Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
2001-07-24
2002-04-09
Boccio, Vincent F. (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C386S349000
Reexamination Certificate
active
06370325
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to an optical disc recording apparatus, a computer-readable recording medium recording a file management program, and an optical disc.
(2) Description of the Prior Art
Recently, recording mediums such as magneto optical discs (MO) have been widely used for recording data to be read by computers. Currently, practical uses of DVD (Digital Versatile Disc)-RAM discs are waited for due to general expectation that DVD-RAMs will become a main recording medium of the next generation.
In conventional MOs, like HD (Hard Disc) or FD (Flexible Disc), the minimum unit in accessing data on discs is “sector” having several kilobytes. Each file is recorded in one or more sectors.
Reading and writing of files from/onto discs are executed by computers as functions of a file system which is a part of operating systems (OS). A file system is defined, for example, in ISO/IEC13346.
According to a conventional technique, for example, when recording a file of 200 KB onto a recording medium with 2 KB-sectors, computers must find 100 unassigned sectors on the recording medium. The 100 unassigned sectors need not be physically consecutive. For example, when four separate groups respectively having 30, 30, 30, and 10 unassigned sectors are found on the recording medium, the file is divided into the four groups of sectors. Each part of the file recorded in each group of sectors, namely each group of consecutive sectors, is called “extent”.
In such a conventional technique, files can be divided and recorded into a plurality of extents. This provides a merit that all the sectors on a recording medium can be used efficiently even after recording and deleting of files on the medium are repeated a number of times.
However, conventional recording mediums and file systems have a problem that uninterrupted reproduction of audio/video data (hereinafter referred to as AV data) recorded on the recording mediums cannot be ensured.
More specifically, when recording and deleting of files on a recording medium are repeated several times, the AV data may not be recorded in consecutive sectors. The AV data may be divided and recorded into a plurality of extents, as described above. When this happens, the reproduction apparatus cannot achieve uninterrupted reproduction of the AV data due to a seek operation of an optical pickup that occurs as the optical pickup moves between the plurality of extents.
For example, when a seek occurs between a sector at the innermost periphery and a sector at the outermost periphery of a disc, the seek time amounts to several-hundred milliseconds. In case of moving images, such a seek of several-hundred milliseconds interrupts reproduction since reproducing 30 frames per second is required for reproduction of moving images.
As described above, uninterrupted reproduction may not be ensured by conventional file systems. This is especially a serious problem for mass storages such as DVD-RAM on which, like VTR, a plurality of pieces of AV data (e.g., TV programs) can be recorded, edited, and deleted.
Here, it should be reminded that recording mediums can also record computer data, as well as AV data. Accordingly, particular attention should be paid on how to efficiently store both types of data on a disc.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an optical disc recording apparatus, a computer-readable recording medium recording a file management program, and an optical disc which ensure uninterrupted reproduction of AV data and record various types of data including AV data together and efficiently.
The above object is achieved by an optical disc recording apparatus for recording a video object on an optical disc, where a recording area of the optical disc is divided into a plurality of zones which each include a plurality of adjacent tracks, and includes sector information showing data assignment for sectors on the optical disc, the optical disc recording apparatus including: a reading unit for reading the sector information from the optical disc; a recording unit for recording the video object onto the optical disc; and a control unit for controlling the reading unit and the recording unit, where the control unit: detects at least one series of consecutive unassigned sectors on the optical disc by referring to the read sector information, each series having a total size greater than a minimum size and being located within a single zone, the minimum size corresponding to a data amount that ensures uninterrupted reproduction of the video object; and controls the recording unit to record the video object into the detected series.
With the above construction, the video object is recorded in a series of consecutive unassigned sectors with the total size greater than a predetermined size, the series without including a zone boundary. This is achieved by searching of such a series of consecutive unassigned sectors prior to the recording of the video object onto the optical disc. The predetermined size is set so that the uninterrupted reproduction is ensured in any types of reproduction apparatuses. As a result, the video object recorded by the present optical disc recording apparatus is reproduced by any types of reproduction apparatuses without gaps in the reproduced video and audio images (without missing frames). Also, the record area is divided into a plurality of zone areas to realize rotation control called Z-CLV (Zone-Constant Linear Velocity) during recording and reproduction. By doing so, a qualified recording efficience is achieved without sacrificing the recording density of the outermost periphery of the optical disc. Also, the uninterrupted reproduction is ensured since the video object does not outstep the zone boundary.
In the above optical disc recording apparatus, the recording area of the optical disc may be divided into a plurality of 2 KB sectors, with each set of 16 consecutive sectors forming one ECC block, the video object is composed of a plurality of packs, each pack having a size of 2 KB, the minimum size is the number of ECC blocks which is represented as “N_ecc” in the following formula: N_ecc=Vo*Tj/((16*8*2048)*(1−Vo/Vr)), where “Tj” represents a maximum jump time of an optical pickup of a reproduction apparatus, “Vr” represents an input transfer rate (Mbps) of a track buffer of the reproduction apparatus, and “Vo” represents an effective output transfer rate (Mbps) of the track buffer.
With the above construction, the predetermined size for ensuring the uninterrupted reproduction can be obtained in case defective sectors are not included in the series of consecutive unassigned sectors.
In the above optical disc recording apparatus, the recording area of the optical disc is divided into a plurality of 2 KB sectors, with each set of 16 consecutive sectors forming one ECC block, the video object is composed of a plurality of packs, each pack having a size of 2 KB, the minimum size is the number of ECC blocks which is represented as “N_ecc” in the following formula: N_ecc=dN_ecc+Vo*Tj/((16*8*2048)*(1−Vo/Vr)), where dN_ecc is a number of ECC blocks, in a series of consecutive unassigned sectors, that include defective sectors, “Tj” represents a maximum jump time of an optical pickup of an reproduction apparatus, “Vr” represents an input transfer rate (Mbps) of a track buffer of the reproduction apparatus, and “Vo” represents an effective output transfer rate (Mbps) of the track buffer.
With the above construction, the predetermined size for ensuring the uninterrupted reproduction can be obtained in case defective sectors are included in the series of consecutive unassigned sectors.
In the above optical disc recording apparatus, the effective transfer rate Vo may be found according to the following formula:
Vo=(N_pack*2048*8)*(27 M/(SCR_first_next−SCR_first_current)
where N_pack is the total number of packs included in the video object that should be recorded in N_ecc ECC blocks, SCR_first_current is a time (i
Gotoh Yoshiho
Kato Hiroshi
Murase Kaoru
Nakatani Tokuo
Okada Tomoyuki
Boccio Vincent F.
Wenderoth , Lind & Ponack, L.L.P.
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