CN1069381A - A kind of anti-copy video tape recording method and device - Google Patents

Abstract

A kind of anti-copy video tape recording method and device, when making the video program band, in vision signal to be recorded, be superimposed with greater than line width, be higher than the white level signal of standard line blanking level, during the white level signal, remove line synchronizing signal discontinuously, and add the disturbing pulse of upsetting the work of video tape recorder agc circuit in the appropriate location of vision signal.The video reproduction of made program band is normal, then can not normally watch after the reprint, loses commercial value.This method and device, principle is simple, and is effective, and it is few to increase cost, is convenient to promote, and is applicable to various model video tape recorders.

Description

A kind of anti-copy video tape recording method and device

The invention belongs to video tape encryption technology field, relate to a kind of method for recording and device of new anti-copy video tape.

Along with popularizing of home video tape recording, the illegal reprint of video program band, sale become a problem demanding prompt solution.There are many producers and company to study in this respect, but do not see and obtain desirable effect.A kind of magnetic tape enciphering method of upsetting video tape recorder automatic gain compensation function is provided in the patent application of the patent No. for CN88107670, find through practical application, under the measured situation of master master tape matter, the video program band that adopts this method to record, even video amplitude decay 6～8dB after reprint, picture quality can't obviously reduce, and does not also influence normally and watches, can not reach to prevent that effectively the video program band is by the purpose of illegal pirate recordings.

The object of the present invention is to provide a kind of section directory image-tape that can effectively prevent by the method for recording and the device of illegal pirate recordings, institute's recorded program video tape, video reproduction is watched on common record (putting) camera, and picture quality is identical with the general programs video tape; And the replica cassette after common video tape recorder pirate recordings, the playback time image can't normally be watched, loses commercial value.

Basic design of the present invention is: when recording the video program band, the appropriate location superposition in vision signal to be recorded greater than line width, be higher than the white level signal of standard line blanking level, and during white level signal superposition, remove line synchronizing signal discontinuously; Take measures (as adding the disturbing pulse of upsetting agc circuit work) again, make the section directory image-tape of being recorded after common video tape recorder pirate recordings, the video amplitude that replica cassette is recorded drops to below 2/3 of original signal amplitude.Recorded program band like this, though playback time line synchronizing signal during white level interference signal superposition cuts in and out, lose to some extent, according to the separated in synchronization principle, when not having line synchronizing signal the clipping level of the capable synchronizing separator circuit of television set will on move, but video amplitude is enough big, synchronous head is bigger apart from amplitude difference between the white level, it is synchronous can not cut out the white level effect of signals, and video reproduction is normal.This program band is after common video tape recorder pirate recordings, video amplitude drops to original signal below 2/3, playback time is during white level interference signal superposition, synchronous head diminishes apart from amplitude difference between the white level, will cut out the white level signal, for field sync signal, caused jitterbug by the television set erroneous judgement, can not normally watch.

Specified below in conjunction with embodiment and accompanying drawing.

Fig. 1 is equipped with figure for the device that adopts method for recording of the present invention.Fig. 2 is the electric functional-block diagram of video-encryption device.Fig. 3 is the circuit theory diagrams of the white level signal generator of video-encryption device.Fig. 4 is a signal waveforms corresponding among Fig. 1,2,3.

In Fig. 1, master master tape player 1 adopts common record (putting) camera, compare with general section directory image-tape recording system, increased video-encryption device 2, it is sealed in before the video input of duplicating video tape recorder 3, duplicate video tape recorder 3 and will can not reduce amplitude to guarantee institute's recorded program band vision signal according to the corresponding repacking that requires of video-encryption device owing to the anti-measure of duplicating on video-encryption device 2 superpositions.In the present embodiment, the disturbing pulse superposition is being treated recorded video signal field black-out intervals, only need remove during repacking to duplicate video tape recorder luminance signal agc circuit and get final product.Video-encryption device 2 can be directly installed on and duplicate in the video tape recorder 3, also can make an equipment separately, duplicates video tape recorder so that control many simultaneously by video distributor.

In Fig. 2 and Fig. 3, A be master master tape player 1 output treat the recorded video signal, B exports to the encrypted video signal that duplicates video tape recorder 3 after encrypting through video-encryption device 2.Video-encryption device 2 is made up of synchronizing separator circuit 5, white level signal generator 7, white level signal superposer 4, disturbing pulse generator 8, disturbing pulse superposer 6.Vision signal A to be recorded takes out line synchronizing signal H, field sync signal V through synchronizing separator circuit 5, send into 10 pin (counting), 11 pin (zero clearing resets) of the counter IC1 of white level signal generator 7 respectively, field sync signal V delivers to 10 pin (counting) of counter IC4 simultaneously, and delivers to disturbing pulse generator 8; The count signal of IC1 output (this example is got the output of 4,6,9 pin) is sent into the input (this example is got 11,12,13 pin) of AND circuit IC2, seizes 12 pin of sending into monostable trigger-action circuit IC3 with computing from 10 pin output I signal through patrolling; Time capacitor C1 is connected between 14,15 pin of IC3, and timing resistor device R1 connects working power U and 14 pin, and working power U is from 11,13 pin input IC3; The 11 pin ground connection of IC4.Vision signal A and from the white level signal D of 10 pin of IC3 output, together send into white level signal superposer 4 from the capable synchronous control signal E of 6 pin (can the select output pin) output of IC4 and obtain vision signal F according to the counting needs, disturbing pulse signal G superposition in disturbing pulse superposer 6 of F signal and 3 generations of disturbing pulse generator duplicates video tape recorder 3 for vision signal B exports to.The white level signal generator is made up of row coincidence counter IC1, field synchronization counter IC4, AND circuit IC2, monostable trigger-action circuit IC4 and peripheral component, IC1 and IC4 can use the CD4040 integrated circuit, IC2 can use the CD4073 integrated circuit, and IC3 is the CD4098 integrated circuit.Monostable circuit timing resistor device R1 and capacitor C1, the width of decision monostable output pulse, the desirable 10K Ω of R1 here, the desirable 0.15 μ F of C1.As can be seen from Fig. 4, the superposition position of D signal and width all are selectable, preferably change at the end of picture intelligence.In the present embodiment, the white level signal D of institute's superposition is positioned at before the field synchronization leading Eq pulse in vision signal A, B, F, the position (image bottom) of last 10 row of picture intelligence, this is that image is normal not to show that (last 10 row of general television receiver video signal do not show substantially in order not influence as far as possible, or all do not show), width is 9 row.The starting point of D signal is the starting point by I signal, and the count output signal of coincidence counter IC1 is selected at once.The end point of D signal (being the width of D signal) is by the output decision of the determined time constant control of R1 and C1 monostable trigger-action circuit IC3.In F and B signal, whether still keep line synchronizing signal (dotting among Fig. 4) during on the D signal superposition, by the E signal controlling, when the E signal is got low level, line synchronizing signal is cancelled, and (shown in E ' signal among Fig. 4) line synchronizing signal kept when the E signal was got high level.The variation of E signal level is determined the result of the field sync signal V counting of output and the output pin of being got (this example is got 6 pin) by field synchronization counting circuit IC4, setting E signal period of change in this example is 0.4 second (promptly 10 high level, 10 low levels back and forth change), for convenience of explanation, represent respectively that with E and E ' signal the E signal gets the situation of low, high level (because it is corresponding with other signals to be difficult to draw 20 field signals) in this respectively here.The G signal is got 11 of the pulses of the about 20ms of width in this example, and on the F signal, field sync signal V is controlled as time reference in the time of its superposition at the field blanking interval superposition.Field sync signal is taken out behind synchronizing separator circuit 5, and certain time-delay is arranged, and therefore lags behind the field synchronization of signal A, F, B.

The present invention has the following advantages:

1, adopt this method recorded program video-tape, the video reproduction quality is good, and the replica cassette after common video recorder pirate recordings, during video reproduction jitterbug serious, can't normally watch, lose commercial value, can prevent effectively that the section directory image-tape is by reprint.

2, adopt the record device of this method, principle, simple in structure, it is few, easy to utilize to increase cost.

3, anti-pirate recordings all has effect preferably to the video tape recorder of various models in the present invention.

Claims (3)

1, a kind of anti-copy video tape recording method, when making the video program band, appropriate location in vision signal adds the disturbing pulse of upsetting the work of video tape recorder agc circuit, it is characterized in that, in vision signal to be recorded on the superposition greater than line width, be higher than the white level signal of standard line blanking level, and during the white level signal, remove line synchronizing signal discontinuously.

2, a kind of device that adopts anti-copy video tape recording method as claimed in claim 1 is by master master tape player 1, video-encryption device 2, duplicate video tape recorder 3 and form; The circuit of video-encryption device 2 is by synchronizing separator circuit 5, disturbing pulse generator 8, disturbing pulse superposer 6 is formed, it is characterized in that, the circuit of video-encryption device 2 has increased white level signal generator 7 and white level signal superposer 4, white level signal generator 7 is by row coincidence counter IC1, field synchronization counter IC4, AND circuit IC2, monostable trigger-action circuit IC3 and peripheral component are formed, the connection of partial circuit is as follows: vision signal A to be recorded takes out line synchronizing signal H through synchronizing separator circuit 5, field sync signal V, send into 10 pin (counting) of the counter IC1 of white level signal generator 7 respectively, 11 pin (zero clearing resets), field sync signal V delivers to 10 pin (counting) of counter IC4 simultaneously, and delivers to disturbing pulse generator 8; The count signal of IC1 output is sent into the input of AND circuit IC2, send into 12 pin of monostable trigger-action circuit IC3 from the 10 pin output I signal of IC2, time capacitor C1 is connected between 14,15 pin of IC3, and timing resistor device R1 connects working power U and 14 pin, and working power U is from 11,13 pin input IC3; The 11 pin ground connection of IC4, vision signal A and together send into the superposer 4 of white level signal from the white level signal D of 10 pin of IC3 output, from the capable synchronous control signal E of the 6 pin output of IC4, obtain vision signal F, disturbing pulse G signal superposition in disturbing pulse superposer 6 that F signal and disturbing pulse generator 8 produce duplicates video tape recorder 3 for vision signal B outputs to.

3, the video tape device of recording as claimed in claim 2 is characterized in that, IC1 and IC4 adopt the CD4040 integrated circuit, and IC2 adopts the CD4073 integrated circuit, and IC3 adopts the CD4098 integrated circuit.

Images