JPH11122579A - Digital information recording method, recording and reproducing method, signal generator and decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain conventional reproduction and variable speed reproduction with excellent operating convenience by adding information denoting discontinuity of channel information to digital compression signal for variable speed reproduction when channel information is changed or at recording start and recording multiply the sum signal, re-retrieving the channel information at reproduction and decoding the digital compression signal according to the result. SOLUTION: A control circuit 40 discriminates the recording mode based on detected data to set the operating mode for a recording signal processing circuit 120 and a servo circuit 130. The recording signal processing circuit 120 applies recording signal processing to variable speed reproduction data and data received from a 2nd information separation circuit 35 to reproduce the recording signal. The recording signal is recorded on a recording medium 148 via magnetic heads 145a, 145b placed on a cylinder 140. In the case of reproduction, data are reproduced at first in an optional reproduction mode and detects ID information and a sub code or the like added at recording from the received reproduction data to set again the reproduction mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital information recording method for recording a digital signal obtained by time-division multiplexing digital compressed information and channel information as a digital signal. The present invention relates to a digital information recording / reproducing method for recording and reproducing a time-division multiplexed digital signal as a digital signal. Further, the present invention relates to a decoding device for selecting and decoding a predetermined signal from a digital signal in which a plurality of digital compression information and channel information are time-division multiplexed, Digis with variable speed playback Le information recording method, a digital information recording and reproducing method, the signal generating device, a decoding device.

[0002]

2. Description of the Related Art As a technique for recording and reproducing a compressed digital signal, a digital signal recording apparatus is disclosed in Japanese Patent Laid-Open No. 8-27.
No. 3305. This digital signal recording apparatus describes that signals for normal reproduction and variable speed reproduction are recorded.

[0003]

SUMMARY OF THE INVENTION The aforementioned Japanese Patent Application Laid-Open No. 8-27 is disclosed.
No. 3305 describes that data for normal reproduction and variable speed reproduction are recorded, but the decoding processing of the reproduced compressed digital signal is not sufficiently considered, and the decoding processing at the discontinuous point of the digital signal generated at the time of recording is not performed. Had an inconvenience.

An object of the present invention is to provide a digital broadcast receiving apparatus, a digital information recording / reproducing apparatus capable of recording and reproducing digital broadcast signals as digital signals, and further capable of variable speed reproduction, and a digital compressed signal decoding apparatus. An object of the present invention is to realize a digital information recording method, a recording / reproducing method, a signal generation device, and a decoding device that can be connected with good connection.

[0005]

In order to achieve the above object, information indicating discontinuity of channel information is added at the start of recording or at a point where channel information changes, and recording is performed on a recording medium. At the time of reproduction, the above object can be achieved by performing decoding processing using a digital compressed signal and information indicating the discontinuity.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration example of the present invention in a digital information recording / reproducing system for receiving a digital broadcast signal in which a plurality of digital compressed information is time-division multiplexed, and recording and reproducing the digital signal as it is. FIG.

In FIG. 1, 1 is an input terminal of a digital broadcast signal, 10 is a tuner, 20 is a selection circuit, 30 is a first information separation circuit, 35 is a second information separation circuit, 40
Is a control circuit, 45 is an operation terminal, 50 is a decoder, 5 is a video signal output terminal, 120 is a recording signal processing circuit that generates a predetermined recording signal, 130 is a servo circuit, 140 is a cylinder, 145a and 145b are magnetic heads Reference numeral 148 is a recording medium, and 150 is a reproduction signal processing circuit.

The operation of the circuit shown in FIG. 1 will be described. First, the circuit operation when watching a received digital broadcast will be described. The digital broadcast signal is transmitted after time-division multiplexing of packet data of a plurality of channels. When digital broadcasting is satellite broadcasting, a signal received by an antenna (not shown) is used. When digital broadcasting is cable TV, a signal from a cable (not shown) connected to each terminal is used.
The digital broadcast signal is input to an input terminal 1. The input signal from the input terminal 1 is subjected to demodulation processing and error correction processing during transmission by the tuner 10. When watching the received digital broadcast, the selection circuit 20 selects the output side of the tuner 10 by the control circuit 40, and the signal subjected to the demodulation processing and the error correction processing is input to the first information separation circuit 30. In the first information separation circuit 30,
According to the setting of the control circuit 40, necessary digital signals are separated and sent to the decoder 50. The decoder 50
The input digital compressed signal is decoded into a normal video signal and output to a receiver (not shown) via the output terminal 5.

Next, the circuit operation during recording will be described.
The input signal from the input terminal 1 of the digital broadcast signal is subjected to demodulation processing and error correction processing during transmission by the tuner 10. The signal subjected to the demodulation processing and the error correction processing is input to the second information separation circuit 35. In the second information separation circuit 35, information to be recorded is
Separate according to the setting of 0. Further, from the signal input to the second information separation circuit 35, information such as the type of packet data to be recorded is detected and sent to the control circuit 40. The control circuit 40 determines the recording mode based on the detected data, and sets the operation mode of the recording signal processing circuit 120 and the servo circuit 130. Second information separation circuit 3
The signal separated in 5 is input to the recording signal processing circuit 120. The recording signal processing circuit 120 extracts data for variable-speed reproduction, performs predetermined recording signal processing on the data for variable-speed reproduction and the data input from the second information separation circuit 35, and converts the recording signal. Generate. In the recording signal processing, signal processing such as addition of ID information, a subcode, and an error correction code is performed in accordance with the setting of a recording mode. Specific contents will be described later in detail. The recording signal processing circuit 1
The recording signal generated in 20 is recorded on the recording medium 148 via the magnetic heads 145a and 145b attached to the cylinder 140. In the embodiment of FIG. 1, by providing the first information separation circuit 30 and the second information separation circuit 35, it is possible to monitor simultaneously a channel different from the channel recorded at the time of recording. At the time of recording, the selection circuit 20 selects the output side of the tuner 10 by the control circuit 40, and the signal subjected to the demodulation processing and the error correction processing is input to the first information separation circuit 30. First
By setting different channels respectively in the information separation circuit 30 and the second information separation circuit 35, the channel for recording and the channel for output to the receiver can be separated,
Counter program recording is also possible. Of course, it is also possible to set the same channel in the first information separation circuit 30 and the second information separation circuit 35 and record while monitoring.

Next, the circuit operation during reproduction will be described.
At the time of reproduction, reproduction is first performed in an arbitrary reproduction mode, and the reproduction signal processing circuit 150 is reproduced via the magnetic heads 145a and 145b.
The ID information and the subcode added at the time of recording are detected from the reproduction data input to the CPU, and the reproduction mode is reset.
The reproduction signal processing circuit 150 performs predetermined reproduction signal processing such as synchronization detection and error correction processing in addition to the detection of the reproduction mode. Note that data for normal reproduction is processed during normal reproduction, and data for variable speed reproduction is processed during variable speed reproduction. The specific contents of the reproduction signal processing will be described later in detail. The signal processed by the reproduction signal processing circuit 150 is input to the selection circuit 20. At the time of reproduction, the selection circuit 20 selects the output side of the reproduction signal processing circuit 150 by the control circuit 40, and the signal subjected to the reproduction signal processing is input to the first information separation circuit 30. The first information separation circuit 30 separates necessary digital signals and sends them to the decoder 50 according to the setting of the control circuit 40. The decoder 50 decodes the input digital compressed signal into a normal video signal, and outputs the same to an image receiver (not shown) via the output terminal 5.

Next, digital compression will be briefly described with reference to FIG. As an example, in the present embodiment, MPEG2 (Moving
This is explained using Picture Experts Group 2). MPE
In G2, a compression process using the frame correlation of the video signal is performed. Generally, since video information has continuity, information between frames has high correlation. Therefore, the amount of data is compressed by combining intra-frame compression, which is performed using information on the completion of a frame, and inter-frame compression, which compresses only difference information using prediction from previous, subsequent, or previous or subsequent frame information. The intra-frame compressed data can be decoded from the data of the frame alone, but the inter-frame compressed data cannot be decoded without the previous, subsequent, or preceding and following frame data. The compressed data in frame units is called picture data. FIG. 2 (a)
The relationship between each frame of the digital compressed video signal is shown, 200 represents intra-frame compressed data, and 210 represents inter-frame compressed data. As shown in FIG. 2A, intra-frame compressed picture data is arranged every predetermined number of frames (every 15 frames in the example of FIG. 2), and the remaining frames are inter-frame compressed picture data. In the MPEG2 system, compressed data of the predetermined number of frames (15 frames in the example of FIG. 2),
That is, one sequence is composed of a predetermined number of picture data. FIG. 2B shows the data structure of a digital compressed signal of one sequence, where 220 is a sequence header indicating the head of each sequence, and 230 to 244 are picture headers indicating the head of each picture. The sequence header 220 is composed of a synchronization signal and information such as a transmission rate. The picture headers 230 to 244 are composed of a synchronization signal and identification information of intra-frame compression or inter-frame compression. The data amount of each picture is not always constant.

FIG. 3 is a diagram illustrating a digital broadcast signal. The digital compressed signal is divided into a packet format, and data for a plurality of channels and a channel information packet indicating program contents are time-division multiplexed to form a digital broadcast signal. FIG. 3A shows a configuration example of a packet. One packet is 188 as an example.
It is assumed that each packet is composed of a 4-byte packet header 300 and 184-byte packet data 310, for example. The packet header 300 includes information indicating the type of the packet and the like. FIG. 3B shows the configuration of the packet header 300. 320 is a synchronization byte indicating the beginning of the packet, 321
Indicates an error indicating the presence or absence of data error in the packet;
2 is a unit start flag indicating the start of the unit, 323
Is a priority indicating the importance of the packet, 324 is a PID (Packet ID) indicating the type of the packet, 325 is scramble control indicating the presence or absence of scrambling, 326 is an adaptation field control indicating the presence or absence of additional information, and 327. Is a cyclic counter that counts up in packet units. FIG. 3 (c) shows a digital broadcast signal in which the above packets are multiplexed, where V is a video information packet, A is an audio information packet,
P indicates a channel information packet such as a program content and a program guide, and the subscripts 1, 2, 3, and 4 indicate the multiplexed first, second, third, and fourth channels, respectively. FIG.
(C) shows an example in which information of four channels is time-division multiplexed, but the number of multiplexing is not limited to this, and varies depending on the capacity of the transmission path and the information amount of each channel. Also, the multiplexed signal is not limited to video information, and there is no problem even if it is other digital data. FIG. 3D shows a state where a packet related to the third channel is selected from the digital broadcast signal shown in FIG. 3C. When viewing the third channel, such a signal is output from the first information separation circuit 30 and decoded by the decoder 50.

Here, the general process of selecting a desired channel from a received digital broadcast signal and decoding it will be described with reference to the flowchart of FIG. First
The signal input to the information separation circuit 30 has a configuration in which the packets shown in FIG. 3C are multiplexed. First step 4
In step 01, the user inputs the organization channel of the program the user wants to watch from the operation terminal 45. The control circuit 40 sets the first information separation circuit 30 according to the input. here,
An organization channel is a name for collecting video, audio, and the like that constitute one program, and corresponds to a television channel in conventional analog broadcasting. In digital broadcasting, one frequency in which a plurality of programs are multiplexed is generally called a physical channel. Next, in step 402,
PAT (Program Association), which is one type of channel information packet included in the currently received digital broadcast signal
ation Table). PAT is a PSI (Program Spread Program) defined in the MPEG2 international standard.
ecific Information).
In step 403, the PAT received in step 402
To search for a desired organization channel. If there is a desired knitting channel, the process proceeds to step 407. If there is no desired knitting channel, the process proceeds to step 404, and P
A channel information packet NIT which is a type of SI and describes the relationship between the organization channel and the physical channel.
(Network Information Table) is received, a physical channel including a desired organization channel is obtained, and in the next step 405, the process shifts to the physical channel obtained in step 404. Physical channel migration is
In an actual circuit, the control is performed by setting a frequency to be selected to the tuner 10 from the control circuit 40 shown in FIG.
Thereafter, in step 406, the PAT of the digital broadcast signal on the physical channel after the shift is received. Upon receiving the PAT, in step 407, the PID (Packet I,
Channel information packet PMT (Pr
The PID of the PMT is obtained from the PAT, and the PMT having the PID is received. However, PMT is PS
I is one of the tables of I, and PID is a packet identifier included in the header of the packet. Since the PMT describes PIDs of video, audio, etc., constituting each composition channel included in the digital broadcast signal being received,
In step 408, the PID of the video and audio of the desired program is obtained. Then, the obtained PID is used in step 4
In step 09, the information is set in the first information separation circuit 30, and the desired video and audio data are separated and input to the decoder 50 for decoding.

Next, the format of the recording signal generated by the recording signal processing circuit 120 will be described.

FIG. 5A shows a recording pattern of one track on the recording medium 148. 530 is a subcode recording area for recording subcodes such as program information, and 570 is a data recording area for recording digital compressed video signals.
20 and 560 are preambles of respective recording areas,
540 and 580 are postambles of the respective recording areas, 550 is a gap between the respective recording areas, 51
0 and 590 are margin areas. By providing a postamble, a preamble, and a gap in each recording area in this way, it is possible to perform dubbing on each area independently. Of course, the data recording area 57
In 0, a digital signal other than the digital compressed video signal may be recorded.

FIG. 5B shows a sub code recording area 530.
Is a block configuration. In the block of the subcode recording area, for example, the synchronization signal 531 has 2 bytes, and the ID information 5
32 is composed of 3 bytes, the subcode data 533 is composed of 19 bytes, the parity 534 is composed of 4 bytes, and one block is composed of 28 bytes. The parity 5
34 adds a 4-byte parity to 19 bytes of the subcode data 533. For example, a Reed-Solomon code may be used as the error correction code. It is assumed that the subcode recording area 530 includes 16 blocks described above. Thus, by forming a block with a relatively short number of bytes, it is possible to improve the subcode detection rate at the time of variable speed reproduction or the like. Also, by multiplexing and recording the same contents in the 16 blocks, it is possible to further improve the subcode detection rate.

FIG. 5C shows a block configuration of the data recording area 570. 620 is a synchronization signal, 630 is ID information, 640 is a block header, 645 is data, 650
Is a parity (C1 parity) for error detection and correction. For example, the synchronization signal 620 has 2 bytes and the ID information 63
0 is 3 bytes, block header 640 is 3 bytes, data 645 is 96 bytes, parity 650 is 8 bytes, and 1 block is 112 bytes. The parity 650 adds an 8-byte parity to 99 bytes obtained by combining the block header 640 and the data 645. For example, a Reed-Solomon code may be used as the error correction code. Data recording area 57
0 is composed of 336 blocks described above.

FIG. 6A shows the structure of the ID information 630. 631 is a sequence address, 632 is a track address, 633 is a block address in one track, 6
Reference numeral 35 denotes a parity for detecting an error in the group number 631, the track address 632, and the block address 633. For example, the sequence address 631 has 4 bits, the track address 632 has 3 bits, the block address 633 has 9 bits, and the parity 635 has 8 bits. The block address 633 is an address for identifying a block in each recording area. For example, in the data recording area 670, it is 0 to 335. The track address 632 is an address for identifying a track.
By setting to 2, six tracks can be identified. The sequence address 631 is changed, for example, in units of six tracks identified by the track address 632, and
By setting to 15, 96 tracks can be identified.

The block header 640 is made up of information on blocks, and records, for example, information indicating data for variable speed reproduction, information on the type of recording signal, recording time, and the like. FIG. 6B shows a block header 640.
It is a structure of. The block header 640 includes format information 641, block information 642, and additional information 643. The format information 641 is information on a recording format, and for example, one information is composed of three bytes of six blocks. By multiplex-recording this information a plurality of times, the detection capability at the time of reproduction is improved. Here, the presence / absence and type of the variable speed reproduction data are recorded, and the data is identified at the time of reproduction, so that it is possible to easily cope with the variable speed reproduction. The block information 642 is information for identifying the type of data recorded in the data 645. Here, the presence / absence and type of the variable speed reproduction data are recorded, and the data is identified at the time of reproduction, so that it is possible to easily cope with the variable speed reproduction. For example, if 2 bits in the block information 642 are used, 0 represents normal reproduction data, 1 represents dummy data, 2 represents variable speed reproduction data, and 3 represents a reserve. It is possible to determine the type of the reproduction data. The additional information 643 is configured by, for example, forming one piece of information with 6 bytes of 6 blocks, the first 1 byte being an item code indicating the type of information, and the remaining 5 bytes being data.
Various types of data can be recorded. For example, information such as the recording time and the type of the recording signal are recorded. Further, detailed information on the variable speed reproduction data may be recorded here.

FIG. 7 shows an example of a block configuration when a digital compressed signal transmitted in a packet format of 188 bytes is recorded in an area of data 645. In this case, 4
192 bytes by adding byte time information 660,
One packet is recorded in two blocks. Time information 660
Indicates information on the time at which the packet was transmitted. The packet transmission time or the packet interval is counted by the reference clock, and the count value is recorded together with the packet data. At the time of reproduction, the packet interval is set based on the information, and when the packet is transmitted. Can be output in the same form as.

FIG. 8 shows a layout of variable speed reproduction data. Basically, a predetermined number of blocks are recorded at a predetermined position on a track. FIG. 8A shows a configuration of a data recording area 570 of one track.
Reference numeral 2 denotes a recording area for variable speed reproduction data. FIG. 8 (a)
In the above example, one track is provided with four variable-speed reproduction data recording areas, but the number is not limited to four. Each recording area is composed of three blocks.
It is not limited to three blocks. The variable speed reproduction data extracted by the recording signal processing circuit 120 is sequentially recorded in the variable speed reproduction data recording area. FIG.
(B) is a diagram showing a recording pattern on a recording medium. In FIG. 8B, reference numeral 820 denotes 801 to 81 in FIG.
This is a recording area of variable speed reproduction data indicated by 2. Regarding data for variable speed reproduction, the same data is multiplex-recorded over a predetermined track. This is because the trajectory of the magnetic head during variable speed reproduction is different from that during normal reproduction and scans over a plurality of tracks (indicated by the dotted line in FIG. 8B). FIG. 8B shows an example in which the same data is multiplex-recorded in units of 16 tracks, but the number of multiplex tracks is not limited to this, and is determined by the corresponding variable speed reproduction speed. Thus, no matter how the magnetic head scans the recording medium during variable speed reproduction, all data for variable speed reproduction can be read.

Next, signal processing at the time of recording will be described in detail. First, the user inputs a program to be recorded from the operation terminal 45. The control circuit 40 sets the second information separation circuit 35 according to the input, and sends necessary information to the tuner 1.
Separate from the digital broadcast signal input from 0. The operation of the second information separation circuit 35 at this time is basically the same as the operation of the first information separation circuit 30 described with reference to FIG. Note that the contents of the channel information packet can be rewritten according to the recording signal for convenience during playback,
A new channel information packet may be generated. Second
The output of the information separation circuit 35 is
Sent to

FIG. 9 is a diagram showing the configuration of the recording signal processing circuit 120. 9, reference numeral 900 denotes an input terminal for data processed by the second information separation circuit 35; 905, an input / output terminal for exchanging data with the control circuit 40;
0 is a time information generation circuit, 915 is an information extraction circuit for extracting information for variable speed reproduction, 950 is a memory for normal reproduction data, 955 is a memory for variable speed reproduction data, and 920 controls the memories 950 and 955 and the like. Recording system control circuit, 92
5 is a selection circuit, 930 is a recording information addition circuit for adding ID information, block information, etc., 940 is an error correction code addition circuit, and 945 is an output terminal for the generated recording signal. Second
The packet input from the information separating circuit 35 of the above through the input terminal 900 is sent to the time information generating circuit 910, and the time information 660 to which each packet is transmitted is added. The packet to which the time information 660 has been added is written to the normal reproduction data memory 950 in accordance with the control signal of the recording system control circuit 920 and sent to the information extraction circuit 915. The information extraction circuit 915 extracts information for variable speed reproduction. As described above, the digital compressed signal is composed of intra-frame compressed data and inter-frame compressed data. As data for variable speed playback,
The intra-frame compressed data is used because it is necessary to be able to decode with the compressed data of a single frame. The information extraction circuit 915 determines and extracts intra-frame compressed data packets from the input compressed data using the sequence header and picture header data described in FIG. 2 and extracts channel information packets. Of course, the determination of the packet of the intra-frame compressed data is not limited to the sequence header and the picture header, and any data that can be determined may be used. Note that not all intra-frame compressed data is extracted for variable-speed playback. Since the picture is multiplex-recorded in the recording area of the variable-speed playback data with the picture completed, the intra-frame compressed data is thinned out at appropriate intervals. The extracted packet is written to a predetermined location in the variable speed reproduction data memory 955 according to a control signal from the recording system control circuit 920. Further, the recording system control circuit 920 controls reading of normal reproduction data and variable speed reproduction data from the memory 950 and the memory 955 in a predetermined order according to the recording format. Data read from the memory 950 and the memory 955 is supplied to the selection circuit 925.
And necessary data is appropriately selected in accordance with the recording format. The selected data is added with ID information, block information, and the like by a recording information adding circuit 930.

Here, in the present invention, a discontinuity flag indicating that the channel information, data and the like are discontinuous is added by the recording information adding circuit 930 as an example. The discontinuity is at the start of recording, at the end of recording, when a program is switched during recording, or the like. The discontinuity flag is, for example, the additional information 64
3, and multiplex recording is performed a plurality of times during a predetermined period. By performing multiplex recording a plurality of times for a predetermined period in this manner, even if a tape is damaged or a magnetic head is clogged during reproduction, the discontinuity flag can be reliably detected. Also, by adding the discontinuity flag to both the normal reproduction data and the variable speed reproduction data, the discontinuity flag can be used for normal reproduction and variable speed reproduction. The discontinuity flag is not limited to the additional information 643, and if it can be detected at the time of reproduction, there is no problem in recording the recording signal anywhere and in any form. For example, there is no problem even if the discontinuity flag is recorded in the subcode recording area. The method of using the discontinuity flag will be described when the reproduction signal processing is described. The signal to which the recording information has been added is output from an output terminal 945 after adding an error correction code by an error correction code adding circuit 940, and is recorded on a recording medium via a magnetic head.

Next, signal processing during reproduction will be described in detail. At the time of reproduction, a signal reproduced first in an arbitrary reproduction mode and reproduced from the recording medium 148 by the magnetic heads 145a and 145b is input to the reproduction signal processing circuit 150.

FIG. 10 is a diagram showing a configuration of the reproduction signal processing circuit 150. 10, reference numeral 1000 denotes a reproduction signal input terminal; 1010, an error correction circuit; 1015, an additional information detection circuit for detecting information added during recording;
Reference numeral 20 denotes a packet selection circuit; 1025, an information detection circuit for detecting a break in a picture from variable speed reproduction data;
Numeral 30 is a reproduction system control circuit, 1035 is an input / output terminal for exchanging data with the control circuit 40, 1040 is a normal reproduction data memory, 1045 is a variable speed reproduction data memory,
1050 is a selection circuit, 1060 is an output control circuit, 106
Reference numeral 5 denotes an output terminal of a signal subjected to reproduction signal processing, 1070 denotes a discontinuity flag detection circuit, and 1075 denotes a discontinuity flag output terminal.

First, a reproduction signal processing circuit 15 during normal reproduction
The circuit operation of 0 will be described. The reproduction signal input from the input terminal 1000 is first subjected to error correction by an error correction circuit 1010 using an error correction code added at the time of recording.
The error-corrected data is input to the additional information detection circuit 1015, which detects the ID information, subcode, and the like added during recording, and resets the reproduction mode. The error-corrected data is written to a predetermined location on the normal reproduction data memory 1040 in accordance with a control signal of the reproduction system control circuit 1030. The selection circuit 1050 selects the output of the normal reproduction data memory 1040 during normal reproduction. The data read from the normal reproduction data memory 1040 is input to the output control circuit 1060 and the discontinuity flag detection circuit 1070 via the selection circuit 1050. The output control circuit 1060 controls the output timing of the packet, stops the output, and the like. First, the type of reproduction data is determined from the block information 642 added at the time of recording, and only the data for normal reproduction is selected.
The packet is output from 65. It should be noted that the data whose error cannot be corrected by the error correction circuit 1010 is not output. On the other hand, when the discontinuity flag detection circuit 1070 detects the discontinuity flag added at the time of recording, the information is sent to the control circuit 40 via the discontinuity flag output terminal 1075. The usage of the discontinuity flag is the same during variable speed reproduction, and will be described later. The packet data processed by the reproduction signal processing circuit 150 is input to the selection circuit 20. When viewing the reproduction signal, the selection circuit 20 selects the output of the reproduction signal processing circuit 150. The packet data of the selected reproduction signal is separated into video and audio packets in the first information separation circuit 30 based on the set channel information. Each of the separated packets is decoded by the decoder 50 and output to the receiver.

Next, a reproduction signal processing circuit 15 for variable speed reproduction
The circuit operation of 0 will be described. The reproduction signal input from the input terminal 1000 is first subjected to error correction by an error correction circuit 1010 using an error correction code added at the time of recording.
The error-corrected data is supplied to a packet selection circuit 1020.
The type of reproduction data is determined from the block information 642 added at the time of recording, and only data for variable speed reproduction is selected. The selected variable speed reproduction data is written to a predetermined location on the variable speed reproduction data memory 1040 in accordance with the control signal of the reproduction system control circuit 1030. At the same time, the information detection circuit 1025 detects a break in each picture by using information such as a sequence header and a picture header in the selected data for variable speed reproduction, and sends it to the reproduction system control circuit 1030. At the time of variable speed reproduction, decoding is started basically when one piece of picture data is collected. Therefore, when the information detection circuit 1025 detects a break in a picture, reading of data stored in the variable speed data memory 1045 is started. The data read from the variable speed data memory 1045 passes through the selection circuit 1050 and the output control circuit 1060
And to the discontinuity flag detection circuit 1070. The selection circuit 1050 switches so as to select the output of the variable speed reproduction data memory 1045 during variable speed reproduction. The output control circuit 1060 reproduces data on a time axis different from the original time axis during variable speed reproduction, so that output control different from that during normal reproduction is performed. At the time of variable speed reproduction, output control based on time information is performed for each picture. That is, the first packet of each picture is output from the time when the picture data is prepared, and its time information is used as the initial value of the picture, and the subsequent packets are output at intervals according to the time information with respect to the initial value. . Since the interval between pictures is variable-speed reproduction, it cannot be different from time information. Alternatively, the packet output interval during variable speed reproduction may be output at an appropriate interval irrespective of the added time information. Note that the error correction circuit 101
Data whose error could not be corrected with 0 is not output. The packet data output-controlled by the output control circuit 1060 is sent to the selection circuit 20 via the output terminal 1065. On the other hand, when the discontinuity flag detection circuit 1070 detects the discontinuity flag added at the time of recording, the information is sent to the control circuit 40 via the discontinuity flag output terminal 1075. The usage of the discontinuity flag will be described later. In the present embodiment, the memories for the normal reproduction data and the variable speed reproduction data are separately provided, but one memory may be used to reduce the number of parts.

The packet data processed by the reproduction signal processing circuit 150 is input to the selection circuit 20. When the reproduction signal is to be viewed, the selection circuit 20 controls the reproduction signal processing circuit 1
Select 50 outputs. The packet data of the selected reproduction signal is separated into video and audio packets in the first information separation circuit 30 based on the set channel information. Each of the separated packets is supplied to the decoder 50.
And output to the receiver.

Next, the usage of the discontinuity flag will be described. The discontinuity flag detected by the discontinuity flag detection circuit 1070 is input to the control circuit 40. The discontinuous flag is basically used in the same manner in normal reproduction and variable speed reproduction. As described above, the discontinuity flag is added at the start of recording, at the end of recording, or when a program is switched during recording. In such a case, the switching basically changes the packet identifier PID and the like of the packet. Therefore, at the time of the above-mentioned discontinuous portion at the time of reproduction, the packet cannot be detected because the identifiers PID and the like of the subsequent packets are different. Therefore, when the control circuit 40 receives the discontinuity flag,
The channel information packet is searched again from the packet of the reproduction signal input to the first information separation circuit 30 to obtain necessary information such as a packet identifier, and the first information separation circuit 30 is reset. The first information separation circuit 30 separates a necessary packet according to the reset channel information. Thus, even when several different programs are recorded on the same recording medium, a necessary channel information packet is automatically searched again at a discontinuous point at the time of reproduction, so that no problem occurs.

After the necessary video and audio packets are separated by the first information separation circuit 30 having been set as described above, they are decoded by the decoder 50 and output to the receiver.

In the above embodiment, an example is shown in which the discontinuity flag is generated by the recording information adding circuit 930 and recorded in the additional information 643, but the present invention is not limited to this. In the second embodiment, a discontinuity flag packet is used as one of the channel information packets in the second information separation circuit 35.
To be newly generated and recorded. For example, when a program is switched, at the start of recording, or at the end of recording, the data recorded so far and the channel information are basically different. Therefore, the second information separation circuit 35 separates the data to be recorded according to the setting of the control circuit 40, multiplexes the discontinuous flag packet with the separated data, and sends the data to the recording signal processing circuit 120. The operation of the second information separation circuit 35 will be described with reference to FIG. A digital compressed signal is divided into packet formats, and data for a plurality of channels and a channel information packet indicating program contents are time-division multiplexed to form a digital broadcast signal. FIG. 11A shows a digital broadcast signal in which packets are multiplexed.
Indicates a video information packet, A indicates an audio information packet, P indicates a channel information packet such as a program content or a program table, and the subscripts 1, 2, 3, and 4 are multiplexed first, second, third, and multiplex, respectively. The fourth channel is shown. FIG. 11B
Shows the output of the second information separation circuit 35 when recording the third channel from the digital broadcast signal shown in FIG. In the present embodiment, a third channel-related packet to be recorded is selected, and for example, at the start of recording, packets 1300 to 1302 (P3
The discontinuous flag packet shown in f) is multiplexed and output, and sent to the recording signal processing circuit 120. Here, the discontinuous flag packets are multiplexed and recorded for a predetermined period. This makes it possible to reliably detect the discontinuity flag packet even if the tape is damaged or the magnetic head is clogged during reproduction. The recording signal processing circuit 120 generates a recording signal by adding the above-described recording information and error correction code. Of course, in addition to the discontinuity flag packet, a discontinuity flag may be recorded in the additional information 643 to improve the flag detection rate. Similarly to the discontinuity flag, the discontinuity flag packet records both data for normal reproduction and variable speed reproduction. As a result, the discontinuous flag packet can be used during normal reproduction and variable speed reproduction. Playback signal processing circuit 1 for discontinuous flag packet
When the discontinuity flag detection circuit 1070 detects the channel information, the channel information is basically searched again. Since the circuit operation of the re-search processing is the same as that of the first embodiment, the following description of the circuit operation is omitted. Further, as in the first embodiment, the discontinuity flag packet is detected by the reproduction signal processing circuit 150.
The present invention is not limited to this. Regardless of the discontinuity flag detection circuit, there is no problem even if the discontinuity flag detection circuit is provided in the first information separation circuit, for example.

Further, the two pieces of discontinuous information are newly added to the recording signal, but the present invention is not limited to this method. That is, it is only necessary to detect discontinuity of channel information. For example, a channel information packet included in the digital broadcast signal may be used. The first information separation circuit 3
0, if PAT and PMT, which is one of the channel information packets detected from the input signal, are constantly compared with the currently used PAT and PMT, it is possible to detect the change point of the channel information. It is. Thereafter, signal processing is performed based on the new channel information. Subsequent signal processing is the same as in the first embodiment, and a description of the following circuit operation will be omitted.

The discontinuous information may be used in combination. Thereby, discontinuity of channel information can be detected more reliably.

In the above-described embodiments, the digital information recording / reproducing system has been described with respect to an example in which the digital broadcast receiving portion and the recording / reproducing portion are integrated. They may be configured separately. FIG. 12 shows a digital transmitting / receiving apparatus 170 and a digital signal recording / reproducing apparatus 1.
It is a block diagram showing an example of a circuit configuration in the case of configuring with 75. Basically, the same circuit as the circuit shown in FIG. 1 has the same circuit operation, and the description is omitted. Since they are separate, the control circuit 16 of the digital signal recording / reproducing device 175
0 and the operation terminal 165 are newly added. Thereby, the operation of the digital signal recording / reproducing device 175, for example, recording, reproduction, stop, search, recording reservation, and the like can be set. Here, the connection between the digital broadcast receiving device 170 and the digital signal recording / reproducing device 175 is basically made by a digital signal obtained by separating the signal to be recorded by the second information separating circuit 35 (FIG. 3D, FIG. 11B). ), A reproduced digital signal and a control signal for connecting the control circuit 40 and the control circuit 160. A detection signal of a discontinuous flag used in the present invention, information indicating a reproduction direction of variable speed reproduction, and the like are input and output as the control signal. Also,
By connecting the control circuit of each device, the digital broadcast receiving device 170 can be connected to the digital signal recording / reproducing device 17.
5 can be operated, for example, to set a reserved recording, or conversely, the digital signal recording / reproducing device 175 can operate the digital broadcast receiving device 170. In this embodiment, the recording signal and the reproduction signal are separately connected, but may be connected as one input / output signal. Since the signal processing is basically the same, the description of the operation is omitted.

FIG. 13 is a diagram showing another example of the configuration when the digital broadcast receiving device and the digital signal recording / reproducing device are separately configured. In FIG. 13, reference numeral 180 denotes a digital broadcast receiving device, 185 denotes a digital signal recording / reproducing device, 160 denotes a control circuit of the digital signal recording / reproducing device 180, and 165 denotes an operation terminal of the digital signal recording / reproducing device 180. In the example of FIG. 13, the digital signal recording / reproducing device 185 includes a second information separating circuit 35. Therefore, the digital broadcast receiving apparatus 1
What is input from 80 to the digital signal recording / reproducing device 185 is an original digital broadcast signal in which signals of a plurality of channels shown in FIGS. 3C and 11A are multiplexed. Further, a reproduction digital signal and a control signal for connecting the control circuit 40 and the control circuit 160 are connected.
A detection signal of a discontinuous flag used in the present invention, information indicating a reproduction direction of variable speed reproduction, and the like are input and output as the control signal. In addition, by connecting the control circuit of each device, the digital broadcast receiving device 180 can operate the digital signal recording / reproducing device 185, for example, to set a reserved recording, or vice versa.
It is possible to operate the digital broadcast receiving device 180 from. In this embodiment, the recording signal and the reproduction signal are separately connected, but may be connected as one input / output signal. Since the signal processing does not change at all, the description is omitted.

As described above, according to the present invention, it is possible to realize a digital information recording / reproducing apparatus capable of recording and reproducing digital broadcasts and capable of performing variable speed reproduction with ease of use.

Although the present embodiment has been described based on MPEG2 as a digital compression method, the present invention is not limited to this compression method.

Although only the digital recording / reproducing circuit configuration is shown in the embodiment, the digital information recording / reproducing apparatus which is compatible with the conventional analog recording / reproducing apparatus by installing the conventional analog recording / reproducing circuit is also provided. Is also feasible.

[0041]

According to the present invention, in addition to the digital compression signal for variable speed reproduction, information indicating discontinuity of channel information at the start of recording or at the point where channel information changes is added to a predetermined recording area on a recording medium. The number of tracks is multiplex-recorded. At the time of normal reproduction and at the time of variable speed reproduction, the digital broadcast receiver re-searches the channel information as appropriate based on the information indicating the discontinuity, and decodes the digital compressed signal according to the result.

As described above, in a digital information recording / reproducing system for receiving and receiving a digital broadcast in which digital compressed signals of a plurality of channels are multiplexed, and recording and reproducing the received signal as a digital signal, a user-friendly normal reproduction and variable speed reproduction Can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a digital compression signal.

FIG. 3 is a diagram illustrating a configuration of a digital broadcast signal.

FIG. 4 is a flowchart showing a flow of signal processing of a digital broadcast receiving unit.

FIG. 5 is a diagram illustrating a recording format of one track.

FIG. 6 is a diagram illustrating constituent elements of a block in a data recording area.

FIG. 7 is a diagram illustrating a block configuration when a 188-byte packet is recorded.

FIG. 8 is a diagram illustrating the arrangement of variable speed reproduction data.

FIG. 9 is a configuration example of a recording signal processing circuit 120;

FIG. 10 is a configuration example of a reproduction signal processing circuit 150;

FIG. 11 is a diagram illustrating an example of insertion of a packet indicating discontinuity.

FIG. 12 is a diagram illustrating a configuration example of a digital broadcast receiving device and a digital signal recording / reproducing device that constitute a digital information recording / reproducing system.

FIG. 13 is a diagram illustrating another configuration example of a digital broadcast receiving device and a digital signal recording / reproducing device that constitute a digital information recording / reproducing system.

[Explanation of symbols]

1: Digital broadcast input terminal, 10: Tuner, 20
... Selection circuit, 30, 35 information separation circuit, 40 control circuit, 45 operating terminal, 50 decoder, 120 recording signal processing circuit, 150 reproduction signal processing circuit, 200 intra-frame compressed data, 210 inter Frame compressed data, 300 packet header, 310 packet data, 530 subcode recording area, 570 data recording area, 915 information extraction circuit, 920 recording control circuit, 1010 error correction circuit, 1020 packet selection Circuit, 1030 ... Reproduction system control circuit, 1070 ... Discontinuous flag detection circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeo Okochi 1410 Inada, Hitachinaka-shi, Ibaraki Pref. Hitachi, Ltd. Visual Information Media Division

Claims (31)

[Claims] 1. A digital compressed video comprising a first compressed digital signal comprising picture data compressed only by data in a frame and a second compressed digital signal comprising picture data compressed using data between frames. A digital information recording method for recording, on a recording medium, a digital signal in which signal data and channel information including information capable of identifying each channel of the digital compressed video signal are time-division multiplexed in a packet format of a predetermined byte. The digital information recording method according to claim 1, wherein information indicating discontinuity of the channel information is recorded in addition to the digital signal. 2. The digital information according to claim 1, wherein the information indicating the discontinuity of the channel information is recorded at least at the start of recording, at the end of recording, and each time the channel information changes. Recording method. 3. The digital information recording method according to claim 1, wherein a plurality of pieces of information indicating the discontinuity of the channel information are recorded in a predetermined period. 4. The information indicating discontinuity of the channel information is multiplexed with the digital signal and recorded as channel information in a packet format.
Digital information recording method described. 5. A digital compressed video signal composed of a first compressed digital signal composed of picture data compressed only with data in a frame and a second compressed digital signal composed of picture data compressed using data between frames. And digital information for recording and reproducing on a recording medium a digital signal obtained by time-divisionally multiplexing data of the digital compressed video signal and channel information including information capable of identifying each channel of the digital compressed video signal on a recording medium. In the recording / reproducing method, information indicating discontinuity of the channel information is recorded in addition to the digital signal at the time of recording, and when the information indicating the recorded discontinuity is detected at the time of reproduction, the channel information is searched again. Processing the compressed digital signal based on the obtained channel information. Digital information recording and reproducing method characterized. 6. The digital information according to claim 5, wherein the information indicating the discontinuity of the channel information is recorded at least at the start of recording, at the end of recording, and each time the channel information changes. Recording and playback method. 7. The digital information recording / reproducing method according to claim 5, wherein a plurality of pieces of information indicating the discontinuity of the channel information are recorded in a predetermined period. 8. The information indicating discontinuity of the channel information is multiplexed with the digital signal and recorded as packet-type channel information.
The digital information recording and reproducing method described in the above. 9. A digital compressed video signal composed of a first compressed digital signal composed of picture data compressed only with data in a frame and a second compressed digital signal composed of picture data compressed using data between frames. And a channel signal including information capable of identifying each channel of the digital compressed video signal in a time-division multiplexed packet format of a predetermined byte, and a packet including at least the first compressed digital signal. A digital signal recording method for recording a third signal on a recording medium, wherein information indicating discontinuity of the channel information is recorded in addition to the digital signal and the third signal. Digital information recording method. 10. The digital information according to claim 9, wherein the information indicating the discontinuity of the channel information is recorded at least at the start of recording, at the end of recording, and each time the channel information changes. Recording method. 11. The digital information recording method according to claim 9, wherein a plurality of pieces of information indicating the discontinuity of the channel information are recorded in a predetermined period. 12. The digital information according to claim 9, wherein the information indicating the discontinuity of the channel information is multiplexed with the digital signal and the third signal and recorded as packet-type channel information. Recording method. 13. The digital information recording method according to claim 9, wherein said third signal includes a packet of said channel information. 14. A digital compressed video signal comprising a first compressed digital signal comprising picture data compressed only by data within a frame, and a second compressed digital signal comprising picture data compressed using data between frames. And a channel signal including information capable of identifying each channel of the digital compressed video signal in a time-division multiplexed packet format of a predetermined byte, and a packet including at least the first compressed digital signal. A digital information recording / reproducing method for recording and reproducing a third signal on a recording medium and recording information indicating discontinuity of channel information in addition to the digital signal and the third signal at the time of recording. During normal playback and variable speed playback, the information indicating the recorded discontinuity is detected. Was the case, then search the channel information, the digital information recording and reproducing method characterized by processing said compressed digital signal based on the obtained channel information. 15. The digital information according to claim 14, wherein the information indicating the discontinuity of the channel information is recorded at least at the start of recording, at the end of recording, and each time the channel information changes. Recording and playback method. 16. The digital information recording / reproducing method according to claim 14, wherein a plurality of pieces of information indicating the discontinuity of the channel information are recorded in a predetermined period. 17. The digital information according to claim 14, wherein the information indicating the discontinuity of the channel information is multiplexed with the digital signal and the third signal and recorded as packet-type channel information. Recording and playback method. 18. The digital information recording / reproducing method according to claim 14, wherein said third signal includes a packet of said channel information. 19. A digital compression system comprising a first compressed digital signal composed of picture data compressed only with data in a frame and a second compressed digital signal composed of picture data compressed using data between frames. A signal generation device that selects a predetermined signal from a digital signal in which a video signal and channel information including information capable of identifying each channel are time-division multiplexed in a packet format of a predetermined byte and generates a predetermined signal. First digital signal input means for inputting the digital signal; setting means for setting an arbitrary number of channels from the digital signal; and a channel set by the setting means based on the digital signal input from the input means. Comprising the first and second compressed digital signals of First information separating means for separating compressed video signal and channel information, discontinuous information output means for outputting information indicating discontinuity of channel information, signal separated by the first information separating means, and the discontinuity A first digital signal output means for outputting information indicating discontinuity of the channel information output by the information output means, and a first digital signal output means. 20. The discontinuity information output means for outputting information indicating discontinuity of channel information outputs information indicating discontinuity of channel information at least each time the channel information changes. 20. The signal generator according to claim 19. 21. A discontinuous information output means for outputting information indicating discontinuity of channel information outputs a plurality of information indicating discontinuity of channel information in a predetermined period. The signal generation device according to any one of the preceding claims. 22. A discontinuous information output means for outputting information indicating discontinuity of channel information generates information indicating discontinuity of the channel information as one of channel information in a packet format. The signal generating device according to claim 19. 23. Digital compression comprising a first compressed digital signal consisting of picture data compressed only with data within a frame and a second compressed digital signal consisting of picture data compressed using data between frames. A signal generation device that selects a predetermined signal from a digital signal in which a video signal and channel information including information capable of identifying each channel are time-division multiplexed in a packet format of a predetermined byte and generates a predetermined signal. An input unit for inputting the digital signal; a setting unit for setting an arbitrary number of channels from the digital signal; a digital signal input from the input unit; A digital compressed video signal composed of a second compressed digital signal and a channel; First information separating means for separating the channel information, and a third packet-formatted signal obtained by extracting at least predetermined information consisting of the first compressed digital signal from the digital compressed video signal separated by the first information separating means. A data extraction unit for generating a signal; a discontinuity information output unit for outputting information indicating discontinuity of channel information; a signal separated by the first information separation unit, a third signal, and a discontinuity of the channel information. And a first digital signal output means for outputting information indicating continuity. 24. The discontinuity information output means for outputting information indicating discontinuity of channel information outputs information indicating discontinuity of channel information at least every time the channel information changes. 23. The signal generator according to claim 23. 25. A discontinuous information output means for outputting information indicating discontinuity of channel information outputs a plurality of information indicating discontinuity of channel information in a predetermined period. The signal generation device according to any one of the preceding claims. 26. The discontinuity information output means for outputting information indicating discontinuity of channel information generates information indicating discontinuity of the channel information as one of channel information in packet format. The signal generator according to claim 23. 27. The signal generating apparatus according to claim 23, wherein said third signal includes a packet of said channel information. 28. Digital compression comprising a first compressed digital signal composed of picture data compressed only with data within a frame and a second compressed digital signal composed of picture data compressed using data between frames. A decoding device for inputting a digital signal in which a video signal and channel information comprising information capable of identifying each channel of the digital compressed video signal in a predetermined number of packet formats and decoding the compressed digital signal , A second digital signal input means for inputting the digital signal, a discontinuity information detecting means for detecting information indicating that the channel information is discontinuous, and a required compressed digital signal based on predetermined channel information. A second information separating unit for separating, and the second information separating unit Decoding means for decoding the separated compressed digital signal; and when the discontinuity information detecting means detects information indicating that the channel information is discontinuous, the second information separating means detects the channel information. Wherein the decoding means separates a necessary compressed digital signal based on the information obtained by the re-searching, and decodes the compressed digital signal by the decoding means. 29. Digital compression comprising a first compressed digital signal consisting of picture data compressed using only data within a frame and a second compressed digital signal consisting of picture data compressed using data between frames. A decoding device for inputting a digital signal in which a video signal and channel information comprising information capable of identifying each channel of the digital compressed video signal in a predetermined number of packet formats and decoding the compressed digital signal A second digital signal input means for inputting the digital signal; a discontinuity information input means for inputting information indicating that channel information is discontinuous; and a required compressed digital signal based on predetermined channel information. A second information separating unit for separating, and the second information separating unit Decoding means for decoding the separated compressed digital signal; and when information indicating that the channel information is discontinuous is input from the discontinuous information input means, the second information separating means A decoding apparatus wherein information is searched again, a required compressed digital signal is separated based on the information obtained by the search again, and the decoding means decodes the compressed digital signal. 30. A digital information recording method for recording a digital signal on a recording medium, comprising, in addition to the digital signal, recording information indicating discontinuity of the digital signal at least at the start of recording and at the end of recording. Characterized digital information recording method. 31. A digital information recording method according to claim 30, wherein a plurality of pieces of information indicating the discontinuity of the digital signal are recorded in a predetermined period.