JPH02302964A - Moving image recording and reproducing device - Google Patents

Abstract

PURPOSE:To solve a recording/reproducing incapable area and to increase a recording information quantity by accessing the recording/reproducing means of one side to the next track of a goal to be recorded/reproduced while the recording/reproducing means of the other side executes the recording/reproducing and executing the recording with a low modulation frequency at the recording/reproducing means of one side. CONSTITUTION:An external recording medium 19 is divided into an outer circumference side recording area 27 and an inner circumference side recording area 28, a first moving image recording/reproducing means 18 is provided corresponding to the outer circumference side recording area 27, and a second moving image recording/reproducing means 20 is provided corresponding to the inner circumference side recording area 28. By a control part 14, the input signal frequency of image data in the second moving image recording/reproducing means 20 is set at the modulation frequency lower than that in the first moving image recording/reproducing means 18, simultaneously, the both moving image recording/reproducing means 18 and 20 are successively switched, and the control is executed so that, while the one side executes the recording/ reproducing, the other side can be moved to the next recording/reproducing position. Thus, the recording/reproducing incapable area can be solved, and the recording information quantity can be increased.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for recording and reproducing moving images such as television images on a disk-shaped external recording medium such as an optical disk and reproducing them from there. This is related to equipment.

(Prior Art) Various types of moving image recording and reproducing devices using optical disks have been developed.
Specific examples include those described in Japanese Patent No. 78639. Here, as shown in Figure 3, an optical disc has video signals, audio signals, and data signals encoded in spiral or concentric information tracks that have optical transparency, reflection characteristics, phase characteristics, and polarization characteristics. Optical information such as (
recorded as bits). The information recorded on these optical discs is recorded on the spiral or concentric information tracks 4 of the optical disc 44 by rotating the optical disc 44 at a speed of 1800 revolutions per minute by a spindle 45, for example.
6, the light emitted from a light source 47 such as a laser,
The reflected light is projected through the lens 48, the half mirror 49, the reflective mirror 50, and the objective lens 51, and is modulated based on the optical information in the information track 46, and is caused to travel backwards.
It is reflected by a half mirror 51, detected by a light receiving device 53 via a lens 52, and reproduced. Here, the optical elements (47 to 53) are supported by a pickup 54 and are configured to be able to move integrally in the radial direction of the optical disc 44, so as to sequentially scan the information tracks in the radial direction. . In addition, when recording information on the optical disk 44, for example, in the optical system shown in FIG. A structure is prepared in which a modulator is arranged between the optical discs 44 and 47, and the light source 47 emits light with stronger energy than that during reproduction. This light is modulated by the modulator based on the information to be recorded. The information is projected from the inner circumference toward the outer circumference, or from the outer circumference toward the inner circumference, and in the process of track movement, a spiral or concentric information track is formed one rotation at a time.

When accessing information for new recording or reproduction, the pickup 54 is moved in the radial direction to bring it to an empty track or near the target track (coarse access), then the optical deflection means ( (not shown) to focus the light beam onto the corresponding track (
precision access).

In a moving image recording/playback device that uses a disk-shaped recording medium such as an optical disk, one screen (frame)
A moving image signal is recorded on one round of the information track, and this is written to each track continuously. Jumping back and forth allows special operations such as forwarding, fast forwarding, and reverse forwarding, as well as continuous recording/playback between discontinuous tracks. This type of method is generally called CAV.
Method (C0N8TANT ANGULA'RVELOC
ITY).

(Problem to be Solved by the Invention) However, the mass of the above-mentioned Big Ara F54 is quite large, and not only does it take time to move (coarse access), but the track density is high, so it is difficult to access it finely. Therefore, the pickup 54 is
The number of tracks that can be moved is small, and there are significant restrictions on continuous recording/reproduction between discontinuous tracks. This point will be specifically explained with reference to FIG. A moving image A on a newly formatted recording medium, for example, an optical disk.

The recording positions of B and C follow the track order.

Next, when moving image B is erased and a moving image shorter than moving image B is recorded from the Nth track, an empty track remains before moving image C is recorded. Then, after moving image A is further erased, if moving image E, which is longer than moving image A, is recorded from the 0th track,
Each moving image E is sequentially recorded up to the first track, but there is no empty track after that up to the N'th track. Therefore, if the number of tracks on which moving images have been recorded exceeds the vertical blanking period, it will not be possible to continue recording in real time following the input of the moving images to be recorded. Generally, the number of tracks used for one moving image file is several hundred or more, which far exceeds the number of tracks that can be jumped during the vertical blanking period. In this way, when erasing one moving image in an area where multiple moving images are continuously recorded and recording another moving image, the length of the subsequent moving image to be recorded is There is a restriction that the length of the previous moving image (erasure) must be equal to or shorter than that, and the area of empty tracks caused by the difference in the number of tracks between the former and the latter must be continuous. This is an area where recording/playback is not possible. Such an area will continue to increase as recording/erasing is repeated on the recording medium.

On the other hand, in the CAV method, the linear velocity of the inner circumference of the recording medium is slower than that of the outer circumference, so the length of the bit for recording information is shorter, so the laser spot diameter (generally 430nrn In areas where information is recorded at intervals equal to or shorter than 87 degrees, it is not possible to record effectively. Therefore, in order to record more to the inner circumference, the modulation frequency during recording may be lowered or the rotational speed may be increased, but in this case, the recording capacity of the recording medium as a whole will actually decrease. Therefore, the inner circumferential area to a certain extent is left as a non-recording area.

(Object of the invention) The present invention has been made based on the above circumstances.
By making it possible to access discontinuous recording/playback areas that occur during the erasing process, it is possible to eliminate areas where recording/playback is not possible, and to expand the recording/playback area towards the inner circumference of a disc-shaped recording medium. It is an object of the present invention to provide a moving image recording and reproducing apparatus that can increase the substantial amount of information recorded on a recording medium.

(Means for Solving the Problem) Therefore, in the present invention, a moving image recording/
In the moving image recording/reproducing device having a reproducing means, the external recording medium is divided into an outer recording area and an inner recording area, and a first moving image recording/reproducing means is provided corresponding to the outer recording area. In addition, a second moving image recording/reproducing means is provided corresponding to the inner recording area, and the input signal frequency of the image data in the second moving image recording/reproducing means is adjusted to match that of the first moving image. The modulation frequency of the recording/reproducing means is set to a lower value than that of the recording/reproducing means, and both of the video recording/reproducing means are sequentially switched so that while one is recording/reproducing, the other is moved to the next recording/reproducing position. It is equipped with a control means for controlling.

(Function) In such a configuration, the first and second recording/reproducing means can move to the next target track at the same time that the other recording/reproducing means is recording/reproducing, so the moving track Even if the number is large, continuity of recording/reproduction can be realized in real time, and areas where recording/reproduction cannot be performed can be eliminated. In addition, since the second recording/reproducing means compresses the information recorded/reproduced and records/reproduces at a low modulation frequency, it is possible to use the inner circumferential area, which is normally considered a non-recording area, and the overall The amount of information recorded/played can be increased.

(Example) An example of the present invention will be specifically described below with reference to FIG. Here, an optical disk 19 is used as an external recording medium having concentric or spiral information tracks, and is divided into an outer recording area 27 and an inner recording area 28, and correspondingly, A first recording/reproducing means and a second recording/reproducing means are provided. Each of these is adapted to scan each corresponding area with an optical head 18.20 provided on a slider 17.22. Each slider 17.22 has a slider motor 16.23
Each slider motor 16, 23 is controlled by a command from the controller 14. The optical disc 19 is driven by a motor 24.

An input signal 1 of a moving image to be recorded is input to a switch circuit 2, and when the switch circuit 2 is switched according to a signal from a controller 14, one of the encoders 3
, 7 and give optical signals to the optical heads 18 and 20. In this case, the input to the encoder 3 side is frame memory 6
is phrased. Further, a subtraction circuit 10 is provided between the switch circuit 2 and the encoder 7 for subtracting between the input signal from the switch circuit 2 and the signal from the frame memory 6.
A compression circuit 11 is provided which compresses the dynamic range of the output signal of the subtraction circuit 10 to 1/2.

Further, the signals detected by the optical heads 18 and 20 are supplied to the switch circuit 5 via the decoders 4 and 8, but the switch circuit 5 is switched by the signal from the controller 14, and the signals from the decoder 4 and 8 are supplied to the switch circuit 5. Select and output signals. In this case, the output to the decoder 4 side is frozen in the frame memory 9. Further, between the decoder 8 and the switch circuit 5, there is an expansion circuit 12 that doubles the dynamic range of the output signal from the decoder 7, and an addition circuit 13 that adds the output signal of the expansion circuit 12 to the signal of the frame memory 9. is provided.

Next, recording of moving images will be explained. Controller 14
When the recording command signal 25 is input to the controller 14, the controller 14 refers to the management table 15 and searches for an empty track number in the outer recording area 27 where the first frame (first odd-numbered frame) of the input moving image is to be recorded. . Based on the search number, a head movement signal is sent to the slider motor 16 to move the optical head 18 to the target track. Subsequently, the cutting edge of the switch circuit 2 is switched to the encoder 3, and recording of the first frame is started. At this time, the encoder 3 performs FM modulation on the input video signal at frequency fc, further performs Noculus modulation,
Output to the optical head 18. The optical head 18 writes a bit string in a desired track in the outer recording area of the optical disk 19 based on the pulse-modulated input moving image signal.

At the same time, the frame memory 6 phrases the first frame of the input image signal. Furthermore, the controller 14 simultaneously refers to the management table 15 to search for an empty track in the inner recording area 28 where the second frame (the first even-numbered frame) of the input image signal is to be written, and sends a head movement signal to the slider motor 23. is output, and the optical head 20 is moved to the target track. Thereafter, when the recording of the first frame is completed, the cutting edge of the switch circuit 2 is switched to the encoder 7 side. Therefore, the subtraction circuit 10 calls the frame memory 6 in which the first frame is stored, and performs subtraction (difference calculation) between the second frame and the first frame. Furthermore, the compression circuit 11 compresses the dynamic range of the difference between the image signals to 1/2 of the input moving image signal. Then, the encoder 7 performs FM modulation at a frequency of 1/2fc and further pulse modulation,
Output to the optical head 20. The optical head 20 writes a pit string in a desired track in the inner recording area 28 of the optical disk 19 based on the pulse-modulated differential signal.

This writing has a modulation frequency that is 1/2 compared to the outer peripheral portion. While recording the second frame, the controller 14 refers to the management table 15 and determines whether the third frame (odd-numbered next rank)
In order to record
Based on the search result, the optical head 18 is moved to the target empty track. In this way, the optical heads 18 and 20 alternately record odd frames and even frames of the input moving image signal in the respective areas 27 and 28 of the optical disc.

Next, reproduction of moving images will be explained. When the reproduction signal 26 is input to the controller 14, the controller 14 refers to the management table 15, determines the track number in which the first frame of the moving image signal to be reproduced is recorded, and sends a head movement signal to the slider motor 16. The optical head 18 is moved to a target track in the outer recording area 27. continue,
The input light of the switch circuit 5 is switched to the decoder 4, and reproduction of the first frame of the reproduced moving image is started. Decoder 4 demodulates the pulse-modulated moving image signal and outputs it to switch circuit 5 and frame memory 9. The frame memory 9 freezes the first frame. At the same time, the controller 14 searches the management table 15 to find the track number of the inner recording area 28 where the second frame is recorded, and moves the optical head 20 to that track. When the reproduction of the first frame is completed, the switch circuit 5 switches the input light to the decoder 8 side. As a result, the optical head 20 starts reproducing the second frame from the already accessed track in the inner recording area.

The reproduced signal is demodulated by the decoder 8, its dynamic range is expanded, and then added to the first frame signal recorded in the frame memory 9 and output. At the same time, during reproduction of the second frame, the controller 14 refers to the management table 15 to search for the track number of the outer recording area 27 where the third frame is recorded, and causes the optical head 18 to access it. In this way, optical spatula P18
and 20 alternately reproduce odd-numbered frames and even-numbered frames of the reproduced video signal from the optical disc 19.

In this way, while one recording/reproducing means is recording/reproducing, the other recording/reproducing means is accessed to the next track to be recorded/reproduced, so sufficient seek time can be taken, so that It is possible to continuously record/reproduce between consecutive tracks in real time, thus eliminating areas where recording/reproduction is impossible.

In addition, since the modulation frequency is lowered when recording/reproducing to the inner recording area, the inner area of the disc-shaped recording medium with a slow linear velocity can also be used to increase the overall storage capacity. become.

The embodiment shown in FIG. 2 is another embodiment of the invention,
The optical head and its control unit are the same as those in the embodiment shown in FIG. 1, and are therefore omitted. The signal processing for recording moving images here is as follows. That is, in recording the first frame, the optical head 18 is removed, as in the previous embodiment.

After moving to an empty track in the peripheral side recording area, the input moving image signal 1 is digitally converted by a ψ converter 30 and inputted to an encoding circuit 32 via a switch circuit 31, where an error correction signal is added. Furthermore, band compression encoding is performed and the data is recorded by the optical head 18.

At the same time, the first frame is frozen in the frame memory 33. Next, in recording the second frame, the switch circuit 3
1 output light is switched to the encoding circuit 36 side, and the subtraction circuit 3
4, the signal of the first frame from the frame memory 33 is subjected to inter-frame difference calculation, and this is logarithmically compressed in the compression circuit 35 to reduce the bit rate to 1/2, and then the encoding circuit 3
After adding an error correction code and performing band compression encoding in step 6, the optical head 20 records on a predetermined track in the inner recording area. Thereafter, in the same manner, the output light of the switch circuit 31 is switched and signal processed every odd-numbered frame and even-numbered frame.

Further, signal processing for reproducing moving images is as follows. That is, first, the optical head 18 is moved to the target track in the outer recording area where the first frame is recorded, the recorded signal is read out, decoded by the decoding circuit 41, and sent to the converter 43 via the switch circuit 42. to convert it into a predetermined analog video signal. This first frame signal is, on the other hand, frozen in the frame memory 40. During this time, the optical head 20 is moved to a predetermined track in the inner recording area where the second frame is recorded. After reproducing the first frame, the input light □ of the switch circuit 42 is transferred to the decoding circuit 37.
to start reading signals from the optical head 20. The read signal is decoded by a decoding circuit 37, expanded in bit number by an expansion circuit 38, and then sent to an addition circuit 39.
The signal is added to the signal from the frame memory 40 and outputted to the converter 43 via the switch circuit 42 as an input analog moving image signal. Similarly, the optical heads 18 and 20 alternately read out each odd-numbered frame and each even-numbered frame, and sequentially process the data to reproduce a moving image signal.

In the above embodiment, switching of the recording/reproducing means is performed every frame of the moving image, but it is of course possible to switch the recording/reproducing means every multiple frames.

(Effects of the Invention) The present invention has been described in detail above, and while one recording/reproducing means is recording/reproducing, the other recording/reproducing means is moved to the next target track to be recorded/reproduced. This makes it possible to perform real-time recording/playback between discontinuous tracks, and prevents the occurrence of unrecordable/playable areas during repeated recording/erasing on the recording medium. By recording at a low modulation frequency with the recording/reproducing means, the recording area can be expanded to the inner circumferential area of the recording medium, which is normally not used, and the overall amount of information storage can be increased. It will be done.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing one embodiment of the present invention, FIG. 2 is a schematic block diagram showing a signal processing section of another embodiment, and FIG.
FIG. 4 is a schematic diagram showing a conventional optical system, FIG. 4 is a diagram schematically showing the storage area of a disk in that case, and FIG. 5 is a diagram schematically showing the actual recording/erasing. 2.5...Switch circuit, 3,7...Encoder,
4.8...decoder, 6,9...frame memory,
10... Subtraction circuit, 11... Compression circuit, 12...
- Expansion circuit, 13... Addition circuit, 14... Controller, 15... Management table, 18.20... Optical head, 19... Optical disk, 27... Outer circumference side recording area,
28...Inner recording area

Claims (1)

[Claims] In a moving image recording and reproducing device having a moving image recording/reproducing means for recording moving images on a disk-shaped external recording medium and reproducing them from the disk-shaped external recording medium, the external recording medium is divided into an outer recording area and an inner recording area. A first moving image recording/reproducing means is provided corresponding to the outer recording area, and a second moving image recording/reproducing means is provided corresponding to the inner recording area. , setting the input signal frequency of image data in the second moving image recording/reproducing means to a lower modulation frequency than that in the first moving image recording/reproducing means, and sequentially switching between the two moving image recording/reproducing means; 1. A moving image recording and reproducing apparatus, comprising: a control means for controlling one of the apparatuses to move the other to the next recording/reproducing position while the other is recording/reproducing.