JP4706530B2 - Playback apparatus, playback method, and playback program - Google Patents

Description

  The present invention relates to a playback apparatus, a playback method, and a playback program capable of efficiently performing random access to digital video data recorded on a recording medium, and in particular, the amount of information for each frame varies.

  2. Description of the Related Art A data recording / reproducing apparatus that records digital video data and digital audio data on a recording medium and reproduces the data from the recording medium is known. In recent years, as a recording medium for recording digital video data and digital audio data, a randomly accessible recording medium such as an optical disk, a hard disk, or a semiconductor memory is often used for recording and reproducing digital video data and digital audio data. It is getting to be.

  Since digital video data has a huge data capacity, it is generally compressed and encoded by a predetermined method and recorded on a recording medium. In recent years, MPEG2 (Moving Picture Experts Group 2) system is known as a standard system for compression coding. In MPEG2, digital video data is compression-encoded using DCT (Discrete Cosine Transform) and motion compensation, and further, a data compression rate is increased using a variable-length code. In the MPEG2 system, since a variable length code is used, the data size for each frame is generally not constant.

  Here, for example, consider a case where digital video data imaged and output by an imaging device is recorded on a disk-shaped recording medium such as an optical disk, which has a relatively slow access speed compared to a hard disk drive or the like. When digital video data that has been captured and output in real time is compressed and encoded and recorded on a recording medium, continuous data on the recording medium is addressed in order to prevent data loss. It is possible to write in

As an example, digital video data is continuously written on a recording medium in a relatively long time unit such as every clip or every predetermined reproduction time. In Patent Document 1, digital video data and digital audio data corresponding to a playback time zone are alternately arranged for each predetermined playback time unit having a data size of one track or more, for example, about 2 seconds. A recording apparatus for recording is described.
JP 2004-310831 A

  By the way, when editing digital video data recorded on a recording medium in this way, it is necessary to be able to access the digital video data on the recording medium in units of frames. When the digital video data recorded on the recording medium is compression-encoded by a method having a different data size for each frame, such as the MPEG2 method described above, the head position of each frame on the recording medium can be specified. It is necessary to keep.

  MXF (Material Exchange Format) is an example of a format that can improve the accessibility and operability of digital video data recorded on a recording medium such as an optical disk. An MXF file defined by MXF is a file that is a combination of digital video data recorded on an optical disc and an index table including access information for the digital video data, and uses the index table in the MXF file. Thus, the frame boundary of the digital video data can be indicated. By using this index table, the digital video data on the optical disc can be randomly accessed in units of frames.

  More specifically, when a certain position of the digital video data on the optical disc is accessed, information on the frame boundary in the vicinity of the accessed portion is collected, and an index table is created based on the collected information. The created index table is cached on the memory of the device, for example. When a seek operation is performed on the optical disk and another position of the digital video data on the optical disk is accessed, the already cached index table is discarded, and the vicinity of the position accessed by the seek operation is again displayed. Frame boundary information is collected and an index table is created.

  Conventionally, since this index table is created every time a seek operation is performed on an optical disc, for example, a waiting time for creating the index table occurs for each seek operation, and random accessibility and operability are impaired. There was a problem that it was.

  In particular, for digital video data having a different data size for each frame, such as the above-described MPEG2, the index table information indicating the frame boundary is calculated to construct the table, which is very heavy on the apparatus. There was a problem of processing.

  Accordingly, an object of the present invention is to provide a playback apparatus, a playback method, and a playback program capable of efficiently performing random access processing on digital video data recorded on a recording medium and having different data sizes for each frame. is there.

In order to solve the above-described problems, the present invention includes a storage unit and an index table creation unit, and the storage unit closes an index table created by the index table creation unit to a clip recorded on a recording medium. The index table creation unit creates an index table composed of management information of a plurality of frames of a clip based on information on the recording medium when an output frame is designated, and then outputs it. When the frame is specified, if the information of the edit unit corresponding to the specified frame is not described in the index table, an index table for managing the edit unit is further created. Device.

The present invention also includes an index table creation step for creating an index table comprising management information for a plurality of frames of a clip based on information on a recording medium when an output frame is designated, and an index table creation step. A step of temporarily storing an index table to be created in a storage unit until a clip recorded on a recording medium is closed , and the next time an output frame is designated, it corresponds to the designated frame If the information of the edit unit to be edited is not described in the index table, an index table for managing the edit unit is further created.

The present invention also includes an index table creation step for creating an index table comprising management information for a plurality of frames of a clip based on information on a recording medium when an output frame is designated, and an index table creation step. A step of temporarily storing an index table to be created in a storage unit until a clip recorded on a recording medium is closed , and the next time an output frame is designated, it corresponds to the designated frame If the information of the edit unit to be edited is not described in the index table, the reproduction program causes the computer apparatus to execute a reproduction method for further creating an index table for managing the edit unit .

As described above, according to the present invention, when an output frame is specified, an index table including management information of a plurality of frames in a clip recorded on a recording medium is created based on the information on the recording medium. When the output frame is designated in the table, if the information of the edit unit corresponding to the designated frame is not described in the index table, an index table for managing the edit unit is further created and stored in the storage unit. Since the data is stored, there is an effect that the process of creating the index table can be performed efficiently.

  Further, by accessing the frames in the clip recorded on the recording medium via the index table, there is an effect that the random access to the clip is speeded up.

  The first embodiment of the present invention will be described below. Prior to the first embodiment of the present invention, in order to facilitate understanding, the MPEG2 system, which is a compression encoding system for digital video data applicable to the present invention, will be schematically described.

  The data stream structure of MPEG2 will be schematically described. MPEG2 is a combination of motion compensation predictive coding and compression coding by DCT. The data structure of MPEG2 has a hierarchical structure, and from the lower order is a block layer, a macroblock layer, a slice layer, a picture layer, a GOP layer, and a sequence layer. The block layer is composed of DCT blocks that are units for performing DCT. The macroblock layer is composed of a plurality of DCT blocks. The slice layer is composed of a header part and one or more macroblocks. The picture layer is composed of a header part and one or more slices. A picture corresponds to one screen. The boundary of each layer can be identified by a predetermined identification code.

The GOP layer includes a header part, an I (Intra-coded) picture that is a picture based on intra-frame coding, a P (Predictive-coded) picture that is a picture based on predictive coding , and B (Bi-directionally predictive coded). ) Picture. The I picture can be decoded only by its own information, and the P and B pictures require the previous or previous image as a reference image and are not decoded alone. For example, a P picture is decoded using an I picture or a P picture temporally prior to itself as a reference image. In addition, the B picture is decoded using two pictures, an I picture or a P picture before and after itself, as reference pictures. A group completed by itself including at least one I picture is called GOP (Group Of Picture), and is the smallest unit that can be independently accessed in an MPEG stream.

  A GOP is composed of one or more pictures. Hereinafter, for convenience, a GOP composed of only one I picture will be referred to as a single GOP, and a GOP composed of a plurality of pictures composed of an I picture and P and / or B pictures will be referred to as a long GOP. To do. In the single GOP, by configuring the GOP only from the I picture, editing in units of frames is facilitated, and since the predictive coding between frames is not performed, higher image quality can be obtained. On the other hand, long GOP has the advantage of good compression efficiency because it performs predictive coding between frames.

  In a long GOP, a closed GOP having a GOP-closed structure that can be completely decoded within the GOP, and an open GOP that can use the information of the previous GOP in the encoding order at the time of decoding There are two types. An open GOP can be decoded using more information than a closed GOP, so that a high image quality can be obtained and is generally used.

  Conventionally, a DV format having a bit rate of 25 Mbps (megabit second) is known as a video signal format. Particularly in video equipment used in broadcasting stations and the like, a DV format video signal is used in the above-mentioned single GOP to realize a high image quality and a highly accurate editing environment.

  On the other hand, in recent years, with the implementation of digital high-definition broadcasting and the like, the HD (High Definition) format, which has a higher resolution than the SD format, has come to be used. The HD format has a high bit rate with high resolution, and a single GOP cannot record for a long time on a recording medium. Therefore, it is common to use an HD format video signal after being compressed with the above-mentioned long GOP.

Decoding processing in the case of a long GOP will be described with reference to FIG. Here, it is assumed that 1 GOP is an open GOP and is composed of a total of 15 pictures, one I picture, four P pictures, and 10 B pictures. The display order of the I, P, and B pictures in the GOP is “B ₀ B ₁ I ₂ B ₃ B ₄ P ₅ B ₆ B ₇ P ₈ B ₉ B ₁₀ P ₁₁ B as shown in FIG. 1A as an example. is as ₁₂ B ₁₃ P ₁₄ ". The subscript indicates the display order.

In this example, the first two B ₀ and B ₁ pictures are predicted and decoded using the last P ₁₄ picture in the previous GOP and the I ₂ picture in this GOP. . The first P ₅ picture in the GOP is a picture predicted and decoded from the I ₂ picture. Other P ₈ picture, P ₁₁ picture and P ₁₄ are pictures decoded is predicted by using the preceding P-picture, respectively. Each B picture after the I picture is a picture predicted and decoded from the preceding and following I and / or P pictures.

  On the other hand, since B pictures are predicted and decoded using temporally preceding and following I or P pictures, the arrangement order of I, P, and B pictures on a stream or recording medium takes into account the decoding order in the decoder. It is necessary to decide. That is, an I and / or P picture for decoding a B picture must always be decoded before the B picture.

In the above example, the arrangement of each picture on the stream or the recording medium is “I ₂ B ₀ B ₁ P ₅ B ₃ B ₄ P ₈ B ₆ B ₇ P ₁₁ B ₉ B as illustrated in FIG. 1B. ₁₀ P ₁₄ B ₁₂ B ₁₃ ”and are input to the decoder in this order. The subscripts correspond to FIG. 1A and indicate the display order.

In the decoding process in the decoder, as shown in FIG. 1C, the I ₂ picture is first decoded, and the decoded I ₂ picture and the last P ₁₄ picture in the previous GOP (display order) are B _0. Predict and decode pictures and B ₁ pictures. Then, the B ₀ picture and the B ₁ picture are output from the decoder in the order of decoding, and then the I ₂ picture is output. Once the B ₁ picture is output, the P ₅ picture is then predicted and decoded using the I ₂ picture. Then, the B ₃ picture and the B ₄ picture are predicted and decoded using the I ₂ picture and the P ₅ picture. The decoded B ₃ picture and B ₄ picture are output from the decoder in the order of decoding, and then the P ₅ picture is output.

  Hereinafter, similarly, the P or I picture used for prediction of the B picture is decoded before the B picture, the B picture is predicted and decoded using the decoded P or I picture, and the decoded B picture is decoded. Is output, the process of outputting the P or I picture used to decode the B picture is repeated. A picture arrangement as shown in FIG. 1B on a recording medium or in a stream is generally used.

Next, a data structure applicable to the first embodiment of the present invention will be described. 2 to 5 show a mapping structure for an MPEG (Moving Pictures Experts Group) stream of a data format called MXF (Material Exchange Format), which can be applied to the first embodiment of the present invention. MXF is a file format standard defined by SMPTE (Society of Motion Picture and Television Engineers), and a mapping structure for an MPEG stream described below is defined by SMPTE-381M. Hereinafter, according to the MXF provisions such as SMPTE-381m, an example of a file having a structure in which video data and audio data are frame-interleaved, it referred to as interleaved MXF file.

  As shown in FIG. 2A, the interleaved MXF file generally includes a file header, a file body, and a file footer. The file header includes a header partition pack (HPP) and header metadata. The header partition pack stores data for specifying the header, the format of data arranged in the file body, information representing the file format, and the like. The header metadata stores, for example, file unit metadata such as information on the creation date and time of the file and information on data arranged in the file body.

  The file body includes a body partition pack (BPP), an edit unit (Edit Unit), and an index table (Index Table). The body partition pack stores data for specifying the body. An index table of 0 or 1 and one or a plurality of edit units are arranged in an area delimited by the body partition pack. The edit unit stores data for each frame. The index table stores information for each edit unit included in the previous area divided by the body partition pack. Details of the edit unit and the index table will be described later.

  The file footer includes a footer partition pack, an index table, and a random index pack. Since there is no portion directly related to the present invention regarding the file footer, the description thereof will be omitted to avoid complexity.

  An assembly of edit units for each region divided by the body partition pack is called an essence container (see the left side of FIG. 2B). That is, the essence container corresponds to video and audio data that are actually reproduced based on the interleaved MXF file.

  A collection of index table segments arranged in the file body and the file footer is called an index table (see the right side of FIG. 2B). For example, when the interleaved MXF file is read by the system, each index table segment is searched and read out, and an index table is constructed, so that information on all edit units in the interleaved MXF file is constructed. It can be obtained by referring to the table.

  FIG. 2C shows an exemplary structure of the index table. In FIG. 2C, the numbers written at the bottom of each area indicate the size of the area in bytes. The index table is encoded using a KLV (Key-Length-Value) code. In the KLV code, the “K (Key)” portion is an identifier indicating a data item that is KLV encoded in accordance with SMPTE 335M / RP210A, and has a data length of 16 bytes. The “L (Length)” portion has a data length of 4 bytes, and represents the data length following the “L” portion in bytes. The “V (Value)” part is an area in which the data body is stored. In addition, a structure consisting of a “T (Local Tag)” portion and an “L (Length)” portion, each having a data length of 2 bytes, and a variable length data portion is further defined inside the “V” portion. Can do.

  At the head of the index table, an index table segment key having a data length of 16 bytes is arranged. Subsequently, after an “L” portion is arranged with a data length of 4 bytes, and an “T” portion and an “L” portion each having a data length of 2 bytes, an instance ID (Instance ID) having a data length of 16 bytes is placed. ) Is placed. The instance ID is described using a UUID (Universally Unique ID). Subsequently, a “T” portion and an “L” portion are arranged, and then an index edit rate (Index Edit Rate) is arranged with a data length of 8 bytes. The index edit rate indicates whether the frame rate of the video data is 29.97 Hz, 25 Hz, or 23.98 Hz.

  Subsequently, a “T” portion and an “L” portion are arranged, and then an index start position (Index Start Position) is arranged with a data length of 8 bytes. The index start position indicates the head number of the edit unit managed by this index table. Subsequently, a “T” portion and an “L” portion are arranged, and then an index duration (Index Duration) is arranged with a data length of 8 bytes. In the index duration, the length of the entire edit unit managed by the index table segment is indicated by the number of edit units.

  Subsequently, a “T” portion and an “L” portion are arranged, and thereafter an edit unit byte count is arranged with a data length of 4 bytes. The edit unit byte count describes the data length of the video frame if the video frame has a fixed length, and describes the value “0” if the video frame has a variable length. Subsequently, a “T” part and an “L” part are arranged, and thereafter an index SID is arranged with a data length of 4 bytes, and a body SID is arranged after the “T” part and the “L” part. . These index SID and body SID are fixed values having values “1” and “2”, respectively. Subsequently, a “T” portion and an “L” portion are arranged, and then a slice count (Slice Count) is arranged with a data length of 1 byte. The slice count indicates a slice (described later) managed by this index table.

  Subsequently, a “T” portion and an “L” portion are arranged, and then a delta entry array (Delta Entry Array) having a data length of 44 bytes is arranged. Subsequently, a “T” portion and an “L” portion are arranged, and thereafter an index entry array (Index Entry Array) having a variable length is arranged. The delta entry array and index entry array will be described later.

  The “K” portion, the “L” portion, and the filler portion are arranged behind the index entry array. The filler part is provided to align the size of the index table to a predetermined value.

  FIG. 3 shows an example of an edit unit and a delta entry array. The index table shown in FIG. 3C is the same as FIG. The edit unit is composed of data for one frame, and includes system data, MPEG video data, and audio data (AES) elements as shown in FIG. 3A as an example. The system data and the audio data elements for four channels have a fixed length (CBE: Constant Bytes per Element), and the video data elements have a variable length (VBE: Variable Bytes per Element). Within one edit unit, a slice is cut for each variable length data element. In the example of FIG. 3A, since the video data element has a variable length, the slice is cut at the rear end of the video data element, the first half is slice 0, and the second half is slice 1. In the above slice count, (number of slices-1) is described.

  In the delta entry array, as shown in an example in FIG. 3B, offset information in the edit unit of each data included in the edit unit is described. In the delta entry array, information for each data element included in the edit unit is referred to as a delta entry. The delta entry array is a set of delta entries of each data element included in the edit unit. At the head of the delta entry, a number of delta entries having a data length of 4 bytes is arranged. In this example, the edit unit consists of six data elements, one system data element, one video data element, and four audio data elements. The delta entry array includes six delta entries, and the number of delta entries. Describes the value “6”. After the number of delta entries, a delta entry length (Length of Delta Entries) indicating the data length of the delta entry in bytes is arranged.

  Each delta entry includes a pos table index, a slice, and an element delta. The post table index takes the value “−1” when the data display order and the encoding order are different for each element, and the difference is determined by the temporal offset value in the index entry array. When the encoding order matches, the value “0” is taken. If the display order and the encoding order differ for each part of the element data, the difference for each part is described in the post table in the index entry array, and the value of the post table index describes the difference. Takes the index value (positive value) of the table. Since the post table index is not related to the present invention, further explanation is omitted. The slice indicates the slice position within the edit unit of the corresponding data. The element delta indicates an offset from the top of the slice.

  FIG. 4 shows an example of an index entry array and an essence container stream. 4A and 4B show an example of a data stream by an essence container, that is, an essence container stream. A stream is formed as an aggregate of edit units of an interleaved MXF file.

  FIG. 4C shows an example of an index entry array. The number of index entries indicates the number of index entries included in the index entry array. Since each index entry corresponds to an edit unit, the number of index entries indicates, in other words, the number of edit units managed by this index table segment. An index entry length (Length of Index Entries) indicating the data length of the index entry in bytes is arranged after the number of index entries.

  Each index entry includes a temporal offset, a key-frame offset, a flag, a stream offset, and a slice offset. The temporal offset has a data length of 1 byte and indicates information on rearrangement of the display order and the encoding order. The key frame offset has a data length of 1 byte and indicates position information of a key frame used for decoding. The flag has a data length of 1 byte and indicates the frame type. Details of the temporal offset, key frame offset, and flag will be described later. The stream offset has a data length of 8 bytes and indicates an offset with respect to the head of the essence container stream of the entire interleaved MXF file. The slice offset has a data length of 4 bytes, and indicates an offset of slice 1 in the corresponding edit unit.

  The temporal offset, key frame offset, and flag described above will be described in more detail with reference to FIG. FIG. 5A shows a frame display order (display order), and FIG. 5B shows a frame coding order (coding order) in units of edit units. In FIG. 5A and FIG. 5B, display orders and coding orders corresponding to a certain index table are shown with numbers assigned in order starting from # 0. FIG. 5C shows temporal offsets, key frame offsets and flags corresponding to the display order of FIG. 5A and the coding order of FIG. 5B.

  “I”, “P”, and “B” shown in FIGS. 5A and 5B indicate an I picture, a P picture, and a B picture, respectively. In the display order, a frame obtained by decoding the I picture is described as a frame “I”, and in the coding order, an edit unit in which the I picture is stored is described as an edit unit “I”.

  In the example of FIG. 5, for explanation, one GOP is composed of one I picture, one P picture, and four B pictures. A GOP consisting of the first six pictures is a closed GOP, and a GOP consisting of the second six pictures is an open GOP. Also, the display order and coding order corresponding to a certain index table are shown by numbering sequentially from # 0.

  As described above, in the closed GOP, decoding is completed within the GOP. Therefore, in the case of the configuration shown in FIG. 5, the frame “B” # 0 and the frame “B” # 1 in the display order include the frame “ I "# 2 is decoded only. Also, frame “B” # 3 and frame “B” # 4 are decoded using frame “I” # 2 and frame “P” # 5.

  On the other hand, in open GOP, it is possible to perform decoding using a picture of the previous GOP. In the example shown in FIG. 5, frame “B” # 6 and frame “B” # 7 use frame “I” # 8 and frame “P” # 5 included in the previous GOP, respectively. Decrypted. At this time, since the frame “P” # 5 is decoded using the frame “I” # 2, in order to decode the frame “B” # 6 and the frame “B” # 7, the frame “I” "# 8", frame "P" # 5 and frame "I" # 2 are required.

  The temporal offset indicates how many frames the coding order has been rearranged with respect to the display order. For example, since the frame “I” # 2 located third in the display order corresponds to the edit unit “I” # 0 located first in the coding order, the temporal offset value is “−2”. Further, the frame “B” # 6 located at the seventh position in the display order corresponds to the edit unit “B” # 7 located at the eighth position in the coding order, and therefore the value of the temporal offset is “+1”.

  The key frame offset indicates the number of edit units that need to be traced in order to decode the video data included in the corresponding edit unit. For example, since the edit unit # 0 including the frame “I” # 2 can decrypt the frame “I” # 2 by itself, the value of the key frame offset is “0”. The edit unit # 4 including the frame “B” # 3 requires the frame “I” # 2 and the frame “P” # 5 in order to decode the frame “B” # 3, and the frame “I”. It is necessary to go back to edit unit # 0 including # 2. Therefore, the key frame offset value of edit unit # 4 is “−4”.

Further, in the case of an open GOP, the first frame “B” is decoded using the frame of the previous GOP. For example, the frame “B” # 7 is decoded using the frame “I” # 8 and the frame “P” # 5 of the previous GOP, and the frame “P” # 5 further includes the frame “I”. Decoded using # 2. Therefore, edit unit # 8 including frame “B” # 7 needs to be traced back to edit unit # 0 including frame “I” # 2. Therefore, the key frame offset value of edit unit # 8 is “−8”.

  The flag has a data length of 1 byte, that is, 8 bits, and predetermined information related to the edit unit corresponding to the flag is assigned to each of the 8 bits. FIG. 6 shows the bit assignment of flags. Of the 8 bits from the 0th bit to the 7th bit, the 7th bit from the upper side indicates that the corresponding edit unit includes a sequence header (Sequence_Header) and belongs to a closed GOP. The sixth bit indicates whether or not the corresponding edit unit includes a sequence header.

  The fifth bit indicates whether or not a frame included in the corresponding edit unit is decoded using forward prediction. The fourth bit indicates whether or not a frame included in the corresponding edit unit is decoded using backward prediction. The third bit indicates whether or not the offset of the frame included in the corresponding edit unit is out of range. The second bit is not used when MPEG mapping is performed (Not used by MPEG mapping).

  Two bits of the first bit and the 0th bit are used to indicate the picture type of the frame included in the corresponding edit unit. 2 bits of the first bit and the 0th bit are “00”, a frame by I picture is shown by “10”, a frame by P picture is shown by “10”, and a frame by B picture is shown by “11”.

  As can be seen from FIG. 5, when the frame #n which is the display order is designated, the coding order corresponding to the designated frame #n is referred to by referring to the temporal offset in the nth index entry in the index entry array. Can know. Furthermore, by referring to the key frame offset in the index entry corresponding to the coding order corresponding to the frame #n, it is possible to know the coding order of the first picture necessary for decoding the picture of the coding order. it can.

  That is, by using the temporal offset and the key frame offset, when the frame #n is designated in the display order, the first picture necessary for decoding the designated frame #n, that is, the editing unit file, is displayed. The position can be known for each index table segment. Therefore, when the system accesses a file, the index table in the file is first read in advance, thereby improving the accessibility to any frame in the file.

  However, the present invention is not limited to this, and the system can also read the index table sequentially from the top of the file according to the access order of the file. In this case, compared to an example in which all the index tables in the file are read in advance, accessibility to a portion where the index table is not read cannot be expected.

  Next, a recording format applicable to the first embodiment of the present invention will be described. FIG. 7 shows an example of data arrangement in the disc-shaped recording medium. The data arrangement shown in FIG. 7 as an example is a general data arrangement in a disc-shaped recording medium that can be randomly accessed, such as a recordable optical disk or hard disk. The logical address space is an area where arbitrary data can be recorded / reproduced.

  In the first embodiment, the recording medium is an optical disk. Note that the recording medium applicable to the first embodiment is not limited to an optical disk. That is, the first embodiment can be applied to other randomly accessible recording media such as a hard disk drive and a semiconductor memory. The above-described interleaved MXF file is formed as a virtual file based on data recorded on such a recording medium, for example. That is, the interleaved MXF file describes a predetermined correspondence with data recorded on the recording medium. For example, the user accesses the data actually recorded on the recording medium via the interleaved MXF file. .

  A file system FS is arranged at the leading and trailing ends of the logical address. Arbitrary data is recorded in a predetermined format generally called a file in the logical address space. Data on the recording medium is basically managed in file units. File management information is recorded in the file system FS. A file system layer of a system control unit (described later) of the recording / reproducing apparatus can manage various kinds of data on one recording medium by referring to and operating information of the file system FS. The file system FS uses, for example, UDF (Universal Disk Format), and manages files in units of 2 kB (kilobytes).

  A replacement area is arranged outside the logical address space. The spare area is an area that can be used as an alternative when a part of the recording medium cannot be physically read or written due to a defect. For example, when a defective area is recognized at the time of access to the recording medium (particularly at the time of recording), a replacement process is normally performed, and the address of the defective area is moved into the replacement area.

  The usage status of the spare area is stored as a defect list in a predetermined area, and is used by a drive control unit of the recording / reproducing apparatus and a lower hierarchy of the system control unit. In other words, in the lower layers of the drive control unit and system control unit described later, by referring to the defect list when accessing the recording medium, even when replacement processing is performed, access to an appropriate area is performed. It can be carried out. By this mechanism of the spare area, the host application can perform data recording / reproduction with respect to the recording medium without considering the presence / absence or position of the defective recording area on the recording medium.

  In the case of a disc-shaped recording medium, the replacement area is often arranged on the innermost or outermost side of the disc. When the disk rotation control is performed by zone control in which the rotation speed is changed stepwise in the radial direction of the disk, a replacement area may be provided for each zone. When the recording medium is not a disk-shaped recording medium such as a semiconductor memory, it is often arranged on the side having the smallest physical address or the largest physical address.

  In an application that handles audio data and video data (hereinafter collectively referred to as AV data), a group of data that is a unit that requires continuous synchronous reproduction, that is, reproduction that guarantees real-time reproduction is called a clip. For example, a group of data from the start to the end of shooting by the video camera is used as a clip. The entity of a clip consists of a single file or multiple files. In the present invention, a clip consists of a plurality of files. Details of the clip will be described later.

  For example, an NRT (Non Real Time) area in which an arbitrary file other than a clip can be recorded is arranged at the head side in the logical address space, and clips are sequentially packed from the next of the NRT area. The clip is arranged avoiding the defect position on the optical disc 1 so that the above-described replacement process is not performed. A header (H) and a footer (F) are added to each clip. In this example, the header and footer are arranged together on the rear end side of the clip.

  In the following description, it is assumed that the clip first recorded on the optical disc 1 is the clip # 1, and the clip numbers are subsequently increased as clip # 2, clip # 3,.

  In the logical address space, an area where no data is recorded or an area where data has been recorded in the past but is no longer needed is managed as an unused area in the file system FS. A recording area is allocated to a file newly recorded on the recording medium based on an unused area. The management information of the file is added to the file system FS.

  When a recordable optical disc is used as the recording medium, the present invention records the clip on the recording medium with an annual ring structure. The annual ring structure will be described with reference to FIGS. 8 and 9. FIG. 8A is an example showing one clip 50 on the timeline. In this example, the clip 50 includes seven files of video data 51, audio data 52A to 52D, auxiliary AV data 53, and real-time metadata 54.

  The video data 51 is video data obtained by compression-coding baseband video data at a high bit rate of, for example, a bit rate of 35 Mbps (megabit second). As a compression encoding method, for example, MPEG2 (Moving Pictures Experts Group 2) long GOP method is used. As the audio data 52A, 52B, 52C and 52D, baseband audio data is used, and each is audio data of one channel. However, the audio data 52A, 52B, 52C, and 52D may be audio data obtained by compression-coding baseband audio data at a high bit rate. The video data 51 and the audio data 52A to 52D are data to be actually broadcasted or edited, and are referred to as main line data.

  The auxiliary AV data 53 is data obtained by compressing and multiplexing baseband video data and audio data at a lower bit rate than main line video data and audio data. As the compression encoding method, for example, the MPEG4 method is used, and main line AV data is generated by compression encoding so as to reduce the bit rate to, for example, several Mbps. The auxiliary AV data 53 is data used as a proxy for main line data in order to perform high-speed search reproduction, and is also referred to as proxy data.

  Metadata is high-order data related to certain data, and functions as an index for representing the contents of various data. The metadata includes real-time metadata 54 generated along the time series of the main AV data and non-time series meta data generated for a predetermined section such as for each scene in the main AV data. There are two types of data. The non-time series metadata is recorded in, for example, the NRT area described with reference to FIG.

  As shown in an example in FIG. 8B, the clip 50 is divided on the basis of a predetermined reproduction time (for example, 2 seconds) and recorded on the optical disc as an annual ring structure. As an example is shown in FIG. 8C, one annual ring is a video data 51, audio data 52A to 52D, auxiliary AV data 53, and real-time metadata (RM) 54 so that the playback time zones correspond to each other. The data is divided into predetermined reproduction time units having a data size of one or more rounds, and the divided reproduction time units are sequentially arranged and recorded. That is, each data constituting the clip 50 is interleaved in a predetermined time unit by the annual ring structure and recorded on the optical disc.

  Data forming the annual ring is referred to as annual ring data. The annual ring data has an amount of data that is an integral multiple of the smallest recording unit on the disc. The annual rings are recorded so that the boundaries coincide with the block boundaries of the recording units of the disc.

  FIG. 9 shows an example of annual ring data formed on the optical disc 1. For example, as described with reference to FIG. 8B, annual ring data # 1, # 2, # 3,... In which one clip is divided into predetermined playback time units from the inner circumference side to the outer circumference side of the optical disc 1. .. is recorded continuously. That is, the data is arranged so that the reproduction time series is continuous from the inner circumference side to the outer circumference side of the optical disc 1. Although not shown, the NRT region is arranged further on the inner circumference side of the first annual ring data # 1 in the example of FIG.

  FIG. 10 shows an example of the data structure in the MPEG2 long GOP and an example of the correspondence relationship between the video MXF file. For example, as shown in FIG. 10A, one long GOP file is composed of one clip. As shown in FIG. 10B, the long GOP file corresponds to the structure of the video MXF file already described with reference to FIG. In the video MXF file, as described above, the header partition pack (HPP) and the header metadata are arranged from the top to form the header 13, and the essence container in which the video data body is stored in the subsequent file body. Be placed. At the end of the file, a footer partition pack (FPP) is arranged to form a file footer (not shown).

  The essence container has a configuration in which GOPs are arranged as shown in FIG. 10C. The contents of each GOP are a set of pictures as shown in FIG. 10D, and the contents of one picture are arranged with KL (Key, Length) information at the head, as shown in FIG. The main body of the I, P or B picture is arranged, and further KL information is arranged. A filler is arranged at the end of the picture as necessary, and the end is aligned in units of 2048 bytes.

  In such a configuration, in the MPEG2 long GOP, the information amount of each picture, that is, the values of the sizes of the I, P, and B pictures shown in FIG. 10E are uncertain. Therefore, for example, when playback is to be started from a certain frame in the long GOP video MXF file, the start position of the picture corresponding to that frame in the long GOP video MXF file cannot be specified by a byte position or the like.

  Therefore, with respect to each picture included in the long GOP video MXF file on the basis of the file address (see FIG. 10F) indicated in bytes from the head position of the long GOP video MXF file, the file address, size, and picture type (I, (P or B picture) and information indicating whether the picture is the first picture of the GOP are prepared as picture pointer information. This picture pointer information is prepared for each long GOP video MXF file.

  Note that the filler disposed at the end of the picture shown in FIG. 10E is adjusted so that the boundary of each picture is a multiple of a predetermined byte such as 2048 bytes as seen from the file address. As an example, it is preferable to adjust using a filler so that the boundary of each picture coincides with the boundary of the minimum access unit such as a sector of the optical disk 10 because access to each picture becomes easy.

  FIG. 11 shows a more specific example of a picture pointer table in which picture pointer information is described. In this example, the picture pointer table describes data in units of 8 bytes. The first 8 bytes store the reserved area and version information of this picture pointer table. Hereinafter, 8 bytes are allocated to one frame, that is, one picture, and this 8-byte information is arranged by the number of pictures included in the long GOP video file. Each picture is arranged in the order of display frames.

  Data for each picture will be described. The first 1 bit is a flag indicating whether or not the picture is the first picture of the GOP. For example, assuming that there are a plurality of I pictures in one GOP, the boundary of the GOP cannot be specified only by the position of the I picture. If the GOP boundary cannot be specified, the position of the sequence header (Sequence Header) defined in MPEG2 cannot be known, and there is a possibility that there is no sequence header at the head of the stream input to the decoder. Such a state can be avoided by providing each picture with a flag indicating whether or not this is a GOP head picture. At the time of reproduction, a stream is input to the decoder based on this flag.

  The next 23 bits store picture size information as shown in FIG. 10E. By securing 23 bits as size information, it is possible to cope with a data size up to 8 MB (megabytes), and it is also possible to cope with MPEG profile 422 @ HL.

The next two bits indicate the picture type. For B pictures, reference direction information is also shown. More specifically, the picture type is described as follows, for example.
00: I picture 10: P picture 01: B picture restored by referring backward from only future frames. This is, for example, a B picture at the beginning of a long GOP video file in the case of an open GOP, or a B picture at the beginning of each GOP in the case of a closed GOP.
11: B picture restored by referring to the front and rear frames.

  The next 38 bits indicate a file address in the long GOP video file of the picture. By assigning 38 bits to the file address, a long GOP video file having a size up to 256 GB (gigabytes) can be supported. For example, it is possible to deal with the optical disc 1 in which up to eight recording layers each having a recording capacity of 27 GB are formed.

  This picture pointer table is recorded as a picture pointer file in the NRT area of the recording medium, for example, together with non-time series metadata. When the optical disc 1 is loaded into the system, the non-time series metadata and the picture pointer file recorded in the NRT area are read by the system, and the optical disc 1 is mounted on the system. The read non-time series metadata and picture pointer file are held in a memory included in the control unit of the system, for example. The control unit of the system can access any picture in the clip recorded on the optical disc 1 by referring to the picture pointer table held in the memory.

  Next, a recording / reproducing apparatus applicable to the first embodiment of the present invention will be described. FIG. 12 shows an example of the configuration of a recording / reproducing apparatus 100 applicable to the first embodiment of the present invention. The recording / reproducing apparatus 100 can use the optical disc 1 described above as a recording medium.

  The recording-side video signal processing unit 101 performs predetermined signal processing on the input baseband digital video data. The MPEG encoder 102 performs compression encoding processing in accordance with MPEG2 default for the digital video data supplied from the recording-side video signal processing unit 101, and outputs MPEG ES (MPEG elementary stream). That is, the MPEG encoder 102 performs intra-frame compression on the supplied digital video data using DCT (Discrete Cosine Transform), and performs inter-frame compression using predictive coding. Further, variable length coding is performed on the data subjected to the intra-frame compression and the inter-frame compression.

  The memory controller 103 is connected to RAMs (Random Access Memory) 104A and 104B, controls the buffering of video data and audio data related to recording and reproduction to the RAM 104A and / or 104B, and performs the above-described video processing on the recording side. Data between each unit to be performed, a disk drive unit 105 (to be described later) and a CPU (Central Processing Unit) 121 for controlling the whole, a unit for performing video processing on the reproduction side, a unit for performing audio processing, and the like Controls command exchange.

  The RAM 104A is composed of, for example, SDRAM (Synchronous Dynamic RAM), and can store video data and audio data for one to a plurality of annual rings and other data temporarily by using, for example, an annual ring image which is a recording format of the optical disc 1. Is done. The RAM 104B is made of, for example, an SRAM (Static RAM) and buffers audio data. The memory controller 103 can perform access control to the RAMs 104A and 104B by DMA (Direct Memory Access) control without using the CPU 121 described later.

  As will be described in detail later, the disk drive unit 105 records data on the loaded optical disk 1 and reproduces data recorded on the optical disk 1. The disk drive unit 105 is connected to the memory controller 103 through a predetermined interface such as ATA (AT Attachment), and can access a predetermined address of the optical disk 1 based on commands and address information supplied via the interface. ing.

  The MPEG decoder 106 decodes the video data that is supplied from the memory controller 103 and that has been compression-encoded with a compression-encoding system that conforms to the MPEG2 default. The MPEG decoder 106 has a frame buffer (not shown) that can store a plurality of decoded frames, and stores the decoded frames in the frame buffer. For example, the MPEG decoder 106 decodes forward and / or backward reference pictures using the frames stored in the frame buffer, and controls the output timing of the frames based on a predetermined output control command.

  The playback-side video processing unit 108 performs predetermined signal processing on the baseband digital video data decoded by the MPEG decoder 106 and outputs the processed signal to the outside. The playback-side video processing unit 108 is connected to an auxiliary AV (V) unit 107 that performs processing on the video data side in the auxiliary AV data.

  The auxiliary AV (V) unit 107 performs processing on the video data portion of the auxiliary AV data. For example, the auxiliary AV (V) unit 107 performs a predetermined compression encoding process on the video data supplied from the recording-side video processing unit 101 to create a video data portion of the auxiliary AV data. The video data portion of the created auxiliary AV data is supplied to the memory controller 103 via the playback-side video processing unit 108. The auxiliary AV (V) unit 107 also performs a process of decoding the video data portion of the auxiliary AV data supplied from the memory controller 103 via the playback-side video processing unit 108. The digital video data obtained by decoding the video data portion of the auxiliary AV data is supplied to the reproduction side video processing unit 108.

The audio processing unit 109 performs input / output processing relating to digital and analog audio signals. For example, the input digital audio data is subjected to predetermined signal processing and supplied to the memory controller 103 and an auxiliary AV (A) unit 110 described later. Also, the digital audio data supplied from the memory controller 103 or the auxiliary AV (A) unit 110 is subjected to predetermined signal processing and output to the outside. Further, the audio processing unit 109 D / A converts an analog audio signal supplied from the outside into digital audio data, and supplies the digital audio data to the memory controller 103 and the auxiliary AV (A) unit 110. Furthermore, the audio processing unit 103 performs A / D conversion on the digital audio data supplied from the memory controller 103 and the auxiliary AV (A) unit 110 and outputs the digital audio data to the outside as an analog audio signal.

  The auxiliary AV (A) unit 110 processes the audio data portion of the auxiliary AV data. For example, the auxiliary AV (A) unit 110 performs a predetermined compression encoding process on the digital video data supplied from the audio processing unit 109 to create an audio data portion of the auxiliary AV data. The audio data portion of the created auxiliary AV data is supplied to the memory controller 103. Further, the auxiliary AV (A) unit 110 decodes the audio data portion of the auxiliary AV data supplied from the memory controller 103 and supplies the decoded audio data to the audio processing unit 109.

  A bus 120 is connected to the memory controller 103. A CPU 121 is connected to the bus 120. A RAM 122, a ROM (Read Only Memory) 123, and a connector 124 are further connected to the CPU 121 via a bus. The CPU 121 controls the entire recording / reproducing apparatus 100 using the RAM 122 as a work memory in accordance with a program stored in the ROM 123 in advance. The connector 124 is for attaching a non-volatile memory 125 that is removable. Note that a path for exchanging commands and data between the CPU 121 and each unit of the recording / reproducing apparatus 100 is omitted in FIG. 12 in order to avoid complexity.

  A communication interface (I / F) 126 is further connected to the bus 120. The communication I / F 126 performs communication between the recording / reproducing apparatus 100 and an external device by a communication method according to, for example, IEEE (Institute Electrical and Electronics Engineers) 1394 standard. The communication method applied to the communication I / F 126 is not limited to IEEE 1394, and may be USB (Universal Serial Bus), for example.

  Furthermore, the bus 120 is connected to the bus 131 via the bridge 130. To the bus 131, a CPU 132, a memory 133, and a communication interface (I / F) 134 are further connected. The communication I / F 134 is connected to a LAN (Local Area Network), for example, and performs communication using TCP / IP (Transmission Control Protocol / Internet Protocol) as a communication protocol. The CPU 132 controls communication by the communication interface (I / F) 134 using the RAM 133 as a work memory in accordance with a program stored in advance in a ROM (not shown). For example, the CPU 132 can perform file transfer by the communication I / F 134 using FTP (File Transfer Protocol).

  For example, if the above-described ROM 123 is a rewritable ROM such as an EEPROM (Electrically Erasable Programmable Read Only Memory), the program stored in the ROM 123 can be updated later. Program data for updating is supplied to the recording / reproducing apparatus 100 via, for example, a LAN, received by the communication I / F 134, supplied to the CPU 121 via the bus 131, the bridge 130, and the bus 120, and based on the control of the CPU 121. It is written in the ROM 123. Program data for updating may be supplied from the outside via the communication I / F 126, stored in the removable memory 125, and supplied from the memory 125 via the interface 124.

  A reference synchronization signal for synchronizing video data and audio data is supplied to the timing generator (TG) 140 from the outside. The timing generator 140 generates various timing signals used in the recording / reproducing apparatus 100 based on the supplied reference synchronization signal. The generated timing signal is supplied to a corresponding part in the recording / reproducing apparatus 100 (not shown) according to the type of signal.

  The operation on the recording / reproducing apparatus 100 can be performed based on a command supplied from the outside via the communication I / F 126 or the communication I / F 134, for example. That is, the CPU 121 exchanges data and commands with an external device via the communication I / F 126 and the communication I / F 134, receives an operation command from the external device, and receives status information of the recording / playback apparatus 100 from the external device. Send to. Based on the exchange with the external device, the CPU 121 controls each part of the recording / reproducing apparatus 100 in a predetermined manner.

  Of course, the present invention is not limited to this, and an operation unit may be provided for the recording / reproducing apparatus 100, and the recording / reproducing operation may be controlled according to the operation on the operation unit.

  FIG. 13 shows an exemplary configuration of the disk drive unit 105 of the recording / reproducing apparatus 100. At the time of recording, the recording data supplied from the memory controller 103 is stored in the memory 157 via an ECC (Error Correction Coding) unit 158 and the memory controller 156. The memory controller 156 controls access to the memory 157 based on the control of the control unit 150. The control unit 150 includes a microcomputer, and controls the disk drive unit 105 based on a control signal from the memory controller 156.

  An error correction code is generated for each error correction unit by the ECC unit 158 for the recording data stored in the memory 157. A product code can be used as an error correction code for video data and audio data. In the product code, the outer code is encoded in the vertical direction of the two-dimensional array of video data or audio data, the inner code is encoded in the horizontal direction, and the data symbols are encoded doubly. As the outer code and the inner code, a Reed-Solomon code can be used. A data unit completed with a product code is called an ECC block. The ECC block has a size of 64 kbytes (65536 bytes), for example. The memory controller 156 reads the ECC block from the memory 157 and supplies it as recording data to the modulation / demodulation unit 155. The modulation / demodulation unit 155 generates a recording signal by modulating the recording data, and supplies the recording signal to the pickup unit 152.

  The pickup unit 152 controls the output of the laser beam based on the recording signal supplied from the modulation / demodulation unit 155 and records the recording signal on the optical disc 1 that is rotationally driven by the spindle motor 151.

  The pickup unit 152 photoelectrically converts the reflected light from the optical disc 1 to generate a current signal, and supplies it to an RF (Radio Frequency) amplifier 153. The RF amplifier 153 generates a focus error signal, a tracking error signal, and a reproduction signal based on the current signal from the pickup unit 152, and supplies the tracking error signal and the focus error signal to the servo control unit 154. The RF amplifier 153 supplies a reproduction signal to the modulation / demodulation unit 155 at the time of reproduction.

  The irradiation position of the laser light is controlled to a predetermined position by a servo signal supplied from the servo control unit 154 to the pickup unit 152. That is, the servo control unit 154 controls the focus servo operation and the tracking servo operation. Specifically, the servo control unit 154 generates a focus servo signal and a tracking servo signal based on the focus error signal and the tracking error signal from the RF amplifier 153, and supplies them to an actuator (not shown) of the pickup unit 152. . The servo control unit 154 generates a spindle motor drive signal for driving the spindle motor 151 and controls the spindle servo operation for rotating the optical disc 5 at a predetermined rotational speed.

  Further, the servo control unit 154 performs thread control for moving the pickup unit 152 in the radial direction of the optical disc 1 to change the irradiation position of the laser beam. The signal reading position of the optical disc 5 is set by the control unit 150 based on the control signal supplied from the memory controller 103, and the pickup unit 152 can read the signal from the set reading position. The position is controlled.

  The spindle motor 151 rotates and drives the optical disc 1 with a constant linear velocity CLV (Constant Linear Velocity) or a constant angular velocity CAV (Constant Angler Velocity) based on a spindle motor drive signal from the servo controller 154. The driving method of the spindle motor 112 can be switched between CLV and CAV based on a control signal from the signal processing unit 3.

  During reproduction, the pickup unit 152 condenses and irradiates the optical disc 1 with laser light, and supplies the RF amplifier 153 with a current signal obtained by photoelectrically converting reflected light from the optical disc 1. The modulation / demodulation unit 155 demodulates the reproduction signal supplied from the RF amplifier 153 to generate reproduction data, and supplies the reproduction data to the memory controller 156. The memory controller 156 writes the supplied reproduction data into the memory 157. Reproduction data is read from the memory 157 in units of ECC blocks and supplied to the ECC unit 158.

  The ECC unit 158 performs error correction by decoding the error correction code of the supplied reproduction data in units of ECC blocks. When an error is detected exceeding the error correction capability of the error correction code, an error flag is set for the error correction unit without performing error correction. The reproduction data output from the ECC unit 158 is supplied to the memory controller 103.

  In the above configuration, digital video data and digital audio data are input to the recording / reproducing apparatus 100 during recording. The digital video data is subjected to predetermined signal processing by the recording-side video processing unit 101, compressed and encoded by the MPEG encoder 102 according to a method according to the MPEG2 standard, and supplied to the memory controller 103. The digital audio data is subjected to predetermined signal processing by the audio processing unit 109 and supplied to the memory controller 103.

  On the other hand, digital video data is supplied from the recording-side video processing unit 101 to the auxiliary AV (V) unit 107. The auxiliary AV (V) unit 107 compresses and encodes the supplied digital video data so that the bit rate is about several Mbps, for example, by a compression encoding method stipulated in MPEG4, and the video data portion of the auxiliary AV data Get. The video data portion of the auxiliary AV data is supplied to the memory controller 103. Also, the digital audio data output from the audio processing unit 109 is supplied to the auxiliary AV (A) unit 110. For example, using thinning and A-law encoding, the sampling frequency and the number of quantization bits are reduced, and compression encoding is performed. This is supplied to the memory controller 103.

  The memory controller 103 is supplied with the supplied digital video data compressed and encoded by the MPEG encoder 102, the digital audio data supplied from the audio processing unit 109, the auxiliary AV (V) unit 107, and the auxiliary based on the instruction of the CPU 121. The auxiliary AV data including the data supplied from the AV (A) unit 106 is stored in, for example, the RAM 104A in a predetermined manner. At this time, the memory controller 103 maps the supplied compressed digital video data, digital audio data, and auxiliary AV data on the RAM 104A so as to correspond to the above-described annual ring format.

  The memory controller 103 reads data from the RAM 104A and supplies the read data to the disk drive unit 105 together with a write command when predetermined data is accumulated on the RAM 104A based on a command from the CPU 121. The disk drive unit 105 records the supplied recording data on the optical disk 1 in an annual ring format based on a write command.

  At the time of reproduction, when the optical disc 1 is loaded in the disc drive unit 105, the disc drive unit 105 reads the file system FS on the optical disc 1. The CPU 121 supplies a command for reading a file on the optical disc 1 to the disc drive unit 105 via the memory controller 103. In accordance with this command, the disk drive unit 105 accesses a file specified based on the read file system FS. The disk drive unit 105 reads data from the optical disk 1 in units of annual rings and supplies it to the memory controller 103. The memory controller 103 stores the supplied data as, for example, an annual ring image in the RAM 104A. Audio data is stored in the RAM 104B.

  The memory controller 103 reads data from the RAM 104A when data of a predetermined amount or more is accumulated in the RAM 104A. For example, the digital video data read from the RAM 104A is supplied from the memory controller 103 to the MPEG decoder 106, and the compressed code is decoded to obtain baseband digital video data. This digital video data is supplied to the reproduction-side video processing unit 108, subjected to predetermined signal processing, and output.

  The digital audio data read from the RAM 104A is also supplied from the memory controller 103 to the audio processing unit 109, and is subjected to predetermined signal processing and output.

  The auxiliary AV data read from the RAM 104A is supplied to the auxiliary AV (V) unit 107 from the memory controller 103 via the playback-side video processing unit 108. The video data portion of the auxiliary AV data is decoded by the auxiliary AV (V) 107 and output through the playback-side video processing unit 108. The audio data part of the auxiliary AV data read from the RAM 104A is supplied from the memory controller 103 to the auxiliary AV (A) part 110. The audio data part of the auxiliary AV data is compressed by the auxiliary AV (A) part. The code is decoded and output via the audio processing unit 109.

  Next, a first embodiment of the present invention will be described. In the present invention, when digital video data recorded on a recording medium such as the optical disc 1 is read out, an index table including information indicating a recording position for each frame is generated for a predetermined range including the read data position. And store it in the memory. For an external device such as a computer device that accesses the recording medium and reproduces data, the index table stored in the memory is presented as information indicating the recording contents of the recording medium. That is, on the external device side, the recording medium to be accessed is virtually shown as an interleaved MXF file based on the information in this index table.

  For example, the index table is held in the memory until the clip is closed, and is used again when the position described in the index table is accessed next time. When the location described in the index table is accessed many times, the processing becomes efficient.

  For example, in the above example, when data is read from the optical disc 1 and written to the RAM 104A, the CPU 121 creates an image of an interleaved MXF file based on the data written to the RAM 104A, and creates an index table and each partition table. Such table information is held on the RAM 122. For example, the CPU 121 refers to the information in the picture pointer table read from the optical disc 1 and written in the RAM 104A, and creates table information such as the index table and each partition table.

  Not limited to this, only the data in the NRT area is read from the optical disk to extract the picture pointer table, and the table information such as the index table and each partition table is created from the picture pointer table without reproducing the video data or the like. You may do it.

  The CPU 121 accesses the data stored in the RAM 104 </ b> A based on the information held on the RAM 122. In this way, for example, data recorded in the annual ring format on the optical disc 1 is displayed as data in the interleaved MXF format to an external device connected by the communication I / F 134 or the communication I / F 126. be able to. That is, the external device can handle the optical disc 1 mounted on the recording / reproducing apparatus 100 or the recording / reproducing apparatus 100 itself as a storage apparatus connected to the external device. Thus, the external device can handle the clip recorded on the optical disc 1 as a file. Such an operation mode in the recording / reproducing apparatus 100 is called a file access mode.

  Hereinafter, the first embodiment of the present invention will be described in more detail. FIG. 14 conceptually shows the construction of an interleaved MXF file according to the first embodiment of the present invention. As described above, each piece of data (video data and one or more channels of audio data) constituting a clip is recorded on the optical disc 1, and a picture pointer table is recorded in the NRT area. When the optical disc 1 is loaded into the recording / reproducing apparatus 100, for example, a picture pointer table, a file system, etc. are read into the system, and the optical disc 1 is mounted on the system.

  When an access to video data of a clip recorded on the optical disc 1 is instructed, an index table is created for a predetermined range for the address instructed to access based on a picture pointer table read into the system. Is stored in the cache memory. At the same time, each data constituting the clip in the range corresponding to the created index table is interleaved for each frame to create an edit unit. The created edit unit is stored in the cache memory for the edit unit.

  The index table stored in the index table cache memory and the edit unit stored in the edit unit cache memory are held until the clip is closed. When access is instructed to the edit unit described in the index table stored in the cache memory, the index table or edit unit stored in the cache is taken out and presented or output. By such processing, processing related to the index table is made efficient.

  This will be described in more detail with reference to FIG. It is assumed that the above-described annual ring format is applied to the optical disc 1. As shown in FIG. 15A, when an output frame is instructed with respect to a certain clip recorded on the optical disc 1, each data (video data and video data) constituting the clip for a predetermined range before and after the instructed output frame. Audio data) is read from the optical disc 1 in annual rings, and the picture pointer information is referred to, and the partition table 200 and the body table 201 in the corresponding ranges are created. The partition table 200 and the body table 201 will be described later.

  Video data and audio data read from the optical disc 1 are interleaved in units of frames to create an edit unit. The created edit unit is stored in the cache memory 202 for the edit unit (see FIG. 15B).

  On the other hand, an index table 203 is created from the partition table 200 and the body table 201 created based on the picture pointer information. The created index table 203 is stored in the index table cache memory 204 (see FIG. 15B). The index table 203 is created sequentially only for the accessed part. For example, if the information of the frame to which access is instructed next is not described in the already created index table 203, a new index table is created corresponding to the frame. The cache memory 204 for the index table has a capacity that can store all the index tables of the clip in advance.

  An output interleaved MXF file 205 is formed by the edit units and index tables stored in the cache memories 202 and 204. As will be described in detail later, the output interleaved MXF file 205 can express the contents of a clip using a directory structure based on an index table.

  For example, an index file in which information of each piece of data constituting a clip is described is placed under the root directory, and a clip directory in which clip data is stored is formed. Under the clip directory, one file is placed for each piece of data constituting the clip. This means that, for example, when the interleaved MXF file 205 is transferred to the computer apparatus, the clip stored in the interleaved MXF file 205 can be handled as one file on the computer apparatus. That is, by configuring the interleaved MXF file 205 in this way, a clip recorded in the annual ring format or the like on the optical disc 1 can be easily processed by a computer device.

  The partition table 200 and the body table 201 described above will be described more specifically. First, the body table 201 will be described with reference to FIG. FIG. 16A shows the configuration of the essence container described in FIG. 2B. In the body table 201, information on each edit unit included in the essence container is described in the order of coding order.

  In the information of each edit unit, a temporal offset and a key frame offset are described with a data length of 3 bits and 5 bits in the first 1 byte, respectively, and then a flag (see FIG. 6) is described with a data length of 1 byte. The Furthermore, a picture item size indicating the size of the picture stored in the edit unit is described, and then an offset of the edit unit with respect to the essence container is described. In the example of FIG. 16, the picture item size is described with a data length of 2 bytes divided by 256, and the offset to the essence container of the edit unit is described with a data length of 4 bytes divided by 256. The

  Each data described in the body table 201 can be obtained from the data described in the picture pointer table. For example, the temporal offset, the key frame offset, and the flag can be obtained based on the arrangement order (display order) of the picture pointer table, the flag indicating whether or not the head of the GOP is present, the picture type, and the like. Further, the picture item size and the edit unit offset can be obtained based on the picture size and the picture offset of the picture pointer table, respectively.

  Next, the partition table 200 will be described with reference to FIG. FIG. 17A shows the overall configuration of the interleaved MXF file described in FIG. 2A and the like. In the partition table 200, as shown in FIG. 17B, the offset information of the body partition pack is described with a data length of 8 bytes, and the offset of the edit unit in the body partition pack is described with a data length of 4 bytes. The

  In the example of FIG. 17B, the offset from the beginning of the interleaved MXF file is described in the 0th line, which is the first line of the partition table 200, for body partition # 0 starting from the first body partition pack of the interleaved MXF file. The offset of the first edit unit # 0 of the body partition # 0 is described. Note that the offset from the beginning of the interleaved MXF file is the same as the header size. Thereafter, the offset information of each body partition and the offset of the first edit unit of the body partition are described from the first line. The last Nth line describes the offset of the footer partition pack arranged at the head of the footer part of the interleaved MXF file.

  Each data described in the partition table 200 is generated based on the structure of the interleaved MXF file. That is, when the number of edit units stored in the body partitions delimited by each body partition pack is determined, the data described in the partition table 200 is based on the data described in the body table 201 or the picture pointer table described above. It is decided. The number of edit units stored in each body partition is preset by the system, for example.

  Here, the data sizes of the partition table 200 and the body table 201 described above are calculated. As an example, it is assumed that one body partition stores data constituting a clip for approximately 10 seconds in reproduction time. If the frame frequency is 30 Hz (29.97 Hz), 300 frames of video data and audio data are stored in one body partition. In addition, it is assumed that clips of up to 3 hours can be recorded on the optical disc 1. That is, a maximum of 1080 partitions are formed on the optical disc 1, and 324,000 frames can be recorded.

  Under such conditions, the body table 201 has a data length of 8 bytes per edit unit, that is, one frame, so that the data capacity is 324,000 frames × 8 bytes = 2,592,000 bytes. Since the partition table 200 has a data length of 12 bytes per partition, the data capacity is 1080 partitions × 12 = 12,960 bytes. Therefore, when creating the index table 203 for the optical disc 1, it is necessary to secure 2,592,000 bytes + 12,960 bytes = 2,604,960 bytes as a work area.

Next, a procedure for creating an interleaved MXF file will be described with reference to FIGS. FIG. 18 shows a part extracted from the recording / reproducing apparatus 100 described with reference to FIG. 12, which is deeply related to the creation of the interleaved MXF file. In FIG. 18, parts corresponding to those in FIG. 12 described above are denoted by the same reference numerals, and detailed description thereof is omitted. In creating the interleaved MXF file, the memory controller 103 reads data from the optical disc 1 and accesses the RAMs 104A and 104B to predetermined control, and the main CPU 121 uses the index table based on the data written in the RAMs 104A and 104B. And an edit unit is created. The created index table is stored on the RAM 122 connected to the main CPU 121. The edit unit is stored in the RAM 104A .

  When an access request for a clip recorded on the optical disc 1 is supplied from an external device such as a computer device connected via the communication I / F 126, the main CPU 121 transmits the index table stored in the RAM 122 to the communication I. Presented to external device via / F126. The external device instructs an edit unit to be accessed based on the presented index table. In response to this instruction, the main CPU 121 reads the edit unit from the RAM 104A based on the index table and transfers it to the external device via the communication I / F 126.

  Hereinafter, the process of creating an interleaved MXF file will be described step by step based on the configuration of FIG. FIG. 19 is a flowchart showing an exemplary procedure for creating an interleaved MXF file. 20 to 24 schematically show the flow of data accompanying the flowchart of FIG. FIG. 25 schematically shows a state of an interleaved MXF file formed in accordance with the flowchart of FIG. For example, as shown in FIG. 25, the interleaved MXF file is transferred via the communication I / F 126.

  First, prior to the processing of the flowchart of FIG. 19, the optical disc 1 is loaded into the recording / reproducing apparatus 100, the file system FS is read from the optical disc 1, and the non-time series meta including the picture pointer recorded in the NRT area is included. Data, RT metadata of the clip recorded from the next of the NRT area, header and footer information, etc. are read out. By reading these data from the optical disk 1, the optical disk 1 is mounted on the system of the recording / reproducing apparatus 100, and the system of the recording / reproducing apparatus 100 becomes accessible to the clip data recorded on the optical disk 1.

  Thus, after the optical disc 1 is mounted on the system of the recording / reproducing apparatus 100, for example, an external device connected via the communication I / F 126 has an access request for a clip recorded on the optical disc 1. First, the requested access position is searched based on the picture pointer table. In step S10, the main CPU 121 creates a partition table 200 and a body table 201 for a predetermined range before and after the position where an access request is made based on the picture pointer table, and stores it in a predetermined area of the RAM 122 (FIG. 20). SEQ10). In step S11, the main CPU 121 creates an index table and a body partition pack template in a predetermined area of the RAM 122 (SEQ11 in FIG. 20).

  In the next step S12, the CPU 121 creates index table data and body partition pack data based on the partition table 200 and the body table 201 stored on the RAM 122. The created data is inserted into the template created in step S11 (SEQ12 in FIG. 21), is converted into a predetermined format, transferred to a predetermined area of the RAM 104A, and stored (SEQ13 in FIG. 21). Here, the predetermined area of the RAM 104A is used as the cache memory 204 for the index table.

  At this stage, as shown in FIG. 25A, only the header partition pack and header metadata portion stored on the RAM 104A are transferred to the interleaved MXF file.

  In the next step S13, the index table and the body partition pack stored in the cache memory 204 are transferred to the RAM 122 for each partition (SEQ14 in FIG. 22). These transferred data are stored in a predetermined bank on the RAM 122. The bank provided on the RAM 122 is a bank for virtually presenting a clip recorded on the optical disc 1 to an external device connected via the communication I / F 126 using an index table. . In the file access mode, the clip recorded on the optical disc 1 is presented to the outside through the bank on the RAM 122.

  In the next step S14, the index table stored in the bank is sent to the external device via the communication I / F 126 (SEQ15 in FIG. 22). In other words, the interleaved MXF file transferred via the communication I / F 126 at this stage becomes a part of the header metadata and the index table, as shown in FIG. 25B.

  In the next step S15, the RT metadata stored in the RAM 104A is read into the main CPU 121 (SEQ16 in FIG. 23), and the main CPU 121 generates a system item for one frame. The generated system item is stored in a predetermined area of the RAM 104A (SEQ17 in FIG. 23).

  In the next step S16, video data and audio data corresponding to the created index table are read from the optical disc 1. The read video data and audio data are written in a predetermined area of the RAM 104A as an annual ring image (SEQ18 in FIG. 23). Here, the audio data written in the RAM 104A is interleaved with audio data of one to a plurality of channels. In step S17, the audio data interleaved with the channel written on the RAM 104A is written to the RAM 104B in units of one frame (SEQ19 in FIG. 23).

  At this stage, the interleaved MXF file transferred via the communication I / F 126 is part of the header metadata and the index table, as shown in FIG. 25C as an example.

In the next step S18, the main CPU 121 reads out video data and system items from the RAM 104A and audio data from the RAM 104B based on information in the picture pointer table (SEQ20 in FIG. 24). In step S18, the read video data, system item, and audio data are transmitted to the outside by the communication I / F 126 via the bank used in the file access mode of the RAM 122 (SEQ21 in FIG. 24). That is, the video data and the audio data constitute an edit unit in units of one frame on the bank of the RAM 122 together with the system item as a picture item and an audio item in the interleaved MXF file, respectively, and are transmitted via the communication I / F 126. .

  That is, in the interleaved MXF file at this stage, as shown in FIG. 25D, edit units are sequentially transmitted in units of frames following the header metadata and the index table.

  The above processing from step S10 to step S18 is appropriately executed according to a read command for data recorded on the optical disc 1, and an index table is sequentially created. For example, it is conceivable to control the processing as in the flowchart shown in FIG. It is assumed that a computer device as an external device is connected to the recording medium device 100 via the communication I / F 126.

  In the flowchart of FIG. 26, when the optical disc 1 is loaded into the recording / reproducing apparatus 100 in step S30, the file system of the optical disc 1, the non-time-series metadata in the NRT area, the picture pointer table, etc. are read and the optical disc 1 is recorded. The clip is mounted on the system of the playback apparatus 100 and can access a clip recorded on the optical disc, for example.

  For example, when a user performs an operation of playing a clip recorded on the optical disc 1 from a certain position on a computer device connected as an external device to the communication I / F 126, the computer device changes the recording / playback device 100. On the other hand, an instruction to open the clip is sent out and supplied to the main CPU 121 (step S31). The clip playback position is specified using, for example, a frame or a time code. The clip playback position can also be specified by scrub playback, in which the playback position is freely moved back and forth using, for example, a jog dial operation.

  Based on this instruction, the main CPU 121 determines whether or not an index table in which information of an edit unit corresponding to the designated frame is described exists on the cache memory 204 (step S32). If it is determined that the index table exists on the cache memory 204, the process proceeds to step S34.

  On the other hand, if it is determined that the index table does not exist on the cache memory 204, the process proceeds to step S33. In step S33, predetermined data is read from the optical disc 1 according to the process illustrated in the flowchart of FIG. 19 described above, and an index table and an essence container are created by the main CPU 121. The index table and essence container are cached in the RAM 122.

  In the next step S34, the edit unit corresponding to the position designated for reproduction is read from the RAM 122 based on the index table. The read edit unit is transferred to the computer device which is an external device via the communication I / F 126. At this time, the corresponding index table is also transferred.

  In step S35, it is determined whether or not the clip currently being accessed is closed. If it is determined that the clip has been closed, the process proceeds to step S35, the cache is cleared, and the index table and essence container stored in the RAM 122 are discarded.

  On the other hand, if it is determined in step S35 that the clip is not closed, the process returns to step S31, and the clip is received in accordance with a playback instruction supplied from the computer device, which is an external device, via the communication I / F 126. Playback from the next playback position is performed. In step S 32, it is determined whether or not the edit unit corresponding to the position instructed to be reproduced is cached in the RAM 122. If it is determined that the data is cached, the cached data is read from the RAM 122. If it is determined that the data is not cached, a new index table and essence container are created and added to the RAM 122. Cached.

  If a more specific example is used, when the optical disc 1 is mounted on the system and the reproduction position is designated first, there is no data cached in the RAM 122, so an index table and an essence container are created in step S33. , Cached in the RAM 122. For example, as schematically shown in FIG. 27, when a frame designated for reproduction corresponds to the edit unit 300, a body partition 301 including the edit unit 300 is created and the body partition 301 is managed. An index table 302 is created. The index table for managing the previous body partition included in the body partition 301 does not need to store actual data.

  If the clip is not closed in step S35, the process returns to step S31, and the frame designated for playback is a frame corresponding to the edit unit 303 included in the body partition 301 already cached in the RAM 122. The edit unit 303 cached in the RAM 122 is read and transferred (step S34).

  On the other hand, if the frame designated for reproduction in step S31 after step S35 is a frame corresponding to the edit unit 304 of FIG. 27, the body partition 305 including the edit unit 304 is not cached in the RAM 122. Therefore, in step S33, an edit unit included in the body partition 305 and an index table for managing the body partition 305 are newly created (step S33) and added to the RAM 122 and cached.

  FIG. 28 collectively shows generation of each data when the above-described interleaved MXF file is created. A picture pointer is generated by a file manager (FM) corresponding to the recording format in the optical disc 1. The picture pointers are arranged in display order and consist only of picture items. By the metadata (Meta), a header, a body partition pack, and an index table template are generated when the file is opened. The metadata is non-time series metadata recorded in the NRT area of the optical disc 1, for example. In addition, when the file is opened, the body table and the partition table are generated based on the picture pointer by the MXF file manager (MXFM) corresponding to the interleaved MXF file. The body table is arranged in coding order and includes all items such as pictures and audio.

  The MXF file manager generates a body partition pack from the body partition pack template based on the body partition offset of the partition table. The body partition pack is updated in units of partitions by the MXF file manager. Further, the MXF file manager generates an index table from the index table template based on the body partition offset of the partition table and the temporal offset, key frame offset, flag, stream offset, and slice offset of the body table. The index table is updated in units of partitions and frames. The stream offset is based on the edit unit offset of the body table. The slice offset is based on the picture item size in the body table.

  Furthermore, a random index pack (RIP) is generated by the MXF file manager based on all pieces of partition information in the partition table.

  A method for presenting an interleaved MXF file created as described above to an external device connected via the communication I / F 126 will be described with reference to FIG. FIG. 29 shows an example of the management structure of data recorded on the optical disc 1. As already described, the data on the optical disc 1 is managed in a directory structure by the file system. In the example of FIG. 29, a directory PROAV is provided immediately below a root directory (not shown), and clip data and the like recorded on the optical disc 1 are defined below the directory PROAV.

  As an example, a file “INDEX.XML” and a file “DISCINFO.XML” are placed immediately below the directory PROAV, and a directory CLPR is provided.

  The directory CLPR manages clip data. For example, the clip here is a set of clip data from when shooting is started to when it is stopped. The clip data is generated from the above-mentioned main line audio data and video data, and the audio data and video data. Auxiliary AV data, time series metadata corresponding to the audio data and video data, and non-time series metadata. In the directories “C0001”, “C0002”,... Provided immediately below the directory CLPR, a group of data constituting the clip is stored for each clip.

  That is, it can be considered that each directory “C0001”, “C0002”,... For each clip corresponds to one interleaved MXF file.

  With respect to the directory “C0001” corresponding to one clip “C0001” provided immediately below the directory CLPR, each data constituting the clip is stored by being distinguished by a file name. In the example of FIG. 29, the file name is composed of 12 digits, and among the 8 digits before the delimiter “.”, The front 5 digits are used to identify the clip, and the 3 digits immediately before the delimiter are the audio digits. Used to indicate the type of data, such as data, video data, auxiliary AV data. Further, the three digits after the delimiter are an extension and indicate the data format.

  More specifically, in the example of FIG. 29, as a group of files constituting the clip “C0001”, a clip information file “C0001C01.SMI” indicating clip information, a main video data file “C0001V01.MXF”, For example, audio data files “C0001A01.MXF” to “C0001A08.MXF” for 8 channels of the main line system, auxiliary AV data file “C0001S01.MXF”, non-time series metadata file “C0001M01.XML”, time series metadata file “ “C0001R01.BIM” and pointer information (picture pointer) file “C0001I01.PPN” are stored in the clip directory “C0001”.

  Information on the directory CLPR, that is, information on each file constituting a clip placed under the directory CLPR can be found based on the information described in the index table. For example, based on information such as the delta entry array and index entry array in the index table, the system data, video data, and audio data information constituting the clip can be known. Based on this information, each file under the directory CLPR File size can be obtained. The file name can be automatically assigned by the system according to a predetermined rule.

  A file “INDEX.XML” placed directly under the directory PROAV is an index file for managing clip information stored under the directory PROAV. In this example, the file “INDEX.XML” is described in an XML (Extensible Markup Language) format. Each file described above is managed by this file “INDEX.XML”. For example, a file name and a UMID (Unique Material Identifier) conversion table, length information (Duration), a playback order when the entire optical disc 1 is played back, and the like are managed. In addition, video data, audio data, auxiliary AV data, and the like belonging to each clip are managed, and clip information managed by files is managed in the clip directory. The disc information file “DISCINFO.XML” manages information related to this disc. Playback position information and the like are also stored in this file “DISCINFO.XML”. Information described in these files “DISCINFO.XML” can also be obtained based on the above-described index table.

  For the data on the optical disc 1 managed in this way, an external device such as a computer device connected via the communication I / F 126 divides each level of the directory by a predetermined delimiter based on the above-described directory structure, for example. By specifying the file, the recording / reproducing apparatus 100 can be requested to access the data associated with the file.

  At this time, the external device can display the directory structure in various formats. For example, the directory structure can be expressed by the tree structure shown in FIG. However, the present invention is not limited to this, and a clip structure can also be presented using a folder structure used in a GUI (Graphical User Interface) by an OS (Operating System) of a computer apparatus.

  As described above, by managing the clips in the directory structure, for example, in an external device such as a computer device connected via the communication I / F 126, each clip and each data constituting the clip can be handled as one file. The operation of the clip and each data constituting the clip is facilitated.

  As already described, the recording / reproducing apparatus 100 has a communication I / F 134 capable of communication by TCP / IP in addition to the communication I / F 126 as a communication means with the outside. The above-described method for presenting an interleaved MXF file can be similarly applied to an external device connected via the communication I / F 134.

  As described above, according to the first embodiment of the present invention, an index table in which frame position information in a clip is described is sequentially created and cached for access to the optical disc 1, for example, Information on the optical disc 1 is virtually presented to an external device using a cached index table. If the access is made to a part included in the already created index table, the already created and cached index table is presented.

  Therefore, an external device can perform random access to a frame in a clip recorded on the optical disc 1 at high speed if the access is to a part for which an index table has already been created. Further, since the cached index table is held until the clip is closed, the processing based on the index table can be performed efficiently.

  Next, a second embodiment of the present invention will be described. The second embodiment is an example in which the index table creation method according to the present invention is applied when data is partially transferred based on an interleaved MXF file.

  Prior to the description of the second embodiment, partial transfer of data based on an interleaved MXF file will be described in order to facilitate understanding. First, processing for extracting video data to be partially transferred from a file will be described. A partial file transfer process according to an embodiment of the present invention will be schematically described with reference to FIGS. 30 and 31. FIG. Consider the case where partial transfer of a file 400 is performed so that a specified number of frames are displayed from the first frame on the display order for the file 400 shown as an example in FIG. 30A. FIG. 31 is a flowchart schematically showing an example of processing for creating a partial transfer file.

  In the following, the number of frames indicating the display length starting from the display start frame is referred to as duration. Further, the frame section designated by the display start frame and the duration is referred to as a designated display section.

  In step S40, the display start frame 401 and the duration with respect to the display start frame 401 are specified for the file 400 shown in FIG. The display end frame 402 becomes the previous frame by the number of frames specified by the duration with respect to the display start frame 401. When the designated display section is set, a section necessary for performing partial transfer is determined in the next step S41.

  FIG. 30B shows an example of a partial transfer file generated by designating a designated display section for the file 400 shown in FIG. 30A. For a specified display section, all edit units including a frame (picture) necessary for decoding a frame in the specified display section are included in the partial transfer file. For example, if the designated top frame 401 is a frame of a B picture or a P picture, the previous frame in time is required to decode the frame. In this case, an edit unit including a picture temporally prior to the picture corresponding to the designated display start frame 401 needs to be included in the partial transfer file. Similarly, if the end frame 402 is a frame of a B picture, it is necessary to include an edit unit including a picture temporally later than the picture corresponding to the frame in the partial transfer file.

  Note that a section before the designated display section, which is composed of edit units including pictures used for decoding the frames in the designated display section, is called a GOP precharge section. Further, a section after the designated display section, which is composed of edit units including pictures used for decoding the frames in the designated display section, is referred to as a GOP overrun section. In one embodiment of the present invention, a partial transfer file is created including the GOP precharge interval and the GOP overrun interval for these designated display intervals.

  Thus, when the edit unit to be transferred by the partial transfer file is determined, the index table is updated in accordance with the determined content in step S42. For example, as will be described in detail later, the stream offset in the information for each edit unit in the index entry array in the index table is rewritten. Further, the index start position and index duration in the index table are rewritten as necessary. Further, in the next step S43, the values in the partial transfer file of the designated start frame 401 and duration are described in the header 403 as header metadata.

  A partial transfer file is created in step S44 based on the partial transfer section determined in step S41, the index table created in step S42, and the header metadata created in step S43.

  For example, the video data of the partial transfer section determined in step S41 is read from the original file and stored at a predetermined address on the memory. The index table and header metadata created in steps S42 and S43, respectively, are stored on the memory so as to form an image of the partial transfer file together with the video data of the partial transfer section already stored on the memory.

  In the flowchart of FIG. 31 described above, the order of step S42 and step S43 can be interchanged. You may perform the process of step S42 and step S43 in parallel.

  Next, the process of step S41 in the flowchart of FIG. 31 described above will be described in more detail using the flowchart of FIG. In step S50, when a frame is designated by the display order, in the next step S51, the index entry of the coding order corresponding to the display order of the designated frame in the index table is referred to and described in the index entry. The temporal offset to be obtained is obtained.

  In the next step S52, the index entry to be referred to is moved by the value indicated by the temporal offset acquired in step S51. When obtaining an edit unit necessary for decoding the display end frame of the designated display section (step S53), the edit unit corresponding to the index entry of the movement destination moved in step S52 is the edit unit to be obtained. (Step S54).

  On the other hand, when an edit unit necessary for decoding the display start frame of the designated display section is obtained (step S53), the process proceeds to step S55, and the index entry of the movement destination moved in step S52, Get keyframe offset. Then, in the next step S56, the index entry to be referred to is moved by the value indicated by the acquired key frame offset, and the edit unit corresponding to the destination index entry is moved to the designated display section designated in step S50. The first editing unit necessary for decoding the display start frame is set (step S57).

  A more specific example will be described with reference to FIGS. FIGS. 33 and 34 show an example in which an edit unit to be stored in a partial transfer file is obtained for video data having an open GOP structure. It is assumed that the display order and the coding order are started from the number # 0 and are continuous from FIG. 33 to FIG.

  FIG. 33 shows an example of obtaining an edit unit necessary for decoding a display start frame in video data having an open GOP structure. In the example of FIG. 33, the display start frame is designated as frame “B” # 7 included in the GOP having the open GOP structure. In the open GOP structure, this frame “B” # 7 requires a frame belonging to the previous GOP with respect to the GOP to which the frame “B” # 7 belongs. Even in the open GOP structure, the top GOP of the whole is always a closed GOP structure as shown in FIG.

  When the display start frame is designated to the frame “B” # 7 included in the GOP having the open GOP structure, the index entry of the coding order # 7 corresponding to the display order of the frame “B” # 7 is referred to, and the temporal offset Value "+1" is obtained. Then, the index entry is moved by the temporal offset value “+1”, and the key frame offset value “−8” of the index entry corresponding to the coding order # 8, which is the movement destination, is acquired. The edit unit # 0 corresponding to the coding order # 0 indicated by the index entry moved by the key frame offset value “−8” from the index entry corresponding to the coding order # 8 decodes the start frame. It becomes the necessary first editing unit.

  FIG. 34 is an example of obtaining an edit unit necessary for decoding a display end frame in video data having an open GOP structure. In the example of FIG. 34, the display end frame is frame “B” # 19. The index entry of coding order # 18 corresponding to the display order of frame “B” # 19, which is the end frame, is referred to, and a temporal offset value “+1” is obtained. Then, the index entry is moved by this temporal offset value “+1”, and the edit unit # 20 corresponding to the coding order # 20 indicated by the index entry that is the movement destination edits necessary for decoding the end frame. Become a unit.

  FIGS. 35 and 36 show an example in which edit units to be stored in a partial transfer file are obtained for video data having a closed GOP structure. The display order and the coding order are assumed to start from the number # 0 and are continuous from FIG. 35 to FIG.

  FIG. 35 is an example of obtaining an edit unit necessary for decoding a display start frame in video data having a closed GOP structure. In the example of FIG. 35, the display start frame is designated as frame “B” # 7. In the case of the closed GOP structure, the frame “B” positioned before the first frame “I” in the display order is not forward-referenced, and is only backward-referenced by the frame “I” positioned after the frame “B”. Thus, decryption is performed.

  When the display start frame is designated as the frame “B” # 7, the index entry of the coding order corresponding to the display order of the frame “B” # 7 is referred to, and the temporal offset value “+1” is acquired. Then, the index entry is moved by this temporal offset value “+1”, and the key frame offset value “−2” corresponding to the coding order # 8, which is the movement destination, is acquired. The edit unit # 6 corresponding to the coding order # 6 indicated by the index entry moved by the key frame offset value “−2” from the index entry corresponding to the coding order # 8 is for decoding the start frame. It becomes the necessary first editing unit.

  FIG. 36 shows an example of obtaining an edit unit necessary for decoding a display end frame in video data having a closed GOP structure. In the example of FIG. 36, the display end frame is frame “B” # 19. The index entry of coding order # 18 corresponding to the display order of frame “B” # 19, which is the end frame, is referred to, and a temporal offset value “+1” is obtained. Then, the index entry is moved by this temporal offset value “+1”, and the edit unit # 20 corresponding to the coding order # 20 indicated by the index entry that is the movement destination edits necessary for decoding the end frame. Become a unit. As described above, the same result is obtained for the display end frame in the open GOP structure and the closed GOP structure.

  When the edit unit necessary for decoding the display start frame and the edit unit necessary for decoding the end frame are obtained as described above, information on GOPs to which these edit units belong is acquired. Is done. Then, from the GOP to which the edit unit necessary for decoding the display start frame belongs to the GOP to which the edit unit necessary for decoding the display end frame belongs is extracted from the original file in GOP units, Create a transfer file.

  For example, in the example of FIG. 33 showing the display start frame side in the open GOP structure, if the display start frame is the frame “B” # 7 belonging to the second GOP from the top, as described above, it is necessary for decoding. The first editing unit is the frame “I” # 2 in the GOP immediately before the GOP to which the frame “B” # 7 belongs. The frame “B” # 7 uses the frame “P” # 5 decoded using the frame “I” # 2 and the frame “I” # 8 of the GOP to which the frame “B” # 7 belongs. Decrypted. Therefore, the frame by the B picture in the GOP immediately before the GOP to which the frame “B” # 7 belongs is actually unnecessary.

  Here, on the display start frame side, this unnecessary B picture is also stored in the partial transfer file in GOP units.

  Further, in the example of FIG. 34 showing the display end frame side, for example, it is assumed that the display end frame is designated as a frame “I” # 20 that can be decoded only with the corresponding I picture. In this case, according to the processing of the flowchart of FIG. 32 described above, the editing unit necessary for decoding the display end frame is the coding unit # 18 that is the editing unit in which the data of the corresponding I picture is stored. The corresponding editing unit # 18 is obtained. However, since frame “B” # 18 and frame “B” # 19 in the same GOP exist before frame “I” # 20 in the display order, frame “I” # 20 (in coding order) The frame “B” # 18 and frame “B” # 19 (19th and 20th in the coding order, respectively) located after the 18th) also need to be decoded together. The same applies to the case where the display end frame is a frame “P” by a P picture that does not require backward reference.

  As described above, in order to create a partial transfer file by extracting data in units of GOPs, partial transfer including B pictures in which the order of I picture or P picture is switched between display order and coding order on the display end frame side Can be stored in a file.

  However, the present invention is not limited to this, and video data can be extracted from the original file in units of pictures, and a partial transfer file can be created using the extracted pictures. In this case, the edit unit storing the B picture that is unnecessary on the display start frame side is removed, or the B picture whose order is switched between the I picture or P picture, the display order, and the coding order on the display end frame side. It is necessary to appropriately add an edit unit in which is stored.

  Next, the index table update processing in step S42 in the flowchart of FIG. 31 described above will be described in more detail. In each index entry in the index entry array in the index table, since the flag is a unique value for each edit unit, it is unchanged. The slice offset is also unchanged because the partial transfer file is created without the decoding and re-encoding process, and the picture data stored in the edit unit does not change. The temporal offset and key frame offset are unchanged when data is stored in GOP units in the partial transfer file.

  The stream offset is updated for each index entry according to the structure of the essence container stream stored in the partial transfer file. That is, the offset of each edit unit is obtained with reference to the head of the GOP that performs partial transfer, and is set as a new stream offset value.

  In the partial transfer file, the index start position in the index table is updated according to the number of edit units when the number of edit units existing before the index table changes with respect to the original file.

  For example, when the back side including the area managed by an index table is extracted from the original file and stored in the partial transfer file, and the area before the area managed by the index table is not included in the partial transfer file The edit unit number is changed. In such a case, the index start position is updated according to the changed edit unit number.

  The index duration is updated according to the number of edit units when a change occurs in the number of edit units managed in the index table. For example, when an edit unit is extracted from the middle of an area managed by an index table and stored in a partial transfer file, the number of edit units managed by the index table changes. In such a case, the index duration in the index table is updated so as to indicate the number of edits managed by the index table.

  Next, the header metadata update process in step S43 in the flowchart of FIG. 31 described above will be described in more detail. As described above, in the header 403, the display start frame and the duration are described as header metadata. The display start frame is described by a display order in the partial transfer file.

  The effect of describing the display start frame and duration in the header metadata will be described using FIG. 33 described above. As already described, in the example of FIG. 33, when the display start frame is designated as the first frame “B” # 7 of the GOP in the display order in the open GOP structure, the GOP to which the frame “B” # 7 belongs is specified. The frame “I” # 2 of the previous GOP is the first frame necessary for decoding the display start frame “B” # 7. This frame “I” # 2 corresponds to the first edit unit of the GOP in the coding order. In addition, since data is stored in the GOP unit in the partial transfer file, in this example, the GOP immediately before the GOP to which the display start frame “B” # 7 belongs is stored in the partial transfer file. Become.

  If the information for such a designated display section is not described in the header 403, the playback system has no choice but to display from the first displayable frame when playing back the partial transfer file created as described above. When trying to display from the display start frame, it is necessary to cue the display start frame again. For example, in the example of FIG. 9, playback starts from the first frame “B” # 0 in the display order of the GOP immediately before the GOP to which the display start frame “B” # 7 belongs.

  Thus, by describing the information for the designated display section in the header 403 in this way, the reproduction system reads the header 403 in advance when reproducing the partial transfer file, so that it is described in the header metadata. Based on the display start frame and duration information, it is possible to know the section to be displayed in the partial transfer file. As a result, when a partial transfer file is played back, playback can be started directly from the display start frame without playing back the frame before the display start frame, and only the specified section can be displayed easily. Can be done.

  In the second embodiment of the present invention, when the partial transfer file is created as described above, the index table is created as described in the first embodiment. That is, the index table update process in step S42 in the flowchart of FIG. 31 described above is sequentially performed according to the designation of the designated display section.

  More specifically, if the index table included in the partial transfer file generated by designating the designated display section is cached in the RAM 122, update processing is performed on the cached index table. On the other hand, if the index table included in the partial transfer file generated by designating the designated display section is not cached in the RAM 122, a new index is created according to the procedure described with reference to the flowchart of FIG. 19 and FIGS. A table is generated and added to the RAM 122 and cached.

  In this way, by sequentially generating the index table when creating the partial transfer file, the burden on the partial transfer file creation processing is reduced, and processing can be performed at higher speed.

  In the above description, the recording / reproducing apparatus 100 is described as dedicated hardware for reproducing video data recorded on the optical disc 1, but this is not limited to this example, and a general-purpose computer apparatus (for example, a personal computer) ( (Not shown) can also be used as the recording / reproducing apparatus 100. In this case, the function of the recording / reproducing apparatus 100 can be realized by a program installed in the computer apparatus.

  In the above description, the present invention has been described as being applied when an optical disk is used as a recording medium and a clip is recorded with an annual ring structure, but this is not limited to this example. For example, the recording format on the recording medium is not limited to the annual ring structure, and may be another format. Further, the recording medium is not limited to an optical disk, and may be a hard disk drive or a semiconductor memory.

  Further, in the above description, the present invention has been described as being applicable to the interleaved MXF format, but this is not limited to this example. In other words, the present invention can be applied to a system that virtually presents a format unique to a certain recording medium as another format.

It is a basic diagram for demonstrating the decoding process in the case of long GOP. It is a basic diagram for demonstrating an interleave MXF format. It is a basic diagram for demonstrating an interleave MXF format. It is a basic diagram for demonstrating an interleave MXF format. It is a basic diagram for demonstrating an interleave MXF format. It is a basic diagram which shows the bit assignment of an example of the flag in an index entry. It is a basic diagram which shows an example data arrangement | positioning in a disk-shaped recording medium. It is a basic diagram for demonstrating a clip. It is a basic diagram which shows the mode of an example in which annual ring data was formed with respect to the optical disk. It is a basic diagram which shows the data structure of an example in the long GOP of MPEG2. It is a basic diagram which shows the more specific example of the picture pointer table in which picture pointer information is described. It is a block diagram which shows the structure of an example of the recording / reproducing apparatus applicable to one Embodiment of this invention. It is a block diagram which shows the structure of an example of a disk drive part. It is a basic diagram which shows notionally about construction of the interleaved MXF file by the 1st Embodiment of this invention. It is an approximate line figure showing in detail about construction of an interleave MXF file by a 1st embodiment of this invention. It is a basic diagram which shows the structure of an example of a body table. It is a basic diagram which shows the structure of an example of a partition table. It is a block diagram of the recording / reproducing apparatus for demonstrating the production procedure of an interleave MXF file. It is a flowchart which shows the procedure of an example which produces an interleave MXF file. It is a basic diagram which shows roughly the flow of an example of data at the time of creating an interleaved MXF file. It is a basic diagram which shows roughly the flow of an example of data at the time of creating an interleaved MXF file. It is a basic diagram which shows roughly the flow of an example of data at the time of creating an interleaved MXF file. It is a basic diagram which shows roughly the flow of an example of data at the time of creating an interleaved MXF file. It is a basic diagram which shows roughly the flow of an example of data at the time of creating an interleaved MXF file. It is a basic diagram which shows roughly the mode of the interleaved MXF file transferred via communication I / F with the creation of an interleaved MXF file. It is a flowchart which shows creation control of an example of an index table. It is a basic diagram for demonstrating creation of an index table. It is a basic diagram which shows collectively the production | generation of each data at the time of creation of an interleave MXF file. It is a basic diagram which shows the management structure of an example of the data recorded on the optical disk. It is a basic diagram for demonstrating the partial transfer process of a file. It is a flowchart which shows roughly the process of an example which produces a partial transfer file. It is a flowchart which shows an example of a process for determining the area to perform partial transfer. It is a basic diagram which shows the example which calculates | requires the edit unit stored in a partial transfer file about the video data of an open GOP structure. It is a basic diagram which shows the example which calculates | requires the edit unit stored in a partial transfer file about the video data of an open GOP structure. It is a basic diagram which shows the example which calculates | requires the edit unit stored in a partial transfer file about the video data of a closed GOP structure. It is a basic diagram which shows the example which calculates | requires the edit unit stored in a partial transfer file about the video data of a closed GOP structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 10 File 11 Display start file 12 Display end frame 13 Header 100 Recording / reproducing apparatus 102 MPEG encoder 103 Memory controller 104 RAM
105 disk drive unit 106 MPEG decoder 121 CPU
122 RAM
123 ROM
126 Communication interface 132 CPU
133 RAM
134 Communication interface 200 Partition table 201 Body table

Claims (5)

A storage unit;
An index table creation unit ,
The storage unit temporarily stores the index table created by the index table creation unit until the clip recorded on the recording medium is closed,
The index table creation unit creates an index table composed of management information of a plurality of frames of the clip based on information on the recording medium when an output frame is designated,
Next, when the output frame is designated, if the information of the edit unit corresponding to the designated frame is not described in the index table, an index table for managing the edit unit is further created. A playback device. The playback apparatus according to claim 1, wherein information based on the index table is presented for access to the clip recorded on the recording medium . The index table creation unit
2. The partial transfer file is created according to claim 1, wherein the index table corresponding to the predetermined period is updated in accordance with an instruction to transfer a predetermined section of the clip recorded on the recording medium. Playback device. An index table creation step of creating an index table composed of management information of a plurality of frames of a clip based on information on a recording medium when an output frame is designated ;
Temporarily storing the index table created in the index table creating step in the storage unit until the clip recorded on the recording medium is closed ,
Next, when the output frame is designated, if the information of the edit unit corresponding to the designated frame is not described in the index table, an index table for managing the edit unit is further created. A characteristic reproduction method. An index table creation step of creating an index table composed of management information of a plurality of frames of a clip based on information on a recording medium when an output frame is designated ;
Temporarily storing the index table created in the index table creating step in the storage unit until the clip recorded on the recording medium is closed ,
Next, when an output frame is designated, if the information of the edit unit corresponding to the designated frame is not described in the index table, a reproduction method for further creating an index table for managing the edit unit A reproduction program for causing a computer device to execute the above.

Images