Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1998-03-19
2001-05-29
Garber, Wendy R. (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06240244
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a disk apparatus for recording and reproducing digital continuous data such as video data or audio data, and more particularly, to a video disk apparatus for alternately recording and reproducing data by time sharing.
Developments have been made to a video disk apparatus for recording and reproducing a digital video image into and from a storage medium, such as an optical disk or the like, using video compression, such as a Moving Picture Experts Group (MPEG) method.
According to a video disk apparatus using a conventional optical disk, digital video data compressed by MPEG encoder as a digital video compressor or digital video data supplied by broadcasting or CATV (cable television) is once stored into a buffer memory in which an adjustment is made on a difference between the bit rate (which means the bit capacity transferred per second) of the digital video data inputted and the recording/reproducing speed (which means the bit capacity recorded/reproduced per second) of an optical disk. Normally, the bit rate of inputted digital video data is slower than the recording/reproducing speed of an optical disk.
As for a practical form of using such a video disk apparatus, it will be very advantageous for practical use if a video image once recorded can be reproduced during recording. For example, a user who comes back home while a program is being recorded by a recorder that had been set by a timer may wish to watch the program from the beginning while the program is still being recorded.
However, in a conventional video disk apparatus, a video image can be reproduced only after the recording of the image is completed. Thus, it is not possible to simultaneously reproduce a video image while recording the video image. In order to solve this problem, a conventional apparatus comprises independent optical heads for recording and reproducing, respectively, thereby to realize a simultaneous recording/reproducing function. This method, however, results in an increase in costs since a plurality of optical heads are used.
BRIEF SUMMARY OF THE INVENTION
The present invention has an object of providing a video disk apparatus capable of reproducing a portion of digital continuous data which has already been recorded during recording of digital continuous data such as video data, audio data, or the like, using a single recording/reproducing head.
According to the present invention, there is provided a disk apparatus comprising a continuous data input/output section for inputting and outputting digital continuous data at a first bit rate, a recording/reproducing section for recording and reproducing the continuous data in and from a disk-like recording medium, a buffer memory for temporarily buffering input digital continuous data and for temporarily buffering time-based digital data reproduced from the recording medium, and a control section for controlling recording of time-based digital data onto a predetermined recording area on the recording medium and reproducing of digital continuous data from a predetermined reproducing area on the recording medium so as to be performed alternately in a time-sharing manner.
The control section executes the following control:
(a) Writing in a recording buffer memory digital data inputted during recording onto a recording area, during reproducing into a reproducing area, and during an access time period for which a recording/reproducing head is moved between a recording and a reproducing area for accessing.
(b) Reading and recording digital data buffered in the recording buffer memory, at a recording speed which is twice or more greater than an average bit rate of digital data inputted, into a recording area, during recording onto the recording area.
(c) Reproducing and writing digital continuous data recorded in a reproducing area, at a recording speed which is twice or more greater than the average bit rate, into a reproducing buffer memory, during reproducing from the reproducing area.
(d) Reading and outputting digital data buffered in the reproducing buffer memory during recording onto a recording area, during reproducing into a reproducing area, and during an access time period for which the recording/reproducing head is moved between a recording and a reproducing area for access, to a continuous data output device.
The recording speed is set to (T1+T2+2S)A/T1 bps or higher, the reproducing speed is set to (T1+T2+2S)A/T2 bps or higher, and the total sum of the memory capacities of the recording buffer memory and the reproducing buffer memory is set to (4S+T1+T2)A bits or more, where an average recording time period is T1 seconds for every time of recording, an average reproducing time period is T2 seconds for every time of reproducing, a maximum access time period of the recording medium (determined by adding a time period required for rotating the recording medium by one rotation, to a seek time period for moving the recording/reproducing head from the innermost circumference of the recording medium to the outermost circumference thereof) is S seconds, and the average bit rate of digital data inputted is A (bps), when recording onto a recording area and reproducing from a reproducing area are alternately performed.
Further, a display screen of a display device as the continuous data output device is divided into two areas for simultaneously displaying a digital video image of digital continuous data being recorded onto a recording area and a digital video image reproduced from a reproducing area.
The disk apparatus of the present invention reproduces digital continuous data which has already been recorded, during recording digital continuous data.
The present invention may have an average bit rate of digital continuous data A (bps) and the maximum access time period of a disk-like recording medium (determined by adding a time period for rotating the recording medium by one rotation, to a seek time period for moving the recording/reproducing head from the innermost circumference of the recording medium to the outermost circumference thereof) is S seconds.
To simultaneously carry out recording of digital video data and reproducing of digital continuous data which has already been recorded on the recording medium using one single recording/reproducing head, recording and reproducing with respect to the recording medium is performed in a time sharing manner, at a speed which is not lower than the average bit rate of two pieces of digital continuous, one being recorded and the other being reproduced. Specifically, recording of digital continuous data onto the recording medium is performed in a certain time period, while reproducing of digital continuous data from the recording medium is performed in another certain time period. Therefore, the recording/reproducing speed of the recording medium is at least 2A (bps) or higher, in order to process digital video data at an average bit rate A (bps).
Further, since one recording/reproducing head is used and the positions of recording and reproducing areas are not always equal to each other, switching between recording and reproducing takes an access time period for moving the head between both of the areas. For example, when a time sharing procedure includes “recording for T1 seconds”, “accessing for S seconds from a recording area to a reproducing area”, “reproducing for T2 seconds”, and “accessing for S seconds from a reproducing area to a recording area” is repeated to perform recording and reproducing, two accesses are made between areas in one cycle of the time sharing procedure.
Accordingly, during recording, inputted digital continuous data of an amount equivalent to (T1+T2+2S) seconds is recorded in T1 seconds, so that the recording speed of the recording medium is (T1+T2+2S)A/T1 bps or higher. Likewise, the reproducing speed is (T1+T2+2S)A/T1 bps or higher. Where T1=T2 is satisfied, the recording/reproducing speed of the recording medium is (2+2S/T1)A (bps) or higher.
Boccio Vincent F.
Garber Wendy R.
Kabushiki Kaisha Toshiba
Pillsbury & Winthrop LLP
LandOfFree
Disk apparatus having a single recording head and capable of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Disk apparatus having a single recording head and capable of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disk apparatus having a single recording head and capable of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2457652