MXPA01008530A - Embedding a first digital information signal into a second digital information signal for transmission via a transmission medium - Google Patents

Abstract

A transmitter is disclosed for transmitting a first and second digital information signal. Said first digital information signal comprises first frames having at least a first synchronization signal and a data portion stored in them. The transmitter processes the second digital information signal into subsequent second frames comprising blocks of information of the second digital information signal. Composite frames have been obtained by inserting a second synchronization signal and at least the data portion of the first frames into the second frames by using buried data techniques. Prior to inserting at least the data portion of the first frame into a second frame the first synchronization signal is stripped from the first frame. The sequence of composite frames is transmitted via the transmissionmedium.

Description

INCLUSION OF A FIRST SIGNAL OF DIGITAL INFORMATION IN A SECOND SIGNAL OF DIGITAL INFORMATION FOR TRANSMISSION VIA A MEDIO OF TRANSMISSION The invention relates to a transmitter for transmitting a first and second digital information signal via a transmission means, said first digital information signal comprises first structures having at least a first synchronization signal and a portion of data stored therein, the transmitter comprises: - input means for receiving the first and second digital information signal; - processing means for processing the second digital signal in second subsequent structures, said second structures comprising blocks of information of the second digital information signal; - means for combining signals to insert a second synchronization signal and at least the data portion of a first structure in a second structure of the second digital information signal in such a way that a combined structure is obtained; - output means for providing the combined structures to an output terminal in such a way as to obtain a combined signal to be retransmitted. The invention further relates to a receiver for receiving a combined signal from a transmission medium and for generating a first and a second digital information signal, to a record carrier obtained with the transmitter, when it is in the form of a recording device. information in a record carrier, and to a transmission method. _ The defined upstream transmitters and receivers are commonly known in the form of transmitters to transmit an MPEG encoding signal. The transmission systems usually use multiple layers. Synchronization is possible only through the use of synchronization patterns in these layers. However, these synchronization patterns in a system that has multiple synchronization patterns reduce transmission efficiency. For example, in DVD-Video synchronization patterns are used in system current layers ai as in the elementary stream layers. Only the synchronization pattern in the highest system layer is used for synchronization in the system comment. The synchronization patterns in the elementary currents are used for synchronization during the decoding of said elementary current. In addition, DAB uses synchronization patterns in the system current layer as well as in the elementary current layer. However, a decoder uses only one of the two. The invention helps to provide transmitters and receivers having a more efficient method of transmitting and receiving a first and a second digital information signal, wherein said first digital information signal comprises first structures having at least a second synchronization portion. The transmitter according to the invention is characterized in that the signal combining means is adapted to remove the first synchronization signal from said first stunts before inserting at least the data portion of the first structures into the second structures. The receiver according to the invention is characterized in that the receiver also comprises; - means for generating synchronization signals to generate a first synchronization signal; - means for combining signals to combine the first synchronization signal and the • minus the data portion of the first digital information signal to then obtain a first structure of the first digital information signal; - second output means for subsequently providing the first structures of the first digital information signal to a first output terminal to then obtain the first digital information signal. The invention is based on the following recognition. In for example a data channel hidden in a PCM signal any other information signal can be stored.

• In order to recover the information signal of said hidden data channel, the channel of Hidden data comprises structures where each structure has a synchronization signal. After detecting said synchronization signal, a structure of the hidden data channel can be retrieved from the PCM signal. If the information signal stored in the hidden data channel is an encoded signal comprising a sequence of structures each with a synchronization signal, for example a As the MPEG coding signal, said synchronization signal has to be recovered in a receiver that is capable of decoding said sequence of structures. However, if ? each structure in the hidden data channel comprises only one structure of the encoded signal, said synchronization signal in a structure of the encoded signal needs not to be transmitted, there said synchronization signal can be generated in the receiver each Once a structure is retrieved in the hidden data channel. So in a transmitter, before inserting a structure of the encoded signal in the hidden data channel the synchronization signal is removed from said structure. In a receiver the synchronization signal is generated and combined with the data retrieved from a structure of the hidden data channel to then obtain a structure of the encoded signal. To the By doing this, the data capacity necessary to transmit an additional signal comprising a sequence of structures is reduced. This reduction can be used to use less capacity in the PCM signal for the hidden data channel, resulting in a higher quality PCM signal. On the other hand, the extra data capacity in the hidden data channel, which was obtained by removing the synchronization signal can be used to transmit a less compressed data signal, normally being a better representation of the data signal.

These and other objects of the invention will be apparent and elucidated later with reference to the characterizations described in the following description of figures in which: Figure 1 shows a characterization of a transmitter according to the invention, Figure 2 shows a characterization of a receiver according to the invention, Figure 3 shows a structure of hidden data with header (header), Figure 4 shows the "descrambling" circuit, Figure 5 shows that the bits in the hidden data structure need to be inserted into the "unchaerising" circuit in a specific order; Figure 6 shows a CRC review diagram; Figure 7 shows a structure of stereo PCM samples 1152 corresponding to 192 F3 structures; Figure 8 shows a hidden data structure without spindle ( header), Figure 9 shows the distribution of the encoded MPEG2 audio data, the hidden data channel and the physical channel.

Figure 1 shows a characterization of a transmitter according to the invention. The transmitter has a first input terminal 4 for receiving a first digital information signal. Said first digital information signal comprises first structures. The first structures comprise at least a first synchronization signal and a data portion. The first digital information signal may be an MPEG encoded signal. The transmitter has a second input terminal 2 for receiving a second digital information signal. The second digital information signal is for example a normal CDDA signal (Compact Disc Digital Audio). The second digital information is provided to a processing unit 6. The processing unit 6 divides the second digital information signal into subsequent blocks of information. From the subsequent blocks of information the processing unit 6 generates subsequent second structures. In a preferential characterization the second digital information signal is a normal CDDA signal having PCM samples. Preferably, a second structure comprises samples PCM 1152. Each structure consists of sub structures PCM 3, each has samples PCM 384. It should be noted that the number of sub structures PCM 9, each has samples PCM 128, which are also suitable. The transmitter further comprises a synchronization generator unit 8 for generating a second synchronization signal. The second synchronization signal is provided to a signal combination unit 10. The combination unit 10 preferably makes use of hidden data techniques to determine a hidden data channel in the PCM samples of a second structure. By using hidden data techniques, the perceived S / N radio of the transmitted PCM signal, which comprises a hidden data channel in the least significant bits of the PCM samples, is approximately the same S / N radius of the original PCM signal . The combination unit 10 inserts the second synchronization signal in the hidden data channel. Preferably, the synchronization signal is inserted in the second structure in such a way that the structure starts with a synchronization pattern in both. least significant bits of his first samples PCL 6 L + R. The data to be stored in the hidden data channel is preferably inserted in the PCM L and R channel in a sample by means of an interleaved sample base. Figure 3 shows a characterization of a second structure. Every second structure starts with header information. The spindle information of each structure comprises the synchronization signal, the bit distribution of the sub structures 3 define the PCM bits belonging to the hidden data channel. In addition, the hidden data structure payload is an example of the least significant LSB bits of the PCM L + R samples, which are determined by hidden data techniques to be used to carry data bits from the hidden data channel. Figure 5 shows an example of how bits can be inserted into the hidden data structure. First, the head is stored alternatively in the LSB of the first left and right PCM samples 4 of the first substructure. Then, the data bits are inserted alternately into the payload of distributed hidden data. In Figure 4 the 3 LSB of the PCM samples of the channel Left and the 2 LSBs of the Right channel are distributed to store data. The figure in the boxes indicates the sequence in which the bits are stored in the payload of hidden data. The signal combining unit 10 is arranged to insert at least the data of a first structure into a payload of hidden data structure. First, the first synchronization signal is removed from the first structure by means of unit 12. Subsequently, before writing the data portion of the first structures in the hidden data structure payload, the data portion of the first structure is randomized. structure. Randomizing an outbreak of errors in the hidden data structure payload will not immediately result in incorrigible errors in the hidden data channel data. Finally, the signal combining unit 10 is arranged to store a CRC-16 word in the last 16 bits of the hidden data structure payload for error detection purposes, therefore, the data bits inserted in The hidden data channel is supplied through an LFSR (Linear Feedback Change Record) with for example 0x8005 polynomial. In the case that there is no capacity in the PCM samples for a hidden data channel, only the head information is inserted in a second structure. The operation of the transmitter is as follows. The PCM structure consists of 3 sub structures each with 384 PCM samples. The 1152 PCM samples in a PCM structure represent a length of time that exactly matches the length of the MPEG-2 Audio Layer II structure. In the IEC-61937 format the first 16 bits of an MPEG Audio structure are unique to the CD Envelope application (OxFFFC, 12 sync bits + ID = mpeg - 1 + Layer = II + protection - used). Since the length of time of a PCM structure is equal to the time length of an MPEG structure, the first 16 bits of an MPEG structure do not need to be transmitted. In a receiver said 16 bits have to be placed before the hidden data extracted and decoded. In addition, a preamble consisting of two synchronized words, an identification word and a payload length have to be placed before the MPEG Audio structure and finally the IEC structure has to be filled with zeros. The transmitter receives the PCM CDDA samples and generates subsequent structures each with 1152 PCM samples. The available capacity for a hidden data channel is determined. Subsequently, the transmitter receives the MPEG audio structure and removes the first bits of said structure. The remaining bits of said structure are randomized and a CRC word is determined for the remaining bits. To obtain the combined signal first, the header information is inserted into the LSB of the first PCM samples in a structure. Second, the randomized bits are inserted into the hidden data channel payload. Finally the word CRC is inserted in the last 16 bits of the payload of hidden data structure. Then the combined signal obtained is transmitted via a transmission medium. The hidden data channel is preferably used to transmit extra audio content within the 16-bit audio PCM data on a normal Audio CD. This extra audio content is preferentially compressed according to the Audio MPEG standard. Since the first 16 bits of an MPEG Audio Structure are unique to the CD Envelope application, they are not transmitted. In a CD envelope decoding apparatus comprising a receiver which will be described below these 16 bits are placed in front of the extracted bits of the hidden data channel stored in the PCM data. Figure 2 shows a characterization of a receiver to redirect a combined signal and generate a first and second digital information signal therefrom.

The combined signal comprises combined structures. A combined structure has a second synchronization signal. The receiver has an input terminal 20 to redirect the combined signal. The combined signal is provided to a detection unit 22 and unit 24. The detection unit 22 is prepared to detect a second synchronization signal and generate a detection signal in response to a second synchronization signal. The detection signal is provided to a control input of the unit 24. The unit 24 is prepared to recover a combined structure of a combined signal in response to the detection signal. The combined structures are provided to a first extractor unit 26 and a second extraction unit 28. The first extractor unit 26 is prepared to extract at least one portion of data from a first structure of the first digital information signal of a structure. combined The data portion of a first structure is provided to a signal combining unit 32. The second extraction unit 28 is prepared to extract at least a part of the second digital information signal from a combined structure in such a way as to obtain a second structure of the second digital information signal. The subsequent second structures, which form the second digital information signal, are provided to the output terminal 30. The redismer further comprises a synchronization signal generator unit 34. The synchronization signal generator unit 34 is prepared for generate a first synchronization signal. The first synchronization signal is provided to the signal combination unit 32. The signal combining unit 32 is prepared to combine the first synchronization signal and at least the data portion of a first structure in such a way as to obtain the first structure of the first digital information signal. The first subsequent structures are provided to the output terminal 36. The first subsequent structures form the first digital information signal. The above-described receptor functions as follows. The combined signal is redunded at the input terminal 20. A transmitter as described above generates the combined signal. The combined signal is a CDDA signal having right and left PCM samples. The CDDA signal comprises structures as described in Figure 3. The CDDA signal comprises a hidden data channel. In order to recover the hidden data of the CDDA signal each structure comprises spindle information. The header information comprises a second synchronization signal. The second synchronization signal is found in this characterization in the two least significant bits of the first samples PCM 6 L + R of each structure. However, other ways of inserting the second synchronization signal are possible, for example in the least significant bit of the first samples PCM 12 L + R. The synchronization signal detection unit 22 detects the second synchronization signal and generates a detection signal in response thereto. Unit 24 retrieves the combined structures of the CDDA signal under control of the detection signal. A caraderization of a structure is described in Figure 3. The second extraction unit 28 receives the second structures to generate the second digital information signal. Since a hidden data channel is used in this characterization, there is no need to extract the unmodified bits of the original signal from the PCM samples of the second stage. In case the LSB of each PCM sample is used to carry the first digital information signal, these bits will introduce audible noise. In order to reduce the audible noise, the MSB of the PCM samples have to be extracted from the second structures. The synchronization signal generator unit 34 generates a first synchronization signal. In the event that the first digital information signal is an MPEG-2 Audio Layer II signal, the first 16 bits of each station are unique for the CD Envelope application (OxFFFC, 12 sync bits + ID = mpeg-1 + Layer = ll + protection = used). In addition, a preamble consisting of two synchronized words, a word of ideptification. The first synchronization signal comprises at least this information. The first extraction unit 26 extracts the head information from the second conditions. The spindle information comprises together with the synchronization signal information the bit distribution of the sub-strings. The bit distribution defines the bits of the PCM samples that belong to the hidden data channel, hence the hidden data payload. Next, the unit 26 extracts the hidden data from the second structures. Preferably, the hidden data bits are written randomly in the hidden data channel. Figure 4 shows a caraderizactón for desleatorizing the hidden data bits. The drcuito comprises a variety of delays and exdusive ORs. The delays perform a function of bit delay. The reference tn represents bits of hidden data entered n and Sp representing the descrambler bit n. The cubicle described in figure 4 performs the following operation: out = z [16J? z [14]? z [3j? z [1]? z [0], where "?" is the logical exclusion or operator and z [n] is the extracted bit n bits backward. At the beginning of a new structure the z-state has to be inidalized with all the ones. The descrambler data of a structure is provided to the combiner unit 32. The first extractor unit preferably comprises a CRC review unit. A diagram of said cubicle is described in figure 6. The last 16 bits of the hidden data contain a word CRC-16 for error detection purposes. Each bit of hidden desalted data, except for the last 16, is supplied through an LFSR (Registry of Change of Linear Feedback) with 0x8005 polynomial, as described in Figure 6. The final state of the LFSR has to be compared with the word CRC-16 of hidden data. If these two words are not the same, a transmission error has occurred. The combining unit 32 receives the descrambled data and calculates the payload of the descrambled data in a first stage of an Audio-MPEG sequence of the first digital signal. The combining unit 32 combines the first synchronization signal generated by the unit 34 and the calculated payload to then obtain the preamble of an MPEG Audio structure. The descrambled data is placed after the preamble. In case the bit length of the preamble and that of the descrambled data are not in accordance with the length of an MPEG Audio structure, the pitch must be filled with zeros, so that the correct pitch length is obtained. Then the obtained strings are provided to the output terminal 36 to provide the first digital information signal at the output of the receiver. As described above, the first six PCM samples of a PCM frame contain the first 24 bits of a hidden data pattern, being a synchronization pattern. These 24 bits preferably contain the code: 0xF87E1F (1111 10000111 11100001 1111). It can be noted that the number of bits in a hidden data structure will always be a multiple of eight, the deaeration can be done very efficiently by eight bits. Also the CRC-16 calculation can make use of this fact. In addition, in the described format two bits are reserved in the hidden head. These bits can be used for possible future extensions with a physical channel and / or copy protection mode. According to the invention, only one synchronization pattern is transmitted and the other unique synchronization patterns of the MPEG Audio conditions are regenerated in the receiver. The extraction of the payload of hidden data contained in hidden data structures uniquely decodable from stereo PCM samples 1152 performed by the receiver will now be described in more detail. A hidden data structure is subdivided into three hidden data structures of samples 384 each. Each sub structure of each channel has an individual distribution that is denoted by distrifc] [sub_structure]. For the corresponding channel "c" and subfraudura uSub_structure ° I this distribution indicates the number of LSBs of the PCM sample that is being used to carry the hidden data structure. The header information is always contained in the LSB of the PCM samples. The applied condition is shown in Figure 1. In this example, the distribution of hidden data sub-structures is as given in Table 1.

Table 1: distribution of sub structure. In order to extract the running number of LSBs that are used to sustain the payload of hidden data, first the head needs to be read and interpreted. Depending on the distribution information in the spindle, the remaining LSB of the PCM samples containing the spindle can hold a load of hidden data. For a perceptual control of the spindle information and the hidden data payload, all the LSBs contained in the skeleton_of data, with the exception of the synchronization word, have to pass bit by bit through a deskeletonization module before the interpret on. The de-scrambling unit is illustrated in Figure 4. The following polynomial is applied. Sn = t "T tn-1? th ^? tn_i4? t .e At the end of each stage, all states T i are infcialized to the binary value 1. Figure 4 shows the de-scrambling unit. The T blocks represent change records. Adidons represent "exclusives or portals 0. At the beginning of each structure the change registers are inidalized to the binary value 1. For every new bit Tn, input inserted a new output Sn is generated.

The bits have to be inserted into the descrambler module in a specific order that is explained in figure 5. Figure 5 shows the bits in the structure of hidden_data that need to be inserted into the descrambler module in a specific order. In the figure this is explains through a simplified head and hidden data payload. Assuming that the synchronization word has only 2 bits and the remaining spindle has 6 bits. As illustrated in the figure, the distribution for the first substructure is 3 LSBs for the left channel and 2 bits for the right channel. The synchronization bits labeled "1" and "2" They are read first and do not pass through the randomization module. The remaining bits are read in the order indicated. This order is "first the head" where it is read alternating the left and right channel. After that, (bits are read first MSB.

All bits labeled "3 ..." have to pass through the scrambling circuit before the interpretation. The first action performed in a receiver is the synchronization of decoder for PCM CD-DA samples. The synchronization word is contained in the LSN of the PCM samples representing the left and right channels. ? The distance between two consecutive synchronization words reaches the number of samples PCM 2 * 1152 mono or samples PCM 1152 stereo. In order to recover the synchronization word, a bit stream is generated by concatenating d successively the LSB of the PCM sample corresponding to the left channel and the LSB of the PCM sample corresponding to the right channel. The last 16 bits of this bit stream are compared continuously to the synchronization word. If there is a match for all 16 bits, only then is synchronization achieved.

In another caraderizadón of a receiver, perform two CRC revisions. The error detection methods used are "CRC-4" and "CRC-16" whose polynomial generators are G (X) = X4 + X1 + 1 (CEC-4) G (X) = X16 + X15 + X2 + 1 (CEC-4) The bits included in the CRC_4 revision are the bits after the synchronization_word in the spindle information. The bits included in the revision CRC_16 are the first bits after the synchronization_word in the header information for the position of the reviston_crc16. The CRC method is shown in the CRC review diagram given in Figure 6. For CRC-4, the initial state of the change record is $ F. For CRC-16, the initial status of the change record is $ FFFF.

All the bits included in the CRC revision are entered into the cubicle shown in Figure 6. After each bit is entered, the change record is changed by one bit. After the last change operation, the outputs bn ... bO constitute a word that will be compared with the revision word CRC in the current. If the words are not identical, an error transmission occurred in the field in which the CRC-4. To avoid annoying distortions, the application of a concealment technique is recommended, such as silence (muting) of the structure or the repetition of the previous estrudura. Figure 6 shows a CRC review diagram. Addition blocks represent "exclusives" or portals. The following options for improving the payload in the CD format are available. First, when using only the hidden data channel. No use is made of a physical channel. All header information to extract the payload of hidden data, such as synchronization and distribution information, is merged with the hidden data. The payload represents an MPEG-2 base and an extension structure.

Second, by making use of the hidden data channel and a physical channel. The spindle information is contained in the physical channel. This information is merged with the payload in the physical channel. The payload in the physical channel represents an MPEG-2 base structure. The payload of hidden data represents an MPEG-2 extension. Third, by making use of only one physical channel. The control information is contained in the physical channel. This information is merged with the useful carp in the physical channel. The payload represents an extension structure and MPEG-2 base. In case a physical limited level LML mufti channel is present, it always contains the spindle. Depending on whether a second channel is used, as noted by the content_ descriptor, the LML channel will contain either only the MPEG-2 base station or additionally the MPEG-2 extension channel. If a hidden data channel is used, the start of this command will be synchronized with the payload extracted from the LML channel. - Also in the case where a physical channel is used, either in combination with a hidden data channel or by itself, the MPEG-2 payload structure remains based on PCM 1152 stereo sample structures. PCM 1152 audio corresponds to 192-F3 structures. An F3 structure consists of 24 bytes (user) During formatting of the disk, the inputs of the stereo PCM sample structures 1152 have been aligned with the F3 conditions so that, after the incorporation of the decoding delay of the LML data as a result of error correction, the data of the two channels are of the same structure, this is illustrated in figure 7. Figure 7 shows a structure of stereo PCM samples 1152 corresponding to strings 192 F3. If the synchronization point is detected at the "synchronization point", the data at the "structure start point" becomes available from the physical channel, for this specific condition, the PCM data starts the led at the "synchronization point". At any point of synchronization, at least structures 111 F3 need to be available in the buffer in order to have an adequate amount of physical data available from that point. If this is not the case, decoding can only be initiated at the next synchronization point. The real extradón of the physical payload is independent of the processing • related to the hidden data channel. For each test of samples PCM CD-DA 10 1152, a fixed amount of 290 kbytes of physical payload becomes available. The physical data becomes available byte by byte and the MSB is interpreted first. After the header information is read, the data representing the structure is read (+ extension) MPEG encoded MPEG-2 base * In case the control information is not contained in the hidden data channel, the payload extractor can start in the first PCM sample of the left channel. The synchronization and spindle information are contained in the physical channel. k The "distribution" information describes the number of bits included per subframe of hidden data. An example is given in Figure 8. In addition to the payload data, space is reserved for a CRC-16 operating in the total payload contained in the hidden data channel. In case the hidden data payload is zero, no CRC-16 is written. The payload of hidden data and additionally, if present, the physical payload within a sample structure PCM CD-DA 1152 represents an encoded bit of MPEG2 audio encoded containing multi-channel audio PCM samples 25 1152 In case a physical channel is not used, the hidden data load represents a coded MPEG2 audio stream (base plus extension). In case a physical channel is used, the payload of hidden data represents an MPEG-2 extension current and the physical payload represents the encoded MPEG-2 base rate stream. The number of bits contained in an encoded MPEG2 base station must not exceed the capacity available in the LML channel. The number of bits contained in the encoded MPEG2 extension structure is variable and is a multiple of 8 bits. The division described above is illustrated in Figure 9.

In the case where a physical channel is used, the base mode bits MPEg-2 coded for the corresponding function are extracted and placed in front of the bits_of data_culters. It should be noted that a record carrier with a physical channel is known from USP 5,210,738 and USP 5,724,327 (PHN 13,992) The complete bitstream (base + extension) is decoded and subsequently decoded from MPEG2, resulting in samples of Multi-channel PCM audio 1152. For MPEG2 audio data decoding reference is made to ISO / IEC 13818-3.

While the invention is described with reference to the preferential characteristics thereof, it should be understood that these are not limiting examples. Therefore, several modifications for the experts in the art may become apparent, without departing from the vision of the invention, as defined in the claims. The word 'comprises' does not exclude the presence of other elements or steps apart from those listed in a claim. Any sign of reference does not limit the vision of the claims. The invention can be implemented through hardware and software. Several "media" can be represented by the same hardware article. In addition, the invention lies in each of the novel caraderísticas or combinadón caraderísticas.

Claims (26)

1. CHAPTER CLAIMING Having described the invention, it is considered as a novelty and, therefore, is claimed to contain the following: CLAIMS 1. Transmitter for transmitting a first and second digital information signal via a transmission means, said first digital information signal comprises the first strings having at least a first synchronization signal and a portion of data stored therein, the transmitter comprises: - input means to redirect the first and second digital information signal; - processing means for processing the second digital information signal in subsequent second structures, said second states comprising information blocks of the second digital information signal; - signal combining means for inserting a second synchronization signal and at least the data portion of a first structure in a second phase of the second digital information signal to then obtain a combined state; - output means for providing the combined structures to an output terminal to then obtain a combined signal to be transmitted; characterized in that said signal combining means are adapted to remove the first synchronization signal from said first strings before inserting at least the data portion of the first strings into the second structures.
2. 2. Transmitter as claimed in claim 1, characterized in that the signal combining means is adapted to insert the data portion of a first structure into a second stage of the second digital information signal when using hidden data techniques.
3. 3. Transmitter as claimed in claim 1 or 2, wherein a second structure represents a portion of the second digital information signal of a predefined duration and a first sequence represents a portion of a third digital information signal of substantially the same duration .
4. 4. Transmitter as claimed in claim 3, wherein the first digital information signal is obtained by the data compression of the third digital information signal.
5. 5. Transmitter as claimed in claim 4, characterized in that the first digital information signal is in the form of an MPEG encoded signal. • Transmitter as claimed in claim 4 or 5, wherein the transmitter further comprises means for detecting the available capacity in a second command to insert a first structure and generate a control signal to control the data compression of the transmitter. third digital information signal, said control signal is indicative of the capacity available in said second station. 7. Transmitter as claimed in any of the preceding claims, wherein the second digital information signal comprises at least one PCM signal. 8. Transmitter As claimed in any of the preceding claims, the transmitter is in the form of an apparatus for recording the digital information signal in a record carrier. 9. Transmitter as claimed in any of the preceding claims, wherein the transmitter further comprises channel coding means for coding channels of the transmission signal before transmission. 10. Method for transmitting a first and second digital information signal via a transmission means, said first digital information signal comprises first structures having at least a first synchronization signal and a portion of data stored therein, the method comprises the steps of : receiving the first and second digital information signal; - processing of the second digital information signal in subsequent second structures, said second states comprising blocks of information of the second digital information signal; - insertion of a second synchronization signal and at least the data portion of a first command in a second command of the second digital information signal to then obtain a combined command; - Propounding the combined conditions to an output terminal to then obtain a combined signal to be transmitted; characterized in that the method further comprises the step of removing the first synchronization signal from said first structures before inserting at least the data portion of said first structures in the second conditions. 11. Method as claimed in claim 10, wherein at least the data portion of a first station is inserted into a second station of the second digital information signal using hidden data techniques. 12. Method as claimed in claim 10 or 11, wherein a second structure represents a portion of the second digital information signal of a predefined length and a first term represents a portion of a third digital information signal of substantially the same duration. . 13. Method as claimed in claim 12, wherein the first digital information signal is obtained by the data compression of the third digital information signal. 14. Method as claimed in claim 13, wherein the first digital information signal is in the form of an MPEG encoded signal. 15. Transmission means in the form of a record carrier carrying a combined signal comprising portions of a first and a second digital information signal, said combined signal is a sequence of combined conditions, a combined structure comprises a second synchronization signal and a data portion of a first structure of the first digital information signal, said first structure comprises a first synchronization signal and a data portion, said combined structure is obtained by inserting the second synchronization pattern and at least the data portion of the first digital information signal in a second stage of the second digital information signal, a second stage is obtained by processing the second digital information signal in subsequent second structures, said second stages comprise blocks of information of the second information signal. digital, characterized in q Before inserting at least the data portion of a first structure, at the first synchronization signal 5 said first sequence is removed. 16. Transmission medium as claimed in claim 15, characterized in that at least the data portion of a first structure is inserted into a second structure when using hidden data techniques. 17. Transmission medium as claimed in claim 15 or 16, wherein a second structure represents a portion of the second digital information signal of a predefined duration and a first structure represents a portion of a third digital information signal of substantially the same 15 duradon. ? 18. Transmission medium as claimed in claim 17, wherein the first digital information signal is obtained by compressing data from the third digital information signal. 19. Transmission medium as claimed in claim 15, 16, 17 or 18, wherein the record carrier is of the optical or magnetic engraving type. 20. Receiver for redirecting a combined signal and generating a first and a second digital information signal therefrom, the receiver comprises: receiving means for receiving the combined signal; - first detection means for detecting a second synchronization signal to then obtain a detection signal; - recovery means for recovering a combined state of the combined signal in response to said detection signal; - first means of extracting at least one portion of data from a first stage of the first digital information signal of the combined station; - second extraction means for extracting at least part of the second signal from »Digital information of the combined condition to obtain a second 10 structure of the second digital signal form; - first output means for subsequently propelling the second strings to a second output terminal to then obtain the second digital information signal; in which the receiver also understands; 15 - synchronization signal generator means for generating a first synchronizer signal; - means for combining signals to combine the first synchronization signal and the > minus the data portion of the first digital information signal to then obtain a first signal of the first digital information signal; 20 - second output means for subsequently providing the first strings of the first digital information signal to a first output terminal to then obtain the first digital information signal. 21. Receiver as claimed in claim 20, wherein a second structure represents a portion of the second digital information signal of a predefined length and a first sequence represents a portion of a third digital information signal of substantially the same duration. 22. Receiver as claimed in claim 20 or 21, characterized in that the first digital information signal is a compressed version of data of the third digital information signal. 23. Receiver as claimed in claim 20, 21 or 22, characterized in that »The first digital information signal is in the form of an MPEG encoded signal. 24. Receiver as claimed in claim 20, 21, 22 or 23, wherein the combined signal is a PCM signal and the second digital information signal is substantially the combined signal. 25. Receiver as claimed in any of claims 20 to 24, wherein the receiving device takes the form of a device for reproducing a combined signal recorded in a record carrier. 26. Receiver as claimed in any of claims 20 to 25, wherein the receiver comprises decoding means of channels accommodated immediately after the receiving means.