JP2002237139A - Data recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data recording and reproducing device capable of surely accessing all data blocks and accessing a data block succeeding the data block which is made unreadable. SOLUTION: The data recording and reproducing device is provided with a recording part 1 for recording a file which registers various data in the unit of the data block consisting of management information, such as data, and the size, the number and the kind of the data on a recording medium 2, a reproducing part 3 for acquiring a leading position of the succeeding data block, and reading the succeeding data block on the basis of the data size within the management information in the above data block, and a normal retrieval means 4 for retrieving the data block in the file on the basis of the kind of data within the management information in the data block read by the reproducing part 3. In the above data recording and reproducing device, the offset data block in which the offset value to the leading position of some data blocks included in the file from the arbitrary reference position in the file is registered is registered in the arbitrary position of the file.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording / reproducing apparatus for a recording medium for reading / writing a file in which various data are registered in data block units.

[0002]

2. Description of the Related Art When recording various data on a recording medium, transferring the data via a network, or distributing the data, the data itself and the type of the data, or the entire data in order to access the data, are required. Management information for managing the data, which indicates where and in what form the data exists, is required.

[0005] For example, as shown in FIG. 18, a case where a file name is stored in one entry for the purpose of managing a file name of recorded data is considered. In this case, the management information area (data block) for storing the file name has a variable length depending on the number of existing files. Therefore, it is necessary to know the management information data area.

Therefore, by storing the number of files at an arbitrary fixed position in the management information (the top position of the management information in the example of FIG. 18), the information area managing the file name can be grasped. It is possible to do. Here, a data block is a group of several data groups such as file names and management information such as the number of data for managing the data groups.

Further, as shown in FIG. 19, a case is considered where a plurality of image data are managed in one file. At this time, when the image data is compressed using the variable length coding algorithm, the data sizes of the individual image data are different. Therefore, in order to access each image data, management information indicating the data size of each data is required.

In the above two examples, the number of data and the data size are variable length. Therefore, the end position of the data block can be known from the management information such as the number of data added to an arbitrary position in the file and the size of the data. It is possible.

As described above, by adopting a form in which the data length is added to the beginning of a data block, when a plurality of data blocks are continuously recorded, by skipping the data block size from the beginning of the file, the subsequent Data blocks to be accessed. By repeating this in the file, a data block in the file can be searched.

[0008] Qu is a file format of AV data.
In the case of ickTime, as shown in FIG. 20, one group of data blocks is represented by a unit called atom.
In this example, a header for storing the size of the atom in units of bytes in the first four bytes and a header for storing the type of the atom in the subsequent four bytes are added to the beginning of the data.

[0009] Therefore, the size and type of the first atom can be known from the first 8 bytes of the QuickTime file, and seek from the beginning of the file by the size of the first atom (adding the size of the atom to the start address of the atom) By moving to the address), it is possible to access the subsequent atom.

In addition to the atom, not only can the atom be continuously recorded in the file, but also the trak at in the moov atom in FIG.
Like om, it is possible to have more atoms in an atom, and atoms can be nested.

Here, the moov atom is an atom in which management information of data in the mdat atom in which some AV data is recorded is registered. Also, the trak atom is moov
An atom that exists in the atom and holds the management information required to play back audio and images.

To search for any atom in the file,
Read the atom header from the beginning of the file,
Check if the type of atom is the desired atom. If the type of the first atom is not the desired atom, the first at
Skip the data size of om from the beginning of the file,
Fetch the header information of the following atom.

From the header information of the acquired atom, it is confirmed whether the type of the atom is the target atom. By repeating this until the end of the file, the target atom can be searched. With the above access method, QuickTime
Any atom in the file can be searched.

[0014]

However, in the above-mentioned prior art, management information and data of subsequent data are accessed by management information indicating the number and size of data. In the case of a medium, it is conceivable that dust or scratches adhere to the recording surface or that data is overwritten on an erroneous location due to an impact applied during recording.

In such a case, as shown in FIGS. 21 and 22, a value different from the originally registered data is read out as management information, and it is impossible to access a subsequent data block. Becomes

FIG. 21 shows an example in which management information indicating the number of data items held in one data block cannot be read correctly, and the end position of this data block is indicated in an incorrect position.

This is because if the next data block exists next to the number of data registered from the beginning of the data block and the value representing the number of data is not correct, the wrong number is used as the valid data. Because it is treated as data,
This is because the header area of the next data block is erroneously recognized, and the data of the subsequent data block cannot be correctly read.

FIG. 22 shows an example in which the data block, which is the management information of the data block of the image data, cannot be read correctly, so that the middle of the image data is set as the end position of the data block. This is because if the size of the image data is not correct, the reading position of the subsequent data is not correct, so that the subsequent data cannot be read correctly.

Further, as shown in FIG.
If the header information of the atom in the file cannot be read correctly, access to the subsequent atom cannot be performed correctly even if the header and data of the subsequent atom have the correct values as described above.

This is because the size which is the header information of the atom cannot be read correctly, and the position of the incorrect size from the head address of the focused atom is replaced by the next atom.
This is because it is handled as header information.

[0021] The present invention has been made in view of the above-mentioned problems, and it is possible to reliably access a backup data block of AV data management information, and to avoid a problem in recording / reproducing AV data. It is intended to provide a data recording / reproducing apparatus capable of performing the above.

[0022]

According to a first aspect of the present invention, a file in which various types of data are registered is recorded on a recording medium in units of data blocks including data and management information including the size, number, and type of the data. Recording means for performing, a reproducing means for obtaining a starting position of a subsequent data block based on a data size in management information in the data block, and reading the subsequent data block; and a data block read by the reproducing means. And a search means for searching for a data block in the file based on the data type in the management information in the file. Register the offset data block in which the offset value to the head position of the block is registered at an arbitrary position in the file. It is characterized in.

The second invention of the present application is characterized in that the size of the offset data block is fixed.

According to a third aspect of the present invention, the size of the offset data block is variable.

According to a fourth aspect of the present invention, the data block includes a data block in which AV data is registered,
And a data block in which management information for managing the recording / reproducing mode of the data block of the AV data is registered.

According to a fifth aspect of the present invention, a copy of a data block in which the management information of the AV data is registered is registered in a file as a backup, and the management information is backed up from an arbitrary reference position in the file. The offset value to the data block is registered in the offset data block.

According to a sixth aspect of the present invention, there is provided an abnormality detecting means for detecting an abnormality in the reproduced data read by the reproducing means, and when the abnormality detecting means detects an abnormality in the reproduced data, the offset data block. And an abnormal-time search means for searching for an arbitrary data block based on the offset value registered in (1).

According to a seventh aspect of the present invention, when an abnormality is detected in the original data block in which the management information of the AV data is registered by the abnormality detecting means, the abnormal state searching means sets the offset data block to Based on the registered offset value, a backup data block in which the management information of the AV data is registered is searched, and based on the backup data block of the management information,
It is characterized by reproducing data.

According to an eighth aspect of the present invention, an original data block in which the management information of the AV data in which the abnormality is detected is registered using a backup data block in which the management information of the AV data is registered. Is restored.

According to a ninth aspect of the present invention, when an abnormality is detected in the management information of the data block by the abnormality detecting means,
The abnormality-time search means restores the management information of the data block in which the abnormality has been detected, using the offset value registered in the offset data block.

According to a tenth aspect of the present invention, there is provided a recording means for recording, on a recording medium, a file in which various types of data are registered in units of data blocks comprising data and management information including the size, number, and type of the data, Based on the data size in the management information in the data block, a reproducing unit that obtains the head position of the subsequent data block and reads the subsequent data block; and a reproducing unit that reads out the subsequent data block in the management information in the data block read by the reproducing unit. In a data recording / reproducing apparatus including a normal search unit for searching for a data block in a file based on a data type, an external reference data block in which the location of data existing outside the file is registered is located at an arbitrary position in the file. It is characterized by being registered.

According to an eleventh aspect of the present invention, the data block includes a data block in which AV data is registered, and a data block in which management information for managing a recording / reproducing mode of the data block of the AV data is registered. And a block.

According to a twelfth aspect of the present invention, a copy of a data block in which the management information of the AV data is registered is registered outside the file as a backup, and the location of the backup data block of the management information is stored in the external storage. It is characterized in that it is registered in a reference data block.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the data recording / reproducing apparatus of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a block diagram showing a schematic configuration of the data recording / reproducing apparatus of the present embodiment. In FIG. 1, reference numeral 1 denotes a recording unit that writes data to a recording medium 2,
2 is a recording medium, 3 is a reproducing unit that reads data from the recording medium 2, and 4 is a position of a succeeding data block based on the data block size in the management information of the data block. This is a search means for searching for a block.

Reference numeral 5 denotes abnormality detecting means for detecting whether reproduced data is reproduced correctly, and reference numeral 6 denotes abnormality detecting means for searching an arbitrary data block according to the type of the data block using the offset value of the offset data block. is there.

In the data recording / reproducing apparatus configured as described above, in order to record the input recording data in data block units, a file is opened and the recording unit 1 is opened.
Through the recording medium 2. At this time, after storing an arbitrary value as the size of the data block management information, the data block is recorded, and after the data block is recorded and the data block size is determined, the data block is moved to the position of the data block management information. Record the actual data block size.

When the recording of an arbitrary data block in the file is completed, the file is closed and the recording on the recording medium 2 is completed. When the size of the data block of the recording data can be known in advance from the size in the memory, the data block size is correctly added from the beginning and recording is performed, so that the feedback processing of the recording unit 1 in FIG. 1 is unnecessary. Become.

Next, when reading a file recorded on the recording medium 2, the file is opened by the reproducing unit 3, and
Read the data block. The normal search means 4 searches for a data block in the file to be read.

Here, in order to reproduce AV data,
Search for the management information data block related to data reproduction, and if found, refer to the data block where AV data is stored from the management information data block,
Play AV data.

At this time, when inconsistency arises in the registration information of the management information data block, such as when the data reproduction time or the offset value to the AV data data block exceeds the data block size of the AV data, or when the reproduction by the user is performed. When there is a request for a data defect, the abnormality detection means 5 detects an abnormality in the reproduced data.

The abnormal time search means 6 uses the offset value from the offset data block in which the offset value from an arbitrary reference position in the file to the data block in the file is stored, and uses the offset value. Access the backup data block of the management information and reproduce the data.

Also in this case, an error occurs if the abnormality detection means 5 detects that the reproduced data is abnormal. If the management information data block relating to the reproduction of AV data and other data blocks are not found in the search by the normal search means 4, the abnormal time detection means 6 uses the offset data block to generate the target data block. Search for.

At this time, when a management information data block relating to the reproduction of AV data is searched, the data block in which the AV data is stored is referred to from the management information data block to reproduce the AV data. Then, in the same manner as described above, the abnormality detection means 5 detects an abnormality in the reproduced data. If a problem occurs, the abnormality detection means 6 again searches the offset data block for the backup data of the AV data management information from the offset data block. Access the block and perform data reproduction.

Further, also in this case, when the abnormality detecting means 5 detects an abnormality in the reproduced data, an error occurs. When the reading from the recording medium 2 is completed, the file is closed.

Here, the process of searching for an arbitrary data block in a file will be described with reference to the flowchart of FIG. First, in step S80, the file is moved to the head position of the file. Then, in step S81, the target data block is searched for up to the position in the file. Therefore, it is determined whether the current position is the position of the target data block. .

If the result of determination in step S81 is that the current position is the target data block, step S8
Proceed to 2 to access the target data block and end. If it is determined in step S81 that the current position is not the target data block, the process proceeds to step S83, where the data block is moved by the size of the data block stored at the head of the current data block, and is moved to the head position of the next data block. .

Then, in step S84, it is determined whether the moved position is the file end position. To determine the end position of the file, the EOF indicating the end position of the file is detected to determine whether the current file position is the end of the file.

If the end position of the file has been reached, it means that the target data block could not be retrieved, and in step S85, an error is output and the processing ends. If the moved position is not the end position of the file, the process returns to step S81 to determine whether the current position is the position of the target data block, and reaches the end position of the file or finds the target data block. Until,
These processes are repeated.

When recording / reproducing using a removable recording medium such as a camcorder using an optical disk,
The recorded data may not be read correctly due to dust or scratches attached to the recording surface. In the case of a stationary device such as a PC, since it is always fixed, it is considered that there is a low possibility that a strong impact is applied to the PC body. In this case, there is a higher possibility that a strong impact such as holding a hand and shooting while running, hitting an object during shooting or inadvertently dropping the device will be applied compared to a stationary device.

In a portable device, in such a use environment, when a shock is applied to the device during recording, the writing laser shifts due to vibration, and the data is mistakenly recorded in another data region. It will be overwritten with wrong data, and when reading the data area, the correct value cannot be read.

As described above, when the data size at the head of the data block becomes unreadable or the correct value cannot be read, the search using the search means 4 includes the following data block including this data block. Cannot be read correctly.

As described above with reference to FIGS. 21 and 22, since the correct data block size cannot be read, the file position moved by the wrong data size from the head address of the data block that cannot be read correctly is moved to the next file position. This is because it is erroneously recognized as the head position of the data block.

Further, the file position in the data block that cannot be read correctly or in the next data block is regarded as the size portion of the next data block, and the reading of the wrong next data size is skipped. Cannot be read.

In the present embodiment, if the data size at the head of the above-mentioned data block cannot be read correctly, it is possible to prevent the subsequent data block from being read correctly. As shown in
At the end of the file, a data block (hereinafter, offset data block) for storing an offset value from a reference position in the file (the beginning or end of the file) to the beginning position of each data block is prepared.

Here, this offset data block is provided at the end of the file. This is because if the management information such as the data size cannot be read correctly, the above-mentioned search means 4 cannot search the offset data block itself, so that the offset data block is surely searched.

That is, a method of seeking to the end position of a file using a seek function of the file system, a method of reading data in a file one after another until EOF which is a file end flag is detected, and the like are used. This makes it easy to move to the end of the file, so that the offset data block can be reliably accessed regardless of whether the data size information cannot be read correctly.

In the above description, the offset data block is registered at the end of the file.
When an offset data block is provided at the beginning of the file, when storing the data block on the recording medium 2, an offset data block containing a temporary value is recorded in advance, and then the data block is stored.

Then, by using a method of updating the offset data block when the offset information for each data block is determined, the offset data block can be provided at the head of the file. As described above, the offset data block does not necessarily need to be placed at the end of the file, and may be provided at an arbitrary fixed position such as the beginning of the file, or may be provided at both the beginning and end of the file.

Next, a method of accessing a data block when an offset data block is set at the end of a file as shown in FIGS. 3 and 4 will be described with reference to the flowchart of FIG.

First, in step S90, in order to access the offset data block at the end of the file storing the offset value from the arbitrary reference position of the file to the data block in the file, the file is moved to the end position of the file. The last field information of the offset data block in which the offset value from the arbitrary reference position of the file to the start position of the offset data block is stored is obtained.

Here, in order to move to the end position of the file, a method of seeking to the end position of the file using the seek function of the file system and the method of seeking the end of the file until the end of file EOF is detected. One possible method is to read data one after another.

Next, in step S91, by moving from an arbitrary reference position to the position of the acquired offset value, the head moves to the head of the offset data block and skips the header information. Then, in step S92, it is determined whether the current field of the offset data block is the field of the offset value of the data to be read.

If the current field is the field of the offset value of the data to be read, step S
Proceed to 93 to acquire the offset value. Then, in step S94, the file is moved from an arbitrary reference position to a position corresponding to the acquired offset value, and step S9 is performed.
In step 5, the data block to be read is accessed.

If the result of determination in step S92 is that the current field is not the field of the offset value of the data to be read, the flow advances to step S96 to move to the next field information.

Then, in step S97, step S
If the position moved at 96 detects EOF indicating the end of the file, the process proceeds to step S98, where the offset value to the data block to be read has not been stored, an error is output, and the process ends.

If the current file position is not the end of the file in step S97, the flow returns to step S92, and the above-described processing is performed until the field of the offset to the data block to be read is found or the end position of the file is reached. repeat.

Next, in the QuickTime file which is one of the AV file formats, any
The processing flow for searching for m will be described with reference to the flowchart in FIG. First, in step S20, the current file position is set at the beginning of the file, and in step S2
In step 1, the atom header, which is 8-byte data, is read from the current file position.

Then, in step S22, it is determined whether the type of the atom of the latter 4 bytes of the read header is the target atom. For example, when searching for a Track header atom that exists in a moov atom and holds information necessary for reproducing voices and images, the ASCII code of the second half of the read header is "tkhd". Is determined.

If it is the target atom, the process proceeds to step S26, accesses the target atom data, and ends. However, if the target atom is not the target atom, the process proceeds to step S23, where the data is skipped from the current position by the data size of the atom, which is the first 4 bytes of the 8 bytes acquired in step S21, and the position after the skip is replaced with the current position. Set to file position.

For example, it is possible to move by seeking from the current position by the size of the atom data using the function of the file system. In step S24, as a result of skipping in step S23, EOF indicating the end position of the file is detected to determine whether the current file position is the end of the file.

If the current file position is at the end of the file, it means that the target atom has not been found in the search file, error processing is performed in step S25, and the search ends.

If the current file position is not at the end of the file, the flow returns to step S21 to read an atom header, which is 8-byte data, from the current file position. Then, the process proceeds to step S22, and the above-described search processing is repeated until the target atom is found in the range up to the end of the file.

In the case of the above-described example of the camcorder,
If the header portion of the atom becomes unreadable, the search means 4 reads incorrect header information and cannot access the atom thereafter.

This is, as described above with reference to FIG.
If the size information of the moov atom cannot be read correctly, moov
Regarding the file position in the middle of the atom as the end position, the next 8 bytes after the end position of the incorrect moov atom
This is for grasping the header area of the mdat atom where V data is recorded.

Therefore, even if the header information of the mdat atom has a correct value, it is impossible to access the mdat atom from the moov atom, so that the subsequent atom cannot be accessed.

As described above, when the incorrect atom header information is read, the correct size and type of the atom cannot be read.
Since the file position moved by the wrong size from the head address of om is misrecognized as the header information of the next atom,
A file position that is not correct header information in that atom or in the next atom is regarded as the header part of the next atom, and the next at
Since the type of om is also erroneously recognized and seek is performed only for the wrong size of the next atom, the data cannot be read even if there is no problem with the subsequent atom data.

A method for detecting that the header information of the read atom is not a correct value will be described. By adding the detection processing of the flowchart shown in FIG. 7 immediately before step S22 in FIG. 6, it is possible to perform a search processing in which the detection that the header information is a correct value is added.

If the size of the atom, which is the first 4 bytes of the acquired atom header information, is larger than the current QuickTime file size or indicates a clearly incorrect value such as a negative value, it is regarded as the correct atom size. In order to determine that the header is not a correct value, in step S50 in FIG. 7, it is determined whether the atom size is larger than 8 which is the header information area size and smaller than the file size.

If the atom size is out of this range, the flow advances to step S52 to perform error processing, and the search ends. In this case, it is possible to recover and access the atom data by performing the later-described atom recovery processing. If the size of the atom indicates a correct value, the process proceeds to step S51, where it is determined whether the type of the subsequent 4 bytes atom is a 4-byte character string that is an ASCII code such as alphabets, numbers, and symbols. Do.

If this condition is not satisfied, it is determined that the header information cannot be read correctly, the flow advances to step S52 to perform error processing, and the search ends. If the condition of step S51 is satisfied and the type of the atom is correct, the header information of the correct atom has been obtained, and the target atom is searched for by performing the processing of step S22 and subsequent steps in FIG.

As described above, when a QuickTime file containing header information that cannot be read correctly is reproduced, a
Since the required atom cannot be found in the tom search or the correct data required for playback cannot be obtained, the playback system generates an error or the playback video or audio malfunctions, causing the user to incorrect AV data. Is being reproduced. In this case, it is possible to recover an atom that cannot be read correctly by selecting a recovery process described later by the user.

As described above, if the atom header information cannot be read correctly, the QuickTime file cannot be reproduced correctly. A method for avoiding this will be described.

When the reproducing system detects that the size of the atom header cannot be read correctly by the detection means 4, the type of the target atom is searched one byte at a time from the beginning of the QuickTime file. Desired atom type
You can search until the ASCII code is found in the file.

However, since the QuickTime files are compared byte by byte, the search speed is low and the efficiency is low. In addition, it is not always possible to search for the type in the header information of the target atom, and it is possible to accidentally search for data having the same ASCII code as the atom type existing in the data area in the atom. Furthermore, if the type of the atom header information cannot be read correctly, the search means is lost.

Therefore, in the present embodiment, the method described below is applied to a QuickTime file. QuickTi
When recording a me file on a recording medium, offset corresponding to the aforementioned offset data block is added at the end of the file.
Records management information called an atom.

The offset atom represents the offset value from the reference address in the file (which may be any position in the file such as the beginning and end of the file or the beginning address of the offset atom) to the starting address of the atom as shown in FIG. It is managed as shown in

In the example of FIG. 8, at is used to manage the offset value.
As om, the size of the offset atom, the type that is the type of the offset atom, the offset value to the moov atom, the offset value to the mdat atom, and the backup moo that is a copy of the moov atom
v Stored in 4-byte units according to the order of the offset values to the atom.

The first field in the header information of the offset atom in FIG. 8 stores the offset value from the reference address in the file to the start address of the moov atom. Similarly, the second field stores the offset value up to the mdat atom. Further, an offset value to the backup moov atom is stored in the third field.

The atoms for managing the offset value are not limited to these atoms, but can be set as needed. A detailed description of the backup moov atom will be described later.

If the size of the atom header information cannot be read correctly, it is impossible to search for further atoms as described above. In search means 4, offset atom
It will no longer be searchable.

Therefore, in order to surely search for an offset atom, the offset atom is assigned to the last atom of the QuickTime file.
Register as This is because it is easy to move to the last position of the file, so that the offset atom can be reliably accessed regardless of the fact that the header information cannot be read correctly.

In the above description, the offset atom is provided at the end of the file.
When an offset atom is provided, when storing the atom data in the recording medium 2, an offset atom containing a temporary value in advance is stored.
And then save the atom data (moov, mdat atom, etc.).

Then, by using a method of updating the offset atom when the offset information to each atom data is determined, the offset atom is added to the head of the file.
Can be provided. Thus, the offset atom
Need not always be at the end of the file, and may be provided at any fixed position such as the beginning of the file, or may be provided at both the beginning and end of the file.

If the header information of the atom cannot be read correctly, the search process of the flowchart shown in FIG. 9 is performed to access the offset atom at the end position of the file in order to search for the target atom.

In step S30, the process moves to the end position of the QuickTime file, and moves from that position to the beginning of the file to the address of 20 bytes which is the size of the offset atom. O when this position has an offset atom
This is the start position of the ffset atom.

Then, in step S31, 8 bytes of header information are obtained from the address. In order to determine whether the acquired header information is a correct offset atom, in step S32, the content of the first 4 bytes of the header information is “20” indicating the size of the offset atom, and the content of the subsequent 4 bytes is offset "ofst" indicating the type of atom
Is determined.

If the header is not the correct offset atom, the flow advances to step S41 to perform error processing, and ends. If the header is a correct offset atom, the process proceeds to step S33. Here, when searching for a moov atom, the process proceeds to step S34, where 8
Move to the byte position, acquire 4-byte data from this position, and proceed to step S39.

In step S33, another atom is deleted.
When searching for, the process proceeds to step S35, where mdat
When searching for an atom, the process proceeds to step S36,
It moves to the position of 12 bytes from the head of t atom, acquires 4-byte data from this position, and proceeds to step S39.

Further, at step S35, another at
When searching for om, the process proceeds to step S37. When searching for a backup moov atom, step S3 is performed.
Then, the process proceeds to step S8, moves to the position of 16 bytes from the head of the offset atom, acquires 4-byte data from this position, and proceeds to step S39.

If another atom is searched in step S37, it means that an attempt has been made to search for atom data that is not registered in the QuickTime file, and the flow advances to step S41 to perform error processing and terminate.

When the process proceeds to step S39 after the processes of steps S34, S36 and S38, the file is moved to an offset position obtained from an arbitrary reference position in the file. Then, in step S40, the target position is
Access atom data.

In the QuickTime File, there is a moov atom that manages the order of reproduction, synchronization control, length, information of each material data, etc. in order to reproduce AV data. The moov atom manages the position and size of data in the mdat atom that stores various AV data collectively.

If the data in the moov atom cannot be read, as in the case where the atom header cannot be read correctly, the data of the moov atom cannot be read correctly. And the offset values representing various material data stored in the mdat atom cannot be correctly grasped, and correct reproduction cannot be performed.

This is because when a removable camcorder using an optical disk is used to shoot an important event or the like,
This occurs when recorded important photographing data cannot be read out due to dust or scratches attached to the recording surface of the disc, or vibration during photographing.

In order to reduce the possibility that such a problem occurs, it is highly necessary to prepare a backup of the management information. Also, original moov atom and backup moo
v If the distance recorded in the recording medium with the atom is short,
If the original moov atom can no longer be read,
There is a high possibility that the backup moov atom cannot be read.

This is because, for example, when an optical disk or the like is damaged by a scratch, if the data size is a small QuickTime file, the original and backup moov atom
Cannot be read out. But,
When the recorded AV data is moving image data such as an MPEG stream, for example, the data size for one hour is about 3.5 Gbytes when the bit rate is 8 Mbps.

As shown in FIG. 10, moov atom, mdat at
om, if recorded in the order of backup moov atom, m
When the size of the dat atom becomes 3.5 GB,
It is unlikely that both the original and backup moov atoms will be damaged.
Even if it is provided in a uickTime file, it is highly likely that it will function as a backup of the original.

As described above, in order to avoid that the reproduction is not performed correctly due to the damage of the moov atom even though the material data and the AV data in the mdat atom are correctly present in the file, FIG. In the example, the mdat atom
Next, a copy of moov atom as a backup, Quick
Add it in the Time file.

By duplicating and registering the management information related to reproduction, even if the original moov atom is damaged, correct reproduction is enabled by accessing the backup moov atom and Moov ato
m can be restored.

However, even if the backup moov atom is recorded, as described above, this backup moov atom
If the size information of the atom cannot be read correctly before accessing m, the backup moov atom cannot be accessed after all.

Thus, as described above, the backup location information of the moov is also registered in the offset atom. When registering the backup moov atom, as shown in FIG. 11, the offset value from an arbitrary reference position in the file to the start position of the backup moov atom is set to the last value of the offset atom shown in FIG. Register in 4 bytes.

As in the case of registering the backup moov atom, even if a file format other than the QuickTime file format is used, if data management information exists, a copy of the management information is used as a backup and the An arbitrary location may be registered, and the location may be managed by information corresponding to an offset atom.

As a method of detecting that the moov atom data is not correct data, there is a method described below, in addition to the method of detecting that the atom header information is not correct. This may be due to detection of the system or by the user.

The result of system detection is moov atom
Of the information managed in,
When the playback time of a certain track is long or when the offset value or size indicating the reference in the mdat atom data exceeds the mdat atom data size, the management information becomes inconsistent and an error occurs from the system. Is the case.

On the other hand, according to the detection by the user, when the user feels a defect in the reproduced video or audio,
It is detected by determining that the QuickTime file is damaged and telling it to the system.

The processing when the above moov atom is detected as not correct data will be described. If the header information of the atom cannot be read correctly, or if the moov atom is detected as not correct data, access the backup moov atom by the above-described search means 6 using the offset atom at the end of the QuickTime file. .

The AV data is reproduced using this as the management information of the AV data. Here, even if the backup moov atom is used, if this management information is detected as not correct data, the mdat atom data cannot be read correctly, or both the original and backup moov atom are not correct data. Conceivable.

When the moov atom is detected as not correct data and a backup moov atom is searched for, the subsequent atom is searched sequentially from the beginning of the file using the atom search method described above with reference to FIG. You may search the QuickTime file until you find a backup moov atom.

When it is detected that the moov atom is not correct data, processing for restoring the moov atom that is not correct data may be performed. This is the backup moov mentioned earlier
Access the atom by searching for the information of the offset atom, and detect whether there is any abnormality in the backup moov atom or play back the AV data with the backup moov atom and confirm that there is no abnormality.

If there is no problem, the location of the abnormal moov atom is searched by the abnormal time searching means 6 based on the offset atom, and the contents of the backup moov atom are copied to the beginning of the moov atom, thereby obtaining the original having the abnormality. No mo
Restore ov atom.

If only the size information of the above atom header cannot be read correctly, the offset value of offsetetatom is used to determine the difference between the offset value of the atom having unreadable header information and the offset value of the subsequent atom. Calculate the size of the atom that has unreadable header information, and
a with header information that tom points to and cannot be read correctly
By writing this size and the type of atom to the head address of tom in 8 bytes, it is possible to recover the header information of atom having header information that cannot be read correctly.

Further, when only the atom type in the atom header is damaged, the position of the atom header is accessed using the offset value of the offset atom, and the atom type of the atom to be searched is replaced with the atom type. Considering the kind, the atom
Writing in the last 4 bytes of the header destroyed
The header information of the atom having the type of atom can be restored.

The method of providing the backup information of the moov atom in the file is not limited to the QuickTime file. If the data is backed up in another file format, the backup of the data is held and the file is stored at the end of the file. By holding the offset value to the backup information, the backup data can be accessed, and the original data can be restored.

As described above, the atoms stored in the QuickTime File are moov atom, mdat atom, backup moov a
There are various types, not just tom. Therefore, instead of the offset information of a fixed number of atoms,
You may want to manage et information.

In the above-mentioned offset atom, since the size of the atom has a fixed length, it is impossible to manage other than the assumed atom. Therefore, offset a recorded at the end of the file
tom is defined as shown in FIG.

The offset atom in this case has an atom size of a variable length, and has, in the field, an offset value from an arbitrary reference position of the file corresponding to the number of atoms registered in the file, following the header area. .

In the example of FIG. 12, after the header information, the offset value to the backup moov atom is included in the field, and after storing the offset value fields to the atoms in some files, the mdat atom, moov atom The offset value of is stored.

Also, some files have offset values to the atoms in the field, and finally, offset ato
Stores the offset value to m itself. In addition, Quick
Since the atom of Time can take the form of nesting, at
An offset value may be registered for an atom inside om.

When all the fields to be registered in the offset atom have been registered, the subsequent 4 bytes (the last 4 bytes of the offset atom. When these 4 bytes have been written, the end of the file becomes the file end) from the reference address to the offset atom Stores the offset value.

As the last four bytes of the offset atom, an atom size, which is the size of the offset atom, may be stored instead of the offset value from the reference address to the offset atom. Using this offset atom, it is possible to register the position information of an arbitrary number of atoms in the file.

Unlike the case of the offset atom which manages the offset information of the determined atom, in the present embodiment, the offset atom
It is impossible to know which atom information is managed by only the t information. The target atom from the offset atom in such a case
The method for accessing the file will be described with reference to the flowchart of FIG. FIG. 13 shows a case where an offset value from a reference address to the offset atom is stored as the last 4 bytes of the offset atom.

In step S60, the file is moved to the end position of the file, and 4-byte data of the end portion of the file is obtained. This value is an offset value from an arbitrary reference position to the start address of the offset atom.

Then, in step S61, by moving to the address of the offset acquired from an arbitrary reference position in the file, it has moved to the head of the offset atom.

In step S62, the header information of the offset which is 8-byte data is obtained from the current address. In step S63, the value of the first 4 bytes of the obtained header information matches the value obtained by subtracting the start position of the offset atom from the file size (the calculated value of the size of the offset atom), and the type of the subsequent 4 bytes is the offset atom Is "ofst" indicating the type of the header, the acquired header information is offset
Judge as an atom.

When the offset atom is not determined,
The process proceeds to step S70, performs error processing, and ends. offs
If it is determined to be et atom, the process proceeds to step S64,
Determine whether the current address is not the end of the field information of the offset atom.

The current address is the last address (offset
If the address is the address at which the offset value to the atom is stored), it means that the target atom has not been found, the process proceeds to step S70, performs error processing, and ends.
If not, the flow advances to step S65 to acquire a 4-byte offset value from the current address, and move from an arbitrary reference position to the address of the offset value.

Next, in step S66, 8-byte header information is obtained from the moved address. Then, in step S67, the last 4 bytes of the header information
The ASCII code is compared to determine whether the type information of the target atom is the type information of the target atom. If the type information is the target atom, the target atom is accessed in step S68, and the processing ends.

If it is not the target atom, step S6
In step 9, add 4 to the current address, move to the position of the field information of the next offset, return to step S64, repeat the above processing until the target atom is found or the end position of the offset atom, and Search for.

Further, in the case of the above search, the original moov
It is sufficient if the type of the atom and the backup moov atom are different names, but otherwise, it becomes indistinguishable, so the offset value of the backup information is offset ato
Make sure to register at any place in m. For example, the offset value to the backup data is stored in the first or last field of the offset atom (see FIGS. 11 and 1).
In 2, it is set in the first field of the offset atom).

Moving to the last position of the file is
Because it is easy, the position where the offset atom is registered is Q
Registering the atom as the last atom in the uickTime file ensures access to the offset atom. However, the offset atom need not be at the end of the file, but may be at any position such as the beginning of the file as long as there is a means for accessing the offset atom. Further, the information may be registered in an arbitrary place, not in the file.

Although the above QuickTime file is an example in which the moov atom that is a backup of the management information is stored in the same file, the backup moov atom may be stored in another file.

When creating a backup of the management information of a QuickTime file (hereinafter referred to as a “moov atom backup”) in which moving images and still images are recorded in an external QuickTime file, the backup of the moov atom is stored at an arbitrary position in the original QuickTime file. The location (path) of the external QuickTime file in which the data is stored and the optr atom (corresponding to the external reference data block) holding the file name are recorded.

In this case, as shown in FIG. 14, the optr atom has an atom size in the first 4 bytes and an atom size in the next 4 bytes.
Record atom header as m type. The following field is a Poi indicating the location of the moov atom backup data.
In the nt field, the QuickTime file name storing the backup data of the moov atom is recorded as an external file name including the path. Then, in the last field, the Poin in the optr atom from the end position of the optr atom
Stores the offset value to the t field.

FIG. 15 shows an example of a QuickTime file using the optr atom. In FIG. 15, the original
An optr in which the QuickTime file is recorded in the order of moov atom and mdat atom, and stores the file name of the external QuickTime file that stores the backup of the moov atom
atom is recorded at the end of the file. This FIG.
Is the QuickT pointed to by the Point field in the optr atom
This is an example in which only the backup of the moov atom is recorded in the ime file, and a plurality of other atoms may be recorded in the QuickTime file having the file name stored in the Point field.

A method of accessing the backup of the moov atom using the above optr atom will be described. Original
If access to the moov atom becomes impossible, seek to the file end and then file end (optr atom
By using the offset value to the Point field in the optr atom in the 4 bytes of (end), the Point field is accessed, and the QuickTime file name in which the backup of the moov atom is registered is obtained.

Then, the file having the obtained file name is opened, and the external QuickT
Search for moov atom in ime file. Thus, mo
By accessing the backup data of the ov atom, it is possible to reproduce the AV data. Also,
As described above, by copying the backup data of the moov atom to the original moov atom, the moo file in the original QuickTime
v It is also possible to recover the atom.

Further, the backup of the moov atom existing outside need not be recorded in the QuickTime file format, but may be recorded in any data format. In this case, the backup of the external moov atom is accessed using the optr atom as shown in FIG.

In FIG. 16, the first four bytes contain atom
In the next 4 bytes of size, an atom header is recorded as an atom type. Next, from the arbitrarily defined reference position in the data in which the backup of the moov atom is stored,
Point which is the offset value to the backup data of tom
Stores the Offset field. In the parentheses in the figure, m
The file stores the backup data of the oov atom, and is an offset value from the reference position in this file.

The next succeeding field is a Point field indicating the location of the backup data of the moov atom. In this case as well, the parentheses in the figure indicate that the data storing the backup of the moov atom is a file, and the file name storing the backup data of the moov atom is recorded as an external file name. And in the last field, optr atom end from optr
Store the offset value to Point Offset field in atom.

When a backup of such a moov atom exists in an external file, QuickTi using the optr atom is used.
FIG. 17 shows an example of the me file. In FIG. 17, the original QuickTime files are moov atom, mdat atom
The file name of the external file that stores the backup of the moov atom and the optr atom that stores the offset value to the backup data of the moov atom in the external file are recorded at the end of the file. I have.

This optr atom is a file end (optr atom)
The 4-byte offset value of the atom end) is Poi in the optr atom
nt Offset field, this Point Offset
The field points to the moov atom backup data part in the external file. The subsequent Point field points to the external file. FIG. 17 is an example in which a backup of the moov atom is recorded at the offset value position of the Point Offset field in the file (external file) pointed to by the Point field in the optr atom. May be recorded with other data.

An access method when backup data of a moov atom exists in the above-mentioned external data will be described. If access to the original moov atom becomes impossible, seek to the file end and then optr at in the 4 bytes of the file end (optr atom end)
By accessing the Point Offset field by the offset value to the Point Offset field in om, Point
Get the value of Offset.

Then, the next Point field is accessed to obtain the location (for example, an external file name) of the data in which the backup of the moov atom is registered. Further, the data at the position of the read Point Offset in the obtained location data (external file) is accessed, and the backup data of the moov atom is obtained.

As described above, by accessing the backup data of the moov atom, it is possible to reproduce the AV data. Also, as described above, moov a
By copying the backup data of tom to the original moov atom, the original
Moov atoms in QuickTime files can be recovered.

The optrato shown in FIG. 14 to FIG.
m is only required to record the location of the backup data of the moov atom, and is not limited to the external reference file name. For example, if a moov atom backup is stored in memory, the address where the data exists may be stored, and if it exists on a network,
Just record the URL to that data. That is, optr at
In om, the location of the location where the backup data of the moov atom exists may be recorded.

In the Point field of the above optr atom, not only the location of the moov atom in the backup information but also the location of an arbitrary atom such as the mdat atom stored in another file may be stored. .

Further, one atom in one external data
Instead of referencing only, a plurality of atoms in a plurality of external data may be referenced. In this case, the optr atom is a set of the location (for example, a file name) indicating the external data and the offset value from a predetermined reference position in the external data to the atom to be referred to, and this set is used as many as necessary. You just need to register.

The external data reference (for example, moov ato
m backup data) is not limited to QuickTime files, but can also be applied to the aforementioned data blocks that record the data size at the beginning of the data.
By preparing an external reference data block storing the location of the data to be referenced in the original file, external data can be accessed.

As described in detail above, when one or more data blocks obtained by adding management information indicating the size of data to a certain set of data are recorded in the file on the recording medium, If the management information of any data block becomes unreadable, the subsequent data block cannot be accessed.

Therefore, in the data recording / reproducing apparatus of the present embodiment, the offset value from an arbitrary reference position in the file for accessing each data block is set at the last position in the file that can be securely accessed. An offset data block to be registered, or an external reference data block that holds necessary backup data in data different from this file (for example, an external file) and registers the location of another data having the backup data Is provided, it is possible to reliably access all the data blocks and the backup of the data blocks, and it is possible to solve the problem that the data blocks subsequent to the unreadable data blocks cannot be accessed.

In the QuickTime file, if the data in the moov atom that manages the recording / reproduction of AV data becomes unreadable, the AV data cannot be recorded / reproduced correctly.

For this purpose, this problem can be solved by providing a copy of the moov atom as a backup moov atom in the file. However, similar to the above, the header information of the atom existing up to the backup moov atom can be solved. Becomes unreadable, backup moov ato
You cannot access m.

For this reason, in the data recording / reproducing apparatus of the present embodiment, an offset atom for registering an offset value from an arbitrary reference position in a file for accessing a backup moov atom is provided, or this QuickTi
An op that stores a backup of the moov atom in external data separate from the me file and registers the location of this external data
By providing tr atom, backup moov is sure
It becomes possible to access the atom, and it is possible to suppress a problem that a problem occurs in recording / reproducing AV data.

The present invention can be applied to a file format other than the QuickTime file by providing a data area representing an offset at the end of the file or at an arbitrary position. The offset value to the data area representing the offset May be stored at any location in the file.

Also, in a file format other than the QuickTime file, if a backup of the management information of the AV data is registered, the data area indicating the offset and the area indicating the location of the external data in which the backup is registered are read from the data area. Obviously, the management information of the original AV data can be restored, and the management information (data length and type) of the data block can be restored using the data representing the offset.

[0167]

According to the present invention, an offset data block in which an offset value from an arbitrary reference position in a file for accessing each data block is registered is provided. Can be accessed, and a data block subsequent to the data block that has become unreadable can be accessed.

A copy of the data block of the management information of the AV data is provided in the file as a backup data block, and an offset value in which an offset value from an arbitrary reference position in the file to the head position of the backup data block is registered. By providing a data block or providing this backup data block in external data separate from this file and providing a data block indicating the location of this external data,
It is possible to reliably access the backup data block of the management information of the AV data, and it is possible to avoid a problem in recording / reproducing the AV data.

Further, if the management information data block of the original AV data is detected to be damaged, the management information data block of the backup AV data is copied to the original management information data block, thereby obtaining the damaged AV data. The management information data block can be recovered. Further, even when the management information of the data block is detected to be damaged, the management information of the damaged data block can be restored using the offset value of the offset data block.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a data recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a search process of an arbitrary data block in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 3 is a schematic explanatory diagram showing a case where an offset data block is recorded at the end of a file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 4 is a schematic explanatory diagram showing a case where an offset data block is recorded at the end of a file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 5 is a flowchart showing a search process of an arbitrary data block using an offset data block in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 6 is a flowchart showing a process of searching for arbitrary atom data in a QuickTime file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 7 is a flowchart showing a process of detecting whether or not the header information of the read atom of the QuickTime file is a correct value in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 8 is a schematic explanatory diagram showing a fixed-length offset atom in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 9 is a flowchart showing a process of searching for arbitrary atom data when an offset atom has a fixed length in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 10 is a schematic explanatory diagram showing a case where a fixed-length offset atom is recorded at the end of a file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 11 is a schematic explanatory diagram showing a case where a variable-length offset atom is recorded at the end of a file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 12 is a schematic explanatory view showing a variable length offset atom in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 13 is a flowchart showing a process of searching for arbitrary atom data when an offset atom has a variable length in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 14 is a schematic explanatory diagram showing an optr atom indicating an external QuickTime file name in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 15 is a schematic explanatory diagram showing a case where an optr atom indicating an external QuickTime file name is recorded at the end of a file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 16 is a schematic explanatory diagram showing an external file name and an optr atom indicating an offset value in the file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 17 is a schematic explanatory diagram showing a case where an external file name and an optr atom indicating an offset value in the file are recorded at the end of the file in the embodiment of the data recording / reproducing apparatus of the present invention.

FIG. 18 is a schematic explanatory diagram showing a case where a plurality of data blocks including a plurality of entries and including management information indicating the number of the entries are recorded in a file.

FIG. 19 is a schematic explanatory diagram showing a case where a plurality of data blocks including image data and management information indicating the size thereof are recorded in a file.

FIG. 20 is a schematic explanatory diagram showing the structure of atom data in a QuickTime file.

FIG. 21 is a schematic explanatory view showing that when management information of a certain data block in FIG. 18 cannot be read, access to a subsequent data block becomes impossible.

FIG. 22 is a schematic explanatory view showing that when management information of a certain data block in FIG. 19 cannot be read, access to a subsequent data block becomes impossible.

FIG. 23 is a schematic explanatory diagram showing that when header information of atom data in a QuickTime file becomes unreadable, subsequent atom data cannot be accessed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording part 2 Recording medium 3 Reproduction part 4 Normal search means 5 Reproduction data abnormality detection means 6 Abnormality retrieval means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B082 DE06 EA01 EA05 5D044 AB01 AB05 AB07 DE03 DE38 DE62 DE64 EF05 FG19 5D110 AA27 AA29 DA06 DA07 DA11 DB03 DC05 DC16 DC16

Claims (12)

[Claims] A recording unit for recording, on a recording medium, a file in which various data are registered in units of a data block including data and management information including a size, a number, and a type of the data; Based on the data size in the data block, obtains the start position of the subsequent data block, and reads out the subsequent data block.Based on the data type in the management information in the data block read out by the reproduction unit, the file A data recording / reproducing apparatus provided with a normal search means for searching for a data block in a file, wherein an offset value from an arbitrary reference position in the file to a head position of some data blocks included in the file is registered. Characterized in that the offset data block is registered at an arbitrary position in the file. Raw equipment. 2. The data recording / reproducing apparatus according to claim 1, wherein the size of the offset data block is a fixed length. 3. The data recording / reproducing apparatus according to claim 1, wherein the size of the offset data block is variable. 4. The data recording / reproducing apparatus according to claim 1, wherein the data block includes a data block in which AV data is registered and a data block of the data block of the AV data.
A data block in which management information for managing a reproduction mode is registered. 5. The data recording / reproducing apparatus according to claim 4, wherein a copy of the data block in which the management information of the AV data is registered is registered in a file as a backup, and an arbitrary reference in the file is registered. A data recording / reproducing apparatus, wherein an offset value from a position to a backup data block of the management information is registered in the offset data block. 6. The data recording / reproducing apparatus according to claim 1, wherein an abnormality detecting unit that detects an abnormality of the reproduced data read by the reproducing unit, and the reproduced data is read by the abnormality detecting unit. A data recording / reproducing apparatus comprising: an abnormal time search means for searching an arbitrary data block based on the offset value registered in the offset data block when the abnormality is detected. 7. The data recording / reproducing apparatus according to claim 6, wherein the abnormality detecting means detects an abnormality in an original data block in which AV data management information is registered by the abnormality detecting means. At this time, a backup data block in which the management information of the AV data is registered is searched based on the offset value registered in the offset data block, and the AV data is reproduced based on the backup data block of the management information. A data recording / reproducing apparatus characterized in that: 8. The data recording / reproducing apparatus according to claim 7, wherein the management information of the AV data in which the abnormality is detected is registered using a backup data block in which the management information of the AV data is registered. A data recording / reproducing apparatus for recovering an original data block that has been set. 9. The data recording / reproducing apparatus according to claim 6, wherein said abnormal time searching means is configured to detect said offset when said abnormality detecting means detects an abnormality in data block management information. A data recording / reproducing apparatus for recovering management information of a data block in which the abnormality is detected, using an offset value registered in the data block. 10. Data, the size and number of the data,
Recording means for recording, on a recording medium, a file in which various data are registered in units of data blocks comprising management information including a type; and a head position of a subsequent data block based on a data size in the management information in the data block. And a reproducing means for reading out a subsequent data block, and a normal search means for searching for a data block in a file based on a data type in management information in the data block read by the reproducing means. In the data recording / reproducing apparatus, an external reference data block in which the location of data existing outside the file is registered is registered at an arbitrary position in the file. 11. The data recording / reproducing apparatus according to claim 10, wherein the data block includes a data block in which AV data is registered and a data block of the AV data.
A data block in which management information for managing a reproduction mode is registered. 12. The data recording / reproducing apparatus according to claim 11, wherein a copy of a data block in which the management information of the AV data is registered is registered outside the file as a backup, and the backup of the management information is A data recording / reproducing apparatus, wherein the location of a data block is registered in the external reference data block.