JP2015080149A - Video recording device and video recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video recording device that allows improving data transfer speed, and to provide a video recording method.SOLUTION: A video recording device 1 including a plurality of SSDs 10 connected in parallel to one another includes: a plurality of FIFO circuit sections 21 transferring data for writing to each of the plurality of SSDs 10; a DRAM 30 temporarily storing division data in which an input video signal is divided; and a writing control section 22 extracting the division data from the DRAM 30, sequentially selecting a writing destination from the plurality of SSDs 10, and transferring the division data to the corresponding FIFO circuit section 21.

Description

  The present invention relates to a video recording apparatus and a video recording method for high-definition video.

  In recent years, cameras for ultra-high-definition video (4K UHDTV (Ultra High Definition Television)) with more than 2000 scanning lines and higher definition than HDTV (High Definition Television) have been used in the digital cinema industry or medical applications. It is used. Furthermore, a camera for ultra-high definition video (8K UHDTV, Super Hi-Vision) having more than 4000 scanning lines is also being studied as a next-generation broadcasting system.

  Super high-definition video signals have a very high uncompressed data rate of 24 Gbps (dual green) to 144 Gbps (full spec), so a high transfer rate is also required for video recording devices. In order to improve the transfer rate, a method is adopted in which storage devices are provided in parallel and the divided data is distributed and recorded in a plurality of devices (for example, see Patent Document 1).

  By the way, NAND flash memory, which has recently been increased in speed and capacity, is a recording element suitable for writing large-capacity data such as video, and is widely used as a recording element for digital cameras. A typical recording device composed of NAND flash memory is SSD (Solid State Drive). A video recording apparatus for Super Hi-Vision realizes high-speed signal recording by paralleling storage devices such as SSDs.

JP2013-080409A

  However, SSD can write and read high-speed random data, but has a feature that an instantaneous speed drop occurs when continuous data is written. When a video signal is recorded using a recording device having an unstable data transfer rate, that is, a writing speed, the transfer speed of the entire apparatus may be reduced due to this speed reduction.

  An object of the present invention is to provide a video recording apparatus and a video recording method capable of improving the data transfer rate.

  A video recording apparatus according to the present invention is a video recording apparatus in which a plurality of recording devices are connected in parallel, and a plurality of FIFO circuit units for transferring write data to each of the plurality of recording devices, and an input Temporary storage unit for temporarily storing divided data obtained by dividing the video signal, and extracting the divided data from the temporary storage unit, sequentially selecting write destinations from the plurality of recording devices, and corresponding FIFO circuit units And a writing control unit for transferring the divided data.

  According to this configuration, the video recording apparatus avoids the influence of an instantaneous speed reduction in a recording device with an unstable data transfer rate when recording high-definition video data in parallel on a plurality of recording devices. For parallel recording control. The video recording apparatus can avoid data overflow in the FIFO circuit section by temporarily storing the divided data using the temporary storage section. As a result, the video recording apparatus can improve the data transfer speed to the recording device and record high-definition video data.

  The write control unit divides the input video signal into frames and stores them in the temporary storage unit, and transfers the divided data configured in units of frames to a FIFO circuit unit corresponding to the write destination. Also good.

  According to this configuration, the video recording apparatus divides the video data for each frame, buffers the divided data for each frame, and then transfers the divided data to the recording device via the FIFO circuit unit. When the frame is further divided, the bus utilization efficiency decreases due to an increase in overhead of the data transfer command. However, by transferring the frame unit, the video recording apparatus improves the bus utilization efficiency and transfers the entire apparatus. Speed can be increased.

  You may provide the management data memory | storage part which memorize | stores the management data which show the relationship between the said division | segmentation data and the said recording device in which the said division | segmentation data was written.

  According to this configuration, the video recording apparatus can read the recorded video data correctly and easily by storing the management data indicating the relationship between the divided data and the recording device.

  The write control unit may change the selection order of the write destination when the transfer of the divided data to the recording device is not completed.

  According to this configuration, the video recording apparatus changes the selection order of the recording devices when the transfer rate of the selected recording device is low and the transfer of the divided data is not completed. Therefore, the data overflow in the FIFO circuit unit is prevented. The parallel recording can be performed efficiently while avoiding the above, and the transfer speed of the entire apparatus can be increased.

  The video recording apparatus may include a measurement unit that measures a transfer rate to the recording device, and an output unit that outputs notification information based on a measurement result by the measurement unit.

  According to this configuration, the video recording apparatus measures the transfer rate to the recording device. By outputting this measurement result, the administrator can grasp the writing performance of the recording device and can replace the deteriorated recording device in a timely manner.

  The video recording apparatus includes a measurement unit that measures a transfer rate to the recording device, and the writing control unit selects the writing destination from a predetermined number of recording devices among the plurality of recording devices, and When the measurement result by the measurement unit is less than a predetermined level, a recording device other than the predetermined number may be selected as the writing destination instead of the recording device that does not satisfy the predetermined level.

  According to this configuration, the video recording apparatus switches writing to the recording device whose transfer rate does not reach a predetermined level to the spare recording device. Therefore, the video recording apparatus can recover the transfer rate lowered due to the deterioration of the recording device and increase the transfer speed of the entire apparatus.

  According to the video recording method of the present invention, a video recording apparatus includes a plurality of FIFO circuits that connect a plurality of recording devices in parallel and transfer write data to each of the plurality of recording devices. A method for temporarily storing divided data obtained by dividing an input video signal; extracting the divided data; sequentially selecting a writing destination from the plurality of recording devices; and transferring the divided data And a writing control step to execute.

  According to the present invention, the data transfer speed in video recording is improved.

It is a block diagram which shows the function structure of a video recording device. It is a conceptual diagram which shows the data transfer speed in each of several SSD. It is a figure which shows an example of the table stored in a management data storage part. It is a figure which shows the 1st pattern of the video recording method by a video recording device. It is a figure which shows the 2nd pattern of the video recording method by a video recording device. It is a figure which shows the 3rd pattern of the video recording method by a video recording device.

Hereinafter, an example of an embodiment of the present invention will be described.
The video recording apparatus 1 according to the present embodiment records a high-definition video signal (for example, 24 Gbps or more) or a compressed signal thereof on a plurality of recording devices with unstable data transfer rates using a flash memory or the like. As an example, the recording device of this embodiment is an SSD using a NAND flash memory.

FIG. 1 is a block diagram showing a functional configuration of the video recording apparatus 1.
The video recording apparatus 1 includes a plurality of SSDs 10, a controller 20, a DRAM 30 (temporary storage unit), a management data storage unit 40, and a display unit 50.

  In the SSD 10, a predetermined number of normally used devices (SSD — 1 to SSD — 16) and spare devices (SSD — 17 to) are connected in parallel with the controller 20.

  The controller 20 controls the entire video recording apparatus 1, receives video data as input, and transfers write data to the SSD 10. The input video data is, for example, an uncompressed video signal output from a video camera, a player, or the like, or data encoded at a predetermined compression rate, audio, subtitles, camera parameters, proxy images, etc. The metadata may be added.

  The controller 20 includes a plurality of FIFO circuit units 21, a write control unit 22, a measurement unit 23, and an output unit 24 corresponding to each of the SSDs 10.

The FIFO circuit unit 21 is provided for each of the plurality of SSDs 10 and transfers the data for writing to the SSDs 10 through the FIFO queue while buffering the data for writing.
The plurality of FIFO circuit units 21 are connected to the write control unit 22 via, for example, a bus.

  The writing control unit 22 stores the divided data obtained by dividing the input video signal for each frame or further dividing the frame in the DRAM 30. When the temporarily stored divided data is extracted from the DRAM 30, the write control unit 22 sequentially selects a write destination from a predetermined number of SSDs 10 and transfers the divided data to the corresponding FIFO circuit unit 21. Specifically, for example, SSD_1 to SSD_16 are selected in order.

  Here, when transferring the divided data to the FIFO circuit unit 21, the write control unit 22 changes the selection order of the write destination if the transfer of the divided data to the SSD 10 is not completed. For example, the write control unit 22 skips data transfer to the FIFO circuit unit 21 corresponding to the SSD 10 during the writing process, and transfers the data to the FIFO circuit unit 21 in the next order.

FIG. 2 is a conceptual diagram showing the data transfer rate in each of the plurality of SSDs 10.
In the SSD 10, for example, an instantaneous speed reduction occurs due to generation of a task such as wear leveling. The occurrence timing and the occurrence frequency of this speed decrease are also difficult to predict due to large individual differences between devices.
Therefore, when write data is continuously transferred, there is a possibility that data overflow may occur in the queue of the FIFO circuit unit 21 due to an unpredictable speed reduction.

The measurement unit 23 measures the transfer rate of write data for each of the plurality of SSDs 10.
In the SSD 10, performance deterioration proceeds due to the characteristics of the NAND flash memory which is a recording element. In addition, recording devices with low performance may be mixed due to individual differences. The measurement unit 23 can determine the write performance by measuring the transfer rate for each SSD 10.

  Here, when the measurement result by the measurement unit 23 is less than a predetermined level among the predetermined number of SSDs 10, the write control unit 22 replaces the SSD 10 that does not satisfy the predetermined level with a spare SSD 10 (for example, SSD_17) is selected as the write destination.

  The output unit 24 outputs notification information based on the measurement result by the measurement unit 23 to the display unit 50. The administrator of the video recording apparatus 1 can perform measures such as replacement of the SSD 10 in a timely manner based on the notification information.

The DRAM 30 is a temporary storage area used by the controller 20 for work, and temporarily stores divided data obtained by dividing the input video signal. Thereby, the queue overflow in the FIFO circuit unit 21 is suppressed.
In this embodiment, divided data in units of frames or data obtained by dividing a frame into a predetermined number (for example, divided into 16 pieces of the same number as the SSD 10) is stored.

  The management data storage unit 40 stores management data indicating the relationship between the divided data and the SSD 10 in which the divided data is written.

FIG. 3 is a diagram illustrating an example of a table stored in the management data storage unit 40.
In this example, the number of divided data (frame number) configured in units of frames and the number (1 to 16) of the SSD 40 are associated with each other. For example, frames 1 to 16 are recorded from SSD_1 to SSD_16, and subsequent frames 17 to 32 are sequentially recorded again from SSD_1 to SSD_16.

FIG. 4 is a diagram showing a first pattern of the video recording method by the video recording apparatus 1.
In the first pattern, the write control unit 22 directly transfers the divided data to the FIFO circuit unit 21 without temporarily storing the divided data in the DRAM 30.

When receiving the video data, the writing control unit 22 sequentially transfers the divided data for each line to the plurality of SSDs 10 via the FIFO circuit unit 21.
In this case, if an instantaneous speed drop occurs in one or more of the plurality of SSDs 10, data overflow may occur on the FIFO circuit unit 21 and data may be lost.

FIG. 5 is a diagram showing a second pattern of the video recording method by the video recording apparatus 1.
In the second pattern, the write control unit 22 avoids data overflow in the FIFO circuit unit 21 by temporarily storing the divided data in the DRAM 30.

The write controller 22 divides one frame of video data into 16 lines or spaces, and buffers the divided data in the DRAM 30. When the write control unit 22 extracts the divided data from the DRAM 30, the write control unit 22 performs parallel recording on the 16 SSDs 10 via the FIFO circuit unit 21.
Thereby, overflow of data in the FIFO circuit unit 21 is avoided by the buffer on the DRAM 30.

  Note that the capacity of the buffer of the divided data temporarily stored in the DRAM 30 is preferably one frame or more, for example, several frames.

FIG. 6 is a diagram showing a third pattern of the video recording method by the video recording apparatus 1.
In the third pattern, the write control unit 22 buffers the divided data for each frame in the DRAM 30.

When the write control unit 22 extracts the divided data from the DRAM 30, the write control unit 22 performs parallel recording on the 16 SSDs 10 via the FIFO circuit unit 21. Thereby, one frame of data is recorded on one SSD 10.
At this time, the write control unit 22 stores management data indicating in which SSD 10 the frame data is recorded in the management data storage unit 40.

  The write control unit 22 can avoid data overflow in the FIFO circuit unit 21 by buffering the divided data in the DRAM 30. Furthermore, the write control unit 22 can write the data to the SSD 10 in units of frames, thereby reducing the number of data transfer commands issued and improving the bus utilization efficiency compared to the second pattern for dividing the frame. .

  The capacity of the buffer of the divided data temporarily stored in the DRAM 30 is preferably 16 frames or more, for example, about 32 to 48 frames.

  According to the present embodiment, the video recording apparatus 1 performs parallel recording control for avoiding the influence of an instantaneous speed decrease in the flash memory when recording high-definition video data in parallel on a plurality of SSDs 10. Do. The video recording apparatus 1 can avoid data overflow in the FIFO circuit unit 21 by temporarily storing the divided data using the DRAM 30. As a result, the video recording apparatus 1 can improve the data transfer speed to the SSD 10 and record high-definition video data.

  The video recording apparatus 1 divides the video data for each frame, buffers the divided data for each frame, and then transfers the data to the SSD 10 via the FIFO circuit unit 21. When the frame is further divided, the bus utilization efficiency decreases due to an increase in overhead of the data transfer command. However, by transferring the frame unit, the video recording apparatus 1 improves the bus utilization efficiency and improves the overall apparatus. The transfer speed can be increased.

  The video recording apparatus 1 can read the recorded video data correctly and easily by storing management data indicating the relationship between the divided data and the SSD 10.

  Since the video recording apparatus 1 changes the selection order of the SSD 10 when the transfer rate of the selected SSD 10 is low and the transfer of the divided data is not completed, the overflow of the data in the FIFO circuit unit 21 is avoided and the efficiency is improved. Since parallel recording can be executed, the transfer speed of the entire apparatus can be increased.

  The video recording apparatus 1 measures the transfer rate to the SSD 10. By outputting this measurement result, the administrator can grasp the write performance of the SSD 10 and replace the deteriorated SSD 10 in a timely manner.

  The video recording apparatus 1 switches writing to the SSD 10 whose transfer rate does not reach a predetermined level to the spare SSD 10. Therefore, the video recording apparatus 1 can recover the transfer rate that has been lowered due to the deterioration of the flash memory, and increase the transfer speed of the entire apparatus.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. Further, the effects described in the present embodiment are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the present embodiment.

  In the present embodiment, the configuration and operation of the video recording apparatus have been mainly described. However, the present invention is not limited to this, and may be configured as a method or program for recording video data including each component. .

  Further, it may be realized by recording a program for realizing the function of the video recording apparatus on a computer-readable recording medium, causing the computer system to read and execute the program recorded on the recording medium. .

  The “computer system” here includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a hard disk built in the computer system.

  Furthermore, “computer-readable recording medium” means that a program is dynamically held for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. It is also possible to include one that holds a program for a certain time, such as a volatile memory inside a computer system that becomes a server or client in that case. Further, the program may be for realizing a part of the above-described functions, and may be capable of realizing the above-described functions in combination with a program already recorded in the computer system. .

1 Video recording device 10 SSD
20 controller 21 FIFO circuit section 22 write control section 23 measurement section 24 output section 30 DRAM (temporary storage section)
40 management data storage unit 50 display unit

Claims (7)

A video recording apparatus in which a plurality of recording devices are connected in parallel,
A plurality of FIFO circuit units for transferring write data to each of the plurality of recording devices;
A temporary storage unit that temporarily stores divided data obtained by dividing the input video signal;
A video recording apparatus comprising: a write control unit that extracts the divided data from the temporary storage unit, sequentially selects a write destination from the plurality of recording devices, and transfers the divided data to a corresponding FIFO circuit unit.   The write control unit divides the input video signal into frames and stores them in the temporary storage unit, and transfers the divided data configured in units of frames to a FIFO circuit unit corresponding to the write destination. Item 2. The video recording apparatus according to Item 1.   The video recording apparatus according to claim 1, further comprising a management data storage unit that stores management data indicating a relationship between the divided data and the recording device in which the divided data is written.   4. The video recording apparatus according to claim 1, wherein the writing control unit changes a selection order of the writing destination when transfer of the divided data to the recording device is not completed. 5. A measurement unit for measuring a transfer rate to the recording device;
The video recording apparatus according to claim 1, further comprising: an output unit that outputs notification information based on a measurement result by the measurement unit. A measurement unit for measuring a transfer rate to the recording device;
The writing control unit selects the writing destination from a predetermined number of recording devices among the plurality of recording devices, and when the measurement result by the measuring unit does not satisfy a predetermined level, the writing control unit does not satisfy the predetermined level 6. The video recording apparatus according to claim 1, wherein a recording device other than the predetermined number is selected as the writing destination in place of the recording device. A video recording method for a video recording apparatus comprising a plurality of FIFO circuit units for connecting a plurality of recording devices in parallel and transferring write data to each of the plurality of recording devices,
A temporary storage step for temporarily storing divided data obtained by dividing the input video signal;
And a writing control step of extracting the divided data, sequentially selecting a writing destination from the plurality of recording devices, and transferring the divided data.

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