JP2532980B2 - Self recording re-judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a self-recording / re-determining device such as a VTR.

(B) Conventional technology For example, in Japanese Patent Laid-Open No. 61-110358 (G11B15 / 467), in a video tape recorder or the like, the capstan servo system is incorporated so that the envelope of the reproduced video signal is taken in and the envelope is maximized. An auto-tracking device for controlling the delay amount (tracking data) of the reproduction control signal (or reference signal) is described.

(C) Problem to be Solved by the Invention By the way, in the case of self-recording / reproducing, the reproduced image quality is generally better if it is not performed. This is because the auto tracking operation cannot trace exactly the same as when recording. Therefore, it is desirable that the auto-tracking device has a function of determining whether or not the self-recording / reproduction is performed and determining whether or not to perform the auto-tracking operation.

(D) Means for Solving the Problems In the present invention, when the tracking data after the end of the auto-tracking operation is within the predetermined range from the standard tracking data, it is determined that the self-recording is performed.

In addition, in order to make a more accurate determination, the variation in the envelope of the playback output is examined, and the condition that the fluctuation is large and / or the VTR that employs FM recording for the rotary head of the audio signal (other than the one for video), When a plurality of conditions are true, the self-recording / playback is determined by combining the condition that the auto-tracking result of only the video signal and the auto-tracking result of only the audio signal differ by a predetermined amount or more with the above condition.

(E) Operation Therefore, according to the present invention, it is possible to determine whether or not the self-recording is performed by using a predetermined condition, for example, a tracking control amount, and thus there is an advantage that it can be easily identified.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

Generally, VTR is used for tracking control,
During recording, the CTL signal (30 Hz) is recorded in the longitudinal direction of the tape. During reproduction, tracking servo is executed by comparing the phase of the reproduced CTL signal with the reference signal and controlling the tape running phase.

Then, the delay amount of the reproduction CTL signal is adjusted so that noise is not generated on the reproduction screen during compatible reproduction. Therefore, this delay amount is the tracking data.

In FIG. 1, 1 and 2 are rotary heads of the video, 3,
4 is an audio rotary head, 5 is an RF switching (RFSW) pulse input terminal for video head switching control, 14 is a signal AF switching (AFSW) pulse for delaying the RFSW pulse to control audio head switching Is a creation circuit for creating. Reference numerals 6 and 7 are preamplifiers, 8 and 9 are envelope detection circuits, 10 is a tracking control microcomputer, 11 is a capstan servo circuit, 12 is a variable delay circuit, and 13 is a reproduction CTL signal input terminal.

The outputs of the rotary heads 1 and 2 of the video are input to the detection circuit 8 as a signal of one system by RFSW. Detection circuit 8
Now, extract the playback output envelope. Similarly,
The outputs of the audio rotary heads 3 and 4 are also input to the detection circuit 9 as a single-system signal by AFSW. The detection circuit 9 extracts the envelope of the audio reproduction output.

The microcomputer 10 uses the outputs of the detection circuits 8 and 9 as the input of the A / D input. The microcomputer 10 has an A / D converter,
The analog value supplied to this A / D input is converted into a digital value and taken in at a predetermined timing. Further, the microcomputer 10 is provided with an RFSW signal for timing control and a mode signal for controlling the timing at which ATR auto tracking is started.

First, a general ATR is a microcomputer 10 as shown in Fig. 3.
When the PLAY mode signal is detected at, the ATR operation is started. Next, the rising edge of the RFSW signal is detected and the detection circuit 8
Input the output after A / D conversion. This is repeated at a predetermined sampling interval. This sampling interval is 1ms
It is considered as an interval. This sampling is executed for one field period (may be one frame period). All sample values in one field period are added (integrated) to obtain a value N corresponding to the current envelope. At this time, if tracking adjustment is not completed, control is performed to find the maximum value of this envelope.

Therefore, if it is not the maximum value here, the delay amount is changed by a predetermined amount. This is instructed by the microcomputer 10 to the variable delay circuit 12. If it is determined to be the maximum value, the adjusting operation ends. When the adjustment operation is completed, the standard tracking data S
It is checked whether or not the tracking data N for the maximum value of the envelope is within a predetermined range from (the central value of the delay amount of the reproduction CTL signal). If it is within the range, it is determined to be self-recording and the tracking data N is replaced with the standard tracking data S. If it is out of the range, it is determined to be compatible reproduction and the tracking data N is used as it is. This completes the ATR operation.

Further, although the ATR operation is performed once in the above-described embodiment, the ATR operation may be restarted when the maximum value exceeds 0.8 or 1.2 and falls below or exceeds the maximum value.

FIG. 4 is a diagram showing another embodiment. First, the microcomputer 10 performs RF.
The rising edge of the SW signal is detected and the detection circuit 8 output is A / D
Convert and enter. This is repeated at a predetermined sampling interval. The sampling interval is, for example, 1 ms. This sampling is performed for one field period. (It may be one frame period). All sample values for one field period are stored in memory. Then, the maximum value M and the minimum value I are extracted from the sample values of this one field. Further, the minimum value I is subtracted from the maximum value M to calculate the difference Y (second
See figure).

Next, the predetermined value X and the output value Y are compared, and when X <Y, it is determined that compatible reproduction is performed, and the value obtained in FIG. 3 is used as the tracking data as it is. When X ≧ Y, the standard tracking data S and the tracking data N are compared in the same manner as the judgment block B in FIG. 3, and when it is within the range, it is judged as self-recording and the tracking data is converted to the standard tracking data S. replace. If it is out of range,
Even if the detection output is flat (that is, when there is no output difference), it is judged as compatible reproduction and the tracking data is N as described above.
Use the value of as is.

FIG. 5 shows the embodiment of FIG. 3, and is a method of observing the difference between the tracking data and the maximum value of the video detection output and the audio detection output.

Therefore, the part surrounded by the dotted line is the AT from the video in Fig. 3.
The description is omitted because it is the same as the R operation. Therefore, as shown in FIG. 5, the tracking data for the maximum envelope value is first obtained on the video side, and then the tracking data for the maximum envelope value is obtained on the audio side by the same method. When the tracking data for the video side and the tracking data for the audio side are respectively obtained, the tracking data are compared, and it is determined whether the comparison result (difference between the two) is within a predetermined range set in advance. If it does not fall within the predetermined range, it is determined that the reproduction is compatible, and the tracking data uses the value obtained in FIG. 3 as it is. When it is within the predetermined range, the standard tracking data value S and the tracking data N are compared as in the case of the judgment block B in FIG. 3, and when it is within the predetermined range, it is judged as self-recording and the standard tracking data value S
Replace with If the difference is out of the range, for example, even if the difference in the tracking data is within the predetermined range, it is determined that compatible reproduction (other recording) is performed, and the value N of the tracking data is used as it is as described above.

A method of combining the embodiments of FIGS. 4 and 5 is also conceivable. For example, the variation of the envelope (Fig. 4),
When either the difference between the audio and video auto-tracking results (Fig. 5) or either condition becomes true, the third
A configuration for performing the determination shown in the figure is conceivable.

If the envelope has a large variation (a large difference between the maximum value and the minimum value indicates a large variation), it is considered that the track on the tape and the trace locus of the head are slightly different, It is likely to be compatible playback. However, since it is dangerous to make a judgment based only on the variation in the envelope, it is also checked whether or not the tracking data is similar within the predetermined range of the standard value.

The difference in the results of auto-tracking based on the audio and video playback signals (difference in tracking data) is different between the device used for recording and the device used for playback (the positional relationship between the video and audio heads is different).
It is thought that it shows that. Even in this case, it is dangerous to judge by itself, so video (or audio)
It is also checked whether the tracking data of is within a predetermined range.

As described above, basically, the auto-tracking operation is prioritized, and under certain conditions, the auto-tracking operation is canceled, the tracking data is set to the standard value, and the playback operation is continued. .

A method of discriminating between self-playback and compatible playback based on the shape of the envelope is also conceivable. That is, in the case of self-playback, when the tracking state changes, the envelope is almost flat and only the level changes, whereas in compatible playback, the first half of the envelope is due to the linearity of the track. The envelope shape changes because the level in the latter half, or in the middle, decreases particularly.

That is, the tracking state is shown in FIG.
When the above changes (is the best state), the shape of the envelope changes, for example, as shown in FIG.

FIG. 9 shows a flowchart when this discrimination method is used. Auto tracking (AT
R) The operation is started. In the auto-tracking operation, first, the tracking value (the delay amount given to the reproduction control signal) is set to the value (tracking center value) at the time of self-recording / playback. In this state, the envelope level for one frame is sampled at 1 msec intervals and summed (integrated) to obtain a value indicating the envelope level.

At the start of ATR, to determine the shape of the envelope,
Of the 15 samplings for one field, the sum of the first and second sampling values representing the first half, the sum of the 7th and 8th sampling values representing the center, and the latter half The representative sum of the 14th and 15th sampling values is calculated and stored. This is AT
R Three numerical values representing the envelope shape at the start of the R, which will be used later.

Next, the envelope levels are compared. This is to find the point where the envelope becomes the maximum, and the previous level and the level obtained this time are compared.
The operation is controlled by this result.

After the level comparison is completed, the condition is branched according to the comparison result and the past operation. If the ATR operation is completed, proceed to the next step, which is determination of self-recording / playback / compatible playback.

At the start of ATR, there is no value to compare, so the tracking value is changed by a predetermined amount. The direction for changing the tracking value is predetermined, and first, the eighth
As shown in the figure, the delay amount is changed in the direction of increasing (from). After the change, the sampling of the reproduction envelope is executed again. Then, this loop is repeatedly executed until the ATR operation is completed.

The change of the tracking value will be executed as follows. If the current level is large compared to the previous envelope level, the direction of change does not change. When the current level becomes smaller than the previous level continuously for a predetermined number of times (for example, three times), the direction of change is changed to the direction in which the delay amount is decreased, that is, it is determined that the point in FIG. 8 has been reached. That is why.

Even after reversing the change direction, if the current level is large, the change continues in the same direction. And a predetermined number of times (eg 3
It is assumed that the envelope becomes maximum at the tracking value a predetermined number of times (three times) before the current level becomes smaller, that is, at the time when it is determined that the point in FIG. 8 is reached. I reckon. Setting this value ends the ATR operation.

Data collection for determining the shape of the envelope is also performed at points and in FIG. That is, the shape of the envelope is checked at three places.

Next, a method of discriminating self-recording / reproducing / compatible reproduction will be described. First, it is determined whether the envelope level D at the end of the ATR operation is higher than a predetermined reference level Z. If it is smaller, it is immediately discriminated as compatible reproduction. If so, proceed to the next condition. In the next step, envelope shape determination is performed.

The envelope shape is discriminated as shown in FIG.
At each checkpoint, the values representing the levels of the first half, the center, and the second half are stored and used.
The level difference between the first half and the center is A, and the level difference between the second half and the center is B
And If the value of A or B is larger than the predetermined value X, it is determined that the shape is not flat. For example, if it is down by 25% or more, it may be determined that it is not flat.

If it is determined that two or more of the three check points are not flat, it is determined that compatible reproduction is performed. On the contrary, when the number of flat points is two or three, the process proceeds to the next step.

In the next step, the self-recording / compatible playback is determined according to how far the standard tracking value (delay amount in the case of self-recording / playback) and the tracking value after ATR are from each other. In other words, if the tracking value after ATR is not within the predetermined range (± Y) centered on the standard tracking value (the difference C <Y between the tracking value after ATR and the standard tracking value is C <Y), then compatible reproduction is performed. to decide. If it is within the range, it is determined to be self-recording. In the embodiment, this predetermined range is changed according to the result of shape discrimination.

In other words, in this step, it is checked whether the difference C between the tracking center value and the tracking value after ATR is smaller than the predetermined value Y. If this value Y is flat twice, Changed in case of 3 times. When it becomes flat all three times, it is determined that the possibility of self-recording / reproducing is higher than that of the shape determination. Therefore, the value of Y is increased to increase the range for determining self-recording / reproducing. If the flat state is only two of three times, it is possible that compatible playback is possible, and the judgment to judge self-recording is made narrower and the condition is made more severe to improve the accuracy of self-recording judgment. I'm wearing. When the self-recording / reproducing / compatible reproduction is discriminated, a predetermined operation is executed according to the result. For example, in the case of the embodiment shown in FIG. 9, when it is determined by the operation of the flowchart that the self-recording is performed and the tracking value after ATR is within the predetermined range from the tracking center value, the tracking value is forcibly set to the tracking center. Perform an action. The predetermined range in this case is set narrower than the narrow range of the predetermined range shown in FIG.

According to this embodiment, it has no FM audio function.
Accurate discrimination is possible even with VTR.

(G) Effect of the Invention As described above, according to the present invention, it is possible to easily determine whether the recording / reproduction is self-recording.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the embodiment, FIG. 2 is a waveform diagram showing an example of the waveform of the envelope, FIGS. 3, 4, and 5 are flow charts showing the operation of the embodiment, and FIG. FIG. 7 is an explanatory diagram of the operation of FIG. FIG. 7, FIG. 8 and FIG. 10 are explanatory views of other embodiments, and FIG. 9 is a flow chart. 1, 2, ... Video head, 3, 4 ... Audio head, 8, 9 ... Envelope detection, 10 ... Microcomputer, 12
...... Variable delay means.

Claims (2)

(57) [Claims] 1. When the best tracking data obtained by an auto-tracking device that obtains the best value of the tracking data based on the reproduction output is within a predetermined range from the standard tracking data, it is determined that the self-recording / reproduction is performed. Self recording re-judgment device. 2. A condition that the magnitude of variation in the reproduction envelope within a predetermined period is less than or equal to a predetermined value, and / or a difference between the best tracking data based on video output and the best tracking data based on audio output is smaller than a predetermined value. And a self-recording / re-judging device which judges that the self-recording / reproducing is performed when the conditions described in claim 1 are both satisfied.