JP3147694B2 - Packet data recording device and packet data reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet data recording apparatus and a packet data reproducing apparatus suitable for recording and reproducing a data stream conforming to the MPEG standard.

[0002]

2. Description of the Related Art In recent years, MPEG (Moving Picture Exper
With the establishment of image compression techniques such as ts Group 2), digitization of images is progressing. Also in television broadcasting, digital broadcasting employing the MPEG2 system has been studied. In addition, multimedia services that can handle audio and video in an integrated manner and can provide various information services in the form of images in response to user requests are also being developed. In the MPEG2 standard, DCT (Di
A video signal is encoded by using a combination of a Cosine Transform (transform), an inter-frame prediction encoding, a run-length encoding and an entropy encoding. That is, in the MPEG system, not only compression by DCT (intra-frame compression) within one frame, but also inter-frame compression that reduces the redundancy in the time axis direction by using correlation between frames is adopted.

[0003] MPEG2 has a system corresponding to multi-channel broadcasting and multi-media in communication or storage media. That is, MPEG2 is designed to transmit transmission data in packet units in order to facilitate time-division multiplexing of a plurality of images, sounds, data, and the like. One packet is composed of the same type of data,
An identification signal (PID) indicating the type of data is added to each packet. As a result, not only image and audio data but also predetermined private data can be transmitted at the same time, and can be used in the broadcasting, communication, or storage fields.

FIG. 6 is an explanatory diagram showing the structure of a transport packet which is a transmission unit in the MPEG2 standard.

A transport packet corresponds to a multi-program (channel), and a packet of a desired program can be selected from a plurality of programs transmitted in a time-division manner at the time of decoding. For this selection, the transport packet is transmitted with a link level header (Link Level Header) added before the payload (Payload) for transmitting information, as shown in FIG. 4 out of 188 bytes of transport packet
The bytes are the link level header. A PES (Pecketized Eleme) is transmitted by several transport packets.
ntary Stream Packet) packet.

[0006] The link level header has a synchronization byte (sync_byte) at the head thereof, and thereafter, an error indicator (transport packed error ind) indicating presence or absence of a bit error.
icator), a unit start display indicating the start of the PES packet (PES packet start indicator), and a transport packet priority (transp indicating the importance of the packet)
ort priority), and PID (Pa
cket identification), scramble control indicating the presence or absence of scrambling (stransport scrambling control),
An adaptation field control indicating the presence / absence of a payload, and a continuity counter indicating continuity of the same PID are sequentially arranged. The 8-bit synchronization byte at the head of the packet is a specific code, and always has a value of 47 in hexadecimal.

[0007] The MPEG2 decoder has a function of extracting packets of the same PID by referring to the PID from sequentially input packets, thereby decoding only a desired program from transmission data. . For example, even when a transport stream including video data, audio data, and other data is input,
If a television receiver compatible with the PEG2 standard is used, it is possible to decode and project video data.

Further, the PID of each packet can be set arbitrarily on the transmitting side, and it is necessary to clarify the correspondence between the PID and information such as the type indicated by the PID at the time of transmission. For this reason, in the transport stream, an identification table describing a list of PIDs and the like is transmitted by a predetermined transport packet (program map table (PMT) packet),
A transport packet (program association table (PAT) packet) indicating the PID of the MT packet is transmitted. The PID of this PAT packet is set to 0. The PAT and PMT packets are transmitted at predetermined intervals. The transmitted PMT packet is valid until updated by the next PMT packet. The MPEG2 decoder recognizes the relationship between the PID and the data type by referring to the PMT packet identification table.

FIG. 7 is an explanatory diagram showing a transport stream in which a plurality of types of data are transmitted by transport packets which are transmission units in the MPEG2 standard.

In FIG. 7, a transport stream 1 is composed of packets based on video data, audio data, and other data. The number of each packet in FIG. 7 indicates the PID, and the PIDs of the PAT and PMT packets are 0 and 13, respectively. PAT packet 2 with PID 0 at the beginning of transport stream 1
Are arranged, and then the PMT packets 3 are arranged and transmitted. PAT packet 2 causes PMT packet 3 P
It is shown that the ID is 13. The identification table of the PMT packet 3 indicates that the PID of the video packet is 19, the PID of the audio packet is 20, and the PIDs of the other packets are 21. That is, as shown by the PID in FIG. 7, the transport stream 1 includes PAT, PMT packets 2 and 3, followed by video packets, audio packets, video packets, video packets, other packets, video packets, and so on. Packets are arranged and transmitted.

Further, the PID packet 4 transmitted second indicates that the PID of the PMT packet 5 is 13, and according to the identification table of the PMT packet 5,
The PID of the subsequent video packet is 39, the PID of the audio packet is 40, and the PID of the other packets is 41. Thus, in FIG. 7, the transport stream 1 is composed of a video packet, a video packet, an audio packet,
It can be seen that packets are arranged and transmitted in the order of video packets, other packets, video packets,...

Incidentally, it is conceivable that such a transport stream is recorded by a VCR (Video Tape Recorder). A helical scan type VCR reads information recorded on a magnetic tape by tracing a recording track formed on the magnetic tape with a rotating drum head. Normal reproduction is performed by matching the rotational speed of the rotary drum head and the tape running speed of the magnetic tape during recording and reproduction, and by matching the recording track pattern with the head trace pattern during reproduction.

On the other hand, at the time of trick play, the tape running speed is changed according to the double speed. In this case, the head traces while traversing the recording track. Then, of the traced portion, only the data of the portion where the azimuth of each head and the recording track match is reproduced. Even in this case, one screen can be reproduced in analog recording in which the position on the screen corresponds to the recording position on the recording medium.

However, when image data compressed by the MPEG system is recorded on a recording medium, the code amount is different between the intra-frame compressed frame and the inter-frame compressed frame. Does not correspond to the vertical recording position on the recording medium, and it is not always possible to reproduce one frame by the reproduction data at the time of high-speed reproduction. Furthermore, since an inter-frame compressed frame cannot be decoded by a single frame, when a frame that cannot be decoded occurs, such as during high-speed playback, playback becomes impossible.

Therefore, in the specification of Japanese Patent Application No. 6-065298 filed earlier by the present applicant, data for high-speed reproduction is intermittently recorded at the position of each track through which the head passes during high-speed reproduction. A way to do that has been proposed. At the time of reproduction, a high-speed reproduction image is obtained by accurately tossing an area in which high-speed reproduction data is recorded.

FIG. 8 is an explanatory diagram for explaining a head trace in this proposal. Hereinafter, in order to simplify the description, the azimuth of each head and the recording track is described without consideration.

A recording track 7 is formed on the magnetic tape 6. At the time of recording, the magnetic tape 6 runs to the left in FIG. During high-speed reproduction, the trace loci 8 of the head straddle a plurality of recording tracks 7. The trace locus 8 in FIG. 8 is for reverse high-speed reproduction, and has an inclination based on the double speed number. When the tracking phase is controlled, there is a special reproduction data recording area T (T1, T2,...) Which is always traced during high-speed reproduction. The trick play data recording area T can be traced by head tracing during high-speed playback, and the trick play data recorded in this area T can be played back.

That is, in this proposal, at the time of recording,
The input encoded data is recorded as data for normal reproduction in an area other than the special reproduction data recording area T. on the other hand,
The special reproduction data is created by using, for example, the in-frame compressed data of the video data among the encoded data, and the special reproduction packet is packetized and recorded in the special reproduction data recording area T.

FIG. 9 is an explanatory diagram showing a data stream recorded in the special reproduction data recording area T. The numbers in FIG. 9 indicate the numbers of the special reproduction packets, and the recording is performed in the order of the numbers.

Since the special reproduction data is a variable length code,
The number of packets differs for each special reproduction frame. FIG. 9 shows that the first special reproduction frame is composed of the first to eleventh eleventh packets and the second special reproduction frame is the twelfth to eighteenth seventeenth packets.
This shows an example composed of packets. By the way, in the SD format of the consumer digital VTR, recording is performed on each track in units of one sync block, and one sync block is 90 bytes long. The transport packet length of the MPEG2 is 188 bytes as shown in FIG.
Two packets are allocated to the sync block and recorded.

Now, 10 special reproduction data recording areas T
It is assumed that a sync block can be allocated and recorded. That is, four packets of packet data can be recorded in one special reproduction data recording area T. For example,
Assuming that the first to fourth packets are recorded in the special reproduction data recording area T1 of FIG. 8, the fifth to eighth packets, ninth to twelfth packets, and thirteenth packets are respectively recorded in the special reproduction data recording areas T2 to T5. Thirteenth packet and seventeenth packet
-20th packet can be recorded.

At the time of forward reproduction, the magnetic tape 6 runs to the left in FIG. 8 as in recording, and the head sequentially reproduces from the left track to the right track in FIG.
That is, at the time of forward high-speed reproduction, reproduction is performed from the special reproduction data recording area on the left side of FIG. 8 to the special reproduction data recording area on the right side. If the special reproduction data recording areas T1, T2,... Can be reproduced by high-speed reproduction in the forward direction, the first, second, third,. , The second special reproduction frame can be sequentially restored.

However, during high speed reproduction in the reverse direction,
The magnetic tape 6 runs in the direction of the arrow in FIG. 8, and the reproduction is performed in the order of the special reproduction data recording areas T5, T4, T3,. That is, first, from the special reproduction data recording area T5 to the first
The 7, 18, 19, and 20 packets are reproduced, and then the 13, 13, 15, and 16 packets are reproduced from the special reproduction data recording area T4. Similarly, the data is reproduced in the order of the special reproduction data recording areas T3, T2, T1,
0, 11, 12 packets, 5, 6, 7, 8 packets,
The packet data is reproduced in the order of the first, second, third and fourth packets.

In order to restore each special playback frame,
It is necessary to arrange the packet data in the original recording order in frame units. FIG. 10 is an explanatory diagram showing a packet arrangement necessary for reverse reproduction. As shown in FIG. 10, for reverse reproduction, the time order of a series of screens is reversed, and the packet data of each screen is arranged in the encoding order corresponding to the position of the screen. That is, the twelfth to eighteenth packets and the first to eleventh packets must be arranged in this order.

Such rearrangement of reproduction data requires information for identifying a packet at the boundary between special reproduction frames. Therefore, conventionally, there has been a problem that a flag for identifying a boundary between frames must be recorded in packet units or sync block units in order to enable reverse reproduction.

[0026]

As described above, conventionally, in order to restore a special reproduction frame, it is necessary to rearrange the reproduced packet data in frame units.
There is a problem that information indicating that the packet is at the boundary between frames must be recorded in packet units or sync block units.

According to the present invention, by recording a packet having a specific packet ID for every predetermined number of packets corresponding to a special reproduction screen, information indicating a packet at a boundary between frames is transmitted in packet units or sync blocks. An object of the present invention is to provide a packet data recording device capable of restoring data without recording in units.

Further, the present invention provides a packet data reproducing apparatus capable of restoring data without recording information indicating a packet at a boundary between frames in a packet unit or a sync block unit. With the goal.

[0029]

According to a first aspect of the present invention, there is provided a packet data recording apparatus comprising: a plurality of types of data which are time-division multiplexed in predetermined packet units, and each packet includes a packet ID indicating the type; Special reproduction data packetizing means for generating special reproduction data from the input packet data sequence into which the special reproduction data is inserted and converting the generated special reproduction data into packet units and outputting the packet, and each special reproduction screen corresponding to the special reproduction data. A packet having a specific packet ID is inserted for each predetermined number of packets corresponding to each of the special reproduction screens output from the special reproduction data packetizing means to indicate a boundary of the special reproduction packet. Inserting means for recording the trick play packet in a trick play data recording area at a predetermined position of a track formed on the magnetic tape; Are those provided with the recording means,
A packet data reproducing apparatus according to claim 5 of the present invention reproduces the magnetic tape recorded by the packet data recording apparatus according to claim 1, and reproduces the magnetic tape obtained by reproducing the magnetic tape. And a rearrangement unit for rearranging the reproduced data in packet units based on a detection result of the specific packet detection unit during reverse high-speed reproduction. It was done.

[0030]

According to the first aspect of the present invention, the trick play data packetizing means creates trick play data from an input packet data string, converts the trick play data into packet units, and outputs the packet. In the output packet data string, a packet having a specific packet ID is inserted for each predetermined number of packets corresponding to the special reproduction screen by the specific packet inserting means. The packet position corresponding to the boundary between the special reproduction screens is clarified by the insertion position of the packet having the specific packet ID. The storage unit records the special reproduction packet into which the packet having the specific packet ID is inserted in the special reproduction data recording area of the magnetic tape.

In claim 7 of the present invention, the reproduced data is supplied to a specific packet detecting means to detect a packet having a specific packet ID. The specific packet detecting means is:
A packet corresponding to the boundary of the trick play screen is detected from the detected position. On the basis of this detection result, the rearranging means rearranges the packets for each special reproduction screen during reverse high-speed reproduction.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of a packet data recording device according to the present invention.

The input terminal 10 receives, for example, packet data such as a transport stream of the MPEG2 standard. As packet data, other packets for other data are transmitted in addition to video packets for video data and audio packets for audio data. Each packet data has a PID, and the type of the packet data can be determined based on the PID. Also, an identification table indicating the relationship between the PID and the type is transmitted by a PMT packet, and the PI
The information indicating D is transmitted by a PAT packet.

The input packet data is supplied to a multiplexer (hereinafter, referred to as MPX) 11 and also to a demultiplexer (hereinafter, referred to as DMPX) 12.
The DMPX 12 detects a PID included in the packet data and decodes a PAT packet and a PMT packet having a specific PID. DMPX12 is the PI of each packet.
The packet data is separated for each type based on D and the decoding result, and a PAT packet, a PMT packet, and a video packet are output to the trick play packet creation unit 13. The trick play packet creation unit 13 creates a trick play packet based on the input packet data. This embodiment shows an example in which only video packets are used to create special reproduction data.

FIG. 2 shows a special reproduction packet creating unit 13 in FIG.
FIG. 3 is a block diagram showing a specific configuration of FIG.

The video packet is supplied to a depacketizer 16 via a terminal 15 and the PAT and PMT packets are supplied to a terminal 17.
Is supplied to the PAT and PMT memory 18 via the PAT. The depacketizing unit 16 depacketizes the video packet, restores the encoded video data stream before packetization, and outputs it to the trick play stream creating unit 19. The trick play stream creation unit 19 creates a trick play data stream, for example, by extracting a part of the input video data stream. For example,
The trick play stream creation unit 19 extracts the in-screen compressed data and various header information as a trick play data stream. Also, for example, the trick play stream creation unit 19
The DC component of the DCT transform coefficient and various header information in the in-screen compressed data may be extracted as a special reproduction data stream. The special playback stream creation unit 19
May use inter-screen compressed data as a trick play data stream. The trick play stream creation unit 19 outputs the created trick play data stream to the packetizing unit 20. The packetizing unit 20 converts the input trick-play data stream into packet units, creates trick-play video packets, and outputs it to the MPX 21.

The trick play stream creating section 19 supplies the start position information of the trick play frame to the PAT / PMT memory 18 when creating the trick play data stream. The PAT / PMT memory 18 records the PAT / PMT packet input via the terminal 17 and outputs the stored PAT / PMT packet to the MPX 21 at a timing based on the head position information. . The MPX 21 multiplexes the PAT / PMT packet from the PAT / PMT memory 18 and the special reproduction video packet from the packetizing section 20 and outputs the multiplexed special reproduction packet to the MPX 11 via the output terminal 22. .

The packet data input via the terminal 10 is also supplied to the MPX 11. The MPX 11 has a buffer (not shown), holds the special reproduction packet from the special reproduction packet creation unit 13 and the input packet data, and performs special reproduction at a timing corresponding to the special reproduction data recording area of the magnetic tape. A packet is output, and at another timing, the input packet data is output as a normal reproduction packet. The output of the MPX 11 is recorded on a recording medium after performing a recording format process, an error correction code adding process, a modulation process, and the like.

Next, the operation of the embodiment configured as described above will be described with reference to FIG. FIG. 3 is an explanatory diagram showing the output of MPX21. In FIG. 3, the shaded area is PAT.
Packets are shown, and hatched portions indicate PMT packets.

The packet data input via the input terminal 10 is given to the DMPX 12. The DMPX 12 detects the PID of the packet data. For example, M as packet data
Assuming that a transport packet conforming to the PEG2 standard is given, the DMPX 12 detects the PID of the PMT packet from the PAT packet with the PID of 0, and identifies the type of each packet from the PMT packet identification table. DMP
X12 classifies each packet into video packets, audio packets, PAT, PMT packets and other packets. DMPX12 is for video packet and PAT, PM
The T packet is output to the trick play packet generator 13.

Now, the PAT packet indicates that the PID of the PMT packet is 13, and the PMT packet
Assume that the packet indicates that the PID of the video packet is 19. In FIG. 2, the PID is 1
The video packet 9 is supplied to the depacketizing section 16 of the trick play packet creating section 13 to be depacketized. The depacketizing unit 16 converts the input video packet back to the encoded bit stream of the original video, and
Give to.

The trick play stream creation section 19 creates a trick play data stream using, for example, in-screen compressed data from the input bit stream. In this case, the trick play stream creation unit 19 outputs the head position information every time a trick play data stream based on a different trick play frame is output, that is, at the start timing of the trick play frame. The created special reproduction data stream is packetized again by the packetizing unit 20. The trick play video packet from the packetizer 20 is supplied to the MPX 21.

On the other hand, the PAT / PMT memory 18 has a terminal 17
, PAT and PMT packets are provided. PA
The T and PMT memory 18 stores the PAT packet and the PMT packet, and outputs the stored PAT and PMT at a timing based on the head position information. PAT, PMT
PAT packet and PMT packet from memory 18 are MP
Give to X21.

Now, it is assumed that nine trick-play video packets are created by a trick-play data stream based on the first trick-play frame. MPX21 is shown in FIG.
As shown in the figure, a PAT packet and a PMT packet are added to the head of these nine special reproduction video packets and output. In FIG. 3, the PID of the PAT packet is 0, the PID of the PMT packet is 13, and the PID of the special playback video packet is the first special playback frame.
Is 19.

Next, it is assumed that five trick-play video packets are created by a trick-play data stream based on the second trick-play frame. Note that the PMT of the PMT is used for the original second frame of the second trick play frame.
The ID is 13 and the PID of the video packet is 39.
PAT and PMT packets from terminal 17 are PAT and PMT
It is supplied to the MPX 21 via the memory 18. Thus, FIG.
As shown in (5), MPX21 puts these PAT, P at the beginning of the five special reproduction video packets of the second special reproduction frame.
An MT packet is added and output.

Next, it is assumed that eight trick-play video packets are created by a trick-play data stream based on the third trick-play frame. Note that the PMT of the PMT for the third frame, which is the original of the third special reproduction frame,
The ID is 15, and the PID of the video packet is 25.
PAT and PMT packets from terminal 17 are PAT and PMT
It is supplied to the MPX 21 via the memory 18. Thus, FIG.
As shown in the figure, the MPX 21 puts these PAT, P at the beginning of the eight special reproduction video packets of the third special reproduction frame.
An MT packet is added and output.

The special reproduction packet from the MPX 21 is supplied to the terminal 22.
To MPX11 via. Special playback packet is MPX
Keep in the buffer in 11. On the other hand, the packet data input from the input terminal 10 is also supplied to the MPX 11 and stored in a buffer (not shown). The MPX 11 outputs a special reproduction packet during a period corresponding to the special reproduction data recording area of the magnetic tape, and outputs packet data from the input terminal 10 during a period corresponding to an area other than the special reproduction data recording area. The output of the MPX 11 is supplied as recording data to a recording unit (not shown), and a predetermined header and an error correction code are added thereto, and a predetermined modulation process is performed to record the data on a magnetic tape.

As described above, in the present embodiment, the trick play packet to be recorded in the trick play data recording area is created by inserting the PAT packet and the PMT packet for each trick play frame, so The reproduced packet at the boundary between the special reproduction frames can be determined without inserting a flag indicating the frame boundary in block units, and the packets in the special reproduction frame unit can be rearranged. For this reason, a series of special reproduction frames can be decoded in reverse order to perform reverse reproduction.

In this embodiment, the packetizing unit
Reference numeral 20 uses the same PID as the PID of the packet data input via the terminal 15 as the PID of the trick play video packet, but changes the data in the PAT and PMT memory 18 to match the PID of the input packet data. Different PIDs may be set.

FIG. 4 is a block diagram showing one embodiment of the packet data reproducing apparatus according to the present invention. This embodiment is shown in FIG.
In this embodiment, the magnetic tape recorded by the packet data recording apparatus of the embodiment is reproduced to restore a reproduced image.

The input terminal 31 is supplied with reproduced packet data. The reproduced packet data is obtained by demodulating data reproduced from a recording medium, performing error correction processing, and then performing recording unformat processing. The reproduced packet data is supplied to the terminal a of the switch 32 and the packet start position detecting unit 33.

The packet start position detecting section 33 detects the packet head position of the reproduced packet data using, for example, a synchronization byte. As described above, when the packet length is 188 bytes, the synchronization byte is transmitted periodically every 188 bytes, so that the start position of the packet can be detected by the synchronization byte. Since the synchronization byte is a specific code, the recording device sometimes removes the synchronization byte. But even in this case,
By inputting information according to the synchronization position obtained when performing the error correction by reproducing, the head position of the packet can be obtained. Packet start position detector 33
Indicates the packet head position information together with the reproduced packet data as P
The data is output to the ID extraction unit 36 and the rearrangement buffer 34.

The PID extractor 36 detects the position of the PID based on the packet head position information, sequentially extracts the PID from a series of packet data, and outputs it to the PID checker 36. As shown in FIG. 6, the PID is transmitted with a 13-bit length from the fourth bit from the next position of the synchronization byte.
The PID extraction unit 36 extracts these 13 bits. When the synchronization byte is not recorded, by outputting a synchronization byte, which is a specific 8-bit code, at the time of output from the output terminal 38, the same as in the case where the synchronization byte is recorded. The result can be obtained. Further, even when information other than the synchronization byte of the packet is recorded after being removed, the position of the PID can be obtained by inputting information according to the synchronization position indicating the delimiter of the packet data.

The PID check section 36 checks whether the extracted PID is a specific PID indicating the head of the special reproduction frame, and supplies the check result to the read address control section 37.
The read address control unit 37 generates a read address of the rearrangement buffer 34 based on the inspection result of the PID inspection unit 36, and supplies the read address to the rearrangement buffer 34.

The rearranging buffer 34 sequentially stores the reproduced packet data from the packet start position detecting section 33 in the order of input, reads the stored reproduced packet data based on the read address from the read address control section 37, and switches the read packet data. The signal is output to 32 terminals b. The switch 32 selects the terminal a during normal reproduction and the forward special reproduction, and outputs the reproduction packet data from the input terminal 31 as it is from the output terminal 38, and selects the terminal b during the reverse special reproduction and rearranges. The packet data from the data buffer 34 is output from the output terminal 38.

Next, the operation of the embodiment configured as described above will be described.

It is assumed that four special reproduction packets can be recorded in one special reproduction data recording area of a magnetic tape (not shown). That is, the 28 pieces of packet data of the first to third special reproduction frames in FIG. 3 can be recorded in seven special reproduction data recording areas T1 to T7. In the trick play data recording area T1, the PAT packet S1, PMT packet S2 and trick play video packets P1, P2 of the first trick play frame of FIG. 3 are recorded, and in the trick play data recording area T2, the trick play video packet P3 is recorded. Or P
Record 6. Similarly, in the special reproduction data recording areas T3 to T7, packets P7 to P9 and S3, packets S4 and P10 to P12, packets P13, P14, S5, and
S6, packets P15 to P18 and packets P19 to P22
Record

Therefore, during reverse special reproduction, packets P19, P20, P21, P22, packets P15, P16, P17,
P18, packet P13, P14, S5, S6, packet S4
, P10, P11, P12, packets P7, P8, P9, S3
, Packets P3, P4, P5, P6, packets S1, S
Reproduction data is obtained in the order of 2, P1, and P2.

These series of reproduced packet data are sequentially supplied to the rearranging buffer 34 via the packet start position detecting section 33 and stored therein. On the other hand, the packet start position detection unit 33 detects the head position of each reproduced packet. P
The ID extracting unit 35 extracts the PID of each packet based on the packet head position information and outputs the extracted PID to the PID checking unit 36. P
The ID checking unit 36 checks whether the PID is 0,
The inspection result is supplied to the read address control unit 37.

For example, when the reproduction packet data S5 is input to the rearrangement buffer 34, the PID inspection unit 36
It checks that D is 0 and outputs an inspection result. Then, the read address control unit 37 generates a read address for outputting the stored data in reverse order every four packets after storing in the reordering buffer 34 up to the next packet of the reproduced packet data S5. That is, the rearrangement buffer 34 first outputs the packet data S5 and S6 recorded in the special reproduction data recording area T5, and then outputs the packet data P15 to P18 recorded in the special reproduction data recording area T6. Output, and then the packet data P19 to P19 recorded in the trick play data recording area T7.
Outputs 22. Thus, the packet data P15 to P22 necessary for decoding the third special reproduction frame can be output to the switch 32.

On the other hand, reproduced packet data S4, P10, P11, and P12 are input to the rearrangement buffer 34, and then reproduced packet data P7, P8, P9, and S3 are sequentially input. When the reproduction packet data S3 is input,
The PID inspection unit 36 outputs an inspection result indicating that the PID is a specific one. As a result, the read address control section 37 outputs the address to the rearrangement buffer 34, and sequentially outputs the stored reproduced packet data S3, S4, P10 to P14. As a result, the packet data P10 to P14 necessary for decoding the second special reproduction frame can be output to the switch 32.

Similarly, the packet data P 1 to P 9 necessary for decoding the first special reproduction frame can be output to the switch 32.

The switch 32 is connected to the terminal b during reverse special reproduction.
And outputs the packet data sequentially input in the frame reverse order via the output terminal 38. By sequentially decoding the packet data from the output terminal 38, the special reproduction image can be displayed in the frame reverse order. At the time of the normal reproduction and the special reproduction in the forward direction, the switch 32 selects the terminal a and outputs the input reproduction packet data as it is.

As described above, in this embodiment, the PID
Is the specific position of the special playback frame by detecting whether or not
34 read addresses are created, and the packet data of each frame can be output in the recording order in the reverse order of the frames. This makes it possible to restore a reversed high-speed playback image without inserting a flag in bucket units or sync block units.

FIG. 5 is an explanatory diagram for explaining another embodiment of the present invention.

In the embodiment shown in FIG. 1, each special reproduction packet is recorded once on a recording medium. However, for example, in the case of performing −8 × speed reproduction, the special reproduction data recording area is traced at an interval of 8 tracks.
Therefore, if each special reproduction packet is recorded once in the special reproduction data recording area, it is necessary to make the tracking phases coincide at eight track intervals. Similarly, for example, -16
In double speed reproduction, it is necessary to match the tracking phases at intervals of 16 tracks.

On the other hand, in a consumer digital VTR or the like, a pilot system capable of on-tracking in a 4-track cycle is employed. Therefore, in the present embodiment, the same special reproduction packet is recorded a plurality of times so that the special reproduction packet can be reproduced at any timing at which on-tracking is possible. FIG. 5 shows an example in which each of the special reproduction packets is recorded twice, corresponding to the case of −8 × speed reproduction. The hatched portion in FIG. 5 indicates a special reproduction data recording area. Also, the solid line in FIG.
, K2,..., And broken lines indicate traceable trajectories K1 ', K2',.

When the same special reproduction data is recorded in two adjacent special reproduction data recording areas with a 4-track interval,
The special reproduction data can be reliably reproduced both in the case where the trace trajectories K1, K2,... Are the obtained tracking phases and in the case where the trace trajectories K1 ', K2',.

In this embodiment, a circuit which is substantially the same as that of the embodiment of FIG. 1 can be used, and a buffer for holding the output of the special reproduction packet creating unit 13 of FIG. The MPX 11 may output the same trick-play packet at a timing corresponding to a plurality of trick-play data recording areas in a 4-track cycle.

Other functions and effects are the same as those of the embodiment of FIG.

The present invention is not limited to the above embodiments. For example, in each of the above embodiments, 0 is selected as a specific PID, but packets having other PIDs are added in units of special reproduction frames. Is also good. In each of the above embodiments, the boundary of each special reproduction image is detected at the time of reproduction by arranging packets of a specific PID immediately before each special reproduction image and recording them. The image may be added and arranged at the end of the image and recorded, or may be arranged and recorded at a specific position. For example, when the packet is added three packets before the packet data sequence, in the special reproduction in the reverse direction, the rearrangement may be performed from the packet three packets after the packet where the specific PID is detected. In this way, by arranging and recording packets of a specific PID at predetermined positions in a packet sequence forming a special reproduction image, a specific PID can be specified during special reproduction.
Can be rearranged for each special reproduction image.

[0072]

As described above, according to the present invention, by recording a packet having a specific packet ID for every predetermined number of packets corresponding to the special reproduction screen, it is possible to determine that the packet is a packet at the boundary between frames. Without recording the information indicating in packet units or sync block units,
There is an effect that data can be restored.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a packet data recording device according to the present invention.

FIG. 2 is a block diagram showing a specific configuration of a special reproduction packet creating unit 13 in FIG. 1;

FIG. 3 is an explanatory diagram for explaining the operation of the embodiment.

FIG. 4 is a block diagram showing a position embodiment of a packet data reproducing apparatus according to the present invention.

FIG. 5 is an explanatory diagram for explaining another embodiment of the present invention.

FIG. 6 is an explanatory diagram for explaining a transport packet of the MPEG standard.

FIG. 7 is an explanatory diagram for explaining packet transmission.

FIG. 8 is an explanatory diagram for explaining a trace locus during special reproduction.

FIG. 9 is an explanatory diagram for explaining recording data to be recorded in a special reproduction data recording area.

FIG. 10 is an explanatory diagram for explaining reproduction data necessary for reverse high-speed reproduction.

[Explanation of symbols]

11 ... MPX, 12 ... DMPX, 13 ... Special reproduction packet creation unit

Continuation of the front page (56) References JP-A-6-261285 (JP, A) JP-A-7-320413 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5 / 91-5/956 G11B 20/10-20/12 H04N 7/24-7/68 H04N 5/782-5/783

Claims (7)

(57) [Claims] 1. A special reproduction data created by creating a special reproduction data from an input packet data string in which a plurality of types of data are created by time division multiplexing in a predetermined packet unit and a packet ID indicating the type is inserted for each packet. A special reproduction data packetizing means for converting the reproduction data into the packet unit and outputting the packet; and displaying the packet having a specific packet ID in order to indicate a boundary between the special reproduction screens corresponding to the special reproduction data. Specific packet insertion means for creating a special reproduction packet by inserting every predetermined number of packets corresponding to each of the special reproduction screens output from the data packetizing means; and recording special reproduction data at a predetermined position of a track formed on a magnetic tape Recording means for recording the trick play packet in an area. 2. The apparatus according to claim 2, wherein said specific packet inserting means comprises: a position detecting means for detecting a boundary position between a predetermined number of packets corresponding to each of said special reproduction screens; 2. The packet data recording apparatus according to claim 1, further comprising multiplexing means for arranging a packet having the specific packet ID at a position. 3. The multiplexing unit stores a packet having a specific packet ID separated from the input packet data sequence, and stores the packet in the storage unit according to a boundary position detected by the position detection unit. 3. The packet data recording apparatus according to claim 2, further comprising: a reading unit that reads a packet that has been read. 4. The packet according to claim 2, wherein the multiplexing unit arranges packets having the specific packet ID immediately before or immediately after a predetermined number of packets corresponding to each of the special reproduction screens. Data recording device. 5. A packet for reproducing the magnetic tape recorded by the packet data recording apparatus according to claim 1, wherein the packet having the specific packet ID is obtained from reproduction data obtained by reproducing the magnetic tape. Packet data reproducing means for detecting packet data, and rearranging means for rearranging the reproduced data in packet units based on a detection result of the specific packet detecting means during reverse high-speed reproduction. apparatus. 6. The specific packet detecting means includes: a head position detecting means for detecting a head position of each packet from the reproduction data; and inserting a packet ID of each packet based on the head position detected by the head position detecting means. 6. The packet data reproducing apparatus according to claim 5 , further comprising identification means for detecting a position to identify whether or not the packet has the specific packet ID. 7. The rearrangement means stores reproduction data in packet units, and reverses a series of the special reproduction screens based on a detection result of the specific packet detection means and corresponds to each of the special reproduction screens. 6. The packet data reproducing apparatus according to claim 5 , further comprising storage means for outputting a predetermined number of packets to be arranged in a recording order.