This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-306081, filed Oct. 20, 2004 the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a recording method for a WORM recording medium (e.g., a write-once medium such as a DVD-R disc) and, more particularly, to a method and apparatus for efficiently using a write-once medium which has limited storage capacity.
2. Description of the Related Art
As a video recording format of a digital versatile disc (DVD), a DVD video format used in DVD software in cell (or package) sales, or a DVD-VR format used in a DVD recorder to perform an editing process is available. Conventionally, the DVD-VR format is mainly used on a DVD-RAM or DVD-RW (Jpn. Pat. Appln. KOKAI Publication No. 9-259538).
These DVD-RAM and DVD-RW are rewritable media to advantageously perform the editing process. However, the unit costs of these media are relatively high. In contrast to this, the cost of the DVD-R is relatively low. Conventionally, by making a point of playback compatibility with a DVD player, information has been mainly recorded on the DVD-R in the DVD video format. However, a recording process on the DVD-R in the DVD-VR format is also officially approved as a DVD forum standard.
In a recording method according to an embodiment of the present invention, for example, there is provided a recording method for executing digital recording on a write-once medium having a recording area which is configured to include a plurality of recording zones between a lead-in side and a lead-out side. In this method, when a plurality of recording zones (Rzones 3, 4, and 5) are to be sequentially formed from the lead-in side to the lead-out side, in at least one (Rzone 4) of the plurality of recording zones, first digital data including a first digital content (<7> real-time data 2) and first management information (<8> changed file/VAT_ICB) is recorded (steps ST804 to ST808). Next, second digital data including a second digital content (<10> real-time data 3) and second management information (<11> changed file/VAT_ICB) is recorded without closing the one zone (Rzone 4) (NO in step ST800c) (steps ST804 to ST808), and the one zone (Rzone 4) is then closed (<12> Rzone close; step ST809).
On a write-once medium such as a DVD-R, picture information can be recorded in a video recording format such as a DVD-VR format using a plurality of recording zones.
A recording zone (Rzone) close process need not always be executed for every video recording process. Since this process can be arbitrarily executed, the capacity of a management area (RMA) can be saved. Alternatively, the integrity of important data (e.g., a video recording program that a user wants to store) can be ensured by log management.
An embodiment of the present invention will be described below with reference to accompanying drawing.
The video recording apparatus shown in
The video recording apparatus shown in
Note that when directly receiving a directly compressed digital video signal and digital audio signal, encoder 50 can directly supply the compressed digital video signal and digital audio signal to formatter 51. This encoder 50 can also directly supply the digital video signal and digital audio signal which are converted into the analog video signal and analog audio signal to video mixing unit 71 and audio selector 76. The video encoder in encoder 50 converts the digital video signal into a digital video signal compressed at variable bit rate according to the MPEG2 or MPEG1 standard. The digital audio signal is converted into a digital audio signal or linear PCM digital audio signal compressed at fixed bit rate on according to the MPEG or AC-3 standard.
When the sub-picture signal is output from AV input unit 41 (for example, when a sub-picture signal is output from a DVD video player with an independent output terminal), or when a DVD video signal in such a data structure is broadcast and received by TV tuner 42, the sub-picture signal in the DVD video signal is encoded (compressed by runlength encoding) by the sub-picture encoder. The encoded sub-picture signal becomes a sub-picture bitmap. The encoded digital video signal, digital audio signal, and sub-picture data are converted into packs, i.e., a video pack, audio pack, and sub-picture pack by formatter 51. These packs are then collected and converted into packs in a format (DVD video format) defined by the DVD video standard, or a format (DVD-VR format) defined by the DVD-recording standard.
The apparatus shown in
Microcomputer block 30 includes a microprocessing unit (MPU) or central processing unit (CPU), a ROM written with control programs and the like (e.g., firmware for controlling the apparatus as shown in
Of the execution results of MPU 30, the contents that a user should know are displayed on display 43 in the picture data recording/playback apparatus, or displayed on a monitor display by on-screen display (OSD). Microcomputer block 30 has key input unit 44 which supplies an operation signal for operating this apparatus. This key input unit 44 corresponds to, e.g., operation switches arranged on the main body of the video recording apparatus, or a remote-controller device. Note that input unit 44 may be a personal computer connected to the video recording apparatus according to the embodiment of the present invention, via a wired communication, wireless communication, optical communication, infrared communication, or the like. In each arrangement, when the user operates this key input unit 44, for example, the input picture/audio signal can be recorded, the recorded contents can be played back, or the video recorded contents can be edited.
Note that microcomputer block 30 controls disc drive unit 1002, hard disc drive unit 2001, data processor 1003, encoder 50, and/or decoder 60 at timings based on the timing data from a system time clock (STC) 38. The video recording/playback operations are generally executed in synchronism with time clocks from STC 38, but other processes may be executed at timings independent of STC 38.
Decoder 60 comprises a separator for separating and extracting the respective packs from DVD format signals with the pack structure, a memory used in executing pack separation and other signal processes, a V decoder for decoding main picture data (the contents of video packs) separated by the separator, an SP decoder for decoding sub-picture data (the contents of sub-picture packs) separated by the separator, an A decoder for decoding audio data (the contents of audio packs) separated by the separator. This decoder 60 also comprises a video processor for appropriately mixing decoded sub-picture data with the decoded main picture to superpose sub-picture data such as menus, highlight buttons, superimposed dialogs, and the like on the main picture, and outputting them.
The output video signal from decoder 60 is input to video mixing unit 71. This video mixing unit 71 mixes the text data, and is connected to a line which directly captures the signals from TV tuner 42 and AV input unit 41. Video mixing unit 71 is also connected to frame memory 72 serving as a buffer. When an output from video mixing unit 71 is an analog output, the information is externally output via interface 73. If the output from video mixing unit 71 is a digital output, the information is externally output via digital-to-analog converter 74.
The output audio signal from decoder 60 is converted to the analog output audio signal by digital-to-analog converter 77 via selector 76, and then externally output. Audio selector 76 is controlled in accordance with the select signal from microcomputer block 30. Accordingly, when directly monitoring the digital signals from TV tuner 42 and AV input unit 41, this selector 76 can also directly select the signal which has passed through encoder 50.
Note that, formatter 51 in encoder 50 generates segmentation information during video recording, and periodically sends it to the MPU of microcomputer block 30 (information in GOP head interrupt or the like). The segmentation information includes the number of packs of VOBUs, the end address of I-picture data from the head of the VOBU, the playback time of the VOBU, and the like. At the same time, information from the aspect information processing unit is sent to the MPU at video recording start time. The MPU then generates VOB stream information (STI). Note that the STI stores resolution data, aspect data, and the like to initialize each decoder on the basis of the information.
In the apparatus shown in
Data processor 1003 receives each VOBU data from the formatter of encoder 50, and then supplies each CDA data to disc drive unit 1002 or hard disc drive unit 2001. The MPU of microcomputer block 30 generates management information required for playing back the recorded data, and recognizes the command representing the end of data recording. After that, the generated management information is sent to data processor 1003. With this operation, the management information is recorded on the disc. Therefore, during encoding, the MPU of microcomputer block 30 receives data unit information (e.g., segmentation information) from encoder 50. At the recording start time, the MPU of microcomputer block 30 also recognizes the management information (file system) read from the optical disc and hard disc, recognizes the unrecorded area on each of the discs, and sets the data recording area on the disc via data processor 1003.
Next, referring to
The information pack corresponds to, e.g., an RDI pack in the DVD video recording (DVD-VR) standard. In this case, this pack includes information indicating the playback start time of the first field of a VOBU to which this pack belongs, information indicating the recording time of a VOBU, manufacturer information (MNFI), and the like. The information pack can also include display control information (DCI) and copy control information (CCI). The display control information indicates aspect ratio information, sub-title mode information, film camera mode information, and the like. The copy control information includes copy enable information or copy inhibition (disable) information.
The picture pack which is obtained by compressing the video data by MPEG2 standard includes a pack header, packet header, and video data. The audio pack which is obtained by processing the audio data by, e.g., linear PCM, MPEG, or AC-3 standard includes a pack header, packet header, and audio data.
Next, the management information will be described. In the management information, original title (program) information serving as information (playback order information) for managing the playback order of the real picture data is defined. This information corresponds to, e.g., the program in the DVD-VR standard. In each of the pieces of original title information (or program information), reference information is defined and linked to the real picture data information serving as the information pertaining to the real picture data to be played back. The pieces of information correspond to a cell, video object information (VOBI), and the like in the DVD-VR standard. As described above, the original title (program) has the information (playback order information) for managing the playback order, and its own real picture data. During video recording, this title is generally generated.
In contrast to this, in some cases, an original title (program) includes only information (playback order information) for managing the playback order. This is play list information which corresponds to a play list in, e.g., the DVD-VR standard. This play list information does not have its own real picture data. As shown in
Time map information is described in the real picture data information. This time map information designates a partial area included in the real picture data stream corresponding to the real picture data information. A logical address specifies the link from the original title information of management information or the reference information of play list information to the real picture data information. Also, the link from the time map information to the real picture data stream and its partial area is implemented on the basis of a real picture data stream number, the number of partial areas in this stream, an entry number for each of the partial areas, and the logical address to each of the partial areas. In this arrangement, this apparatus can cope with not only normal playback of the video recorded picture data, but also special playback such as fast-forward/slow playback and fast-reverse playback, and a scene searching process.
An operation according to the embodiment of the present invention will be described below from
In the video recording apparatus according to the embodiment of the present invention, not only the rewritable DVD-RAM disc and DVD-RW disc but also the DVD-R disc serving as a write-once medium can be used. The format for performing the video recording process on each of these DVD discs is not uniquely fixed to each type of the DVD disc. For example, the video recording process can be performed on the DVD-R in the DVD-VR format or the DVD video format.
In the following description, assume that the video recording apparatus according to the embodiment of the present invention serves as a hybrid video recording device which has two types of video recording media, i.e., the DVD and HDD, as shown in a block diagram in
In addition to this, in the video recording apparatus according to the embodiment of the present invention, the partial area in the video recorded title is called a chapter. For example, when video recording is executed in the DVD-VR format, an entry point (EP) defined in the DVD-VR standard in the title is used as the mark of a boundary between the chapters. That is, a zone sandwiched between a given EP and the next EP in the title is called the chapter. Note that the start point and end point of the title serve as chapters irrespective of the presence/absence of the EPs. Hence, in some cases, an EP may not be present at the start point of the first chapter of a title.
First, VR_MANGR.IFO is navigation data for the original title (program) and play list. This navigation data corresponds to the management information shown in
VR_MANGR.BUP is a backup file of the above-described VR_MANGR.IFO. Since this VR_MANGR.BUP is an option in the standard, it is not always present. However, when using this VR_MANGR.BUP, the contents of this file must be the same as VR_MANGR.IFO.
Alternatively, VR_MOVIE.VRO is an AV (Audio Visual) data file of a recorded moving image, and corresponds to the real picture data shown in
These VR_MOVIE.VRO, VR_STILL.VRO, and VR_AUDIO.VRO files are not present when the DVD disc is initialized. These files are generated when the video recording process is actually executed, to record the picture data and audio data. Note that these three different files need not be always present. For example, in some cases, in a video recording apparatus without any still image recording function or postrecording function, VR_STILL.VRO and VR_AUDIO.VRO files are not present.
The file defined by Ver1.1 in the DVD-VR standard has been described above. In addition to this, in order to increase the operability and add functions in the video recording apparatus, an information file unique to the video recording apparatus can be generated. In this case, these unique information files are not stored under DVD_RTAV. These unique information files are stored immediately under the root directory, or under a unique sub-directory generated under the root directory.
More specifically, for example, by the operation of a cursor key and decision key of a remote-controller device (not shown), the user can select a flag (for example, a flag “11”; default setting) indicating important contents, or a flag (for example, a flag “01”, “10”, or “00”) indicating that the capacity savings of an available disc are more important than the reliability of video recording. The flag selected by the user is temporally stored in the memory (e.g., work RAM 31) in MPU 30 shown in
Alternatively, when the user wants to select the flag indicating that the capacity savings of an available disc are more important, the user can select the flag (“00”) indicating that “the zone (Rzone) for the video recording process is not closed at the end of the recording process” (always NO in step ST800c unless the user outputs a command to close the zone). The user can also select the following flag described in detail, in addition to these flags.
That is, by using a user menu or the like, the user can select the flag (“01”) indicating that “the zone (Rzone) for the last video recording process is closed every n times of video recording end processes” where n is an integer equal to or more than 1. The user can also select the flag (“10”) indicating that “the zone (Rzone) for the last video recording process is closed every n times of video recording end processes when the remaining amount of the available disc is m % (e.g., when only 30% of the unused disc capacity remains)” where m is an integer of 1 to 99. Note that the values of n and m can be arbitrarily initialized by the user using the remote-controller device, or determined in advance as default setting by the apparatus shown in
After setting one of the above-described flags (or after selecting the default setting “11” without any operations), when the user presses the video recording button of the remote-controller device (not shown), or when the reservation video recording process is started by a video recording reservation timer (not shown) (YES in step ST800b), a video recording start request is called (step ST800). Next, the remaining amount of the recording area for the video recording process is confirmed (step ST801). In the next step ST802, before the video recording process is actually started, it is determined whether the remaining amount is sufficient for performing the video recording process, and the flow branches. If it is determined that the video recordable remaining amount is substantially 0 (The remaining amount need not be strictly limited to 0. The remaining amount can be practically treated as 0 when the remaining amount completely becomes 0 after a few minutes from the start of video recording), a series of processes end without the subsequent video recording processes.
Alternatively, if the remaining amount for the video recording process is not 0, it is determined whether the zone is closed at that time (step ST800d). If the zone is closed (YES in step ST800d), a zone (Rzone) for recording AV data (real-time data) as shown in
Note that in the processes from step ST804 to step ST807, mainly, the video is recorded, and the remaining amount is checked. In these processes, the remaining amount is sequentially checked while video recording. Since the video recording process and the remaining amount checking process are switched every very short time, these processes are assumed to be concurrently performed in broad perspective. That is, in step ST804, the video recording process is performed. In next step ST805, the amount of data generated by video recording is subtracted from the remaining amount of the recording area. Note that the generated data amount by video recording is also subtracted from the second size which is concurrently stored. Next, in step ST806, it is monitored whether a video recording stop request is called. For example, this video recording stop request includes a manual video recording stop request by user's direct operation, a reservation video recording stop request by timer setting, and a reservation video recording interruption request by user's operation. When it is determined that the video recording stop request is called, the flow skips step ST807, and advances to step ST808. When it is determined that the video recording stop request is not called, the flow advances to step ST807.
In step ST807, the remaining amount obtained by subtracting the code amount generated by video recording in step ST805 is checked. After that, it is determined whether the remaining amount for continuing the video recording process, to branch the flow. If it is determined that the remaining amount is 0, the flow advances to next step ST808. Alternatively, if it is determined that the remaining amount is not 0, the flow returns to step ST804. The processes in steps ST804 to ST807 are repeated to continue the video recording process. In step ST808, assuming that the remaining amount is 0, or that a video recording stop request is called, the video recording process stops, and then the series of processes ends.
Next, it is determined whether the zone for the sequence of the video recording processes is closed (step ST800c). This determination is executed in accordance with the flag (“11”, “01”, “10”, or “00”) set in step ST800a. That is, if the flag is “00”, the video recording zone is not closed even when the video recording process is stopped in step ST808. The flow then returns to step ST800b. (Note that even when the flag is “00”, the video recording zone is closed if the user designates to close the zone by the remote-controller device (not shown).) Alternatively, when n=2 and the flag is “01”, the zone is not closed in the first video recording process in steps ST800 to ST808 (NO in step ST800c), but the zone is closed in the second video recording process (YES in step ST800c, step ST809).
The above-described “the zone close process executed every n times of recording processes” can be implemented by the following processes. A counter (register) (not shown) which presets the numerical value of n in MPU 30 shown in
Furthermore, assume that n=5 and m=30, and the flag “10” is selected. When the remaining amount is 31% or more, the video recording zone is always closed in step ST809 upon stopping the video recording process in step ST808. Alternatively, when the remaining amount is 30% or less, the zone is not closed (NO in step ST800c) in the first to fourth video recording processes of steps ST800 to ST808 (unless the user designates to close the zone). In the fifth video recording process, the zone is then closed (YES in step ST800c, ST809). (Note that it can be confirmed whether the remaining amount m is 30%, in step ST807 or ST801.) When the flag set in step ST800a is “11”, regardless of the numerical values of n and m, the video recording zone is always closed after the video recording process ends in step ST808.
With this operation, the series of video recording processes in the zone ends. After the video recording process ends and the video recording zone is closed (YES in step ST800c), in step ST809, the management information corresponding to the video recording contents (the VR_MANGR.IFO file and its backup file .BUP in
For example, according to an example (DVD-VR format recording on the DVD-R disc) shown in
Similarly, when the sequence of video recording processes in steps ST804 to ST807 shown in
Note that when initializing the DVD-R disc having a recording area as shown in
The outline of the above-described processes (
Note that if the disc to be used is a rewritable medium such as a DVD-RAM or DVD-RW, when changing the recording contents by the edit process, target data can be updated and rewritten on the disc. Alternatively, on a write-once medium such as a DVD-R, even when a part of a given file is changed upon changing the recording contents on the disc, data must be recorded again in the unrecorded area on the disc. That is, when the edit process is performed, the updated data is not overwritten, but incrementally written. In this case, many pieces of management information such as file management information, parent directory information linked with the file management information, parent directory information of the above parent directory information, and the like must be reconstructed, thus greatly reducing efficiency.
In order to reduce the inefficiency, when data is recorded on the DVD-R by incremental write, a special address conversion table called a virtual allocation table (VAT) is assumed to be used in accordance with the UDF standard. By using this table, when changing the recording contents of the disc, only the changed data and the VAT must be recorded. Hence, an enormous amount of data such as the linked parent directory information need not be changed and incrementally written. In
As shown in
That is, a descriptor tag is stored at the head byte position=0. This tag includes two types of tags: one is a volume structure descriptor tag defined by the UDF; and the other is a file structure descriptor tag defined by the UDF. In the DVD-R file structure, virtual allocation table (VAT) and virtual allocation table information control block (VAT_ICB) are recorded in an incremental recording mode. The following contents are allocated to a virtual address in the incremental recording mode. That is, the virtual address=0 is used for the file set descriptor, and the virtual address=1 is used for the ICB root directory. Then, the virtual addresses=2 to 255 are allocated for the file entries of a file recorded in the DVD_RTAV directory or under the DVD_RTAV directory. Since the log information (VAT_ICB with VAT) including these contents is provided at the end of each of the zones, the recorded contents of each of the zones can be managed.
FIGS. 7(a) to 7(c) are views for explaining the outline of the process for, when a mechanical damage is generated on the DVD-R disc during video recording in the DVD-VR format, reusing the disc which is unusable by damage.
After loading the disc (DVD-R) to disc drive unit 1002 shown in
When the flow advances to the log information detection process, first, disc information including the log information (VAT_ICB with VAT shown in
If this obtained last address (e.g., Px1) in the zone has log information (YES in step ST26), it is checked whether the log information is physically valid (e.g., whether the correction failure ECC error does not occur) (step ST28). If the log information is physically invalid (NO in step ST28), the immediately preceding information is read out in step ST32. If the log information is physically valid (YES in step ST28), it is checked whether the readout log information is logically valid (e.g., whether the pieces of file name information are respectively present at byte positions BP of VAT ICB with VAT shown in
In FIGS. 7(a) to 7(c), the above-described processing sequence will be summarized as follows. That is, on a DVD-R disc (write-once medium), as shown in
As described above, on the DVD-R disc which is unusable due to damage, a new video recording process can be performed in zones subsequent to zone 3 (the unusable DVD-R disc can be reused).
FIGS. 12(a) to 12(c) are views showing how to form a plurality of zones (a plurality of Rzones), and how to use management information (RMA) of a medium corresponding to the recording process, when the recording process is performed on the write-once medium upon initialization. FIGS. 12(a) to 12(c) show the state in which Rzone is closed (the recording zone is closed) on an optical disc recording medium (e.g., a DVD-R disc) recording real-time data (e.g., TV broadcast video recording data).
Upon formatting (initializing) the optical disc recording medium, as shown in
After these processes, when the picture (the data such as digital broadcast) is recorded, as shown in
Originally, the check point is ideally formed for each recorded picture data (in other words, the zone is closed every video recording end process). However, the recordable capacity is limited in the RMA area on the optical disc recording medium. Hence, when the RZone close process is frequently performed to completely use the RMA area, the recording medium cannot record any more picture data even if the volume space has a free capacity on the recording medium. In order to avoid such a problem (i.e., in order to suppress the reduction of the RMA area), the frequency of the RZone close process can be arbitrarily set. This process for “arbitrarily setting the frequency of the RZone close process” corresponds to step ST800a and ST800c shown in
Upon using the log management (log information shown in
In order to reduce the probability that the medium cannot be used due to the above-described error, the RZone close process is always performed when recording important real-time data (the flag is set to “11” in step ST800a shown in
First, the initialization process is designated by the user using the remote-controller device or the like (not shown) (step ST40). “RZone#n last recording address (reference symbol #n denotes the number of the last recorded zone)” in the RMA area on the disc is read out to calculate the position of “recorded VAT_ICB (in
(1) A failure portion on a write-once medium which is unusable due to a mechanical error in use is repaired to avoid the failure portion from being used. After that, video recording can be performed in an unused area, and the write-once medium which is unusable because of the mechanical error can be reused.
(2) When a copy-once digital broadcast program is video-recorded on an HDD, and the video-recorded contents are sequentially moved to a DVD disc, the video recorded contents are inhibited from moving to a DVD-R disc in DVD video format. However, the video recorded contents can be moved to the DVD-R disc in DVD-VR format. When the contents are to be moved from an HDD in DVD-VR format, in some cases, 1+⅓ discs are required because only one DVD-R disc cannot record all the program contents. In this case, the DVD-R disc (with a recording amount smaller than that of a new disc) which is made usable (or initialized) by the present invention can be used for moving and video recording the contents, as the ⅓ disc.
(3) The RMA area on the optical disc recording medium is reduced in proportion to the number of times of the RZone close processes (the total number of times of the close processes of the recording zones, or the total number of the recording zones). Since the RZone close process is arbitrarily performed on the basis of user setting, the reduction of the RMA area (or a portion of the volume space) on the optical disc recording medium can be suppressed.
(4) When recording data on the optical disc recording medium, by closing RZone, information (e.g., Last recorded address of RZone#n) in the RMA area is used as the check point for detecting VAT_ICB, thereby performing log management.
(5) Since the check point is intentionally set in the important data (that is, the important video recording zone must be temporally closed), even when the write error occurs (or even when an error occurs after writing), the disc can be returned to the state before the occurrence of an error by log management.
(6) Since RZone is intentionally closed after generating the root directory (in the state shown in
The present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit and scope of the present invention in the present or future phase on the basis of available techniques at that time. In addition, the embodiments can be appropriately combined as much as possible as needed. In this case, a combined effect can be obtained. Furthermore, the embodiment incorporates inventions of various phases, so various inventions can be extracted by appropriately combining a plurality of disclosed components. For example, even when an invention is extracted by omitting several components from the all components disclosed in the embodiment, the remaining arrangement can be extracted as the invention.
Number | Date | Country | Kind |
---|---|---|---|
2004-306081 | Oct 2004 | JP | national |