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Claims  |
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We claim:
1. An apparatus for generating from a variable-rate coded signal a
multiplexed signal for recording on a recording medium, the multiplexed
signal being adapted to enable intrinsically-decodable signal portions
included at irregular intervals in the variable-rate coded signal to be
successively reproduced for decoding when the recording medium is searched
at high speed, the variable-rate coded signal being generated by
compressing a digital input signal using a variable compression ratio, the
apparatus comprising:
flag signal generating means for generating a flag signal indicating each
of the intrinsically-decodable signal portions in the variable-rate coded
signal;
determining means, operating in response to the flag signal, for
determining location information for each one of the
intrinsically-decodable signal portions, the location information for the
one of the intrinsically-decodable signal portions indicating a location
of an adjacent one of the intrinsically-decodable signal portions;
decodable signal pointer generating means for receiving the location
information from the determining means, and for generating a decodable
signal pointer for each one of the intrinsically-decodable signal
portions, the decodable signal pointer including the location information
determined by the determining means for the one of the
intrinsically-decodable signal portions; and
multiplexing means for multiplexing the decodable signal pointer generated
by the decodable signal generating means for each one of the
intrinsically-decodable signal portions with the variable-rate coded
signal to produce the multiplexed signal, the multiplexing means operating
to locate the decodable signal pointer adjacent to the one of the
intrinsically-decodable signal portions in the multiplexed signal.
2. The apparatus of claim 1, wherein the multiplexing means operates to
locate the decodable signal pointer for each one of the
intrinsically-decodable signal portions immediately ahead of the one of
the intrinsically-decodable signal portions in the multiplexed signal.
3. The apparatus of claim 2, wherein:
the digital input signal is a digital video signal including plural
pictures, each of the pictures being compressed in one of an intra-picture
mode and an inter-picture mode; and
the flag signal generating means includes:
receiving means for receiving the variable-rate coded signal,
identifying means for analyzing the variable-rate coded signal received by
the receiving means to identify therein signal portions respectively
resulting from compressing pictures in the intra-picture mode as the
intrinsically-decodable signal portions, and
means for generating the flag signal in response to each of the signal
portions identified by the identifying means as the
intrinsically-decodable signal portions.
4. The apparatus of claim 2, wherein:
the apparatus additionally comprises means for recording the multiplexed
signal on a recording medium; and
the determining means is for determining location information indicating a
location on the recording medium of the decodable signal pointer of the
adjacent one of the intrinsically-decodable signal portions in the
multiplexed signal.
5. The apparatus of claim 2, wherein:
the apparatus additionally comprises means for recording the multiplexed
signal on a recording medium; and
the determining means is for determining location information indicating
locations on the recording medium of the decodable signal pointers of ones
of the intrinsically-decodable signal portions successively disposed about
the one of the intrinsically-decodable signal portions in the multiplexed
signal.
6. The apparatus of claim 1, wherein:
the apparatus additionally means for receiving an uncompressed digital
video signal comprising plural pictures; and
the flag signal generating means includes compressing means for compressing
the uncompressed digital video signal using a variable compression ratio
to provide the variable-rate coded signal, the compressing means
compressing each of the pictures of the uncompressed digital video signal
in one of an intra-picture compression mode and an inter-picture
compression mode, each of the pictures compressed in the intra-picture
compression mode providing one of the intrinsically-decodable signal
portions of the variable-rate coded signal, the compressing means
additionally generating the flag signal for each of the pictures
compressed in the intra-picture compression mode.
7. The apparatus of claim 1, wherein the decodable signal pointer
generating means is for:
generating an entry packet as the decodable signal pointer for each one of
the intrinsically-decodable signal portion; and including the location
information for the one of the intrinsically-decodable signal portions in
the entry packet.
8. The apparatus of claim 7, wherein the multiplexing means is for
multiplexing the entry packet for each one of the intrinsically-decodable
signal portions with the variable-rate coded signal, and operates to
locate the entry packet immediately ahead of the one of the
intrinsically-decodable signal portions in the multiplexes signal.
9. The apparatus of claim 8, wherein:
the apparatus additionally comprises:
recording means for recording the multiplexed signal on the recording
medium in a first recording operation, and
storage means for storing a location on the recording medium of the entry
packet for each of the intrinsically-decodable signal portions; and
the recording means is additionally for recording on the recording medium,
in a second recording operation, ones of the locations read from the
storage means into the entry packet for each of the
intrinsically-decodable signal portions recorded on the recording medium
in the first recording operation.
10. The apparatus of claim 9, wherein:
in the first recording operation, the recording means records into the
entry packet for each one of the intrinsically-decodable signal portions
the locations of a predetermined number of the entry packets preceding the
entry packet for the one of the intrinsically-decodable signal portions in
the multiplexed signal; and
in the second recording operation, the recording means records into the
entry packet for each one of the intrinsically-decodable signal portions
the locations of a predetermined number of the entry packets following the
entry packet for the one of the intrinsically-decodable signal portions in
the multiplexed signal.
11. The apparatus of claim 8, wherein:
the decodable signal pointer generating means comprises:
accumulating means for accumulating a predetermined quantity of the
variable-rate coded signal, and
means, responsive to the flag signal, for generating a control signal when
the predetermined quantity of the variable-rate coded signal accumulated
in the accumulating means includes one of the intrinsically-decodable
signal portions; and
the decodable signal pointer generating means generates each of the entry
packets in response to the control signal.
12. The apparatus of claim 1, wherein the decodable signal pointer
generating means is for generating subcode as the decodable signal pointer
for each one of the intrinsically-decodable signal portions, the subcode
representing the location information.
13. The apparatus of claim 12, wherein:
the multiplexing means includes means for dividing the variable-rate coded
signal into sectors, each of the sectors having a beginning, and for
adding a sector header to the beginning of each of the sectors; and
the multiplexing means includes subcode inserting means for inserting the
subcode for the one of the intrinsically-decodable signal portions into
the sector header of one of the sectors accommodating the one of the
intrinsically-decodable signal portions to multiplex the decodable signal
pointer for the one of the intrinsically-decodable signal portions with
the variable-rate coded signal.
14. The apparatus of claim 13, wherein:
the one of the intrinsically-decodable signal portions is accommodated in
consecutive ones of the sectors; and
the subcode inserting means is additionally for distributing the subcode
for the one of the intrinsically-decodable signal portions among the
sector headers of the consecutive ones of the sectors accommodating the
one of the intrinsically-decodable signal portions.
15. The apparatus of claim 13, wherein:
the apparatus additionally comprises means for recording the multiplexed
signal on the recording medium; and
the determining means is for determining location information indicating a
location on the recording medium of an adjacent one of the sectors having
a sector header that includes subcode as a decodable signal pointer.
16. A method for generating from a variable-rate coded signal a multiplexed
signal for recording on a recording medium, the multiplexed signal being
adapted to enable intrinsically-decodable signal portions included at
irregular intervals in the variable-rate coded signal to be reproduced and
decoded when the recording medium is searched at high speed, the
variable-rate coded signal being generated by compressing a digital input
signal using a variable compression ratio, the method comprising steps of:
generating a flag signal indicating each of the intrinsically-decodable
signal portions in the variable-rate coded signal;
determining, for each one of the intrinsically-decodable signal portions
indicated by the flag signal in the variable-rate coded signal, location
information indicating a location of an adjacent one of the
intrinsically-decodable signal portions;
generating, in response to the location information determined in the
determining step, a decodable signal pointer for each one of the
intrinsically-decodable signal portions, the decodable signal pointer
including the location information for the adjacent one of the
intrinsically-decodable signal portions; and
multiplexing the decodable signal pointer generated for each one of the
intrinsically-decodable signal portions in the generating step with the
variable-rate coded signal to produce the multiplexed signal, and to
locate the decodable signal pointer adjacent to the one of the
intrinsically-decodable signal portions in the multiplexed signal.
17. The method of claim 16, wherein, in the multiplexing step, the
decodable signal pointer for each one of the intrinsically-decodable
signal portions is multiplexed with the variable-rate coded signal to
locate the decodable signal pointer for the one of the
intrinsically-decodable signal portions immediately ahead of the one of
the intrinsically-decodable signal portions in the multiplexed signal.
18. The method of claim 17, wherein:
the digital input signal is a digital video signal including plural
pictures, each of the pictures being compressed in one of an intra-picture
mode and an inter-picture mode; and
the step of generating a flag signal includes steps of:
receiving the variable-rate coded signal,
identifying, in the variable-rate coded signal, signal portions
respectively resulting from compressing pictures in the intra-picture mode
as the intrinsically-decodable signal portions, and
generating the flag signal in response to the signal portions identified in
the identifying step as the intrinsically-decodable signal portions.
19. The method of claim 17, wherein:
the method additionally comprises a step of recording the multiplexed
signal on the recording medium; and
the determining step determines location information indicating a location
on the recording medium of the decodable signal pointer of the adjacent
one of the intrinsically-decodable signal portions signal-type marker, the
additional signal-type marker being proximate to the in the multiplexed
signal.
20. The method of claim 17, wherein:
the method additionally comprises a step of recording the multiplexed
signal on the recording medium; and
the determining step determines location information indicating locations
on the recording medium of the decodable signal pointers of ones of the
intrinsically-decodable signal portions successively disposed about the
one of the intrinsically-decodable signal portions in the multiplexed
signal.
21. The method of claim 16, wherein:
the method additionally comprises a step of receiving an uncompressed
digital video signal comprising plural pictures;
the flag generating step includes steps of:
compressing the uncompressed digital video signal using a variable
compression ratio to provide the variable-rate coded signal, each of the
pictures of the uncompressed digital video signal being compressed in one
of an intra-picture compression mode and an inter-picture compression
mode, each of the pictures compressed in the intra-picture compression
mode providing one of the intrinsically-decodable signal portions of the
variable-rate coded signal, and
generating the flag signal for each of the pictures compressed in the
intra-picture compression mode.
22. The method of claim 16, wherein the step of generating the decodable
signal pointer includes steps of:
generating an entry packet as the decodable signal pointer for each one of
the intrinsically-decodable signal portions; and
including the location information for the one of the
intrinsically-decodable signal portions in the entry packet.
23. The method of claim 22, wherein the multiplexing step multiplexes the
entry packet for each one of the intrinsically-decodable signal portions
with the variable-rate coded signal to locate the entry packet immediately
ahead of the one of the signal portions in the multiplexed signal.
24. The method of claim 23, wherein:
the method additionally comprises steps of:
recording the multiplexed signal on the recording medium in a first
recording operation,
storing a location on the recording medium of the entry packet for each of
the intrinsically-decodable signal portions, and
recording on the recording medium, in a second recording operation, ones of
the locations stored in the storing step into the entry packet for each of
the intrinsically-decodable signal portions recorded on the recording
medium in the first recording operation.
25. The method of claim 24, wherein:
in the first recording operation, the recording step records into the entry
packet for each one of the intrinsically-decodable signal portions the
locations of a predetermined number of entry packets preceding the entry
packet of the one of the intrinsically-decodable signal portions in the
multiplexed signal; and
in the second recording operation, the recording step records into the
entry packet for each one of the intrinsically-decodable signal portions
the locations of a predetermined number of entry packets following the
entry packet for the one of the intrinsically-decodable signal portions in
the multiplexed signal.
26. The method of claim 23, wherein:
the step of generating a decodable signal pointer comprises steps of:
accumulating a predetermined quantity of the variable-rate coded signal,
and
generating, in response to the flag signal, a control signal when the
predetermined quantity of the variable-rate coded signal accumulated in
the accumulating means includes one of the intrinsically-decodable signal
portions; and
in the step of generating a decodable signal pointer, the entry packet is
generated in response to the control signal.
27. The method of claim 16, wherein the step of generating the decodable
signal pointer includes a step of generating subcode the decodable signal
pointer for each of the intrinsically-decodable signal portions, the
subcode representing the location information of the one of the
intrinsically-decodable signal portions.
28. The method of claim 27, wherein the multiplexing step includes steps
of:
dividing the variable-rate coded signal into sectors, each of the sectors
beginning with a sector header; and
inserting the subcode into the sector header of one of the sectors
accommodating at least part of the one of the intrinsically-decodable
signal portions to multiplex the decodable signal pointer for the one of
the intrinsically-decodable signal portions with the variable-rate coded
signal.
29. The method of claim 28, wherein, in the multiplexing step:
the one of the intrinsically-decodable signal portions is accommodated in
consecutive ones of the sectors; and
in the inserting step, the subcode is distributed among the sector headers
of ones of the consecutive ones of the sectors accommodating the one of
the intrinsically-decodable signal portions.
30. The method of claim 28, wherein:
the method additionally comprises a step of recording the multiplexed
signal on the recording medium; and
the determining step determines location information indicating a location
on the recording medium of an adjacent one of the sectors having a sector
header that includes subcode as a decodable signal pointer.
31. Apparatus for reproducing a multiplexed signal recorded on a recording
medium to effect a high-speed search, the multiplexed signal including
intrinsically-decodable signal portions of a variable-rate coded signal at
irregular intervals, and a decodable signal pointer adjacent each of the
intrinsically-decodable signal portions, the apparatus effecting the
high-speed search by successively reproducing and decoding the
intrinsically-decodable signal portions in the multiplexed signal in
response to the decodable signal pointers, the apparatus comprising:
reproducing means for reproducing part of the multiplexed signal from a
read position on the recording medium, the part of the multiplexed signal
including one of the intrinsically-decodable signal portions of the
variable-rate coded signal and the decodable signal pointer adjacent
thereto;
demultiplexing means for receiving the part of the multiplexed signal from
the reproducing means, and for demultiplexing the part of the multiplexed
signal to provide the one of the intrinsically-decodable signal portions
of the variable-rate coded signal and the decodable signal pointer;
extracting means for receiving the decodable signal pointer from the
demultiplexing means, and for extracting location information from the
decodable signal pointer, the location information indicating a location
of an adjacent one of the intrinsically-decodable signal portions; and
control means for causing the reproducing means to change the read position
to the location of the adjacent one of the intrinsically-decodable signal
portions in response to the location information extracted by the
extracting means from the decodable signal pointer and indicating the
location of the adjacent one of the intrinsically-decodable signal
portions.
32. The reproducing apparatus of claim 31, wherein:
the apparatus additionally comprises search rate selecting means for
selecting a search rate at which the recording medium is searched;
the extracting means is for extracting location information indicating
locations on the recording medium of the decodable signal pointers of a
number of the intrinsically-decodable signal portions successively
preceding and following the one of the intrinsically-decodable signal
portions;
the extracting means includes location selecting means, operating in
response to the search rate selected by the search rate selecting means,
for selecting from the location information extracted from the decodable
signal pointer the location of the decodable signal pointer of one of the
number of intrinsically-decodable signal portions as a selected location;
and
the control means causes the reproducing means to change the read position
in response to the selected location selected by the location selecting
means.
33. The reproducing apparatus of claim 31, wherein the apparatus
additionally comprises:
storage means for storing the location information extracted by the
extracting means from the decodable signal pointer; and
means, operating in response to a search command, for reading the location
information from the storage means, and for feeding the location
information to the control means.
34. The reproducing apparatus of claim 31, wherein:
the apparatus additionally includes decoding means for decoding the
intrinsically-decodable signal portions of the variable-rate coded signal
demultiplexed by the demultiplexed means from the multiplexed signal
reproduced by the reproducing means, the decoding means generating a
picture of an output signal from each one of the intrinsically-decodable
signal portions.
35. The reproducing apparatus of claim 34, wherein the decoding means
generates the picture of the output signal from the one of the
intrinsically-decodable signal portions demultiplexed by the
demultiplexing means from the part of the multiplexed signal reproduced by
the reproducing means at each read position on the recording medium.
36. The reproducing apparatus of claim 31, wherein:
the variable-rate coded signal includes signal portions, the signal
portions including the intrinsically-decodable signal portions, each of
the signal portions being derived by compressing a picture of a video
signal in one of an intra-picture mode and an inter-picture mode; and
the demultiplexing means functions to demultiplex the decodable signal
pointer from a point immediately preceding each of the
intrinsically-decodable signal portions in the multiplexed signal, each of
the intrinsically-decodable signal portions being derived from a picture
compressed in the intra-picture mode.
37. The reproducing apparatus of claim 31, wherein the demultiplexing means
functions to demultiplex the part of the multiplexed signal received from
the reproducing means to provide an entry packet for the one of the
intrinsically-decodable signal portions, the entry packet including the
decodable signal pointer for the one of the intrinsically-decodable signal
portions.
38. The reproducing apparatus of claim 37, wherein, the demultiplexing
means functions to demultiplex the entry packet for the one of the
intrinsically-decodable signal portions from a point immediately preceding
the one of the intrinsically-decodable signal portions in the multiplexed
signal.
39. The reproducing apparatus of claim 37, wherein:
the variable-rate coded signal includes signal portions, the signal
portions including the intrinsically-decodable signal portions, each of
the signal portions being derived by compressing a picture of a video
signal in one of an intra-picture mode and an inter-picture mode; and
the demultiplexing means functions to demultiplex the entry packet for the
one of the intrinsically-decodable signal potions from a point immediately
preceding the one of the intrinsically-decodable signal portions in the
multiplexed signal, the one of the intrinsically-decodable signal portions
being derived from a picture compressed in the intra-picture mode.
40. The reproducing apparatus of claim 31, wherein:
the multiplexed signal is divided into sectors, each of the sectors
beginning with a sector header; and
the decodable signal pointer is represented by subcode included in the
sector header of one of the sectors accommodating one of the intrinsically
decodable signal portions.
41. The reproducing apparatus of claim 40, wherein the demultiplexing means
functions to demultiplex the subcode representing the decodable signal
pointer from the sector header of one of the sectors accommodating the one
of the intrinsically-decodable portions.
42. The reproducing apparatus of claim 41, wherein the demultiplexing means
additionally functions to demultiplex the subcode from the sector headers
of consecutive ones of the sectors accommodating the one of the
intrinsically-decodable signal portions.
43. The reproducing apparatus of claim 40, wherein:
the variable-rate coded signal includes signal portions, the signal
portions including the intrinsically-decodable signal portions, each of
the signal portions being derived by compressing a picture of a video
signal in one of an intra-picture mode and an inter-picture mode; and
the demultiplexing means functions to demultiplex the subcode from sector
headers of consecutive ones of the sectors accommodating the one of the
intrinsically-decodable signal portions, the one of the
intrinsically-decodable signal portions being derived by compressing a
picture in the intra-picture mode.
44. Method of reproducing a multiplexed signal recorded on a recording
medium to effect a high-speed search, the multiplexed signal including
decodable portions of a variable-rate coded signal at irregular intervals,
and a decodable signal pointer adjacent each of the
intrinsically-decodable signal portions, the apparatus effecting a
high-speed search by successively reproducing and decoding the
intrinsically-decodable signal portions in the multiplexed signal in
response to position information in the decodable signal pointers, the
method comprising repeating a sequence of steps including steps of:
reproducing part of the multiplexed signal from a read position on the
recording medium, the part of the multiplexed signal including one of the
intrinsically-decodable signal portions and the decodable signal pointer
adjacent thereto;
demultiplexing the part of multiplexed signal reproduced in the reproducing
step to provide the one of the intrinsically-decodable signal portions of
the variable-rate coded signal and the decodable signal pointer adjacent
thereto;
extracting the location information from the decodable signal pointer
demultiplexed by the demultiplexing step, the location information
indicating a location of an adjacent one of the intrinsically-decodable
signal portions; and
changing the read position to the location of the adjacent one of the
intrinsically-decodable signal portions on the recording medium in
response to the location information extracted in the extracting step from
the decodable signal pointer, the location information indicating the
location of the adjacent one of the intrinsically-decodable signal
portions.
45. The reproducing method of claim 44, wherein:
the method additionally comprises a step of selecting a search rate at
which the recording medium is searched;
the extracting step extracts location information indicating locations on
the recording medium of the decodable signal pointers of a number of the
intrinsically-decodable signal portions successively preceding and
following the one of the intrinsically-decodable signal portions;
the extracting step additionally includes a step of selecting from the
location information extracted in the extracting step the location of the
decodable signal pointer of one of the number of intrinsically-decodable
signal portions, the location of the intrinsically-decodable signal
pointer being selected in response to the search rate selected in the
search rate selecting step; and
in the step of changing the read position, the read position is changed to
the read position indicated by the location selected in the location
selecting step.
46. The reproducing method of claim 44, wherein:
the method additionally comprises steps of:
providing a storage device,
storing the location information extracted in the extracting step from the
decodable signal pointer in the storage device, and
in response to a search command, reading from the search device the stored
location information; and
in the step of changing the read position, the read position is changed in
response to the location information read from the storage device.
47. The reproducing method of claim 44, wherein the sequence of steps
additionally includes a step of decoding the intrinsically-decodable
signal portions of the variable-rate coded signal demultiplexed in the
demultiplexing step from the part of the multiplexed signal reproduced in
the reproducing step, the decoding step generating a picture of an output
signal from each of the intrinsically-decodable signal portions.
48. The reproducing method of claim 47, wherein when the sequence of steps
is repeated, after the demultiplexing step, the step of decoding the
intrinsically-decodable signal portion decodes the intrinsically-decodable
signal portion demultiplexed from the part of the multiplexed signal
reproduced from the read position in the reproducing step to generate one
picture of the output signal.
49. The reproducing method of claim 47, wherein the variable-rate coded
signal includes signal portions, including the intrinsically-decodable
signal portions, each of the signal portions being derived by compressing
a picture of a video signal in one of an intra-picture mode and an
inter-picture mode, the intrinsically-decodable signal portions being
derived by compressing a picture in the intra-picture mode, and wherein:
the demultiplexing step operates to demultiplex the decodable signal
pointer from a point immediately preceding the intrinsically-decodable
signal portion in the part of the multiplexed signal reproduced in the
reproducing step.
50. The reproducing method of claim 44, wherein, in the multiplexed signal,
the decodable signal pointer is included in an entry packet.
51. The reproducing method of claim 50, wherein, in the demultiplexing
step, the entry packet for each one of the intrinsically-decodable signal
portions is demultiplexed from a point immediately preceding the one of
the signal portions in the multiplexed signal.
52. The reproducing method of claim 50, wherein:
in the multiplexed signal, the variable-rate coded signal includes signal
portions, the signal portions including the intrinsically-decodable signal
portions, each of the signal portions being derived by compressing a
picture of a video signal, each picture being compressed in one of an
intra-picture mode and an inter-picture mode; and
the demultiplexing step demultiplexes the entry packet for each one of the
intrinsically-decodable signal portions from a point immediately preceding
the one of the intrinsically-decodable signal portions in the multiplexed
signal, the one of the intrinsically-decodable signal portions being
derived from a picture compressed in the intra-picture mode.
53. The reproducing method of claim 44, wherein:
the multiplexed signal is divided into sectors, each of the sectors
beginning with a sector header; and
the decodable signal pointer of each one of the intrinsically-decodable
signal portions is represented by subcode included in the sector header of
at least one of the sectors accommodating the one of the
intrinsically-decodable signal portions.
54. The reproducing method of claim 53, wherein the demultiplexing step
demultiplexes the subcode representing the decodable signal pointer of
each one of the intrinsically-decodable signal portions from the sector
header of one of the sectors accommodating the one of the
intrinsically-decodable signal portions.
55. The reproducing method of claim 53, wherein the demultiplexing step
demultiplexes the subcode representing the decodable signal pointer of
each one of the intrinsically-decodable signal portions from the sector
headers of consecutive ones of the sectors accommodating the one of the
intrinsically-decodable signal portions.
56. The reproducing method of claim 53, wherein:
in the multiplexed signal, the variable-rate coded signal includes signal
portions, the signal portions including the intrinsically-decodable signal
portions, each of the signal portions being derived by compressing a
picture of a video signal, in one of an intra-picture mode and an
inter-picture mode; and
the demultiplexing step demultiplexes the subcode representing the
decodable signal pointer of each one of the intrinsically-decodable signal
portions from the sector headers of consecutive ones of the sectors
accommodating the one of the intrinsically-decodable signal portions, the
one of the intrinsically-decodable signal portions being derived by
compressing a picture in the intra-picture mode.
57. A method of recording an information signal in a recording medium to
enable portions of the information signal to be reproduced from the
recording medium during a search thereof, the method comprising steps of:
providing a recording medium; and
recording a multiplexed signal in the recording medium, the multiplexed
signal being generated by steps including:
providing a variable-rate coded signal comprising plural signal portions,
the signal portions including intrinsically-decodable signal portions at
irregular intervals,
determining, for each one of the intrinsically-decodable signal portions of
the variable-rate coded signal, location information indicating a location
on the recording medium of an adjacent one of the intrinsically-decodable
signal portions, and
multiplexing the variable-rate coded signal and decodable signal pointers
to locate one of the decodable signal pointers adjacent each one of the
intrinsically-decodable signal portions, the one of the decodable signal
pointers including the location information for the one of the
intrinsically-decodable signal portions.
58. The recording method of claim 57, wherein, in the step of recording the
multiplexed signal, the decodable signal pointer is recorded in the
recording medium immediately preceding the one of the
intrinsically-decodable signal portions.
59. The recording method of claim 57, wherein the determining step
determines location information indicating locations on the recording
medium of the decodable signal pointers of plural ones of the
intrinsically-decodable signal portions successively disposed about the
one of the intrinsically-decodable signal portions.
60. The recording method of claim 57, wherein:
in the step of providing a variable-rated coded signal, each of the
intrinsically-decodable signal portions has a beginning;
the determining step includes a step of generating an entry packet for each
one of the decodable signal portions as the decodable signal pointer, the
entry packet including the location information; and
in the multiplexing step:
the variable-rate coded signal is divided into packs comprising packets for
recording on the recording medium, and
the entry packet for the one of the intrinsically-decodable signal portion
is multiplexed to locate the entry packet immediately preceding the one of
the packets including the beginning of the one of the
intrinsically-decodable signal portions.
61. The recording method of claim 60, wherein the step of providing the
variable-rate coded signal includes steps of:
providing a video input signal including pictures; and
compressing each of the pictures of the video input signal in one of an
intra-picture mode and an inter-picture mode to generate a respective one
of the signal portions of the variable-rate coded signal, each of the
intrinsically-decodable signal portions being one of the signal portions
resulting from compressing one of the pictures in the intra-picture mode.
62. The recording method of claim 57, wherein:
in the step of providing a variable-rate coded signal, each of the
intrinsically-decodable signal portions has a beginning;
in the determining step, subcode is generated for each of the
intrinsically-decodable signal portions as the decodable signal pointer;
and
in the multiplexing step:
the multiplexed signal is divided into sectors for recording on the
recording medium, each of the sectors beginning with a sector header, the
sector header accommodating subcode, and
the subcode for the one of the intrinsically-decodable signal portions is
included in the sector header of at least the one of the sectors
accommodating the beginning of the one of the intrinsically-decodable
signal portions.
63. The recording method of claim 62, wherein the step of providing the
variable-rate coded signal includes step of:
providing a video input signal including pictures; and
compressing each of the pictures of the video input signal in one of an
intra-picture mode and an inter-picture mode to generate a respective one
of the signal portions of the variable-rate coded signal, each of the
intrinsically-decodable signal portions being one of the signal portions
resulting from compressing one of the pictures in the intra-picture mode. |
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Claims |
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Description |
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FIELD OF THE INVENTION
This invention relates to an apparatus and method for processing a
variable-rate coded signal prior to recording so that high-speed searching
can be carried out on a recording medium on which the processed signal is
recorded. The invention also relates to an apparatus and method for
performing a high-speed search on a medium on which a processed
variable-rate coded signal is recorded. Finally, the invention relates to
a recording of the processed variable-rate coded signal.
BACKGROUND OF THE INVENTION
Examples of a conventional recording apparatus and a conventional
reproducing apparatus are shown in FIGS. 1 and 2. Referring to FIG. 1, the
digital video signal to be recorded is compressed and coded by the video
encoder 1, and then fed into the video signal buffer 4 in the multiplexing
circuit 3. The digital audio signal to be recorded is compressed and coded
by the audio encoder 2, and then fed into to the audio signal buffer 5 in
the multiplexing circuit 3.
The output terminals of the signal buffers 4 and 5 are connected to the
input terminals E1 and E2 of the switching circuit 6, respectively. The
output terminal F of the switching circuit 6 is connected to the input
terminal of the header addition circuit 7. The output of the header
addition circuit 7 is supplied to the digital storage medium (DSM) 10,
which includes, for example, a magneto-optical disk or a magnetic disk,
e.g., a hard disk. The control circuit 8 receives system clock signals
from the multiplexing system clock generation circuit 9, and causes the
switching circuit 6 to connect the output terminal F to the input
terminals E1 and E2 successively at a predetermined time interval. This
successively fetches video signal bytes from the video signal buffer 4 and
audio signal bytes from the audio signal buffer 5, thereby time division
multiplexing the audio and video signals.
The control circuit 8 causes the switching circuit 6 and the header
addition circuit 7 to produce a multiplexed signal having the multiplexing
system format set forth in the ISO 11172 (MPEG) standard. The multiplexed
signal includes one or more packs (PACK) and one ISO.sub.-- 11172.sub.--
end.sub.-- code, as shown in FIG. 3. The ISO.sub.-- 11172.sub.--
end.sub.-- code is a code of 32 bits and is, when represented in the
hexadecimal notation, 0x000001B9. The prefix 0x indicates hexadecimal
notation, where x is indeterminate.
Each pack includes a header, which includes a Pack.sub.-- Start.sub.--
Code, a System Clock Reference (SCR), a MUX.sub.-- Rate, and one or more
packets (Packet). The Pack.sub.-- Start.sub.-- Code of the header is a
code of 32 bits and is 0x 000001B4, the prefix 0x once again indicating
hexadecimal notation. A pack has a variable length up to a maximum of
2,048 bytes.
Each packet includes a header, which includes a Packet.sub.-- Start.sub.--
Code.sub.-- Prefix, a stream.sub.-- ID, a Packet.sub.-- length, a
Presentation Time Stamp (PTS), a Decoding Time Stamp (DTS), and a packet
data portion. The Packet.sub.-- Start.sub.-- Code.sub.-- Prefix is a code
of 24 bits and is 0x000001. The Stream.sub.-- ID is a code of 8 bits and
indicates the type of the packet, as shown in FIG. 4. The Packet.sub.--
length (16 bits) indicates the length of the packet following it.
The packet data portion of each packet consists of a portion of the digital
audio signal (when the stream type indicates an audio stream) or a portion
of the video signal (when the stream type indicates a video stream).
Further, since each audio stream can have one of 32 different
stream.sub.-- IDs and the each video stream can have one of up to 16
different stream.sub.-- IDs, up to 32 different audio signals and up to 16
different video signals can be multiplexed.
A reserved stream includes, for example, subtitle data. Private.sub.--
stream.sub.-- l and private.sub.-- stream.sub.-- 2 do not have defined
applications. A padding.sub.-- stream is used to increase the amount of
data.
The control circuit 8 (FIG. 1) controls adding headers and reading signal
bytes using an algorithm such as that shown, for example, in FIG. 5 so
that a total of 2,048 bytes are included in each pack in accordance with
the format described above.
Referring to FIGS. 1 and 5, at step S1, the control circuit 8 instructs the
header addition circuit 7 to generate a pack header. Then, at step S2, the
control circuit 8 waits until the sum of M4 and M5 is equal to or greater
than the number of signal bytes D included in one pack. In other words,
the control circuit 8 waits until the total number of signal bytes
accumulated in the signal buffers 4 and 5 is equal to the number of bytes
that can be accommodated by one pack, M4 represents the number of bytes of
video signal written in the video signal buffer 4, and M5 represents the
number of bytes of audio signal written in the audio signal buffer 5. D
represents a total number of signal b | | |
