HK1069474B - Method for creating, updating, and recording seamless presentation information of moving picture data in a rewritable recording medium - Google Patents

Description

Method for creating, updating and recording seamless display information in rewritable recording medium

Technical Field

The present invention relates generally to a method of creating, updating, and recording seamless presentation (seamless presentation) information of moving picture data in a rewritable recording medium, and more particularly, but not exclusively, to a method of creating seamless presentation information and efficiently updating seamless presentation information without unnecessary information fields when some video objects are removed.

Background

Since the advent of CD (compact disc), optical discs have been widely used, and the demand for optical discs is expected to steadily increase with the spread of DVD (digital versatile disc). The optical disk includes read-only optical disks such as CD-ROM and DVD-ROM, write-once disks such as CD-R and DVD-R, and rewritable disks such as CD-RW and DVD-RAM. The specifications of the standard write/read format DVD-RTRW for rewritable optical discs have not yet been released, and the standardization of DVD-RTRW is in progress.

As a rewritable optical disk such as a DVD-RAM has a very large capacity, a user can store a variety of data such as moving images, still images, audio data, and the like on a single recording medium. Every time a new data file is recorded on a rewritable recording medium, navigation information for locating the data file after recording is created and recorded on the recording medium together with the data file. The recorded navigation information is referenced whenever the associated data file is accessed.

The navigation information on all data files stored on the recording medium is contained in a navigation data table as shown in fig. 1, which is recorded on the recording medium as a single navigation data file. Accessing the recording medium requires loading the navigation data file into the memory, where the navigation data resides at all times. When recording a moving or still image on the recording medium, the area in which the image file is recorded will be determined with reference to the navigation information. Recording an image file is always accompanied by creating management information on the recorded image file and updating a navigation data file so as to include the newly created management information.

The management data attached to the moving picture includes moving picture video object information (M _ VOBI) and moving picture video object display sequence information (cell information or CI for short). It is assumed that one moving picture file is composed of n moving picture video objects (M _ VOB) M _ VOB #1 to M _ VOB # n as shown in fig. 2. Then, n M _ VOBs (M _ VOB #1 to M _ VOB # n in fig. 2) and n CIs (CI #1, CI #2, CI #4 … shown by hatching in fig. 2) corresponding to the n M _ VOBs are created in the same order as when the n M _ VOBs were recorded. The created M _ VOBI and CI are stored in the moving picture a/V file information table (M _ AVFIT) and the initial program chain information table (ORG _ PGCIT), respectively, of the navigation data shown in fig. 1.

When the recording medium is accessed, the navigation data file is read out from the recording medium and loaded to the memory, as previously described. If playback of a moving picture is requested, M _ VOBI and CI associated with the requested moving picture file are read out from M _ AVFIT and ORG _ PGCIT of the navigation data table, respectively. Referring to the obtained M _ VOBI and CI, the requested moving picture file can be located and played back from the recording medium.

As shown in fig. 1, the animation a/V file information table (M _ AVFIT) includes animation a/V file information table information (M _ AVFIT) in which information about M _ AVFIT, such as an end address of M _ AVFIT, is stored, and animation a/V file information (M _ AVFI # 1). The M _ AVFI #1 further includes motion picture a/V file general information (M _ AVFGI) and M _ VOBI, M _ VOBI #1 to M _ VOBI # n in which general information on the M _ AVFI, such as the number of M _ VOBs included in the M _ AVFI, is stored. Each M _ VOBI includes moving picture VOBI general information (M _ VOBIGI) in which an ID code of the relevant VOB is stored, moving picture VOB stream information (M _ VOB _ STI) in which video and audio attributes of the relevant VOB are stored, seamless display information (SMLI) in which information for seamless display of consecutive MOVs (M _ VOB # i and M _ VOB # i +1, i being 1 to n) is stored, and time map information (pi TMAPI) in which information for special playback or time search is stored.

A moving or still image file is recorded as a set of Video Objects (VOBs) on a recording medium. In order to play back moving picture data received and recorded as a continuous stream, it is necessary to seamlessly display the relevant VOB. On the other hand, seamless display is not always necessary for moving image data obtained through a repeated recording-stopping (recording-stop) process. If the continuously inputted image data contains still images and also includes moving images, the image data is classified into a moving picture VOB (M _ VOB) and a still picture VOB (S _ VOB) and recorded. In this case, seamless display between the M _ VOB group and the S _ VOB group is also unnecessary.

When recording received image data on a recording medium, it is necessary to create information as to whether or not to seamlessly display successive VOBs forming the image data so that the information can be used during data playback. This information is recorded in the SMLI shown in the navigation data table of fig. 1.

As shown in fig. 1, the SMLI includes a seamless display flag (SML _ FLG) indicating how the relevant VOB is displayed after the previous VOB is displayed (e.g., 1 indicates that seamless display is required and 0 indicates that seamless display is not required), a display start time of a FIRST video field of the relevant VOB (VOB _ V _ S _ PTM), a display end time of a LAST video field of the relevant VOB (VOB _ V _ E _ PTM), a System Clock Reference (SCR) of a FIRST set of the relevant VOB (VOB _ FIRST _ SCR), a system clock reference of a LAST set of the previous VOB (VOB _ LAST _ SCR), a VOB audio pause time (VOB _ a _ STP _ PTM) representing a stop time of audio at a discontinuity in a PTM description format of RTRW between the current VOB and the previous VOB, and a VOB audio GAP length (VOB _ a _ GAP _ LEN) representing a discontinuous period at a discontinuous point between the current VOB and the previous VOB.

As described in fig. 3, one M _ VOB is composed of a plurality of video object units (M _ VOBU), each of which includes a plurality of video PACKs (V _ PAK), sub-picture groups (SP _ PAK), and audio PACKs (a _ PACK).

The V _ PAK of each M _ VOB is encoded according to the MPEG-2 video encoding method. The first V _ PAK includes a group header, a system header, a packet header and video data as shown in fig. 4A, and each of the other V _ PAKs includes a group header, a packet header and video data as shown in fig. 4B. A System Clock Reference (SCR) and a display time stamp (PTS) required for displaying a video group are recorded in a group header and a packet header, respectively.

The a _ PAK of each M _ VOB is encoded according to one of the following encoding methods: linear PCM encoding as shown in fig. 5A, Dolby (Dolby) AC-3 encoding as shown in fig. 5B, and MPEG-2 audio encoding as shown in fig. 5C. Regardless of the employed coding method, the SCR and PTS are recorded in the group header and the packet header, respectively.

The M _ VOB includes a plurality of top fields (or even fields) and bottom fields (or odd fields) as shown in fig. 6, and a pair of the top fields and the bottom fields constitute one frame. The PTS of the first field of the M _ VOB corresponds to the display start time of the VOB (VOB _ V _ S _ PTM), and the addition of 1/60 seconds to the PTS of the last field corresponds to the display end time of the VOB (VOB _ V _ E _ PTM).

As mentioned earlier, when a moving image is taken through a repeated recording-stopping process or image data includes moving and still image data, it is not necessary to provide seamless display of audio and video data. In this case, VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields in the SMLI are unnecessary because such fields are only used in the seamless display of consecutive VOBs.

In the conventional navigation data structure, each SMLI contains VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields, whether or not the fields are necessary, which unnecessarily increases the amount of navigation data. Also, when some VOBs are removed from the image data, the SMLI of the VOBs subsequent to the removed VOB should be appropriately processed, which is not considered sufficiently.

Disclosure of Invention

It is therefore an object of the present invention to provide a method of creating and recording seamless presentation information required for seamless presentation of continuous video objects of moving image data that reduces the amount of seamless presentation information data obtained as a result.

It is another object of the present invention to provide a method for updating and recording seamless presentation information when some video objects are deleted in recorded moving image data, which enables seamless presentation information data to be efficiently managed by appropriately updating navigation data associated with video objects subsequent to the removed video objects.

The method for creating and recording seamless display information of the invention comprises the following steps: recording the received image data on a recording medium by grouping the data into video objects; determining whether two consecutive video objects are designated to be seamlessly displayed as a pair of video objects; setting a seamless display flag contained in seamless display information of a latter one of the two consecutive video objects according to the determination result, and creating an optional information field in the seamless display information based on a value of the seamless display flag.

According to an aspect of the present invention, a method of creating seamless presentation information of image data in a recording medium by a recording/reproducing apparatus including an optical pickup and a control unit, includes the steps of: recording image data on a recording medium by grouping the image data into objects; determining whether the recorded image data is a still image or a moving image; and creating, by the control unit, seamless display information including time information for displaying each object only when the determining step determines that the recorded image data is a moving image, wherein the seamless display information is information necessary for seamless display of the recorded image data and the time information for displaying each object is to be used for seamlessly displaying two consecutive objects of the recorded image data.

The method for updating and recording seamless display information of the invention comprises the following steps: clearing the video object requested to be deleted; and updating seamless display information of the video object subsequent to the cleared video object.

Drawings

Fig. 1 is a table showing a structure of conventional navigation data for managing image data recorded on a rewritable recording medium;

fig. 2 is a diagram illustrating a process of creating navigation data when recording moving image data on a rewritable recording medium;

FIG. 3 is a diagram showing the structure of the animated video object shown in FIG. 2;

FIGS. 4A and 4B are diagrams illustrating the structure of the video team shown in FIG. 3;

FIGS. 5A, 5B, 5C are diagrams illustrating the structure of the audio group shown in FIG. 3;

fig. 6 is a diagram for explaining a video display start time (VOB _ V _ S _ PTM) and an end time (VOB _ V _ E _ PTM) of a video object;

FIGS. 7A and 7B are diagrams illustrating the structure of seamless display information according to the present invention;

fig. 8 is a schematic view of an optical disc recording/reproducing apparatus embodying the present invention;

fig. 9 is a flowchart showing a method for creating and recording seamless presentation information of moving picture data in a rewritable recording medium of the present invention;

fig. 10 is a flowchart showing a method for updating and recording seamless presentation information of moving picture data in a rewritable recording medium of the present invention.

Detailed Description

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 7A and 7B illustrate seamless presentation information (SMLI) of navigation data according to the present invention.

Fig. 7A depicts an SMLI in which SML _ FLG is 0, indicating that seamless display of consecutive video objects is not required. Such an SMLI is created when moving image data is obtained at one location and is obtained again at another location after a time interval, or is created when moving image data and still image data are continuously received.

Fig. 7B depicts an SMLI where SML _ FLG is 1 indicating seamless display of consecutive video objects is required. When moving picture data is received and recorded as a continuous stream without an additional time gap, the relevant VOB needs to be displayed seamlessly. In this case, an SMLI as shown in fig. 7B is created.

As described in fig. 7A and 7B, the method of creating seamless display information of moving image data of the present invention generates different structures of SMLI depending on the value of SML _ FLG. If the SML _ FLG of the SMLI is 0, VOB _ FIRST _ SCR and VOB _ LAST _ SCR of the SMLI are not required and thus the field will not be created. As a result, VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields are only created when SML _ FLG is 1, thereby reducing the amount of seamless display information contained in the navigation data.

Fig. 8 shows a schematic diagram of an optical disc recording/reproducing apparatus embodying the present invention.

The device includes: an optical pickup 10 for recording/reproducing information to/from a recording medium OD; an analog signal processing unit 20 for filtering and digitizing a high frequency analog signal reproduced by the recording medium OD and converting digital data to be recorded on the recording medium OD into an analog signal; a digital signal processing unit 30 for decoding and encoding digital data and generating a control signal for data synchronism; an a/V data processing unit 40 for decoding audio/video input data, hereinafter abbreviated as a/V data, and encoding the audio/video input signal into a/V data; a control unit 50 that controls general operations of the apparatus in response to user requests; and a plurality of memories M1, M2, M3 for storing temporary data generated at the respective signal processing stages.

When moving image data is recorded on the recording medium OD in the apparatus shown in fig. 8, first the control unit 50 loads the navigation data file recorded on the recording medium OD into the memory M1. Referring to the loaded navigation data, the control unit 50 records image data on the recording medium OD and creates management information on the recorded image data. The created management information is added to the navigation data file loaded in the memory M1.

Moving picture data is recorded on a recording medium as a set of video objects (M _ VOB #1 to M _ VOB # n as shown in fig. 2). Video object information M _ VOBI (M _ VOBI #1 to M _ VOBI # n shown in fig. 2) is created in the same order as M _ VOB. Also, Cell information CIs (Cell #1, Cell #2, Cell #4 … shown in fig. 2) are created in the same order, and the created CIs are sequentially recorded in the initial program chain information table (ORG _ PGCIT) of the navigation data table shown in fig. 1.

It is assumed in fig. 2 that Cell #1, Cell #2 … Cell # n are related to moving image data, and Cell #3 is related to still image data. Then VOBI, M _ VOBI #1 and M _ VOBI #2 are information on M _ VOB #1 and M _ VOB #2 continuously recorded on the recording medium. The SML _ FLG of the SMLI of VOBI #2 is thus set as shown in fig. 7B and the FIRST SCR of the M _ VOB #2 and the LAST SCR of the previous VOB (M _ VOB #1) are recorded in the VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields of the M _ VOB #2, respectively.

In contrast, M _ VOB #2 and M _ VOB #3 are not continuously recorded because a still image video object (not shown in fig. 2) is recorded therebetween. Therefore, the M _ VOB #3 does not need to be displayed seamlessly after the display of the previous still picture video object. As a result, the SML _ FLG of the SMLI of M _ VOBI #3 is cleared and the SMLI does not contain VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields, as shown in fig. 7A.

Assuming that the user records moving image data and continues to record the moving image data after a time interval, the SMLI of the FIRST M _ VOBI of the newly recorded image data does not include the VOB _ FIRST _ SCR and the VOB _ LAST _ SCR fields, as shown in fig. 7A, because the SML _ FLG of the SMLI is 0. The decision as to whether to create a field or whether to set the SML _ FLG is made by the control unit 50.

Even if moving image data continues to be recorded after a time interval, if a user requests a seamless display, the originally recorded data and the newly recorded data can be continuously displayed. The control unit 50 detects whether or not the user selects a recording mode requiring seamless display of moving image data while continuing recording. If so, the control unit 50 sets the SML _ FLG of the FIRST M _ VOBI of the newly recorded image data and generates the SMLI having VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields. The FIRST SCR of the current VOB is recorded in VOB _ FIRST _ SCR and the LAST SCR of the previous VOB is recorded in VOB _ LAST _ SCR.

If a request to clear one VOB is received, assuming VOB # i, the control unit 50 clears the VOBI and CI corresponding to the VOB from the recording medium and clears the VOB. Then, the control unit 50 updates the navigation information of the M _ VOB after the removed VOB. In particular, the SML _ FLG of M _ VOBI # (i +1) is cleared and VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields are removed from the VOBI. In addition, VOB _ a _ STP _ PTM and VOB _ a _ GAP _ LEN fields are updated.

A method of creating and recording seamless presentation information of moving image data on a rewritable recording medium according to the present invention is explained in detail below with reference to a flowchart shown in fig. 9.

If the recording of the moving image data is requested, the control unit 50 starts executing the recording control program to load the navigation data file from the recording medium to the memory M1 (S31). Also, the control unit 50 controls the a/V data processing unit 40, the digital signal processing unit 30, and the analog signal processing unit 20 so that the moving image obtained from the external device is recorded on the recording medium OD (S33).

The input data is recorded as a series of M _ VOBs on the recording medium OD. The control unit 50 generates M _ VOBI corresponding to the VOB and adds the M _ VOBI to the M _ AVFIT of the navigation data loaded in the memory M1. The SML _ FLG of the FIRST M _ VOBI is 0 and the SMLI does not contain VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields because the FIRST VOB does not need to be displayed seamlessly together with the LAST M _ VOB of the previously recorded picture data. Also, the control unit 50 generates a CI corresponding to the recorded VOB and adds it to ORG _ PGCIT of the navigation data stored in the memory M1 (S35).

Next, in step S37, the control unit 50 detects whether the current operation mode is for recording still image data (S37). If not, the control unit 50 controls each system component so that the moving image input is recorded on the recording medium OD as in step S33 (S39). The received image data is grouped into M _ VOBs and an M _ VOBI for the M _ VOB is created and added to the M _ AVFIT of the navigation data in the memory M1. The M _ VOB needs to be seamlessly displayed together with the previous M _ VOB because the moving picture data is continuously obtained after the previously obtained moving picture data is recorded. Therefore, unlike step S35, the SML _ FLG of the newly created M _ VOBI is 1, so that VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields are created and recorded in the SMLI. Also, the control unit 50 generates and adds CI regarding the recorded VOBs to ORG _ PGCIT of the navigation data stored in the memory M1 (S41).

In step S43, the control unit 50 detects whether the end of the recording mode is requested. If not, program control returns to step S37, where it is detected whether recording of still image data is requested. Unless requested, program control returns to step S39 and the above process is repeated. If the request is accepted, it goes to step S47 to start recording of the input still image data. As in the case of moving image data, still image data is recorded as a series of VOBs. After the first VOB of the input image data is recorded, the control unit 50 generates and adds the S _ VOBI associated with the first VOB to the S _ AVFIT of the navigation data loaded in the memory M1. Also, the control unit 50 generates and adds CI regarding the recorded VOBs to ORG _ PGCIT of the navigation data stored in the memory M1 (S49). The control unit 50 checks whether the end of the recording mode is requested (S51). If not, program control returns to step S53, and there is detected whether or not recording of moving image data is requested. Unless requested, program control returns to step S47 and the above process is repeated. If the request is accepted, program control returns to step S33 and repeats steps S33 through S35. In this case, the first VOB of the new moving picture data does not need to be displayed seamlessly, so that the VOBI related to the VOB includes the SMLI, the SML _ FLG of which is 0 as shown in fig. 7A.

Meanwhile, having requested the end of the recording mode at step S43 or S51, the control unit 50 copies the navigation data in the memory M1 to the recording medium OD and completes the control operation (S45).

A method of updating and recording seamless presentation information of moving image data on a rewritable recording medium according to the present invention will be explained in detail as follows with reference to a flowchart shown in fig. 10.

In response to the user' S request, the control unit 50 starts executing the clear control program to load the navigation data file from the recording medium to the memory M1 (S61). It is assumed that VOB # i is to be cleared. The control unit 50 reads out navigation information VOBI # i related to VOB # i from the M _ AVFIT or S _ AVFIT. Referring to this information, the control unit 50 removes the VOB # i from the recording medium OD.

Subsequently, the control unit 50 removes VOBI # i associated with the deleted VOB # i from the M _ AVFIT or S _ AVFIT and removes CI associated with the deleted VOB # i from the ORG _ PGCIT.

The control unit 50 accesses M _ VOBI # (i +1) to clear the SML _ FLG of the SMLI, removes VOB _ FIRST _ SCR and VOB _ LAST _ SCR fields, and updates the VOB _ a _ STP _ PTM and VOB _ a _ GAP _ LEN fields (S67). Since the M _ VOB # i is cleared from the recording medium, continuity between the M _ VOB # (i +1) and the M _ VOB # (i-1) cannot be maintained and seamless display is not required. This is why the SML _ FLG of M _ VOB # (i +1) is cleared.

In step S69, the control unit checks whether the purge mode is ended. If not, program control returns to step S63. If so, the control unit 50 copies the navigation data in the memory to the recording medium, thereby completing the purge control routine (S71).

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (5)

1. A method of creating seamless presentation information for enabling seamless presentation of image data in a recording medium by a recording/reproducing apparatus including an optical pickup and a control unit, comprising the steps of:

recording image data on a recording medium by grouping the image data into objects;

determining whether the recorded image data is a still image or a moving image; and

only when the determining step determines that the recorded image data is a moving image, seamless display information including time information for displaying each object is created by the control unit, wherein the seamless display information is information necessary for seamless display of the recorded image data, and the time information for displaying each object is to be used for seamlessly displaying two consecutive objects of the recorded image data.

2. The method of claim 1, wherein the seamless presentation information is included in navigation information attached to each object.

3. The method of claim 2, wherein the navigation information includes a seamless display flag indicating whether a corresponding object is displayed seamlessly with a previous object.

4. The method of claim 1, wherein the seamless display information comprises at least one field corresponding to a system clock reference, wherein the time information is based on the system clock reference.

5. The method of claim 4, wherein the at least one field corresponding to a system clock reference comprises a last system clock reference field of the former of two consecutive objects and a first system clock reference field of the latter of two consecutive objects.