JP2011003962A - Video voice decoder and video voice decoding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video voice decoder at least continuing the supply of continuous viewing of video to a user, even when restarting occurs at software processing for signal decoding processing.SOLUTION: When a system monitoring portion 10 in the video voice decoder detects abnormalities, it records a history of the abnormalities in a memory 11. The system monitoring portion 10 then notifies a system controller 6 of information on the detected abnormalities. The system controller 6 performs abnormality level determination processing for each of a plurality of regular tasks, and executes and controls abnormality return processing corresponding to the determined abnormality level, based on the abnormality information acquired from the system monitoring portion 10. One of the abnormality return processing is the necessary minimum abnormality return processing where a degeneration task is initiated to perform descrambling processing and video voice decoding processing. The degeneration task operates only during restarting of an abnormality task determined as a regular task requiring restarting.

Description

  The present invention relates to a video / audio decoding device such as a digital broadcast receiving device, and in particular, when an abnormal operation state occurs and a system reboot is required, the video / audio output being viewed can be continued even during the system reboot, enabling continuous viewing. The present invention relates to a video / audio decoding device and a video / audio decoding method.

  Conventionally, in digital broadcasting, the content of one or a plurality of broadcast programs is compressed and encoded by an MPEG2 encoder, and the video and audio of the broadcast program are numbered by arbitrary identification information called PID (Process IDentification), Each PID is packetized into a one-packet 188-byte structure called a transport packet (TP) and sent out in a time-sharing manner. This set of TPs is called a transport stream (TS).

  In recent years, terrestrial digital broadcasting services have been started. In terrestrial digital broadcasting, a copy control signal is added to a broadcast wave for the purpose of copyright protection, and TS is encrypted and transmitted. In order to receive and view digital terrestrial broadcasts, a “key” for releasing scramble is used. The key is in an IC card (B-CAS card) in which key data is recorded.

  In order to view a desired broadcast program, it is necessary to decrypt the cipher according to a descrambler decryption key using an IC card, a CBC (Cipher Block Chaining) initial value, and a card ID described in the standard ARIB STD-B25 .

  The transport packet (TP) in which one or a plurality of broadcast programs are multiplexed indicates the relevance of the video and audio transport packets to be viewed and the PID that is the video and audio identification information constituting the broadcast program. A transport packet (TP) of program specification information called PSI (Program Specific Information) containing information is extracted.

  Select a program from PSI / SI (Service Information), select the corresponding TS, refer to the scramble flag or refer to the ECM (Entitlement Control Message) by IC card, free program without scramble, free with scramble Watch programs and pay-per-view (PPV) contracted pay programs.

  In digital broadcasting, information indicating a service ID terrestrial broadcast program allocated for each service is called a PAT (Program Association Table), and information indicating the relevance of PID which is video or audio identification information for each broadcast program is PMT (Program Map Table).

  The PAT stores all currently transmitted broadcast programs. One broadcast program is identified by a number called Program Number, and has a one-to-one relationship with the PMT that stores the detailed information of the broadcast program. It corresponds.

  The PMT includes ES PID (Elementary) such as video identification information (Video Stream PID), audio identification information (Audio Stream PID), and time reference information identification information (PCR PID) related to the corresponding broadcast program. PID).

  Therefore, in order to view a broadcast program, first, PAT which is PSI information is acquired, a PMT corresponding to the broadcast program to be viewed is received, an ECM is received with reference to the PMT, a received ECM is sent to the IC card, Performs response processing and descrambler control.

  In the descrambling process, when a part of the components constituting the program is non-scrambled, the program is viewed without performing the descrambling process. Copy control is performed based on the recording control information and PSI / SI information from the IC card. When the recording control information from the IC card cannot be recorded, copy control is performed.

  When receiving and selecting a scrambled program, the ECM PID is obtained from the PMT in the broadcast signal and the ECM is received. The received encrypted ECM is decrypted by giving it to the IC card with an “ECM reception command / response”, and receives a decryption key, viewing control information, and the like.

  If the program (stream) selected from the obtained viewing control information can be viewed, the TS stream packet ID to be descrambled and the decryption key are given to the descrambler.

  Scrambling is performed in units of TS packets, and the usage time of the same key is about several seconds per 1 ECM.

  First, PAT reception is performed, and an NIT (Network Information Table) designated by the PAT is acquired. Therefore, NIT search is executed to obtain physical transmission parameters (frequency, physical channel, etc.) and information on all the organized channels in the network.

  Data such as an individual card ID, CA_systemCA_system_ID, a descrambling decryption key, an initial CBC value, and System_Management_ID is acquired by a command / response executed when the IC card is mounted.

  Execute PAT acquisition processing that is PSI information, receive PMT corresponding to the broadcast program that you want to watch, receive PCM, receive ECM, send received ECM to IC card, process response and control descrambler Do.

  (Digital Broadcasting) The encrypted ECM received by the receiver is given to the IC card, the viewing permission / inhibition determination process is performed, and information such as the decrypted decryption key Ks is obtained. The receiver performs TS descrambling using the obtained decryption key Ks, executes MPEG decoding, decodes video and audio, and outputs video and audio.

  In recent years, with the complexity of functions in digital broadcast receiving apparatuses, the content processed by the CPU increases, and abnormal operations occur in the execution of the program for controlling the execution of signal decoding. In such a case, the CPU generally suspends and reboots (restarts) the abnormally operating program. During the reboot, there was a problem that the car navigation map and the program being watched were interrupted due to the black screen.

  In order to solve the above problem, for example, in the technique disclosed in Patent Document 1, CPU abnormality detection is performed, and recovery by restart is performed. During the restart, the menu screen and the alert screen are presented so as not to become a black screen, but the terrestrial digital broadcast program viewing is not touched. As described above, in a conventional video / audio decoding device such as a digital broadcast receiver that restarts the system when an abnormality is detected, there is a problem that program viewing of the decoded video / audio signal is interrupted.

JP 2001-14006 (paragraphs 0024 to 0044, FIG. 1)

  As described above, a conventional audio / video decoding device such as a digital broadcast receiving device has a last channel for reproducing the viewing of a program when a system reboot occurs for some reason during execution of software for signal decoding. The service ID must be retrieved and the IC card information must be acquired again. When the system is rebooted, an IC card initialization process is required. For this reason, there is a problem that the temporary screen becomes a black screen and video / audio output cannot be performed, and the black screen is displayed and the viewing is interrupted.

  In addition, key information for descrambling the selected transport stream must be obtained again, and there is a problem that the program viewing is interrupted for a long time.

  In addition, since there is no system down sign detection system or record of abnormality history, even if there are similar signs, no countermeasures have been established according to the contents of the abnormality, and only a reboot is performed each time an abnormality occurs. There was a problem of returning after a black screen state over the same time for returning each time.

  The present invention has been made to solve the above problems, and even when the software process is restarted for some reason during the execution of the software process for the signal decoding process, the user can restart the software process. It is an object of the present invention to obtain a video / audio decoding device that can continue to provide continuous viewing without being conscious of.

  According to a first aspect of the present invention, there is provided a video / audio decoding apparatus according to the first aspect, wherein a signal decoding unit that performs a signal decoding process for decoding video / audio on an encoded received video / audio signal, and the signal by the signal decoding unit A control unit that executes a normal task that is an execution control process of the decoding process, and a monitoring unit that obtains abnormality information regarding an abnormality of the normal task being executed based on the operation contents of the signal decoding unit and the control unit, The control unit is capable of executing a degeneration task that is an execution control process of a degenerate decoding process having at least a process of decoding a video with respect to the received video / audio signal, and based on the abnormality information detected by the monitoring unit, When it is determined that the abnormal level related to the regular task is equal to or higher than a predetermined abnormal level, the degenerate task is executed instead of the abnormal task that is the regular task in which the abnormality is detected. There.

  When the control unit of the video / audio decoding device according to claim 1 of the present invention determines that the level is equal to or higher than a predetermined abnormality level based on the abnormality information detected by the monitoring unit, the control unit replaces the abnormal task that is a normal task in which the abnormality is detected. The degenerate task is executed. This degeneration task is an execution control process of a degenerate decoding process including a process of decoding a received video / audio signal into at least a video signal.

  For this reason, the video / audio decoding device according to the first aspect of the present invention allows the user to continuously view the video by performing the video signal decoding process continuously even when the degeneration task is executed instead of the abnormal task. The effect that can continue to provide.

It is a block diagram which shows the structure of the digital broadcast receiver which is Embodiment 1 of this invention. It is explanatory drawing which shows the content of a degeneracy transition type abnormal return system. It is explanatory drawing which showed the flow of the degeneracy state process of FIG. FIG. 6 is an explanatory diagram showing effects of the first embodiment. 10 is a flowchart illustrating an example of a transition change of a processing state according to the second embodiment. FIG. 10 is an explanatory diagram schematically showing storage states of normal state takeover information and degenerate state takeover information in the second embodiment. 10 is a flowchart illustrating an example of a transition change of a processing state according to the third embodiment. It is a flowchart which shows the detail of the degeneration task starting process of FIG. FIG. 10 is an explanatory diagram showing a state of video / audio output in the third embodiment.

<Embodiment 1>
FIG. 1 is a block diagram showing the configuration of a digital broadcast receiving apparatus which is a video / audio decoding apparatus according to Embodiment 1 of the present invention.

  Here, when the digital broadcast receiving apparatus according to the first embodiment receives a terrestrial digital television broadcast, a system down occurs in software processing for signal decoding (regular task) during viewing, and the regular task is restarted The explanation will be focused on.

  As shown in FIG. 1, the digital broadcast receiving apparatus RV according to the first embodiment includes a tuner unit 1, a DEMUX unit 2, a descrambler 3, a video / audio decoding unit 4, a display unit 5, a system control unit 6 (control unit), It comprises a key input unit 7, a remote controller 8, an IC card 9, a system monitoring unit 10 (monitoring unit), and a recording unit 11 (predetermined recording unit).

  As will be described later, the system control unit 6 controls the operation of the tuner unit 1, the descrambler 3, and the display unit 5, and also exchanges information with the IC card 9, the system monitoring unit 10, the DEMUX unit 2, and the key input unit. The entire control operation of the digital broadcast receiving device RV such as information input from 7 is performed.

  The terrestrial digital broadcast signal (high-efficiency-encoded received video / audio signal) received by the antenna is converted into a necessary broadcast signal under the control of the system control unit 6 in the tuner unit 1 in the digital broadcast receiving device RV. Channel selection processing that is reception and selection is performed, packet processing of transmission signals, and error correction processing are performed.

  The DEMUX unit 2 separates necessary packets of the program to be viewed from the TS multiplexed signal obtained from the tuner unit 1, selects a broadcast program signal, and separates various multiplexed data (various SI data, ECM, etc.) .

  The descrambler 3 descrambles a specific packet by the MULTI2 system with respect to the output of the DEMUX unit 2 under the control of the system control unit 6.

  The signal after being selected by the tuner unit 1 and the DEMUX unit 2 decodes (decodes) the video / audio signal encoded and compressed in the MPEG format by the video / audio decoding unit 4. Here, of the decoded video / audio signals, the monitor output OTM which is a video signal is output to the monitor. On the other hand, the decoded video / audio signal is output to a speaker (not shown) or the like as an audio output OTA that is an audio signal.

  The display unit 5 performs display control of menus, lists, messages, and the like for the user on the monitor output OTM under the control of the system control unit 6.

  The remote controller 8 performs an operation input as a user interface. The key input unit 7 performs input processing from the remote controller 8 as input from the user.

  The system control unit 6 controls the entire digital broadcast receiving device RV. Especially for a CA (Conditional Access) module (a module having a function capable of interfacing with the IC card 9), communication with the IC card 9, processing of various data separated from broadcast signals, control of the descrambler 3, and display unit 5 There are control processing, key input processing from the key input unit 7, and the like.

  The IC card 9 is attached to the digital broadcast receiving device RV and communicates with the system control unit 6. As processing that forms the core of the CA system of the digital broadcast receiving device RV, decryption of the received encrypted ECM, viewing control processing of a pay program, and viewing history information management processing are performed.

  The RAM 12 is connected to the system control unit 6 in a readable / writable manner, and stores normal state takeover information 25 and degenerate state takeover information 23 which will be described in detail later. The contents themselves are the same except that the normal state takeover information 25 and the degenerate state takeover information 23 are recorded in the normal state and the degenerate state.

  In the basic operation of selecting and viewing a program, a program to be viewed is selected based on PSI / SI, the TS is selected, and components constituting the program are selected. While sequentially referencing the scramble flag in the TS, the sequentially received ECM is given to the IC card 9 and viewing control is performed according to the response.

  While watching the program, the sequential reference of the scramble flag of the selected TS or the sequentially received ECM is given to the IC card 9, and the viewing control is performed according to the response. The response from the IC card 9 can be viewed, and the user selects a program for viewing.

  The descrambling operation by the descrambler 3 is performed by giving the descrambler 3 a decryption key and a CBC initial value from the system control unit 6 as initial values for decryption. The decryption key and the CBC initial value are read from the IC card 9. The descrambler 3 receives the descrambled TS packet ID and the decryption key from the system control unit 6, and performs descrambling based on the scramble flag and the adaptation field control value of the input TS packet header.

  The system monitoring unit 10 monitors the decoding error occurrence status at the time of decoding from the video / audio decoding unit 4. Further, the memory usage of the system control software processing executed by the system control unit 6 is monitored. The system control software processing means processing by software for controlling signal decoding processing by the descrambler 3 and the video / audio decoding unit 4 which are decoding units.

  The system control software process executed by the system control unit 6 is composed of a plurality of tasks. The system monitoring unit 10 monitors the overflow of the reception buffer for various inter-task messages exchanged between these tasks, the CPU processing load state executing the plurality of tasks, and the operating state of each task.

  The above-described memory usage monitoring, message reception buffer overflow, and the operation state of each task can be normally obtained by the service function of the real-time OS. The CPU processing load can also be monitored by existing technology.

  Here, the CPU (predetermined CPU) means a CPU that performs software processing as the system control unit 6, the system monitoring unit 10, and the like. Also, the driver unit that controls the hardware such as the tuner unit 1, the descrambler 3, the DEMUX unit 2, and the video / audio decoding unit 4 corresponds to software processing that operates on the CPU.

  Based on these monitoring targets, the system monitoring unit 10 records an abnormality history in the storage unit 11 when an abnormality is detected. Further, the detected abnormality information is notified to the system control unit 6. Based on the abnormality information obtained from the system monitoring unit 10, the system control unit 6 performs abnormality level determination processing for each of a plurality of regular tasks, and executes and controls abnormality recovery processing corresponding to the determined abnormality level.

  As one of the abnormal recovery processes, an abnormal task that is determined to be a regular task that needs to be restarted or a degenerate task that operates only during restart of multiple regular tasks including the abnormal task is started. There is an abnormal recovery process that executes this process. This necessary minimum process is a minimum process for continuing program viewing, and performs a descrambling process and a video / audio decoding process.

  The system control unit 6 selects the abnormality recovery processing content based on the abnormality content indicated by the abnormality information. That is, retry control that retries the process that causes the abnormality to be recorded (partial process within the regular task) without causing the regular task to be paused. The error recovery process is either a process (for low-level abnormal levels), a process for restarting abnormal tasks (for a specified abnormal level), or a reset control process for restarting the entire system (for high-level abnormal levels) Choose as. Then, the system monitoring unit 10 performs execution control of the abnormal recovery process of the selected content. When the system control unit 6 executes the reset control process, the degeneration task is executed during the period until the entire apparatus is restarted while executing the reset control process.

  FIG. 2 is an explanatory diagram showing the contents of the degenerate transition type abnormal recovery method. In FIG. 2, the transition of the degenerate transition type abnormal recovery method according to the first embodiment represents a transition from a normal state in which a plurality of normal tasks operate to an abnormal state, the degenerate task is started, and a plurality of normal tasks including abnormal tasks are normal. It shows the state and the flow of processing until returning to the correct execution state.

  Hereinafter, with reference to FIG. 2, the flow of the degenerate transition type abnormal recovery process in the digital broadcast receiving device RV of the first embodiment will be described. The normal transition process 20, the degenerate transition process 27, and the degenerate state process 33 are all executed under the control of the system control unit 6 as well as the process in the normal state 24.

  First, in response to an instruction from the system control unit 6, a series of channel selection and decoding processes by the tuner unit 1, the DEMUX unit 2, the descrambler 3 and the video / audio decoding unit 4 are started, and video / audio signals are normally output. In the normal state 24, viewing is started.

  At this time, the normal takeover information system key, the CBC initial value, the card ID, and the like are recorded as the normal state takeover information 25 in the RAM 12 that records the normal state takeover information 25.

  When an abnormality is detected by the system monitoring unit 10 and abnormality information is given to the system control unit 6 and a transition is made to the degeneration transition 26 according to an instruction from the system control unit 6 based on the abnormality information, a degeneration transition process 27 is performed. In this case, based on the abnormality information, the system control unit 6 determines that the abnormality level related to at least one regular task is at a predetermined abnormality level that needs to be restarted. Hereinafter, for the sake of explanation, a regular task having a predetermined abnormality level that needs to be restarted among a plurality of regular tasks may be referred to as an “abnormal task”, and a regular task other than the abnormal task may be referred to as a “normal regular task”. is there.

  In the degeneracy transition process 27, first, an abnormal task determined to have a predetermined abnormal level is detected, the abnormal task kill 28 is executed so that the abnormal task does not work, and the normal normal task is suspended. A pause (process) 29 is executed.

  At this time, in order to realize continuous viewing, a plurality of regular tasks including a killed abnormal task and a suspended regular task are switched to a degenerate task, and the normal state takeover information 25 is sent to the degenerate processing task activation (process) 30. The degeneration processing task activation 30 is executed, and the video / audio output being viewed is continued using the normal state takeover information 25 sent from the RAM 12.

  When the degeneration process task activation 30 is completed, the state transitions to the degenerate state 31. In the reduced state 31, a reduced state process 33 (a process including a reduced task 24 described later) is executed, and only a process for continuing video and audio is executed.

  Since the decryption key for descrambling the TS being viewed is required even during the degeneration state process 33, the descrambler 42 (see FIG. 3 described later) performs the descrambling process using the normal state takeover information 25. The system key, the CBC initial value, the card ID, etc., which are the takeover information, are recorded even during the degeneration state.

  Then, after completing the abnormal task restart (system reboot), the state transitions to the normal transition 32.

  In the normal transition 32, the normal transition process 20 is executed. Based on the reduced state takeover information 23 recorded in the reduced state, the normal regular task restart (process) 21 is executed. At the same time when the normal normal task restart 21 is executed, the reduction process task kill 22 is executed so that the reduction task does not operate.

  When the normal task restart 21 is completed, the state transitions from the normal transition 32 to the normal state 24, and the above-described operation is performed. In the normal state 24, for example, the system monitoring unit 10 detects an abnormality, determines an abnormality level based on the abnormality information in the system control unit 6, and the system control unit 5 determines a level “3” (a predetermined abnormality level). ) Is issued, the system control unit 6 issues a switching control request to the degeneration task, and the state transition is made to the degeneration transition 26, and the above-described degeneration transition processing 27 is executed.

  As described above, when an abnormal task that causes a system failure that requires a system reboot is detected, the reduced task is activated instead of the regular task including the abnormal task, the reduced task is operated, and the program being viewed is continuously viewed. In the meantime, the abnormal task is restarted (system reboot), and after the system reboot is completed, a series of operations of automatically restarting the normal normal task and returning it to the normal state is automatically executed.

  FIG. 3 is an explanatory diagram showing a flow of the degenerate state process of FIG. As shown in the figure, the degradation state process 33 executes only the video / audio continuation process in the degradation task 34. The degeneration task 34 includes an ECM analysis unit 35 and a decryption key control unit 36. The ECM analysis unit 35 and the decryption key control unit 36 are realized by CPU software processing as processing by the system control unit 6.

  As shown in FIG. 3, the degenerate state processing 33 executes a descrambling process in which the TS selected from the tuner unit 1 of FIG.

  In other words, the TS selected from the tuner unit 1 is input to the Demux LSI 37 and transmitted to the Demux driver 38 to identify the PAT and PMT and output to the ECM analysis unit 35 in the degeneration task 34. Note that the Demux LSI 37 and the Demux driver 38 functionally correspond to the DEMUX unit 2 in FIG.

  The ECM analysis unit 35 receives the PMT corresponding to the broadcast program to be viewed, receives the ECM by referring to the PMT, sends the received ECM to the IC card 40 via the IC card driver 39, and responds with the decryption key and the viewing control information. Are received by the decryption key control unit (scramble key control unit) 36.

  The decryption key control unit 36 transmits a signal based on these pieces of information to the descramble driver 41 and processes it by the descrambler 42. The IC card driver 39 and the IC card 40 functionally correspond to the IC card 9 in FIG. 1, and the descramble driver 41 and the descrambler 42 functionally correspond to the descrambler 3 in FIG.

  If the program (stream) selected from the obtained viewing control information is viewable, the decryption key control unit 36 gives the descrambler 42 the packet ID of the TS stream to be descrambled and the decryption key Ks. If viewing is impossible, control is performed such that the ID and the decryption key Ks are not given.

  Scrambling is performed in units of TS packets, and the usage time of the same key is about several seconds per 1 ECM. Therefore, even in the degenerate state, the decryption key Ks is received every few seconds and the key is updated. As a result, the descrambling process is continuously executed, so that the subsequent process after the descrambling process is continuously executed, and the video / audio output is continued without interruption of the program being viewed.

  While the flow of the degeneration state process 33 is in progress, the abnormal task restart process (system reboot process) 43 of the detected abnormal task and the normal normal task pause process 44 are executed in parallel, so that the user can continue watching even during the reboot.

  As described above, when the system control unit 6 of the digital broadcast receiver RV according to the first embodiment determines that the level is equal to or higher than the predetermined abnormality level (level 3) based on the abnormality information detected by the system monitoring unit 10, an abnormality is detected. A degenerate task is executed in place of a plurality of regular tasks including the abnormal task. This degeneration task is an execution control process of a degenerate state process 33 (degenerate decoding process) having a process of decoding a digital broadcast signal, which is a highly efficient encoded video / audio signal, into a video / audio signal.

  For this reason, the digital broadcast receiving apparatus according to the first embodiment allows the user to perform video and audio signal decoding processing continuously even when a degeneration task is executed instead of an abnormal task. There is an effect that it is possible to continue to provide continuous audio viewing.

  FIG. 4 is an explanatory diagram showing the effect of the first embodiment. As shown in (a) of the figure, when a normal task is restarted conventionally, it takes a relatively long time to restart the normal task. Therefore, the normal task restart including the abnormal task is started from the image V11 before the abnormal task occurs. A black display image V12 occurs between the subsequent images V13 during a period in which it cannot be ignored.

  On the other hand, as in the digital broadcast receiving apparatus of the first embodiment, a degenerate task is executed instead of a regular task when an abnormal task occurs. As a result, as shown in FIG. 4B, the normal image V22 can be displayed between the image V21 before the occurrence of the abnormal task and the image V23 after the normal task restart including the abnormal task.

  In addition, the system monitoring unit 10 of the digital broadcast receiving apparatus according to the first embodiment performs the audio / video signal decoding in the signal decoding process by the execution of the signal decoding units (DEMUX unit 2, descrambler 3 and video / audio decoding unit 4). Abnormal information is detected based on an error occurrence state and a processing state of at least one software process that realizes a regular task. As described above, the processing state of at least one software process includes the overflow of the reception buffer of various inter-task messages exchanged between tasks, the CPU processing load state executing a plurality of tasks, This corresponds to the operating state.

  For this reason, the system control unit 6 can accurately determine the abnormal state of the regular task based on the abnormality information from the system monitoring unit 10.

  In addition, since the digital broadcast receiving device RV of the first embodiment detects abnormality information including abnormality history information accumulated in the recording unit 11, the system control unit 6 determines the abnormal state of the regular task based on the abnormality information. Predictive judgment can be made in advance. As a result, by performing the abnormal recovery process before a major failure occurs, it is possible to avoid a long-term video and audio stoppage due to a long-time abnormal recovery process in the event of a serious failure. It should be noted that the abnormality sign means a sudden increase in abnormality occurrence frequency or a case where the total number of abnormality occurrences exceeds a certain level.

  Furthermore, the system control unit 6 of the digital broadcast receiving apparatus RV according to the first embodiment executes a retry control process when it is determined that the abnormality level is lower than the predetermined abnormality level based on the abnormality information. As a result, the abnormal state can be resolved without suspending the regular task.

  In addition, the system control unit 6 of the digital broadcast receiving device RV according to the first embodiment executes the reset control process when determining that the abnormality level is higher than the predetermined abnormality level based on the abnormality information. Thus, the abnormal state can be resolved.

  Further, since the degenerate state process 33 (degenerate decoding process) in the digital broadcast receiving device RV of the first embodiment includes a decrement descramble process (process by the descrambler 42), even when the digital broadcast signal includes a scramble signal, There is an effect that it is possible to continue to provide the user with continuous viewing of the video based on the scramble signal.

  Furthermore, in the digital broadcast receiving apparatus according to the first embodiment, the degeneration / decryption process acquires key information (decryption key Ks) from the normal state takeover information and executes the degeneration scramble process. Therefore, the degeneration scramble is always stable. Processing can be executed.

<Embodiment 2>
FIG. 2 also shows the characteristics of the second embodiment and shows the state in the RAM 12 of FIG. In the second embodiment, as will be described later, the normal state takeover information 25 recorded in the normal state 24 of FIG. 2 and the degenerate state takeover information 23 recorded when the user continues to watch in the degenerate state are stored in the RAM 12 respectively. It is stored twice in another area. As a result, even when an abnormality occurs in which a part of the takeover information storage area is destroyed due to a memory leak or the like, it is possible to continue decoding and descrambling during rebooting using the other takeover information storage area.

  FIG. 5 is a flowchart showing a transition change example of the processing state according to the second embodiment, which is executed by the system control unit 6. The configuration and operation of the second embodiment are the same as those of the first embodiment shown in FIGS. Hereinafter, the case where the state changes according to the state change example shown in FIG. 5 will be described with reference to FIG.

  Normally, when viewing a digital broadcast program, the system is in the normal state of step S20. In this case, in step S21, the system key (scramble key Ks), the CBC initial value, and the card ID as the takeover information are recorded as the normal state takeover information 25 in the normal state recording area 13 (see FIG. 6) of the RAM 12.

  In step S22, when a system abnormality is detected by the system monitoring unit 10, when it is determined that the abnormal level is “3” (predetermined abnormal level) or more and it is necessary to restart the regular task, the degenerate transition process is performed in step S23. The degeneration transition process 27 shown in FIG. 2 is executed. At this time, descrambling is executed based on the normal state takeover information 25 recorded in the normal state recording area 13 in step S21, and the program being viewed is continued.

  After that, even if the degeneration state of step S24 is entered, the decoding process is continued in the degeneration task 34. Then, in step S25, the decryption key Ks, the CBC initial value, and the card ID, which are the transfer information at this time, are recorded as the degenerate state transfer information 23 in the degenerate state recording area 14 (see FIG. 6) of the recording unit 11.

  Thereafter, in step S26, the detection of the abnormal task and the restart of the abnormal task are completed, the normal transition process 20 shown in FIG. 2 is started, and when the normal normal task is resumed, the normal state of step S20 is restored.

  In addition, when the normal task that is the normal processing means is restarted, the reduced state takeover information 23 is handed over to the normal task from the reduced task that is the return-only processing means, and the operation of the reduced task can be stopped. After that, video / audio output continues without any problem.

  Also, since the decryption key Ks for descrambling is updated within a few seconds, the video / audio decoding process can be performed without interruption, and the subsequent processing can be continued, enabling continuous viewing. ing.

  The processing procedure shown in FIG. 5 described above is common to the first and second embodiments. However, the points described below are different in the second embodiment.

  FIG. 6 is an explanatory diagram schematically showing a storage state of normal state takeover information and degenerate state takeover information in the digital broadcast receiving apparatus of the second embodiment.

  As shown in the figure, the normal state takeover information 25a and 25b having the same contents respectively recorded in the normal state 24 are stored in the partial storage areas 13A and 13B which are separate areas in the normal state recording area 13. Similarly, the reduced state takeover information 23a and 23b having the same contents recorded when the user continues to watch in the reduced state is stored in the partial storage areas 14A and 14B which are different areas in the reduced state recording area 14.

  In this way, the normal state takeover information 25a and 25b and the degenerate state takeover information 23a and 23b are respectively stored twice in different areas (13A, 13B and 14A, 14B) of the RAM 12. For this reason, even when the information (for example, normal state takeover information 25a, degenerate state takeover information 23a) in one takeover information storage area is abnormal due to a memory leak or the like, information in the other takeover information storage area (for example, The decoding and descrambling processing can be continued without any trouble by executing the degenerate task in the reboot period until the abnormal task is restarted by the substitute data obtained from the normal state takeover information 25b and the degenerated state takeover information 23b). .

  Further, instead of the configuration in which the normal state recording area 13 and the degenerate state recording area 14 are provided in the RAM 12, the RAM 12 is provided as a mutually independent recording medium having the normal state recording area 13 and the degenerate state recording area 14, and the normal state takeover information 25a, 25b is provided. May be managed by one recording medium having the normal state recording area 13, and the degenerated state handover information 23 a and 23 b may be managed by the other recording medium having the degenerated state recording area 14.

  As described above, the digital broadcast receiving apparatus according to the second embodiment stores a plurality of normal state takeover information 25a and 25b and degenerate state takeover information 23a and 23b in different recording areas. Therefore, even when one of the normal state takeover information 25 (any one of 25a and 25b) or the degenerate state takeover information 23 (any one of 23a and 23b) is destroyed, the other not destroyed By using the normal state takeover information 25 or the degenerate state takeover information 23, there is an effect that the degeneration scrambling process can be executed with high stability.

<Embodiment 3>
FIG. 7 is a flowchart illustrating an example of a change in processing state transition according to the third embodiment. FIG. 8 is a flowchart showing details of the degenerate task activation process of FIG. The configuration and operation of the third embodiment are the same as the contents of the first embodiment shown in FIGS. Hereinafter, the case where the state changes according to the state change examples shown in FIGS. 7 and 8 will be described with reference to FIGS. 1, 2, 7 and 8.

  As shown in FIG. 7, in the normal state of step S30, the normal state takeover information 25 is sequentially recorded in the RAM 12 (step S31).

  Then, an abnormality occurs in step S32. For example, if an abnormality with an abnormal level “3” occurs in step S32 in an audio task that performs audio decoding output processing, etc., an abnormality in the audio task (abnormal level “3”) is detected in step S33, and degraded as an abnormal recovery process. The transition process 27 is started.

  That is, in Step S34, the abnormal voice task Kill and restart are started, and the normal normal task is suspended in Step S35. Further, in step S36, a degeneration process task activation process is performed.

  As shown in FIG. 8, in the degeneration task activation process (S36), first, in step S37, the degeneration task acquires the normal state takeover information 25.

  Thereafter, in step S38, during the degeneration processing until the audio task is restarted, subtitle decoding display processing accompanying subtitle decoding processing is performed instead of audio output, and further, a combination of video decoding processing and descrambling processing is performed. The minimum degeneration processing is performed by video output and subtitle output.

  Returning to FIG. 7, when the restart of the voice task that was an abnormal task is completed (S40), the normal normal task is resumed in the normal transition process (S41), and the degenerate state is taken over by all the normal tasks including the voice task. The information 23 is passed (S42), the degenerate task is killed (S43), and the normal state is restored (S20).

  FIG. 9 is an explanatory diagram showing the effect of the third embodiment. The digital broadcast receiving apparatus according to the third embodiment executes a degenerate task capable of executing caption decoding display processing instead of the audio task when an abnormal audio task occurs.

  As a result, as shown in FIG. 9A, from the output of the sound A31 and the image V31 before occurrence of the abnormal task, as shown in FIG. 9C, the sound A33 and the image V33 after the normal task is restarted. Even in the degenerate task execution period, which is a period until output, a normal image L32 with subtitle L32 can be displayed as shown in FIG.

  As described above, since the digital broadcast receiving apparatus according to Embodiment 3 performs subtitle decoding during the restart of an abnormal audio task, even if the audio task is an abnormal task, the subtitle and video can be displayed to the user. There is an effect that it is possible to continue to provide continuous viewing accompanied by.

<Application to method invention>
The digital broadcast receiving method of the present invention described in the first to third embodiments is a dedicated restoration method that performs only the decoding process and the descrambling process in parallel with the reboot of the abnormal task when it is determined that the reboot is necessary. By executing the step of starting the degenerate task, when decoding, the degenerate task is executed during the system reboot based on the system key, the CBC initial value, and the card ID, which are the normal state takeover information 25, and video / audio output is continued. It is characterized by making it executable.

  That is, the digital broadcast receiving method, which is a video / audio decoding method common to the first to third embodiments, is a signal decoding unit 2 to 4 that executes a signal decoding process for decoding video / audio on a digital broadcast signal. A digital broadcast receiving method using a digital broadcast receiving apparatus having the following steps (a) to (c):

  (a) Under normal control of the system control unit 6, a normal task that is an execution control process of the signal decoding process by the signal decoding unit is executed at a normal time.

  (b) The system monitoring unit 10 obtains abnormality information related to the abnormality of the regular task being executed based on the operation contents of the signal decoding unit and the step (a).

  (c) If it is determined that the abnormal level related to the regular task is equal to or higher than a predetermined abnormal level (level “3”) based on the abnormal information detected in step (b), the process of step (a) is stopped. Instead, execute the degenerate task. The degeneration task executed in step (c) includes an execution control process of a degenerate decoding process including a process of decoding a digital method signal into at least a video signal.

  When the above-described digital broadcast receiving method determines that the abnormality level is equal to or higher than a predetermined abnormality level based on the abnormality information detected in step (b) when the step (c) is executed, A degenerate task is executed instead of a task.

  For this reason, the above digital method receiving method allows the user to continue viewing by performing the video signal decoding process continuously even when the degeneration task is executed instead of the abnormal task in step (c). The effect that can continue to provide.

  1 tuner unit, 2 DEMUX unit, 3 descrambler, 4 video / audio decoding unit, 5 display unit, 6 system control unit, 7 key input unit, 8 remote controller, 9 IC card, 10 system monitoring unit, 11 recording unit, 33 degeneration State processing, 34 degenerate task, 35 ECM analysis unit, 36 decryption key control unit, 43 abnormal task restart processing, 44 normal normal task pause processing.

Claims (11)

A signal decoding unit that performs a signal decoding process for decoding video / audio with respect to the encoded received video / audio signal;
A control unit that executes a regular task that is an execution control process of the signal decoding process by the signal decoding unit;
Based on the operation contents of the signal decoding unit and the control unit, a monitoring unit that obtains abnormality information related to abnormality of the regular task being executed,
The controller is
For the received video / audio signal, a degeneration task that is an execution control process of a degenerate decoding process having a process of decoding at least a video can be executed,
Based on the abnormality information detected by the monitoring unit, when it is determined that an abnormality level related to the regular task is equal to or higher than a predetermined abnormality level, the degenerate task is executed instead of the abnormal task that is the regular task in which an abnormality is detected. It is characterized by
Video / audio decoding device. The video / audio decoding device according to claim 1,
The regular task is realized by at least one software process executed by a predetermined CPU using a memory,
The operation contents of the signal decoding unit and the control unit include an error occurrence state at the time of decoding the audio / video signal in the digital signal decoding process executed by the signal decoding unit, and a processing state of the at least one software process. ,
Video / audio decoding device. The video / audio decoding device according to claim 1 or 2,
The monitoring unit records the detected abnormality information as a history of abnormality in a predetermined recording unit,
The abnormality information includes abnormality history information that is a history of the past abnormality information recorded in the predetermined recording unit,
Video / audio decoding device. The video / audio decoding device according to any one of claims 1 to 3,
The abnormality information includes information instructing partial processing of the regular task that is the source of the abnormality,
The controller is
Retry control processing for executing again the partial processing of the regular task can be further executed,
Based on the abnormality information detected by the monitoring unit, when it is determined that the abnormality level related to the regular task is a low-level abnormality level with the predetermined abnormality level being low, the retry control process is executed.
Video / audio decoding device. The video / audio decoding device according to any one of claims 1 to 4,
The controller is
A reset control process that restarts the entire device can be further executed,
If it is determined that the abnormal level related to the regular task is the predetermined abnormal level based on the abnormal information, the degenerate task is executed until the abnormal task is resumed normally,
Based on the abnormality information, when it is determined that the abnormality level related to the regular task is an advanced abnormality level having an abnormality degree higher than the predetermined abnormality level, the entire apparatus is restarted while executing the reset control process. Execute the degenerate task for a period of time until
Video / audio decoding device. The video / audio decoding device according to any one of claims 1 to 5,
The received video / audio signal includes a scrambled scrambled signal;
The signal decoding unit includes a descrambler that descrambles the scrambled signal,
The degeneracy decoding process includes a degeneration descrambling process for descrambling the scramble signal,
Video / audio decoding device. The video / audio decoding device according to claim 6,
The signal decryption unit sequentially stores key information necessary for the descrambler processing in a predetermined storage unit as normal state takeover information,
The degenerate decryption process acquires the key information from the normal state takeover information and executes the degenerate scramble process;
Video / audio decoding device. The video / audio signal decoding device according to claim 7,
The normal state takeover information includes a plurality of normal state takeover information of the same content, and the plurality of normal state takeover information is stored in different recording areas, respectively.
Video / audio decoding device. The video / audio decoding device according to any one of claims 1 to 8,
The degenerate decoding process includes a decoding process of a video / audio signal based on the received video / audio signal,
Video / audio decoding device. The video / audio decoding device according to any one of claims 1 to 8,
The degenerate decoding process includes a decoding process of a caption signal based on the received video / audio signal,
In the degenerate decoding process, when the regular task determined to be the abnormal task is an audio task, the subtitle signal is decoded instead of the audio signal.
Video / audio decoding device. A video / audio decoding method in a video / audio decoding apparatus having a signal decoding unit that executes a signal decoding process for decoding video / audio with respect to an encoded received video / audio signal,
(a) executing a regular task that is an execution control process of the signal decoding process by the signal decoding unit at a normal time;
(b) Based on the operation content of the signal decoding unit and the step (a), obtaining abnormal information regarding abnormality of the regular task being executed;
(c) Based on the abnormality information detected in the step (b), when it is determined that the abnormality level related to the regular task is equal to or higher than a predetermined abnormality level, the processing of the step (a) is stopped, and instead the degenerate task The degeneration task includes an execution control process of a degenerate decoding process including a process of decoding the received video / audio signal into at least a video signal.
Video / audio decoding method.

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