KR0152051B1 - Method and apparatus for recording reproducing a data - Google Patents

Abstract

The present invention relates to a digital VCD device (D-VCR) for recording and reproducing video signals and text information digitally. It detects when the bit rate of the video signal is different and changes the speed ratio of the drum and capstan motor of the D-VCR constantly so that the track pattern of the tape remains unchanged and always remains low at high bit rate. It is possible to record all the rates, reproduce the video signals recorded by variable bitrates according to the corresponding bitrates, and the same track pattern recorded on the tape, so that the speed reduction ratio of the drum and the capstan motor is constant at any speed combination. The recorded contents can be read, and when a low bit rate video signal is inputted, the same tape can be recorded for a long time.

Description

Apparatus and method for data recording / reproducing of variable bit rate of D-VCR

1 is a block diagram showing a conventional data recording / reproducing apparatus of a D-VCR.

2 is a conceptual diagram showing a track pattern recorded on a tape.

FIG. 3 is a conceptual diagram showing, as a vector, the relationship between the stop angle and the travel angle of a recorded signal to form the tape pattern shown in FIG.

4 is a conceptual diagram showing the configuration of a signal at the time of image input.

5 is a block diagram showing a data recording / reproducing apparatus of a variable bit rate of a D-VCR according to an embodiment of the present invention.

6 is an operation flowchart for explaining the recording operation and the reproduction operation of the apparatus of the present invention.

* Explanation of symbols for main parts of the drawings

11: drum 12: capstan

13: recording and playback head 14: recording and playback amplifier

15: pilot tone detector 16: digital signal processing unit (DSP unit)

17 display unit 20 servo unit

21: drum motor 22: capstan motor

23: drum motor drive 24: capstan motor drive

25: servomicrocom 30: bit rate discriminator

The present invention relates to a digital VR device (D-VCR) for recording and reproducing a video signal and character information digitally. In particular, the present invention relates to detecting a video signal having a different bit rate from a video signal and detecting the same. Therefore, by changing the speed of the drum and capstan motor of the D-VCR, it is possible to record from high bitrate to low bitrate while keeping the track pattern of the tape unchanged and always constant. A data recording / reproducing apparatus and method for a variable bit rate of a D-VCR that can be reproduced according to a bit rate.

1 is a block diagram showing a conventional data recording / reproducing apparatus of a D-VCR. The data recording / reproducing apparatus of the D-VCR includes a drum 11 for moving the recording / playing head 13 along the track of the tape and a capstan 12 for conveying the tape at a constant speed. The servo unit 20 includes a drum motor 21 for driving the drum 11 and a capstan motor 22 for driving the capstan. In addition, the drum motor 21 and the capstan motor 22 are driven by the drum motor drive 23 and the capstan motor drive 24, respectively. The servo microcomputer 25 controls the speed of the drum motor 21 and the capstan motor 22. The servo microcomputer 25 is a drum pulse generator (hereinafter referred to as DPG) and a DFG signal from a drum frequency generator (hereinafter referred to as DFG) of the drum motor 21 to control the speed. The DPG signal from the controller is used to measure the speed of the drum motor 21. In addition, the servo microcomputer 25 receives a CFG signal from a capstan frequency generator (hereinafter referred to as CFG) of the capstan motor 22 and uses the same to measure the speed of the capstan motor 22. Further, the conventional D-VCR data recording / reproducing apparatus includes a recording / playing head 13 for recording a video signal and picking up the recorded signal. A recording / reproducing amplifier 14 is provided for flowing a recording current corresponding to the video signal during recording, and amplifying the signal picked up by the recording / reproducing head 13 during playback. The pilot tone detector 15 outputs the pilot signal b to the servo microcomputer 25 in accordance with the reproduction signal applied from the recording / reproducing amplifier 15 for tracking of the servo unit 20. The digital signal processing unit 16 processes the recording signal and the reproduction signal, and the display unit 17 shows the reproduced signal.

Now, the operation of the conventional data recording / reproducing apparatus of the D-VCR will be briefly described.

In recording, the digital signal processor 16 receives a video signal. The digital signal processor 16 processes the applied video signal digitally and outputs it to the recording / playback amplifier 14. Here, the method of driving the speed of the motor in a stable state by the DFG, DPG, and CFG signals output from the drum motor 21 and the capstan motor 22 is already known, and thus detailed description thereof will be omitted. When the motor rotates at a stable speed, the recording / reproducing amplifier 14 amplifies the applied signal and outputs it to the recording / reproducing head 13, and the recording / reproducing head 13 records the signal on the tape. At this time, the digital signal processor 16 outputs the servo reference signal c to the servo microcom 25 so that the servo microcom 25 outputs the head switching pulse a to the recording / reproducing head 13 accordingly. Video signals can be recorded.

In regeneration, the servo microcomputer 25 drives the drum motor 21 and the capstan motor 22 through the drum motor drive 23 and the capstan motor drive 24. The recording / playback head 13 thus picks up the recorded signal. The recording / reproducing amplifier 14 amplifies the picked-up signal and outputs it to the digital signal processor 16. The recording and reproducing amplifier 14 also outputs the reproducing waveform to the pilot tone detector 15 for the tracking of the servo unit 20. The pilot tone detector 15 outputs the pilot tone signal of the received signal to the servo microcomputer 25. Here, since the method for tracking the servo using the pilot tone signal is already known, a description thereof will be omitted. The servo microcomputer 25 outputs a control signal so that the respective motors rotate at a stable speed by the applied pilot tone signal. When the motors rotate at a stable speed under the control of the servo microcom 25, the servo microcom 25 outputs the servo reference signal c from the recording / reproducing head 13. The video signal read out by the recording / playback head 13 is amplified by the recording / playback amplifier 14, is signal-processed by the digital signal processing section 16, and appears on the display section 17. FIG.

However, in the conventional D-VCR data recording / reproducing apparatus, since the driving speeds of the drum and capstan motor are constant during normal reproduction (1x reproduction), recording and reproduction are possible only when the bit rate of the input video signal is constant. . Here, the bit rate indicates the number of bits (bps) at which the video signal is transmitted for one second. However, the conventional D-VCR recording / reproducing apparatus has a high bit rate because the bit rate transmitted according to the type of a program transmitted by a broadcasting station or a program transmitted by a cable or a telephone line cannot be recorded correspondingly. Regardless of the case (high quality) or low case (non-high quality), recording always consumes the same amount of tape. In other words, in the conventional D-VCR, since the rotational speeds of the drum and the capstan motor are always constant, the number of tracks for recording high bitrates of high quality and the number of tracks for recording low bitrates of low quality are the same. However, since the low bit rate video signal has a higher compression rate than the high bit rate video signal, it is possible to record on fewer tracks than the number of tracks on which the high bit rate video signal is recorded. Therefore, when the conventional D-VCR records at a low bit rate, unnecessary tape consumption occurs.

Accordingly, an object of the present invention is to solve the above problems, in the D-VCR, by varying the speed of the drum and capstan motor in accordance with the bit rate of the video signal that is variably input, without changing the track pattern of the tape, It is possible to record from high bit rate to low bit rate, especially for long time for low bit rate signal, and variable of D-VCR which can reproduce the signal according to the corresponding bit rate of the recorded video signal. An apparatus and method for recording / reproducing data of a bit rate are provided.

A feature of the present invention for achieving the above object is a digital video recording / reproducing apparatus for recording / reproducing by amplifying a video signal through a recording / playback amplifier,

Bit rate determination means for dividing the bit rate of the video signal into predetermined steps based on a predetermined reference bit rate, and the motors at respective motor speeds corresponding to the predetermined bit rate according to the determination signal of the bit rate determination means. A data recording / reproducing apparatus of a variable bit rate of a D-VCR including servo means for outputting a control signal for driving.

A feature for achieving another object of the present invention is a recording method for recording an input video signal according to a variable bit rate, the bit rate initial setting for initially setting the bit rate as a reference for recording the video signal on a tape Determining whether the bit rate of the input video signal coincides with the initially set bit rate; deactivating the recording amplifier only when the bit rate of the input video signal does not coincide with the initially set bit rate. A motor rotation control step of rotating the motor in the step, if the motor rotates at the predetermined speed, determining whether the speed of the rotating motor is stable, if it is determined that the motor speed is stable, by activating the deactivated recording amplifier A data recording method of a variable bit rate of a D-VCR comprising a recording step of recording. .

According to still another aspect of the present invention, in the method of reading and reproducing a recorded video signal according to a variable bitrate, a bitrate initial setting step of initially setting a bitrate as a reference for reading the recorded video signal Determining whether the bit rate of the read video signal coincides with the initially set bit rate, and only when the bit rate of the input video signal does not match the initially set bit rate, deactivating the playback amplifier and setting the corresponding speed. A motor rotation control step of rotating the motor in the step, if the motor rotates at the predetermined speed, determining whether the speed of the rotating motor is stable, if it is determined that the motor speed is stable, to activate and play the regeneration amplifier A data reproduction method of a variable bit rate of a D-VCR including a reproducing step.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Prior to describing the apparatus of the present invention, the principle in which the track pattern of the tape is constantly formed is always explained by changing the speed of the drum motor and the capstan motor in the same manner with reference to FIGS. 2 and 3.

FIG. 2 shows the track pattern recorded on the tape, and FIG. 3 is a conceptual diagram showing the relationship between the stop angle and the travel angle of the recorded signal to form the track pattern shown in FIG. When the moving direction of the tape and the moving direction of the head are as shown in FIG. 2, and the traveling angle is θr, if the speeds of the drum motor and the capstan motor are changed equally with reference to FIG. 3, the track pattern of the tape will always be I will explain the principle that is formed constantly.

In FIG. 3, the speed of the head drum is Vd, the tape moving speed is Vt, the capstan speed is Vr, the tape stopping angle is θs, and the driving angle is θr. .

Relative velocity Vr can be obtained through the cosine law as

Therefore, if the speed of the drum motor and the speed of the capstan motor is reduced by the same ratio n, the relative speed is as shown in the following equation (3).

Therefore, when the driving angle after the motor speed change and the driving angle before the change are compared, it is as follows.

As a result, as shown in equation (4), there is no change in the running angle after and before the change. Therefore, if the speeds of the drum motor and the capstan motor are reduced at the same rate, since the running angle does not change even after the motor speed is changed, the track pattern on the tape does not change.

Now, the apparatus of the present invention using the above-described principle will be described in detail with reference to FIGS. 4 and 5. FIG.

4 is a conceptual diagram illustrating a configuration of an input signal when an image signal is input, and is configured to send an identifier to the first half of the signal when a signal having a different bit rate is continuously input. Here, since the identifier has a bitrate value of the video signal to be applied, analyzing the identifier can know the bitrate value of the video signal currently applied. In an embodiment, the identifier 1 includes a bitrate value in which the next input video signal informs the medium bitrate program.

5 is a block diagram showing a data recording / reproducing apparatus of a variable bit rate of a D-VCR according to an embodiment of the present invention. The apparatus of the present invention further includes a bit rate discriminator 30 for discriminating the bit rate of the video signal input to the rear end of the digital signal processing unit 20 of the conventional data recording / reproducing apparatus of the D-VCR. Therefore, the same reference numerals are used for the same parts as in FIG. 1, and the description of the same components will be omitted.

First, as shown in FIG. 4, a method of recording when a video signal having a different bit rate is input will be described.

In recording, the bit rate discriminator 30 receives an image signal. The bit rate discriminator 30 prestores a reference value for determining whether the bit rate of the input video signal is high or low. In the embodiment, simply determine that the bitrate discriminator 30 has three bitrates: low, medium, and high. The initial bit rate of the present invention is determined as the medium bit rate. The bit rate discriminator 30 analyzes an identifier carrying a bit rate of an input video signal and outputs one of the low, medium, and high bit rate determination signals d. In addition, the bit rate discriminator 30 outputs the received image signal to the digital signal processor 16. The digital signal processor 16 digitally processes the video signal received from the bit rate discriminator 30 and outputs the image signal to the recording / reproducing amplifier 14. At this time, since the recording and reproducing amplifier 14 is deactivated and does not operate until the stable signal is received from the recording and reproducing head 13, the recording and reproducing amplifier 14 cannot record the video signal applied from the digital signal processing unit 16. Since the initially set bitrate is a medium bitrate, when an image signal having a medium bitrate is input, the servo unit 20 drives each of the motors as the initial setting to record the input video signal. However, when a low bit rate different from the initial setting value is input, the bit rate determiner 30 outputs the determination signal d which has been determined to the servo microcomputer 25. The servo microcomputer 25 stores the speed control reference values of the drum and the capstan motor corresponding to the bit rate determination signal d respectively applied. Accordingly, the bit rate discriminator 30 outputs a speed control signal corresponding to the low bit rate to the drum motor drive 23 and the capstan motor drive 24. Each of the drives 23 and 24 drives the drum motor 21 and the capstan motor 22, and the servo microcomputer 25 is a DFG signal or DPG signal applied from the drum motor 21 and the capstan motor 24. And a signal for controlling until the drum motor 21 and the capstan motor 22 rotate at a stable speed in accordance with the CFG signal. When the servo microcomputer 25 determines that each of the motors 21 and 22 rotates at a stable speed, the servo microcomputer 25 outputs the head switching pulse a to the recording / playback head 13. The recording / playback head 13 outputs a signal for activating the recording / playback amplifier 14. Accordingly, the digital signal processing unit 16 outputs the low bit rate video signal signaled to the activated recording / playback amplifier 14, and the low bit rate video signal is recorded on the tape through the recording / reproducing head 13; do.

At the time of regeneration, the servo microcomputer 25 first outputs a control signal to each of the motor drives 23 and 25 to drive the drum motor 21 and the capstan motor 22 at an initial set speed. The recording and playback head 13 picks up a video signal recorded at a variable bit rate on a tape and outputs it to the recording and playback amplifier 14. The recording / reproducing amplifier 14 amplifies the applied signal and outputs it to the digital signal processor 16. The digital signal processor 16 determines whether the currently recorded signal is high bit rate, medium bit rate or low bit rate. The determination signal is outputted to the servo microcomputer 25. The servo microcomputer 25 determines whether or not the rotational speeds of the drum motor 21 and the capstan motor 22 initially set correspond to the rotational speeds corresponding to the bit rates applied from the digital signal processing unit 17. According to the determination result, the servo microcomputer 25 outputs a control signal for driving the respective motors 21 and 22 at the current speed, so that the picked-up image signal is processed by the digital signal processor 16 for signal processing. And appear on the display unit 17. However, if the initially set bit rate does not match the bit rate of the currently applied video signal, the servo microcomputer 25 deactivates the recording / playback amplifier 14 through the recording / playback head 13. At this time, since the recording / reproducing amplifier 14 is deactivated, the picked-up video signal cannot be transmitted to the digital signal processing unit 16. Therefore, the output of the reproduction signal is prohibited or the entire screen existing in the memory built in the digital signal processor 16 is output. That is, when the video signal of the changed bit rate is to be reproduced, the display unit 17 keeps the digital signal until the speeds of the drum motor 21 and the capstan motor 22 are changed in accordance with the corresponding bit rate and rotated at a stable speed. By continuously outputting the previous screen embedded in the processor 16, only the same screen is displayed eventually. When the recording / reproducing amplifier 14 is deactivated, the servo microcomputer 25 outputs a control signal for varying the speed of the drum motor 21 and the capstan motor 22 for the corresponding bit rate. The drum motor 21 and the capstan motor 22 change the rotational speed according to the control signal applied thereto, and the servo microcomputer 25 applies the DFG, DPG and CFG signals from the drum motor 21 and the capstan motor 22. Control signal is output until stable rotation operation is received. When the servo microcomputer 25 determines that the respective motors rotate at a stable speed, the servo microcomputer 25 outputs the head switching pulse a to the recording / playback amplifier 13 to activate the recording / playback amplifier 14. The signal picked up by the recording / reproducing head 13 is amplified by the recording / reproducing amplifier 14 and signal-processed by the digital signal processing section 16 and then displayed on the display section 17.

Therefore, assuming that m tracks are required to record one frame at high bitrate, if the number of data that can be recorded on one track is k, the total number of recorded data is mk. Since the number of data becomes mk / n, the number of tracks required for recording is m / n, so that n times more time can be recorded on the same amount of tape.

6 shows a flowchart at the time of recording and reproduction of the data recording / reproducing apparatus of the variable bit rate of the D-VCR of the present invention. First, the bit rate of the video signal is initially set (step 110). Then, it is determined whether to record or reproduce data (step 120). First, a case in which it is determined that the recording step is described. The bit rate discriminator 30 determines whether the bit rate of the currently applied video signal is a high bit rate, a medium bit rate, or a low bit rate by a predetermined determination reference value, and outputs it to the servo microcomputer 25. The servo microcomputer 25 stores the rotation speeds of the drum and the capstan motor corresponding to the respective bit rates. First, the servo microcomputer 25 first determines whether the initially set bit rate and the bit rate of the currently applied video signal match (step 130). If the image signal coincides with the initial bitrate setting value, it is determined whether the motor speed is stable (step 135). However, if the initial bitrate setting value and the bitrate of the applied video signal do not match, first, the recording amplifier 14 is deactivated to prevent writing (step 131). Subsequently, the servo microcomputer 25 outputs a control signal to the drum and the capstan motor to rotate at a speed corresponding to the bit rate of the received video signal (step 133). Then, it is determined whether the motor speed is stable (step 135). When the motor speed is stabilized, the recording amplifier 14 is activated (step 137) and recorded on the tape (step 139). However, if the motor speed is not stable, the flow returns to step 135 and performs a plurality of steps.

The case where it is determined that the reproduction step of reproducing the video signal recorded according to the variable bit rate is described. If it is determined in the reproduction step, the digital signal processor 16 determines whether the bit rate of the video signal to be reproduced matches the initial set value (step 140). If they do not match, the digital signal processor 16 discriminates and outputs the bit rate to the servo microcomputer 25, while prohibiting the output of the reproduction signal (step 141). The servo microcomputer 25 outputs a signal for controlling motor rotation at a predetermined speed corresponding to the applied bit rate (step 143). Then, it is judged whether or not the motor speed is stable (step 145). If the motor speed is stable, release of prohibition of output of the playback signal is released (step 147), and the playback signal is output to the display unit 17 (step Step 149).

As described above, according to the present invention, the speed of the drum and the capstan motor is varied with a constant variation ratio according to the bit rate of the video signal that is variably input so that the video signal of the corresponding bit rate can be recorded without changing the track pattern of the tape. In addition, the video signal recorded for each variable bitrate can be reproduced according to the corresponding bitrate. Since the shape of the track recorded on the tape is the same, the recorded content can be read in any combination of motor drive speeds if the reduction ratio of drum and capstan is constant. The present invention provides an advantage that a low bit rate video signal can be recorded on the same tape for a long time.

Claims (6)

A digital video recording / reproducing apparatus which amplifies a video signal through a recording / reproducing amplifier for recording / reproducing, comprising: bit rate discriminating means for discriminating and discriminating the bit rate of the video signal in a predetermined step by a predetermined reference bit rate; And a servo means for outputting a control signal to drive the motors at respective motor speeds corresponding to a predetermined bit rate in accordance with the discrimination signal of the bit rate discriminating means. 2. The apparatus of claim 1, wherein the servo means comprises: a drum motor for driving a drum for moving the recording / playback head along a track of the tape and outputting DFG and DPG signals for speed control; A capstan motor for driving a capstan for transferring the tape at a constant speed and outputting a CFG signal for speed control; A drum motor drive for rotating the drum motor; In response to the capstan motor drive for rotating the capstan motor and the bit rate discrimination signal, DFG, DPG, and DFG signals are applied from the drum motor and the capstan motor to control the speed of the motors until the motors rotate at a stable speed. And a servo microcom for controlling recording and reproducing by outputting a switching pulse signal to the recording / reproducing head when the motors rotate at a stable speed. / Playback device. The method of claim 1, wherein the servo means, when varying the speed of the drum motor and the capstan motor, the speed of the drum motor and the capstan motor is added or subtracted at the same rate to always form a constant track pattern regardless of the variable bit rate of the video signal A data recording / reproducing apparatus having a variable bit rate of a D-VCR. The variable bit of the D-VCR according to claim 1, wherein the recording / reproducing amplifier is inactivated until the motor stable rotation signal is received from the servo means, indicating that the rotation speed of the motors is stable. Rate data recording / reproducing apparatus. A recording method for recording an input video signal according to a variable rate, the recording method comprising: a bitrate initial setting step of initially setting a bitrate as a reference for recording the video signal on a tape; Determining whether a bit rate of an input video signal coincides with an initially set bit rate; A motor rotation control step of deactivating a recording amplifier and rotating the motor at a predetermined speed only when the bit rate of the input video signal does not match the initially set bit rate; And determining whether the speed of the rotating motor is stable when the motor rotates at the predetermined speed, and recording by activating and recording the deactivated recording amplifier when the motor speed is determined to be stable. Data recording method of variable bit rate of VCR. A method of reading and reproducing a video signal recorded according to a variable bit rate, the method comprising: a bitrate initial setting step of initially setting a bitrate as a reference for reading the recorded video signal; Determining whether a bit rate of the read video signal coincides with an initially set bit rate; A motor rotation control step of deactivating a reproducing amplifier and rotating the motor at a preset speed only when the bit rate of the input video signal does not match the initially set bit rate; Determining whether the speed of the rotating motor is stable when the motor rotates at the predetermined speed; and regenerating by activating and playing the regeneration amplifier when the motor speed is determined to be stable. Bitrate data playback method.