JPH0319589A - Video signal reproducing device - Google Patents

Abstract

PURPOSE:To facilitate succeeding data processing by providing a sequence conversion means replacing the sequence of a reproduced identification information and a video signal in the unit of recording areas and operating the sequence conversion means at the reverse reproduction to reproduce the video signal in the similar sequence to the forward reproduction. CONSTITUTION:A sequence conversion means 23 is provided, which replaces the sequence of the reproduced identification information and video signal in the unit of recording areas when the identification information and video signal are reproduced from a recording medium 2 having a border of the identification information to identify the storage area in the center of a track and recorded with the identification information and video signal in the recording area for each recording area, the sequence conversion means 23 is operated at the reverse reproduction. Thus, the sequence of the identification information and video signal reproduced at the reverse reproduction is similar to that at the forward reproduction and the reproduced data is processed similarly at the forward reproduction and the data processing of the post-stage is facilitated.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to a digital video tape recorder (digital VT recorder) using a D-1 format video tape, for example.
The present invention relates to a video signal reproducing device suitable for use in R).

(Summary of the Invention) The present invention relates to a video signal reproducing device suitable for use in a digital VTR using, for example, a D-1 format videotape, in which a boundary of identification information for identifying a recording area in the center of a track is provided. In a video signal reproducing device that reproduces identification information and a video signal from a recording medium which has a recording area in which a video signal is recorded together with identification information of this recording area, the order of the reproduced identification information and video signal is recorded. By providing an order converting means for permuting areas, and operating the order converting means during reverse playback, subsequent data processing becomes easier and the memory capacity for the reproduced video signal can be reduced. It is something.

(Prior art) When recording a large amount of information like in a digital VTR, it is difficult to record one field of video signal on one track, so one field of video signal is recorded on multiple tracks. In this case, alternating tracing of these tracks with a pair of recording or reproducing heads installed on a rotary head would impose too much burden on the processing speed of the data obtained. The two channels of magnetic heads are scanned in parallel in each trace.Also, in order to perform noiseless playback over a wide speed range in digital VTRs, dynamic tracking technology developed for analog VTRs is being applied. be.

FIG. 7 shows a rotary head for a conventional digital VTR capable of dynamic tracking.
(1) is a rotating head, (2) is a videotape transferred in the forward direction (v direction), R (A) to R (D) are recording heads, respectively, and P (A) to P (D) are respectively The reproducing heads (3) and (4) are bimorph elements each supporting a pair of reproducing heads. Note that hereinafter, the symbols A to D indicate the reproduction heads, respectively. When the rotary head (1) rotates at a rotation speed ω, the action of the bimorph elements (3) and (4) causes a pair of reproducing heads A, B and a pair of reproducing heads C, D to rotate in the θ1 direction and in the θ1 direction, respectively. It is said that it can be freely displaced within a predetermined range in the θ2 direction. Furthermore, the I)-1 format, which is an international standard, is widely used as a videotape format for digital VTRs. In this D-1 format, video and audio signals for one field of the NTSC system (525/60 system) are recorded in a curved manner distributed over 10 tracks, as shown in Figure 8A. The track consists of a part of the audio sector (2b) containing the time code located in the center and two tracks that sandwich this part of the audio sector (2b).
video sectors for video signals (2a), (2c
). The reason why the audio sector part (2b) is placed in the center is that the error rate of audio data needs to be lower than that of video data. Furthermore,
The 10 tracks are divided into 5 segments of 2 tracks each (
The screen is divided into segment numbers 0 to 4), and each segment 0 to 4 has 50 lines formed by dividing the L field screen (5a), (5b), and (5c) into 5 equal parts as shown in Figure 9. A video signal of horizontal scanning lines is recorded. Each segment O to 4 has four sectors (
Each sector is identified by an ID address (identification address) defined as follows.

ID address = (Sector number 1, segment number (field number)) Sector number 1 = 0 to 3 Segment number 10 to 4 Field number = 0 to 3 (2 bits) However, as a field number, the number of the least significant bit is O indicates an even field, 1 indicates an odd field, and the second bit of the regular field number is used as the frame number.

As shown in FIG. 8B, each video sector consists of a preamble containing a synchronization pattern and an ID pattern, 160 synchronization blocks, and a postampule (not shown), and each synchronization block has a synchronization pattern and an ID pattern added to it. , the ■D pattern includes ID address information as shown in FIG. 8C. Furthermore, for example, P
In the AL system (625/50 system), video signals for 1 field are distributed and recorded on 12 trunks, so the segment numbers are 0 to 5.

The operation when playing back at +1x speed in the forward direction using the rotary head of the example shown in FIG. 7 will be explained with reference to FIG. 10. In this case, the video tape (2) is However, in the drawing, the tape (2) is stationary and the playback heads A, B and 1! Jl's playback heads C and D do not trace the tape■. Display as if moving in the opposite direction. It is also assumed that in the initial state, the reproducing heads A and B are located at tracks 1 and 2 of field O, respectively, and that the reproducing heads thereafter move to tracks 3, 4, 5, 6, . . . . At this time, field numbers in the ID address are extracted from the playback data output from each playback head, and FIG. 11 shows the field numbers arranged along the time axis. As is clear from FIG. 11, in the case of forward playback, the field number of the playback data increases monotonically, and there is no problem in subsequent data processing.

Next, using the rotating head shown in FIG.
The operation when performing reproduction at double speed will be explained with reference to FIG. 12. In FIG. 12, the reproduction head A. B starts tracing from tracks 17, I8 of field 2 in the initial state, and each playback head thereafter traces tracks 16, 15, 14, . Assume that it moves as 13... This method of reproducing one field of data from the last track to the first track during reverse playback is known from Japanese Patent Application Laid-Open No. 61-150 published by the present applicant.
It is disclosed in Japanese Patent No. 476. Further, a part of the trajectory of the reproducing head when the dynamic tracking operation is not performed is shown by a broken line, and the actual trajectory of the reproducing head due to the dynamic tracking operation is shown by a solid line. Playback hend A,
Regarding B, the deviation in the direction of arrow (6a) is the regeneration hand C.
, D are given deviations in the direction of arrow (6b), respectively. At this time, the field numbers extracted from the playback data output from each playback head are arranged along the time axis as shown in Fig. 13. From this figure, it can be seen that the field numbers of the playback data are monotonous during reverse direction playback. It can be seen that the value does not decrease to 1, but is reversed at the boundary of each field.

Furthermore, as the initial phases of the playback heads A and B shift in the direction of arrow (7) or arrow (8) in FIG.
The pattern in FIG. 13 varies in various ways.

Similarly, when playing back at -0.75 times speed using the rotary head shown in the example in Figure 7, the pattern in which the field numbers of the playback data obtained from each playback head are arranged along the time axis is There are various patterns as shown in FIG. 14A-H.

Furthermore, as a digital VTR that is an improvement over the example shown in FIG. 7, the present applicant proposed a digital VTR having a rotary head (1) as shown in FIG. 16 in Japanese Patent Application No. 63-261860. In FIG. 16, the recording head is the same as the conventional one, but the number of reproducing heads supported by bimorph elements (3) and (4) is four (P(AI).P(81)).
, P(Cz), p(ox) and P(c+), P
(DI). P(A2), P(B.)). Simply use these playback heads as A1-D! ,Cl~B
2, four playback heads AI, Bl, Ct. D.I.
trace the tape in parallel and synchronized, but with a 180° phase delay? 4 playback heads C. ,D
I+A■B trace the tape in parallel.

Figures 17 to 19 show the state of reproduced data when, for example, reproduction is performed at -1x speed using the rotary head shown in Figure 16.
To explain with reference to the figure, it is assumed that data is reproduced in the reverse order from field 10 (=2) of the videotape to field 01, field OO, and field 11 (=3) as shown in FIG. do. Note that the field number is a 2-bit number, and strictly speaking, fields 00 to 11 (0 to 3) can be identified as described above, but in this example, the lower 1 bit is used to indicate that the field is an even field. Suppose we only want to identify whether a field is an odd field or an odd field.

Furthermore, although the video tape is transferred in the reverse direction (V direction), FIG. Each sector is assigned a certain ID address based on the segment number O to 4 and the field number O or l. Furthermore, the data reproduced from the sector having the ID address is also identified by attaching the ID address.

In this case, as shown in FIG. 17, the playback heads A1, Bx
, Cz-Dt are sectors 4 (1) and 4 (1), respectively.
, O (0) Assuming we start the trace from 0(0), then the playhead C + , D + , A
Trace is performed from the position where z, B t is shifted by 2 trasok, and then the playback head is moved again to Az+B++Cz
Since +Dz is traced from a position further shifted by two tracks, the data reproduced from each reproduction head is arranged on the time axis as shown in FIG. 18. And field 1001. It is assumed that the data reproduced from 00 is recorded into three field memories for each segment.

As is clear from FIGS. 17 and 18, in the case of this multi-head system, not only the field number but also the segment number always undergoes a reversal phenomenon.

Similarly, using the rotary head shown in Fig. L6, 10,75
FIG. 19 shows how the ID address changes when playing back at double speed. In this way, at -0.75x speed, the ID
Addresses vary in an extremely complex manner.

[Problem to be solved by the invention]

As mentioned above, when performing reverse playback using a D-1 format video tape, a reversal phenomenon occurs in the field numbers and segment numbers of the playback data output from each playback head, making it difficult to process the data later. This has the disadvantage of complicating the process.

Specifically, in digital VTRs, the data itself undergoes complicated shuffling to prevent errors, so if a reversal phenomenon occurs in the field numbers, etc. of the playback data, an error will occur in the repopulated data. In some cases, it may be determined that the error has occurred, and a complicated processing program is required to further suppress the occurrence of this error.

Also, in reverse slow playback, frame-by-frame images without noise are required, but in order to achieve this, usually multiple (for example, three) field memories are provided, and one of these field memories is A method is adopted in which when enough image data has been written into a field memory, the field memory is switched to the next field memory.

However, in the prior art, the above-mentioned reversal phenomenon of the reproduced field numbers occurs, which adversely affects the determination of field memory switching. That is, after detecting a new field number, determining that all the image data of the previous field has been reproduced, and specifying the field memory number to be written next, the image data of the previous field is input. If the image data of different fields is mixed into one field memory, errors such as erroneous corrections occur.

For example, if playback is being performed at -0.75 times the speed and the field' number pattern of the data played back from each playback head is as shown in Figure 15A, three field memories A, B, and C are used. Let's consider the case of inputting and outputting image data using In this case, as shown in FIG. 15B, image data corresponding to reproduced field numbers 2, 1, and O, respectively, are sequentially written into field memories A, B, and C. And these field memories A and B
, C, the image data is sequentially read from the unwritten field memory at a cycle of one field period ■, and the read image data is converted into digital/analog (D
/A) Supplied to the monitor via a converter.

For example, when image data is successively read out in the order of field memory C → field memory A → field memory B at the timing shown in FIG. There is no particular inconvenience. However, while operating the search dial etc. to perform variable speed playback, -
When the speed is increased to 0.75 times, reading from field memories A, B, and C is performed periodically in l field period ■, whereas the phase of the reproduced image data is It is not fixed and can take various cases.

Therefore, when the field memory for writing (FIG. 15B) is used as a reference, the phase of the field memory for reading may vary as shown in FIGS. 15D and 15 in addition to FIG. 15C.

In this case, the image data of field number l has a reversal phenomenon occurring on both sides, and the field number 1, which is stable, becomes smaller than V, which is one field period. Therefore, for example, the period (9) and the period (1) of FIG.
As shown in period (10) in Figure 5E, so-called address overtaking may occur in which data is written to the field memory that is being read. This indicates that in the prior art, three field memories are not enough to accurately process reproduced data, and four field memories are required.

In view of the above, the present invention has been developed to facilitate subsequent data processing and to ensure that even if a reversal phenomenon of identification information such as an ID address occurs during reversal playback in a D-1 format digital VTR, etc. The purpose is to reduce the capacity of signal memory.

[Means for Solving the Problem] As shown in FIG. 1, for example, the video signal reproducing apparatus according to the present invention has identification information (for example, segment number, field number, frame number) for identifying the storage area in the center of the track. A video signal that reproduces the identification information and the video signal from a recording medium (for example, a D-1 format video tape (2)) that has a boundary between the recording areas and the identification information of this recording area and the video signal. The reproducing device is provided with an order converting means (23) for changing the order of the reproduced identification information and video signal in units of recording areas, and the order converting means (23) is operated during reverse playback. be.

[Effect]

According to the present invention, during reverse playback, the reproduced identification information and the order of the video signal are the same as during forward playback. Therefore, the reproduced data can be processed in the same way as during forward reproduction, making subsequent data processing easier.

Furthermore, since the inversion phenomenon of identification information is eliminated at the data processing stage, the memory capacity for reproduced video signals can be reduced. [Embodiment] Hereinafter, an embodiment of a video signal reproducing apparatus according to the present invention will be described with reference to FIGS. 1 to 4.

In this example, the present invention is applied to a digital VTR using a D-1 format videotape. Further, as the rotary head in this example, the multi-head dynamic tracking type rotary head shown in the example in FIG. 16 is used as is.

FIG. 1 shows a playback device for one channel of the digital VTR of this example, and in this FIG. 1, one playback head (20) out of eight playback heads attached to a rotary head
The reproduced data is transferred to P for pit clock reproduction.
Convert to input data DX via L L (21),
This input data DX is written to a predetermined address in the memory (22). The pattern of this input data DX is a series of tracks in the D-1 format as shown in FIG. 2A (for example, tracks 18, 17, 16, 15, etc. in FIG. 12).
), the data of a pair of video sectors al.
The audio sector data is inserted between bl, etc. Further, the memory (22) may be a working memory or the like, and may also be used as a time base collector memory or the like.

(23) indicates an address conversion circuit, which generates read addresses in the same order as write addresses during forward playback and supplies them to the memory (22), and during reverse playback, one track is generated. The addresses obtained by exchanging the write addresses for the data of the pair of video sectors for each of the data corresponding to are supplied to the memory (22) as read addresses. Further, the output data DY read from the memory (22>) is supplied to the extraction circuit (24), and the extraction circuit (24) extracts the synchronization signal (SYNC) and ID address. The image data and ID address are written into a predetermined area of the field memory (26) via the inner code correction circuit (25). Code correction circuit (27) and error correction circuit (28)
This error correction circuit (28
) is supplied to the monitor (30) via the D/A converter (29). In this example, assuming that the field memory (26) has a storage capacity of three fields for all eight playback heads, these logically identified field memories are respectively field memory A and field memory A, respectively.
They are called B and C.

The operation when performing reverse playback in the example of FIG. 1 will be described with reference to FIGS. 2 to 4. During reverse playback, the address conversion circuit (23) performs an address conversion operation. Therefore, the input data DX written in the memory (22) in the pattern shown in FIG. 2A is converted into the pattern shown in FIG. 2B at the time of reading and is read out as output data DY.

For example, if we focus on the field numbers in the playback data output from each playback head when playback is performed at -0.75x speed, in the conventional example, as shown in Figure 14A-E, the field number is at the boundary of the field. A reversal phenomenon is occurring. However, in this example, since the playback data is rearranged around the audio sector, the field numbers in the playback data output from each playback head are as shown in Figure 3A-H, and no reversal phenomenon occurs. .

Therefore, this example has the advantage that subsequent data processing is extremely easy.

Also, if the field number pattern in the playback data is the fourth
In the case of the pattern shown in FIG. 4A, for example, the image data of field numbers 2 and 1.0 are sequentially written into the field memories A and BC as shown in FIG. 4H. In this case, when the speed becomes -0.75 times during variable speed playback using the search dial, the writing timing changes variously, but from the field memories AB and C. The data is read in l field period V
This is done periodically at all times. Therefore, based on the write timing (FIG. 4B), the read timing of data from field memories A, B, and C is based on the fourth timing.
Various cases may occur as shown in Figures CE.

However, in this example, since no field number reversal phenomenon occurs, the reproduced field number shown in FIG. 48 is stable for approximately one field period (2) at least in the range of -1 times speed to 0 times speed. Therefore, unlike the conventional example, it is possible to avoid erroneously writing to a field memory that is being read continuously, and there is an advantage that noiseless playback can be performed up to approximately -1 times the speed using only three field memories.

Next, another embodiment of the present invention will be described with reference to FIGS. 5 and 6. In this embodiment as well, a multi-head dynamic tracking type rotary head shown in FIG. 16 is used.

In this example, during reverse playback, each playback head follows a curved path along the solid line (32) as shown in FIG.
Dyna-dan vine tracking is performed to trace the trunk of a 1-format videotape. For example, at -0.75x speed, when dynamic tracking is not working, each playback head is displaced along a path along the broken line (33), so the bimorph element applies displacement in the direction of arrow (34) to each playback head. There is a need.

In this case, playback heads A, . B. ,C. , D, have initial phases of 1 (1), 1 (1), 2 (1), respectively.
2 Assuming (1), the pattern in which the ID addresses in the playback data output from the node for each playback are arranged along the time axis is as shown in FIG. As is clear from FIGS. 5 and 6, no reversal phenomenon occurs in the field numbers output from each reproducing head. Therefore, in the case of the example shown in FIG. 5, the order changing means for changing the order of the reproduced signals is the dynamic tracking mechanism itself, but the operation and effect are the same as in the example shown in FIG.

In the example shown in FIG. 1, the memory (22) may be provided at any position within the range X in FIG. Furthermore, the present invention can also be applied to a digital VTR using a rotating head with a small number of playback heads as shown in the example of FIG. As described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various configurations may be adopted without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, even when the video signal is played back in the reverse direction, the video signal is played back in the same order as when it is played back in the forward direction, so there is an advantage that subsequent data processing becomes easier.

Furthermore, since the reversal phenomenon of the identification information in the data processing section is eliminated and the period during which the video signals of each recording area are reproduced is equalized, there is an advantage that the video signals can be sequentially stored in a memory with a small storage capacity.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing one embodiment of the present invention, Figures 2 to 4
The drawings are diagrams for explaining the operation of the example shown in FIG. 1, FIGS. 5 and 6 are diagrams for explaining other embodiments of the present invention, and FIG. 7 is a plan view showing a conventional rotary hand. Figures 8 and 9 are diagrams for explaining the D-1 format, respectively.
Figures 10 to 15 are diagrams for explaining the example in Figure 7, Figure 16 is a plan view showing the rotary head of the earlier application, and Figures 17 to 19 are diagrams for explaining the example in Figure 16, respectively. FIG. (2) is a D-1 format video tape, (3) and (4) are bimorph elements, (20) is a playback head, (22) is a memory, (23) is an address conversion circuit, (
26) is field memory. Agent Hidemori Matsukuma? c To the rotation of the masu・Y' Fig. 18

Claims (1)

[Scope of Claims] The identification information and the video signal are obtained from a recording medium that has a boundary of identification information for identifying the recording area in the center of the track, and in each recording area, the identification information of the recording area and a video signal are recorded. A video signal reproducing device for reproducing a video signal, characterized in that an order converting means is provided for changing the order of the reproduced identification information and the video signal in units of the recording areas, and the order converting means is operated during reverse playback. Video signal reproducing device.