DE19738350A1 - Inserting code signal into audio-video data signal - Google Patents

Abstract

The method involves determining a reference point in the data signal, determining predetermined code points based on the reference point, and inserting the code based on the predetermined code points. The reference points may be time points or reference addresses.- DETAILED DESCRIPTION - An apparatus for inserting a code signal is also claimed

Description

The present invention relates to a front direction and a method for inserting and recovering an identifier in data signals, for example in audio / Video signals, while maintaining the existing data form mattyps.

In particular, the present device or the present method achieved that an identifier in Form of numbers and letters BCD or ASCI coded in digital music or video sequences are stored can without reducing the sound quality or image quality perceptible extent to the human ear or eye Reduce. The method can be applied to currently existing Au dio and video formats such as z. B. in conventional CD Players find application to be used without the best change existing data format.

In conventional devices or methods for add inaudible additional signals to data signals according to DE 195 39 538 A1, for example, the audio signal transformed into a sequence of frequency spectra, the Additional data in the vicinity of certain spectral ranges to be added. The disadvantage of such conventional Lichen devices or methods, however, that the structure is relatively complex and therefore expensive. Furthermore, such labeling with additional information rela tiv easily bypassed, or the identifier from the audio signal can be deleted when the respective procedure analy siert and the frequency domain transformation is recognized.  

Particularly due to the worldwide networking of Computer systems through, for example, the Internet and that increasing supply of services and goods (audio / Video files) over such networks there is the special Be data files such as pieces of music, Video sequences and pictures, immediately before the remote data transmission, e.g. B. by Internet download, with a Se number and the name of the data recipient.

If this also means that the respective data files cannot be prevented, so enable If such a label does the reverse ver following pirated copies, as well as displaying the lawful Buyer when playing with appropriately equipped how dergabgeräte.

The invention is therefore based on the object Device and a method for inserting or recovering to create an identifier in a data signal in which the quality of the data signal in one for human Area that is not perceptible is changed, and the Data signal an almost undecodable identifier is shaped.

This object is achieved by the in Pa Measures 1, 9, 14 and 19 specified measures solves.

In particular by specifying a reference time tes in the data signal to be processed and the subsequent one Set predetermined identifier times that are at any time in the data signal, and where the identifier instead of the original music If values are inserted, an identification of Data signals such as audio, video and image si gnalen, in which the quality of the reproduced signals  not perceivable in one for the human sense organs range. In addition to those for tracing Pirated useful data such as serial number and name of the Data recipient can also add more data to the Data signal can be inserted, such as the title and interpreter of a piece of music or any other Da Up to 800 times can be played per minute be stored in the piece of music.

According to the definition of the predetermined th identification times by a predetermined algorithm mus, for example, a deterministic random gene nerator, which creates irregular spacing for the identifier result. This results in an extremely difficult coding algorithm to be deciphered, which is why a Remove the imprinted identification data, such as the serial number and the name of the data recipient, neither found can still be deleted.

On the receiver side, a device or method can be used ren are designed to recover the identifier, that, for example, in a special playback device (e.g. a CD player, multimedia PC, etc.) during the Ab playing the piece of music the serial number, the title and the artist can be shown in a built-in display can. There is even the possibility of the text of a Song in such a display device ben.

The invention is described below with reference to an embodiment approximately example with reference to the drawing wrote.

Show it:  

Figure 1 is a schematic representation based on the method and apparatus for inserting and recovering an identifier in a data signal is described.

Fig. 2 is a graphical representation of an analog audio signal;

FIG. 3 shows a graphical representation of the digitized audio signal according to FIG. 2;

FIG. 4 shows an enlarged representation of the curve signal according to FIG. 3 at time t ₁ before coding;

FIG. 5 shows an enlarged representation of the curve signal according to FIG. 3 at time t ₁ after coding;

Fig. 6 is a schematic view of an apparatus for inserting the identifier; and

Fig. 7 is a schematic representation of a device for recovering the identifier.

Fig. 1 shows a schematic representation for He elucidating the device and the method for inserting or recovering an identifier in a data signal.

The reference numeral 1 designates an encoding of the audio signal in the form of a sine wave. However, this data signal shown here in the form of a sine can be any analog audio, video or image signal. The reference numeral 2 designates a device for inserting an identifier as it is inserted into the analog data signal (audio signal), for example in the form of a serial number, the name of the data receiver, the title and the artist of the piece of music. The device 2 for inserting the identifier outputs the digital data signal 3 with the identifier superimposed therein to a transmission encoder 4 . In such transmission encoders, data backup or error coding necessary for data transmission is carried out in order to prevent data loss during transmission on the network. The network can be, for example, an internet environment 6 with which the data file (audio file) can be sent to any place in the world. On the receiver side, a corresponding to the transmission encoder 4 Übertragungsdecodie rer 7, with which the data can be recovered and occurred transmission error is corrected to who. The digital signal 10 thus recovered corresponds to the digital signal 3 output on the transmission side and can be reproduced immediately after D / A conversion. There is no audible or visible deterioration in the quality of the reproduced signal.

Furthermore, in a device for recovering the identifier, the digital signal can be processed in such a way that the identifier written in at the predetermined locations is read out and can be displayed. The device for recovering the identifier will not be present on the receiver side in most cases, but will only be replaced by a normal D / A converter, which gives the analog audio file 9 , which still has the peaks caused by the identifier.

Since the discrete ampli changes or amplitude peaks compared to the ma ximal amplitude value of the data signal (audio signal) very are low, the sound quality for the human ear not affected. For example, the digitali audio signal on a CD is only 0.04% of the maximum Number of amplitude values changed, with a single amplitude value to be changed by a maximum of 0.06% of the maxi paint amplitude value is changed. Nevertheless, at unauthorized duplication of the so obtained Piece of music or audio files copied the identifier, which is why  traceability to the original owner possible becomes.

Even if this will result in the production of pirated copies cannot be prevented immediately, nevertheless the possibilities for tracing pirated copies significantly improved.

Fig. 2 shows as a preferred embodiment for a frame to be encoded data signal a pure sine wave as an analog audio signal.

The sine shown in FIG. 2 is converted into a digital signal in the digitization according to the A / D converter method used in each case, as shown in FIG. 3. The digitized Audiosi signal corresponds essentially to the analog signal shown in FIG. 2, but with a higher resolution or enlargement of the curve signal, a staircase function would be visible.

The method for inserting or recovering an identifier in a data signal is described below with reference to FIGS. 3 to 5.

First of all, a reference time t _{s is defined} in the data signal in a digitized data signal, which can represent a sine in accordance with FIG. 3. More specifically, in the audio signal, video signal or an image signal having a certain data length, a certain data value is set as a reference value. Here, a reference time t _s corresponds with a corresponding data location or storage location in the respective data file, ie a specific reference time t _s is assigned a specific reference address in the data file.

The number of the respective storage locations depends on the ver averted A / D conversion methods and in particular from the sampling frequency used. More specifically, it increases Number of digitization steps with the sampling frequency, which also increases the number of storage spaces required ze increased.

To determine the reference point in time t _s , a threshold value decision can be carried out, for example, in which the data signal for the first time exceeds a certain amplitude value A or a digital value U _min . Such a threshold value decision can be implemented, for example, by a comparator that compares the data value of the signal that is currently present with a predetermined minimum value. If the data value currently read out reaches the predetermined target value U _min , then the reference time t _s or the reference address for the respective data file is used. Instead of the threshold value decision for determining a reference point in time t _s , decision options can also be used which check a large number of characteristic properties of the respective data signal. This can be, for example, several threshold values or the slope of the data signal. An incorrect determination of the reference time t _s can thereby be avoided.

On the basis of the reference time t _s or the associated storage location in the data file, predetermined identification times or identification storage locations (addresses) are now determined as a function of the reference time t _s or reference address described above. Each storage location of the data file can be defined by an address in relation to the reference storage location. The determination of the predetermined identifier times t ₁ or the identifier addresses is preferably carried out by a coding algorithm which is not known to the receiver and which is in the data file at arbitrary and preferably uneven times t ₁ , t ₂ , t ₃ . . . t _n releases the data values of the data signal for inserting the identifier. Preferably, the identification algorithm is represented by a deterministic random number generator which defines the identification points t _i differently for each different data file as a function of the value of the reference point t _s and which makes the identification times t _i or identification almost impossible for the receiver - Decrypt addresses in the data file.

After the determination of the predetermined identification times t _i or the identification addresses as a function of the reference time t _s or the reference address, the identification is inserted. The identifier consists, for example, of a large number of digits and letters that are BCD- or ASCI-coded at the identification times t _i or identification addresses.

The insertion of the identifier is described below with reference to FIGS. 4 and 5.

FIG. 4 shows an enlarged view of the data signal according to FIG. 3 in the vicinity of the time t ₁ , the signal according to FIG. 4 being in the state before coding. According to FIG. 4, the digital data signal has the data value U (t ₁ ) or U ₁ at the identification time t ₁ or at the associated identification address. In the immediately following sampling time t ₁ +1 or in the memory space immediately following it, the data value of the data signal has the value U (t ₁ +1).

FIG. 5 shows an enlarged view of the data signal according to FIG. 3 in a state after the coding or after the insertion of the identifier. The BCD or ASCI coded identifier consists of a plurality of identifier values W _i , which are inserted into the data signal at a respective identifier time t _i or the respective identifier address. Here, the reference symbol W _{1 represents} a byte of the information or identifier to be coded, which is stored at the identification time t ₁ .

Specifically, the identification value W ₁ is inserted by adding the data value U ₁ to the identification time t ₁ with the identification value W ₁ . This new data value U '(t ₁ +1) = U ₁ + W ₁ is stored in the immediately following sampling time t ₁ +1 or immediately below the memory address. Since the amount of the identification value W _{1 is} very small in comparison to the respective data value of the data signal, there is only a very slight change in the data value which occurs during playback after D / A conversion in the case of audio, video and Image signals cannot be detected by the human sensory organs and therefore do not cause a deterioration in the quality of the signal for humans. Nevertheless, the changed data value can hardly be found when analyzing the data signal, since it is lost in the data signal. The recovery of the identifier is therefore only possible with knowledge of the reference point in time and the special identification algorithm that defines the identification points in time t _i as a function of the reference point in time t _s .

To further improve the insertion process, the identification values W _{i are} preferably inserted according to the following scheme.

If the identification time t _{1 is,} for example, on a rising edge of the data signal, then the identification value W _{1 is added} to the data value U ₁ and is stored in the subsequent time t ₁ +1 as data value U '(t ₁ +1). If, on the other hand, the identification time t _{2 is} on a falling edge of the data signal, the identification value W _{2 is} subtracted from the data value U _2, which is stored in the subsequent sampling time t ₂ +1 as the value U '(t ₂ +1) .

This results in a particularly adapted insertion of the identification values W _i into the data signal, as a result of which audible or visible disturbances in the reproduction of the analog data signal can be effectively prevented.

The respective identifier value W _i is thus stored as U '(t _i +1) = U (t _i ) ± W _i in the subsequent time (t _i +1).

According to a preferred embodiment, the decision as to whether the identifier value W _i to the data value U _i ad diert or subtracted will also be made dependent on whether the data value U _i in the positive or in the negative half cycle of the data signal is. If the identifier _i at time t, for example, in the positive half cycle of the data signal so the identifier value W _i to the data value U _i is subtracted. On the other hand, the identifier value W _{i is added} to the data value U _i when the identifier time t _{i is} in the negative half-wave. In this way it can be ensured that the identification values W _i to be encoded can also be displayed if a data value U _i assumes the maximum or minimum amplitude value or data value.

The recovery of the identifier so registered takes place in a corresponding manner.

First of all, the reference data value U _min is recorded in a received data file in the same way as it was defined in the insertion method described above. In other words, knowing the specific threshold value or the various threshold values or the slope of the data signal, the reference data value or the reference address can be recovered from the digitized data file. Then, with knowledge of the identification algorithm described above, the identification times or identification addresses of the data signal or the data signal of the data file are recovered, as a result of which exactly the times or addresses are obtained at which the identification values W _i were written . Now, in accordance with the insertion method, the amount of the respective identification value W _{i is} determined again by subtracting the data value at the time t _i from the data value at the time t _i +1 and the identifier is output, for example, on a display device.

The recovery corresponds essentially to that Insert the identifier, which is why it is not here is further described.

FIG. 6 shows a schematic illustration of a device for such an identification insertion. The reference numeral 11 here designates an analog / digital converter for digitizing the analog data signal 1 . The data signal thus digitized can, for example, be stored in a storage device 12 as a data file (audio / video file). A comparator device 13 compares the data values of the data file stored in the storage device 12 with a predetermined threshold value U _min and thereby determines, for example by first exceeding this threshold value U _min, the reference time t _s or the associated reference address. An identifier address determining device 15 now determines the corresponding identifier times t _i or identifier addresses more as a function of the reference time t _s thus determined or the associated reference address. Subsequently, an identifier sequence is divided into a plurality of individual identifier values W _i by an insertion device 14 and written to the corresponding identifier addresses in accordance with the method described above. Is the identifier completely in the respective data values of the data file has been written, the thus encoded data file can be supplied to the transmission encoder and transmitted catcher 4 via an external network such as the Internet to a Emp.

The data file coded in this way is received at the receiver therefore decoded by the transmission decoder and the pre Direction for identification recovery fed.

Fig. 7 shows a schematic view of the device for device recovery. The identification recovery takes place in a similar manner to the insertion of the identification. Reference number 16 denotes a storage device for the received data file. A comparator 17 determines in the same way as the comparator 13 a reference address or a reference time t _{s of} the received data signal. On the basis of the reference address determined in this way, the identification addresses or identification times t _{i are} determined using the same recognition algorithm as in the insertion method. The identifier is then recovered in a manner corresponding to the insertion method at the identifier addresses or identifier times and output as an identifier on a display device.

Such a device for identification recovery can for example in a CD player or a multime slide computer can be implemented, whereby ei nes such coded signal, for example, the buyer Serial number, title, artist and the text of the Song can be displayed.

The device described above and the Ver drive to insert or recover an identifier on a digitized data signal, however it can also an analog data signal in a corresponding manner be provided with an analog identifier.

Claims (26)

1. Method for inserting an identifier in a data signal, in particular audio / video signal, with the steps:
Establishing a reference point (t _s ) in the data signal,
Setting predetermined identification points (t _i ) as a function of the reference point (t _s ), and
Insert the identifier depending on the predetermined identifier points (t _i ). 2. The method according to claim 1, characterized in that the reference points are reference times (t _s ) or reference addresses and the identification points are identification times (t _i ) or identification addresses. 3. The method according to claim 2, characterized in that the data signal is a digitized signal,
the reference point (t _s ) and the identification points (t _i ) correspond to the sampling times of the A / D conversion, and
the insertion of the identifier corresponds to a change in a data value (U (t _i )) as a function of the respective identifier point (t _i ). 4. The method according to any one of claims 1 to 3, characterized in that the determination of the reference point (t _s ) by a threshold value detection of the analog amplitude denwert or digital data value of the data signal follows. 5. The method according to any one of claims 1 to 4, characterized in that the predetermined identification points (t _i ) are set by an algorithm. 6. The method according to claim 5, characterized indicates that the algorithm has a deterministic approach case generator. 7. The method according to claim 6, characterized in that the random generator generates the identification points (t _i ) depending on the reference point (t _s ) for each data file differently. 8. The method according to any one of claims 2 to 7, characterized in that the identifier has a plurality of digital identifier values (W _i ), which immediately after the respective identifier time (t _i ) instant (t _i +1) be added to the data value (U _i ) at the identification time (t _i ) of the data signal. 9. The method according to claim 8, characterized in that the digital identifier value (W _i ) is added to the data value (U _i ) when the identifier time (t _i ) is on a negative curve signal part of the data signal. 10. The method according to claim 8, characterized in that the digital identifier value (W _i ) is subtracted from the data value (U _i ) when the identifier time (t _i ) is on a positive curve signal part of the data signal. 11. The method according to claim 8, characterized in that the digital identifier value (W _i ) is added to the data value (U _i ) when the data values immediately preceding the identifier time (t _i ) are increasing, and the digital identifier value ( W _i ) is subtracted from the data value (U _i ) if the data values immediately preceding the identification time (t _i ) are in descending order. 12. A method for recovering an identifier in a data signal, comprising the steps:
Detection of a reference point (t _s ) in the data signal,
Determining predetermined identification points (t _i ) depending on the reference point (t _s ) and a decoding algorithm, and
Recovery of identification values (W _i ) as a function of the predetermined identification points (t _i ). 13. The method according to claim 12, characterized in that the reference points are reference addresses or reference times (t _s ) and the identification points are identification addresses or identification times (t _i ). 14. The method according to claim 13, characterized in that the detection of the reference point (U _min ) is carried out by comparison with a predetermined value. 15. The method according to any one of claims 12 to 14, characterized in that the decoding algorithm a coding algorithm corresponding to the insertion method corresponds. 16. The method according to claim 15, characterized records that the decoding algorithm has a deterministic represents random generator. 17. The method according to any one of claims 13 to 16, characterized in that the recovery of the respective identifier values (W _i ) by subtracting the respective identifier data value (U _i ) from an immediately succeeding the identifier data value (U (t _i + 1)) takes place. 18. Device for inserting an identifier into a data signal with:
a reference address detection device ( 13 ) for detecting a reference address in the data signal,
an identifier address determining device ( 15 ) for determining identifier addresses depending on the reference address, and
an insertion device ( 14 ) for inserting the identification in dependence on the identification addresses. 19. The device according to claim 18, characterized in that the reference address detection device ( 13 ) has a comparator which compares an instantaneous data value (U _i ) with a predetermined data value (U _min ). 20. The device according to claim 18 or 19, characterized in that the identifier address determining device ( 15 ) sets the respective identifier addresses by egg NEN algorithm. 21. Device according to claims 18 to 20, characterized in that the insertion device ( 14 ) adds the data value (U _i ) of the respective identifier address to the identifier value to be written (W _i ) and inscribes it in the next address when the data value ( U _i ) is in the negative curve signal part of the data signal, while the identifier value (W _i ) to be inserted is subtracted from the data value (U _i ) when the data value (U _i ) is in the positive curve signal part of the data signal. 22. Device according to patent claims 18 to 20, characterized in that the insertion device ( 14 ) subtracts the identifier value (W _i ) to be inserted from the data value (U _i ) of the respective identifier address if the immediately preceding data values are descending while they are to be inserted Identifier value (W _i ) is added to the data value (U _i ) of the respective identifier address if the immediately preceding data values are increasing. 23. Device for recovering an identifier in a data signal
a reference address detection device ( 17 ) for detecting a reference address from the data addresses of the data signal,
an identifier address determining device ( 18 ) for determining respective identifier addresses depending on the reference address, and
an identifier recovery device ( 19 ) for recovering the identifier depending on the identifier addresses. 24. The device according to claim 23, characterized in that the reference address detection device ( 17 ) has a comparator which compares the data values of the respective data addresses with a predetermined data value and the identifier address determining device ( 18 ) the respective identifier addresses by a decoder Algorithm of the insertion device corresponding decoding algorithm is determined. 25. The device according to claim 23 or 25, characterized in that the identifier recovery device ( 19 ) has a subtractor that the data value (U _i ) in the respective identifier address from the data value (U (t _i +1)) subtracts the next data address and outputs the amount as identifier value (W _i ). 26. The device according to claim 23 to 25, characterized by a display device with which the identification values (W _i ) recovered from the identification recovery device ( 19 ) are displayed.