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Claims  |
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We claim:
1. A picture data recording/reproducing system including a recording
apparatus and a reproducing apparatus, said recording apparatus
comprising:
input means for receiving digital picture data;
coding means for inter-frame coding the digital picture data supplied from
said input means to produce coded picture data, said coding means
including a first frame memory for storing digital picture data of a
previous frame;
first clear means for substantially clearing the content of said first
frame memory for every predetermined number of frames and for outputting
cleared frame number data identifying the cleared frames;
multiplexing means for multiplexing the coded picture data supplied from
said coding means with frame number data corresponding to said coded
picture data supplied from said first clear means to produce multiplexed
data; and
recording means for recording the multiplexed data supplied from said
multiplexing means on a recording medium; and
said reproducing apparatus comprising:
means for reading out the recorded multiplexed data from said recording
medium;
first decoding means for decoding said inter-frame coded picture data
contained in the multiplexed data, said first decoding means including a
second frame memory for storing decoded picture data of a previous frame;
second clear means for substantially clearing the content of said second
frame memory for every frame designated by said frame number data;
second decoding means for decoding only the coded picture data contained in
the multiplexed data for the frames designated by said frame number data;
selecting means for selecting one of two channels of data resulting from
decoding of coded picture data by said first decoding means and second
decoding means, respectively; and
output means for outputting decoded picture data selected by said selecting
means.
2. A picture data recording/reproducing system including a recording
apparatus and a reproducing apparatus, said recording apparatus
comprising:
input means for receiving digital picture data of plural frames;
coding means for coding the digital picture data received from said input
means for all frames in accordance with an inter-frame coding scheme into
coded picture data by making use of a previous frame of digital picture
data, said coding means including a coder frame memory for storing digital
picture data for said previous frame;
coder memory clear means for substantially clearing said coder frame memory
in said coding means for every predetermined number of frames of picture
data to cause said coding means to operate in an intra-frame coding scheme
for coding those frames which are coded while the coder frame memory is
cleared;
recording means for recording said coded picture data received from said
coding means on a recording medium;
said reproducing apparatus comprising:
decoder selection control means for specifying one of two operations
according to a selected picture producing mode;
reading-out means for reading out either said all coded picture data in a
first operation or only intra-frame coded picture data contained in said
coded picture data received from said recording medium for every
predetermined number of frames in a second operation under control of said
decoder selection control means;
decoding means for decoding said coded picture data received from said
reading-out means in accordance with an inter-frame decoding scheme to
produce reproduced picture data by making use of a previous frame of said
reproduced picture data, said decoding means including a decoder frame
memory for storing said reproduced picture data for said previous frame;
decoder memory clear means for substantially clearing said decoder frame
memory in said decoding means while intra-frame coded picture data is
decoded to cause said decoding means to operate in an intra-frame decoding
scheme; and
output means for outputting reproduced picture data received from said
decoding means.
3. A picture data recording/reproducing system according to claim 2,
wherein said recording apparatus further comprises frame number adding
means for generating frame number data for every frame of the digital
picture data and for adding the frame number data to every frame of said
coded picture data, and said coder memory clear means includes means for
operating on frames of the digital picture data to be intra-frame coded in
said coding means for said every predetermined number of frames on the
basis of the frame number data generated by said frame number adding
means.
4. A picture data recording/reproducing system according to claim 3,
wherein said reproducing apparatus further comprises frame number
extracting means for extracting said frame number data from every frame of
the read-out coded picture data, and wherein said reading-out means reads
out the intra-frame coded picture data contained in the coded picture data
during a second of said two operations of said decoder selection control
means in accordance with the frame number data extracted by said frame
number extracting means.
5. A picture data recording/reproducing system including a recording
apparatus and a reproducing apparatus, said recording apparatus
comprising:
input means for receiving digital picture data of plural frames in
sequence;
coding means for coding the digital picture data for all frames to produce
coded picture data in accordance with an interleave inter-frame coding
scheme which codes each current frame of digital picture data using an
inter-frame coding scheme together with a frame of digital picture data
appearing earlier in said sequence by a predetermined frame series number
of at least two frames where each frame of digital picture data belongs to
a respective one of a plurality of picture frame series, each picture
frame series including plural frames of digital picture data separated by
said predetermined number of frames; and
recording means for recording said coded picture data received from said
coding means on a recording medium:
said reproducing apparatus comprising:
decoder selection control means for specifying one of two operations
according to a selected picture producing mode;
reading-out means for reading out either all frames of coded picture data
in a first operation or only periodic frames of said coded picture data
which are separated by said predetermined frame series number of frames
from said recording medium under control of said decoder selection control
means in a second operation;
decoding means for producing reproduced picture data by decoding interleave
inter-frame coded picture dam for each frame of coded picture data
received from said reading-out means on a picture frame series basis in
accordance with an interleave inter-frame decoding scheme by making use of
a previous frame of the reproduced picture data in the same picture frame
series as that to which the frame to be decoded belongs: and
output means for outputting reproduced picture data received from said
decoding means;
wherein said coding means includes coder frame memories in a number equal
to that of said predetermined frame series number of frames, each coder
frame memory storing digital picture data of a previous frame of each
picture frame series, and coder memory switching means for selecting
sequentially one of said coder frame memories corresponding to a picture
frame series of digital picture data to be coded for every number of
frames, in order to realize the interleave inter-frame coding of the
digital picture data for each frame by changing over said coder frame
memories using said coder memory switching means; and
said decoding means includes decoder frame memories in a number equal to
that of said predetermined frame series number of frames, each decoder
frame memory storing said reproduced picture data of a previous frame of
picture data in each picture frame series, and decoder memory switching
means for selecting one of said decoder frame memories according to the
picture frame series of each frame of the reproduced picture data, in
order to realize interleave inter-frame decoding for each frame of the
coded picture data by changing over said decoder frame memories using said
decoder memory switching means.
6. A picture data recording/reproducing system according to claim 5,
wherein said recording apparatus further comprises frame number adding
means for generating frame number data for every frame of the digital
picture data and for adding the frame number data to every frame of the
coded picture data, and said coder memory switching means including means
for sequentially selecting one of said coder frame memories in synchronism
with the frame of digital picture data to be coded for every said
predetermined frame series number of frames of digital picture data in
accordance with the frame number data generated by said frame number
adding means; and
said reproducing apparatus further comprises frame number extracting means
for extracting frame number data from every frame of read-out data, said
decoder memory switching means including means for selecting one of said
decoder frame memories according to the picture frame series of each frame
of the reproduced picture data by the frame number data extracted by said
frame number extracting means, and said decoder selection control means
including means for selecting the frames to be read out by said
reading-out means according to the frame number data extracted by said
frame number extracting means and said selected picture reproducing mode.
7. A picture data recording/reproducing system including a recording
apparatus and a reproducing apparatus, said recording apparatus
comprising:
input means for receiving digital picture data;
coding means for inter-frame coding the digital picture data supplied from
said input means to produce coded picture data, said coding means
including a first frame memory for storing digital picture data of a
previous frame;
first clear means for substantially clearing the content of said first
frame memory for every predetermined number of frames and for outputting
cleared frame number data identifying the cleared frames;
multiplexing means for multiplexing the coded picture data supplied from
said coding means with said frame number data corresponding to said coded
picture data supplied from said first clear means to produce multiplexed
data; and
recording means for recording the multiplexed data supplied from said
multiplexing means on a recording medium; and
said reproducing apparatus comprising:
means for reading out the recorded multiplexed data from said recording
medium;
decoding means for decoding said inter-frame coded picture data contained
in the multiplexed data, said decoding means including a second frame
memory for storing decoded picture data of a previous frame;
second clear means for substantially clearing the content of said second
frame memory for every frame designated by said frame number data;
output means for outputting decoded picture data decoded by said decoding
means.
8. A picture data recording/reproducing system according to claim 2,
wherein said recording apparatus further comprises additional data adding
means for generating additional data indicative of a coding scheme for
every frame of the digital picture data and for adding said additional
data to every frame of said coded picture data, and said coder memory
clear means includes means for operating on frames of the digital picture
data to be intra-frame coded in said coding means for said every
predetermined number of frames on the basis of said additional data
generated by said additional data adding means.
9. A picture data recording/reproducing system according to claim 8,
wherein said reproducing apparatus further comprises additional data
extracting means for extracting said additional data from every frame of
the read-out coded picture data, and wherein said reading-out means reads
out the intra-frame coded picture data contained in the coded picture data
during a second of said two operations of said decoder selection control
means in accordance with the additional data extracted by said additional
data extracting means.
10. A picture data recording/reproducing system according to claim 5,
wherein said recording apparatus further comprises additional data adding
means for generating additional data indicative of a predetermined frame
series number for every frame of the digital picture data and for adding
the additional data to every frame of the coded picture data, and said
coder memory switching means including means for sequentially selecting
one of said coder frame memories in synchronism with the frame of digital
picture data to be coded for every said predetermined frame series number
of frames of digital picture data in accordance with the additional data
generated by said additional data adding means; and
said reproducing apparatus further comprises additional data extracting
means for extracting said additional data from every frame of read-out
data, said decoder memory switching means including means for selecting
one of said decoder frame memories according to the picture frame series
of each frame of the reproduced picture data by said additional data
extracted by said additional data extracting means, and said decoder
selection control means including means for selecting the frames to be
read out by said reading-out means according to said additional data
extracted by said additional data extracting means and said selected
picture reproducing mode. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention relates generally to a picture data
recording/reproducing system. More particularly, the invention is
concerned with a picture data recording/reproducing system which is
capable of recording picture data at a high compression rate and
reproducing the picture data selectively at a normal reproduction speed
and a higher reproduction speed.
As a system for recording and reproducing dynamic picture (image) data
known heretofore, there may be mentioned a system which is disclosed in
JP-A-62-164391 and in which a picture coding transmission apparatus is
employed.
FIGS. 1 and 2 of the accompanying drawings are block diagrams showing a
general arrangement of a moving picture recording/reproducing system based
on the picture data transfer scheme known heretofore. More specifically,
FIG. 1 shows a moving picture recording apparatus designed for recording
on an optical disc digitized moving picture data after compression
thereof, and FIG. 2 shows a moving picture reproducing apparatus for
decoding the picture data read out from the optical disk and expanding the
data on a real time basis for thereby displaying the moving picture. In
FIG. 1, a reference numeral 11 denotes an input terminal for a picture
signal, 12 denotes generally a moving picture coding unit, 13 denotes an
optical disc recording unit, and a numeral 14 denotes an optical disc
storage. The moving picture recording apparatus is constituted by the
moving picture coding unit 12 and the optical disc recording unit 13. On
the other hand, the moving picture coding unit 12 is composed of an
analogue-to-digital (A/D) converter 15, a frame memory 17, a picture
coding circuit 18 and a buffer memory 20.
Referring to FIG. 2, a numeral 21 denotes an optical disk reading unit, 22
generally denotes a moving picture decoding unit, and 23 denotes an output
terminal for the reproduced picture signal. The moving picture reproducing
apparatus is constituted by the optical disc reproducing unit 21 and the
moving picture decoding unit 22, which in turn is composed of a buffer
memory 25, a picture decoding circuit 26, a frame memory 28 and a
digital-to-analogue (D/A) converter 29, wherein a numeral 27 designates
picture data.
In operation, the input picture signal applied to the input terminal 11 is
supplied to the input of the moving picture coding unit 12, wherein the
analogue picture signal is converted into digital picture data by the A/D
converter circuit 15, which data is outputted onto a line 16 and thence
supplied to the frame memory 17 to be stored therein. The picture coding
circuit 18 encodes the picture data outputted from the frame memory 17
with high efficiency to thereby generate coded data which is then stored
in the buffer memory 20 over a line 19. The coded data stored in the
buffer memory 20 is then supplied to the optical disc recording unit 13,
whereby the coded moving picture data transferred from the moving picture
coding unit 12 is recorded on the optical disc 14. Of course, in the case
of a read-only optical disk in which data can not be written by the user,
such as a CD-ROM (Compact Disc--Read Only Memory) and others, a prototype
is first prepared, from which replica discs are manufactured by press
equipment.
Upon reproduction of the optical disc 14 having the coded moving picture
data recorded thereon by the optical disc reading unit 21, the coded data
read out from the optical disc 14 is supplied to the moving picture data
decoding unit 22. More specifically, the coded picture data outputted on
the line 24 is first stored in the buffer memory 25 and subsequently
decoded by the picture data decoding circuit 26, whereby the decoded
picture data is generated. The decoded picture data thus generated is
supplied to the frame memory 28 over a line 27 to be stored and held
therein. Subsequently, the decoded picture data is read out from the frame
memory 28 and undergoes D/A conversion in the D/A converter circuit 29,
the resultant analogue picture signal being then outputted as the output
picture signal through the terminal 23.
With regard to the moving picture data coding scheme, there are known an
intra-frame coding scheme and an inter-frame coding scheme, as is
disclosed, for example, in JP-A-61-24577. According to the intra-frame
coding scheme, the moving picture or picture data is coded completely in
each of the data frames, as typified by a DPCM (Differential Pulse Code
Modulation) according to which the difference between the current data
value and the before or after data value is determined to be coded. On the
other hand, according to the inter-frame coding scheme, the moving picture
data is coded on a frame basis (i.e. frame by frame) by making use of
frame information in the past, as exemplified by a changed-area coding
scheme according to which the coding is performed only for the part of the
data that has undergone a change from that of the preceding frame data. In
general, the inter-frame coding scheme can assure a higher ratio of data
compression than the intra-frame coding system, presenting the advantage
that the amount of the coded data is correspondingly reduced.
FIG. 3 of the accompanying drawings shows in a block diagram an exemplary
structure of the coding circuit 18 implemented on the basis of the DPCM
principle, and FIG. 4 shows in a block diagram a structure of the decoding
circuit 26 which is compatible with the DPCM coding circuit 18. Referring
to FIG. 3 , a reference numeral 30 denotes a data value subtraction
circuit, 31 denotes a quantitizing circuit for quantitizing data with a
decreased number of the quantitizing levels to thereby reduce further the
amount of data to be processed, 32 denotes a representative value setting
circuit, 35 denotes a data value addition circuit, and a numeral 34
denotes a data value hold circuit. The data value substraction circuit 30
serves for determining the difference between the value of the picture
data 16 inputted currently thereto and the immediately preceding value of
the picture data held in the data value hold circuit 34. The difference
data thus derived is then quantitized by the quantitizing circuit 31 with
the number of quantitizing levels being decreased to an appropriate value,
whereby coded data is generated to be outputted onto the line 19. In the
representative value setting circuit 32, the coded data undergoes a
reverse quantitization for restoring the original bit number by adding
"Os" in a number corresponding to the number of bits deleted by the
quantitizing circuit 31 to be subsequently added to the value of the
immediately preceding picture data by the data value addition circuit 33.
In this manner, the picture data is, so to say, locally decoded through
cooperation of the circuits 32 and 33. The picture data resulting from the
local decoding mentioned above is stored and held in the data value hold
circuit 34 to be thereby delayed by one picture element. Now, referring to
FIG. 4, a numeral 35 denotes a representative value setting circuit, 36
denotes a data value addition circuit and 37 denotes a data value hold
circuit. The coded data 24 undergoes a reverse quantitization in the
representative value setting circuit 35 and is subsequently added by the
value addition circuit 36 to the value of the immediately preceding
picture data stored and held in the data value hold circuit 37 to be
thereby decoded. The picture data generated on the line 27 as a result of
the decoding is stored and held in the data value hold circuit 37 to be
delayed by one picture element.
FIG. 5 is a schematic diagram for illustrating conceptually a changed-area
coding scheme exemplifying typically the inter-frame coding scheme. In a
frame generally designated by 38 in this figure, pictures depicted in a
solid line belong to the frame being generated currently, while pictures
depicted in broken lines are those of the immediately preceding frame.
According to the changed-area coding system, only the regions 39 each
indicated as enclosed by a thick solid line need to be coded, which means
that a high ratio of compression can be accomplished. For coding the
picture data within the changed areas or regions, there can be employed,
for example, the DPCM intra-frame coding system. In this case, it is
however noted that the frame memories for holding the picture data of the
immediately preceding frame must be provided in association with the
coding circuit 18 and the decoding circuit 26, respectively, because the
data of the immediately preceding frame has to be made use of upon coding
and decoding, respectively.
Next, referring to FIGS. 6A to 6C, discussion will be made concerning a
recording format for the coded moving picture data and a reproducing
method adopted in the prior art dynamic picture reproducing/recording
apparatus described hereinbefore in conjunction with FIGS. 1 and 2. FIG.
6A illustrates disposition or array of the coded moving picture data
recorded on a track of the optical disk 14, and FIGS. 6B and 6C are views
for illustrating a method of reproducing the coded data. As will be seen
in FIG. 6A, the coded picture data is recorded on a frame basis in the
order of the frame numbers assigned sequentially to a series of frames 58.
The data compression is so realized that the amount of coded data for one
frame becomes smaller than the maximum amount of the data which can be
transferred within a period taken for displaying one frame (1/30 sec.) and
which is determined on the basis of the maximum data transfer rate in the
data reproduction from the optical disc. Upon reproduction of the moving
picture data at an ordinary or normal speed, the coded data is read out on
a frame basis in the order of the frame numbers, as shown in FIG. 6B. On
the other hand, upon reproduction of the moving picture data at a high
speed, e.g. at a trebled speed, the coded data is read out every third
frame, as shown in FIG. 6C. It should further be added that in case the
inter-frame coding scheme is adopted, the high speed reproduction based on
the frame thinning-out or skipping mentioned above can not be realized.
When the intra-frame coding scheme is adopted, the high speed reproduction
is certainly possible, because the picture data can be coded completely
and independently within each frame. However, a difficulty will be
encountered in an attempt to perform a recording for an extended time
because of the impossibility of compressing the picture data at a
relatively high ratio. On the other hand, when the inter-frame coding
scheme is adopted, the picture data can certainly be compressed at a high
compression ratio when compared with the case where the intra-frame coding
is adopted, because the data compression is realized by making use of
correlation of the picture data between the frames in the case of the
inter-frame coding. However, because of the impossibility of coding the
data independently within each frame according to the inter-frame coding,
an attempt for high-speed reproduction of the picture data by reading out
only the necessary frames is rendered impractical.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the
shortcomings of the prior art technique described above and realize not
only a normal-speed reproduction but also a high-speed reproduction and at
the same time make it possible to record the dynamic picture data for an
extended time period.
In view of the above object, there is provided according to an aspect of
the present invention a picture data recording and reproducing system
which is so arranged as to validate the intra-frame coding completed
within each frame for the picture data of the frames to be extracted for
the use thereof while the inter-frame coding ensuring a high ratio of data
compression is adopted for the data of the other frames.
According to another aspect of the invention, it is proposed that for the
frame to be extracted for use upon high-speed reproduction, the relevant
picture data is coded by adopting a peculiar inter-frame coding scheme
which makes use of the correlation between the frame of concern and the
immediately preceding one in a row of frames as extracted. The peculiar
inter-frame coding (hereinafter referred to as the interleave inter-frame
coding) is completed within each frame row although not completed within
each frame.
Thus, according to the present invention, the picture data is coded by
validating the intra-frame coding or the interleave inter-frame coding for
the frames required for the high-speed reproduction, while the picture
data of the other frames are coded in accordance with the inter-frame
coding method which can assure a high data compression ratio, whereby not
only high-speed reproduction, but extended recording can be realized, to
great advantage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing a structure of the prior art moving
picture recording apparatus;
FIG. 2 is a block diagram showing a structure of the moving picture
reproducing apparatus compatible with the recording apparatus shown in
FIG. 1;
FIG. 3 is a block diagram showing an example of the intra-frame coding type
picture data coding circuit;
FIG. 4 is a block diagram showing a picture data decoding circuit
compatible with the circuit shown in FIG. 3;
FIG. 5 is a diagram illustrating conceptually an example of the inter-frame
coding;
FIG. 6A to 6C are diagrams for illustrating the concept underlying the
prior art picture data recording/reproducing system;
FIG. 7 is a diagram showing only conceptually a structure of a CD-ROM disc
which is one species of the optical disc;
FIG. 8 is a diagram for illustrating conceptually a data format for the
CD-ROM disc;
FIG. 9A to 9C are diagrams for illustrating the concept underlying a moving
picture data recording/reproducing system according to a first embodiment
of the present invention;
FIG. 10 is a block diagram showing schematically a structure of the moving
picture data recording apparatus according to the first embodiment of the
invention;
FIG. 11 is a block diagram showing a structure of the moving picture data
reproducing apparatus compatible with the recording apparatus shown in
FIG. 10;
FIG. 12 is a block diagram showing a picture data coding circuit according
to a first embodiment of the present invention;
FIG. 13 is a block diagram showing a picture data decoding circuit
compatible with the data coding circuit shown in FIG. 12;
FIG. 14 is a block diagram showing a picture data coding circuit according
to a second embodiment of the present invention;
FIG. 15 is a block diagram showing a picture data decoding circuit
compatible with the picture data coding circuit shown in FIG. 14;
FIGS. 16A to 16C are diagrams for illustrating the principle underlying the
moving picture data recording and reproduction performed by the circuits
shown in FIGS. 14 and 15;
FIG. 17 is a block diagram showing the moving picture data coding circuit
according to a third embodiment of the invention;
FIG. 18 is a block diagram showing a picture data decoding circuit
compatible with the coding circuit shown in FIG. 17;
FIGS. 19A to 19C are diagrams for illustrating conceptually the recording
and reproducing operations of the circuits shown in FIGS. 17 and 18;
FIG. 20 is a block diagram of a moving picture data coding circuit
according to a fourth embodiment of the invention;
FIG. 21 is a block diagram showing a picture data decoding circuit
compatible with the coding circuit shown in FIG. 20; and
FIG. 22A, 22B and FIGS. 23A, 23B are diagrams illustrating conceptually the
data recording and reproducing operations of the circuits shown in FIGS.
20 and 21, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following, the present invention will be described in detail in
conjunction with examplary or preferred embodiments thereof by reference
to the attached drawings.
In the first place, description will briefly be made concerning a structure
of an optical disc employed for recording the coded moving picture data as
well as a data format therefor employed in carrying out the invention.
With the CD-ROM disc system, it is intended to record, on a compact disc
(CD) of the same type used as that for audio applications, the computer
data rather than digital audio data.
A structure of this optical disc is shown in FIG. 7. The disc 48 having a
circular configuration is 12 cm in diameter and 1.2 mm thick, wherein a
single continuous helical track 49 having a length of about 5000 m is
formed on a disc surface. Formed sequentially along the track are a series
of pits each having a width of 0.4 .mu.m and a length in a range of 0.9 to
3.3 .mu.m, which length varies in dependence on the value of data. A data
format for the CD-ROM disc is illustrated in FIG. 8. A series of sectors
50 is recorded on the track 49, each sector consisting of 2352 bytes, as
shown at (a) in FIG. 8. More specifically, each of the sectors 50 contains
sync data 51 of 12 bytes (B) used for establishing synchronism, header
data 52 of 4 bytes including address and mode information, blocked
computer data 53 of 2048 bytes, an EDC (error detection code) 54 of 4
bytes based on 32-bit CRC (Cyclic Redundancy Check) code, a reserved area
55 of 8 bytes for future expansion and an ECC (Error Correction Code) 56
of 276 bytes based on Reed-Solomon code, as can be seen in FIG. 8 at (b).
Since the recording on the CD-ROM disc is attended by error correction with
the aid of the EDC 54 and the ECC 56 in addition to the error correction
for the audio CD, the ratio of error which the computer data may suffer
can be compressed to a very low value. Further, because the data transfer
rate is 1.2 Mbps (i.e. about 150 kB/sec), one disc is capable of recording
computer data of about 540 MB. By virtue of the capability of recording a
great amount of data as mentioned above and due to the high data transfer
rate during reproduction, the CD-ROM optical disc can be advantageously
used in a moving picture recording/reproducing system for recording and
reproducing coded moving picture data.
FIGS. 9A to 9C are views illustrating, by way of example, a format for
recording the coded moving picture data and a method of reproducing data
on the assumption that the optical disc 48 mentioned above is employed in
carrying out the present invention. More specifically, FIG. 9A shows the
disposition or array of the coded moving picture data recorded on the
track 49 of the optical disc 48, and FIGS. 9B and 9C are views
illustrating a method of reproducing the coded data. As can be seen in
FIG. 9A, the coded data of the individual frames 61, compressed
significantly as a result of the inter-frame coding, are recorded in the
order of the frame numbers along with the intra-frame coded data of the
frames 60 recorded every third frame. Upon reproduction at the normal
speed, the inter-frame coded data of the frame 61 is read out frame by
frame (i.e. on the frame basis) in the order of the frame numbers, as
shown in FIG. 9B. On the other hand, in the case of reproduction at the
trebled speed, the data of the frames 60, coded by the interleave
intra-frame coding method, are sequentially read out. In this manner, both
the normal speed reproduction and the trebled speed reproduction can be
selectively realized.
FIGS. 10 and 11 show a picture data recording apparatus and a reproducing
apparatus according to the invention which correspond to those shown in
FIG. 1 and FIG. 2, respectively. In FIGS. 10 and 11, parts corresponding
to those shown in FIGS. 1 and 2 are denoted by the same reference symbols,
and the following description is directed only to those parts which are
newly added.
Referring to FIG. 10, the frame memory 17 outputs onto lines 171 and 172
picture data stored therein together with the corresponding frame numbers
thereof. The frame number data on the line 172 is transmitted through the
picture data coding circuit 18 onto a line 175. A data multiplexer circuit
173 adds the frame number data on the line 175 to the coded data of each
corresponding frame outputted from the picture data coding circuit 18 onto
the line 19, the resultant data being then stored in the buffer memory 20.
On the other hand, in the reproducing apparatus shown in FIG. 11,
reproduction mode data assuming a value of "0" or "1" in dependence on
whether the normal speed reproduction or the high speed reproduction is
selected is inputted to a line 177. The optical disk reading circuit 21 is
operated either in the normal speed reproduction mode or in the; high
speed reproduction mode in response to the reproduction mode data. A data
separating circuit 178 separates the reproduced data into coded picture
data and frame number data. The picture data decoding circuit 26
reproduces the picture data on the basis of the coded picture data and the
frame number data supplied from the data separation circuit 178 and the
reproduction mode data.
FIG. 12 is a block diagram showing in detail a circuit configuration of the
picture data coding circuit according to an embodiment of the present
invention employed in the moving picture data recording apparatus
described above, and FIG. 13 is a block diagram showing in detail the
structure of the picture data decoding circuit employed in the dynamic
picture reproducing apparatus according to the invention. The picture data
coding circuit shown in FIG. 12 corresponds to the circuit 18 shown in
FIG. 10, while the picture data decoding circuit shown in FIG. 13
corresponds to the circuit 26 shown in FIG. 11. Now, referring to FIG. 12,
a reference numeral 1 denotes an input line for the picture data, 2
denotes an intra-frame coding circuit, 3 denotes an inter-frame coding
circuit, 4 denotes a frame memory, 5 denotes a data multiplexing circuit,
6 denotes a frame number data transfer line, 7 denotes a coding scheme
selection control circuit, and numeral 8 denotes a coded data transfer
line. In FIG. 13, reference numeral 40 denotes a coded data transfer
(input) line, 41 denotes an intra-frame decoding circuit, 42 denotes an
inter-frame decoding circuit, 43 denotes a frame memory, 44 denotes a data
switching circuit, 45 denotes a transfer path line for the frame number
data, 46 denotes a decoding scheme selection cont | | |
