Further, 4 MB is set as the threshold T. Thereafter, every time the moving image data stored in the buffer area of the memory 114 reaches 4 MB, a write command is issued from the host controller 112. With one write command, moving image data for the unit size Uz, here 4 MB, is written to the memory card 113. This writing process is shown in period c in the memory card operation of FIG. Further, following the writing of the moving image data, the FAT is updated. This writing process is shown in the period d in the memory card operation of FIG. The writing of the video data for one unit size and the file system update are guaranteed to be completed within 133 msec by the performance definition unit 3. The write performance by the performance definition unit 3 is 30 MB / second. On the other hand, since the data rate of the moving image data is 18 MB / second, in FIG. 6, the amount of data stored in the buffer area decreases at a speed of 12 MB / second during the writing of data to the memory card.

  Thus, even when the data rate of the moving image data to be recorded is low, the data amount of the moving image data stored in the buffer area does not exceed 4 MB as shown in FIG. Therefore, recording can be continued without causing a buffer overflow.

  Further, when recording moving image data with standard image quality, access condition 3 is used, which is a unit size that is half the unit size of the performance definition unit selected when recording moving image data with high image quality. Therefore, there is an effect that the moving image data can be written to the memory card at the same interval as the writing interval when recording the high-quality moving image data.

  Next, processing when simultaneous recording is set as the recording format will be described. As described above, the data rate of moving image data recorded in the simultaneous recording mode can be set to either 24 MB / second, which is high-quality moving image data, or 12 MB / second, which is standard-quality moving image data. In the following description, a case where 24 MB / second moving image data and 12 MB / second moving image data are set to be recorded at the same time will be described. 24 MB / second moving image data is the main moving image data, and 12 MB / second moving image data. Will be described as sub video data. FIG. 8 is a flowchart for explaining the processing in the simultaneous recording mode.

  First, the process of S506 in FIG. 5 will be described with reference to FIG. FIG. 8A is a flowchart showing a recording condition setting process when the simultaneous recording mode is set.

  First, the control circuit 116 sets the screen size of two moving image data recorded at the same time in the image size setting circuit 202. Further, the control circuit 116 sets the data rate of two moving image data to be recorded simultaneously in the data rate setting circuit 203. As described above, here, 24 MB / second and 12 MB / second are set as the data rate of the moving image data (S801). Next, the unit size setting circuit 204 selects a performance definition unit used when recording each moving image data based on the values set in the recording format setting circuit 201 and the data rate setting circuit 203, and sets the unit size. Set. In the present embodiment, a performance definition unit used for recording is selected from performance definition units under access conditions that can be written at a higher speed than the sum of the data rates of two moving image data recorded simultaneously.

  In the performance definition unit of FIG. 4, the performance definition unit 1 and the performance definition unit 2 have a writing speed exceeding 36 MB / second, which is the sum of 24 MB / second and 12 MB / second. Therefore, either the performance definition unit 1 or the performance definition unit 2 can be selected to record each moving image data.

  In this embodiment, in order to align the writing timing of each moving picture data to the memory card, the performance definition unit 1 is selected for recording the main moving picture data of 24 MB / second, and the performance for recording the sub moving picture data of 12 MB / second is selected. Select definition unit 2. The unit size (8 MB) of the performance definition unit 2 is half the unit size (16 MB) of the performance definition unit 1. Therefore, as will be described later, it is possible to align the writing timing to the memory card 113.

  Next, the control circuit 116 sets the file system update frequency in the file system update setting circuit 205 (S803). In this embodiment, the performance definition unit is set to be executed each time data is written.

  Next, the buffer area setting circuit 206 is a buffer required for recording each of the two moving image data recorded simultaneously from the values set in the recording format setting circuit 201, the image size setting circuit 202, and the data rate setting circuit 203. Determine the size of the region. Then, the buffer area setting circuit 206 secures a buffer area of the determined size in the memory 114 (S804).

  In the present embodiment, the unit size (Uz1) for recording the main moving image data is set to 16 MB. Therefore, as a buffer area for main moving image data, an area corresponding to the amount of main moving image data accumulated in one writing period of sub moving image data is secured in addition to 16 MB. The writing time of the performance definition unit 2 for recording the sub moving image data is 200 milliseconds (msec), and the data rate of the main moving image data is 24 MB / second. Therefore, the data amount of the main moving image data accumulated for 200 milliseconds is 24 MB / second × 200 milliseconds = 4.8 MB. Therefore, a size larger than 20.8 MB obtained by adding 4.8 MB to 16 MB is secured as a buffer area for main moving image data.

  On the other hand, the unit size (Uz2) for recording the sub moving image data is set to 8 MB. Therefore, in addition to 8 MB, an area corresponding to the amount of sub video data accumulated in one writing period of main video data is secured as a buffer area for sub video data. One writing time of the performance definition unit 1 for recording the main moving image data is 320 milliseconds (msec). Further, the data rate of the sub moving image data is 12 MB / second. Therefore, the data amount of the sub moving image data accumulated in 320 milliseconds is 12 MB / second × 320 milliseconds = 3.84 MB. Therefore, a size larger than 11.84 MB, which is obtained by adding 3.84 MB to 8 MB, is secured as a buffer area for sub moving image data.

  In addition, unit sizes are set as threshold values T1 and T2 for the amount of data stored in the buffer memory area, which are used to determine the timing for writing the main moving picture data and the sub moving picture data stored in the buffer area to the memory card 113. .

  Here, a unit size of 16 MB is set as the threshold value T1 of the main moving image data. Further, the unit size of 8 MB is set as the threshold value T2 of the sub moving image data.

  FIG. 8B is a flowchart showing a recording process in the case where the recording format is set to record two moving image data simultaneously. FIG. 9 is a diagram showing the update operation of the moving image data stored in the buffer area, the data written to the memory card 113, and the file system after the start of recording. FIG. 9 shows a state in which 24 MB / second is set as the main moving image data and 12 MB / second is set as the sub moving image data as described above.

  In the recording standby state, when the user operates the operation circuit 115 to give an instruction to start recording, the moving image data from the image sensor 103 is processed by the image processing circuit 105 and stored in the frame memory 106. The image size conversion circuit 108 converts the size of each screen of the moving image data stored in the frame memory 106 so as to be the image size set by the image size setting circuit 202 and stores it in the memory 114. In the simultaneous recording mode, the image size conversion circuit 108 reads the same moving image data from the memory 114 as two moving image data recorded simultaneously. Then, the image size conversion circuit 108 converts the screen size of each moving image data recorded at the same time into a set screen size and stores it in the memory 114.

  The encoding circuit 109 reads and encodes the moving image data stored in the memory 114 and stores it in the buffer area on the memory 114 set by the buffer area setting circuit 206. At this time, the encoding circuit 109 reads the two moving image data recorded simultaneously, and encodes the encoded moving image data so that the data rate of the encoded moving image data does not exceed the upper limit rate determined by the set data rate. (S811). Also, the encoding circuit 109 stores the encoded main moving image data and sub moving image data in the buffer area reserved for the main moving image and the sub moving image in the memory 114 as described above.

  Next, the control circuit 116 determines whether or not the data amount of the unrecorded main moving image data accumulated in the buffer area has reached the threshold value T1 (S812). When the data amount of the main moving image data accumulated in the buffer area reaches the threshold value T1, the control circuit 116 instructs the host controller 112 to write the data for the unit size Uz1, here 16MB. . The host controller 112 issues a write command to the memory card 113, and writes main moving image data for the specified unit size from the main moving image buffer area on the memory 114 to the memory card (S813). This writing process is shown in the period e in the memory card operation of FIG.

  In the file system update setting circuit 205, an update timing for each unit size Uz1 is set. Therefore, the control circuit 116 instructs the host controller 112 to update the file system following the writing of data for the unit size (S814). This file system update operation is performed during the period indicated by f in the memory card operation of FIG. The writing of the main moving image data for one unit size and the file system update are guaranteed by the performance definition unit 1 to be completed within 320 msec. The write performance by the performance definition unit 1 is 50 MB / second. On the other hand, since the data rate of the main moving image data is 24 MB / second, in FIG. 9, the amount of moving image data stored in the buffer area decreases at a speed of 26 MB / second during the writing of the main moving image data to the memory card.

  When the update of the file system is completed, and when the data amount of the main moving image data has not reached T1 in S812, the control circuit 116 determines that the data amount of the unrecorded sub moving image data accumulated in the buffer area is It is determined whether or not the threshold value T2 has been reached (S815). When the data amount of the sub moving image data accumulated in the buffer area has reached the threshold value T2, the control circuit 116 instructs the host controller 112 to write data for the unit size Uz2, in this case, 8MB data. To do. The host controller 112 issues a write command to the memory card 113, and writes the sub moving image data for the designated unit size from the sub moving image buffer area on the memory 114 to the memory card (S816). This writing process is shown in the period g in the memory card operation of FIG.

  In the file system update setting circuit 205, the update timing for each unit size Uz2 is set. Therefore, the control circuit 116 instructs the host controller 112 to update the file system following the writing of data for the unit size (S817). This file system update operation is performed during the period indicated by h in the memory card operation of FIG. The writing of sub moving image data for one unit size and the updating of the file system are guaranteed by the performance definition unit 2 to be completed within 200 msec. The write performance by the performance definition unit 2 is 40 MB / second. On the other hand, since the data rate of the sub moving image data is 12 MB / second, in FIG. 9, the amount of moving image data stored in the buffer area decreases at a speed of 28 MB / second during the writing of the sub moving image data to the memory card.

  When the update of the file system is completed, and when the data amount of the sub moving image data does not reach T1 in S815, the control circuit 116 determines whether or not there is a recording stop instruction (S818), and the recording stop instruction is issued. If not, the process returns to S811.

  In the present embodiment, the determination as to whether or not the data amount of the main moving image data has reached the threshold value T1 is executed prior to the determination as to whether or not the data amount of the sub moving image data has reached the threshold value T2. Therefore, as shown in FIG. 9, after the start of recording, the timing when the data amount of the main moving image data reaches the threshold value T1 and the timing when the data amount of the sub moving image data reaches the threshold value T2 are both time 901. Since the main moving image data is written to the memory card 113 first, the sub moving image data is accumulated in the buffer area. Then, after the writing of the main moving image data is completed, writing of the sub moving image data is started at time 902. The amount of sub moving image data accumulated in the buffer area at time 902 does not exceed 11.84 MB.

  As described above, in the writing process to the memory card 113, the data amount of the main moving image data and the sub moving image data accumulated in the buffer area does not exceed the size secured as the buffer area, and the buffer overflows. There is no. Therefore, it indicates that the recording of moving image data is not stopped.

  When the recording stop is instructed by the user, the control circuit 116 stops the encoding of the main and sub moving image data by the encoding circuit 109 and stops the accumulation of the encoded data in the buffer area of the memory 114 (S819). ). Then, the control circuit 116 writes the main moving image data and the sub moving image data remaining in the buffer area of the memory 114 to the host controller 112 (S820), updates the file system (S821), and then records. The operation ends. Note that since the size of data written by the write command in S820 does not match the unit size, the writing speed may be reduced. However, since the writing operation is already performed after the instruction to stop recording, there is no problem even if the writing performance is lowered.

  In this way, when recording two moving image data at the same time, it is possible to record a moving image stably while maintaining the writing performance for each data rate by combining the appropriate performance definition units. There is. Further, by selecting the performance definition units in combination so that the writing timing of each moving image data is synchronized, the recording timing of each moving image data can be written so as to be the same, so that the control of the system becomes easy.

  Note that the data rate of the moving image data in this embodiment can be set to a value other than that described in the embodiment. When the performance definition unit is defined as shown in FIG. 4, the video data rate is set to be twice or four times the lowest rate so that any rate of video can be recorded. It is possible to align the write timing. If the unit size of the performance definition unit is other than the values shown in FIG. 4, the write timing can be aligned by determining the rate of the moving image data to be recorded according to the unit size ratio of each performance definition unit. Is possible.

● (Second Embodiment)
Next, a second embodiment will be described. In the first embodiment, the performance definition unit is defined to execute data writing and FAT update processing for a unit size within a predetermined time.

  In the present embodiment, a data write process and a management information write process (FAT update process) are defined for the memory card 113 by separate performance definition units. FIG. 10 is a diagram showing access conditions by the performance definition unit defined in the memory card 113 of this embodiment. The access conditions by the performance definition unit 5 are unit size = 16 MB, Tuw = 300 msec, and the write speed is 53 MB / sec. The access conditions by the performance definition unit 6 are unit size = 8 MB, Tuw = 180 msec, and the write speed is 44 MB / sec. The access conditions by the performance definition unit 7 are unit size = 4 MB, Tuw = 110 msec, and a writing speed of 36 MB / sec. The access conditions by the performance definition unit 8 are unit size = 2 MB, Tuw = 80 msec, and a performance of 25 MB / sec as a writing speed. The performance definition unit 9 defines access conditions for updating the file system.

  Also in this embodiment, the configuration of the digital video camera 100 is the same as that of the first embodiment. The operation when recording one moving image data will be described below. In this embodiment, as shown in FIG. 10, a performance definition unit for updating the FAT is defined. Therefore, in addition to performing FAT update for each writing of moving image data, it is also possible to perform FAT updating for each moving image writing. In this case, the writing of moving image data for the unit size in the selected performance definition unit is continuously executed except for the FAT update execution timing.

  In the present embodiment, when the screen size, data rate, and recording format of a moving image to be recorded are set by the user, the processing in FIG. 5A is executed. The control circuit 116 determines whether to record one moving image or two moving images simultaneously according to the set recording format (S501). In the case of setting to record one moving image, the control circuit 116 sets the screen size in the image size setting circuit 202 and sets the data rate of the moving image in the data rate setting circuit 203 based on the user setting (S502). . Next, the unit size setting circuit 204 calculates and sets the unit size based on the set recording format and moving image data rate (S503). Specifically, a unit size is set by a performance definition unit having a writing speed exceeding the set moving image data rate. For example, in this embodiment, a case where 50 MB / second is set as the data rate of moving image data will be described. In this case, among the performance definition units shown in FIG. 10, a unit size of 16 MB is set by the performance definition unit 5 having a writing speed exceeding this.

  Further, the control circuit 116 sets the file system update frequency in the file system update setting circuit 205 (S504). In the present embodiment, the setting is made so that the FAT is updated every time writing of unit-size moving image data is executed three times. Note that the longer the FAT update interval, the higher the rate of the moving image data to be recorded. However, if a momentary interruption occurs due to the battery being removed during recording, the length of the moving image that cannot be normally reproduced is increased. become longer.

  Next, the buffer area setting circuit 206 sets the size of the buffer area required for recording from the set unit size. Then, an area of the set size is secured in the memory 114 as a buffer memory area for moving image data (S505). According to the performance definition unit 6, since the unit size (Uz) is 16 MB, a size larger than 16 MB is secured as the buffer area. In addition, a unit size is set as a threshold value T for the amount of data stored in the buffer memory area, which is used to determine the timing for writing moving image data to the memory card 113.

  Next, moving image data recording processing according to the present embodiment will be described. FIG. 11 is a flowchart showing the recording process of the present embodiment. FIG. 12 is a diagram showing the update operation of the moving image data stored in the buffer area, the data written to the memory card 113, and the file system after the start of recording. FIG. 12 shows a case where the performance definition unit 6 is selected as described above, and further, FAT update is performed every three writing of moving image data.

  In the recording standby state, when the user operates the operation circuit 115 to give an instruction to start recording, the moving image data from the image sensor 103 is processed by the image processing circuit 105 and stored in the frame memory 106. The image size conversion circuit 108 converts the size of each screen of the moving image data stored in the frame memory 106 so as to be the image size set by the image size setting circuit 202 and stores it in the memory 114. The encoding circuit 109 reads and encodes the moving image data stored in the memory 114 and stores it in the buffer area on the memory 114 set by the buffer area setting circuit 206. At this time, the encoding circuit 109 performs encoding so that the data rate of the encoded moving image data does not exceed the upper limit rate determined by the set data rate (S1101).

  Next, the control circuit 116 determines whether or not the amount of unrecorded moving image data accumulated in the buffer area has reached a threshold value T (S1102). When the data amount of the moving image data accumulated in the buffer area exceeds the threshold value T, the control circuit 116 instructs the host controller 112 to write data for the unit size Uz, here, 16 MB. The host controller 112 issues a write command to the memory card 113, and writes moving image data for the designated unit size from the buffer area on the memory 114 to the memory card (S1103). This writing process is shown in the period i in the memory card operation of FIG.

  When one writing is completed, the control circuit 116 determines whether or not the writing has been completed N times, in this case, three times (S1104). If N times of writing have not been completed, the process returns to S1103, and the control circuit 116 instructs the host controller 112 to write moving image data for the unit size again.

  Thus, when N times of writing are completed, the control circuit 116 instructs the host controller 112 to execute the file system update (S1105). This file system update operation is performed during the period indicated by j in the memory card operation of FIG. When the update of the file system is completed, the control circuit 116 determines a recording stop instruction (S1106). If there is no instruction to stop recording, the process returns to S1102. That is, writing of moving image data to the memory card 113 is started when the data amount of moving image data accumulated in the buffer area reaches the threshold T again after the FAT update.

  As described above, writing of moving image data for one unit size is guaranteed to be completed within 300 msec, so that writing of moving images for the unit size is executed three times in succession, so that 16 × 3 = 48 MB is 900 msec. Is guaranteed to be written in. The file system update is guaranteed to be completed within 20 msec by the performance definition unit 9.

  Therefore, even when the FAT is updated after writing 16 MB of moving image data three times in succession, the amount of data stored in the buffer area does not exceed 16 MB, and the buffer does not overflow. Therefore, it indicates that the recording of moving image data is not stopped.

  When the user gives an instruction to stop recording, the control circuit 116 stops encoding moving image data by the encoding circuit 109 and stops storing encoded data in the memory 114 (S1107). Then, the control circuit 116 writes the moving image data remaining in the buffer area to the host controller 112 (S1108), updates the file system (S1109), and ends the recording operation.

  As described above, in this embodiment, access conditions for data writing and FAT update are defined by separate performance definition units. Then, by appropriately setting the frequency of FAT update, it is possible to set the rate of moving image data to a rate close to the writing speed defined by the performance definition unit.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (9)

Processing means for generating video data;
Recording means for writing the moving image data to the recording medium by outputting a write command to the recording medium;
A data amount of moving image data written to the recording medium by one write command is set from a plurality of predetermined data amounts, and the moving image data having the set data amount is set on the recording medium by one write command. Control means for controlling the recording means to write;
In accordance with a predetermined file system, has a management means for managing the moving image data recorded on the recording medium as a file,
For each of the plurality of predetermined data amounts, a writing speed of the recording medium and an execution time for writing data by one writing command are defined in the recording medium,
The recording means records management information corresponding to the file system on the recording medium, and an execution time for writing data by the write command includes a time for recording the management information on the recording medium. record apparatus shall be the feature that it contains. Processing means for generating video data;
Recording means for writing the moving image data to the recording medium by outputting a write command to the recording medium;
A data amount of moving image data written to the recording medium by one write command is set from a plurality of predetermined data amounts, and the moving image data having the set data amount is set on the recording medium by one write command. Control means for controlling the recording means to write;
In accordance with a predetermined file system, has a management means for managing the moving image data recorded on the recording medium as a file,
For each of the plurality of predetermined data amounts, a writing speed of the recording medium and an execution time for writing data by one writing command are defined in the recording medium,
The recording means includes
Management information corresponding to the file system is recorded on the recording medium,
Recording the management information on the recording medium by outputting a command to instruct the updating to the recording medium;
Run time for recording the management information by the command for instructing one of the updates, characterized in that it is defined in the recording medium record device. The recording apparatus according to claim 1 , wherein the larger the predetermined amount of data, the faster the writing speed or the shorter execution time is defined for the recording medium. A setting unit for setting a data rate of the moving image data generated by the processing unit;
The control means sets a data amount of moving image data written to the recording medium by one write command from the plurality of predetermined data amounts according to a data rate of the moving image data. The recording apparatus according to claim 1 or 2 . The recording means includes a mode for simultaneously recording two moving image data on the recording medium,
The control means is configured to record a moving image written on the recording medium by a single write command in order to record the two moving image data in accordance with a data rate of the two moving image data recorded simultaneously in the mode. The recording apparatus according to claim 4 , wherein a data amount of data is set. Processing means for generating video data;
Recording means for writing the moving image data to the recording medium by outputting a write command to the recording medium;
A management unit for managing moving image data recorded on the recording medium as a file according to a predetermined file system ,
A data amount of moving image data written to the recording medium by one write command is set from a plurality of predetermined data amounts, and the moving image data having the set data amount is set on the recording medium by one write command. control means to write that have a control step for controlling the recording device,
For each of the plurality of predetermined data amounts, a writing speed of the recording medium and an execution time for writing data by one writing command are defined in the recording medium,
The recording means records management information corresponding to the file system on the recording medium, and an execution time for writing data by the write command includes a time for recording the management information on the recording medium. control method for a recording apparatus, characterized in that it contains. Processing means for generating video data;
  Recording means for writing the moving image data to the recording medium by outputting a write command to the recording medium;
  A management unit for managing moving image data recorded on the recording medium as a file according to a predetermined file system,
  A data amount of moving image data written to the recording medium by one write command is set from a plurality of predetermined data amounts, and the moving image data having the set data amount is set on the recording medium by one write command. The control means has a control step for controlling the recording means to write,
  For each of the plurality of predetermined data amounts, a writing speed of the recording medium and an execution time for writing data by one writing command are defined in the recording medium,
  The recording means includes
    Management information corresponding to the file system is recorded on the recording medium,
    Recording the management information on the recording medium by outputting a command to instruct the updating to the recording medium;
  An execution time for recording the management information by a command for instructing one update is defined in the recording medium. Processing means for generating video data;
Recording means for writing the moving image data to the recording medium by outputting a write command to the recording medium;
According to a predetermined file system, said management means for managing the moving image data recorded on the recording medium as a file, the computer of the recording apparatus having the recording apparatus according to any one of claims 1 to 5 , A program for functioning as each means excluding the processing means and the recording means. A computer-readable recording medium storing the program according to claim 8 .

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