JP2012191499A - Recording and reproducing device and recording and reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm recorded data contents in a short time.SOLUTION: A recording and reproducing device related to this embodiment includes a plurality of file recording units 2-1 to 2-3 and a plurality of hash check processing units 3-1 to 3-3. The file recording units 2-1 to 2-3 divide a recording object file by a prescribed unit and transmit division data to an external memory unit 4. The hash check processing units 3-1 to 3-3 inquire the external memory unit 4 whether or not unprocessed division data of a processing object file is present, preserve a temporary hash value calculated for each division data, and when the unprocessed division data is present, calculate a hash value of the processing object file by updating the temporary hash value using the unprocessed division data.

Description

  Embodiments described herein relate generally to a recording / playback apparatus and a recording / playback method for recording video / audio data and checking the content of the recorded data.

  In an apparatus for recording and reproducing video / audio data, video / audio data input from the outside is recorded on a recording medium. As the recording medium, for example, an optical disk, a hard disk, a semiconductor memory, or the like is used.

  When data recorded on a recording medium is read / written, data corruption occurs with a certain probability. If data corruption occurs in the middle of video / audio data, that portion of the data cannot be played back correctly. For this reason, the video recording / playback apparatus adds an error correction code such as a Reed-Solomon code when writing data to a normal storage medium as a measure against data corruption, and performs error correction processing when reading data.

  Data corruption may also occur when the quality of the transmission path of data read from a storage medium is poor. When a TCP / IP-based communication protocol is used, error correction is possible because an error correction mechanism is incorporated in the protocol. However, if data corruption occurs during data communication between units in the video / audio recording / playback apparatus, or if the order of data packets is switched, error correction may not be possible.

  As a countermeasure against the above problem, a hash value can be used. Read video material from the storage medium, recalculate the hash value from the read data, and check that the hash value calculated in advance matches the recalculated hash value. Can be confirmed to be recorded normally.

JP 2007-257666 A

  However, since one video / audio material data must be recorded before hash check of that data can be started, the recorded video / audio material can be played back immediately using the above recording / playback device at a broadcasting station or the like. If this is desired, the reproduction process is performed without the hash check process, and there is a risk that a broadcast accident will occur.

  An object of the present embodiment is to provide a recording / reproducing apparatus and a recording / reproducing method capable of confirming recorded data contents in a short time.

  The recording / playback apparatus according to the present embodiment includes a plurality of file recording units and a plurality of hash processing units, and the file recording unit includes a dividing unit that divides a recording target file by a predetermined unit, and the dividing unit. Transmitting means for transmitting the divided data divided by the recording device to the recording device, the hash processing unit, the inquiry means for inquiring whether there is unprocessed divided data of the processing target file to the recording device, A storage unit that stores a temporary hash value calculated for each piece of divided data, and if the unprocessed divided data exists, the temporary hash value is updated using the unprocessed divided data. And calculating means for calculating a hash value of the processing target file.

  The recording / playback method according to the present embodiment is a method used in a recording / playback apparatus including a plurality of file recording units and a plurality of hash processing units, and the file recording unit stores a file to be recorded in a predetermined unit. And a transmission step of transmitting the divided divided data to a recording device, and the hash value calculation unit determines whether or not unprocessed divided data of a processing target file exists in the recording device. An inquiry step for inquiring, a storage step for storing a temporary hash value calculated for each of the divided data, and if the unprocessed divided data exists, the temporary hash value is converted into the unprocessed divided value. A calculation step of calculating a hash value of the processing target file by updating using data. That.

The figure which shows the structure of the video recording / reproducing apparatus concerning this embodiment. The block diagram which shows the structure of a file recording unit. The block diagram which shows the structure of a hash check processing unit. The flowchart which shows operation | movement of an image | video recording / reproducing apparatus.

  Hereinafter, a recording / reproducing apparatus and a recording / reproducing method according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a video recording / playback apparatus according to the present embodiment.

  This video recording / playback apparatus includes a plurality of file recording units 2-1 to 2-3 (hereinafter collectively referred to as file recording unit 2) and a plurality of hash check processing units 3-1 to 3-3 (hereinafter referred to as hash check processing units). 3). One unit performs file transfer processing and hash check processing for one transfer. The file recording unit 2 records video / audio data input from the external CPU unit 1 in the external memory unit 4. The hash check processing unit 3 performs hash check processing when reading data recorded in the external memory unit 4.

  FIG. 2 is a block diagram showing the configuration of the file recording unit. The file recording unit 2 divides the received data based on the analysis result of the file data input unit 21 that receives the file data, the data structure analysis unit 22 that analyzes the structure of the received file data, and the data structure analysis unit 22. A data dividing unit 23 for adding management header information to each divided data, and a divided data output unit 24 for transmitting each divided data divided by the data dividing unit 23 to the external memory unit 4 are provided.

  FIG. 3 is a block diagram showing the configuration of the hash check processing unit. The hash check processing unit 3 includes a received file size storage unit 31, a data inquiry unit 32, a divided data input unit 33, a header removal unit 34, a provisional hash value storage unit 35, a hash value calculation unit 36, and an external CPU interface unit 37. Is provided.

  The received file size storage unit 31 manages the file size received by the hash check processing unit 3. The data inquiry unit 32 checks whether there is untransferred file data in the external memory unit 4. The divided data input unit 33 receives data from the external memory unit 4. The header removal unit 34 performs processing for removing data added to the original file data such as header information, error correction code, and padding information from each received divided data. The temporary hash value storage unit 35 temporarily stores an intermediate result of the hash value. The hash value calculation unit 36 performs a hash value update process when new file data is received from the header removal unit 34. The external CPU interface unit 37 communicates with the external CPU unit 1.

  Hereinafter, the operation of the recording / playback apparatus configured as described above will be described.

(Recording process)
Here, an operation when the file recording unit 2 records an MXF file obtained by frame wrapping MPEG data in the OP1a format will be described.

  The file data input unit 21 receives the MXF file from the external CPU unit 1. The data structure analysis unit 22 performs data structure analysis of the MXF file. The data dividing unit 23 divides the data into GOP (Group of Picture) units based on the analysis result. The divided data output unit 24 transmits the data divided by the data dividing unit 23 to the external memory unit 4.

(Hash check processing)
FIG. 4 is a flowchart showing the procedure of the chasing hash process. A case where the chasing hash process is performed on the MXF file being recorded by the hash check processing unit 3 will be described below. When the hash calculation start request arrives from the external CPU unit 1 to the external CPU interface unit 37, the external CPU interface unit 37 initializes the received file size storage unit 31 and the temporary hash value storage unit 35. The external CPU interface unit 37 issues a hash value calculation request for the specified file (processing target file) to the data inquiry unit 32.

  4, the data inquiry unit 32 first sets the timer to 0 (step S2), and inquires of the external memory unit 4 whether there is unprocessed divided data to be transferred next. If it does not exist yet, retry processing is executed after a certain time (step S3: No). When a response indicating that the recording has been completed is returned from the external memory unit 4, the data inquiry unit 32 issues a reception instruction to the divided data input unit 33 (step S3: Yes), and continues the hash check process (step S3). S4).

  That is, after receiving the divided data, the divided data input unit 33 updates the received file size value recorded in the received file size storage unit 31 and sends the received divided data to the header removing unit 34. The header removal unit 34 removes data (header information, error correction code, padding data, etc.) added to the original data at the time of file recording and sends the data to the hash value calculation unit 36. The hash value calculation unit 36 reads the halfway result of the hash value from the temporary hash value storage unit 35 and performs a hash value update process using the data from the header removal unit 34. The updated hash value is recorded in the temporary hash value storage unit 35.

  The processing from step S2 to step S4 is repeated until a retry timeout or all the file data is received from the external memory unit 4 and the hash value of the file is obtained (step S5). When the reception of all data is completed, the hash check process is terminated (step S6), and the external CPU interface unit 37 transmits the hash value calculation result to the external CPU unit 1.

  As described above, according to the present embodiment, it is possible to realize a chasing hash process in which a hash check process is executed in parallel with data recording, and the recorded data contents can be confirmed in a short time. become. Since each transfer is handled by an independent processing unit, if the interface of the external memory unit is sufficiently fast, the individual processing speed will not decrease even if a plurality of chasing hash processes are executed. Further, since the CPU of each unit is inexpensive, it can be realized at a relatively low cost.

  Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... External CPU unit, 2-1 to 2-3 ... File recording unit, 3-1 to 3-3 ... Hash check processing unit, 4 ... External memory unit, 21 ... File data input part, 22 ... Data structure analysis part 23 ... Data division unit, 24 ... Division data output unit, 31 ... Received file size storage unit, 32 ... Data inquiry unit, 33 ... Division data input unit, 34 ... Header removal unit, 35 ... Provisional hash value storage unit, 36: Hash value calculation unit, 37: External CPU interface unit.

Claims (4)

A plurality of file recording units and a plurality of hash processing units;
The file recording unit is
A dividing means for dividing the recording target file into predetermined units;
Transmission means for transmitting the divided data divided by the dividing means to a recording device,
The hash processing unit is:
Inquiry means for inquiring whether there is unprocessed divided data of the processing target file in the recording device;
Storage means for storing a provisional hash value calculated for each of the divided data;
A calculation unit configured to calculate a hash value of the processing target file by updating the provisional hash value with the unprocessed divided data when the unprocessed divided data exists; Recording and playback device.   2. The recording / reproducing apparatus according to claim 1, wherein the dividing unit divides the recording target file in units of GOPs. A method used in a recording / playback apparatus comprising a plurality of file recording units and a plurality of hash processing units,
The file recording unit is
A division step of dividing the recording target file into predetermined units;
A transmission step of transmitting the divided divided data to a recording device,
The hash processing unit is:
An inquiry step for inquiring whether there is unprocessed divided data of the processing target file in the recording device;
A storage step of storing a provisional hash value calculated for each of the divided data;
A calculation step of calculating a hash value of the processing target file by updating the temporary hash value with the unprocessed divided data when the unprocessed divided data exists. Recording and playback method.   4. The recording / reproducing method according to claim 3, wherein in the dividing step, the recording target file is divided in units of GOP.

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