JP5284733B2 - Digital broadcast receiving apparatus and digital broadcast receiving method - Google Patents

Description

  The present invention relates to a digital broadcast receiving apparatus and a digital broadcast receiving method that are mounted on a mobile body and receive and decode a digital broadcast, and particularly when a program cannot be received on a channel that has been received so far due to movement. The present invention relates to a digital broadcast receiving apparatus and a digital broadcast receiving method for switching to another channel that broadcasts a program having the same content.

  In the conventional digital broadcast receiving apparatus, when a program cannot be received on a channel that has been received up to that point, a program having the same content (hereinafter, sometimes referred to as “the same program”) is broadcast on another channel. If a channel on which the same program is broadcast is found, the channel is switched to another channel on which the same program is broadcast. However, there is a problem that the program that was being watched is interrupted until a channel on which the same program is broadcast is found by the search.

  In order to solve the above-mentioned problem, for example, two systems capable of receiving digital broadcasts are provided, one channel receives a channel of a program viewed by a user, and the other system receives a program viewed by the user. Technology that displays the program of the channel received by the other channel when the channel of the program being viewed by the user cannot be received when another channel on which the same program is broadcast is received. (For example, see Patent Documents 1 and 2).

JP 2001-077712 A JP 2006-0667402 A

  The ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) standard for digital terrestrial broadcasting in Japan is weak against noise or multipath, but weakly transmitted programs with high quality video and audio, and noise or multipath. However, strong hierarchical transmission programs with low quality video and audio are transmitted on the same physical channel. The program of strong layer transmission can receive a wider area than the program of weak layer transmission.

  For example, it is assumed that a program transmitted from at least one of a first broadcast station and a second broadcast station on which the same program is broadcast is received at six points, in other words, at first to sixth points. . The first to sixth points are on a straight line, and a predetermined interval is provided between the points. Here, the first point is a point where the first broadcast station's weak layer transmission program and the strong layer transmission program can be received, and the second point is the first broadcast station's strong layer transmission program which can be received. The third point is a point at which a program of strong hierarchical transmission of the first broadcasting station and a program of strong hierarchical transmission of the second broadcasting station can be received. The fourth point is a point where the second broadcast station can receive the strong layer transmission program, and the fifth and sixth points can receive the second broadcast station's weak layer transmission program and the strong layer transmission program. It is a point. Also, a weak layer transmission program and a strong layer transmission program transmitted from each broadcasting station on the same physical channel are programs having the same contents.

  Consider a case where a mobile object moves from a first point to a sixth point. Patent Documents 1 and 2 do not disclose which of the weak hierarchical transmission program and the strong hierarchical transmission program is received. For example, the weak hierarchical transmission program is disclosed by the methods disclosed in Patent Documents 1 and 2. When the program is received from the first point to the second point, the weak broadcast transmission program of the first broadcast station is interrupted. And the program of the weak hierarchy transmission of a 2nd broadcasting station cannot be received until it moves to a 5th point. Therefore, there is a problem that a weak layer transmission program cannot be viewed until the moving body moves from the second point to the fifth point.

  In addition, when receiving a program of strong hierarchical transmission by the method disclosed in Patent Documents 1 and 2, the strong hierarchical transmission of the first broadcast station or the second broadcast station is performed until the program moves from the second point to the fifth point. Can be received. However, since only a program of strong hierarchical transmission can be received, it is low even in an area where a program of weak hierarchical transmission of the first broadcasting station can be received and an area where a program of weak hierarchical transmission of the second broadcasting station can be received. There is a problem that only a program of strong hierarchical transmission composed of quality video and audio can be viewed.

  Further, in the above-described example, it is assumed that the program of strong layer transmission and the program of weak layer transmission transmitted in the same physical channel have the same contents, but in strong layer transmission and weak layer transmission, Broadcasting programs with different contents is also allowed. That is, there is a possibility that the content of the strong layer transmission program and the content of the weak layer transmission program transmitted in the same physical channel are different. Therefore, as disclosed in Patent Documents 1 and 2, even if two channels are used to receive the same program on different channels, the contents of the weak-layer transmission program and the strong-layer transmission program in the channel If the content of the program is different, when the channel of the program being viewed by the user cannot be received by one system, the same program as that program cannot be received and displayed by the other system. There is a problem.

  Patent Documents 1 and 2 do not disclose reception of both a weak layer transmission program and a strong layer transmission program.

  The present invention shortens the time during which a user cannot view a program when the reception state changes due to movement or the like, and is weak in an area where a program of weak hierarchical transmission composed of high-quality video and audio can be received. An object of the present invention is to provide a digital broadcast receiving apparatus and a digital broadcast receiving method capable of viewing a hierarchical transmission program.

The digital broadcast receiving apparatus of the present invention receives a digital broadcast signal transmitted from a broadcast station, selects a channel, and weakens the video signal and audio signal of a relatively weak transmission program of the selected channel. A first system and a second system that output from the hierarchical video / audio decoding unit and output a video signal and audio signal of a relatively strong hierarchical transmission program from the strong hierarchical video / audio decoding unit; Any of the weak hierarchical video / audio decoding unit, the first system strong hierarchical video / audio decoding unit, the second system weak hierarchical video / audio decoding unit, and the second system strong hierarchical video / audio decoding unit A video / audio decoding unit selection unit for selecting and outputting a video signal and an audio signal output from the video signal, and displaying a video based on the video signal output from the video / audio decoding unit selection unit A video display unit, an audio output unit that outputs audio based on the audio signal output from the video / audio decoding unit selection unit, and a system that transmits a program of weak hierarchical transmission or strong hierarchical transmission of the selected channel. A reception failure detection unit that detects that reception is impossible, and a channel selection instruction to the first and second systems, and the video / audio decoding based on a detection result of the reception failure detection unit A channel selection control unit that controls the channel selection unit, and a program of weak hierarchical transmission of a channel selected by the first system, using program information included in the digital broadcast signal received by the first system And the content of the program of the strong hierarchical transmission is detected, and the program information included in the digital broadcast signal received by the second system is used to select the program of the second system. Weak hierarchy of channels And a program comparison unit and contents of the program content and strong hierarchical transmission of transmission of a program for detecting whether the same, the first system tunes a channel selected by the user The second system broadcasts a weak layer transmission program or a strong layer transmission program having the same content as at least one of a weak layer transmission program and a strong layer transmission program of a channel selected by the user. When the channel selection control unit determines that the first system is capable of receiving a weak layer transmission program, the first layer weak layer video / audio decoding unit is selected. The video / audio decoding unit selection unit is controlled to select and output the video signal and the audio signal output from the first system, the first system cannot receive a program of weak hierarchical transmission, and the first A program of strong hierarchical transmission by one system If it is determined that at least one of reception, reception of a weak layer transmission program by the second system, and reception of a strong layer transmission program by the second system is possible, The video / audio decoder selection unit is controlled to select and output any one of the video signal and the audio signal, and the first and second systems cannot simultaneously receive the digital broadcast signal. If it is determined, the video / audio decoding unit selection unit is controlled so as not to switch the video signal and audio signal to be output, and the program comparison unit performs a weak hierarchical transmission program of the channel selected in the first system by the program comparison unit. And the content of the strong layer transmission program are not the same, and the content of the weak layer transmission program of the channel selected by the second system is the same as the content of the strong layer transmission program. If at least one of them is detected, the video signal and audio signal of the program of weak hierarchical transmission of the channel selected in the system are detected with respect to the system in which the same is detected. Output from the weak layer video / audio decoding unit, and broadcast a strong layer transmission program with the same content as the weak layer transmission program of the channel selected by the system, and select another channel The channel selection instruction is performed so that the video signal and the audio signal of the program of the strong layer transmission of the further another channel are output from the strong layer video / audio decoding unit .

The digital broadcast receiving method of the present invention receives a digital broadcast signal transmitted from a broadcast station, selects a channel selected by a user, and a program with weakly weak layer transmission of the selected channel. A first reception step of outputting a video signal and an audio signal of the program, and a video signal and an audio signal of a relatively strong hierarchical transmission program, and a digital broadcast signal transmitted from the broadcast station, Select and select another channel that broadcasts a weak-layer transmission or a strong-layer transmission program with the same content as at least one of the selected channel's weak-layer transmission program and strong-layer transmission program. A video signal and an audio signal of a relatively weak layer transmission program of a station channel and a video signal and an audio signal of a relatively strong layer transmission program are output. Based on the detection results in the reception step, the reception failure detection step for detecting that the program of weak channel transmission or strong layer transmission of the selected channel cannot be received in each reception step, and the detection result in the reception failure detection step The video of any one of the weak layer transmission and the strong layer transmission program received in the first reception step and the weak layer transmission and the strong layer transmission program received in the second reception step. A video / audio selection step for selecting and outputting a signal and an audio signal, a video display step for displaying video based on the video signal output at the video / audio selection step, and an audio output at the video / audio selection step using a voice output step of outputting sound based on the signal, the program information included in the digital broadcast signal received by the first receiving step, The digital broadcast received in the second reception step is detected by detecting whether the content of the weak layer transmission program of the channel selected in the first reception step is the same as the content of the strong layer transmission program. Program comparison for detecting whether or not the content of the weak layer transmission program of the channel selected in the second reception step is the same as the content of the strong layer transmission program using the program information included in the signal In the first receiving step, the content of the weak layer transmission program of the channel selected in the first reception step is not the same as the content of the strong layer transmission program in the program comparison step. Is detected, a video signal and an audio signal of the weak channel transmission program of the selected channel are output, and a strong layer transmission of the same content as the weak layer transmission program of the selected channel is output. The other channel that is broadcasting the program is selected, and the video signal and the audio signal of the further hierarchical transmission program of the further channel are output. In the second receiving step, the program comparing step If it is detected that the contents of the weak channel transmission program of the channel selected in the second receiving step are not the same as the contents of the strong layer transmission program, the channel of the weak channel transmission of the selected channel is detected. The program outputs a video signal and an audio signal of the program, and broadcasts a program of strong hierarchical transmission having the same content as the program of weak hierarchical transmission of the selected channel. further outputs a video signal and an audio signal of the other channel of the strong hierarchical transmission of the program, in the video / audio selection step, the first in the receiving step can receive weak hierarchical transmission of the program If it is determined, the video signal and audio signal of weak hierarchy transmission output in the first reception step are selected and output, and the program of weak hierarchy transmission cannot be received in the first reception step. And receiving a program of strong layer transmission in the first receiving step, receiving a program of weak layer transmission in the second receiving step, and receiving a program of strong layer transmission in the second receiving step If it is determined that at least any one of them is possible, a video signal and an audio signal of any one of receivable programs are selected and output, and the first and second receiving steps are performed. At the same time, when it is determined that the digital broadcast signal cannot be received, the output video signal and audio signal are not switched.

  According to the digital broadcast receiver of the present invention, the channel selected by the user is selected by the first system, and is the same as at least one of the weak layer transmission program and the strong layer transmission program of the channel. Since the other channel that broadcasts the program of the weak layer transmission or the strong layer transmission of the content of the content is selected by the second system, it is possible to receive the same program by the first system and the second system It is. Thereby, even when the program of the channel selected by the first system cannot be received, the video signal and the audio signal of the same program can be output by the second system. When the first system can receive a program of weak hierarchy transmission, the video signal and audio signal output from the weak hierarchy video / audio decoding unit of the first system are selected by the video / audio decoding unit selection unit. The video is displayed by the video display unit based on the output video signal, and the audio is output by the audio output unit based on the output audio signal. Since a weak layer transmission program has a higher quality video signal and audio signal than a strong layer transmission program, the user can view the program with high quality video and audio.

  Further, when the first system cannot receive the program of the weak hierarchy transmission, the reception of the strong hierarchy transmission program by the first system, the reception of the weak hierarchy transmission program by the second system, and the second system If at least one of the receptions of the strong layer transmission program is possible, the video / audio decoding unit selection unit selects and outputs any one of the receivable programs. The video is displayed by the video display unit based on the output video signal, and the audio is output by the audio output unit based on the output audio signal. Since the first system and the second system can receive the same program, even if the first system cannot receive the program of weak hierarchical transmission, the video signal and the audio signal of the same program are It can be output by one system of strong hierarchical video / audio decoding section, second system of weak hierarchical video / audio decoding section, or second system of strong hierarchical video / audio decoding section. As a result, when the reception state changes due to movement or the like, the time during which the user cannot view the program can be shortened.

Therefore, compared with the prior art, it is possible to shorten the time during which the user cannot view the program and to provide the user with high-quality video and audio in an area where the program of weak hierarchical transmission can be received.
When the first and second systems cannot simultaneously receive a digital broadcast signal, the video / audio decoding unit selection unit is controlled by the channel selection control unit so that the video signal and audio signal to be output are not switched. . As a result, an undesired forward search can be suppressed. Therefore, when the first system and the second system can receive the digital broadcast signal again, they can be selected before the digital broadcast signal cannot be received. It is possible to immediately output the video and audio of the program of the channel that was being stationed. Therefore, it is possible to prevent the time during which the user cannot view the program from being lengthened by the forward search, and to shorten the time during which the user cannot view the program.

  According to the digital broadcast receiving method of the present invention, in the first receiving step, the digital broadcast signal transmitted from the broadcast station is received, the channel selected by the user is selected, and the selected channel is selected. A video signal and an audio signal of a relatively weak layer transmission program and a video signal and an audio signal of a relatively strong layer transmission program are output. In the second receiving step, the digital broadcast signal transmitted from the broadcast station is received, and the same content as at least one of the weak layer transmission program and the strong layer transmission program of the channel selected by the user Other channels that are broadcasting programs with weak or strong hierarchical transmission are selected, and the video and audio signals of relatively weak transmission programs of the selected channel and relatively strong strong are selected. The video signal and audio signal of the hierarchical transmission program are output.

  If it is determined in the first reception step that the program of weak layer transmission can be received, the video signal and audio signal of weak layer transmission output in the first reception step are selected and output. A video is displayed in the video display step based on the output video signal, and audio is output in the audio output step based on the output audio signal. Since a weak layer transmission program has a higher quality video signal and audio signal than a strong layer transmission program, the user can view the program with high quality video and audio.

  In addition, it is impossible to receive the program of the weak layer transmission in the first reception step, the reception of the program of the strong layer transmission in the first reception step, and the program of the weak layer transmission in the second reception step. If it is determined that at least one of reception and reception of a program of strong hierarchical transmission in the second reception step is possible, the video signal and audio signal of any one of the receivable programs Select to output. A video is displayed in the video display step based on the output video signal, and audio is output in the audio output step based on the output audio signal.

  Since the first reception step and the second reception step can receive the same program, the video signal and audio signal of the same program can be received even when the program of weak hierarchical transmission cannot be received in the first reception step. Can be output in the first reception step or the second reception step. As a result, when the reception state changes due to movement or the like, the time during which the user cannot view the program can be shortened.

Therefore, compared with the prior art, it is possible to shorten the time during which the user cannot view the program and to provide the user with high-quality video and audio in an area where the program of weak hierarchical transmission can be received.
If it is determined in the first and second reception steps that the digital broadcast signal cannot be received simultaneously , the video signal and audio signal to be output are not switched. As a result, an undesired forward search can be suppressed. Therefore, when the digital broadcast signal can be received again in the first and second reception steps, the channel is selected before the digital broadcast signal cannot be received. It is possible to immediately output the video and audio of the program of the channel that was being used. Therefore, it is possible to prevent the time during which the user cannot view the program from being lengthened by the forward search, and to shorten the time during which the user cannot view the program.

<First Embodiment>
FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus 1 according to the first embodiment of the present invention. The digital broadcast receiver 1 includes two reception systems that receive a digital broadcast signal, that is, a first system 200 and a second system 210. The digital broadcast receiver 1 includes a first antenna 2, a second antenna 3, a first tuner unit 201, a first demodulator 202, a first demultiplexer 203, Weak layer video / audio decoding unit 204, first strong layer video / audio decoding unit 205, second tuner unit 211, second demodulation unit 212, second demultiplexing unit 213, 2 weak layer video / audio decoding unit 214, second strong layer video / audio decoding unit 215, video / audio decoding unit selection unit 221, video display unit 222, audio output unit 223, and reception inability detection Unit 224, channel selection control unit 225, and channel storage unit 226.

  The first system 200 includes a first tuner unit 201, a first demodulation unit 202, a first demultiplexing unit 203, a first weak layer video / audio decoding unit 204, and a first strong layer video / audio. A decoding unit 205 is provided. The second system 210 includes a second tuner unit 211, a second demodulation unit 212, a second demultiplexing unit 213, a second weak layer video / audio decoding unit 214, and a second strong layer video / An audio decoding unit 215 is provided.

  A first antenna 2 capable of receiving a digital broadcast signal transmitted from a broadcasting station is connected to the first system 200, and a second antenna capable of receiving the digital broadcast signal is connected to a second system 210. 3 is connected. The digital broadcast signal received by the first antenna 2 is given to the first tuner unit 201 of the first system 200. The digital broadcast signal received by the second antenna 3 is given to the second tuner unit 211 of the second system 210.

  The first tuner unit 201 receives a digital broadcast signal given from the first antenna 2 and extracts a signal having a specific frequency from the received digital broadcast signal. Which frequency signal of the received digital broadcast signal is extracted by the first tuner unit 201 is controlled by a channel selection control unit 225 described later. In other words, the first tuner unit 201 extracts the signal having the specific frequency based on the predetermined control signal given from the channel selection control unit 225. The specific frequency is a frequency of any one of a plurality of channels included in the digital broadcast signal, and extracting the signal of the specific frequency means selecting a channel. The first tuner unit 201 outputs reception level information of the received signal.

  The first demodulator 202 demodulates the signal supplied from the first tuner unit 201 and corrects an error, and outputs a transport stream (abbreviation: TS). Further, the first demodulator 202 receives various information such as reception C / N ratio (Carrier to Noise ratio) information, PLL (Phase Locked Loop) lock information, frame lock information, and error rate information. Output at least one of them.

  The first demultiplexer 203 receives, for example, program specific information (Program Specific Information) from the received digital broadcast signal, specifically, TS given from the first demodulator 202, as program information that is information related to the program. (Abbreviation: PSI) and program arrangement information (service information: abbreviation: SI) are extracted, and the extracted PSI and SI are stored in a memory. The memory for storing the PSI and the SI may be, for example, a channel storage unit 226 described later or another storage unit.

  The first demultiplexing unit 203 uses the extracted PSI and / or SI (hereinafter also referred to as “PSI / SI”) to identify TS packet identifiers (Packet Identifiers) of video TS packets and audio TS packets in the TS. : PID) value is detected, and TS is filtered by each PID to separate and extract video TS packets and audio TS packets. The video TS packet and the audio TS packet include a video TS packet and an audio TS packet for weak layer transmission, and a video TS packet and an audio TS packet for strong layer transmission.

  Here, the strong hierarchy refers to a hierarchy having a relatively strong resistance to the C / N ratio among a plurality of hierarchies configured by dividing the transmission band in the hierarchical transmission scheme. In strong hierarchical transmission, a modulation scheme that is strong against reception by a mobile unit is performed, and stable reception is possible up to a low reception level. However, since the amount of data is small, a low-quality service is provided. In other words, the signal of the strong layer transmission is inferior in image quality, but has high tolerance to the C / N ratio and can be received even at a low C / N ratio. The weak hierarchy refers to a hierarchy that is relatively weak in resistance to the C / N ratio among a plurality of hierarchies configured by dividing the transmission band in the hierarchical transmission scheme. In weak hierarchical transmission, a modulation scheme with high transmission efficiency is performed to transmit a large amount of data, and high-quality service is possible, but it is weak for reception at a mobile unit and reception at a low reception level. Has characteristics. In other words, the weak layer transmission signal includes high-quality video, but has low resistance to the C / N ratio.

  The first demultiplexing unit 203 gives the video TS packet and the audio TS packet for weak layer transmission to the first weak layer video / audio decoding unit 204, and the video TS packet and the audio TS packet for strong layer transmission are the first. To the strong hierarchical video / audio decoding unit 205.

  The first demultiplexing unit 203 includes a program association table (abbreviation: PAT) disconnection information (disruption information), a program correspondence table (program map table; abbreviation: PMT) disconnection information (disruption information). At least one of TS out-of-synchronization (synchronous lost) information and various types of information on TS packet loss information (packet lost information) is output.

  The PAT disconnection information is issued when the PAT does not arrive at a predetermined time interval. The PMT disconnection information is issued when the PMT does not arrive at a predetermined time interval. TS synchronization loss information (notification) is issued when a synchronization byte is not detected every 188 bytes in the TS. The TS packet loss information (notification) is issued when a discontinuity of the continuity counter value existing in the TS header is detected.

  Note that a TS may include a plurality of weak hierarchical services and a plurality of strong hierarchical services. Which service of the services included in the TS is selected by the first demultiplexing unit 203 is controlled by the channel selection control unit 225 described later. In other words, the first demultiplexing unit 203 selects a service included in the TS based on the predetermined control signal given from the channel selection control unit 225.

  The first weak layer video / audio decoding unit 204 decodes the video TS packet and audio TS packet of the weak layer transmission given from the first demultiplex unit 203, and the decoded video signal and audio of the video packet are decoded. The audio signal obtained by decoding the packet is supplied to the video / audio decoding unit selection unit 221. In addition, the first weak layer video / audio decoding unit 204 is in a state in which at least one of the decoding of the video TS packet for weak layer transmission and the decoding of the audio TS packet for weak layer transmission cannot be performed. At least one of decoding error detection information and decoding error rate information is output.

  The first strong layer video / audio decoding unit 205 decodes the video TS packet and audio TS packet of the strong layer transmission given from the first demultiplexing unit 203, and the decoded video signal and audio of the video packet. The audio signal obtained by decoding the packet is supplied to the video / audio decoding unit selection unit 221. In addition, the first strong layer video / audio decoding unit 205 is in a state in which at least one of decoding of the strong layer transmission video TS packet and strong layer transmission audio TS packet cannot be processed. At least one of decoding error detection information and decoding error rate information is output.

  Second tuner unit 211, second demodulating unit 212, second demultiplexing unit 213, second weak layer video / audio decoding unit 214, and second strong layer video configuring second system 210 / Audio decoding unit 215 includes a first tuner unit 201, a first demodulation unit 202, a first demultiplexing unit 203, a first weak layer video / audio decoding unit 204, which constitute the first system 200, And the first strong layer video / audio decoding unit 205 having the same functions and performing the same operation, the second tuner unit 211, the second demodulation unit 212, the second demultiplexing unit 213, The description of the second weak layer video / audio decoding unit 214 and the second strong layer video / audio decoding unit 215 is omitted.

  The video / audio decoding unit selection unit 221 includes a video signal and an audio signal supplied from the first weak layer video / audio decoding unit 204, and a video signal and an audio signal supplied from the first strong layer video / audio decoding unit 205. Any one of the video signal and audio signal provided from the second weak layer video / audio decoding unit 214 and the video signal and audio signal provided from the second strong layer video / audio decoding unit 215. The selected video signal is supplied to the video display unit 222, and the selected audio signal is supplied to the audio output unit 223.

  The video / audio decoding unit selection unit 221 receives the video signal and audio from the first and second weak hierarchical video / audio decoding units 204 and 214 and the first and second strong hierarchical video / audio decoding units 205 and 215. Which video signal and audio signal are selected from the signals is controlled by the channel selection control unit 225. In other words, the video / audio decoding unit selection unit 221 selects a video signal and an audio signal based on a predetermined control signal given from the channel selection control unit 225.

  The video display unit 222 displays video on the display screen based on the video signal given from the video / audio decoding unit selection unit 221. The audio output unit 223 outputs audio from the speaker based on the audio signal provided from the video / audio decoding unit selection unit 221.

  In a digital broadcast receiving device mounted on or carried by a mobile object such as a vehicle, the receiving position of the digital broadcast receiving device moves, so that the receiving position is outside the service area of the broadcasting station of the program being viewed, or on the ground In such a case, it is impossible to receive a broadcast signal from a broadcasting station that broadcasts the program being viewed. As described above, the unreceivable detection unit 224 detects a state where it is impossible to receive a broadcast signal from a broadcast station (hereinafter sometimes referred to as a “reception unreachable state”).

  The unreceivable detection unit 224 includes the various information output from the first tuner unit 201, the first demodulation unit 202, the first demultiplexing unit 203, and the first weak layer video / audio decoding unit 204. Based on at least one of them, it is detected that the received signal of the weak layer of the first system 200 is in a “reception impossible state”.

  For example, if the reception level represented by the reception level information is less than a predetermined value based on the reception level information given from the first tuner unit 201, the reception failure detection unit 224 cannot receive the reception signal of the weak layer. Judge that there is.

  The reception failure detection unit 224 is weak when the C / N ratio represented by the reception C / N ratio information is less than a predetermined value based on the reception C / N ratio information given from the first demodulation unit 202, for example. It is determined that the reception signal of the hierarchy cannot be received. Further, for example, when it is determined that the PLL lock has been released based on the PLL lock information provided from the first demodulating unit 202, the reception impossibility detecting unit 224 determines that the received signal of the weak layer cannot be received. . Further, for example, when it is determined that the frame lock has been released based on the frame lock information provided from the first demodulator 202, the reception impossibility detection unit 224 determines that the reception signal of the weak layer is not receivable. . Further, for example, when it is determined that the error rate exceeds a predetermined value based on the error rate information given from the first demodulating unit 202, the reception failure detection unit 224 cannot receive the reception signal of the weak layer. Judge.

  For example, based on the PAT disconnection information provided from the first demultiplexing unit 203, the reception impossibility detection unit 224 determines that the reception signal of the weak hierarchy is not receivable when the PAT disconnection is detected. Further, for example, based on the PMT disconnection information provided from the first demultiplexing unit 203, the reception impossibility detection unit 224 determines that the reception signal of the weak layer is not receivable when the PMT disconnection is detected. Further, for example, the reception failure detection unit 224 indicates that the reception signal of the weak layer cannot be received when the TS synchronization loss is detected based on the TS synchronization loss information given from the first demultiplexing unit 203. to decide. Further, the reception failure detection unit 224 determines that the reception signal of the weak layer cannot be received when the loss of the TS packet is detected based on the loss information of the TS packet given from the first demultiplexing unit 203. to decide.

  For example, when the decoding error is detected based on the decoding error detection information given from the first weak hierarchy video / audio decoding unit 204, the reception impossible detection unit 224 cannot receive the reception signal of the weak hierarchy. Judge. Further, for example, when the decoding error rate is determined to exceed the predetermined value based on the decoding error rate information given from the first weak layer video / audio decoding unit 204, the reception failure detection unit 224 It is determined that the received signal cannot be received.

  The unreceivable detection unit 224 receives the various information output from the first tuner unit 201, the first demodulation unit 202, the first demultiplexing unit 203, and the first strong layer video / audio decoding unit 205. Based on at least one of them, it is detected that the received signal in the higher hierarchy of the first system 200 is in a “reception impossible state”.

  The non-reception detection unit 224 receives the various information output from the second tuner unit 211, the second demodulation unit 212, the second demultiplexing unit 213, and the second weak layer video / audio decoding unit 214. Based on at least one of them, it is detected that the received signal in the weak layer of the second system 210 is in a “reception impossible state”.

  The reception failure detection unit 224 includes the various information output from the second tuner unit 211, the second demodulation unit 212, the second demultiplexing unit 213, and the second strong layer video / audio decoding unit 215. Based on at least one of them, it is detected that the received signal in the strong hierarchy of the second system 210 is in a “reception impossible state”.

  Further, the reception failure detection unit 224 receives “reception signals” in the weak hierarchy of the first system 200, the strong hierarchy of the first system 200, the weak hierarchy of the second system 210, and the strong hierarchy of the second system 210. When it is determined that the state is “impossible state”, a reception impossible notification is given to the channel selection control unit 225.

  The channel selection control unit 225 controls the first tuner unit 201 and the first demultiplexing unit 203 based on the channel selection request from the user and the reception disabled notification from the reception disabled detection unit 224. Which channel is selected in the first system 200 is determined. The channel selection control unit 225 controls the second tuner unit 211 and the second demultiplexing unit 213 based on the channel selection request from the user and the reception failure notification from the reception failure detection unit 224. The second system 210 determines which channel to select.

  The channel storage unit 226 sequentially selects all the channels of the broadcast station, detects channels that can be received at the reception position of the digital broadcast receiver, and stores channel information of receivable broadcast stations acquired by so-called channel scan. To do. The channel storage unit 226 may store information indicating whether or not the stored broadcast stations are affiliated with each other. Here, the affiliated station is a broadcast station having the same field value of affiliated carrier identification (affiliation_id) in the Broadcaster Information Table (abbreviation: BIT) section of the program arrangement information (SI) in the TS. is there. The BIT has a function of designating a broadcaster unit and SI transmission parameters for each broadcaster unit. The channel storage unit 226 may store physical channel information of a multi-frequency network (abbreviation: MFN) instead of information for indicating the relationship between affiliated stations. The channel storage unit 226 may store both affiliated station information and MFN information.

  FIG. 2 is a flowchart showing a processing procedure of the operation of the channel selection control unit 225 of the digital broadcast receiving device 1 according to the first embodiment of the present invention. The digital broadcast receiving method will also be described with reference to FIG. 2 and FIG. 3 described later. The processing of the channel selection control unit 225 in the flowchart shown in FIG. 2 is repeatedly executed when power is supplied to the digital broadcast receiving apparatus 1 and the start condition is satisfied. Here, it is assumed that the user selects the first broadcasting station A and receives the first broadcasting station A by the first system 200. Also, the first weak layer video / audio decoding unit 204 decodes the video TS packet and the audio TS packet of the weak layer transmission program of the first broadcasting station A, and the first strong layer video / audio decoding unit 205 The video TS packet and the audio TS packet of the program of strong hierarchical transmission of the first broadcasting station A are decoded, and the video signal given from the first weak hierarchical video / audio decoding unit 204 by the video / audio decoding unit selection unit 221 It is assumed that the audio signal or the video signal and audio signal given from the first strong layer video / audio decoding unit 205 are selected. The step of receiving the first broadcasting station A by the first system 200 corresponds to the first receiving step. At this time, the channel selection control unit 225 operates using the second system 210 according to the flowchart shown in FIG. The operation of the second system 210 according to the flowchart shown in FIG. 2 corresponds to the second reception step.

  In the flowchart shown in FIG. 2, when the broadcast station received by the first system 200 changes due to a channel selection request from the user, or when the reception state of the channel received by the second system 210 deteriorates. This process is started, and the process proceeds to step a1.

  In step a1, it is determined whether or not the channel storage unit 226 stores a broadcast station of the same series as the first broadcast station A, that is, an affiliated station. In step a1, if an affiliated station is stored, the process proceeds to step a2, and if an affiliated station is not stored, all processing procedures are terminated.

  In step a2, the channel having the smallest channel number among the affiliated stations of the first broadcasting station A stored in the channel storage unit 226 is selected by the second system 210, and the process proceeds to step a3. Here, the channel selected by the second system 210 is at least one of a weak layer transmission program and a strong layer transmission program of the channel of the first broadcasting station A which is a channel selected by the user. This corresponds to another channel broadcasting a program of weak layer transmission or strong layer transmission of the same content. In the present embodiment, the channel selected in the first and second systems 200 and 210 has the same contents of the weak layer transmission program and the strong layer transmission program. Therefore, the contents of the weak-layer transmission program of the channel selected by the second system 210 are the contents of the strong-layer transmission program of the channel and the weak hierarchy transmission of the channel selected by the first system 200. And the content of the program of strong hierarchical transmission.

  In step a3, the reception status output from the second system 210 is acquired, and the acquired reception status is stored in the channel storage unit 226 or another storage unit. Here, the reception status information stored in the channel storage unit 226 or another storage unit includes the reception level information output from the second tuner unit 211 and the reception C / N ratio output from the second demodulation unit 212. Information, PLL lock information, frame lock information and error rate information, PAT disconnection information, PMT disconnection information, TS synchronization loss information and TS packet loss information output from the second demultiplexing unit 213, Of the decoding error detection information and decoding error rate information output from the weak layer video / audio decoding unit 214 and the decoding error detection information and decoding error rate information output from the second strong layer video / audio decoding unit 215 , At least one of them is included. In step a3, when the reception status is stored in the channel storage unit 226 or another storage unit, the process proceeds to step a4.

  In step a4, it is determined whether or not the channel selected by the second system 210 is the channel having the maximum channel number among the affiliated stations of the first broadcasting station A stored in the channel storage unit 226. To do. In step a4, if the channel selected by the second system 210 is the channel having the maximum channel number among the affiliated stations, the process proceeds to step a6, and the channel is selected by the second system 210. If the channel is not the channel with the maximum channel number in the affiliated station, the process proceeds to step a5.

  In step a5, the next affiliated station is selected, and the process returns to step a3. In step a6, the priority of the affiliated station of the first broadcast station A is calculated based on the reception status stored in the channel storage unit 226 or another storage unit and stored in the channel storage unit 226. For example, the priority is set higher as the reception level is higher. When the priority of the affiliated station is calculated and stored in the channel storage unit 226 in step a6, the process proceeds to step a7.

  In step a7, the broadcasting station with the highest priority is selected from the affiliated stations of the first broadcasting station A, the selected broadcasting station is selected by the second system 210, and the process proceeds to step a8. In step a8, the reception status output from the second system 210 is acquired, and it is determined whether or not the reception status of the second system 210 is good. If it is determined in step a8 that the reception state is good, all processing procedures are terminated, and if it is determined that the reception state is not good, the process returns to step a2.

  In the flowchart of FIG. 2, the channel to be selected by the second system 210 may be the MFN channel of the first broadcasting station A. The target to be selected by the second system 210 may be both the affiliated station of the first broadcasting station A and the MFN. When both the affiliated station and the MFN are to be selected, the priority of either the affiliated station or the MFN may be set high for the calculation of the priority in step a6 in FIG. May be handled.

  FIG. 3 is a flowchart showing a processing procedure of the operation of the channel selection control unit 225 of the digital broadcast receiving device 1 according to the first embodiment of the present invention. The process of the channel selection control unit 225 in the flowchart shown in FIG. 3 is repeatedly executed when power is supplied to the digital broadcast receiving apparatus 1 and the start condition is satisfied. In the flowchart shown in FIG. 3, this processing is started when the reception state of the first system 200 changes, or when the first system 200 is incapable of receiving and the reception state of the second system 210 changes. Then, the process proceeds to step b1.

  In step b1, the reception status of the first system 200, specifically, whether or not the first system 200 can receive a broadcast signal of weak layer transmission, that is, whether or not the program of weak layer transmission can be received. Judge whether or not. In step b1, if the first system 200 can receive the program of weak layer transmission, the process proceeds to step b2. If the first system 200 cannot receive the program of weak layer transmission, the process proceeds to step b3. .

  In step b2, the video / audio decoding unit selection unit 221 is controlled so that the video based on the video signal of the weak layer transmission received by the first system 200 is output by the video display unit 222, and the audio signal of the weak layer transmission is output. The sound output unit 223 outputs sound based on the above. After the processing in step b2, all processing procedures are terminated.

  In step b3, whether or not the first system 200 cannot receive the broadcast signal of the weak hierarchy transmission and can receive the broadcast signal of the strong hierarchy transmission, that is, the program of the weak hierarchy transmission in the first system 200 is received. It is determined whether or not it is possible to receive a program that cannot be received and that is transmitted through a strong hierarchy. In step b3, if the first system 200 cannot receive the weak layer transmission program and can receive the strong layer transmission program, the process proceeds to step b4. If both strong layer transmission programs cannot be received, the process proceeds to step b5.

  In step b4, the video / audio decoding unit selection unit 221 is controlled so that the video display unit 222 outputs video based on the strong hierarchical transmission video signal received by the first system 200, and the strong hierarchical transmission audio signal is output. The sound output unit 223 outputs sound based on the above. Specifically, the channel selection control unit 225 changes the video / audio decoding unit that outputs the video signal and the audio signal from the first weak hierarchical video / audio decoding unit 204 to the first strong hierarchical video / audio decoding unit 205. The video / audio decoding unit selection unit 221 is controlled so as to switch, that is, the video signal and audio signal to be output are switched, and the strong hierarchical transmission output from the first strong hierarchical video / audio decoding unit 205 is controlled. The video signal and the audio signal are output from the video / audio decoding unit selection unit 221. After the processing of step b4, all processing procedures are terminated.

  In step b5, the reception status of the second system 210, specifically, whether or not the second system 210 can receive the broadcast signal of the weak layer transmission, that is, the program of the weak layer transmission can be received. Judge whether or not. In step b5, if the second system 210 can receive the program of weak layer transmission, the process proceeds to step b6. If the second system 210 cannot receive the program of weak layer transmission, the process proceeds to step b8. .

  In step b6, the video / audio decoding unit selection unit 221 is controlled to output a video based on the video signal of the weak layer transmission received by the second system 210 by the video display unit 222, and the audio signal of the weak layer transmission is output. The sound output unit 223 outputs sound based on the above. Specifically, the channel selection control unit 225 changes the video / audio decoding unit that outputs the video signal and the audio signal from the first weak hierarchical video / audio decoding unit 204 to the second weak hierarchical video / audio decoding unit 214. The video / audio decoding unit selection unit 221 is controlled to switch the video signal and audio signal of the strong layer transmission output from the second weak layer video / audio decoding unit 214 to the video / audio decoding unit selection unit 221. Output from. After step b6, the process proceeds to step b7.

  In step b7, the roles of the first system 200 and the second system 210 are switched. That is, after step b7, the program for viewing by the user is received by the second system 210, and the first system 200 operates according to the flowchart of FIG. After the processing of step b7, all processing procedures are terminated.

  In step b8, whether or not the second system 210 cannot receive the broadcast signal of the weak layer transmission and can receive the broadcast signal of the strong layer transmission, that is, the program of the weak layer transmission in the second system 210 is received. It is determined whether or not it is possible to receive a program that cannot be received and that is transmitted through a strong hierarchy. In step b8, if the second system 210 cannot receive the weak layer transmission program and can receive the strong layer transmission program, the process proceeds to step b9. If both strong layer transmission programs cannot be received, the process proceeds to step b10.

  In step b9, the video / audio decoding unit selection unit 221 is controlled so that the video display unit 222 outputs a video based on the video signal of the strong hierarchical transmission received by the second system 210, and the audio signal of the strong hierarchical transmission is output. The sound output unit 223 outputs sound based on the above. Specifically, the channel selection control unit 225 changes the video / audio decoding unit that outputs the video signal and the audio signal from the first weak hierarchical video / audio decoding unit 204 to the second strong hierarchical video / audio decoding unit 215. The video / audio decoding unit selection unit 221 is controlled so as to switch the video signal and audio signal of the strong layer transmission output from the second strong layer video / audio decoding unit 215 to the video / audio decoding unit selection unit 221. Output from. After the process of step b9, the process proceeds to step b7.

  In step b10, a program having the same content as that of the first broadcasting station A in order from the smallest physical channel in which digital broadcasting is operated, more specifically, a program of weak hierarchical transmission of a channel corresponding to the first broadcasting station A. A search is made for another channel that broadcasts a program of weak hierarchical transmission with the same content as (hereinafter also referred to as “forward search”). If a channel that broadcasts a program having the same content is found by the forward search, the channel is selected. In step b10, if a channel broadcasting a program with the same content is not found, the forward search is continued until it is found. After the processing of step b10, all processing procedures are terminated. In step b10, as described above, the forward search may be continued until a channel broadcasting a program having the same content is found, or the forward search is continued until a predetermined time elapses. You may make it complete | finish all the process procedures after progress.

  In the flowchart of FIG. 3, Step b1, Step b3, Step b5 and Step b8 correspond to a reception failure detection step, and Step b2, Step b4, Step b6 and Step b9 are a video / audio selection step and a video display step. This corresponds to the voice output step.

  In the flowchart of FIG. 3, when both the weak layer transmission program and the strong layer transmission program cannot be received in the second system 210 in step b8, the process proceeds to step b10. If neither channel is selected or if the second system 210 is operating according to the flowchart shown in FIG. 2, the process proceeds to step b10.

  FIG. 4 is a diagram showing areas in which broadcast signals transmitted from the first broadcast station A and the second broadcast station B can be received. The first broadcasting station A is a broadcasting station that performs broadcasting on a channel selected by the user and selected by the first system 200. The second broadcasting station B is a broadcasting station that performs broadcasting on a channel selected by the second system 210. The second broadcasting station B is an affiliated station of the first broadcasting station A, and broadcasts programs having the same content (hereinafter sometimes referred to as “same programs”). In the present embodiment, the first broadcast station A and the first broadcast station A on which the same program is broadcasted when the moving body moves at the six points shown in FIG. 4, specifically, the first to sixth points 105 to 110. Consider a case where a broadcast signal transmitted from at least one of two broadcast stations B is received. The first to sixth points 105 to 110 are on a straight line, and a predetermined interval is provided between the points.

  The first point 105 may be an area where the broadcast signal of the weak hierarchy transmission of the first broadcast station A, that is, the area where the program of the weak hierarchy transmission of the first broadcast station A can be received (hereinafter referred to as “first weak hierarchy reception area”). ) 101 and a region included in a region 102 (hereinafter also referred to as “first strong layer reception region”) capable of receiving a program of strong layer transmission of the first broadcasting station A. The second point 106 is a point included in the first strong layer reception area 102. The third point 107 is an area in which the first strong layer reception area 102 and the broadcast signal of the strong broadcast transmission of the second broadcasting station B, that is, the strong broadcast transmission program of the second broadcast station B (hereinafter referred to as “second”). It is a point included in 104). The fourth point 108 is a point included in the second strong layer reception area 104. The fifth and sixth points 109 and 110 are areas that can receive the broadcast signal of the weak layer transmission of the second broadcasting station B, that is, the program of the weak layer transmission of the second broadcast station B (hereinafter referred to as “second weak layer reception area” ”And the second strongest layer reception area 104.

  At the time when the mobile body departs from the first point 105, the digital broadcast receiving apparatus 1 receives the weak layer transmission program and the strong layer transmission program of the first broadcast station A by the first system 200, and the video / audio is received. The decoding unit selection unit 221 selects the video signal and audio signal of the weak hierarchical transmission of the first broadcasting station A received by the first system 200. Next, when the moving body moves from the first point 105 to the second point 106, the digital broadcast receiving apparatus 1 uses the video / audio decoding unit selection unit 221 to perform the video signal and audio signal for the strong hierarchical transmission of the first broadcasting station A. Select.

  Next, when the moving body moves from the second point 106 to the third point 107, the digital broadcast receiving apparatus 1 receives the program of the strong hierarchical transmission of the second broadcast station B by the second system 210. Next, when the moving body moves from the third point 107 to the fourth point 108, the digital broadcast receiving apparatus 1 uses the video / audio decoding unit selection unit 221 to transmit the video signal and audio signal of the second broadcast station B for strong hierarchical transmission. select.

  When the moving body moves from the fourth point 108 to the fifth point 109, the digital broadcast receiving apparatus 1 receives the program of weak hierarchical transmission of the second broadcast station B by the second system 210, and performs video / audio decoding. The video signal and audio signal of weak hierarchical transmission of the second broadcasting station B are selected by the part selector 221. Even when the moving body moves from the fifth point 109 to the sixth point 110, the digital broadcast receiving apparatus 1 uses the video / audio decoding unit selection unit 221 to weaken the second broadcast station B, as with the fifth point 109. Select video and audio signals for transmission.

  As described above, the digital broadcast receiving apparatus 1 according to the present embodiment selects the channel selected by the user using the first system 200, and sets the other channel that broadcasts the same program as that channel to the second channel. Therefore, the same program can be received by the first system 200 and the second system 210. As a result, even when the program of the channel selected by the first system 200 cannot be received, the video signal and audio signal of the same program can be output by the second system 210. Therefore, if the receivable area of the channel selected by the first system 200 and the receivable area of the channel selected by the second system 210 overlap, the video signal and the audio signal are not interrupted. Can be output.

  For example, in the present embodiment, two strong layer transmission programs can be received simultaneously by the first and second systems 200 and 210. Therefore, as shown in FIG. If the strong reception area 104 overlaps, the video signal and the audio signal can be output without being interrupted.

  In the present embodiment, when the first system 200 can receive a program of weak hierarchical transmission, the video signal and audio signal output from the weak hierarchical video / audio decoding unit 204 of the first system 200 are video. The video display unit 222 displays video based on the video signal selected and output by the audio decoding unit selection unit 221, and the audio output unit 223 outputs audio based on the output audio signal. . Since a weak layer transmission program has a higher quality video signal and audio signal than a strong layer transmission program, the user can view the program with high quality video and audio.

  As described above, the digital broadcast receiving apparatus 1 according to the present embodiment switches to receiving a weak layer transmission program when a weak layer transmission program can be received. Can be presented.

  When the first system 200 is unable to receive a program of weak layer transmission, the first system 200 receives a weak layer transmission program, the second system 210 receives a weak layer transmission program, and the second system If at least one of the strong hierarchical transmission programs received by the system 210 can be received, any one video signal and audio signal of the receivable programs is converted into the video / audio decoding unit selection unit 221. A video is displayed by the video display unit 222 based on the video signal selected and output by the video output unit, and audio is output by the audio output unit 223 based on the output audio signal. Specifically, the video / audio decoding unit selection unit 221 switches the video / audio decoding unit that outputs the video signal and the audio signal to the video / audio decoding unit that can receive the video signal and the audio signal. Then, the channel selection control unit 225 controls the video signal and audio signal to be output so as to switch to the video signal and audio signal of the receivable program.

  Since the first system 200 and the second system 210 can receive the same program, the video signal and audio signal of the same program can be received even when the first system 200 cannot receive the weak hierarchical transmission program. Is output by the strong hierarchical video / audio decoding unit 205 of the first system 200, the weak hierarchical video / audio decoding unit 214 of the second system 210, or the strong hierarchical video / audio decoding unit 215 of the second system 210. be able to. As a result, when the reception state changes due to movement or the like, the time during which the user cannot view the program can be shortened.

  Therefore, compared with the prior art, it is possible to shorten the time during which the user cannot view the program and to provide the user with high-quality video and audio in an area where the program of weak hierarchical transmission can be received.

<Second Embodiment>
Next, a digital broadcast receiving apparatus according to the second embodiment of the present invention will be described. Since the configuration of the digital broadcast receiving apparatus of the present embodiment is the same as that of the digital broadcast receiving apparatus 1 of the first embodiment described above, the same reference numerals are assigned to corresponding portions, and the first embodiment The description common to the embodiment is omitted. Also in the present embodiment, the contents of the weak-layer transmission program of the channel selected by the first system 200 are the same as the content of the strong-layer transmission program, and are selected by the second system 210. The contents of the program of the weak layer transmission of the channel and the content of the program of the strong layer transmission are the same.

  FIG. 5 is a diagram illustrating areas in which broadcast signals transmitted from the first broadcast station A and the second broadcast station B can be received. In the present embodiment, when the moving body moves at the three points shown in FIG. 5, specifically, the first to third points 115 to 117, the first broadcast station A and the first broadcast station A that are broadcasting the same program. Consider a case where a broadcast signal transmitted from at least one of two broadcast stations B is received. The first to third points 115 to 117 are on a straight line, and a predetermined interval is provided between the points.

  The first point 115 may be referred to as an area where the broadcast signal of the weak hierarchy transmission of the first broadcasting station A, that is, the area where the program of the weak hierarchy transmission of the first broadcast station A can be received (hereinafter referred to as “first weak hierarchy reception area”). ) 111 and an area where the broadcast signal of the strong broadcast transmission of the first broadcast station A, that is, the program of the strong broadcast transmission of the first broadcast station A can be received (hereinafter also referred to as “first strong hierarchy reception area”) 112. It is a point included in. The second point 116 is an area where the first strong layer reception area 112 and the broadcast signal of the second broadcast station B weakly transmitted, that is, the area where the second broadcast station B weakly transmitted program can be received (hereinafter referred to as “second weakly second”). 113, and a broadcast signal of strong broadcast transmission of the second broadcast station B, that is, an area in which a program of strong broadcast transmission of the second broadcast station B can be received (hereinafter referred to as “second strong hierarchy reception”). It may be referred to as “region”). The third point 117 is a point included in the second weak layer reception area 113 and the second strong layer reception area 114.

  In the first embodiment described above, when the moving body moves from the first point 115 to the second point 116, the digital broadcast receiving device 1 can receive the program of the strong hierarchical transmission of the first broadcasting station A. The second broadcast station B is not configured to receive a weak layer transmission program and switch from a strong layer transmission program to a weak layer transmission program. For this reason, even in areas where weak layer transmission programs can be received, strong layer transmission programs may be received and strong layer transmission programs composed of low-quality video and audio may be presented to the user.

  FIG. 6 is a flowchart showing a processing procedure of the operation of the channel selection control unit 225 of the digital broadcast receiving apparatus according to the second embodiment of the present invention. The process of the channel selection control unit 225 in the flowchart shown in FIG. 6 is repeatedly executed when power is supplied to the digital broadcast receiving apparatus and the start condition is satisfied. In the flowchart shown in FIG. 6, this process is started when the reception state of the first system 200 or the second system 210 changes, and the process proceeds to step c1. The operation of the channel selection control unit 225 in FIG. 6 is similar to the operation of the channel selection control unit 225 in FIG. 3 described above. Therefore, only the parts that are different in control operation will be described in detail, and the channel selection control unit 225 in FIG. As for the same parts as the operation of, overlapping explanation is omitted.

  Since the processing of step c1 and step c2 is the same as the processing of step b1 and step b2 of FIG. 3, the description of each processing of steps c1 and c2 is omitted. After the processing of step c2, all processing procedures are terminated. In step c1, if the first system 200 cannot receive the program of the weak hierarchical transmission, the process proceeds to step c3.

  In step c3, whether or not the first system 200 cannot receive the broadcast signal of the weak hierarchy transmission and can receive the broadcast signal of the strong hierarchy transmission, that is, the program of the weak hierarchy transmission in the first system 200 is received. It is determined whether or not it is possible to receive a program that cannot be received and that is transmitted through a strong hierarchy. In step c3, if the first system 200 cannot receive the weak layer transmission program and the strong layer transmission program can be received, the process proceeds to step c4, and the first system 200 performs the weak layer transmission program and If both strong layer transmission programs cannot be received, the process proceeds to step c8.

  In step c4, the reception status of the second system 210, specifically, whether or not the second system 210 can receive the broadcast signal of the weak layer transmission, that is, the program of the weak layer transmission in the second system 210. It is determined whether or not can be received. In step c4, if the second system 210 can receive a program of weak layer transmission, the process proceeds to step c5. If the second system 210 cannot receive a program of weak layer transmission, the process proceeds to step c7. .

  Since the processes at steps c5, c6, and c7 are the same as the processes at steps b6, b7, and b4 in FIG. 3, the description of the processes at steps c5, c6, and c7 is omitted. After the completion of the processes in step c6 and step c7, all processing procedures are terminated.

  Further, the processes of step c8 to step c13 are the same as the processes of step b5 to step b10 of FIG. 3 described above, so the description of each process of step c8 to step c13 is omitted. After completion of the processes of step c10, step c12, and step c13, all processing procedures are terminated.

  In the flowchart of FIG. 6, step c1, step c3, step c4, step c8 and step c11 correspond to a reception failure detection step, and step c2, step c5, step c7, step c9 and step c12 are video / audio. This corresponds to a selection step, a video display step, and an audio output step.

  As described above, in the digital broadcast receiving apparatus according to the present embodiment, the channel selection control unit 225 cannot receive the program whose first system 200 is weakly transmitted and the second system 210 is weakly transmitted. Video / audio decoding unit selection unit 221 so as to select and output the video signal and audio signal output from weak layer video / audio decoding unit 214 of second system 210. To control. In other words, the channel selection control unit 225, when the first system 200 cannot receive the weak layer transmission program, even if the first system 200 can receive the strong layer transmission program, If it is possible to receive a program of weak layer transmission in 210, the video / audio decoding unit selection unit 221 is controlled so that the video / audio decoding unit that outputs the video signal and the audio signal is used as the first weak layer video / audio. Switching from the decoding unit 204 to the second weak layer video / audio decoding unit 214, and the video of the weak layer transmission program received by the second system 210 from the weak layer video / audio decoding unit 214 of the second system 210 Output signals and audio signals.

  Therefore, when the moving body moves from the first point 115 to the third point 117 shown in FIG. 5, when the moving body moves from the first point 115 to the second point 116, the video / audio decoding unit selection unit 221 performs the second operation. A video signal and an audio signal of weak hierarchy transmission of the broadcasting station B are selected. As described above, in the digital broadcast receiving apparatus of the present embodiment, even when the first system 200 can receive the program of the strong hierarchical transmission of the first broadcast station A, the second broadcast station B can be used with the second system 210. If it is possible to receive the weak layer transmission program of the second broadcast station B, the weak layer transmission program of the second broadcasting station B is received and switched from the strong layer transmission program to the weak layer transmission program.

  Therefore, in the present embodiment, the possibility of outputting high-quality video and audio is higher than in the digital broadcast receiving apparatus 1 of the first embodiment described above. In other words, it is possible to increase the possibility that a user can view a program in a weak hierarchy composed of high-quality video and audio.

<Third Embodiment>
Next, a digital broadcast receiver according to a third embodiment of the present invention will be described. Since the configuration of the digital broadcast receiving apparatus of the present embodiment is the same as that of the digital broadcast receiving apparatus 1 of the first embodiment described above, the same reference numerals are assigned to corresponding portions, and the first embodiment The description common to the embodiment is omitted. Also in the present embodiment, the contents of the weak-layer transmission program of the channel selected by the first system 200 are the same as the content of the strong-layer transmission program, and are selected by the second system 210. The contents of the program of the weak layer transmission of the channel and the content of the program of the strong layer transmission are the same.

  In the above-described second embodiment, when a mobile body equipped with a digital broadcast receiving device is located in an area where no digital broadcast signal can be received, for example, in a tunnel, the operation according to the flowchart shown in FIG. 6 is performed. . Specifically, the first system 200 and the second system 210 cannot receive both the weak layer transmission program and the strong layer transmission program, and a forward search is performed in step c13 in FIG. However, since the mobile body is located in an area where digital broadcasting cannot be received at all, the user cannot view the program of the first broadcasting station A that has been viewed. Even if the user exits from an area such as a tunnel that cannot receive any digital broadcast signal during the forward search in step c13, the program remains interrupted unless the channel of the first broadcast station A is selected. Therefore, performing the forward search in step c13 may increase the time during which the program is interrupted.

  FIG. 7 is a flowchart showing a processing procedure of the operation of the channel selection control unit 225 of the digital broadcast receiving apparatus in the third embodiment of the present invention. The process of the channel selection control unit 225 in the flowchart shown in FIG. 7 is repeatedly executed when power is supplied to the digital broadcast receiving apparatus and the start condition is satisfied. In the flowchart shown in FIG. 7, this process is started when the reception state of the first system 200 or the second system 210 changes, and the process proceeds to step d1. Since the operation of the channel selection control unit 225 in FIG. 7 is similar to the operation of the channel selection control unit 225 in FIG. 6 described above, only the parts that differ in control operation will be described in detail, and the channel selection control unit 225 in FIG. As for the same parts as the operation of, overlapping explanation is omitted.

  In step d1, it is determined whether reception of digital broadcast signals by the first system 200 and the second system 210 has become impossible at the same time. In step d1, if reception of digital broadcast signals by the first system 200 and the second system 210 becomes impossible at the same time, it is determined that digital broadcasting cannot be received at all, for example, a tunnel has been entered, and video / audio is received. All processing procedures are terminated without switching the decoding unit selection unit 221. In other words, the channel selection control unit 225 does not switch the video / audio decoding unit that outputs the video signal and the audio signal, that is, does not switch the video signal and the audio signal to be output. The selection unit 221 is controlled to end all processing procedures. As a result, the video / audio decoding unit selection unit 221 selects the video / audio decoding unit that was selected immediately before reception of digital broadcast signals by the first system 200 and the second system 210 becomes impossible at the same time. Will remain.

  In step d1, if it is not possible to simultaneously receive the digital broadcast signal by the first system 200 and the second system 210, in other words, the digital broadcast signal is transmitted by the first system 200 or the second system 210. If it can be received, the process proceeds to step d2.

  Since each process of step d2-step d14 is the same as each process of step c1-step c13 of above-mentioned FIG. 6, description of each process of step d2-step d14 is abbreviate | omitted. In the flowchart of FIG. 7, after the completion of each process of step d3, step d7, step d8, step d11, step d13, and step d14, all processing procedures are ended.

  In the flowchart of FIG. 7, step d1, step d2, step d4, step d5, step d9, and step d12 correspond to a reception failure detection step, and step d3, step d6, step d8, step d10, and step d13 are This corresponds to a video / audio selection step, a video display step, and an audio output step.

  As described above, in the digital broadcast receiving apparatus according to the present embodiment, the channel selection control unit 225 determines that the first system 200 and the second system 210 cannot receive a digital broadcast signal, and outputs video. The video / audio decoding unit selection unit 221 is controlled so that the signal and audio signal are not switched. In other words, when the first system 200 and the second system 210 become unable to receive the programs of the weak layer transmission and the strong layer transmission at the same time, the channel selection control unit 225 performs the video search without performing the forward search. The video signal and audio signal output from the weak hierarchical video / audio decoding unit 204 of the first system 200 are kept selected by the / audio decoding unit selection unit 221. As a result, an undesired forward search can be suppressed, so that when the first system 200 and the second system 210 can receive the digital broadcast signal again, before the digital broadcast signal cannot be received. It is possible to immediately output the video and audio of the program of the channel that has been selected.

  For example, when the mobile body enters an area where no digital broadcast such as a tunnel can be received, the digital broadcast receiving apparatus does not perform the forward search operation in step d14 in FIG. As a result, when the mobile body leaves a region where it cannot receive any digital broadcasting such as a tunnel, the program that the user was watching before entering the tunnel can be immediately presented to the user.

  Therefore, in this embodiment, compared with the digital broadcast receiving apparatus of the second embodiment described above, the time during which the user cannot view the program is prevented from being lengthened by the forward search, and the user can view the program. The time to disappear can be shortened.

<Fourth embodiment>
Next, a digital broadcast receiver according to a fourth embodiment of the present invention will be described. FIG. 8 is a block diagram showing a configuration of a digital broadcast receiving device 1A according to the fourth embodiment of the present invention. The digital broadcast receiving apparatus 1A according to the present embodiment is configured by further including a program comparison unit 227 in the configuration of the digital broadcast receiving apparatus 1 according to the first embodiment. Since the digital broadcast receiving device 1A is similar in configuration to the digital broadcast receiving device 1, the same reference numerals are assigned to corresponding portions, and the description common to the first embodiment is omitted.

  The program comparison unit 227 is based on program information acquired by two demultiplexing units 203 and 213 of the first and second systems 200 and 210, for example, PSI and SI, for receiving digital broadcast signals. Thus, for each of the systems 200 and 210, it is detected whether or not the content of the weak hierarchical transmission program and the content of the strong hierarchical transmission program of the channel selected by each of the systems 200 and 210 are the same. The program comparison unit 227 displays a detection result as to whether or not the content of the weak layer transmission program and the content of the strong layer transmission program of the channels selected by the systems 200 and 210 are the same. 225.

  The first demultiplexing unit 203 outputs other information as program information in addition to the PSI and SI described in the first embodiment. Specifically, the first demultiplexing unit 203, as program information related to a weak layer transmission program, includes a program name included in an event information table (abbreviation: EIT) of the weak layer transmission program and At least one of various descriptors including a description of contents, for example, short format event descriptor, extended format event descriptor, etc. is output to the program comparison unit 227, and program information related to a program of strong hierarchical transmission As a program, at least one of various types of information such as a short format event descriptor and an extended format event descriptor including a description of the program name and contents included in the EIT of the program of strong hierarchical transmission The result is output to the comparison unit 227. Although different from the present embodiment, the first demultiplexing unit 203 may output all of the EIT of the weak layer transmission program and the EIT of the strong layer transmission program to the program comparison unit 227.

  Similar to the first demultiplexing unit 203, the second demultiplexing unit 213 outputs other information as program information in addition to the PSI and SI described in the first embodiment. . Specifically, the second demultiplexing unit 213 uses, for example, a short format as a program information related to a weak layer transmission program, a descriptor including a description of the program name and contents included in the EIT of the weak layer transmission program. At least one of various information such as an event descriptor and an extended format event descriptor is output to the program comparison unit 227, and is included in the EIT of the strong hierarchical transmission program as program information related to the strong hierarchical transmission program At least one of various types of information such as a short format event descriptor and an extended format event descriptor is output to the program comparison unit 227. Although different from the present embodiment, the second demultiplexing unit 213 may output all of the EIT of the weak layer transmission program and the EIT of the strong layer transmission program to the program comparison unit 227.

  The program comparison unit 227 determines the content and strongness of the program of weak hierarchical transmission based on the program information output from the first demultiplexing unit 203, specifically, at least one of the various types of information described above. It is detected whether or not the content of the hierarchical transmission program is the same.

  The program comparison unit 227 compares the program names included in the short format event descriptor of the EIT, for example, to determine whether the content of the weak layer transmission program and the content of the strong layer transmission program are the same. Judging.

  Further, the program comparison unit 227 compares the program descriptions included in the short format event descriptor of the EIT, for example, to determine whether the content of the weak hierarchical transmission program and the content of the strong hierarchical transmission program are the same. Judging.

  Further, the program comparison unit 227 compares the contents of the weak hierarchical transmission program and the strong hierarchical transmission program by comparing, for example, the item name and / or item description included in the EIT extended format event descriptor. Are the same.

  Even if the program comparison unit 227 compares the program information other than those described above included in the EIT, the program comparison unit 227 determines whether the content of the weak layer transmission program and the content of the strong layer transmission program are the same. Good.

  Further, the program comparison unit 227 compares a plurality of pieces of program information included in a plurality of event descriptors of the EIT to determine whether the contents of the weak layer transmission program and the contents of the strong layer transmission program are the same. It is also possible to determine whether.

  FIG. 9 is a flowchart showing a processing procedure of the operation of the channel selection control unit 225 of the digital broadcast receiving device 1A according to the fourth embodiment of the present invention. The processing of the channel selection control unit 225 in the flowchart shown in FIG. 9 is repeatedly executed when power is supplied to the digital broadcast receiving device 1A and the start condition is satisfied. In the flowchart shown in FIG. 9, this process is started when the reception state of the first system 200 or the second system 210 changes, and the process proceeds to step e1. The operation of the channel selection control unit 225 in the present embodiment shown in FIG. 9 is similar to the operation of the channel selection control unit 225 in the first embodiment shown in FIG. Only the above will be described in detail, and redundant description of the same parts as the operation of the channel selection control unit 225 in the first embodiment shown in FIG. 3 will be omitted.

  Steps e1 and e2 are the same as the operations of steps b1 and b2 in FIG. In step e3, similarly to step b3 in the first embodiment shown in FIG. 3, the first system 200 cannot receive the weak hierarchy transmission broadcast signal and can receive the strong hierarchy transmission broadcast signal. That is, it is determined whether or not the first system 200 cannot receive the program of the weak layer transmission and can receive the program of the strong layer transmission. In the present embodiment, in step e3, if the first system 200 cannot receive the weak layer transmission program and can receive the strong layer transmission program, the process proceeds to step e4. If both the weak layer transmission program and the strong layer transmission program cannot be received, the process proceeds to step e6.

  In step e4, it is determined whether or not the first system 200 can receive a strong hierarchical transmission program having the same content as the weak hierarchical transmission program of the selected channel. Specifically, first, it is determined whether or not the content of the weak-layer transmission program received by the first system 200 is the same as the content of the strong-layer transmission program. If it is determined that the content of the weak layer transmission program of the channel received in the first system 200 is the same as the content of the strong layer transmission program, the channel of the channel selected in the first system 200 is selected. It is determined that a strong hierarchical transmission program having the same content as the weak hierarchical transmission program can be received, and the process proceeds to step e5.

  If it is determined that the content of the weak layer transmission program received by the first system 200 is not the same as the content of the strong layer transmission program, the weakness of the channel selected for the first system 200 is determined. The video signal and audio signal of the hierarchical transmission program are output from the first weak hierarchical video / audio decoding unit 204, and the strong hierarchical transmission program having the same content as the weak hierarchical transmission program of the selected channel is displayed. Select another channel that is being broadcast, and instruct the channel selection to output the video signal and audio signal of the strong layer transmission program of the channel from the first strong layer video / audio decoding unit 205. Do. In response to this channel selection instruction, the first system 200, as in the above-described forward search, has the same contents as the weak hierarchical transmission program of the channel selected by the user who is the selected channel. A search is made to determine whether there are any other channels broadcasting a hierarchical transmission program. If a channel that broadcasts a program of strong hierarchical transmission having the same content is found by this search, the channel is selected as the further channel and the first system 200 selects the channel. It is determined that a strong hierarchical transmission program having the same content as the weak hierarchical transmission program of a certain channel can be received, and the process proceeds to step e5.

  If a channel broadcasting a program of strong hierarchical transmission having the same content is not found, a program of strong hierarchical transmission having the same content as the weak hierarchical transmission program of the channel selected in the first system 200 is In other words, in the first system 200, it is determined that the strong layer transmission program having the same contents as the weak layer transmission program of the selected channel cannot be received, and the process proceeds to step e6.

  Steps e5, e6, e7, and e8 are the same as the operations of steps b4, b5, b6, and b7 in FIG. In step e9, similarly to step b8 in the first embodiment shown in FIG. 3, the second system 210 cannot receive the broadcast signal of the weak layer transmission and can receive the broadcast signal of the strong layer transmission. In other words, it is determined whether or not the second system 210 cannot receive the program of weak hierarchy transmission and can receive the program of strong hierarchy transmission. In this embodiment, in step e9, if the second system 210 cannot receive the weak layer transmission program and can receive the strong layer transmission program, the process proceeds to step e10. If both the weak layer transmission program and the strong layer transmission program cannot be received, the process proceeds to step e12.

  In step e10, in the same way as in step e4, it is determined whether or not the second system 210 can receive a strong layer transmission program having the same contents as the weak layer transmission program of the selected channel. To do. Specifically, first, it is determined whether or not the content of the weak layer transmission program and the content of the strong layer transmission program received by the second system 210 are the same. If it is determined that the content of the weak layer transmission program of the channel received by the second system 210 is the same as the content of the strong layer transmission program, the channel of the channel selected by the second system 210 It is determined that a strong hierarchical transmission program having the same contents as the weak hierarchical transmission program can be received, and the process proceeds to step e11.

  If it is determined that the content of the weak layer transmission program received by the second system 210 is not the same as the content of the strong layer transmission program, the weakness of the selected channel is determined for the second system 210. The video signal and audio signal of the hierarchical transmission program are output from the second weak hierarchical video / audio decoding unit 214, and the strong hierarchical transmission program having the same content as the weak hierarchical transmission program of the selected channel is output. Select another channel that is being broadcast, and instruct the channel selection to output the video signal and audio signal of the strong layer transmission program of the channel from the second strong layer video / audio decoding unit 215. Do. By this channel selection instruction, the second system 210 performs the same as in the above-described forward search, and the weak hierarchy of the channel that is selected, that is, the channel that broadcasts the same program as the channel selected by the user. A search is made as to whether or not there is another channel that is broadcasting a high-level transmission program having the same contents as the transmission program. If a channel broadcasting a program of strong hierarchical transmission having the same content is found by this search, the channel is selected as the other channel, and the second system 210 selects the channel. It is determined that a strong hierarchical transmission program having the same content as the weak hierarchical transmission program of a certain channel can be received, and the process proceeds to step e11.

  If a channel broadcasting a program of strong hierarchical transmission having the same content is not found, a program of strong hierarchical transmission having the same content as the program of weak hierarchical transmission of the channel selected by the second system 210 is In other words, in the second system 210, it is determined that the strong layer transmission program having the same contents as the weak layer transmission program of the selected channel cannot be received, and the process proceeds to step e12. Steps e11 and e12 are the same as the operations of steps b9 and b10 in FIG.

  As described above, in the digital broadcast receiving apparatus 1A of the present embodiment, the channel selection control unit 225 allows the first system 200 to receive a program with weak hierarchical transmission and the first system 200 to perform strong hierarchical transmission. If the program can be received, it is determined in step e4 whether the content of the weak layer transmission program and the content of the strong layer transmission program of the channel selected by the first system 200 are the same. If they are not the same, the first system 200 is broadcasting a strong layer transmission program having the same contents as the weak layer transmission program of the selected channel, and further selects another channel. Then, the channel selection instruction is issued so that the video signal and audio signal of the program of the strong hierarchical transmission of the channel are output from the first strong hierarchical video / audio decoding unit 205.

  In response to this channel selection instruction, the first system 200 searches for a channel that broadcasts a strong layer transmission program having the same contents as the weak layer transmission program of the selected channel. When a channel that broadcasts a program of strong hierarchical transmission having the same content is found by this search, the channel is selected as the other channel, and the video signal of the program of strong hierarchical transmission of the channel and An audio signal is output from the first strong layer video / audio decoding unit 205. Therefore, when the first system 200 cannot receive the program of the weak layer transmission and the first system 200 can receive the program of the strong layer transmission, the video / audio decoding unit selection unit 221 causes the first system 200 to receive the program of the weak layer transmission. By selecting and outputting a video signal and an audio signal output from one strong layer video / audio decoding unit 205, a weak layer transmission of a channel selected by the user and selected by the first system 200 Even when the content of the program of the program and the content of the program of the strong hierarchical transmission are not the same, the user can view the program having the same content as the program of the selected channel.

  If a channel broadcasting a strong layer transmission program having the same content as the weak layer transmission program of the channel selected in the first system 200 is not found by the above search, the first system 200 is detected. The video signal and audio signal of the strong layer transmission program received in step S5 are not output to the video display unit 222 and audio output unit 223, and the process proceeds to step e6. In step e6, it is determined whether or not the program of weak channel transmission of the channel selected by the second system 210 can be received. If it can be received, the weak class of the second system 210 is determined. The video / audio decoding unit selection unit 221 is controlled to select and output the video signal and audio signal output from the video / audio decoding unit 214.

  Further, when the second system 210 cannot receive the program of the weak layer transmission and the second system 210 can receive the program of the strong layer transmission, the channel is selected by the second system 210 in step e10. It is determined whether or not the contents of the weak-layer transmission program and the strong-layer transmission program of the selected channel are the same. If not, the channel of the selected channel is selected for the second system 210. Broadcasting a strong-layer transmission program having the same contents as the weak-layer transmission program, selecting another channel, and sending the video signal and audio signal of the strong-layer transmission program of that channel to the second strong channel A channel selection instruction is issued so as to be output from the hierarchical video / audio decoding unit 215.

  In response to this channel selection instruction, the second system 210 searches for a channel that broadcasts a strong layer transmission program having the same contents as the weak layer transmission program of the selected channel. When a channel that broadcasts a program of strong hierarchical transmission having the same content is found by this search, the channel is selected as the other channel, and the video signal of the program of strong hierarchical transmission of the channel and The audio signal is output from the second strong layer video / audio decoding unit 215.

  Therefore, the first and second systems 200 and 210 cannot receive the program of weak hierarchical transmission, and the first system 200 has the same strong content as the weak hierarchical transmission program of the selected channel. When the hierarchical transmission program cannot be received and the second system 210 can receive the strong hierarchical transmission program, the video / audio decoding unit selection unit 221 causes the second strong hierarchical video / audio decoding unit to By selecting and outputting the video signal and the audio signal output from 215, the content of the weak layer transmission program of the channel selected by the second system 210 is not the same as the content of the strong layer transmission program. Even in this case, the user can view a program having the same content as the program of the selected channel.

  In the present embodiment, the program comparison step corresponds to step e4 and step e10 shown in FIG. More specifically, the program comparison step determines whether or not the content of the weak layer transmission program and the content of the strong layer transmission program of the channel received by the first system 200 in step e4 are the same. And the step of determining whether or not the content of the weak layer transmission program and the content of the strong layer transmission program received by the second system 210 in step e10 are the same. In the first receiving step, the channel of the first broadcasting station A, which is the channel selected by the user, is received by the first system 200, and the first system 200 of step e4 shown in FIG. Corresponds to the step of instructing channel selection. The second reception step corresponds to the operation of the second system 210 according to the flowchart shown in FIG. 2 and the step of instructing the channel selection to the second system 210 in step e10 shown in FIG. .

  Also, in this embodiment, if it is determined in step e4 that there is no strong layer transmission program having the same content as the weak layer transmission program of the channel selected in the first system 200, the first The video signal and audio signal of the program of the strong hierarchical transmission received by the system 200 are not output to the video display unit 222 and the audio output unit 223, and the process proceeds to step e6, and the possibility of reception by the second system 210 is examined. Move on. In step e13, if it is determined that there is no strong layer transmission program having the same content as the weak layer transmission program of the channel selected in the second system 210, the channel is received by the second system 210. Without outputting the video signal and audio signal of the program of the strong hierarchical transmission to the video display unit 222 and the audio output unit 223, the process proceeds to step e12 and the forward search is executed.

  That is, in the present embodiment, in the first and second systems 200 and 210, the content of the weak channel transmission program and the content of the strong layer transmission program of the selected channel are not the same, and the channel selection is performed. If it is determined that there is no strong hierarchical transmission program having the same content as the weak hierarchical transmission program of the current channel, it is determined in step e1 that the first hierarchical system 200 cannot receive the weak hierarchical transmission program. In steps e3, e6 and e9, the reception of the program of the strong hierarchy transmission by the first system 210, the reception of the program of the weak hierarchy transmission by the second system 210, and the program of the strong hierarchy transmission by the second system 210 If it is determined that at least one of the receptions is possible, the channel selected by the user among the receivable programs, that is, the channel selected by the first system 200 is selected. Program video and audio signals of a program of the same contents of the weak hierarchical transmission is selected and output of.

  Therefore, in the present embodiment, even if the content of the weak-layer transmission program of the channel selected by the user is not the same as the content of the strong-layer transmission program, it is the same as the channel program selected by the user. It is possible to shorten the time during which the program with the contents of “1” cannot be viewed as much as possible.

<Fifth embodiment>
Next, a digital broadcast receiver according to a fifth embodiment of the present invention will be described. Since the configuration of the digital broadcast receiving apparatus of this embodiment is the same as that of the digital broadcast receiving apparatus 1A of the above-described fourth embodiment, the same reference numerals are assigned to corresponding portions, and the fourth embodiment The description common to the embodiment is omitted.

  FIG. 10 is a flowchart showing a processing procedure of the operation of the channel selection control unit 225 of the digital broadcast receiving device 1A according to the fifth embodiment of the present invention. The processing of the channel selection control unit 225 in the flowchart shown in FIG. 10 is repeatedly executed when power is supplied to the digital broadcast receiving device 1A and the start condition is satisfied. In the flowchart shown in FIG. 10, this process is started when the reception state of the first system 200 or the second system 210 changes, and the process proceeds to step f1. The operation of the channel selection control unit 225 in the present embodiment shown in FIG. 10 is the same as the operation of the channel selection control unit 225 in the second embodiment shown in FIG. 6 and the fourth embodiment shown in FIG. Since the operation is similar to the operation of the channel selection control unit 225, only the part in which the control operation is different will be described in detail. The operation of the channel selection control unit 225 in the second embodiment shown in FIG. 6 and the fourth operation shown in FIG. The same description as the operation of the channel selection control unit 225 in the embodiment will be omitted.

  Steps f1, f2, and f3 are the same as the operations of steps c1, c2, and c3 in FIG. In step f4, as in step c4 in the second embodiment shown in FIG. 6, it is determined whether or not the second system 210 can receive a broadcast signal of weak hierarchical transmission, that is, the second system 210 is weak. It is determined whether or not a hierarchical transmission program can be received. In the present embodiment, in step f4, if a program of weak hierarchical transmission can be received by the second system 210, the process proceeds to step f5, and if it cannot be received, the process proceeds to step f7. Steps f5 and f6 are the same as the operations of steps c5 and c6 in FIG.

  In step f7, in the same manner as in step e4 in the fourth embodiment shown in FIG. 9, in the first channel 200, the strong layer transmission having the same content as the weak layer transmission program of the selected channel is performed. It is determined whether or not the program can be received. It is determined that the content of the weak layer transmission program of the channel received by the first system 200 is the same as the content of the strong layer transmission program, or the weak layer transmission program of the selected channel. When a channel that broadcasts a program of strong hierarchical transmission having the same content as the channel is found by the search, the first system 200 performs the transmission of the strong hierarchical transmission of the same content as the weak hierarchical transmission program of the selected channel. It is determined that the program can be received, and the process proceeds to step f8. If a channel broadcasting a strong layer transmission program having the same contents as the weak layer transmission program of the channel selected in the first system 200 is not found, the channel is selected in the first system 200. There is no strong hierarchical transmission program having the same content as the weak hierarchical transmission program of the channel, that is, in the first system 200, the strong hierarchical transmission of the same content as the weak hierarchical transmission program of the selected channel is performed. It is determined that the program cannot be received, and the process proceeds to step f12. Steps f8, f9, f10, and f11 are the same as the operations of steps c7, c8, c9, and c10 in FIG.

  In step f12, similarly to step c11 in the second embodiment shown in FIG. 6, the second system 210 cannot receive the broadcast signal of the weak layer transmission and can receive the broadcast signal of the strong layer transmission. In other words, it is determined whether or not the second system 210 cannot receive the program of weak hierarchy transmission and can receive the program of strong hierarchy transmission. In the present embodiment, if it is determined in step f12 that the second system 210 cannot receive the weak layer transmission program and can receive the strong layer transmission program, the process proceeds to step f13. If it is determined that both the weak layer transmission program and the strong layer transmission program cannot be received in the system 210, the process proceeds to step f15.

  In step f13, in the same way as step e10 in the fourth embodiment shown in FIG. 9, in the second system 210, the strong layer transmission of the same content as the weak layer transmission program of the selected channel is performed. It is determined whether or not the program can be received. It is determined that the content of the weak layer transmission program of the channel received by the second system 210 is the same as the content of the strong layer transmission program, or the program of the weak layer transmission of the selected channel When a channel that broadcasts a program of strong hierarchical transmission having the same content as the channel is found by the search, the first system 200 performs the transmission of the strong hierarchical transmission of the same content as the weak hierarchical transmission program of the selected channel. It is determined that the program can be received, and the process proceeds to step f14. If a channel broadcasting a strong layer transmission program having the same contents as the weak layer transmission program of the channel selected by the second system 210 is not found, the channel is selected by the second system 210. There is no strong hierarchical transmission program with the same content as the weak hierarchical transmission program of the channel, that is, in the second system 210, the strong hierarchical transmission with the same content as the weak hierarchical transmission program of the selected channel It is determined that the program cannot be received, and the process proceeds to step f15. Steps f14 and f15 are the same as the operations of steps c12 and c13 in FIG.

  As described above, in the digital broadcast receiving apparatus 1A of the present embodiment, the channel selection control unit 225 allows the first system 200 to receive a program with weak hierarchical transmission and the first system 200 to perform strong hierarchical transmission. If the program can be received, it is determined whether or not the second system 210 can receive the program of the weak layer transmission. If the program cannot be received, the first system 200 in step f7. Then, it is determined whether or not a strong layer transmission program having the same content as the weak layer transmission program of the selected channel can be received. If a strong layer transmission program having the same content can be received, the video signal and audio signal of the strong layer transmission program are output from the first strong layer video / audio decoding unit 205, and the video display unit 222 and This is given to the audio output unit 223. If it is not possible to receive a program of strong hierarchical transmission with the same content, the process proceeds to step f12, where the second system 210 cannot receive a weak hierarchical transmission program and the second system 210 is a strong hierarchical transmission program. Whether or not can be received.

  Further, when the second system 210 cannot receive the program of the weak layer transmission and the second system 210 can receive the program of the strong layer transmission, the channel selection is performed by the second system 210 in step f13. It is determined whether or not a strong-layer transmission program having the same content as the weak-layer transmission program of the selected channel can be received. The video signal and audio signal of the transmission program are output from the second strong layer video / audio decoding unit 215 and supplied to the video display unit 222 and the audio output unit 223.

  Therefore, as in the fourth embodiment, when the contents of the weak layer transmission program of the channel selected by the first and second systems 200 and 210 are not the same as the content of the strong layer transmission program. However, the user can view a program having the same content as the program of the selected channel.

  In this embodiment, the program comparison step corresponds to step f7 and step f13 shown in FIG. More specifically, the program comparison step determines whether or not the content of the weak layer transmission program and the content of the strong layer transmission program of the channel received by the first system 200 in step f7 are the same. And the step of determining whether or not the content of the weak layer transmission program and the content of the strong layer transmission program of the channel received by the second system 210 in step f13 are the same. In the first reception step, the channel of the first broadcasting station A, which is the channel selected by the user, is received by the first system 200, and the first system 200 of step f7 shown in FIG. Corresponds to the step of instructing channel selection. The second reception step corresponds to the operation of the second system 210 in accordance with the flowchart shown in FIG. 2 and the step of instructing the channel selection to the second system 210 in step f13 shown in FIG. .

  In this embodiment, if it is determined in step f7 that there is no strong layer transmission program having the same content as the weak layer transmission program of the channel selected in the first system 200, the first Without outputting the video signal and audio signal of the program of strong hierarchical transmission received in the system 200 to the video display unit 222 and the audio output unit 223, the process proceeds to step f12, and the possibility of reception in the second system 210 is examined. Move on. In step f13, if it is determined that there is no strong layer transmission program having the same content as the weak layer transmission program of the channel selected in the second system 210, the channel is received by the second system 210. Without outputting the video signal and audio signal of the program of strong hierarchical transmission to the video display unit 222 and the audio output unit 223, the process proceeds to step f15, and the forward search is executed.

  In other words, in the present embodiment, as in the fourth embodiment, the contents of the weak layer transmission program and the strong layer transmission program of the selected channel in the first and second systems 200 and 210 are displayed. When it is determined that there is no strong layer transmission program having the same content as the weak channel transmission program of the selected channel, the content is not the same, and the weak layer transmission program in the first system 200 Cannot be received, and reception of a program of strong layer transmission by the first system 210, reception of a program of weak layer transmission by the second system 210, and reception of a program of strong layer transmission by the second system 210 If it is determined that at least one of the programs is possible, the program selected by the user among the receivable programs, that is, the program of weak hierarchical transmission of the channel selected by the first system 200. Of the same content The set of video and audio signals is selected and output.

  Therefore, in the present embodiment, even if the content of the weak-layer transmission program of the channel selected by the user is not the same as the content of the strong-layer transmission program, it is the same as the channel program selected by the user. It is possible to shorten the time during which the program with the contents of “1” cannot be viewed as much as possible.

  Further, in the digital broadcast receiving apparatus 1A according to the present embodiment, the channel selection control unit 225 allows the first system 200 to receive a program with weak hierarchy transmission and the second system 210 to receive a program with weak hierarchy transmission. If it is determined that reception is possible, the video / audio decoding unit selection unit 221 is controlled to select and output the video signal and audio signal output from the weak layer video / audio decoding unit 214 of the second system 210. . In other words, the channel selection control unit 225, when the first system 200 cannot receive the weak layer transmission program, even if the first system 200 can receive the strong layer transmission program, If it is possible to receive a program of weak layer transmission in 210, the video / audio decoding unit selection unit 221 is controlled so that the video / audio decoding unit that outputs the video signal and the audio signal is used as the first weak layer video / audio. Switching from the decoding unit 204 to the second weak layer video / audio decoding unit 214, the video signal and audio signal of the weak layer transmission program received by the second system 210 are converted into the second weak layer video / audio decoding unit. Output from the unit 214.

  This increases the possibility of outputting high-quality video and audio as compared with the digital broadcast receiving apparatus 1 of the first embodiment described above. In other words, it is possible to increase the possibility that a user can view a program in a weak hierarchy composed of high-quality video and audio. Therefore, it is possible to increase the possibility that a user can view a program of a weak hierarchy composed of high-quality video and audio, and the contents of the program of the weak hierarchy transmission of the channel selected by the user and the strong hierarchy Even when the content of the transmitted program is not the same, the user can view a program having the same content as the selected program.

<Sixth Embodiment>
Next, a digital broadcast receiver according to a sixth embodiment of the present invention will be described. Since the configuration of the digital broadcast receiving apparatus of this embodiment is the same as that of the digital broadcast receiving apparatus 1A of the above-described fourth embodiment, the same reference numerals are assigned to corresponding portions, and the fourth embodiment The description common to the embodiment is omitted.

  FIG. 11 is a flowchart showing a processing procedure of the operation of the channel selection control unit 225 of the digital broadcast receiving device 1A according to the sixth embodiment of the present invention. The process of the channel selection control unit 225 in the flowchart shown in FIG. 11 is repeatedly executed when power is supplied to the digital broadcast receiving apparatus 1A and the start condition is satisfied. In the flowchart shown in FIG. 11, this process is started when the reception state of the first system 200 or the second system 210 changes, and the process proceeds to step g1. The operation of the channel selection control unit 225 in the present embodiment shown in FIG. 11 is the same as that of the third embodiment shown in FIG. 7, the fourth embodiment shown in FIG. 9, and the fifth embodiment shown in FIG. 7 is similar to the operation of each channel selection control unit 225, only the portions where the control operation is different will be described in detail, and the third embodiment shown in FIG. 7 and the fourth embodiment shown in FIG. And the overlapping description is abbreviate | omitted about the part similar to operation | movement of each channel selection control part 225 in 5th Embodiment shown in FIG.

  Steps g1, g2, g3, and g4 are the same as the operations of steps d1, d2, d3, and d4 in FIG. In step g5, similarly to step d5 in the third embodiment shown in FIG. 7, whether or not the second system 210 can receive the broadcast signal of the weak layer transmission, that is, weak in the second system 210. It is determined whether or not a hierarchical transmission program can be received. In the present embodiment, in step g5, if the second system 210 can receive a program of weak hierarchical transmission, the process proceeds to step g6, and if it cannot be received, the process proceeds to step g8. Steps g6 and g7 are the same as the operations of steps d6 and d7 in FIG.

  In step g8, in the same manner as in step e4 in the fourth embodiment shown in FIG. 9, in the first channel 200, the strong layer transmission having the same content as the weak layer transmission program of the selected channel is performed. It is determined whether or not the program can be received. It is determined that the content of the weak layer transmission program of the channel received by the first system 200 is the same as the content of the strong layer transmission program, or the weak layer transmission program of the selected channel. When a channel that broadcasts a program of strong hierarchical transmission having the same content as the channel is found by the search, the first system 200 performs the transmission of the strong hierarchical transmission of the same content as the weak hierarchical transmission program of the selected channel. It is determined that the program can be received, and the process proceeds to step g9. If a channel broadcasting a strong layer transmission program having the same contents as the weak layer transmission program of the channel selected in the first system 200 is not found, the channel is selected in the first system 200. There is no strong hierarchical transmission program having the same content as the weak hierarchical transmission program of the channel, that is, in the first system 200, the strong hierarchical transmission of the same content as the weak hierarchical transmission program of the selected channel is performed. It is determined that the program cannot be received, and the process proceeds to step g13. Steps g9, g10, g11, and g12 are the same as the operations of steps d8, d9, d10, and d11 in FIG.

  In step g13, similarly to step d12 in the third embodiment shown in FIG. 7, the second system 210 cannot receive the broadcast signal of the weak layer transmission and can receive the broadcast signal of the strong layer transmission. In other words, it is determined whether or not the second system 210 cannot receive the program of weak hierarchy transmission and can receive the program of strong hierarchy transmission. In the present embodiment, if it is determined in step g13 that the second system 210 cannot receive the weak layer transmission program and can receive the strong layer transmission program, the process proceeds to step g14. If it is determined that both the weak layer transmission program and the strong layer transmission program cannot be received in the system 210, the process proceeds to step g16.

  In step g14, in the same way as in step e10 in the fourth embodiment shown in FIG. 9, in the second system 210, the strong layer transmission of the same content as the weak layer transmission program of the selected channel is performed. It is determined whether or not the program can be received. It is determined that the content of the weak layer transmission program of the channel received by the second system 210 is the same as the content of the strong layer transmission program, or the program of the weak layer transmission of the selected channel When a channel that broadcasts a program of strong hierarchical transmission having the same content as the channel is found by the search, the first system 200 performs the transmission of the strong hierarchical transmission of the same content as the weak hierarchical transmission program of the selected channel. It is determined that the program can be received, and the process proceeds to step g15. If a channel broadcasting a strong layer transmission program having the same contents as the weak layer transmission program of the channel selected by the second system 210 is not found, the channel is selected by the second system 210. There is no strong hierarchical transmission program with the same content as the weak hierarchical transmission program of the channel, that is, in the second system 210, the strong hierarchical transmission with the same content as the weak hierarchical transmission program of the selected channel It is determined that the program cannot be received, and the process proceeds to step g16. Steps g15 and g16 are the same as the operations of steps d13 and d14 in FIG.

  As described above, in the digital broadcast receiving apparatus 1A of the present embodiment, the channel selection control unit 225 cannot receive the program whose first system 200 is weakly transmitted, as in the fifth embodiment. When the first system 200 is capable of receiving a program with strong hierarchical transmission, it is determined whether the second system 210 is capable of receiving a program with weak hierarchical transmission. In step g8, it is determined whether or not the first system 200 can receive a strong layer transmission program having the same contents as the weak layer transmission program of the selected channel. If a strong layer transmission program having the same content can be received, the video signal and audio signal of the strong layer transmission program are output from the first strong layer video / audio decoding unit 205, and the video display unit 222 and This is given to the audio output unit 223. If it is not possible to receive a program of strong hierarchical transmission having the same content, the process proceeds to step g13, where the second system 210 cannot receive a weak hierarchical transmission program and the second system 210 is a strong hierarchical transmission program. Whether or not can be received.

  Further, when the second system 210 cannot receive the program of the weak layer transmission and the second system 210 can receive the program of the strong layer transmission, the channel selection is performed by the second system 210 in step g14. It is determined whether or not a strong-layer transmission program having the same content as the weak-layer transmission program of the selected channel can be received. The video signal and audio signal of the transmission program are output from the second strong layer video / audio decoding unit 215 and supplied to the video display unit 222 and the audio output unit 223.

  Therefore, as in the fourth and fifth embodiments, the contents of the weak layer transmission program of the channel selected by the first and second systems 200 and 210 are the same as the content of the strong layer transmission program. Even if not, the user can view a program having the same contents as the program of the selected channel.

  In the present embodiment, the program comparison step corresponds to step g8 and step g14 shown in FIG. More specifically, the program comparison step determines whether or not the content of the weak layer transmission program and the content of the strong layer transmission program received in the first system 200 in step g8 are the same. And the step of determining whether or not the content of the weak layer transmission program and the content of the strong layer transmission program received by the second system 210 in step g14 are the same. In the first receiving step, the channel of the first broadcasting station A, which is the channel selected by the user, is received by the first system 200, and the first system 200 of step g8 shown in FIG. Corresponds to the step of instructing channel selection. The second reception step corresponds to the operation of the second system 210 in accordance with the flowchart shown in FIG. 2 and the step of instructing the second system 210 in step g14 shown in FIG. .

  Further, in this embodiment, as in the fourth and fifth embodiments, in step g8, the strong layer transmission having the same contents as the weak layer transmission program of the channel selected in the first system 200 is performed. If it is determined that there is no such program, the video signal and audio signal of the strong layer transmission program received by the first system 200 are not output to the video display unit 222 and the audio output unit 223, and the process proceeds to step g13. Then, the examination of whether or not reception is possible in the second system 210 is started. In step g14, if it is determined that there is no strong hierarchical transmission program having the same content as the weak hierarchical transmission program of the channel selected in the second system 210, the channel is received by the second system 210. Without outputting the video signal and audio signal of the program of strong hierarchical transmission to the video display unit 222 and the audio output unit 223, the process proceeds to step g16, and the forward search is executed.

  That is, in the present embodiment, similar to the fourth and fifth embodiments, the contents of the weak layer transmission program of the selected channel and the strong layer transmission in the first and second systems 200 and 210. If it is determined that there is no strong layer transmission program having the same content as the weak channel transmission program of the selected channel, the content of the first channel 200 is not the same. The transmission program cannot be received, and the first system 210 receives the strong layer transmission program, the second system 210 receives the weak layer transmission program, and the second system 210 receives the strong layer transmission program. If it is determined that at least one of the receptions is possible, the channel selected by the user among the receivable programs, that is, the weak hierarchy of the channels selected by the first system 200 Same as transmission program Video and audio signals of the content of the program is selected and output.

  Therefore, in the present embodiment, even if the content of the weak-layer transmission program of the channel selected by the user is not the same as the content of the strong-layer transmission program, it is the same as the channel program selected by the user. It is possible to shorten the time during which the program with the contents of “1” cannot be viewed as much as possible.

  In the digital broadcast receiving apparatus 1A of the present embodiment, when the channel selection control unit 225 determines that the first system 200 and the second system 210 cannot receive the digital broadcast signal, the video signal to be output and The video / audio decoding unit selection unit 221 is controlled so as not to switch the audio signal. In other words, when the first system 200 and the second system 210 become unable to receive the programs of the weak layer transmission and the strong layer transmission at the same time, the channel selection control unit 225 performs the video search without performing the forward search. The video signal and audio signal output from the weak hierarchical video / audio decoding unit 204 of the first system 200 are kept selected by the / audio decoding unit selection unit 221.

  As a result, an undesired forward search can be suppressed, so that when the first system 200 and the second system 210 can receive the digital broadcast signal again, before the digital broadcast signal cannot be received. It is possible to immediately output the video and audio of the program of the channel that has been selected.

  For example, when the mobile body enters an area where no digital broadcast such as a tunnel can be received, the digital broadcast receiving apparatus does not perform the forward search operation in step g16 in FIG. As a result, when the mobile body leaves a region where it cannot receive any digital broadcasting such as a tunnel, the program that the user was watching before entering the tunnel can be immediately presented to the user.

  Therefore, in this embodiment, compared with the digital broadcast receiving apparatus of the fifth embodiment described above, the time during which the user cannot view the program is prevented from being lengthened by the forward search, and the user can view the program. In addition to shortening the time to be lost, the user can also select the selected program even if the contents of the weak layer transmission program of the channel selected by the user and the content of the strong layer transmission program are not the same. Can watch programs with the same content.

It is a block diagram which shows the structure of the digital broadcast receiver 1 in the 1st Embodiment of this invention. It is a flowchart which shows the process sequence of operation | movement of the channel selection control part 225 of the digital broadcast receiver 1 in the 1st Embodiment of this invention. It is a flowchart which shows the process sequence of operation | movement of the channel selection control part 225 of the digital broadcast receiver 1 in the 1st Embodiment of this invention. It is a figure which shows the receivable area of the broadcast signal transmitted from the 1st broadcast station A and the 2nd broadcast station B. It is a figure which shows the receivable area of the broadcast signal transmitted from the 1st broadcast station A and the 2nd broadcast station B. It is a flowchart which shows the process sequence of operation | movement of the channel selection control part 225 of the digital broadcast receiver in the 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of operation | movement of the channel selection control part 225 of the digital broadcast receiver in the 3rd Embodiment of this invention. It is a block diagram which shows the structure of 1 A of digital broadcast receivers in the 4th Embodiment of this invention. It is a flowchart which shows the process sequence of operation | movement of the channel selection control part 225 of 1 A of digital broadcast receivers in the 4th Embodiment of this invention. It is a flowchart which shows the process sequence of operation | movement of the channel selection control part 225 of 1 A of digital broadcast receivers in the 5th Embodiment of this invention. It is a flowchart which shows the process sequence of operation | movement of the channel selection control part 225 of 1 A of digital broadcast receivers in the 6th Embodiment of this invention.

Explanation of symbols

  1, 1A digital broadcast receiver, 200 first system, 201 first tuner unit, 202 first demodulation unit, 203 first demultiplexing unit, 204 first weak layer video / audio decoding unit, 205 First strong layer video / audio decoding unit, 210 second system, 211 second tuner unit, 212 second demodulation unit, 213 second demultiplexing unit, 214 second weak layer video / audio decoding , 215 second strong layer video / audio decoding unit, 221 video / audio decoding unit selection unit, 222 video display unit, 223 audio output unit, 224 reception impossible detection unit, 225 channel selection control unit, 226 channel storage unit, 227 Program comparison unit.

Claims (4)

Channels are selected by receiving digital broadcast signals transmitted from broadcast stations, and video signals and audio signals of relatively weak weak layer transmission programs on the selected channels are output from the weak layer video / audio decoding unit. A first system and a second system for outputting a video signal and an audio signal of a relatively strong strong layer transmission program from the strong layer video / audio decoding unit;
First system weak hierarchical video / audio decoding unit, first system strong hierarchical video / audio decoding unit, second system weak hierarchical video / audio decoding unit, and second system strong hierarchical video / audio decoding unit A video / audio decoding unit selection unit that selects and outputs a video signal and an audio signal output from any one of the units;
A video display unit for displaying video based on a video signal output from the video / audio decoding unit selection unit;
An audio output unit that outputs audio based on an audio signal output from the video / audio decoding unit selection unit;
A non-reception detection unit that detects that each channel cannot receive a program of weak layer transmission or strong layer transmission of a selected channel;
A channel selection control unit that performs channel selection instructions for the first and second systems and controls the video / audio decoding unit selection unit based on a detection result of the reception impossibility detection unit ;
Using the program information included in the digital broadcast signal received by the first system, the content of the weak layer transmission program and the content of the strong layer transmission program of the channel selected by the first system are obtained. The contents of the program of the weak layer transmission of the channel selected by the second system using the program information included in the digital broadcast signal received by the second system by detecting whether or not they are the same And a program comparison unit for detecting whether or not the content of the program of strong hierarchical transmission is the same ,
The first system selects a channel selected by the user,
The second system broadcasts a weak layer transmission program or a strong layer transmission program having the same contents as at least one of a weak layer transmission program and a strong layer transmission program of a channel selected by the user. Select other channels
The tuning control unit is
If it is determined that the first system is capable of receiving a program of weak hierarchy transmission, the video signal and the audio signal output from the weak hierarchy video / audio decoding unit of the first system are selected and output. Controlling the video / audio decoding unit selection unit;
The first system cannot receive a program of weak layer transmission, and receives a program of strong layer transmission by the first system, reception of a program of weak layer transmission by the second system, and the second If it is determined that at least any one of the programs of the strong layer transmission by the system is possible, the video signal and the audio signal are selected and output from any one of the receivable programs. Control the video / audio decoder selection unit,
When the first and second systems determine that the digital broadcast signal cannot be received simultaneously, the video / audio decoding unit selection unit is controlled so as not to switch the video signal and audio signal to be output ,
The program comparing unit selects the channel selected in the first system so that the content of the weak layer transmission program and the content of the strong layer transmission program are not the same, and the channel selected in the second system. If at least one of the contents of the weak layer transmission program content and the strong layer transmission program content of the channel is not the same is detected, the system is detected. The video signal and audio signal of the weak layer transmission program of the channel selected by the channel are output from the weak layer video / audio decoding unit, and the same contents as the weak layer transmission program of the channel selected by the system are output. Broadcasting a program of strong hierarchical transmission, further selecting another channel, and transmitting the video signal and audio signal of the strong hierarchical transmission program of the further another channel to the strong hierarchical video / audio decoding unit Digital broadcast receiving apparatus and performs channel selection instruction to al outputs. The tuning control unit is
It is determined that there is no strong layer transmission program having the same content as the weak layer transmission program of the channel selected in the system detected by the program comparison unit as not being the same and the non-identity detected. The first system cannot receive a program of weak layer transmission, and receives a program of strong layer transmission by the first system, reception of a program of weak layer transmission by the second system. If it is determined that at least one of the programs of the strong layer transmission by the second system is received, the program of the weak layer transmission of the channel selected by the user among the receivable programs. 2. The digital broadcast receiving apparatus according to claim 1 , wherein the video / audio decoding unit selection unit is controlled so as not to select a video signal and an audio signal of a program having contents different from those of the program . The digital broadcast signal transmitted from the broadcast station is received, the channel selected by the user is selected, the video signal and audio signal of the relatively weak transmission program of the selected channel, and the relative A first receiving step of outputting a video signal and an audio signal of a strong strong layer transmission program;
Receiving a digital broadcast signal transmitted from a broadcasting station, weak layer transmission or strong layer of the same content as at least one of a weak layer transmission program and a strong layer transmission program of the channel selected by the user Select other channels that are broadcasting the transmission program, and the video signal and audio signal of the relatively weak layer transmission program of the selected channel, and the video signal of the relatively strong layer transmission program And a second receiving step for outputting an audio signal;
In each reception step, it is detected that it is impossible to receive the program of the weak channel transmission or the strong channel transmission of the selected channel;
Based on the detection result in the reception impossible detection step, the weak layer transmission and strong layer transmission program received in the first reception step, and the weak layer transmission and strong layer transmission program received in the second reception step A video / audio selection step of selecting and outputting a video signal and an audio signal of any one of the programs;
A video display step for displaying video based on the video signal output in the video / audio selection step;
An audio output step for outputting audio based on the audio signal output in the video / audio selection step ;
Using the program information included in the digital broadcast signal received in the first reception step, the contents of the weak layer transmission program and the strong layer transmission program of the channel selected in the first reception step are: The contents of the program of the weak layer transmission of the channel selected in the second reception step using the program information included in the digital broadcast signal received in the second reception step. And a program comparison step for detecting whether or not the content of the program of strong hierarchical transmission is the same ,
In the first receiving step,
If it is detected in the program comparison step that the contents of the channel selected in the first reception step are not the same as the contents of the weak layer transmission program and the strong layer transmission program, Outputs video and audio signals for weak-layer transmission programs, and broadcasts strong-layer transmission programs with the same content as weak-layer transmission programs for the selected channel. And outputting a video signal and an audio signal of the program of strong hierarchical transmission of the further other channel,
In the second receiving step,
If it is detected in the program comparison step that the contents of the channel selected in the second reception step are not the same as the contents of the weak layer transmission program and the strong layer transmission program, Outputs video and audio signals for weak-layer transmission programs, and broadcasts strong-layer transmission programs with the same content as weak-layer transmission programs for the selected channel. And outputting a video signal and an audio signal of the program of strong hierarchical transmission of the further other channel,
In the video / audio selection step,
When it is determined in the first reception step that the program of weak layer transmission is receivable, the video signal and audio signal of weak layer transmission output in the first reception step are selected and output,
In the first reception step, the program of weak layer transmission is not receivable, the reception of the program of strong layer transmission in the first reception step, and the program of weak layer transmission in the second reception step If it is determined that at least one of reception and reception of a program of strong hierarchical transmission in the second reception step is possible, the video signal and audio signal of any one of the receivable programs Select and output
A digital broadcast receiving method, characterized in that when it is determined that the digital broadcast signal cannot be received simultaneously in the first and second receiving steps, the video signal and audio signal to be output are not switched. In the video / audio selection step,
In the program comparison step, the contents of the weak layer transmission program and the strong layer transmission program of the channel selected in at least one of the first and second reception steps are not the same. And when it is determined that there is no strong layer transmission program having the same content as the weak layer transmission program of the selected channel in the reception step in which it is detected that the channel is not the same, the first step And receiving the program of weak layer transmission in the first receiving step, receiving the program of weak layer transmission in the second receiving step, and If it is determined that at least one of the reception of strong hierarchical transmission programs in the second reception step is possible, among the receivable programs, the channel selected by the user is selected. Digital broadcast receiving method according to claim 3, characterized in that to avoid selecting a program video and audio signals of a program different from the content of the weak layer transmission Le.

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