JP2001045433A - Video signal generator and video signal generating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video signal generator that generates a copy prevention signal whose detection and deletion are difficult. SOLUTION: A changeover device 5 properly selects information of a pattern part of a video signal stored in a memory 3 or information denoting a waveform of a synchronizing signal from a ROM 4 to produce a copy prevention signal. In this case, a trailing edge not substantially in existence is inserted to a part just before a horizontal synchronizing signal to prevent a normal operation of a line counter in a recorder recording this signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unauthorized copy preventing technique for preventing an unauthorized copy from being made from video software or the like.

[0002]

2. Description of the Related Art Conventionally, as a technique for preventing copying of an analog video signal, there is a technique described in Japanese Patent No. 2881432, for example. In this technique, copy protection is performed by inserting a waveform such as that shown as "output of modulator 12" in FIG. 3 in a part of the vertical blanking period.

[0003]

However, this signal has a large signal waveform during an active period in a predetermined line of a vertical retrace period of a video signal (a period during which a picture signal is loaded in a line other than the vertical retrace period). If a malicious person intentionally attempts to break copy protection, the presence of the signal can be easily confirmed with a general electronic instrument such as an oscilloscope, and
There is a problem that the signal waveform confirmed in this manner can be removed relatively easily by those who have basic knowledge of the video signal and the electronic circuit.

[0004] Further, the above-mentioned prior art is based on NTS in Japan and the United States.
This is for a conventional video signal such as a C system signal or a PAL system signal in Europe or the like.
It was not for five progressive scan signals or the like.

[0005] Therefore, in the present invention, it is difficult to confirm or remove the presence of the horizontal scanning lines 52 compared to the conventional example.
An object of the present invention is to generate a copy protection signal capable of performing effective copy protection corresponding to a new signal system such as a signal of five progressive scan systems.

[0006]

According to the present invention, there is provided a video signal generating apparatus comprising: a video information output means for outputting video information of a picture portion in a video signal; Synchronization information output means for outputting such information, the video information from the video information output means, and generation output means for generating and outputting the video signal from information on the synchronization signal portion from the synchronization information output means; And a means for providing a falling edge from the black level of the video signal toward the synchronization leading end level immediately before the horizontal synchronization signal in a predetermined line during a vertical retrace period of the video signal, wherein the predetermined line is provided. Is
In the vertical blanking period, two or more lines do not exist continuously, and the falling edge exists only in a part of frames or fields in the video signal. .

[0007] The video signal generating method according to the present invention outputs video information of a picture portion in the video signal, and outputs information on a synchronization signal portion present at regular intervals in the video signal. In the video signal generation method for generating the video signal based on information and information on the synchronization signal portion, the video signal is synchronized from a black level of the video signal immediately before a horizontal synchronization signal on a predetermined line in a vertical retrace period of the video signal. It is characterized by inserting a falling edge toward the leading edge level, wherein the predetermined line is a plurality of lines that do not exist two lines continuously in the vertical retrace period, and the falling edge is It is characterized in that it exists only in some frames or fields in a video signal.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can prevent copy by generating a video signal in which a signal waveform of a horizontal synchronizing signal is different from a conventional waveform in a vertical blanking period. The details will be described.

FIG. 1 is a block diagram showing an example of a reproducing apparatus to which the video signal generating apparatus according to the present invention is applied. In FIG. 1, a reproduction signal reproduced from a recording medium 1 such as an optical disk, a magnetic disk, or a magnetic tape by a reproduction head (not shown) is input to a reproduction processing circuit 2 to obtain a digital video signal representing a picture. Then, this digital video signal is temporarily stored in the memory 3 thereafter.

On the other hand, information representing the waveform of the synchronizing signal portion is stored in the ROM 4 in the form of a digital signal. Therefore,
Microcomputer and SSG (Sync signal generator) not shown
The appropriate part of the synchronization signal waveform stored in the ROM 4 and the video signal temporarily stored in the memory 3 are switched by the switch 5
, And the data is read out by the D / A converter 6.
An analog video signal is obtained by performing A-conversion and outputting.

In such a reproducing apparatus, the waveform around the horizontal synchronizing signal is generally as shown in FIG. In the embodiment shown here, the waveform of the synchronization signal portion is mainly described, so that the color burst signal and the signal of the picture portion are partially omitted in the drawings.

Next, FIG. 3 shows a waveform of a so-called 525P analog video signal in the vicinity of a vertical retrace period of a progressive scan (sequential scanning) system with 525 horizontal scanning lines. Now, the recording medium 1 (for example, a DVD disk)
It is assumed that video information corresponding to 25P is recorded, and a synchronizing signal is added to the information and output as an analog signal.

For this purpose, the ROM 4 stores waveforms around the horizontal synchronizing signal as shown in FIG. 2A and the vertical synchronizing signal (V-
Sync.) Peripheral waveforms are recorded, and these and reproduced picture signals are appropriately switched and output in chronological order. Here, in the present invention, for example, FIG.
A waveform in which a pulse having the same level as that of the sync signal sync chip and a narrow pulse width is arranged around the horizontal synchronizing signal as shown in FIG. While inserting the horizontal synchronization signal shown in FIG.
At the location indicated by, a signal having the waveform shown in FIG. 2B is inserted instead of the normal horizontal synchronization signal shown in FIG.

In the waveform of FIG. 2B, the length of each part on the time axis is set to, for example, 0.4 μs for d1 to d4, 0.46 μs for d6 to d9, and 2.34 μs for d5. Is done. As will be described later, the signal to be inserted in place of the horizontal synchronization signal shown in FIG. 2A has a structure of a portion subsequent to the horizontal synchronization signal portion (portion indicated by d5) of the waveform in FIG. May be omitted and the waveform may be equivalent to that shown in FIG. 7A. Further, as shown in FIG. 7C, the falling edge of the horizontal synchronizing signal is simply placed before the original falling position (for example, 0.
(5 to 2 μs).

Hereinafter, an example of a recording apparatus for recording a signal having such a waveform, and how a normal signal generated by the video signal generating apparatus according to the present invention enters the recording apparatus, Explain if the record is disturbed. Now, FIG.
Let us consider the case of recording an analog video signal of 525P as shown in FIG.

[0016] A recording apparatus for recording such a 525P analog video signal is not currently commercialized for home use, but is a W-VHS as a recording apparatus capable of recording such a signal. A video tape recorder of the (registered trademark) system or a digital tape recorder having an analog input, and a digital disk recorder expected to be commercialized in the future are conceivable.

[0017] Among these recording apparatuses, the W-VHS video tape recorder is capable of recording a high-definition television signal of the Japanese Hi-Vision system with 1125 horizontal scanning lines and a frame frequency of 30 Hz. Is a signal having a frame frequency of 60 Hz with 525 horizontal scanning lines. Therefore, for the 525P signal, the 1/30 second period (2
1050 horizontal scanning line signals are present in a frame period), and this signal is within the recording capability of the W-VHS video tape recorder.

Therefore, it is conceivable to record a 525P signal using the basic structure of the video tape recorder of the W-VHS system. In the W-VHS system, for example, Japanese Patent Application Laid-Open No. 6-315132 describes. Although analog recording is used, the input video signal is converted into a digital signal by A / D conversion as a signal processing at the time of recording. , And D
The signal is recorded while simultaneously forming two tracks on the tape as an analog signal again after the / A conversion.

Here, when the picture portion is stored in the memory and inserted into a predetermined position in the recording format, for the picture portion, the line number in the video signal of the signal being taken in is determined. It is necessary to recognize and process. This is not limited to the video tape recorder of the W-VHS system, but also applies to a recording device such as a digital tape recorder or a digital disk recorder. Therefore, the present invention is to make it impossible to record an original video signal by erroneously recognizing the line of the signal being processed.

In order to extract a picture while recognizing a line number in a recording apparatus such as a digital tape recorder or a digital disc recorder, first, the number of lines is counted based on a vertical synchronization signal, and the picture is stored in a memory. It is necessary to capture, and it is necessary to generate a line pulse for that. Hereinafter, a line pulse generation method for counting the number of lines will be described with reference to FIGS.

FIG. 4 is a diagram showing a configuration of a circuit for generating a line pulse in the recording apparatus. A synchronization signal is separated from an incoming video signal by a synchronization separation circuit 11. FIG. 5A shows a part of an incoming video signal, and a pulse protruding downward is a horizontal synchronization signal. Note that the color burst signal and the signal of the picture portion are omitted in FIG.

The horizontal synchronizing signal separated by the synchronizing separation circuit 11 of FIG. 4 is delayed by a predetermined amount (for example, 10 clocks of a clock signal to be described later) by the delay means 12, and the delay synchronization signal shown in FIG. A signal is output. Here, even if the delay means 12 is not used, if a delay is caused by the influence of a low-pass filter or the like in the synchronization separation circuit 11, this delay may be used as it is.

The delay synchronization signal from the delay means 12 is
During a predetermined period from the rising edge, the synchronization separation circuit 11
Is masked by the masking means 13 so as not to affect the operation of the line pulse generation described later even if the noise or the like is erroneously separated and output as a synchronization signal, and a signal as shown in FIG. . In other words, a signal is generated that becomes H for a predetermined period from the rising edge of the delay synchronization signal, and becomes L in other periods.

On the other hand, the counter 14 has the masking means 13
And 28.63, the delayed synchronization signal masked by
A clock signal is input from a clock signal generator 15 that generates a 6 MHz frequency clock signal. Here, the counter 14 counts the input clock signal and cyclically takes a value from 0 to 909. Set.

That is, the counter 14 counts up the count value by one based on the input clock signal and
After taking the value of 09, the operation of counting up from 0 again is repeated, but is set to a predetermined count value at the rising edge of the masked delayed synchronization signal.

Here, 910 clocks, which is one cycle of the counter 14, correspond to one horizontal scanning period, and the delay amount of the delay synchronization signal is set to 10 clocks. Therefore, the timing at which the count value of the counter 14 becomes "0" Corresponds to the timing of the leading portion of the horizontal synchronization signal of the input video signal. Therefore,
The count value of the counter 14 and the predetermined value k
0 (in this case, “0”) is compared, and when these values match, a pulse is output and this is used as a line pulse (see FIG. 5E).

As described above, by adjusting the output timing of the line pulse to the timing of the leading edge of the horizontal synchronizing signal, it is not only a pulse for counting the number of lines from the vertical synchronizing signal, but also a pattern during the horizontal period. It can also be used as a reference pulse for extracting a part.

The operation of such a recording apparatus that counts line pulses when a signal generated as in the present invention is received will be described. FIG. 5F shows a part of the vertical blanking period of the signal of the present invention. The periphery of the first horizontal synchronization signal in FIG. 5 is the same as that of the related art, but the periphery of the next horizontal synchronization signal is shown in FIG. It is in the form as follows.

In this case, the delayed synchronizing signal is as shown in FIG. 11G, and the masked delayed synchronizing signal corresponding to FIG. 10C is as shown in FIG. The falling edge of the masked delayed synchronization signal is positioned slightly before the horizontal synchronization signal portion.

Therefore, as shown in FIG. 1I, the counter 14 counts a line pulse (for example, 90
Before reaching the next “0” counted to 9, the value is set to a predetermined value (for example, “10”), and counting is started again from this value. It will not be output.

Here, the reason why the waveform of FIG. 2B is inserted every other line and is not continued for two or more lines is that if two or more lines are continuous, the first line pulse is lost but the next line pulse is lost. In the case of, the count number “0” at which the line pulse is output reaches a position shifted before the horizontal synchronization signal, and the line pulse is output, so that only a shift occurs in the line number for one line. Yes, despite the insertion of many deformed signals, the vertical displacement of the recorded image is small, and only a small screen displacement occurs in the reproduced image, and the deterioration of the image becomes extremely small. is there.

Further, in order to make the image deterioration effective, for example, a frame to which the above-mentioned deformation signal is added and a frame to which no deformation signal is added are repeatedly output for every one frame or for every longer period. By doing so, the picture reproduced at the normal position in the vertical direction and the picture shifted in the vertical direction are displayed alternately periodically, so that the reproduced image when the copy protection is performed can be more improved. It can be unsightly.

As described above, in the present invention, of the waveforms around the horizontal synchronizing signal, only the position of the first falling pulse from the black level to the sync tip level (synchronous leading edge level) is used. Therefore, a waveform as shown in FIG. 2C in which the falling edge of the horizontal synchronizing signal that is present at every constant period is shifted forward may be used instead of the waveform of FIG. 2B.
Here, when a waveform as shown in FIG.
It goes without saying that the synchronization signal waveform data held in M4 can be simplified.

By the way, the waveform as shown in FIG. 2 (B) has a characteristic waveform. Therefore, in a recording apparatus to which a video signal to which such a waveform is added is inputted, this characteristic waveform is converted. This is suitable for performing the copy prohibition process by detecting it. That is, the waveform as shown in FIG.
Since only the sync chip level period is different from the waveform of the synchronization signal shown in (2), the condition of the transmission path is poor, and it may be difficult to make accurate determination of copy prohibition when the signal is slightly deteriorated. It is conceivable that the waveform as shown in FIG. 2B has a difference that accurate determination of copy prohibition is easily performed even in such a situation, and the reliability of the determination can be improved.

For the purpose of further enhancing the function of copy protection, in addition to the replacement of the signal of the horizontal synchronizing signal portion on the predetermined line as described above, the copy prevention technology of the method described in the conventional example is also applied. Needless to say, it does not matter.

In the video signal generation device described above, R
Although the example in which the waveform around the horizontal synchronization signal shown in FIG. 2 is recorded in the OM 4 is not limited to this, the ROM 4 stores the digital values corresponding to the black level and the sync chip level in FIG. Only the video signal of the picture portion from the memory 3 and the 2
The video signal may be generated by switching between the two digital values.

Further, it is needless to say that the same video signal can be generated by using an adder instead of the switching unit 5 and performing read control on each of the memory 3 and the ROM 4 so as not to output data except for a predetermined timing. No.

In the above description, an example in which the present invention is applied to a progressive scan signal having 525 horizontal scanning lines has been described. However, for example, other video such as an interlaced signal having 1125 horizontal scanning lines may be used. It goes without saying that it is applicable to signals.

The video signal generating apparatus according to the present invention is also applicable to a high image quality recording system or a digital recording system in which a picture portion is fetched into a memory for processing. Needless to say, this is an effective copy protection method.

[0040]

According to the first and fourth aspects of the present invention,
Only the waveform of the part immediately before the horizontal synchronizing signal in a specific line in the vertical blanking period of the video signal is changed,
Because it does not insert a special waveform with a large amplitude, there is little risk of its presence being detected.Also, since it adopts a waveform deformation near the horizontal synchronization signal, if you try to remove it, Depending on the accuracy of the circuit, the horizontal synchronizing signal itself is affected, and it is difficult to effectively remove the horizontal synchronizing signal as compared with the conventional system.

Further, claims 2 and 3 and claims 5 and 6
According to the invention described in (1), the reproduced image when the copy protection is performed can be made more unsightly, which is effective.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a playback device to which a video signal generation device according to the present invention is applied.

FIG. 2 is a diagram illustrating an example of a waveform around a horizontal synchronization signal.

FIG. 3 is a diagram showing waveforms around a vertical synchronization signal.

FIG. 4 is a block diagram showing a configuration of a circuit for generating a line pulse.

FIG. 5 is a timing chart for explaining a method of generating a line pulse.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Recording medium 2 ... Reproduction processing circuit 3 ... Memory 4 ... ROM 5 ... Switching device 6 ... D / A converter 11 ... Synchronization separation circuit 12 ... Delay means 13 ... Masking means 14 ... Counter 15 ... Clock generator 16 ... Comparison circuit

Claims (6)

[Claims] 1. A video information output unit that outputs video information of a picture portion in a video signal, a synchronization information output unit that outputs information related to a synchronization signal portion existing at regular intervals in the video signal, and the video information Generating output means for generating and outputting the video signal from the video information from the output means and information on the synchronization signal portion from the synchronization information output means, and a predetermined line in a vertical retrace period of the video signal A video signal generating apparatus, further comprising means for providing a falling edge from the black level of the video signal toward the synchronization leading edge level immediately before the horizontal synchronization signal in the above. 2. The video signal generation device according to claim 1, wherein the predetermined line is a plurality of lines that do not exist two consecutive lines in the vertical blanking period. 3. The video signal generation device according to claim 1, wherein the falling edge exists only in a part of frames or fields of the video signal. 4. A method for outputting video information of a picture portion in a video signal, outputting information on a synchronization signal portion present at regular intervals in the video signal, and outputting the information on the video information and the information on the synchronization signal portion. In the video signal generation method for generating the video signal based on the video signal, a falling edge from the black level of the video signal to a synchronization leading edge level is inserted immediately before a horizontal synchronization signal in a predetermined line in a vertical retrace period of the video signal. A video signal generation method characterized by the above-mentioned. 5. The video signal generation method according to claim 4, wherein the predetermined line is a plurality of lines that do not exist two consecutive lines in the vertical blanking period. 6. The video signal generating method according to claim 4, wherein the falling edge exists only in a part of frames or fields of the video signal.