Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
2000-03-24
2004-09-28
Nguyen, Huy (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06798972
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reproducing apparatus and an image reproducing method for improving the controllability of an AV (Audio Visual) server or the like for recording/reproducing image data in reproducing image data.
2. Description of the Related Art
The demand for reproducing a plurality of image and audio data simultaneously from one recording/reproducing apparatus, differing from a conventional VTR (Video Tape Recorder), is growing with the late progress of multi-channelization in providing information due to the dissemination of CATV. (Cable Television) and the like. Then, in order to meet with this demand, an apparatus called an AV server (or a video server) for recording/reproducing image and audio data by using randomly accessible recording media such as a hard disk is now spreading.
For instance, an AV server installed in a broadcasting station is required to have a high data transfer rate in order to keep image and sound quality at certain level or more. It is also required to be able to record a large amount of data in order to broadcast for a long period of time and to have high reliability so as not to interrupt the broadcasting.
Then, the AV server is arranged so as to be able to increase the data transfer rate and the storage capacity by using a recording/reproducing apparatus containing a plurality of HDDs (Hard Disk Drives) which can be operated in parallel and to be able to assure the reliability, even if either one HDD happens to malfunctions, by restoring data by recording parity data.
By the way, an AV server called a multi-channel AV server which can accommodate to various use modes has come to be realized lately to be used in sending a plurality of recorded material data simultaneously through multi-channels or in constructing an NVOD (Near Video On Demand) system for reproducing the same material data through multi-channels by shifting reproducing time.
Technology of RAID (Redundant Arrays of Inexpensive Disks) which was advocated in a paper presented by Patterson et. al., in 1988 (Patterson, D. A., Gibson, G., Kats, R. H., “A Case for Redundant Arrays of Inexpensive Disk (RAID)” ACM SIGMOD Conference, Chicago, III., Jun. 1-3, 1988) is used in the recording/reproducing apparatus used in such multi-channel AV server. While RAID is categorized into five RAID-1 through RAID-5 in the paper, the typical ones are RAID-1, RAID-3 and RAID-5. It is noted although there is a category of RAID-0 as a category in terms of the explanation, it is a mode for operating a plurality of hard disks in parallel.
The RAID-1 is a mode of writing the same contents in two hard disks and the RAID-3 is a mode of recording input data in a plurality of HDDs by dividing it into data of certain length and of generating and writing parity data into another one HDD. The RAID-5 is a mode of recording one divisional data in one HDD as data block by dividing the data into large unit (block), of recording the result of an exclusive logical sum of the data blocks in each HDD corresponding to each other into another HDD as parity block (parity data) and of distributing the parity block to the whole HDDs.
FIG. 1
shows one exemplary structure of the conventional AV server system (the system means one in which a plurality of units are collected logically and it does not matter whether the respective units are stored in one case or not) using the RAID technology.
This AV server system comprises a multi-channel AV server
100
which is capable of providing multi-input/output of a plurality of image data (audio data will be included in image data as necessary hereinafter) and may be utilized as a system for broadcasting CMs (commercial) and news.
The multi-channel AV server
100
comprises a plurality of disk array units
1101
through
1104
for recording input image data and a processor
120
. It is noted that the processor
120
is configured so as to control the input of the image data to be recorded in the disk array units
1101
through
1104
and to control the output of the image data reproduced from the disk array units
1101
through
1104
.
Then, the multi-channel AV server
100
records respective ones of a plurality of input image data DI
1
through IN (N is an integer value greater than 2) inputted from a VTR
121
for reproducing images and a parabola antenna
122
for receiving data via a satellite line at least in one of the disk array units
1101
through
1104
. The multi-channel AV server
100
also reproduces data recorded in the disk array units
1101
through
1104
as necessary and outputs as output data Do
1
through NoN to the monitor
123
and the parabola antenna
124
for example.
FIG. 2
shows one exemplary structure of the disk array unit
110
i
(here, i=1, 2, 3 and 4) in FIG.
1
.
The disk array unit
110
i
comprises a plurality of, e.g., five, HDDs
1311
through
1315
and a disk array controller
130
for controlling those
13115
. In the disk array unit
110
i
, data is read/written from/to the HDDs
1311
through
1315
per predetermined unit (in unit of one frame or one GOP (Group of Picture) for example). While the mode for writing/reading data to/from the plurality of HDDs is the mode called RAID-0, one out of the plurality of HDDs is used for recording the parity data and the remaining HDDs are used for recording the image data in the RAID-3 for example.
It is noted that although the five HDDs
1311
through
1315
are shown in
FIG. 2
, the number of HDDs composing the disk array unit
110
i
is not limited to that number.
Data of one frame is divided in unit of one byte for example in the
130
in the disk array unit
110
i
and the divided data is written to the HDDs
1311
through
1315
in parallel. The
110
i
also reproduces data recorded in the HDDs
1311
through
1315
and outputs the reproduced respective data by multiplexing into the same condition with that at the time of input.
Here, first frame data F
1
and second frame data F
2
are written to the HDDs
1311
through
1315
in parallel in FIG.
2
.
It is noted that in order to reduce the influence of seek (retrieving operation) time of data in the HDDs.
1311
through
1315
, image data is written/read in a certain degree of lump, e.g., several tens frames) at one time of access.
By the way, it is required to reproduce the recorded data at variable speed in structuring an editing system for example by using the multi-channel AV server
100
as described above. That is, the variable speed reproduction is often used in editing works and the like because it is convenient in finding a specific scene for example.
As a method for implementing the variable-speed reproduction in the multi-channel AV server
100
, there has been one of reading image data by culling frames in correspondence to it reproducing speed. However, setting aside the case of the RAID-5 in which image data of one frame is recorded in one HDD in reading image data by culling the frames, there has been a case in which image data necessary for variable-speed reproduction of desired speed cannot be read in the RAID-0 and RAID-3 in which image data of one frame is recorded across the plurality of HDDS.
That is, because image data has been recorded into the plurality of HDDs without controlling the recording pattern specifically in the past, the image data of one frame is distributed into the plurality of HDDs and is-recorded in parallel in the order of line scan (in the order of coding in case when image data is coded) in RAID-0 and RAID-3. Accordingly, although the continuous frames may be reproduced by seeking image data of the first frame and then by reading the image data continuously in each HDD, image data of certain frame must be sought every time when the image data of frame to be read changes in each HDD in reproducing sporadic frames. Because it takes about 10 to 20 mil-seconds in seeking data in the HDD, the performance would be about 3 frames/100 msec for example as data reading speed when data must be sought every time when image data of
Hirose Masaki
Ito Norikazu
Katsuo Satoshi
Nakamura Shouji
Shiga Tomohisa
Frommer William S.
Frommer & Lawrence & Haug LLP
Lee Samuel S.
Nguyen Huy
Sony Corporation
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