Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1999-06-08
2003-03-25
Tran, Thai (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000, C386S349000, C386S349000
Reexamination Certificate
active
06539164
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a disk media, such as a video disk or optical disk for recording a digital image signal, such as an image signal having been coded, e.g., converted to high-efficiency coded data, and a method of and device for recording and playing back a digital image signal on or from such a disk media, a high-efficiency-coded data on a video disk, and method and device for playing back the image by restoring the high-efficiency-coded data from the video disk.
The present invention also relates to a method of performing fast playback or retrieval from a disk media.
FIG. 40
shows a conventional optical disk recording/playback device described in Japanese Patent Kokai Publication No. 114369/1992. As illustrated, it comprises an A/D converter
12
for converting a video signal, audio signal, or the like into digital information, an information compressing means
13
, a frame-sector conversion means
14
for converting compressed information into sector information whose length is equal to an integer multiple of a frame, an encoder
15
, and a modulator
16
for conversion into modulated codes so as to reduce inter-code interference on a recording media. A laser drive circuit
17
and a laser output switch
18
serve to modulate a laser beam according to the modulated codes.
An optical head
19
is for emitting the laser light. An actuator
20
is for tracking the light beam emitted from the optical head
19
. A traverse motor
21
is for moving the optical head
19
. A disk motor
22
is for rotating a disk
23
. Reference numeral
24
denotes a motor drive circuit,
25
denotes a first control circuit, and
26
denotes a second control circuit. A playback amplifier
27
is for amplifying a playback signal sent from the optical head
19
. A demodulator
28
is for acquiring data from a modulated signal that has been recorded. Reference numeral
29
denotes a decoder, and
30
denotes a frame-sector inverse conversion circuit. An information expanding means
31
is for expanding compressed information. A D/A converter
51
is for converting expanded information into, for example, an analog video signal or audio signal.
FIG. 41
is a simplified illustration of a data structure (layered structure) according to the moving picture experts group (hereinafter MPEG) system that is becoming the standard for transmission and storage of digital moving picture information in compressed form.
In
FIG. 41
, reference numeral
51
denotes a sequence formed of a plurality of image information blocks, also called GOPs (groups of pictures)
52
and sequence headers. Each GOP
52
is formed of a plurality of pictures (screens) or image data for a plurality of frames
53
. Each picture (screen) is divided into slices
54
, and each of the slices
54
is formed of a plurality of macroblocks
55
. Each macroblock
55
is formed of four adjoining blocks
56
y
of luminance signal (Y), one block
56
b
of a color difference signal (Cr), and one block
56
r
of another color difference signal (Cb). The positions of the blocks
56
b
and
56
r
of the color difference signals are associated with the positions of the four blocks
56
y
of the luminance signal.
One block
56
y
of luminance signal is formed of eight pixels by eight pixels, and forms a minimum coding unit.
The block
56
y,
56
b,
56
r
is regarded as a unit for information compression based on discrete cosine transform (hereinafter DCT). The macroblock
55
is a minimum unit for motion-compensated prediction. Detection of a motion vector used for the motion-compensated prediction is carried out taking in macroblock units, with regard to each macroblock.
The coded data is output as a bit stream (continuous serial data) having a structure described above.
The sequence
51
has a structure shown in FIG.
42
. In the figure,
65
a,
65
b,
65
c
and
65
d
denote GOPs, and
66
a,
66
b
and
66
d
denote sequence headers (SHs). The sequence headers are provided to designate the image format such as the number of pixels, the number of lines of the image, and may be appended to the head of all or only some of the GOPs. In the figure, GOP
1
, GOP
2
and GOP
4
are provided with a sequence header appended to the head thereof, while GOP
3
is not provided with a sequence header. Provided at the start of the GOP is data (hereinafter referred to as “time code”) indicating the time from the start of the sequence (title, program).
FIG. 43
shows a coding scheme for a case where one GOP
52
is composed of ten pictures (screens, frames). In
FIG. 43
, reference numeral
67
denotes an I picture that is image information subjected to information compression based on intra-frame DCT.
68
denotes a P picture that is image information subjected to the information compression based on intra-frame DCT as well as to motion compensation using the temporally preceding I picture
67
as a reference screen.
69
denotes a B picture subjected to the information compression based on intra-frame DCT and to motion compensation using the temporally preceding and succeeding I and/or another P pictures
67
,
68
as reference screens.
Next, the operations of the conventional optical disk recording/playback device will be described. With the advancement of compression of digital image information technology, it has become possible to realize an image filing system in which compressed moving picture information is recorded on optical disks, offering more excellent retrievability than tape media represented by a conventional VTR, and which is easy to use. Since this kind of disk filing system handles digital information, degradations due to copying are not observed. Moreover, since optical recording/playback is employed, a non-contacting and therefore reliable system can be constructed.
Conventionally, recording of compressed moving picture information on an optical disk is achieved by recording digital compressed moving picture information, which conforms to the MPEG system shown in
FIG. 41
, in an optical disk device shown in the block diagram of FIG.
40
. Image information digitized by the A/D converter
12
is transformed by the information compressing means
13
according to the MPEG or any other standard compressed moving picture system. The compressed information is encoded by the encoder
15
, and modulated by the modulator
16
in order to reduce the influence of inter-code interference on the optical disk
23
. The resultant information is recorded on the optical disk
23
. At this time, data is allocated such that, for example, the amount of data per GOP is substantially identical (in other words, at a fixed rate), and data is allocated to sectors whose length is equal to an integer multiple of a frame. This facilitates GOP-by-GOP editing or the like.
For playback, image information read from the optical disk
23
is amplified by the playback amplifier
27
. Digital data is then restored by the demodulator
28
and decoder
29
. Thereafter, pure and original image data devoid of address and parity bits is restored by the frame-sector inverse conversion means. The information expanding means
31
performs MPEG decoding so as to restore the original digital video signal. The D/A converter
32
provides an analog video signal that can be displayed on a monitor or the like.
Assuming that the aforesaid MPEG system is used for digital moving picture compression, a coding scheme such as the one shown in
FIG. 43
is recorded on the optical disk
23
as it is. Herein, the coding scheme is constructed by combining the I picture
67
, which has been subjected to information compression based on intra-frame DCT, with several P pictures
68
which have been subjected to information compression by intra-frame DCT and motion compensation using the temporally preceding I picture
67
or another P picture
68
as a reference screen, and several B pictures
69
which have been subjected to information compression, by intra-frame DCT and motion compensation using the I and/or P pictures
67
,
68
as reference screens.
The P and B
Asamura Yoshinori
Kasezawa Tadashi
Kiyose Yoshihiro
Mishima Hidetoshi
Nagasawa Masato
Mitsubishi Denki & Kabushiki Kaisha
Tran Thai
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