Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1999-04-29
2004-04-27
Boccio, Vincent (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C386S349000, C386S349000, C360S027000, C348S552000
Reexamination Certificate
active
06728470
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data recording and reproducing apparatus and method for recording and reproducing video data and the like.
2. Description of the Related Art
In recent years, in association with the increase in the number of channels of providing information because of the widespread of CATVs (community antenna television or cable televisions) and the like, different from a VCR (Video Cassette Recorder) of a related art, the demand of simultaneously reproducing plural video and audio data from a single video and audio data recording and reproducing apparatus is increasing. In order to satisfy the demand, an apparatus called an audio video (hereinbelow, also referred to as “AV”) server for recording and reproducing video and audio data by using recording and reproducing media which are randomly accessible such as hard disks is being spread.
Generally, for example, in an AV server in a broadcasting station, a data transfer rate required is high due to a demand of the image quality and sound quality and the capacity has to be large to record data of long hours. Therefore, an attempt to realize higher data transfer rate and larger capacity by using a data recording and reproducing apparatus including a plurality of hard disk drives (hereinbelow, referred to as HDDs) which store video and audio data and can be operated in parallel and an attempt to assure the reliability by recording parity data even if any of the HDDs gets out of order are made. Consequently, even when the number of channels required differs according to the contents of programs which broadcasting stations are providing and broadcasting modes, a multi-channel AV server which can accommodate various usage patterns such as a pattern of recording plural material data in a distributed manner and simultaneously transmitting the data to multichannels and a pattern of constructing a near video on demand (NVOD) system by reproducing the same material data by deviating reproduction time through multichannels can be realized.
In the data recording and reproducing apparatus which is used for such a multichannel AV server, the RAID (Redundant Arrays of Inexpensive Disks) technique proposed in “A Case for Redundant Arrays of Inexpensive Disks (RAID)”, ACM SIGMOD Conference, Chicago, Ill., Jun. 1 to 3, 1988 by Patterson, D. A., Gibson, G., and Kats, R. H is employed. In the paper, RAID is classified into five classes of RAID-1 to RAID-5. Among them, representative ones are RAID-1, RAID-3, and RAID-5. As a classification for explanation, there is RAID-0 as well. RAID-0 relates to a method of operating a plurality of hard disks in parallel.
RAID-1 relates to a method of writing the same contents into two hard disks. RAID-3 relates to a method of dividing input data in predetermined length, recording divided data into a plurality of HDDs, generating parity data, and writing the parity data into another HDD. Meanwhile, RAID-5 relates to a method of setting a larger data dividing unit (block), recording one divided data as a data block into one HDD, recording the result (parity data) of the exclusive OR of data blocks corresponding each other in the HDDs as a parity block to another HDD, and distributing the parity block to all of the HDDs.
FIG. 1
is a construction diagram showing an example of the construction of an AV server using the RAID technique. An AV server
100
is used as a CM (commercials) transmitting apparatus, a news editing apparatus, or the like for providing multiple inputs and outputs of plural image data. The AV server
100
comprises a plurality of disk array apparatuses
110
1
to
110
4
for recording input image data and a processor
120
for inputting image data to be recorded on each of the disk array apparatuses
110
1
to
110
4
and outputting the image data reproduced from each of the disk array apparatuses
110
1
to
110
4
.
In the AV server
100
, for example, each of plural input image data D
Il
to D
In
(n is an integer value of 2 or larger) inputted from a video device
121
or a transmitter-receiver
122
for satellite channels is recorded into at least one of the disk array apparatuses
110
1
to
110
4
. As required, the data recorded in the disk array apparatuses
110
1
to
110
4
is reproduced and outputted as output data D
01
to D
0n
to, for example, a video monitor
123
or a transmitter-receiver
124
for satellite channels.
FIG. 2
is an explanatory diagram showing an example of the structure of a disk array apparatus
110
(shown as a representative of
110
1
to
110
4
). The disk array apparatus
110
comprises a plurality of HDDs
131
1
to
131
5
and a disk array controller
130
for controlling the HDDs
131
1
to
131
5
. In the disk array apparatus
110
, data in a predetermined unit (for example, a frame or GOP (Group Of Picture) unit) is written/read in parallel to/from the HDDs
131
1
to
131
5
. The structure in which data is simply read and written in parallel is according to the method of RAID-0. In case of the method of RAID-3, one of the plurality of the HDDs
131
1
to
131
5
is dedicated to parity data. Although five HDDs
131
1
to
131
5
are shown in
FIG. 2
, the number of HDDs is not limited to five.
In the disk array apparatus
110
, the inputted image data D
I
of, for example, one frame is divided, for instance, on a byte unit basis by the disk array controller
130
and the divided data is sequentially written in parallel onto hard disks in the HDDs
131
1
to
131
5
by the HDDs
131
1
to
131
5
.
FIG. 2
illustrates a case where data F
1
in the first frame and data F
2
of the second frame are written in parallel onto the hard disks in the HDDs
131
1
to
131
5
. In the disk array apparatus
110
, when data recorded in the HDDs
131
1
to
131
5
is reproduced, the data is reproduced from the HDDs
131
1
to
131
5
by the disk array controller
130
. The reproduced data is arranged in the same order as the order upon input, formed as a collection of data, and outputted as reproduction data D
0
.
In the disk array apparatus
110
, in order to reduce the influence of seek (seeking operation) time of data in the HDDs
131
1
to
131
5
, a certain amount (for example, few tens of frames) of data has to be accessed (read/written) in a lump per time.
Meanwhile, in the data recording and reproducing apparatus represented by the AV server
100
, there is a case that variable speed reproduction of recorded data is desired to be performed. In this case, the data recording and reproduced apparatus of the related art has problems such that information necessary for the variable speed reproduction at a desired speed cannot be obtained and an information dropout occurs in a reproduction image due to the variable speed reproduction for the following reasons.
For example, in the data recording and reproducing apparatuses according to the RAID-0 and RAID-3 methods, data is written/read in parallel to/from HDDs on a unit image basis. In case of performing the variable speed reproduction, it takes time to seek image data to be reproduced next (for example, about 10 to 20 msec) every unit image. As the data reading speed, for example, the performance of about 3 frames/100 msec is the limit. In the AV server
100
which is basically multi-accessible, therefore, data can be outputted only with the performance of about few frames/second. There is consequently a problem such that information of 30 frames/second which is normally necessary cannot be acquired.
For example, in a data recording and reproducing apparatus employing RAID-5, since each unit image is recorded in individual HDD, different from the RAID-0 and RAID-3 methods, a problem caused by the seek operation does not occur. For example, however, in case of reproducing continuous frame data of frames F
1
, F
2
, F
3
, . . . at double speed, skipped data of frames F
1
, F
3
, F
5
, F
7
, F
9
, . . . is outputted, so that there is a problem such that information of data of frames F
2
, F
4
, F
6
, F
8
, . . . is not outputted. For example, in
Fujita Hiroyuki
Hirose Masaki
Ito Norikazu
Katsuo Satoshi
Sato Koichi
Boccio Vincent
Fletcher James A
Frommer William S.
Frommer & Lawrence & Haug LLP
Kessler Gordon
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