KR20000016169A - Packetized data formats for digital data storage media - Google Patents

Abstract

PURPOSE: A data format facilitates the association and assembly of the packetized data streams of the program by a decoder, independent of packet identifiers de-mapping data. CONSTITUTION: The storage medium format for a storage medium (105) containing packetized data programs includes packet identifiers (PIDs) that identify individual packetized data streams constituting a program. The PIDs include a base PID for identifying one data stream and a second PID of predetermined offset value to the base PID for identifying a second data stream. Corresponding packetized data streams that constitute different programs are given the same PID (115). The storage medium format may also include program specific information (PSI) suitable for use in recovering data content of a program. The PSI includes an MPEG-like program map table (PMT) and an MPEG-like program association table (PAT) and incorporates a parameter suitable for commanding a decoder (25) to apply the PSI in decoding the program irrespective of previous PSI content. In addition, the PSI may incorporate a version number that is varied between successive occurrences of the PSI irrespective of substantive change in PSI content. One or more private data elements may also be included in the PMT to describe the program.

Description

Packetized data format for digital data storage media

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, and for example to the insertion of storage digital video data information.

In image processing and storage devices, digital image data is typically encoded to meet the requirements of known standard schemes. One such widely adopted standard scheme is the MPEG2 (Movie Expert 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 ". Image data encoded by the MPEG standard scheme usually takes the form of a packetized data stream containing the data contents of many program channels (e.g., channels 1 to 125). For a decoder for decoding this packetized data stream and restoring the image data contents of the program channel selected for display, it is necessary to identify and combine each packet composed of the selected program channel.

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 parts, and is defined to contain enough information to restore the data contents of all program channels constituting the packetized data stream. Moreover, PSI is combined with packetized data streams. This increases the storage capacity needed to store the data stream and reduces the communication bandwidth available for communication of program content. As such, PSI represents additional coding 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 repetitions of the PSI in the packetized data stream. At a minimum, the PSI needs to contain enough information to recover the data contents of all program channels that make up the packetized data stream. The minimum number of repetitions of PSI in a packetized data stream is limited by the desired system operation delay characteristics. For example, the decoder needs an updated PSI to perform the change of program channel controlled by the command 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.

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

The present invention recognizes that it is desirable to store the PSI in a storage medium in a form that minimizes the error use of the PSI of another program for restoring the contents of a program requiring different restoration parameters (arguments). This situation may arise when the storage medium is used to store differently packetized datastreams, such as programs derived from data streams partially overwritten with programs derived from different datastreams. The PSI storage format would ideally reduce program restore latency and minimize irregular access (access) data recovery time. Rapid irregular access is particularly important in the operations of these storage devices, including high speed execution or content skipping (trick play) such as VCRs.

According to the principles of the present invention, the image processing system reduces the processing overhead and the storage overhead imposed by the program designation information (PSI) used for program content restoration. The disclosed system provides a compressed PSI and appropriately inserts this compressed PSI into the packetized datastream to provide reduced processing and storage overhead. The system of the present invention suitably produces PSI by means of various storage media such as, for example, video tapes, digital video discs (DVDs) or CDROMs. In addition, the storage medium format and the packetized datastream format are disclosed to increase data processing efficiency using compressed PSI. The disclosed storage and datastream formats provide reduced program recovery delay time and minimize inaccurate PSI parameters across program boundaries.

A storage medium format for a storage medium that includes a plurality of packetized data programs includes a packet identifier (PID) that identifies each packetized data stream that makes up the program. The data format facilitates the correspondence and combination of packetized data streams of a program by the decoder, regardless of PID de-mapping data. The PID includes a base PID for identifying one data stream and a second PID having a predetermined offset value with respect to the base PID for identifying another data stream. The different programs make up the corresponding packetized data streams provided to the same PID.

Another storage medium format for a storage medium having a packetized data program includes program specific information (PSI) suitable for use in restoring the data contents of the program. The PSI includes a program map table (PMT) for mapping a packet identifier (PID) to each packetized data stream constituting a program. The PSI also includes a program association table (PAT) for associating a program with a PID for identifying a packet having a PMT. The PSI combines the appropriate parameters that control the decoder to apply the PSI to recover the program regardless of the contents of the previous PSI.

In a feature of the invention, a version number is combined in a stored PSI to distinguish between different versions of the PSI, which version number is a continuous occurrence of the PSI regardless of the actual change in the PSI content that occurs continuously. Will change between.

In another aspect of the invention, one or more personal data components may be included in the stored PMT describing the program. This data component is selected from the title, duration, program description, violence rating, viewable age rating, recording time, recording date and version list.

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.

2 is a flow chart illustrating a 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 in a selectable storage medium.

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

4 is a flow diagram illustrating a process of formatting CPSI to ensure that the correct CPSI is used during program decoding.

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

1 shows an image receiving system according to the present invention, for example, to properly generate and insert a compressed PSI into a packetized data stream to be stored. This receiver system generates PSI appropriately for various media types such as, for example, video tape, digital video disc (DVD) or CDROM. In addition, the image receiving system reduces the processing overhead and the storage overhead imposed by the program specification information (PSI) used for program content restoration.

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

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 processed 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 compressed data output for storage and for decryption or communication with other devices. The image receiver user uses the remote control unit 125 to select the program he wants to watch from the on-screen menu selection, the program he wants to save, the type of storage medium and the method of storage. do. Image and audio decoders 85 and 80 decode the compressed data provided from transport system 25 to provide output for display, respectively. Data port 75 provides an interface for transmitting and receiving (communicating) compressed data from transport system 25 to another device, such as a computer or high definition television (HDTV) receiver. Storage device 90 stores compressed data provided from transport system 25 in storage medium 105. In playback mode, the storage device 90 also supports the recovery of compressed data from the storage medium 105 for decoding in the transport system 25, and different storage media (not shown for simplicity). Supports storage or communication with other devices.

In FIG. 1, a carrier wave modulated with image data received by the antenna 10 is converted into a digital form and processed by the input processor 15. In FIG. This 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 a demodulator and decoded by the 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 interfaces 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 compatible packetized transport data stream as defined in MPEG System Standards Section 2.4 and includes 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 contains program specific information (PSI) for use in identifying PIDs and combining each data packet to recover the contents of all program channels that make up the packetized data stream. The image receiver user uses the remote control unit 125 to select the program he wants to watch by the on-screen menu selection, the program he wants to save and the medium to be used for storage. The system controller 115 may use the selection information provided through the interface 120 to configure the system 25 to select a program for storage and display and generate a PSI suitable for the selected storage device and media. . The system controller 115 has the components 45, 47, 50, 55, 65 and 95 of the system 25, which sets the values of the control registers in these components via the data bus and is controlled by the 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 restored from the storage device 90 via the storage interface 95 in the playback mode. In normal non-playback operation, data packets that make up a program selected by the user for viewing are identified by their PIDs by 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 constituting the program selected by the user for storage are identified by their PIDs by 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.

Units 45 and 47 match PIDs of the input packets provided by MUX 37 with PID values pre-loaded by the controller 115 into control registers in units 45 and 47. Adopt detection filter. 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 a picture 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 correspond to each preloaded PID and encryption key. By means of the memory mapped PID and encryption key lookup table, units 45 and 47 can match encrypted packets containing the preloaded PID with a corresponding encryption key that allows their decryption. Unencrypted packets do not have a corresponding encryption key. Units 45 and 47 provide the decryptor 50 with both the identified packets and their corresponding encryption keys. The PID lookup table in unit 45 is also 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 the 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 enabled smart card system 130 from the encryption code extracted from the input datastream. Generation of the encryption key is by naming the customer determined from coded information pre-stored on the insertable smart card itself (1989, International Organization for Standardization ISO document ISO 7816-3 defines the interface and signal structure for smart card systems). ).

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 and unencrypted packets from the unit 45 constituting the program for display are provided to the decoder 55. The decrypted packet provided from the unit 50 and the unencrypted packet provided from the unit 47 having the program for storage 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 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 location 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 unit 45 or 50 at the next empty location in the appropriate destination buffer of unit 60. The read pointer allows sequential reading of packets from the destination buffer of the appropriate unit 60 by the controller 115 and the application interface 70.

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 (relative to 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. In addition, the decoder 55 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 consecutive timing information packets are used by the controller 115 to adjust to the master clock (27 MHz) of the system 25. The difference between the time based on the PCR and the time based on the master clock of the time interval between receipt of successive timing packets generated by the controller 115 is used to adjust the master clock of the system 25. This is accomplished by the controller 115, using the difference in time estimate 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 containing program content with audio, images, captions and other information are stored in packet buffer 60 from decoder 55 by unit 65. It is sent to the selected application buffer. The application control unit 70 sequentially restores audio, images, captions, and other data from the selected 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, for example, a computer program to a computer. Port 75 may also be used, for example, to output data to an HDTV decoder.

The packet containing the PSI information is recognized by the unit 45 which has been selected for the controller 115 buffer in unit 60. PSI packets are sent to the buffer by unit 65 via units 45, 50, 55 in a manner similar to the description for packets containing program content. The controller 115 reads the PSI from the unit 60 and stores it in the internal memory.

The controller 115 generates a compressed PSI (CPSI) from the stored PSI and combines the 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 by the controller 115 in accordance with the PDI of the units 45, 47, the destination and encryption key lookup table and the function of the control unit 65 in the previously described manner.

The CPSI contains information related to the particular program to be stored, while the PSI contains information related to all the 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 fixed, the CPSI may be repeated in the datastream more frequently than the PSI, and may be derived and used to reduce the restoration delay time of the program contents.

PSI, as defined in MPEG system standard section 2.4.4, has four unencrypted components or information tables. These are 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 constituting 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 maps the program number to a PID that allows identification and combination of the packets that make up the PMT. The NIT is an arbitrarily selectable table and can be configured and used to define physical network parameters such as, for example, the satellite transmission channel frequency and the transponder channel. The CAT includes conditional access information, such as an encryption code that controls access to the program according to user naming.

In step 205 of FIG. 2, the controller 115 (FIG. 1) performs procedure initiation by system power up following the initiation in 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). do. In addition, the controller 115 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. In step 205, control unit 65 informs controller 115 whether a PSI packet is present in unit 60 via a PSI interrupt. Upon receipt of the PSI interrupt, the controller 115 repeatedly accesses the packet stored in the buffer of the selected unit 60 to store the complete CAT and PAT data in the internal memory. The controller 115 determines the PID that identifies the PMT and NIT packets from the PAT, and then repeats the process for storing complete PMT and NIT data in the internal memory. Controller 115 continues to access buffer 60 to capture PSI packets in internal memory upon receipt of PSI interrupts while the receiver is powered up. As a result, the controller 115 captures, in its internal memory, the PAT, PMT, NIT and CAT data with the complete PSI of the transport datastream input to the system 25.

In step 210 of FIG. 2, not only the program that the user wants to store, but also the program to be stored in encrypted form, and the user-generated data SP, SM, and SE that identify the medium and the device to be used for the storage are stored in the controller ( 115) (FIG. 1). The user selection data is input to the controller 115 via the interface 120 according to the on-screen menu selection to the remote control unit 125. In step 215, in response to the input selection data SP, the controller 115 derives 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. This allows unit 47 to identify the packets that make up the program selected for storage.

In step 215 of FIG. 2, unit 47 (FIG. 1) provides an unencrypted packet to MUX 110 and encrypts the packet with the corresponding encryption key (identified by the encryption indicator in the packet header data). To the decryption unit 50. The encryption key is provided to the unit 47 by the controller 115 in step 215 of FIG. 2 and then the smart card 130 from the encryption code obtained from the CAT for the selected program SP according to the previously described scheme. Produced by (Fig. 1). 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 packets constituting the program SP to be stored are provided to the MUX 110 in encrypted form or decrypted form according to the selection data SE. In step 225, the controller 115 obtains compressed program specification information (CPSI) for the program SP selected for storage from the complete program specification information (PSI) captured from the transport data stream input to the system 25. Form. The controller 115 forms a CPSI for each program to be stored by adopting the process shown in FIG. 3, at step 225 of FIG. 2.

Following the start of step 300, in step 305 of FIG. 3, the controller 115 re-designates the PID value of the elementary stream constituting the program to be stored and the PID number identifying the PMT and NIT. Except in the case of a perfect match, 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 PID values for picture, voice, caption, PCR, and NIT. Example PID assignments for the two programs to be stored (Program 1 and Program 2) are shown in Table 1.

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 recovery and recovery process performed by the decoder or playback device. The decoder directly identifies the stream and combines the PID demapping data without having to first capture it. However, renumbering PIDs in this manner can potentially cause the PID to be indeterminate, 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 PID numbering in step 305 is adopted in the application device in which the elementary stream group 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.

Other PID assignment schemes may also be used to 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 can 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.

PID Name PID Definition Base + Offset (Hexadecimal) Explanation Program 1 PMT 400 PID for Program Map Table-Base PID burn 401 PID for program picture stream PCR 401 PCR in an image stream Voice 1 406 PID for the first program voice stream Voice 2 407 PID for second program voice stream data 040B PID for program caption stream NIT 040E PID for program network information table Program 2 PMT 400 PID for Program Map Table-Base PID burn 401 PID for program picture stream PCR 401 PCR in an image stream Voice 1 406 PID for the first program voice stream Voice 2 407 PID for second program voice stream data 040B PID for program caption stream NIT 040E PID for program network information table

In step 310 of FIG. 3, the controller 115 generates a program correspondence 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. The PAT may also 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 that the user has selected for storage. 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 includes a PAT, as described later.

In step 315, the controller 115 generates a PMT for each program to be stored using the predetermined numbered PID value to identify the component elementary stream. 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 from 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 recovery 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 smart card insertable in the manner described above.

The encryption system described is exemplary. Another encryption mechanism may be employed including the storage of different encryption codes or keys for decryption. 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 CPSI rather than CAT, so that CAT cannot 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 that the code can be mapped directly to the elementary streams that make up the program, without requiring separate directories for concatenating the elementary streams to the code.

Following step 325 or 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 recorded violence / gender rating, time and date as well as additional optional information on whether the edited version is selectable by the user, as well as the title, duration and description of the program. Have personal data. The stored personal data is combined from the data entered by the user via the remote control unit 125 and the interface 120 and from previously stored PSI information or additionally by the controller 115. The NIT is optional and the user may choose to omit the NIT for any program or all programs to be stored via a menu selection ignoring step 330 of FIG.

In addition, personal data can be merged into the information table of the CPSI rather than the NIT. For example, personal data may be combined in 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 PAT and PMT for each program to form compressed program designation information (CPSI) for each program. The controller 115 additionally combines and combines the optional CAT and NIT data generated for each program into CPSI. Accordingly, the CPSI has a PAT and a PMT, and may include both or one of CAT and NIT. Upon generation of the CPSI, the CPSI includes information associated with the particular program selected for storage from the datastream input to the system 25 and excludes program specific information associated with the program not selected for storage.

However, CPSI can be generated for one or more programs selected for storage from the input transport datastream. 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 retrieval of a plurality of programs selected for storage, as defined in the MPEG standard scheme. If a program is selected for storage from two separate transport datastreams entering the system 25, the CPSI will include a single PAT and two PMTs. One PMT will be stored for each program. CPSI may also 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 result in errors in the identification and combination of data packets in the restoration of program content, for example generating invalid data for display or processing. This problem will 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 seek operations and will 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 start 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. 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 between successive iterations of the CPSI in the program to be stored. The version number counter is incremented continuously through any overflow condition. In accordance with the restoration of the program from the storage medium 105, the decoder or the playback device detects the change in successive version numbers and uses PAT, PMT, CAT and NIT for each generation in the restored program.

Other methods of changing the version number of initializing the decoder may be used to reacquire CPSI. The version number may be increased, for example, between selected CPSI generations within the program of the storage medium 105 or between different programs or between two consecutive first generations of CPSI at the beginning of the program recording. In addition, the version numbers generated at program boundaries between different programs need not be different by any particular number. However, successive version numbers generated within a program must be different for MPEG compatibility. In the case of a device which is not MPEG compatible, the CPSI table version number may be different by any value in the program. Another method that can be employed in step 425 is to specify an individual indicator to be used to command the playback device each time a CPSI is generated or to use CPSI in the selected generation. The assigned indicator will be compatible with MPEG syntax and is located in a section of personal data (section 2.4.3.4 of the MPEG system standard), for example in the adaptation field of a PAT or CAT. This indicator may be arbitrarily defined or may be an existing indicator such as a 'discrete indicator' (defined in section 2.4.3.5 of the MPEG system standard) in the packet header adaptation field, which is a potential discontinuity in CPSI. This 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 context of a datastream that is not compatible with MPEG, additional methods may be used, including, for example, the designation of indicators that are not compatible with MPEG or the use of signals to indicate the start or end of program recording. have. Another technique is to configure the playback device to identify and use each generation of CPSI 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 a disk medium including, for example, a CDROM or a 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 are different between different programs of the storage medium 105 (FIG. 1). In step 430, if the 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 prior to generating and inserting the increased version numbers in the CPSI data, the storage medium via the interface 95 and the device 90. The version number of the program or file recorded in advance from the 105 is restored.

Another method of changing the version number may be used in step 430. However, the CPSI version number must be different among the different programs stored on the medium 105. In addition, individual indicators may be designated in step 430 to provide instructions to the decoder for use of 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 an existing indicator or may be arbitrarily defined, such as a 'discontinuous indicator' in the packet header adaptation field, as described in connection with step 425. In the context of a datastream 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 345 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 the 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 maps 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 the 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 datastream from unit 47 or 50 is also provided to MUX 110. In step 235, the controller 115 uses the CPSI datastream input to the MUX 110 using the path selection signal C to generate a composite datastream output by the MUX 110 to the storage interface 95. Multiplex between program contents. The composite data stream includes a program content packet and a CPSI packet. The controller 115 synchronizes the insertion of the CPSI packet into the program data stream to be stored in accordance with the PSI interrupt signal from the control unit 65 (FIG. 1). The PSI interrupt indicates whether a PSI packet is present 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 create an encrypted or unencrypted program for storage.

In step 235, the controller 115 replaces each generation of PSI data in the data stream to be stored with the corresponding CPSI, regardless of the type of medium selected by the user for storage. However, an additional reduction in coding overhead is achieved 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. The system proposed for high-definition television (HDTV) by ATSC includes, for example, a minimum period of 100 ms between repetitions of the PAT (April 12, 1995, Appendix C of the Digital Television Standard for HDTV Transmission, Section 5.4). Specify the minimum number of iterations for any PSI component. 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.

In 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 buffers from interface 95 using known error encoding techniques such as channel coding, interleaving and Reed Solomon encoding to produce an encoded datastream suitable for storage. A linear storage medium DVHS type device for encoding a data stream. Unit 90 stores the generated encoded datastream that couples the CPSI to tape medium 105.

Other tape storage systems are permitted which perform the writing of two data streams in parallel. The first datastream, which generally includes most of the program content, is typically stored in tape in a spiral. 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 recorded program performs the corresponding CPSI data in parallel with the program contents in the auxiliary track. The number of repetitions of CPSI data in the auxiliary track may be adjusted by limiting the auxiliary track data rate. CPSI can also be stored in a spiral auxiliary track or in a data management area including a track information area (TIA) and can insert and track information sectors (ITI sectors). 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 and input CPSI data to the unit 90, and may combine one or more repetitions.

In addition, the system 25 of FIG. 1 may combine multiple storage / restore paths that support the operation of multiple 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. The program data stream may also be stored in another parallel storage device (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 on-screen menu selection 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. The restoration of the program data stream is started. 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 datastream 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 datastream) 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 datastream for storage via the MUX 110 or for use of the application through the interface 70. Both the playback data stream from unit 95 and the data stream transmitted from selector 35 are processed in a similar manner in system 25, following selection through MUX 37. All of these datastreams are processed in the manner previously described for the transmitted datastream. 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, the system 25 of step 520 transport-decodes the playback datastream to provide decoded data to the application decoders 80, 85 for display. In this mode, the system 25 provides the transport decoded datastream representing the selected program SR for the CPSI data included in the reproduction datastream according to the MPEG standard scheme.

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

Transport data streams in a manner similar to that previously described with respect to FIG. 1 using PID filters 45, 47, decoders 50, decoders 55, buffers 60 and control units 65. Use CPSI for decoding. The transport decoded datastream is provided to the application decoders 80 and 85 for MPEG decoding and image reproduction via the interface 70 except CPSI. In another mode, system 25 provides a playback datastream that couples CPSI to other applications, such as, for example, 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 datastream is stored, for example, in a second storage device other than storage device 90, MUX 110 provides a datastream that couples 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) follow the operation and function of units 90 and 95, respectively.

In the default period, prior to using CPSI, the system 25 displays a picture decoder for displaying a predetermined picture image for display such as, for example, a 'blue screen' or a 'freeze frame'. The decoded data is provided to 85. Similarly, in the default mode, prior to detecting a change in version number and using CPSI, system 25 provides data to speech decoder 80 to blank the speech output. By this method, 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 valid material for viewing. For example, the default period includes a time interval from one of the following states.

(a) detecting the end of the program indicator or supplying power;

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

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

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

The structure of FIG. 1 is not exclusive. 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 (20)

A packet identifier (PID) identifying each packetized data stream constituting the program, the data facilitating correspondence and combination of the packetized data streams of the program by a decoder without regard to PID demapping data. A storage medium in which a plurality of packetized programs are recorded in a format, The PID is, A basic PID identifying one data stream; A second PID having a predetermined offset value with respect to the basic PID and identifying a second data stream, Packetized corresponding data streams constituting different programs are provided to the same PID. The method of claim 1, The basic PID identifies a program map table (PMT) that corresponds to the packetized data stream of the program. The method of claim 2, The PMT combines a personal data element selected from a title, duration, program description, violence rating, viewable age rating, record date, record date and version list into a user defined section. The method of claim 2, And the second PID identifies one data stream from among picture, voice, caption, program clock reference (PCR) or network information table (NIT) data. The method of claim 1, The second PID identifies the network information table (NIT) data, and the NIT stores personal data components selected from title, duration, program description, violence rating, viewable age rating, record date, record date, and version list. And a storage medium. A storage medium in which a packetized data program is recorded in a data format, And program specific information (PSI) suitable for use in restoring the data content of said program, said program comprising: (a) a program map table (PMT) for mapping a packet identifier (PID) to each packetized data stream constituting the program; (b) a program correspondence table (PMT) for associating the program with a PID identifying a packet having the PMT; (c) a parameter suitable for controlling a decoder to use the PSI to decrypt the program, regardless of the contents of previous PSI. The method of claim 6, The parameter is a discrete indicator compatible with MPEG in the packet header. The method of claim 7, wherein And the parameter is set to a logic level for indicating that the PSI is to be processed in a subsequent process of the program. The method of claim 6, The parameter is a transport error indicator compatible with MPEG in the packet header. The method of claim 6, The parameter is a continuous counter compatible with MPEG in the packet header. The method of claim 10, And the continuous counter indicates a mismatch between successive generations of the PSI. The method of claim 11, And the PSI comprises a discrete indicator compatible with MPEG indicating that there is no discontinuity. A storage medium in which a program is recorded in a data format in the form of packetized data, Includes program specific information (PSI) used to restore the data content of the program and recorded in a plurality of locations of the program, the program specific information comprising: A program map table (PMT) for mapping a packet identifier (PID) to each packetized data stream constituting the program; A program correspondence table (PAT) for associating the program with a PID for identifying a packet having the PMT; A version number for distinguishing different versions of the PSI, the version numbers being different between successive generations of the PSI, wherein the version numbers differ regardless of the substantial change in the PSI content between the successive generations. And control the decoder to use the PSI for decryption. The method according to claim 6 or 13, And the PSI is stored at a separate location from the program. The method of claim 14, And wherein said individual location is adjacent to said program. The method of claim 14, And the storage medium is stored on a tape medium and an auxiliary recording track adjacent to a recording track storing the program. The method according to claim 6 or 13, The PMT includes personal data elements describing a program selected from a title, a period, a program description, a violence rating, a viewable age rating, a record date, a record date, and a version list. The method according to claim 6 or 13, The PSI includes a network information table (NIT), wherein the NIT combines personal data components selected from title, duration, program description, violence rating, viewable age rating, record date, record date, and version list. Storage media. A storage medium in which a program is recorded in a data format in the form of packetized data, It is used to restore the data contents of the program, and includes program designation information (PSI) recorded at a location of one of the programs, which program designation information, A program map table (PMT) for mapping a packet identifier (PID) to each packetized data stream constituting the program, The PMT includes one or more personal data elements describing the program selected from a list of titles, periods, program descriptions, violence ratings, viewable age ratings, record releases, record dates, and version lists, And a program correspondence table (PAT) for associating the program with a PID for identifying a packet having the PMT. The method of claim 19, The PSI further comprises a network information table (NIT), wherein the NIT combines the personal data components.