JP3143237B2 - Video recording and playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video recording / reproducing apparatus, and more particularly to a video recording / reproducing apparatus having, for example, a function of automatically determining a reproducing speed.
The present invention relates to a video recording / reproducing device such as a CR and a VTR.

[0002]

2. Description of the Related Art In a conventional video tape recorder, FIG.
The rising of the control signal CTL as a trigger as in (A) and (B) is used to count the number of capstans FG in one cycle of the control signal CTL every cycle. When the recording mode is switched from the triple mode to the standard mode, for example, as shown in FIG. 7C, the number of capstans FG is continuously twice as shown in FIG. 7D. The tape speed was switched when the value was reached.

[0003]

In such a conventional video tape recorder, the tape speed is not changed until the recording mode is determined. Therefore, FIG.
As can be seen from FIG. 7, it takes 200 ms from the switching of the recording mode from the triple mode to the standard mode to the switching of the tape speed from the triple mode to the standard mode, during which the image and the sound are disturbed. The mode determination time when the recording mode is changed from the double mode to the standard mode is 133 ms, and the mode determination time is
The mode discrimination time when changing to the double mode is 100 ms
It is.

[0004] Therefore, a main object of the present invention is to provide a video recording / reproducing apparatus capable of controlling the reproducing speed faster and more appropriately.

[0005]

SUMMARY OF THE INVENTION According to the present invention, at the time of reproduction,
The transfer speed of the video tape being transferred at the first speed
Video recording / reproducing device for switching to a second speed higher than one speed
Indicates the video tape transport speed during recording.
1st tie to detect 1 timing signal from video tape
Indication of the video signal transfer means
Generating a second timing signal for generating a second timing signal
Generating means for detecting when the first timing signal is detected
The number of occurrences of the second timing signal exceeds a predetermined number
Switch the transfer speed to the third speed higher than the first speed at the time
First detection since the first timing signal was detected last time
Number of occurrences of the second timing signal before
When the number of times coincides, the transfer speed is changed from the third speed to the number of occurrences.
The feature is to switch to the corresponding second speed
A video recording and reproducing apparatus.

[0006]

When the recording mode is switched from the triple mode to the standard mode, for example, when the capstan FG exceeds "24", the tape speed is maintained in the standard mode by the speed forcing means. Thereafter, when the number of capstan FGs becomes “72”, for example, twice consecutively, the mode determination result becomes the standard mode, and the standard mode is maintained. Thus, the mode determination time is reduced.

[0007]

According to the present invention, since the mode determination time is shortened, the optimum reproduction speed can be set quickly.

[0008]

Referring to FIG. 1, a video tape recorder 10 of this embodiment includes a microcomputer 12. This microcomputer 12
The video tape 1 by the control head 14
The control signal CTL detected from 6 is
Is entered via Also, Capstan FG head 2
The FG signal of the capstan motor 22 is detected by 0, and is input to the microcomputer 12 via the amplifier 24. Then, a PWM signal is output from the microcomputer 12 according to the determination result, and the driver 26 drives the capstan motor 22 at a predetermined speed in response to the PWM signal.

Referring to FIG. 2 and FIG.
Will be described. First, in step S1 of FIG. 2, it is determined whether or not the recording mode has changed within three seconds. If there is a speed change, the speed change flag 28 is set in step S3. If there is no speed change, the speed change flag 28 is reset in step S5. Next, in step S7, it is determined whether the value of the capstan FG counted this time is larger than the previous count value. Here, if it is larger than the previous count value, it is determined in step S9 whether the speed change flag 28 is set. If not set, the tape speed is set to the standard mode in step S11, and the count value is stored in the memory 30 in step S13. On the other hand, when it is determined in step S7 that the current count value is not larger than the previous count value, and when the speed change flag 28 is set in step S9, the process directly proceeds to step S13, and the count value is stored in the memory 30. Remember.

Subsequently, it is determined whether or not the count value stored in the memory 30 in step S15 of FIG. 3 is smaller than "36". If it is smaller than "36", it is determined in step S17 whether or not the speed flag 32 is EP. If the speed flag 32 is EP, the recording mode is determined to be EP in step S19.
If not, the speed flag 32 is set to E in step S21.
Write P. On the other hand, in step S15, the memory 3
If the count value stored in 0 is not smaller than “36”, it is determined in step S23 whether or not 36 ≦ count value <60. Here, 36 ≦ count value <60
If so, the speed flag 32 is set to L in step S25.
It is determined whether or not the recording mode is P, and if it is LP, the recording mode is determined to be LP in step S27. On the other hand, step S
If the speed flag 32 is not LP in 25, LP is written in the speed flag 32 in step S29. If it is not 36 ≦ count value <60 in step S23, it is determined in step S31 whether or not the speed flag 32 is SP. If SP, the recording mode is determined to be SP in step S33. However, step S3
If the speed flag 32 is not SP in step 1, SP is written to the speed flag 32 in step S35. Steps S19, S21, S27, S29, S33 and S
After the processing in 35 is performed, the processing from step S1 is repeated again.

In the operation, when the recording mode changes from the triple mode to the standard mode as shown in FIG. 4C, the tape speed remains in the triple mode as shown in FIG. 4D even after the change. Therefore, the capstan FG is counted “24” during 33.33 ms from the point W to the point X in FIG. 4 (E), and when it exceeds “24”, the tape speed is increased as shown in FIG. 4 (D). Is changed to the standard mode and is retained. As can be seen from FIG. 4 (B), since the capstan FG is counted “72” twice consecutively from the point W to the point Z, the mode discrimination result is Z as shown in FIG. 4 (D). At this point, the standard mode is set, and the tape speed of the standard mode is maintained. Thus, the period from the point X to the point Y is 22.
22 ms, and the period from the point Y to the point Z is 33.33.
ms, the mode discrimination time is 88.88 ms, which is less than half that of the conventional 200 ms. Further, since the tape speed becomes the standard mode at the point X as shown in FIG. 4D, when the recording mode is changed to the standard mode as shown in FIG.
It takes only 3.33 ms, and the video and audio can be reproduced with extremely short disturbance.

When the recording mode is changed from the double mode to the standard mode as shown in FIG. 5C, the tape speed is changed to the standard mode at the point X as shown in FIG. 5D.
As shown in (E), the mode discrimination result becomes the standard mode at the point Z. Therefore, as can be seen from FIG. 5 (F), the mode discrimination time is 83.33 ms, and the tape speed switching time is 33.33 ns. From this, the conventional 133 ms
Video and audio disturbances are significantly improved as compared to.

On the other hand, as shown in FIG.
When the mode is changed from the double mode to the double mode, the tape speed is first set to the standard mode at the point X as shown in FIG.
Thereafter, at the point Z, the mode becomes the double mode based on the mode determination result of FIG. Therefore, both the mode discrimination time and the tape speed switching time until the double mode is set are 61.11 n.
s, which takes almost twice as long as the case of FIGS. However, since the time is still reduced as compared with the conventional 100 ns, the video and the audio are reproduced better than before.

When the count value changes a plurality of times within a certain period, the tape speed is not changed to the standard mode. In this way, the count value may change many times within a certain period of time, for example, when the control signal is lost due to the quality of the tape or other causes.In such a case, the tape is switched to the standard mode. Since the speed is not forced, the reproduction speed can be controlled stably even if the control signal is lost.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention;

FIG. 2 is a flowchart showing a part of the operation of the embodiment in FIG. 1;

FIG. 3 is a flowchart showing a part of the operation of the embodiment in FIG. 1;

FIG. 4 is a timing chart when the recording mode changes from the triple mode to the standard mode.

FIG. 5 is a timing chart when the recording mode changes from the double mode to the standard mode.

FIG. 6 is a timing chart when the recording mode changes from the triple mode to the double mode.

FIG. 7 is a timing chart showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Video tape recorder 12 ... Microcomputer 14 ... Control head 20 ... Capstan FG head 22 ... Capstan motor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 15/087 G11B 15/46 G11B 15/467

Claims (1)

(57) [Claims] 1. A video device that is transported at a first speed during reproduction.
A second speed, which is higher than the first speed, for transferring the tape;
In the video recording / reproducing apparatus, the first speed indicating the transport speed of the video tape at the time of recording.
A first timer for detecting an imaging signal from the video tape
Signal detecting means, and transfer amount of the video tape
A second timing signal for generating a second timing signal indicating
Signal generation means, the second timing signal from the time when the first timing signal is detected.
2 When the number of timing signal generations exceeds a predetermined number
Cut the transfer speed to a third speed higher than the first speed
In other words, since the first timing signal has been detected last time,
Generation of the second timing signal until it is detected twice
When the number of times matches, the transfer speed is set to the third speed.
To the second speed corresponding to the number of occurrences
A video recording / reproducing apparatus characterized in that :