KR100515707B1 - Program specific information formation for digital data processing - Google Patents

Abstract

Program specific information (PSI) is suitably formed for use in restoring the data content of a program in the form of a packetized data stream. Packet identifiers (PIDs) identifying each packetized data stream constituting a program are renumbered, and corresponding packetized data streams constituting a different program are provided to the same PID 115. A program map table (PMT) is created that associates a numbered PID with each packetized data stream constituting the program. In addition, a program association table (PAT) is generated that associates a program with a PID that identifies a packet with a PMT. The parameter may be used in the PSI to indicate that the PSI is used for subsequent processing of the program, regardless of the substantial difference between the PSI and the previous PSI content. In addition, the PSI can combine the changed version numbers between successive occurrences of the PSI regardless of the substantial change in the PSI content. One or more personal data elements may be included in the PMT to describe the program.

Description

Program specific information formation method for digital data processing {PROGRAM SPECIFIC INFORMATION FORMATION FOR DIGITAL DATA PROCESSING}

The present invention relates to the field of digital signal processing. More specifically, the present invention relates to the formation of Program Specific Information (PSI) used for restoring program content, the insertion of storage digital video data information, and the like.

In image processing and storage applications, digital image data is typically encoded to meet the requirements of known standard schemes. One such widely adopted standard scheme is the MPEG2 (Moving Picture Experts Group) image coding standard scheme (hereinafter referred to as the "MPEG standard scheme"). The MPEG standard scheme is the system encoding section (ISO / IEC 13818-1, June 10, 1994) and the image encoding section (ISO / IEC 13818-2, January 20, 1995) (hereinafter referred to as "MPEG system standard scheme" and " MPEG picture standard system ". Picture data encoded by the MPEG standard scheme usually takes the form of a packetized data stream containing the data content of many program channels (e.g., channels 1 to 125). For example, the decoder must identify and combine each packet containing the selected program channel in order to decode this packetized data stream and restore the image data contents of the program channel selected for display.

The MPEG standard scheme defines program specific information (PSI) for use in identifying and combining each data packet to recover the contents of the selected program channel. The PSI includes both user definable and mandatory information elements, and is defined to contain sufficient information for the restoration of the data content of all program channels, including packetized data streams. Moreover, PSI is combined with packetized data streams. This increases the storage capacity required for storing the data stream, while reducing the available communication bandwidth for communication of program content. As such, the PSI represents additional encoding overhead.

The amount of overhead imposed on the PSI depends on the amount of data included in the PSI (size of the PSI) and the number of iterations of the PSI within the packetized data stream. At a minimum, the PSI needs to contain enough information to recover the data content of all program channels including the packetized data stream. The minimum number of iterations of PSI in a packetized data stream is limited by the desired system operating delay characteristics. For example, the decoder needs an updated PSI to perform the change of program channel controlled by the instruction of the television viewer. In conclusion, the minimum number of PSI repetitions is limited by the intention of the television viewer to allow a delay (latency) due to the change of the channel control command. These problems are solved by the system according to the invention.

1 is an illustration of an image receiving system in accordance with the present invention for properly generating and inserting a compressed PSI into a packetized data stream for storage on various types of media.

FIG. 2 is a flow chart illustrating the process of generating compressed program specific information (CPSI) from a PSI and combining the compressed program specific information (CPSI) into a packetized data stream suitable for storage on a selectable storage medium.

3 is a flowchart illustrating a process of forming a CPSI for storing a selected program in a selected storage medium.

4 is a flowchart illustrating a process of formatting CPSI to ensure that correct CPSI is used in program decoding.

5 is a flowchart illustrating a process for restoring a selected program from a selected storage device.

The inventors of the present application recognize that in some applications, it is desirable to reduce the overhead imposed by PSI. For example, in capacity limited digital storage applications, it is desirable to reduce the size of the PSI stored on the storage medium and to reduce the number of PSI repeated on the storage medium. In other image processing applications, it is desirable to reduce the size of the PSI in order to allow more repetitions of the PSI, thereby reducing the restoration waiting time of the program contents. In addition, the generated PSI must meet the operating characteristics and user requirements of the selected storage medium.

In addition, the inventors of the present application recognize that it is desirable to store the PSI in a storage medium in a form that minimizes misuse of the PSI of another program for restoring the contents of a program requiring different restoration parameters (arguments). This situation can occur when the storage medium is used to store programs obtained from different packetized data streams, for example when the storage medium is overwritten with programs obtained from different data streams. In addition, the PSI storage format would ideally reduce program recovery delay time and minimize random access data recovery time. Fast random access is particularly important in the operation of storage devices, including fast playback or content skipping (trick play) such as for example a VCR.

According to the principles of the present invention, the image processing system reduces the processing and storage overhead imposed by the program specific information (PSI) used for program content restoration. The disclosed system provides a compressed PSI and appropriately inserts the compressed PSI into the packetized data stream to provide reduced processing and storage overhead. The system of the present invention suitably generates PSI for various types of storage media such as video tapes, digital video discs (DVD) or CDROMs. Moreover, storage media formats and packetized data stream formats are disclosed that utilize compressed PSI to increase data processing efficiency. The disclosed storage and data stream formats provide reduced program recovery latency and minimize inaccurate PSI parameters across program boundaries.

A method of forming program specific information (PSI) suitable for use in restoring data contents of a program in the form of a packetized data stream is disclosed. The method includes re-specifying a number of a packet identifier (PID) that identifies each packetized data stream constituting the program. The same PIDs are provided for corresponding packetized data streams that make up different programs. A program map table (PMT) is created that associates the renumbered PID with each packetized data stream constituting the program. In addition, a program association table (PAT) is generated. The PAT associates the program with a PID that identifies a packet with a PMT.

As a feature of the invention, a parameter is employed within the PSI that indicates that the PSI will be used for subsequent processing of the program, regardless of the substantial difference between the PSI and previous PSI content.

As another feature of the invention, a version number is incorporated in the PSI to distinguish between differences between different versions of the PSI, which version number varies between successive occurrences of the PSI regardless of the substantial change in the successively generated PSI content. do.

As another feature of the invention, one or more personal data elements may be included in the PMT describing the program. This data element is selected from the title, duration, program description, violence rating, viewable age rating, recording time, recording date and version list.

1 shows an example of an image receiving system according to the present invention which adaptively generates a compressed PSI and inserts it into a packetized data stream to be stored. This receiver system adaptively generates PSI for various media such as video tapes, digital video discs (DVD) or CDROMs. Moreover, the image receiving system reduces the processing and storage overhead imposed by the program specific information (PSI) used for the program content restoration.

Although the disclosed system is described with respect to the contents of an MPEG compatible system for receiving a transport stream encoded in an MPEG manner representing a broadcast program, this is merely exemplary. The principles of the present invention can also be applied to other types of systems, including systems that are not compatible with MPEG, including data streams encoded in other formats. For example, the principles of the present invention can be used in digital video disc (DVD) systems and MPEG program streams. Moreover, although the disclosed system is described for processing broadcast programs, examples are merely illustrative. The term 'program' is used to refer to any form of packetized data, such as telephone messages, computer programs, Internet data or other communication information.

In general, in the image receiving system of FIG. 1, a carrier wave modulated with image data is received at the antenna 10 and processed in the unit 15. The resulting digital output signal is demodulated by demodulator 20 and decoded by decoder 30. The output from the decoder 30 is processed by the transport system 25 in response to a control command from the remote control unit 125. This transport system 25 provides an output of compressed data for use in storage, decryption or communication with other devices. The image receiver user selects the program he wants to watch, the program he wants to save by selecting a menu on the screen using the remote control unit 125, and selects the type of storage medium and the manner of storage. Image and audio decoders 85 and 80 decode the compressed data provided from transport system 25, respectively, to provide output for display. The data port 75 provides an interface for transmitting and receiving (communicating) compressed data from the transport system 25 to another device, such as a computer or a high definition television (HDTV) receiver. Storage device 90 stores compressed data provided from transport system 25 in storage medium 105. Also, in the playback mode, the storage device 90 supports the restoration of compressed data from the storage medium 105 for decoding in the transport system 25, and the storage of different storage media (not shown for simplicity). Or communication with other devices.

Referring to FIG. 1 in detail, a carrier modulated with image data received by the antenna 10 is converted into a digital form and processed by the input processor 15. The input processor 15 includes a radio frequency (RF) tuner, an intermediate frequency (IF) mixer, and an amplifier stage for down-converting the input image signal to a low frequency band suitable for further processing. The resulting digital output signal is demodulated by demodulator 20 and decoded by decoder 30. The output from the decoder 30 is further processed by the transport system 25.

The multiplexer (MUX) 37 of the service detector 33 is either an output from the decoder 30 or an output of the decoder 30 further processed by the National Renewable Standards Committee (NRSS) descrambling unit 40. One is provided via a selector 35. The selector 35 detects the presence of an insertable and NRSS compatible descrambling card, which card is defined in the picture receiver unit (NRSS removable conditional access system is defined in EIA draft document IS-679, project PN-3639). Outputs the unit 40 to the MUX 37 only when currently inserted. In other cases, the selector 35 provides the output provided from the decoder 30 to the MUX 37. The presence of an insertable card allows unit 40 to descramble additional premium program channels, for example, and provide additional program services to the viewer. Note that, in the preferred embodiment, the NRSS unit 40 and the smart card unit 130 (described later for the smart card unit) share the same system 25 interface so that only one of the NRSS card or smart card is available for a predetermined time. Can be inserted in However, the interface may be separated to allow parallel operation.

The data provided from the selector 35 to the MUX 37 is in the form of an MPEG compliant packetized transport data stream, as defined in MPEG System Standards Section 2.4, and contains the data content of one or more program channels. . Each packet containing a particular program channel is identified by a packet identifier (PID). The transport stream includes program specific information (PSI) for use in identifying PIDs and combining each data packet to recover the contents of all program channels including the packetized data stream. The image receiver user selects a program to be watched, a program to be stored, and a storage medium by using the remote control unit 125 to select a menu on the screen. The system controller 115 uses the selection information provided through the interface 120 to select a program for storage and display and to configure the system 25 to generate a PSI suitable for the selected storage device and medium. System controller 115 has components 45, 47, 50, 55, 65, and 95 of system 25, which set control register values in these components via a data bus and are controlled by control signal C. This is accomplished by selecting a signal path through the MUXs 37 and 110.

In response to the control signal C, the MUX 37 selects either the transport stream from the unit 35 or the data stream retrieved from the storage device 90 via the storage interface 95 in the playback mode. In the normal non-playback operation, data packets constituting a program selected by the user for viewing are identified by their PID in the selection unit 45. If the encryption indicator in the header data of the selected program packet indicated that the packet was encrypted, unit 45 will provide these packets to decryption unit 50. In other cases, the unit 45 provides the unencrypted packets to the transport decoder 55. Similarly, data packets containing a program selected by the user for storage are identified by their PID in the selection unit 47. The unit 47 provides the encrypted packet to the decryption unit 50 or the unencrypted packet to the MUX 110 according to the packet header encryption indicator information.

The units 45 and 47 match PIDs of the input packets provided by the MUX 37 with PID values pre-loaded by the controller 115 into the control registers in the units 45 and 47. A detection filter is adopted. The preloaded PID is used in units 47 and 45 to identify the data packet to be stored and the data packet to be decoded for use in providing the image image. The preloaded PID is stored in the lookup table of units 45 and 47. The PID lookup table is memory mapped to an encryption key table in units 45 and 47 that associates each preloaded PID with an encryption key. By means of the memory mapped PID and encryption key lookup table, units 45 and 47 can match encrypted packets containing preloaded PIDs with an associated encryption key that enables their decryption. Unencrypted packets do not have an associated encryption key. Units 45 and 47 provide the decryptor 50 with both the identified packets and their associated encryption keys. In addition, the PID lookup table in unit 45 is memory mapped to a destination table that matches a packet containing a preloaded PID to a corresponding destination buffer location in packet buffer 60. The encryption key and destination buffer location address associated with the program selected by the user for viewing or storage are preloaded into units 45 and 47 together with the PID assigned by controller 115. The encryption key is generated by the ISO 7816-3 compliant smart card system 130 from the encryption code extracted from the input data stream. The generation of the encryption key relies on customer naming determined from coded information pre-stored in the insertable smart card itself (in 1989, the International Organization for Standardization, ISO 7816-3, interfaces and signal structures for smart card systems are defined. has exist).

Packets provided to units 50 by units 45 and 47 are subject to Federal Information Standard (FIP) publications 46, 74 and provided by the Department of Commerce National Technical Information Service. Encrypted according to the Data Encryption Standard (DES) defined in 81. The unit 50 decrypts the encrypted packet using the corresponding encryption key provided by the units 45 and 47 by known techniques. Packets decrypted from the unit 50 containing the program for display and unencrypted packets from the unit 45 are provided to the decoder 55. The decrypted packet provided from the unit 47 containing the storage program and the unencrypted packet provided from the unit 47 are provided to the MUX 110.

Unit 60 includes four packet buffers accessible by controller 115. One of these buffers is allocated to hold data for use in the controller 115, and the remaining three buffers are allocated to hold packets for use in the application devices 75, 80, and 85. Access to packets stored in four buffers in unit 60 by both controller 115 and application interface 70 is controlled by buffer control unit 65. Unit 45 provides a destination flag to unit 65 for each packet identified by unit 45 for decryption. This flag indicates the destination position of each unit 60 for the identified packet and is stored in the internal memory table by the control unit 65. The control unit 65 determines a series of read and write pointers associated with the packets stored in the buffer 60 based on the first-in-first-out (FIFO) principle. The write pointer associated with the destination flag may sequentially store the identified packets from the unit 45 or 50 at the next empty location in the appropriate destination buffer of the unit 60. The read pointer allows sequential reading of packets provided by the controller 115 and the application interface 70 in the destination buffer of the appropriate unit 60.

The unencrypted and decrypted packets provided to decoder 55 by units 45, 50 include transport headers as defined in section 2.4.3.2 of the MPEG system standard. The decoder 55 determines from the transport header whether unencrypted packets and decrypted packets contain an adaptation field (for the MPEG system standard). The adaptation field contains timing information, including, for example, a Program Clock Reference (PCR) that allows synchronization and decoding of content packets. When detecting a timing information packet, that is, a packet including an adaptation field, the decoder 55 sends a signal to the controller 115 that the packet has been received by setting a system interrupt via an interrupt mechanism. The decoder 55 also changes the timing packet destination flag in the unit 65 and provides this packet to the unit 60. By changing the destination flag of unit 65, unit 65 assigns the timing information packet provided by decoder 55 to the unit 60 allocated to hold the data to be used by controller 115, instead of the application buffer location. To the buffer location.

When receiving the system interrupt set by the decoder 55, the controller 115 reads the timing information and the PCR value and stores it in the internal memory. PCR values of successive timing information packets are used by the controller 115 of the system 25 to adjust the master clock (27 MHz). Differences in PCR and master clock sizing based on estimates for the time intervals between successive timing packet receipts generated by controller 115 are used to adjust the master clock of system 25. This is accomplished by the controller 115, using the difference in time estimates derived to adjust the input control voltage of the voltage controlled oscillator used to generate the master clock. The controller 115 resets the system interrupt after storing the timing information in the internal memory.

Packets received by decoder 55 from units 45 and 50, including program content, including audio, pictures, captions, and other information, are designated in packet buffer 60 from decoder 55 by unit 65; Sent to the application device buffer. The application control unit 70 sequentially restores audio, images, captions and other data from the designated buffer in the buffer 60 and provides this data to the corresponding application apparatus 75, 80, 85. FIG. Application devices include voice and picture decoders 80 and 85 and high speed data ports 75. Data port 75 may be used to provide high speed data, such as a computer program, to a computer. Port 75 may also be used to output data, such as to an HDTV decoder.

It is recognized that the packet containing the PSI information is sent by the unit 60 to the controller 115 buffer in the unit 60. PSI packets are sent to the buffer by unit 65 via units 45, 50, 55 in a manner similar to that described for packets containing program content. Controller 115 reads the PSI from unit 60 and stores it in internal memory.

The controller 115 generates a compressed PSI (CPSI) from the stored PSI and combines this CPSI into a packetized data stream suitable for storage in a selectable storage medium. The packet identification and direction processing of FIG. 2 is controlled in the manner described above by the controller 115 together with the functions of the PDI, destination and encryption key lookup table of the units 45 and 47 and the control unit 65.

While the CPSI contains information related to a particular program to be stored, the PSI includes information related to all programs of the data stream to be input to the system 25. In conclusion, CPSI occupies less storage capacity and is given less overhead than PSI. In addition, when the overhead limit is constant, the CPSI may be repeated in the data stream more frequently than the PSI, and thus may be derived and used to reduce the restoration latency of the program contents.

The PSI, defined in MPEG System Standard Section 2.4.4, has four unencrypted components or information tables. These are the Program Association Table (PAT), Program Map Table (PMT), Network Information Table (NIT) and Conditional Access Table (CAT). Each table is formed from data packets recognized by a particular PID. The PMT defines a PDI label that identifies each packetized data stream that makes up the program. Each of these streams is an elementary stream named in the MPEG standard. Basic streams include data streams, such as pictures or audio, for various language and caption data streams. The PAT associates a program number with a PID that allows identification and combination of packets containing a PMT. The NIT is an arbitrarily selectable table and can be configured and used to define physical network parameters such as satellite transmission channel frequency and transponder channel. The CAT includes conditional access information, such as an encryption code that controls access to a program according to user naming.

In step 205 of FIG. 2, the controller 115 (FIG. 1) performs an initialization procedure by system power up following the start of step 200. In step 205, the controller 115 loads the PID values defined in MPEG for the PAT and CAT tables (PID hexadecimal value 0000 and hexadecimal value 0001, respectively) into the PID detection filter of unit 45 (FIG. 1). . The controller 115 also pre-assigns the PAT and CAT packets to the controller buffer of the unit 60 by updating the destination table of the unit 45. PAT and CAT packets detected by the unit 45 are provided to the controller buffer in the unit 60 through the decoder 55 under the control of the unit 65. At step 205, control unit 65 informs controller 115 whether a PSI packet is present in unit 60 via a PSI interrupt. Upon receiving the PSI interrupt, the controller 115 repeatedly accesses the packets stored in the buffer of the designated unit 60 to store the complete CAT and PAT data in the internal memory. The controller 115 determines the PID identifying the PMT and NIT packets from the PAT and then repeats the process for storing complete PMT and NIT data in the internal memory. While powering up the receiver, the controller 115 continues to access the buffer 60 and capture PSI packets in internal memory when receiving a PSI interrupt. As a result, the controller 115 captures, in its internal memory, PAT, PMT, NIT and CAT data with the complete PSI of the transport data stream input to the system 25.

In step 210 of FIG. 2, the data SP, SM, SE generated by the user identifying a program to be stored in encrypted form as well as a program that the user wants to store, a medium and a device to be used for storage are stored in a controller ( 115) (FIG. 1). After selecting a menu on the screen with the remote control unit 125, the data selected by the user is input to the controller 115 via this interface 120. In step 215, in response to the input selection data SP, the controller 115 extracts the programmatic PID selected for storage from the stored PSI. The unit 47 detection filter is loaded with the PID of the program to be stored by the controller 115. As such, unit 47 may identify the packet that contains the selected program for storage.

In step 215 of FIG. 2, unit 47 (FIG. 1) provides the unencrypted packet to MUX 110 and identifies the encrypted packet (identified by the encryption indicator in the packet header data) with an associated encryption key. To the decryption unit 50. The encryption key is generated by the smart card 130 (FIG. 1) from an encryption code obtained from the CAT for the selected program SP according to the manner previously described, and then sent to the controller 115 in step 215 of FIG. By the unit 47. However, if the selection data SE requires encrypted storage, unit 47 sends an encrypted packet to MUX 110 to be stored. In conclusion, in step 215 of FIG. 2, the packet including the program SP to be stored is provided to the MUX 110 in encrypted form or decrypted form according to the selection data SE. In step 225, the controller 115 obtains the compressed program specific information CPSI for the program SP selected for storage from the complete program specific information PSI captured from the transport data stream input to the system 25. Form. The controller 115 forms the CPSI for each program to be stored in step 225 of FIG. 2 by employing the process shown in FIG.

Following the start of step 300, in step 305 of FIG. 3, the controller 115 renumbers the PIDs of the elementary streams that make up the program to be stored as well as the PIDs identifying the PMTs and NITs. Except in the case of a coincidence, the renumbered PID value is different from the corresponding PID value recovered in the PSI of the transport stream input to the system 25. The numbered PID is determined by assigning a fixed (base) PID to identify the PMT and adding a predetermined offset value to the base PID to determine the PID values for the picture, voice, caption, PCR, and NIT. An exemplary PID allocation method is shown in Table 1 for two programs (Program 1 and Program 2) to be stored.

As can be seen from Table 1, the corresponding elementary streams for the two programs are provided in the same PID, for example the picture streams for programs 1 and 2 are both identified by PID = 0401. Assigning the same PID value to the corresponding elementary stream simplifies the data retrieval and recovery process performed by the decoder or playback device. The decoder can directly identify the stream without having to first capture and combine the PID demapping data. However, renumbering PIDs in this manner can potentially cause the PID to be uncertain, and the numbered elementary streams belonging to each program may not be combined. Otherwise, elementary streams that share the same PID and belong to different programs can result in a faulty program assembly. In conclusion, the reassignment of PID numbers in step 305 is adopted in an application device in which elementary stream groups belonging to each program can be individually identified. Such applications include data stream generation and tape storage where the elementary streams of each program are not combined with each other.

Alternatively, other PID assignment schemes may be used that avoid potential PID uncertainties. For example, the default PID value is based on the high-definition television (HDTV) signal decoding of section 8.4.7.1 of "Digital Television Standard for HDTV Transmission" of April 2, 1995, proposed by the Advanced Television Systems Committee (ATSC) of the United States. As suggested for this purpose, in particular, it may be assigned to identify individual programs. In addition, the PID value of the elementary stream constituting the program may be transferred and stored without being renumbered. This configuration can be performed simply, but does not simplify the data recovery process. Note that the PIDs identifying PAT and CAT are 0000 and 0001 (hexadecimal), respectively, as defined in the MPEG standard.

In step 310 of FIG. 3, the controller 115 generates a program association table PAT having a PID value (hexadecimal) equal to 0000. The PAT is preferably generated only for each program currently stored, and a new PAT is created for each stored program. Thus, the PAT contains only the entries necessary for the identification of a single program map table (PMT). In the example program shown in Table 1, the CPSI of both Program 1 and Program 2 will include a PAT with a PID entry 0400 identifying a single PMT. In addition, the PAT may be configured to include an entry for identification of a PMT for every program that the user has selected to store or for all programs previously stored on the storage medium in addition to the user's choice to store. To generate the latter type of PAT, the controller 115 restores the PID of the pre-recorded PMT from the storage medium 105 via the interface 95 and the device 90 prior to generating the PAT. Once the NIT is generated, the PID that allows identification of the NIT packet, as described later, includes the PAT.

In step 315, the controller 115 generates a PMT for each program to be stored using the predetermined numbered PID value to identify the elementary stream of components. The elementary stream constituting each stored program is determined by the controller 115 from previously stored PSI data. In step 320, the controller 115 determines from the user input data SE provided via the interface unit 120 (FIG. 1) whether each program has been stored in encrypted form. If the program is stored in unencrypted form, the controller 115 continues execution of step 330 of FIG. 3 and does not generate a conditional access table CAT. If the SE data requires encrypted storage of the program, the controller 115 generates a CAT for the program that combines the encryption code, at step 325. The stored encryption code is restored in a subsequent program retrieval operation and is used to generate an encryption key that allows, for example, decryption of the encrypted program for display. This encryption key can be generated from the recovered code if allowed by the naming data previously stored on the insertable smart card in the manner described above.

The described encryption system is merely exemplary. Alternative encryption mechanisms may be employed including storage of different encryption codes and decryption keys. Other naming mechanisms that do not include code storage do not necessarily require CAT. In addition, the encryption code is combined in the information table of the CPSI rather than the CAT, so that the CAT may not be used. For example, the encryption code can be combined in the CA_descriptor personal data section of the PMT (by MPEG System Standardization Section 2.6.16). This method has the advantage of directly associating the code with the elementary streams that make up the program, without requiring separate directories to link the elementary streams to the code.

Following step 325 or step 320, the controller 115 generates a network information table (NIT) for each program to be stored, in step 330. The NIT generated by the controller 115 may include, for example, the title, duration and description of the program as well as additional optional information regarding whether the edited version is selectable by the user, as well as the recorded violence / gender rating and time and date. Personal data may be provided. The stored personal data is combined by the controller 115 from previously stored PSI information, or additionally from the data entered by the user via the interface 120 with the remote control unit 125. The NIT is an option, and the user may choose to omit the NIT for any program or all programs to be stored through a menu selection ignoring step 330 of FIG.

In addition, personal data may be aggregated into information tables of CPSI rather than NIT. For example, personal data may be coupled to the user personal descriptor portion of the PMT (by MPEG System Standardization Section 2.6). This method has the advantage that the personal data can be directly mapped to the elementary stream constituting the program, without requiring a separate directory for linking elementary streams to the personal data.

In step 335, the controller 115 combines the PAT and PMT generated for each program to form compressed program specific information (CPSI) for each program. The controller 115 additionally combines and combines optional CAT and NIT data generated for each program to CPSI. Thus, the CPSI has a PAT and a PMT, and may include both or both of CAT and NIT. Upon generation of the CPSI, the CPSI includes information related to the particular program selected for storage from the data stream input to the system 25 and excludes program specific information related to the program not selected for storage.

Alternatively, however, CPSI may be generated for one or more programs selected for storage from the input transport data stream. In this case CPSI will include a single PAT and PMT, and may include a single CAT and a single NIT. In this case, these tables contain data that supports the identification and restoration of a plurality of programs selected for storage, as defined in the MPEG standard scheme. For example, if a program is selected for storage from two separate transport data streams entering the system 25, the CPSI will include a single PAT and two PMTs. One PMT will be stored for each program. In addition, the CPSI may include a single CAT and two NITs. One NIT will be stored for each program.

In restoring a program from a storage medium, a problem occurs when a playback device incorrectly uses CPSI of different programs. The use of incorrect CPSI data, such as PMT, will lead to errors in the identification and combination of data packets in the restoration of program content, for example to produce invalid data for display or processing. This problem may arise, for example, if the playback device does not use the CPSI of the restored program or if the CPSI has changed and continues to use previously derived CPSI for different programs. Similar problems will arise if the storage medium contains more than one program. In this case, the playback device will, for example, violate program boundaries during playback or search operations and continue to use the CPSI of the previous program. To mitigate the problem of using incorrect CPSI parameters that violate program boundaries, the controller 115 adopts the process of FIG. 4 at step 340 to format the CPSI.

In step 405 of FIG. 4, following the commencement of step 400, the controller 115 determines the type of storage device and media selected by the user from input data SM provided through interface 120. For example, if the selected medium is a linear type, that is, a sequential access medium such as a video tape used for digital VHS (DVHS), the controller 115 performs step 410 followed by step 425. In step 425, the controller 115 changes the version number associated with the PAT, PMT, CAT and NIT according to the MPEG syntax (MPEG System Standards Sections 2.4.4.-2.4.4.11). This version number is changed by continuously increasing the version number while the CPSI is continuously repeated in the program to be stored. The version number counter is incremented continuously through any overflow condition. In the case of retrieving a program from the storage medium 105, the decoder or playback apparatus detects the continuous change of the version number and uses PAT, PMT, CAT and NIT whenever a change occurs in the retrieved program.

Other methods of changing the version number may be used to initialize the decoder to reacquire CPSI. The version number may, for example, be increased in the program of the storage medium 105 or between the first two CPSIs generated at the beginning of the program recording, or between occurrences of the selected CPSI within the program. Moreover, the version numbers generated at program boundaries between different programs need not be different by any particular number. However, consecutive version numbers generated within the program must be different one by one in order to comply with MPEG. In the case of MPEG non-compliant applications, the CPSI table version number may be different by any value in the program. Another method that may be employed in step 425 is to specify an individual indicator to be used to command the playback device to use CPSI each time CPSI is generated or in the selected generation. The assigned indicator will be compatible with MPEG syntax, for example located in the Personal Data section (section 2.4.3.4 of the MPEG System Standard) in the adaptation field of the PAT or CAT. This indicator may be arbitrarily defined, or may be an existing indicator such as 'discontinuity indicator' (defined in section 2.4.3.5 of the MPEG system standard) in the packet header adaptation field. Is set to '1' to indicate a decoder or playback device to be used for the next generation of PAT, PMT, CAT and NIT information. The use of such discrete indicators is not considered in the MPEG standard scheme.

In the case of a data stream that is not compatible with MPEG, additional methods may be used, including, for example, the use of signals to indicate the start or end of a program recording or the specification of an indicator that is not compatible with MPEG. Another technique is to configure the playback device to identify and use the CPSI whenever it is generated in the recovered data stream, regardless of the version number. In this case step 425 is ignored.

If the selected storage medium 105 is a non-linear type, i.e., a medium that performs non-sequential access, such as, for example, a disk medium including a CDROM or DVD, the controller 115 performs step 415 followed by step 430. For non-linear types of media, CPSI data may be stored in program content such as one or more specific directory locations on the media or media of linear type. In step 430, if the CPSI is stored in a directory location, the controller 115 changes the version number associated with the PAT, PMT, CAT and NIT at the directory location. The version number is increased to match the MPEG syntax to ensure that the version numbers will be different between different programs of the storage medium 105 (FIG. 1). In step 430, if CPSI is stored in the program content, the controller 115 changes the version number as described in step 425 for the linear type of medium. In order to ensure that the version numbers of the CPSI components are different between different programs, the controller 115 may, via interface 95 and device 90, prior to generating and inserting the increased version numbers in the CPSI data. The version number of the program or file recorded in advance from the storage medium 105 is restored.

Another method of changing the version number at step 430 may be used. However, the CPSI version number must be different among the different programs stored on the medium 105. Alternatively, individual indicators may be designated in step 430 to provide instructions to the decoder to use CPSI when violating program boundaries or initiating a program. The assigned indicator will be compatible with the MPEG syntax and is located in the private data section, for example the adaptation field of the PAT or CAT (section 2.4.3.4 of the MPEG system standard). The indicator may be defined randomly or may be an existing indicator such as a 'discontinuous indicator' in the packet header adaptation field as described in connection with step 425. In the case of a data stream that is not compatible with MPEG, the indicator may specify a command to cause the decoder or playback device to use CPSI. This indicator may, for example, indicate the start and end of a program record.

If the selected storage medium 105 is a solid state, ie, a semiconductor memory such as a RAM, the controller 115 performs step 420 followed by step 430. When using a solid state type storage medium as a non-linear medium, CPSI data is typically stored in one or more specific directory locations on the medium and is easily accessible from other storage locations. In conclusion, the controller 115 mitigates the problem of using incorrect CPSI parameters that violate program boundaries by formatting CPSI for a solid state storage medium, such as a nonlinear type of storage medium. That is, the controller 115 uses the process of step 430.

The process of FIG. 4 ends at step 435 following step 425 or 430, resulting in the CPSI formatting of step 340 of FIG. The process of FIG. 3 ends at step 340 following step 340, where the formation of CPSI for the program selected for storage including step 225 of FIG. 2 is completed. The controller 115 continues the process of step 2 with execution of step 230.

In step 230, the controller 115 forms CPSI data in a section according to the MPEG syntax (paragraph 2.4.4.3-2.4.4.11 of the MPEG system standard). Sections are formed for PAT data and PMT data. In addition, when these tables are coupled to CPSI in the process of FIG. 3 described previously, sections are formed for optional CAT and NIT (personal data). The packetized data as a result of this includes a table identifier, a section length identifier, and a version number previously determined in the process of FIG. Note that the PAT section contains a transport stream identifier that associates the PAT to a particular transport stream. The controller 115 obtains this identifier from the original PSI data and inserts it into the transport stream identifier field of the PAT section of CPSI. However, it will be optional for this field to remain unchanged or left blank.

In step 230, the controller 115 adds the header data to the CPSI data section to format and packetize the CPSI data for insertion into a data stream to be stored. The controller 115 generates headers according to sections 2.4.3.2 and 2.4.3.3 of the MPEG system standard scheme from PSI header data stored in its internal memory. However, CPSI section data is different in length from corresponding PSI section data. Thus, a new header parameter including a 'discontinuous count' indicator and a 'payload unit initiation indicator' is generated by the controller 115 and inserted into each indicator field in the header data. The new discrete count indicator generated by the controller 115 reflects the packet number of the PID for the CPSI component, for example, instead of a different packet number for the PID of the corresponding PSI component. The new payload unit initiation indicator generated by the controller 115 identifies the first byte of the CPSI section, eg, instead of the first byte of the corresponding PSI section.

In step 235 of FIG. 2, CPSI in the form of section data compatible with the packetized MPEG formed in step 230 is provided to the MUX 110 (FIG. 1) by the controller 115. As previously described in connection with step 215, the program content packet data stream from unit 47 or 50 is also provided to MUX 110. In step 235, the controller 115 uses the path selection signal C to program the CPSI data stream and program to generate the composite data stream output by the MUX 110 to the storage interface 95. Multiplex between content. The composite data stream includes a program content packet and a CPSI packet. The controller 115 synchronizes the insertion of the CPSI packet with the program data stream to be stored in accordance with the PSI interrupt signal generated by the control unit 65 (FIG. 1). The PSI interrupt indicates that there is a PSI packet in the buffer 60, as described in connection with step 205. In this manner, the packetized PAT, PMT, CAT and NIT of the CPSI are inserted into the PSI location to replace the corresponding section of the PSI. Unencrypted CPSI data may insert an encrypted or unencrypted program content datastream input to MUX 110 to generate an encrypted or unencrypted program for storage.

In step 235, the controller 115 replaces each PSI data generated in the data stream to be stored with a corresponding CPSI, regardless of the type of medium selected by the user for storage. However, the encoding overhead can be further reduced by inserting the CPSI only once in the program to be stored or by inserting the CPSI at the selected PSI location. The number of repetitions of the CPSI in the program to be stored may be determined by the controller 115 based on factors including, for example, a minimum PSI component repetition number limit, a user preference, a data storage capacity limit, or a selected storage medium type. Systems proposed for high-definition television (HDTV) by the ATSC include, for example, a minimum period of 100 ms between iterations of the PAT (April 12, 1995, Appendix C of the Digital Television Standard for HDTV Transmission, Section 5.4). Specify the minimum number of repetitions for the PSI component of. In addition, for example, in a non-linear or solid state type storage medium, reducing the number of repetitions of CPSI or inserting CPSI only in a program to be stored does not adversely affect the program recovery delay time. This is because these types of media allow for high speed out of order (irregular) data access.

At step 240, storage interface 95 receives a program to be stored from MUX 110 in the form of a packetized data stream (hereinafter referred to as CPSI stream) combining CPSI. The process of FIG. 2 used in the controller 115 to generate the CPSI stream ends at step 245. Note that the CPSI stream may be provided for other applications in step 240, such as display or communication over interface 70, instead of storage over interface 95.

The CPSI stream from MUX 110 is buffered by interface 95 to reduce gaps and bit rate variations in data. As a result, the buffered data is processed by the storage device 90 and properly stored in the medium 105. The controller 115 provides the storage device 90 by providing control commands through the I / O port 100 using a standardized CEBus control protocol (December 1989, Home Automation Standard (CEBus), EIA / IS-60). The operation of Fig. 1 is started and controlled. Storage device 90 uses known error encoding techniques such as channel coding, interleaving and Reed Solomon encoding to generate an encoded data stream suitable for storage from interface 95. A linear storage medium DVHS type device that encodes a buffered data stream. Unit 90 stores the resultant encoded data stream that combines CPSI on tape medium 105.

Other tape storage systems are permitted which perform the writing of two data streams in parallel. The first data stream, which generally includes most of the program content, is stored on a conventional helical tape. Second data streams with lower data densities and bit rates are stored in parallel (non-spiral) form on an auxiliary track located towards the edge of the tape. In this type of storage system, the device 90 preferably separates the CPSI data from the CPSI stream and stores the CPSI data in an auxiliary track. The unit 90 stores the CPSI data in such a manner that each program recorded on the tape transmits the related data to an auxiliary track in parallel with the program. The number of repetitions of CPSI data in the auxiliary track may be adjusted by limiting the auxiliary track data rate. In addition, CPSI can be stored in a spiral auxiliary track or in a data management area including a track information area (TIA) and can insert and track an information sector (ITI sector). The data management area can be stored in a spiral or non-helical manner in parallel with the program content.

Although the DVHS device is described as storing data in a linear type storage medium in the exemplary embodiment of FIG. 1, the storage unit 90 may be any type of storage unit. For example, unit 90 may be a solid state or non-linear type of device for storing data in RAM, DVD or CDROM. If unit 90 and medium 105 are a non-linear or solid state type storage system, unit 90 separates CPSI data from the CPSI stream and stores CPSI data in a predetermined directory section of the medium. This has the advantage of avoiding repeated storage of CPSI and reducing the required storage capacity. In addition, the unit 90 may store the CPSI stream formed and input in the unit 90 to integrate one or more repetitions of CPSI data.

Moreover, the system 25 of FIG. 1 may include a plurality of storage / restore paths that support operation of a plurality of types of storage devices, including linear, non-linear, and solid state types. The single storage / restore path shown in FIG. 1 has a plurality of units 47, 90, 95, 105 and 110, as described. By copying these components to create a parallel storage function, the system 25 is easily extended to combine multiple storage paths. The storage path and program for the particular storage device utilizes the remote control unit 125, as previously described via the interface 120 by user-generated data SP and SM input to the controller 115. Is selected according to the on-screen menu selection.

The system 25 of FIG. 1 restores the program from the storage device 90 and the medium 105 in the playback mode using the process of FIG. The recovered data stream is processed by the system 25 and provided to the application devices 75, 80, 85, for example for display or output. Also, program data streams may be stored in other parallel storage devices (not shown in FIG. 1 for simplicity).

In step 505 of FIG. 5 following the commencement of step 500, the user-generated data SR, SM are input to the controller 115 of the system 35 of FIG. 1 identifying the program to be restored and the program from the storage device. Is restored. User selection data is input to the controller 115 via the interface 120 by menu selection on the screen using the remote control unit 125. The program selected by the user is restored from the storage device 90 of FIG. 1 by way of example. In step 510, the controller 115 is selected by the device 90 from the medium 105 by providing control commands through the I / O port 100 using a standardized CEBus control protocol, as previously described. Start the restoration of the program data stream. The storage device 90 encodes the error coded data recovered from the medium 105 in order to restore the corresponding data originally provided to it for storage. Storage device 90 may be a DVHS linear type storage unit or another type of storage unit such as a solid state RAM, a nonlinear type DVD or CDROM type device. The recovered decoded data stream is transmitted by the storage device 90 to the interface 95 in step 510. This data transmission is controlled and synchronized by the controller 115 via the standardized CEBus. The interface 95 temporarily stores the data received from the unit 90 to adjust the time interval between the data packets, thereby providing a buffered data output compatible with MPEG and subject to the MPEG bit rate limitation.

In step 515, the controller 115 provides the buffered output (replay data stream) from the interface 95 to the PID selection units 45, 47 via the MUX 37 using the path selection signal C. In step 520, the units 45, 47 and the remaining units of the system 25 process the playback data stream for storage via the MUX 110 or for use of the application through the interface 70. Both the reproduction data stream from the unit 95 and the data stream transmitted from the selector 35 are processed in a similar manner in the system 25, following selection through the MUX 37. All of these data streams are processed in the manner previously described for the transmitted data stream. However, the playback data stream selected via MUX 37 is already combined with CPSI. Thus, in the playback mode, the controller 115 at step 520 does not perform the steps for the CPSI information described in connection with FIGS.

In the exemplary playback mode shown in FIG. 5, system 25 of step 520 transport-decodes the playback data stream to provide decoded data to application decoders 80 and 85 for display. In this mode, the system 25 provides a transport decoded data stream indicating the selected program SR for CPSI data included in the reproduction data stream, according to the MPEG standard scheme.

In step 520, the controller 115 accesses the playback data stream CPSI data through the buffer 60 and examines the data to see if a change in version number occurs between successive CPSI components. The controller 115 also examines the playback data stream to see if there is a discontinuity indicated by the 'discontinuity indicator' in the packet header adaptation field (defined in section 2.4.3.5 of the MPEG system standard scheme). When detecting a change or discontinuity of the version number, the controller 115 transport-decodes the reproduced data stream using the finally completed CPSI data. Note that the controller 115 may be programmed to use the finally completed CPSI data in accordance with various other conditions, such as discrepancy in discrepancy between consecutive packets of a particular PID and detection of transmission error indications. All of these parameters are present in the playback data stream packet header (defined in section 2.4.3.2 of the MPEG system standard scheme). In addition, the controller 115 is an MPEG standard scheme. Or may be programmed to use CPSI to detect discontinuities between a display time stamp (PTS) or a decoding time stamp (DTS) defined in another user defined time stamp. However, it should be noted that the syntax compatible with MPEG should be set to indicate the occurrence of the discrete count mismatch.

Transport decoding of the playback data stream in a manner similar to that described above in connection with FIG. 1 using PID filters 45, 47, decoder 50, decoder 55, buffer 60 and control unit 65 CPSI is used for this. The transport decoded data stream is provided to the application decoders 80 and 85 for MPEG decoding and image reproduction via the interface 70 except CPSI. In another mode, the system 25 provides a playback data stream that incorporates CPSI to other applications, such as high speed data port 75. CPSI can then be used to transport-decode the playback data stream by these applications or accompanying devices as needed. If the playback data stream is stored, for example, in a second storage device other than the storage device 90, the MUX 110 provides a data stream that couples the CPSI to the second storage device via the second storage interface. In addition, the second storage device and the interface (both not shown in FIG. 1) mimic the operation and function of units 90 and 95, respectively.

In the default period, prior to using the CPSI, the system 25 may be connected to a picture decoder 85 that displays a picture image for some display, such as a 'blue screen' or a 'freeze frame'. Provide the decrypted data. Similarly, in the default period, prior to detecting a change in version number and using CPSI, system 25 provides data to speech decoder 80 to blank the speech output. In this way, it is possible to prevent the image or audio output from adversely affecting the playback device until the correct CPSI data is used to provide the material valid for viewing or listening. For example, the default period includes a time interval from one of the following states.

(a) End of program indicator or detection of power supply

(b) detecting user commands including fast playback or content skipping (trick play), or

(c) Detection of an error condition indicating that no valid picture packet was detected until a change in the CPSI component version number was detected.

Data from the interface 70 decoded by the application decoders 80 and 85 are provided to the units 80 and 85 through the audio and image reproducing apparatus, respectively. This completes the playback process ending at step 530. Note that the controller 115 may employ any other method previously discussed to prevent incorrect CPSI data usage.

The structure of FIG. 1 is not unique. Other structures may also be derived in accordance with the principles of the present invention to achieve the same object. In addition, the functionality of the components shown in FIG. 1 and the processing steps of FIGS. 2-5 may be achieved in whole or in part within the programmed instructions of the microprocessor. Moreover, the principles of the present invention can be applied to any form of electronic program guide that is not compatible with MPEG, and these principles can be carried out without limitation in PSI tables compatible with MPEG.

Claims (14)

A method of forming program specific information (PSI) suitable for use in storing and restoring data contents of a program in the form of a packetized data stream in a video decoder system, the method comprising: The predetermined PID is assigned by assigning a predetermined PID to the packetized data stream constituting the program and renumbering a packet identifier (PID) identifying each packetized data stream constituting the program. Renumbering the PID number so that the packetized data stream can be identified without first acquiring program map information associated with the packetized data stream; Generating program map information for associating the renumbered PID with each packetized data stream constituting the program; Generating program association information that associates the program with a PID that identifies a packet that includes the program map information. The method of claim 1, wherein the same PID is assigned to corresponding packetized data streams that make up a different program. The program of claim 1, further comprising creating personal data elements describing the program, selected from a title, duration, program description, violence rating, viewing age rating, recording time, recording date, and version list. How to Form Specific Information. A method of forming program specific information (PSI) suitable for use in restoring data contents of a program in the form of a packetized data stream, the method comprising: (a) associate a packet identifier (PID) with each packetized data stream constituting the program, (b) associate an individual program with one or more personal data elements describing the program, selected from a title, duration, program description, violence rating, viewership age rating, recording time, recording date, and version list. Generating program map information, the program map information being capable of obtaining individual data elements of an individual program without obtaining additional PSI data; Generating program association information that associates the program with a PID that identifies packets containing the program map information. The method of claim 4, wherein Generating network information, And including the one or more personal data elements in the network information. 5. The method of claim 4, further comprising collating the personal data elements with respect to an individual program. 4. The method of claim 3, further comprising including the personal data elements in a user defined section of the program map information. 4. The method of claim 3, further comprising generating network information and including the personal data elements in the network information. The method of claim 1, further comprising including an encryption code in the program map information. 2. The method of claim 1, further comprising generating conditional access information and including an encryption code in the conditional access information. A method of forming program specific information (PSI) suitable for use in restoring data contents of a program in the form of a packetized data stream, the method comprising: Generating program map information associating a packet identifier (PID) with each packetized data stream constituting the program; Generating program association information for associating the program with a PID that identifies packets containing the program map information; Including a command parameter in the current PSI to instruct a decoder to use the current PSI regardless of the substantial difference between the current PSI and previous PSI contents when processing the program. . The method of claim 11, The command parameter is suitable for instructing a decoder to use the current PSI when restoring the program from a storage medium. 12. The method of claim 11, wherein including the command parameter comprises including a PSI version number, wherein the PSI version number is independent of the actual PSI content of the current PSI and the previous PSI content. A method of forming program specific information that varies between PSI contents. 12. The method of claim 11, further comprising creating personal data elements describing the program, selected from title, duration, program description, violence rating, viewable age rating, recording time, recording date, and version list. Program-specific information forming method.