JP2003284002A - Digital data recording device and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that much time is required for decoding because an operation of a decoder becomes unstable in the case that the time information is discontinuous at the time of skip reproducing for MPEG data of packet form, moreover since the decode cannot be performed until PAT (program association table) and PMT (program map table) are detected, thereby requiring much time for picture display. <P>SOLUTION: This device is provided with a time information converting means 806 for converting time information in reproduced data. The device controls so that the increasing amount of time information per unit of time is kept constant. The device is provided a packet generating means 807 and inserts PAT (program association table), PMT (program map table), and PCR (program clock reference). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording or reproducing apparatus for recording or reproducing video / audio data, and more particularly, recording compressed digital data in packet format on an optical disk, a hard disk, a semiconductor memory or the like. The present invention relates to an apparatus for recording or reproducing on a medium.

[0002]

2. Description of the Related Art A technique for reducing the amount of video and audio data by a digital data compression technique is widely used.
MPEG (Moving Picture Experts Gro)
There is a compression method called up) method. The use of digital data compression technology has made it possible to broadcast and store high-quality images.

As a recording / reproducing apparatus for recording / reproducing such digital data, various recording / reproducing apparatuses such as a digital VTR using a magnetic tape, an optical disk, a semiconductor memory and the like can be considered. In particular, in a recording / reproducing device using an optical disk or a semiconductor memory, random access to the medium is possible,
It is easy to call a desired scene and perform high-speed search, and it is easy to use.

By the way, in the MPEG system, data compression is performed by utilizing the correlation between the images before and after. In general, data compression is often performed on a group of about 15 images. The group of this data is GOP (Gr
oup Of Pictures). When performing random access, if the data is reproduced from the beginning of the GOP, the data can be restored from the beginning of the reproduced data.
The time required for decoding can be shortened as compared with the case of reproducing data from the middle of GOP.

In order to realize this, MPEG is recorded on the recording medium.
When recording system data, the positions where GOPs are recorded are registered in advance as a list. When random access occurs during reproduction, control is performed so that reproduction is started from the GOP head position registered in this GOP position list, and the time required for decoding after random access is shortened. An image reproducing apparatus that makes a list of GOP positions and enables reproduction from the GOP head position is disclosed in Japanese Patent Application Laid-Open No. 200-200200.
No. 0-125259.

[0006]

However, in the above-described data output method, it is often impossible to immediately decode the data after the data is reproduced. This is because, when the decoder decodes the data, the PAT (Program Association Tabl) for determining the PID (packet identification number) of the video packet in addition to the video packet.
Information packets such as e) and PMT (Program Map Table) are required.

These information packets are inserted into the packet train at a predetermined time interval regardless of the GOP position of the video packet. Therefore, when the reproduction is started, the PAT and PMT cannot be immediately acquired.
Before decoding the GOP data, PAT and P
If MT data is not acquired, PI of video data
Since D is not decided, there is a problem that the data of the head GOP cannot be decoded.

Further, in the MPEG system, a PCR having time information is used to manage a time which is a reference for decoding.
(Program Clock Reference: Program Clock Re
ference) packet is inserted as appropriate. In the decoder, this time information is used to generate an operation clock of 27 MHz which is a reference for operation. When an operation such as scene skip is performed, the value of this time information becomes discontinuous, so that the operation clock becomes unstable and the decoding operation may be temporarily disabled.

Further, the video data must include picture data at a predetermined interval, but since the picture data is not output during a period during which the data is not reproduced, such as during seeking of the medium, the decoder does not output the video data. It had the drawback of not being able to play.

An object of the present invention is to provide a digital data reproducing apparatus which outputs data which can be correctly decoded without causing an abnormality in the operation of the decoder even when random access such as scene skip or high speed search occurs. To provide.

[0011]

In order to solve the above problems, a digital data reproducing device according to the present invention is a digital data reproducing device for reproducing compressed digital data in a packet format from a recording medium. The digital data is added with time information for managing a time that serves as a decoding reference when the data is decoded, and has time information conversion means for converting the time information in the reproduced data. The time information conversion means is configured to convert and output the time information so that the change amount of the time information per unit time becomes constant.

Further, in the digital data reproducing apparatus according to the present invention, time information indicating a display time and a decoding start time is added to each digital data for each picture, and the time information in the reproduced data is converted. And a time information conversion unit that
The time information is converted and output so that the amount of change in time information per unit time becomes constant.

Further, the digital data reproducing apparatus according to the present invention has packet generating means for generating a packet indicating time information for managing the time serving as a decoding reference when the data is decoded, The packet indicating the time information generated by the packet generating means is inserted into the packet sequence of No. 1 and output.

Further, in the digital data reproducing apparatus according to the present invention, the digital data is accompanied by the packet start number at the time of decoding the data and the packet identification number information of the start point, and the packet including the packet identification information. And a packet generating means for generating a packet including a packet identification number corresponding to the decoding start point before the reproduction of the data from the predetermined decoding start point is started.

Further, the digital data reproducing apparatus according to the present invention has the image data detecting means for detecting the image data from each packet of the reproducing data, and the packet generating means for generating the packet containing the image data. When the image data is lost, the packet generated by the packet generating means is inserted into the reproduction data and output.

A digital data recording apparatus according to the present invention records compressed digital data in a packet format on a recording medium, and the digital data recording time is a time indicating a display time and a decoding start time for each picture in the digital data. The time information adding means for adding information is recorded on the recording medium together with the digital data to which the time information is added, together with the information of the decoding start point and the packet identification number of the starting point when the data is decoded. It was configured to do.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A digital data recording apparatus and a reproducing apparatus according to the present invention will be described below with reference to embodiments. First, the recording device will be described. FIG. 1 shows an embodiment of a digital data recording device according to the present invention. 1
01 is an input terminal, 102 is an input interface, 10
3 is a control microcomputer, 104 is a packet detection unit, 105 is a reference signal generation unit, 106 is a time stamp addition unit, 10
7 is a buffer memory, 108 is a recording signal processing unit, 109
Is an optical head, and 110 is an optical disk.

An external device such as a digital broadcast receiver outside the recording / reproducing apparatus is connected to the input terminal 101. Compressed digital data input from an external device is input to the interface 102 via the input terminal 101. The interface 102 returns the input data to an MPEG transport packet having a length of 188 bytes, and the packet detection unit 104 and the reference signal generation unit 1
05, to the time stamp adding unit 106.

The packet detection unit 104 detects a PAT packet and a PMT packet in addition to the detection of the head packet of the GOP. The control microcomputer 103 detects the PAT packet and the PMT packet, analyzes the contents of these packets, and obtains the PID of the video packet and the PID of the audio packet. When a GOP head packet is detected, the packet position is stored as GOP head position information together with the video PID value and the audio PID value. Further, the control microcomputer 103 determines the PI of the PCR packet from the contents of the PAT packet and PMT packet.
D is obtained and set in the reference signal generator 105.

FIG. 2 is a block diagram of the reference signal generator 105. The reference signal generator generates a 27 MHz reference signal from the PCR value of the PCR packet in the MPEG transport packet. 201 is an input terminal to which an MPEG transport packet is input; 202 is an input terminal to which the PID value of the PCR packet is input from the control microcomputer;
203 is a PCR value detector, 204 is a PCR from a reference signal
A PCR counter that generates a value, 205 is an error voltage generator that calculates the difference between the count values of the PCR value detector and the PCR counter, and generates an error voltage, and 206 is a voltage control that finely adjusts the frequency according to the error voltage. An oscillator (VCO) 207 is an output terminal for outputting a reference signal.

The PCR value detector 203 is a control microcomputer 1
Using the PID of the PCR packet set from 03,
Only the PCR packet is extracted from the MPEG transport packet input to the input terminal 201, and the PC
Detect the R value. On the other hand, the voltage controlled oscillator 206 has 27
It oscillates the reference signal of MHz. This reference signal is P
It is input to the CR counter 204 and generates a PCR count value. The error voltage generator 205 calculates the PCR value from the PC
The R count value is subtracted, a voltage corresponding to the value is output as an error voltage, and the error voltage is supplied to the voltage controlled oscillator 206. M
When the frequency of the reference signal used when generating the PEG transport packet and the frequency of the reference signal generated by the voltage controlled oscillator match, the PCR value and the PC
The R count values match and the error voltage becomes zero.

On the other hand, when the frequency of the reference signal generated by the voltage controlled oscillator 206 is higher than the frequency of the reference signal used when generating the MPEG transport packet, the PCR count value is larger than the PCR value. Therefore, a negative value is obtained by subtracting the PCR count value from the PCR value. Therefore, the output voltage of the error voltage generator 205 is negative and the control voltage of the voltage controlled oscillator 206 is also a negative value. The voltage controlled oscillator 206 is designed to lower the oscillation frequency when the control voltage is negative,
The frequency of the reference signal generated by the voltage controlled oscillator 206 becomes slightly lower and approaches the reference frequency used when generating the MPEG transport stream.

On the contrary, when the frequency of the reference signal generated by the voltage controlled oscillator 206 is lower than the frequency of the reference signal used in generating the MPEG transport packet, the output voltage of the error voltage generator 205 Becomes positive,
Since the frequency generated by the voltage controlled oscillator 206 becomes slightly higher, it approaches the reference frequency used when generating the MPEG transport stream.

By the so-called PLL control as described above,
The frequency of the reference signal generated by the voltage controlled oscillator 206,
The frequencies of the reference signals used when generating the MPEG transport packet become equal. Voltage controlled oscillator 2
The reference signal generated by 06 is the time stamp adding unit 10
6 is supplied.

FIG. 3 shows the configuration of the time stamp adding section 106. Reference numeral 301 is an input terminal to which the reference signal supplied from the reference signal generator is input, 302 is a time stamp counter, 303 is an input terminal to which an MPEG transport packet is input, 304 is a buffer memory, and 305
Is a packet position detection unit for detecting the packet position of the MPEG transport packet, 306 is a switch for switching between the time stamp value and the output of the buffer memory, 3
Reference numeral 07 is an output terminal.

The time stamp counter 302 generates a time stamp based on the reference signal input from the input terminal 301. This time stamp has a length of 30 bits and counts up at 27 MHz which is a reference signal. The MPEG transport packet input from the input terminal 303 is input to the buffer memory 304 and the packet position detection unit 305. Buffer memory 304
Temporarily stores the MPEG transport packet.

The packet position detector 305 determines that an MPEG transport packet has been input, and determines the position to insert the time stamp from the packet position. At the time stamp insertion position, the switch 30
6 is switched to the time stamp counter side, and the time stamp value is supplied to the output terminal. Then, the switch 306 is switched to the buffer memory side, and the content of the MPEG transport packet stored in the buffer memory 304 is output to the output terminal 307.

FIG. 4 shows how a time stamp is added to an MPEG transport packet. Reference numeral 401 represents an input MPEG transport packet, and 402 represents an MPEG transport packet to which a time stamp is added. 1 MPEG transport packet
It has a length of 88 bytes. A 30-bit time stamp is added to the beginning of this MPEG transport packet. In addition, when it is converted to bytes, the division is not good with 30 bits, so additional information of 2 bits is added to make a total of 32 bits.
Bit (that is, 4 bytes) of information is added. As a result, the packet length becomes 192 bytes. The additional information 2 bits are used, for example, as copyright information indicating whether or not this program can be copied.

The data having the length of 192 bytes added with the time stamp is temporarily stored in the buffer memory 107 and then converted into a recording signal by the recording signal processing unit 108.
It is recorded on the optical disk 110 by the optical head 109.

FIG. 5 shows MPE for sectors of an optical disk.
The G packet storage method is shown. On an optical disc, data is recorded in units called sectors. 1 sector is 2
It is 048 bytes long. If 192 bytes of recording packets are packed in one sector, 10 packets can be recorded. However, there is a surplus of 128 bytes, which is inefficient. Therefore, as shown in FIG. 5, if 32 packets are recorded with 3 sectors as a group,
You can record without waste. The MPEG transport packets grouped into sectors are sequentially recorded in the MPEG packet recording area on the optical disc.

When the recording of the MPEG transport packet for one program is completed, the control microcomputer records the GOP information for the program as additional information in the additional information recording area on the optical disc. The recorded recording data for one program and the information such as the recording position and data length of the additional information are given a name for identification and registered as a file. Each file information is recorded in the file management information area.

FIG. 6 shows a used area of a sector on the optical disk. 601 is the first sector on the optical disc, 60
2 is the last sector on the optical disc, 603 is the file management information area, 604 is the additional information area, and 605 is MPEG.
Indicates a packet recording area. File management information area 603
And additional information area 604, MPEG packet recording area 60
5 is recorded in each independent area. This is to prevent each area from being dispersed on the disk and to minimize the seek time at the time of recording / reproducing. Furthermore, empty areas are provided at the beginning and the end of the optical disc. This can be used in an area for recording other file management information in the future or for recording BOOT information read when the reproducing apparatus is activated.

FIG. 7 shows an example of recording GOP information. GO
The position of the packet in which the leading position of P is detected and the value of the video PID and the audio PID at that time are paired and recorded as GOP information. When a scene is skipped or a high speed search is performed, reproduction is started from the GOP head position using this GOP information.

Next, the reproducing apparatus will be described. Figure 8
Shows an embodiment of a digital data reproducing apparatus according to the present invention. Reference numeral 110 is an optical disk as a recording medium,
Is a pickup that reads the data on the optical disc, 801
Is a reproduction signal processing unit, 802 is a buffer memory, 803 is an output timing control unit that controls the packet output timing according to the time stamp added to the reproduction packet, 804 is a control microcomputer, 805 is a packet filter, and 806 is time information. A conversion unit, 807 is a packet generation unit, 808 is a packet mixing unit, 809 is an output interface, and 810 is an output terminal.

At the time of reproduction, first, the control microcomputer 804
Reads the file management information from the optical disc 110 in a predetermined procedure. In the file management information, information about what file is written at which position on the disc is written. Based on this file management information, the control microcomputer 804 acquires the program name recorded on the disc, the information of the MPEG packet recording area corresponding to the program, and the GOP information.

Next, the program information is displayed on the screen,
Prompt the user to select a program. The user selects a desired program and gives an instruction to start reproduction. Control microcomputer 8
04 reads the information of the file corresponding to the program selected by the user. This information includes MPEG
There is a start position / data length of the packet recording area and GOP information.

Next, the MPEG of the designated program
Data is read from the packet recording area and reproduced.
The data read from the optical disk 110 is once input to the buffer memory 802. The data read from the optical disc has the sector format shown in FIG. The data for 3 sectors is divided into 32 MPEG packets with time stamps and input to the output timing control unit 803.

FIG. 9 is a block diagram of the output timing control unit 803. Reference numeral 901 is an input terminal to which a reproduction packet is input, 902 is a reference signal generation unit, 903 is a time stamp counter, 904 is a time stamp value detection unit, and 905.
Is a time stamp value comparison unit, 906 is a buffer memory,
Reference numeral 907 is a packet read control unit, 908 is a time stamp removal unit, and 909 is an output terminal.

The input terminal 901 is reproduced from the optical disk.
The more time-stamped packet input is input to the time stamp detection unit 904 and the buffer memory 906. Here, the input packet with the time stamp is a 188-byte MP as shown in 402.
It has a shape of 192 bytes in which 30-bit time information and 2-bit additional information are added to the EG transport.

The time stamp detector 904 detects the value of the time stamp added to the input packet. On the other hand, the reference signal generation unit 902 independently generates the 27 MHz reference signal. This reference signal is input to the time stamp counter 903. The time stamp counter 903 counts up by 1 each time a 27 MHz reference signal is input, and generates a time stamp value. The time stamp comparator 905 includes the first time stamp detected by the time stamp detection unit,
The second time stamps generated by the time stamp counters are compared, and when these values match, the packet read control unit 907 is instructed to start reading.

The packet read control unit 907 reads a packet from the buffer memory 906 according to the read start instruction from the time stamp comparator 905. The read packet data has its time stamp removed by the time stamp removing unit 908, and is output from the output terminal 909 as a 188-byte MPEG transport packet as indicated by 401. As described above, the data read from the optical disc is
It is played back in the form of MPEG transport packets having the same packet intervals as when recording.

Subsequently, this MPEG transport packet is input to the packet filter unit 805. The packet filter section deletes unnecessary MPEG packets. The discrimination of the packet is performed by using the PID added to each packet. When all the PCR packets are replaced and output, the PCR packets are all deleted, and the packet generation unit 807 generates and outputs a new PCR packet. Similarly, when recreating all PATs and PMTs, all PATs and PMTs are deleted and the packet generation unit 80
The PAT / PMT generated in 7 may be output.

The packet selected by the packet filter unit 805 and output to the decoder is the time information conversion unit 8.
It is input to 06. In the time information conversion unit 806, the MPE
The time information included in the G transport packet is converted into one corresponding to the internal PCR value. The time information included in the MPEG transport packet includes PC
There are R, PTS and DTS. Of these, PCR is
It is not processed here because it is deleted by the packet filter 805 and replaced by the PCR packet newly generated by the packet generation unit 807.

The PTS / DTS is added as required for each video picture or audio decoding unit in the MPEG packet. The PTS indicates the display time of the picture or the output start time of the audio decoding unit. DT
S represents the decoding start time of the picture. In the reproducing apparatus according to the present invention, since the PCR packet is replaced and the reference time in the decoder is changed, P
As with the PCR packet, it is necessary to convert the time information for the TS / DTS.

FIG. 10 shows a block diagram of the time information converter 806. Reference numeral 1001 denotes an input terminal to which a reproduced MPEG packet is input, 1002 denotes a picture number calculation unit, 10
Reference numeral 03 is a buffer memory, 1004 is a PTS / DTS position detection unit, 1005 is a PTS value calculation unit, and 1006 is a DTS.
A calculator, 1007 is a switch, and 1008 is an output terminal.

Playback MP input from the input terminal 1001
The EG packet includes a picture number calculation unit 1002, a buffer memory 1002, a PTS / DTS position detection unit 1004.
Entered in. The picture number calculation unit 1002 uses the MPE
The number of GOP headers and picture headers in the G packet is counted, and the number of pictures reproduced from the beginning of the program is calculated.

The PTS value calculation unit 1005 calculates the PTS value from the picture number calculated by the picture number calculation unit. The PTS represents the display time of the image, and its value has a length of 33 bits. PTS is 27MHz
Is generated on the basis of a 90 KHz signal obtained by dividing by 300, and counts up by 90,000 per second. N
The TSC system displays 29.97 images per second.
Therefore, if the PTS and DTS are increased by 3003 for each picture, all the images can be continuously displayed at a predetermined timing. The DTS represents the code start time of an image, and its value has a length of 33 bits. DTS also divides 27 MHz by 300 9
It is generated based on a 0 KHz signal, and 90 seconds per second.
Count up by 000. Since the DTS may take the same value as the display time of the immediately preceding picture, P
A value smaller than TS by 3003 is set.

The PTS / DTS position detector 1004 detects the PES header in the input MPEG packet and detects the PTS position / DTS position contained in the header. When reading a PTS recording position when reading an MPEG packet from the buffer memory 1003, the switch 1007 is switched to the output of the PTS value calculation unit, and P
The TS value is output to the output terminal 1008. Similarly, when the data read from the buffer memory 1003 corresponds to the DTS, the switch 1007 is switched to the output of the DTS value calculator, and the DTS value is output to the output terminal 1008. The data read from the buffer memory 1003 is PT
If it does not correspond to S or DTS, the switch 1007 is switched to the buffer memory side, and the data read from the buffer memory 1003 is output to the output terminal 1008.

By the above processing, the input terminal 100
PTS and D in MPEG packet input from 1
Each TS can be converted into a value obtained by calculation. The MPEG transport packet in which the PTS / DTS is converted is output from the output terminal 810 to an external decoder via the packet mixing unit 808 and the interface 809.

Here, the operation of the reproducing apparatus when the screen skip operation is performed during reproduction will be described. FIG. 11 shows a comparison between reproduced data and output data during the screen skip operation. 1101 is reproduction data reproduced from the recording medium, 1
Reference numeral 102 indicates packet identification information for identifying an image packet, and 1103 indicates inserted picture data.

When the scene skip operation is specified by the user during reproduction, it is necessary to interrupt the data reproduction from the currently reproduced sector and reproduce the data from the specified scene. In such a case, in the reproducing apparatus according to the present invention, the MPEG packet currently being reproduced is output up to a break such as a GOP break, and then the PAT based on the video PID value / audio PID value in the GOP information.・ PMT
Is generated and output from the packet generation unit 807. These pieces of packet identification information are shown in 1102.

Then, the output of data is restarted from the GOP head position of the designated scene. At this time, the GOP head position, the video PID value, and the audio PID value are read from the recording medium in advance as GOP information as shown in FIG. 7 and stored in the control microcomputer, so that the reproduction start sector position can be easily obtained. You can

By the way, since the data being reproduced changes from the middle along with the scene skip, the time information becomes discontinuous. With correct data, the increment of time information per unit time must always be constant. In the conventional reproducing apparatus, since the data is supplied to the decoder while the time information of the output data is discontinuous, the decoder temporarily stops the decoding process. As a result, the operation of the decoder becomes unstable and there is a possibility that the screen cannot be displayed. Also, if the PIDs of video packets and audio packets change before and after the scene skip, decoding may not be possible.

In the reproducing apparatus according to the present invention, PCR is newly generated and output by the control microcomputer 804 and the packet generator 807, so that even if a scene skip occurs, the increment of PCR per unit time is kept constant. Can be kept at Further, since PTS / DTS is also converted into time information corresponding to PCR by the time information conversion unit 806, discontinuity does not occur. Therefore,
MPEG, which is supplied to the decoder like a conventional playback device
The operation of the decoder does not become unstable due to the occurrence or discontinuity of the amount of change in the packet time information per unit time.

Next, another embodiment of the digital data reproducing apparatus according to the present invention will be described. When the scene skip as described above is performed, if the read position on the optical disc is significantly different, it may take time to read the data. In addition, the reading of data may be temporarily interrupted due to scratches on the disk or the influence of external vibration.

In such a case, the output of the MPEG packet is continued while the data is accumulated in the buffer memory 802, but if the reading of the data is stopped for a long time, the output of the MPEG packet is stopped.
When the output of the MPEG packet is stopped, the packet input to the decoder is also stopped, so that the decoding cannot be performed.

The PCR packet is specified by the standard to be input at least once every 100 milliseconds.
The loss of packets can cause problems in generating the reference signal in the decoder. Therefore, in the reproducing apparatus of the present invention, independently of the data reading from the optical disc,
A PCR packet is generated by the packet generation unit 807 at predetermined intervals and inserted into the MPEG packet.

When the data reading from the optical disk 110 is stopped for a long time, the video data may not be output. In this case, in the decoder, there is a possibility that the image display will be stopped, the screen will be blackened, or a blue back display will be performed, assuming that the video data has ended. If the data from the optical disk is output again, the image is displayed, but it is not preferable that the screen is interrupted at this time.

Therefore, in the reproducing apparatus according to the present invention, when data reproduction from the optical disk 110 is interrupted,
The picture data 1103 is inserted at a predetermined interval, and control is performed so that the image display of the decoder is continued. Specifically, the control microcomputer 804 determines that the data reproduction from the optical disc has been interrupted for a predetermined time or longer, and the packet generation unit 807 generates and outputs a packet including picture data. The generated packet is sent to the packet mixing unit 8
08 and interface 809, output terminal 8
It is output from 10 to the external decoder.

By the above processing, even if the data reproduction from the optical disk is interrupted, the decoder can be stably operated by continuously supplying the packets. In addition, even when a predetermined number of pictures are reproduced from the recording medium in a scattered manner, such as during high-speed search, the time information is converted into continuous information and output, so that the operation of the decoder is stable.

In the above description, the case where the optical disk is used as the recording medium has been described as an example, but the present invention can be applied to the case of other recording medium such as a hard disk and a semiconductor memory.

[0062]

According to the present invention, the time information converting means for converting the time information in the reproduced data is provided, and the time information is converted so that the change amount of the time information per unit time becomes constant. Therefore, even when the time information in the reproduced data is discontinuous, the time information in the reproduced data does not become discontinuous, and the decoder for decoding the reproduced data operates stably.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a digital data recording device according to the present invention.

FIG. 2 is a configuration diagram of a reference signal generator in FIG.

FIG. 3 is a configuration diagram of a time stamp adding unit in FIG.

FIG. 4 is a method of adding a time stamp to a packet in FIG.

FIG. 5 is a method of storing packets in a recording sector in FIG.

FIG. 6 is a layout diagram of recording areas on an optical disc.

FIG. 7 is a method of storing GOP information in FIG.

FIG. 8 is a configuration diagram showing an embodiment of a digital data reproducing device according to the present invention.

9 is a configuration diagram of an output timing control unit in FIG.

10 is a configuration diagram of a time information conversion unit in FIG.

FIG. 11 is a comparison diagram of reproduced data and output data in FIG.

[Explanation of symbols]

101 ... Input terminal, 102 ... Input interface, 1
03 ... Control microcomputer, 104 ... Packet detection unit, 105
Reference signal generating unit, 106 Time stamp adding unit, 1
07 ... Buffer memory, 108 ... Recording signal processing unit, 11
0 ... Optical disc, 401 ... Input MPEG transport packet, 402 ... Recording MPEG transport packet, 801 ... Reproduction signal processing unit, 802 ... Buffer memory, 803 ... Output timing control unit, 804 ... Control microcomputer, 805 ... Packet filter, 806 ... time information conversion unit, 807 ... packet generation unit, 809 ... output interface, 1002 ... picture number calculation unit, 1003 ...
Buffer memory, 1004 ... PTS / DTS position detection unit, 1005 ... PTS value calculation unit, 1006 ... DTS value calculation unit, 1007 ... Switcher 1101, ... Playback data,
1102 ... Packet identification information 1103 ... Inserted picture data

Continued front page    (72) Inventor Katsuyuki Watanabe             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Ceremony Hitachi Digital Media Development Book             Department F-term (reference) 5C053 GB06 GB08 GB21 GB38 HA21                       JA21 LA06 LA11                 5D044 AB05 AB07 BC08 CC09 DE17                       DE38 EF05 FG18 FG23                 5D077 BA04 BA08 CA02 DC03 DC22                       DC35 EA06

Claims (8)

[Claims] 1. A digital data reproducing apparatus for reproducing compressed digital data in a packet format from a recording medium, wherein the digital data includes a time for managing a decoding reference time when the data is decoded. Information is added, and there is provided time information conversion means for converting the time information in the reproduced data, and the time information conversion means is such that the amount of change in time information per unit time is constant. A digital data reproducing apparatus characterized in that the time information is converted and outputted. 2. A digital data reproducing apparatus for reproducing compressed digital data in packet format from a recording medium, wherein the digital data is added with time information indicating a display time and a decoding start time for each picture. The time information conversion means for converting the time information in the reproduced data, the time information conversion means converting the time information so that the amount of change in the time information per unit time becomes constant. A digital data reproducing device characterized by performing and outputting. 3. A digital data reproducing apparatus for reproducing compressed digital data in a packet format from a recording medium, and generating a packet indicating time information for managing a decoding reference time when the data is decoded. A digital data reproducing apparatus having a packet generating means for reproducing, and inserting and outputting a packet indicating time information generated by the packet generating means into a packet string in the reproduced data. 4. The digital data reproducing apparatus according to claim 3, further comprising packet selecting means for selecting and outputting a packet in the reproduced data, and deleting a packet indicating unnecessary time information in the reproduced data. A digital data reproducing device characterized by: 5. The digital data reproducing apparatus according to claim 1, wherein the time information includes a program clock reference. 6. A digital data reproducing device for reproducing packetized compressed digital data from a recording medium, the image data detecting means for detecting image data from each packet of the reproduced data, and a packet containing the image data. A digital data reproducing apparatus having a packet generating means for generating, and inserting and outputting the packet generated by the packet generating means into the reproduced data when the image data is missing in the reproduced data. 7. A digital data reproducing apparatus for reproducing compressed digital data in a packet format from a recording medium, wherein the digital data includes a decoding start point for decoding the data and a packet identification number of the starting point. Of packet identification information, and a packet generation means for generating a packet including packet identification information. Before starting reproduction of data from a predetermined decoding start point, a packet identification number corresponding to the decoding start point is provided. A digital data reproducing device characterized by outputting a packet containing the data. 8. A digital data recording apparatus for recording compressed digital data in a packet format on a recording medium, wherein time information is added to the digital data for displaying time and decoding start time for each picture. With addition means, together with the digital data to which the time information is added,
A digital data recording device, characterized in that information on a decoding start point and a packet identification number of the starting point when the data is decoded is recorded on the recording medium.