JP5366470B2 - Receiving machine - Google Patents

Description

  The present invention relates to a receiver that receives a digital broadcast.

  In digital broadcasting, data called a section is transmitted in addition to video data and audio data. The section is one of formats that can be transmitted in the transport stream, and PSI (program specific information) and SI (program sequence information) are transmitted in this format. Channel selection is performed at the receiver using the information in the section.

  The general processing flow at the time of channel selection in digital broadcasting is shown below. When the channel number is input, the received channel number is converted into a service ID. Subsequently, it is checked whether the service ID is included in the currently received PAT (Program Association Table). If the service ID is not included in the currently received PAT, the frequency corresponding to the service ID is checked from the NIT (Network Information Table), and the reception frequency is changed. When the service ID is included in the currently received PAT, the PID (packet identifier) of the corresponding PMT (Program Map Table) is acquired from the PAT, and the PMT is received. Further, a PID such as a video signal or an audio signal is acquired from the received PMT, and a TS packet corresponding to the PID is selected and sent to the decoding unit. In the decoding unit, video and audio are decoded.

  On the other hand, when transmitting a digital signal, transmission reliability is improved by performing error correction coding on transmission data or adding an error detection code. In digital broadcasting, the transmission side adds CRC32 as an error detection code to a section. Also, a checksum is added as an error detection code to a DSM-CC section whose section syntax display is 0 among the sections. If there is a contradiction between the received data and the added error detection code, the receiving side considers that the communication has failed and discards the received data.

  As a recovery measure when an error occurs in a section, for example, a technique for minimizing error propagation by correcting the effective data length of the section (see Patent Document 1), or what number of packet in the section A technique for reconstructing section information in a short time by estimating (see Patent Document 2) is disclosed.

Japanese Patent Laid-Open No. 10-313281 JP 2006-042275 A

  If it is determined that there is an error in the section by the error detection code, the data determined to be incorrect may be discarded during normal times and the next data may be waited. This is because the section is repeatedly transmitted at a predetermined period, and therefore, if data acquisition is continued for a certain period of time, data for one period necessary for channel selection of the receiver can be acquired.

  However, in some cases, an error detection code having an incorrect value may continue to be added due to a defect on the transmission side or a setting error. In that case, since the value of the error detection code added on the transmission side does not match the value generated on the reception side, even if the received data is correct, it is discarded as incorrect data. As a result, data for one cycle necessary for channel selection of the receiver cannot be acquired and channel selection operation cannot be performed. Therefore, while an inappropriate error detection code is added, It becomes impossible to watch. Furthermore, even if the transmission side is modified so that an appropriate error detection code is added later, re-broadcasting of a program that could not be viewed is not necessarily performed. This way. Furthermore, since the method described in Patent Document 1 and the method described in Patent Document 2 are recovery methods after an error has occurred, it is impossible to deal with such a case where error detection does not function correctly.

  The present invention has been made in view of such a conventional problem. Even when the transmitting side continues to add an inappropriate error detection code, the validity of the data is verified. It aims at providing the receiver which outputs a sound.

The receiver according to the present invention is a receiver that receives digital broadcasts, and includes a control unit that controls the operation of the receiver itself, an operation state analysis unit that analyzes the operation state of the control unit, and an error detection code included in the received data. And a decoding unit that determines an error, and an error detection code defect determination unit that determines whether an incorrect error detection code is added to the received data. The error detection code defect determination unit includes an error determined by the decoding unit. Based on the error rate calculated based on the received power and the reception level calculated from the received power of the digital broadcast, it is determined whether an error in the error detection code has occurred instead of a transmission error. without discarding the received data it is determined that there is, only when the error in the error detection code is determined to have occurred not transmission error, received data that was not discarded The a, after performing treatment tuning operation as a normal data is not determined Rigaaru erroneous Te decode unit smell, the image and audio data included in the received data based on the analysis result of the operation state analyzer output Take control.

  According to the present invention, the receiver can determine the validity of the received data by the operation state analysis unit. Therefore, even when the transmitting side transmits data with an incorrect error detection code, if the data other than the code is valid, the receiver performs normal processing on the data, and the program Can be viewed.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

<Embodiment 1>
(Constitution)
FIG. 1 is a block diagram showing a configuration of a receiver 1 that receives a digital broadcast according to the present embodiment. The receiver 1 includes a tuner unit 11, a demodulation unit 12 connected to the tuner unit 11, a decoding unit 13 connected to the demodulation unit 12, a video output unit 17 and an audio output unit 18 connected to the decoding unit 13. The decoding unit 13 includes a TS decoding unit 14, a video decoding unit 15 connected to the TS decoding unit 14, and an audio decoding unit 16. The TS decoding unit 14 includes a demodulation unit 12, a video decoding unit 15 includes a video output unit 17, The audio decoding unit 16 is connected to the audio output unit 18. The TS decoding unit 14 has a function of acquiring an error detection code included in received data and determining an error.

  In addition, the receiver 1 includes a control unit 19 that controls the operation in the receiver itself. The connection unit 19 includes a TS unit 11, a demodulation unit 12, a video output unit 17, an audio output unit 18, and a TS decode in the decoding unit 13. Are connected to the unit 14, the video decoding unit 15, and the audio decoding unit 16. The receiver 1 further includes an operation state analysis unit 21 that analyzes the operation states of the memory 20 and the control unit 19, and is connected to the control unit 19.

(Operation)
Next, the operation of the receiver 1 according to this embodiment will be described.

  First, for the operation of the entire receiver 1, the tuner unit 11 outputs the selected broadcast signal to the demodulation unit 12. The demodulator 12 demodulates the input signal into a digital signal and outputs it to the TS decoder 14 as a TS packet. The TS decoding unit 14 separates input data into video TS packets and audio TS packets by the PID filter set by the control unit 19, and outputs the video data to the video decoding unit 15 and the audio data to the audio decoding unit 16. To do. The contents of the section packet are notified to the control unit 19.

  The video decoding unit 15 performs decoding processing on the video data, and then outputs the decoded signal to the video output unit 17. The video output unit 17 displays the video externally. The audio decoding unit 16 performs a decoding process on the audio data, and then outputs the decoded signal to the audio output unit 18. The audio output unit 18 outputs audio to the outside. Information regarding the channel selection operation in the TS decoding unit 14, the video decoding unit 15, and the audio decoding unit 16 and the channel selection operation in the control unit 19 is passed to the operation state analysis unit 21 via the control unit 19.

  FIG. 2 is a flowchart showing the flow of the channel selection operation in the receiver 1 in particular.

  When the viewing channel number is input, the control unit 19 converts the received channel number into a service ID (step S11). Subsequently, it is checked whether the service ID is included in the currently received PAT stored in the memory 20 or the like (step S12). If the service ID is not included in the currently received PAT, the frequency corresponding to the service ID is checked from the NIT, and the reception frequency is changed (step S13). If the service ID is included in the currently received PAT, the PID of the corresponding PMT is acquired from the PAT.

  Regarding the acquisition of PAT and PMT, the TS decoding unit 14 notifies the control unit 19 when the PAT packet is acquired. In addition, the control unit 19 acquires the PMT PID from the PAT, and sets the TS decoding unit 14 to notify the control unit 19 when the PMT having the PID is acquired. That is, the TS decoding unit 14 notifies the control unit 19 in the same manner when a PMT packet is acquired. In addition, the TS decoding unit 14 performs error detection on a packet in a section such as PAT or PMT. The operation when an error is detected will be described later.

  The control unit 19 acquires a PID such as a video signal or an audio signal from the PMT. Further, the TS decoding unit 14 is set so as to acquire packets having those PIDs (step S15) and output them to the video decoding unit 15 and the audio decoding unit 16. When the TS decoding unit 14 acquires the video data or audio data packet having the set PID, the TS decoding unit 14 sends the video data or audio data packet to the video decoding unit 15 and the audio decoding unit 16, respectively. The video decoding unit 15 and the audio decoding unit 16 decode the video and audio (step S16).

  The flowchart of FIG. 3 shows processing that is called when the TS decoding unit 14 determines that there is an error in the received data based on the error detection code of the packet of the section.

  In the present embodiment, the control unit 19 treats data in which an error is detected as normal data, and continues the channel selection operation shown in the flowchart of FIG. 2 using information described in the received data (step S21). . Information on the channel selection operation is transferred from the control unit 19 to the operation state analysis unit 21, and the operation state analysis unit 21 determines whether the channel selection operation is normally performed based on the information (step S22). When the operation state analysis unit 21 determines that the channel selection operation is normally performed, the operation state analysis unit 21 notifies the control unit 19 of the fact, and the control unit 19 outputs the video / audio according to the determination, An instruction is issued to the voice output unit 18 (step S23). That is, the control unit 19 performs a channel selection operation based on the information of the reception data even when the decoding unit 13 determines that the error is present, and the image data included in the reception data based on the analysis result of the operation state analysis unit 21. Perform output control.

  Note that the operation state analysis unit 21 determines that the channel selection operation is normally performed. For example, the TS decoding unit 14 and the control unit 19 may use video / audio packets generated by the channel selection operation as shown in FIG. It may be determined whether or not the acquisition has been performed continuously for a certain time or more, or whether or not the video decoding unit 15 has succeeded in decoding the macroblocks in the image at a certain rate or more. In the former, there is a possibility that the output image sound may be disturbed because the determination of the decoding result is not performed, but the processing load required for the analysis of the operation state can be reduced. In the latter, since the decoding state for each image is monitored, the processing load required for the analysis of the operation state is large. However, since the decoding processing result is confirmed, the output image sound can be prevented from being extremely disturbed.

(effect)
In the first embodiment, the receiver 1 can determine the legitimacy of the received data by the operation state analysis unit 21, and if the operation state analysis unit 21 determines that the channel selection operation is not performed correctly, the receiver 1 selects the receiver data. Since the station operation is stopped, the error-detected received data, which has been conventionally discarded so as not to cause an unexpected malfunction in the receiver, can be used for the channel selection operation shown in the flowchart of FIG. Therefore, when the error-detected data includes normal data, the processing up to the output of the video and audio can be performed as usual. Therefore, when the transmission side adds an incorrect error detection code, the error detection code It is possible to solve the problem of the prior art that it becomes impossible to view even if other data is correct.

<Embodiment 2>
(Constitution)
FIG. 4 is a block diagram showing a configuration of receiver 2 that receives the digital broadcast according to the present embodiment. In the present embodiment, an error detection code failure determination unit 22 that determines whether there is a failure in setting an error detection code is connected to the control unit 19. The error detection code defect determination unit 22 has a function of acquiring the signal power of the tuner unit 11 and the error occurrence status in the TS decoding unit 14 via the control unit 19. Other configurations are the same as those of the receiver 1 described in Embodiment 1, and thus detailed description thereof is omitted here.

(Operation)
Next, the operation of the receiver 2 according to the present embodiment, particularly when an error is detected, will be described. The flowchart of FIG. 5 shows processing that is called when the TS decoding unit 14 determines that there is an error in the received data based on the error detection code of the packet in the section.

  In the second embodiment, when it is determined in the TS decoding unit 14 that the data received during the channel selection operation is an error, the error detection code defect determination unit 22 determines whether the data has been acquired from the control unit 19 in the past certain period. The error rate is calculated. Further, the reception level is calculated from the signal power acquired from the tuner 11, and it is determined whether the error rate is too high for the reception level (steps S31 and S32).

  If it is determined that the error rate is within the assumed range, the error detection code defect determination unit 22 simply determines that a transmission error has occurred, and notifies the control unit 19 to that effect. The control unit 19 discards the received data according to the notification from the error detection code defect determination unit 22 (step S33). If the error rate is higher than the value assumed from the reception level, the error detection code failure determination unit 22 determines that there is a failure in the setting of the error detection code and notifies the control unit 19 to that effect. The control unit 19 continues the channel selection operation by handling the error detected data as normal data in accordance with the notification from the error detection code defect determination unit 22 (step S34).

  After that, as in the first embodiment, information regarding the channel selection operation is passed from the control unit 19 to the operation state analysis unit 21, and the operation state analysis unit 21 performs the channel selection operation normally based on the information. (Step S35). When the operation state analysis unit 21 determines that the channel selection operation is normally performed, the operation state analysis unit 21 notifies the control unit 19 of the fact, and the control unit 19 outputs the video / audio according to the determination, An instruction is given to the audio output unit 18 (step S36). That is, only when it is determined that there is a problem with the setting of the error detection code, the control unit 19 performs the channel selection operation based on the information of the received data even when the decoding unit 13 determines that there is an error. Based on the analysis result of the analysis unit 21, the output control of the image data included in the reception data is performed.

  Since other operations are the same as those in the first embodiment, a detailed description thereof is omitted here.

(effect)
In the second embodiment, the processing after error detection is processed separately when it is determined that a transmission error has occurred before performing the channel selection operation and when it is determined that there is a problem with the setting of the error detection code. Yes. Therefore, when a transmission error occurs simply due to a low reception level, resources can be allocated to processing corresponding to the transmission error.

  In the present embodiment, the material that the error detection code defect determination unit 22 determines that there is a possibility of a defect in the error detection code that is sent is that the error rate is too high with respect to the reception level. Other than that, it is sufficient if the error occurrence state satisfies a certain condition. For example, it may be a material for determining that an error has occurred continuously for a certain number of times.

  In Embodiments 1 and 2, the error detection code added to the data may be any code that adds a redundant bit generated from the data after the data. For example, besides the CRC, a checksum, a Hamming code, or the like may be used.

  In the first and second embodiments, when the receivers 1 and 2 treat the data in which the error is detected as normal data and perform the channel selection operation, the viewer is notified that the receiver is operating in a special mode. May be. That is, when performing a channel selection operation when the decoding unit 13 determines that there is an error, the control unit 19 may perform control to notify the viewer that there is an error in the received data. One example of the notification method is to display a character string indicating that the display is operating in a special mode. By notifying the viewer, when the image sound is disturbed, the viewer can know that the disturbance is not a failure of the receiver and that there is a possibility that the transmission data is defective.

  In the first and second embodiments, the viewer may be able to select whether or not to enter a special mode in which error-detected data is handled as normal data. As an example of a method for the viewer to select, there is a method for displaying a dialog on the display screen. Thereby, it is possible to cope with a viewer who does not want to view using the method of the first and second embodiments.

It is a block diagram which shows the structure of the receiver which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the receiver which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the receiver which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the receiver which concerns on Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the receiver which concerns on Embodiment 2 of this invention.

Explanation of symbols

  1 receiver, 11 tuner unit, 12 demodulation unit, 13 decoding unit, 14 TS decoding unit, 15 video decoding unit, 16 audio decoding unit, 17 video output unit, 18 audio output unit, 19 control unit, 20 memory, 21 operation State analysis unit, 22 Error detection code defect determination unit.

Claims (2)

A receiver for receiving digital broadcasting,
A control unit that controls the operation of the receiver itself;
An operation state analysis unit for analyzing an operation state of the control unit;
A decoding unit that acquires an error detection code included in received data and determines an error;
An error detection code defect determination unit that determines whether or not the error detection code that is not correct is added to the received data ,
The error detection code failure determination unit determines whether the error of the error detection code is based on an error rate calculated based on the error determined by the decoding unit and a reception level calculated from reception power of the digital broadcast. Determine if it was not a transmission error,
The control unit does not discard the received data determined to have the error in the decoding unit, and does not discard only when it is determined that an error in the error detection code has occurred instead of the transmission error . The received data itself is treated as normal data that is not judged to have the error in the decoding unit, and after performing a channel selection operation, an image included in the received data based on an analysis result of the operation state analyzing unit. Control the output of sound data,
Receiving machine. The control unit performs control to notify a viewer that there is an error in the received data when the channel selection operation is performed by treating the received data itself that has not been discarded as the normal data.
The receiver according to claim 1.

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