JPH07110060B2 - Recording / playback device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus adapted to record / reproduce still image information in the form of digital signals using a magnetic tape.

2. Description of the Related Art As one of conventional recording / reproducing apparatuses, a digital signal is used that converts an audio signal into a digital signal and records it on a magnetic tape, and also converts a digital signal recorded on the magnetic tape into an audio signal for reproduction.・ Audio tape recorder (Di
gital Audio Tape recorder; hereinafter referred to as DAT) is well known. In the case of this DAT, when audio signals are converted to digital signals and recorded on a magnetic tape, information for error correction can also be recorded at the same time, so even if some of the recorded information is lost, it can be restored. Therefore, not only the original sound can be reproduced faithfully, but also the sound with less noise can be reproduced.

By the way, in the above-mentioned conventional DAT, a two-channel mode in which two channels for individually recording two types of audio signals are set in a magnetic tape as an operation mode, and four types of audio signals are individually controlled. There is one that allows selection of a four-channel mode in which four channels for recording are set on a magnetic tape. Among them, in the 2-channel mode, two types of audio signals corresponding to the two speakers arranged on the front left side and the front right side of the listener are recorded on the magnetic tape, and in the 4-channel mode, the front side of the listener is detected. Four types of audio signals corresponding to four speakers arranged on the left side, the front right side, the rear left side, and the rear right side are recorded.

In the case of the 4-channel mode, 2 of them
A system in which an audio signal is recorded in each channel and a still image video signal is recorded in each of the other two channels and the audio signal and the video signal are simultaneously reproduced from one magnetic tape is also known. . In the case of this method, a still image video signal for one screen is recorded on the magnetic tape by assigning a plurality of tracks as one unit, and in the reproducing operation, reproduction is started from the stop position of the magnetic tape.

However, in the case of the above-mentioned conventional DAT, when the reproduction operation is once stopped and then reproduced again, for example, a recording area in which a still image video signal for one screen is recorded on the magnetic tape. The reproduction may be started in the middle of, and at this time, the still image can be reproduced only in the form in which a part of one screen is missing.

Further, when the recording operation is started after the reproduction operation is once stopped, the recording of a new still image video signal is started in the middle of the recording area in which the still image video signal for one screen is recorded, and the old operation is performed. The still image video signal may be destroyed due to the newly recorded still image video signal, and it is difficult to replace the old still image video signal with a new still image video signal in a unit of one screen. It was

Therefore, an object of the present invention is a recording / reproducing apparatus adapted to record / reproduce still image information as a digital signal using a magnetic tape, and when reproducing or recording after temporarily stopping the reproducing operation, An object of the present invention is to provide a recording / reproducing apparatus in which a still image partially lacking is not reproduced and still image information recording is not incomplete.

Means for Solving the Problems According to the present invention, still image information as a digital signal is sequentially recorded in a plurality of continuous areas on a magnetic tape in units of one screen, and a still image for one adjacent screen is recorded. In a recording / reproducing apparatus in which a non-recording area in which still picture information is not recorded is provided between recording areas in which information is recorded, at the time of recording, it is discriminated whether or not the still picture information is recorded in each area of the magnetic tape. And a sub-signal recording means for recording a sub-signal for reading the sub-signal from the magnetic tape at the time of reproducing and rewinding, and based on the sub-signal, the reproducing position of the recording / reproducing head is in the recording area of the magnetic tape. Discriminating means for discriminating whether or not it is in the non-recording area, and controlling the running of the magnetic tape based on the discrimination result by the discriminating means in response to a temporary stop command during reproduction, and recording / reproducing When the reproducing position of the head is in the recording area, the magnetic tape is run in the rewinding direction, and the discriminating means detects that the reproducing position of the recording / reproducing head has reached the non-recording area. The recording / reproducing apparatus is provided with a temporary stopping means for stopping the running of the magnetic tape.

Operation According to the present invention, when the reproduction position of the recording / reproducing head when the reproduction is temporarily stopped is in the middle of the recording area of the still image information for one screen, the recording area for the still image information, The magnetic tape is rewound and stopped until the recording / reproducing head corresponds to a non-recording area which is not recorded between the adjacent recording area of the still image information. Therefore, when the reproduction operation is restarted next, one screen of still image is reproduced without omission. Even when the recording operation is started after the reproduction operation is temporarily stopped, all the recorded contents of the recording area for one screen of the old still image information is replaced with the new still image information. The record will never be left incomplete.

Embodiment FIG. 1 is a block diagram showing a schematic configuration of a recording / reproducing apparatus which is an embodiment of the present invention.

This recording / reproducing apparatus is a DAT capable of selecting the above-mentioned four-channel mode as an operation state, and two channels out of the four channels are for recording and reproducing two kinds of audio signals and the remaining two channels. Are assigned for recording and reproducing still image signals.

In FIG. 1, an input terminal TR is a terminal for inputting one kind of audio signal, and the audio signal in this case is, for example, an audio signal to be output from a speaker arranged on the front right side of the listener. Is. The other input terminal TL is a terminal for inputting another type of audio signal, and the audio signal in this case is, for example, an audio signal to be output from a speaker arranged on the front left side with respect to the listener. is there. Still another input terminal TV is a terminal for inputting a video signal of a still image. These input terminals TR, TL, TV are connected to corresponding analog-digital (hereinafter referred to as A / D) conversion circuits 1, 2, 6, respectively.

The A / D conversion circuits 1 and 2 have a function of converting audio signals input from the corresponding input terminals TR and TL into, for example, 12-bit digital audio signals D1 and D2. The output terminals of the A / D conversion circuits 1 and 2 are connected to the input terminals 51 and 52 of the changeover switch 5 via lines 3 and 4, respectively.

The A / D conversion circuit 6 has a function of converting the video signal input from the corresponding input terminal TV into, for example, an 8-bit digital video signal D3. The output terminal of the A / D conversion circuit 6 is connected to the data bus 7.

An image memory 8a is connected to the data bus 7. The image memory 8a is a memory for taking in the digital video signal D3 for one screen output from the A / D conversion circuit 6 via the data bus 7 and recording it.

A parallel-serial (hereinafter referred to as P / S) conversion circuit 9 is separately connected to the data bus 7. This P / S
The conversion circuit 9 has a function of taking in an 8-bit digital video signal read from the image memory 8a via the data bus 7, converting this into a serial signal from a parallel signal, and outputting it. The output terminal of the P / S conversion circuit 9 is connected to the input terminal 53 of the changeover switch 5.

The change-over switch 5 has a function of selectively applying a digital signal derived to each of the input terminals 51 to 53 to the output terminal 54, and the output terminal 54 is connected to the recording signal processing section 11 of the next stage. .

The recording signal processing unit 11 has a modulation function of modulating an input digital signal, a sub information adding function of adding error correction and other sub information to the input digital signal, and the like. The signal processed at 11 is recorded on the magnetic tape 12. In the case where the above-mentioned audio signal is music, for example, as a sub-signal added by the sub-information adding function, a start ID indicating the beginning of a song, an end ID indicating the end of the recording area on the magnetic tape 12, and the like. Sub-information called control ID, sub-information called pack data indicating total time that is the required playback time from the beginning of the magnetic tape 12 to each halfway and song time that is the required playback time for each song are generated. .

In the case of this embodiment, the recording signal processing section 11 generates back data in the format shown in Table 1 below as one of the sub information added to the digital signal.

Upper 4 bits B7 to B of the first byte PC1 of them
In 4, a back item, which is a code for identifying the content of the back data, is written. For example, when this pack item (pack item) is "0001", the content of the pack data is the song time. "0010" indicates that the content of the pack data is the total time, and "1110" indicates that the content of the pack data is a still image page.

An identification code ID1 indicating whether or not the recording area of the pack data in the recording area of the magnetic tape 12 is an area in which still image information (digital video signal) is recorded is written in the bit B3 of the byte PC1. For example, when the identification code ID1 is 1, it indicates a still image information recording area, and when the identification code ID1 is 0, it indicates a still image information unrecorded area. Same byte PC1
An identification code ID2 indicating whether or not the recording area of the pack data in the recording area of the magnetic tape 12 is the head of the still image information recording area for one screen is written in the bit B2 of the portion of, for example, still image information. ID2 = 1 is written in the first 10 tracks of the recording area.

Bytes PC2 and PC3 of pack data shown in Table 1 above and below each 4
Bits B7 to B4 and B3 to B0 are the BCD that indicates the number of pages of the still image.
The 4-digit page identification code PAGE1 to PAGE4 is written.
Furthermore, as shown in Table 1, pack parity, which is data for error correction of the pack data, is written in the last byte PC8 of each pack data.

In FIG. 1, the reproduction signal processing unit 13 has a demodulation function for demodulating the signal read from the magnetic tape 12, a processing function for performing processing such as error correction from the read sub-signal, and outputs the same. Terminal is changeover switch 15 via line 14
Connected to the input terminal 154 of the. This playback signal processing unit 1
The processing function of 3 indicates that when the pack data described above that is reproduced when an instruction to stop the reproduction operation is given from the outside is in the middle of the still image information recording area, the magnetic tape 12 A function of outputting a command for rewinding to the position immediately before the beginning of the still image information recording area is included.

The changeover switch 15 has output terminals 151, 152, 153,
It has a function of selectively giving a digital signal derived from the reproduction signal processing unit 13 to the input terminal 154 via the line 14 to each of the output terminals 151 to 153. Among them, the output terminals 151 and 152 are connected to the corresponding digital-analog (hereinafter referred to as D / A) conversion circuits 16 and 17, respectively.

The D / A conversion circuits 16 and 17 are output terminals 151 and 152 of the changeover switch 15.
It has the function of converting the digital signal derived in to the analog signal. The output terminals of the D / A conversion circuits 16 and 17 are connected to the corresponding output terminals TR1 and TL1, respectively.

The other output terminal 153 of the changeover switch 15 is connected to the serial-parallel (hereinafter referred to as S / P) conversion circuit 18. The S / P conversion circuit 18 has a function of converting the digital signal derived at the output terminal 153 of the changeover switch 15 into, for example, an 8-bit parallel signal and outputting the parallel signal. The output terminal of the S / P conversion circuit 18 is connected to the data bus 7.

An image memory 8b different from the image memory 8a described above is connected to the data bus 7. These two image memories 8a and 8b serve to store digital signals output from the S / P conversion circuit 18 during reproduction.

Further, another D / A conversion circuit 19 is connected to the data bus 7. The D / A conversion circuit 19 has a function of converting a digital signal read from the image memories 8a and 8b during reproduction into an analog signal. The output terminal of the D / A conversion circuit 19 is connected to the output terminal TV1.

FIG. 2 is a plan view schematically showing a part of the magnetic tape 12 on which the digital video signal is recorded by the DAT, and FIG. 3 is a recording area of the magnetic tape 12 and Table 1. It is explanatory drawing which shows the correspondence with the value of identification code ID1, ID2 of pack data. Each operation of recording and reproducing the DAT will be described below with reference to FIGS. 2 and 3.

An audio signal corresponding to the front right speaker is input to the recording input terminal TR, and an audio signal corresponding to the front left speaker is input to the input terminal TL. further,
A video signal of a still image is input to the input terminal TV. The audio signals input from the input terminals TR and TL are, for example, 12-bit digital audio signals D by the A / D conversion circuits 1 and 2, respectively.
It is converted to 1, D2 and is output as a serial signal on lines 3 and 4. The digital audio signals D1 and D2 derived on the lines 3 and 4 are given to the input terminals 51 and 52 of the changeover switch 5, respectively.

The video signal input from the input terminal TV is converted into, for example, an 8-bit digital video signal D3 in the A / D conversion circuit 6 and given to the data bus 7 as a parallel signal. This digital video signal D3 is transferred from the data bus 7 to the image memory 8a.
Given to. In the A / D conversion circuit 6, the input video signal is sampled at a sampling frequency of 14.3 MHz and converted into a digital signal. The digital video signal D3 corresponding to the video signal for one still image thus obtained is stored in the image memory 8a in 1/60 sec. When the writing of the digital video signal D3 corresponding to the video signal for one screen to the image memory 8a is completed, the stored digital video signal is transferred from the data bus 7 to the P / S conversion circuit 9
Is supplied to the input terminal 53 of the changeover switch 5 as a serial signal from the P / S conversion circuit 9.

The output terminal 54 of the change-over switch 5 is selectively supplied with a digital signal derived from the input terminals 51 to 53, and such a digital signal is supplied from the line 10 to the recording signal processing unit 11. In the recording signal processing unit 11, data and other sub-signals for error correction with respect to the input digital processing are added to each digital signal, signal processing such as modulation is performed, and then recorded on the magnetic tape 12. .

At the time of recording, a video signal for one screen of a still image is recorded on the magnetic tape 12 shown in FIG. 2 as a unit of a plurality of tracks shown by hatching on the upper right, and still image signals for a plurality of screens are sequentially recorded. .

In FIG. 2, an arrow T indicates the direction of recording / reproduction on the magnetic tape 12, and the N-1 and N areas are recorded with the video signals of the N-1th and Nth still images, respectively. Indicates. An area A interposed between the areas N-1 and N indicates an area in which a video signal of a still image is not recorded. In addition, the recording area D of the above-described sub-signal (the broken line area shown in FIG. 2) is set in each track.

Therefore, in the pack data recorded in the recording area D in the areas N-1 and N, the page numbers are N-1 and N, respectively.
Has become. The recording area D in the areas N-1 and N
The identification code ID1 = 1 in the pack data recorded in No. 1 and ID1 = 0 in the pack data in the area A.
Has become. Further, in the area B from the beginning to the 10th track in the area N, that is, in the area in which the vertical hatching is overlapped with the upper right hatching in FIG. 2, the identification code ID2 of the pack data is 1 and the other tracks. Then, the identification code ID2 of the pack data is 0.

During reproduction and reproduction, the signal read from the magnetic tape 12 is input to the reproduction signal processing unit 13. The reproduction signal processing unit 13 performs demodulation and error correction processing based on the reproduction sub-signal, and the digital signal subjected to such signal processing is given from the line 14 to the input terminal 154 of the changeover switch 15.
The changeover switch 15 has output terminals 151, 152, 153,
Digital signals corresponding to the audio signals input from the input terminals TR and TL are derived at the output terminals 151 and 152, and the derived digital signals are converted into analog signals by the D / A conversion circuits 16 and 17, respectively, It is led to the output terminals TR1 and TL1.

A digital signal corresponding to the video signal input from the input terminal TV is derived from the output terminal 153 of the changeover switch 15, and the derived digital signal is given to the S / P conversion circuit 18.
For example, it is given to the data bus 7 as a parallel signal of 8 bits each. This digital signal is given to either one of the image memories 8a and 8b connected to the data bus 7.

A digital video signal is supplied to the D / A conversion circuit 19 via the data bus 7 from the image memory of one of the image memories 8a and 8b in which the storage of the digital video signal has been completed. This digital video signal is converted into an analog signal by the D / A conversion circuit 19 and led to the output terminal TV1.

Writing of the digital video signal to the image memories 8a and 8b is performed to one of the image memories, and at this time, the digital video signal stored in the other image memory is given to the D / A conversion circuit 19. ing. When the writing operation of the digital video signal to the one image memory is completed, that is, the writing of the digital video signal for one screen is completed, the D / A conversion circuit 19 is provided with the output of the one image memory. Become. At this time, writing of the digital video signal from the S / P conversion circuit 18 is started in the other image memory. In this way, the D / A conversion circuit 1
The outputs of the image memories 8a and 8b are alternately given to 9, and the display of a still image thus changing at a certain fixed time can be performed by a display device such as a CRT (cathode ray tube). .

The sampling frequency in the A / D conversion circuits 1 and 2 is, for example,
It is set to 32 KHz. The audio signals input from the input terminals TR and TL correspond to, for example, the front right and left speakers of the listener. Two channels are assigned to the video signal input from the input terminal TV. Correspondingly, in the changeover switch 5, the output terminal 54 and the input terminals 51, 52, 53 are sequentially connected.

The changeover operation of the changeover switch 5 is performed corresponding to, for example, the sampling signal having the above-mentioned frequency, and the input terminal 51 is selected during the period of 1/4 of the period of one period of the sampling signal, and is followed by this. The input terminal 52 is selected during the period of 1/4 cycle, and the input terminal 53 is selected during the period of the following half cycle to establish electrical connection with the output terminal 54. In this way, the 12 × 4 bit digital signal is input to the recording signal processing unit 11 during the period of one cycle of the sampling signal.

Since the image memory 8a must store a digital video signal corresponding to one screen of still video, for example, the output of the A / D conversion circuit 3 for one field period, that is, 1/60 sec period is stored. You must be able to. Therefore, the storage capacity of the image memory 8a is 14.3 (MHz) x 8 (bits) x 1/60 (sec) = 1.911 (M bits) (1).

The digital video signal read from the image memory 8a to the recording signal processing unit 11 is 32 (KHz) × 12 (bit) × 2 = 768 (kbit / sec) (2) per 1 sec. Therefore, in order for the digital video signal for one screen to be read by the recording signal processing unit 11, 1.911 (M bits) / 768 (k bits / sec) = 2.49 (sec) (3) is required. Since 1/60 sec is required to write the digital video signal for one screen to the image memory 8a, the digital video signal representing one still screen is recorded on the magnetic tape 12 in about 2.5 sec. Will be recorded. Therefore, by reproducing the magnetic tape 12 on which the digital video signal and the digital audio signal are recorded as described above, the sound signal is sonicated and about 2.
It is also possible to display a still image that changes every 5 seconds.

By the way, in the reproducing operation, the position of the magnetic tape 12 (the position where the recording / reproducing head corresponds to the magnetic tape 12)
Is a position in the middle of the video signal recording area S3 + S4 having the number of pages N as shown by the symbol a in FIG. 3, for example, the identification code ID1 in the pack data of the reproduced sub-signal.
= 1. Further, since the still image video signal of the page number N-1 has already been reproduced, the still image of N-1 pages is displayed at this time.

At this time, when a command for temporarily stopping the reproduction operation is given to the reproduction signal processing unit 13 from the reproduction signal processing pad 13, the identification code ID1 changes from 1 to 0 and the identification code ID2 changes from 1 to 1. A magnetic tape is wound up to the device corresponding to the recording / reproducing head at the position where it changes to 0, that is, in the region S2 where the video signal is not recorded immediately before the head position of the video signal recording region S3 + S4 of the page number N shown in FIG. A command to return is output, and it is rewound to point b and stopped.

When the reproduction operation is started from the above-mentioned state of the still state in which the still image of page N-1 is still displayed, the reproduction position shifts from the point b to the direction indicated by the symbol c in FIG. , The video signal recording area S3 + S4 having N pages is reproduced from the beginning. That is, even if the reproduction operation is temporarily stopped while the N-1 page still image is being displayed and then the reproduction is resumed, the N-1 page still image is not lost following the N-1 page still image. It is displayed correctly.

On the other hand, when the recording operation is started from the temporarily stopped state, the recording apparatus also moves from the point b to the direction c in this case,
A new video signal is overwritten from the beginning of the video signal recording area S3 + S4 having N pages. That is, the video signals up to the N-1th page remain in a complete form without any loss for one screen, and the video signals after the Nth page are rewritten with new video signals. Therefore, even if the video signal of the number of pages N is reproduced, a new still image for one screen is displayed.

By the way, in the conventional recording / reproducing apparatus, even when the reproducing position is at the point a, the recording is temporarily stopped at that point. Therefore, when the reproducing operation is restarted next, the reproducing is performed from the point a in the direction indicated by the symbol d. The position has changed, and the video signal recording area S3 on page N
Of + S4, only the video signal of the area indicated by the code _DNB can be correctly reproduced, and a still image of N pages can be completely reproduced.
It cannot be displayed as a screen. Further, even when the recording was started from a point, it will remain in the video signal of the area indicated by the part of the video signals of N pages or sign D _NA is not rewritten, incomplete still images for N pages Will be played.

When the reproduction position is, for example, in the area S5 in which the video signal shown in FIG. 3 is not recorded and the video signal is not recorded, when a stop command is given, the stop is immediately performed at that point.
The next reproduction or recording is started from that point a1.
Even in this case, the still image to be played may be missing,
The recorded video signal is never incomplete.

As described above, according to the recording / reproducing apparatus of the present invention, when the reproducing position of the recording / reproducing head when the reproduction is temporarily stopped is in the middle of the recording area of the still image information for one screen. , The magnetic tape is rewound until the recording / reproducing head corresponds to the non-recorded non-recorded area between the still image information recording area and the adjacent still image information recording area. Therefore, when the reproduction operation or the recording operation is started next time, a still image without any loss can be reproduced and displayed, and the still image information can be prevented from being recorded in an incomplete form.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a recording / reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic view of a part of a magnetic tape on which a digital video signal is recorded by the recording / reproducing apparatus. FIG. 3 is a plan view schematically showing the correspondence between the recording area of the magnetic tape and the identification codes ID1 and ID2 of the pack data. 1,2,6 …… A / D conversion circuit, 5,15 …… Selection switch, 8a, 8b
...... Image memory, 9 ...... P / S conversion circuit, 11 ...... Recording signal processing unit, 12 ...... Magnetic tape, 13 ...... Reproduction signal processing unit, 1
6,17,19 …… D / A conversion circuit, 18 …… S / P conversion circuit, TR, TL, T
V …… input terminal, TR1, TL1, TV1 …… output terminal

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04N 5/91

Claims (1)

[Claims] 1. A recording area for sequentially recording still image information as a digital signal in a plurality of continuous areas on a magnetic tape with one screen as a unit and for recording adjacent still image information for one screen. In a recording / reproducing apparatus having a non-recording area in which no still image information is recorded, a sub-signal for discriminating whether or not a recording area for recording still image information is recorded in each area of the magnetic tape during recording. And a sub-signal recording means for reading the sub-signal from the magnetic tape at the time of reproducing and rewinding, and the reproducing position of the recording / reproducing head is on the recording area or the non-recording area of the magnetic tape based on the sub-signal. And a discriminating means for discriminating whether or not the magnetic tape is run on the basis of the discrimination result by the discriminating means in response to a temporary stop command during reproduction, and the reproducing position of the recording / reproducing head is determined by When the magnetic tape is running in the recording area, the magnetic tape is run in the rewinding direction, and the running of the magnetic tape is stopped when the discriminating means detects that the reproducing position of the recording / reproducing head has reached the non-recording area. A recording / reproducing apparatus comprising: a temporary stopping means for controlling the recording / reproducing apparatus.