JP4557764B2 - Digital data receiver - Google Patents

Description

  The present invention relates to a digital data receiver such as a digital broadcast receiver capable of switching and using a plurality of types of reception services.

  In Japanese terrestrial digital television broadcasting, it is possible to perform hierarchical transmission in which a plurality of layers having different transmission characteristics are transmitted simultaneously. Therefore, for example, different types of encoded digital data (MPEG2, MPEG4, H.264, etc.) are received from the broadcast wave of the same channel by digital broadcasting, and one type of encoded digital data is encoded according to the reception situation. A technique for switching to digital data is known (for example, Patent Document 1).

  However, when switching to different types of encoded digital data depending on the reception situation, the video data decoded from each encoded digital data is not always completely synchronized, so switching Therefore, there is a disadvantage that the video cannot be switched seamlessly. Also, if the reception status of one encoded digital data deteriorates, the reception status of the other encoded digital data is not necessarily good, and it may not be possible to provide a good video even after switching. there were. Further, if switching is performed frequently, there is a disadvantage that the user feels uncomfortable.

JP 2002-158726 A (page 2, FIG. 1)

  Therefore, an object of the present invention is to provide a digital data receiver capable of optimizing conditions for switching a plurality of types of reception services depending on the situation.

  In addition, the present invention can optimize the switching of data in a plurality of types of reception services depending on the situation even when moving to a position where broadcast waves of other channels that broadcast the same program can be received. An object is to provide a digital data receiver.

In order to solve the above problems, a digital data receiver according to the present invention includes a first receiver, a second receiver, a first data generator, a second data generator,
The first receiver and the second receiver are tuned to the first channel, the data related to the first service of the first channel is output from the first data generator, and the second of the first channel is output from the second data generator. Output data related to the service,
The first receiving unit is tuned to the first channel and the second receiving unit is tuned to the second channel, and the data related to the second service of the first channel is output from the first data generating unit and the second data generating unit And a control unit that performs control to output data related to the second service of the second channel. For example, even when the mobile service related to the first channel and the mobile service related to the first channel are moved from the area where the fixed service and mobile service related to the first channel can be received, Configured to output data from multiple sources.

  In the digital data receiver according to the present invention, the control unit switches the tuning channel of the first and second receiving units based on the network follow information, or the network follow information, the position information of the digital data receiver, and the map It is preferable to carry out based on information. The digital data receiver is configured to be able to determine in which area the data related to what type of service in which channel can be received.

  Further, in the digital data receiver according to the present invention, a switching unit that performs a switching process for outputting only one of the data output from the first data generation unit and the data output from the second data generation unit. It is preferable to have. For example, even if the mobile service related to the first channel and the mobile service related to the first channel move from the area where the fixed service and mobile service can be received with respect to the first channel, It is configured so that optimum data can be switched and output in the area.

  According to the digital data receiver of the present invention, since the reception service is switched according to the state detection signal, it is possible to always output optimum video or audio data regardless of the external environment.

  Further, according to the digital data receiver of the present invention, it is possible to output optimum data from a plurality of types of reception services in a plurality of channels broadcasting the same program.

  A digital data (broadcast) receiver according to the present invention will be described below with reference to the drawings.

  The digital data receiver according to the present invention is a receiver compatible with Japanese terrestrial digital television broadcasting. In digital terrestrial television broadcasting, the bandwidth for one channel is divided into 13 segments, 12 of which are used for fixed services (for home use), and the remaining 1 segment is used for mobile services (mobile receiver terminals). Assigned for use. The fixed service employs the MPEG2 system as a data compression system, and the mobile service employs the H.264 data compression system. The H.264 system (one of the video compression systems also known as MPEG-4 Part 10) (or the MPEG4 system) is employed. Encoded digital data for fixed services is encoded by the MPEG2 system and is high quality, but the bit rate is high, so noise resistance is weak, and good when the distance from the broadcast station is long. Reception may be difficult. On the other hand, encoded digital data for mobile services is H.264. H.264 format (or MPEG4 format) encoded with a lower bit rate than the MPEG2 format, so it has high noise resistance and can be received well even when the distance from the broadcasting station is longer. It becomes possible. In the digital data receiving apparatus according to the present invention, the fixed service and the portable service, and further the analog TV are switched according to the situation, and the optimum video and audio are always provided.

  FIG. 1 is a block diagram showing an outline of a digital data receiver 100 according to the present invention.

  The digital data receiver 100 includes a master receiving unit 10, a slave receiving unit 20, an analog tuner unit 30, a combining unit 40, a demultiplexing unit 41, a decoding unit 50, a hard disk device (HDD) 60, an audio switching processing unit 70, a D / D A converter 71, video switching processing unit 80, scaling processing unit 81, drawing processing unit 82, GDC (graphic) drawing processing unit 83, control unit 90, RAM 91, ROM 92, I / O 93, IC card slot 94, SD card Slot 95, system bus 96, and the like.

  The digital data receiver 100 is connected to the first antenna 110, the second antenna 120, the third antenna 130, the navigation device 150, the in-vehicle speaker 170, the in-vehicle display unit 180, the remote controller 190, and the like. The digital data receiver 100 includes any one or more of the antennas 110 to 130, the navigation device 150, the in-vehicle speaker 170, the in-vehicle display unit 180, and the remote controller 190, and any one or more. May be included.

  The digital data receiver 100 is configured to be controlled by operation inputs from various input devices (buttons, touch panel, etc.) provided in the in-vehicle display unit 180 and / or the remote controller 190.

  The master reception unit 10 includes a first tuner unit 11 and a first OFDM demodulation unit 12, and the slave reception unit 20 includes a second tuner unit 21 and a second OFDM demodulation unit 22.

  The decoder unit 50 includes a first audio decoder 51 that decodes audio data for fixed services, a second audio decoder 52 that decodes audio data for mobile services, a first video decoder 53 that decodes video data for fixed services, A second video decoder 54 for decoding video data for mobile service and a data decoder 55 for decoding digital broadcast data are provided. Each of the decoders 51 to 55 may be configured as an individual electronic circuit having each function, or may be a single decoder device in terms of hardware that achieves each function in software. . Furthermore, the decoding unit 50 is configured to be able to vary the data object to be decoded in accordance with a control signal from the control unit 90 described later.

The first and second tuner units 11 and 21 receive the same broadcast wave according to the control signal from the control unit 90 from the first and second antennas 110 and 120 attached to different positions of the vehicle body, respectively. The OFDM (Orthogonal Frequency Division Multiplexing) signal existing in the reception band is extracted and sent to the first and second OFDM demodulation processing units 12 and 22, respectively. The first and second tuner units 11 and 21 transmit the electric field strength signals S ₁ and S ₂ when receiving broadcast waves to the control unit 90 via the system bus 96, respectively.

The first and second OFDM demodulation processing units 12 and 22 are configured to demodulate the OFDM signal, extract a digital signal, perform digital signal error correction processing, output a TS packet signal, and send the TS packet signal to the combining unit 40 . The first and second OFDM demodulation processing units 12 and 22 incorporate an AGC (Auto Gain Control) circuit, and feedback the received signals from the first and second tuner units 11 and 21 so as to obtain a desired reception level. Take control. Furthermore, the first and second OFDM demodulation processing units 12 and 22 send correction error signals RS ₁ and RS ₂ indicating that error correction cannot be performed by the error correction processing via the system bus 96 to the control unit 90. Send to.

  The synthesizer 40 is configured to synthesize the TS (transport stream) packet signals from the first and second OFDM demodulation processors 12 and 22 for all the spectra.

  Therefore, if a sufficient demodulated signal is output from either the master receiving unit 10 or the slave receiving unit 20, good video and audio can be reproduced. That is, in this embodiment, a diversity reception technique for mobile reception is employed in which a plurality of antennas are arranged in a vehicle and the received signals are combined so that the power is as high as possible and the distortion is reduced. In the present embodiment, two sets of receiving units are provided, but more receiving sets may be provided, or only one receiving set may be used.

  The demultiplexing unit 41 demultiplexes the TS packet signal from the synthesizing unit 40, sends TS packets related to voice for fixed services to the first voice decoder 51, and TS packets related to voice for portable services to the second voice decoder 52. TS packets related to video for fixed services are transmitted to the first video decoder 53, TS packets related to video for mobile services are transmitted to the second video decoder 54, and TS packets related to digital data for data broadcasting are transmitted to the data decoder 55, respectively. . In addition, the demultiplexing unit 41 transmits a TS error signal indicating that the TS packet includes an error to the control unit 90 via the system bus 96.

  The first audio decoder 51 decodes the data included in the TS packet received from the demultiplexing unit 41 to generate audio data for fixed service (MPEG2 system). Data included in the received TS packet is decoded to generate audio data for mobile service (H.264 system or MPEG4 system).

  The first video decoder 53 decodes data included in the TS packet received from the demultiplexing unit 41 to generate video data for a fixed service (MPEG2 system). The second video decoder 53 includes the demultiplexing unit 41. The data included in the TS packet received from is decoded to generate video data for the mobile service (H.264 system or MPEG4 system).

  The data decoder 55 decodes the data included in the TS packet received from the demultiplexing unit 41 to generate EPG (program guide information) data and the like, and outputs the generated data to the control unit 90 via the system bus 96. Configured to do.

  The audio data from the first audio decoder 51 and the second audio decoder is transmitted to the audio switching processing unit 70 via the hard disk drive (HDD) 60, and the video from the first video decoder 53 and the second video decoder is transmitted. The data is transmitted to the voice switching processing unit 70 via the HDD 60. A method of using the HDD 60 will be described later.

  In the voice switching processing unit 70, switching control is performed so that either one for a fixed service or one for a portable service is output in accordance with a control signal from the control unit 90, and is mounted on the vehicle via the D / A converter 71. It was configured to output from the speaker 170. The voice switching processing unit 70 receives an analog TV broadcast voice signal received by the analog tuner unit 30 and replaces the voice data for the fixed service and the portable service according to the control signal from the control unit 90. It was configured to be able to output.

  In the video switching processing unit 80, switching control is performed so that either one for the fixed service or the portable service is output in accordance with the control signal from the control unit 90, and the video switching processing unit 80 outputs the signal to the scaling processing unit 81. Configured. The video switching processing unit 80 receives the analog TV broadcast video signal received by the analog tuner unit 30 and replaces the audio data for the fixed service and the portable service according to the control signal from the control unit 90. It was configured to be able to output.

  In the scaling processing unit 81, the image size for the selected fixed service (SD: 720 × 480 pixels, HD: 1920 × 1080 pixels or 720P: 1280 × 720 pixels) or the image size for mobile services (QCIF: 176 × 144) Pixels, QVGA: 320 × 240 pixels or 16: 9 size: 320 × 180 pixels) are configured to be resized to fit the screen size (800 × 640 pixels) of the in-vehicle display unit 180. Note that the above-described screen size of the in-vehicle display unit 50 is an example, and displays having other image sizes can be used.

  The GDC rendering processing unit 83 performs bitmap development based on graphic data for data broadcasting received from the data decoder 55, still image data received from the RAM 91 or ROM 92, etc., and generates an image or video. Configured.

  The drawing processing unit 82 is configured to generate display data by combining the video data received from the scaling processing unit 81 and the image or video received from the GDC drawing processing unit 83, and display the data on the in-vehicle display unit 180. In addition, the drawing processing unit 82 performs a calculation process including a storage unit such as a VRAM for temporarily storing video data, an interpolation process, a replacement process, and the like for generating still image data (freeze image data) from the video data. It is preferable to have an arithmetic processing unit to perform.

The control unit 90 operates in accordance with a program installed in advance using the RAM 91 and the ROM 92, and controls each element connected to the system bus 96. The control unit 90 also includes electric field strength signals S ₁ and S ₂ from the first and second tuner units 11 and 21, correction error signals RS ₁ and RS ₂ from the first and second OFDM demodulation processing units 12 and 22, The TS error signal from the demultiplexing unit 41 and the motion vector amount error rate signals MV ₁ and MV ₂ from the first and second video decoders 53 and 54 are received, and the optimal video is based on all or part of each signal. It was configured to perform switching control to output data and audio data. In addition, when the control unit 90 determines that the video data for the fixed service and the mobile service is not good, the control for switching to the video output of the analog TV received by the analog tuner unit 30 or the control for switching to the still image. Configured to do. Further, when the control unit 90 determines that the voice data for the fixed service and the portable service is not good, the control unit 90 switches to analog TV audio output received by the analog tuner unit, or to a mute signal (silence). Switching control is performed.

  The IC card slot 94 is used for connecting an IC card storing a password for decryption. The SD card slot 95 is used for upgrading the software of the digital data receiver.

  FIG. 2 is a diagram illustrating a configuration of TS (Transport Stream) and PES (Packetized Elementary Stream).

  As shown in FIG. 2A, the TS is composed of a plurality of TS packets, and one TS packet has a fixed length of 188 bytes. The TS packet includes a 4-byte header part (TSH) and a 184-byte data part. The header part includes a PID (packet ID) for identifying a 13-bit TS packet, a TS error bit indicating whether or not there is an error in the TS packet, and the like. The data portion includes data such as video, audio, and data for data broadcasting. The TS packet includes a packet including video data, a packet including audio data, a packet including data for data broadcasting, a packet including only a NULL code, and the type of a specific packet depends on the PID. Judgment can be made.

  The video PES shown in FIG. 2B shows video packets reconstructed from video data included in a plurality of TS packets in the first or second video decoders 53 and 54. One packet is not a fixed length, but is composed of a header (PH) and a data part composed of encoded data. The header part (PH) includes a PCR (Program Clock Reference) indicating a program time reference value, presentation time information (PTS: Presentation Time Stamp) for synchronizing video data and audio data, A CRC (Cyclic Redundancy Check) code that can be used to detect errors is included. When the encoded data in the data part is decoded, decoding time information (DTS: Decoding Time Stamp) indicating decoding time is attached.

  The audio PES shown in FIG. 2C shows an audio packet reconstructed from audio data included in a plurality of TS packets in the first or second audio decoder 51 or 52. One packet is not a fixed length, but is composed of a header (PH) and a data part composed of encoded data. Similarly, the header part (PH) includes a PCR, a PTS, and a CRC code. When the encoded data in the data part is decoded, DTS is added.

  The timing of the decoded video data and audio data for fixed service and the decoded video data and audio data for mobile service is determined by any one of the above-described PCR, PTS and DTS, It can be determined by a plurality.

  FIG. 3 is a diagram showing an outline of the data structure of the video output from the video decoders 53 and 54.

  In the figure, one frame (picture) 300 includes a plurality of slices 301 obtained by cross-sectioning one frame into a strip shape, and each slice includes a plurality of macroblocks. Each macro block includes, for example, luminance data and color difference data of 16 × 16 pixels.

  The first and second video decoders 53 and 54 detect motion vector amount data added for each macroblock which is a unit of motion compensation from the encoded digital data, and the motion vector amount for each macroblock is an abnormal value. The motion vector amount error rate signal indicating how many of the macroblocks constituting one frame have an abnormal value in units of one frame is sent to the control unit 90. The system is configured to transmit via the system bus 96. Further, the control unit 90 can detect a micro block indicating an abnormal value for each frame based on data from the first and second video decoders 53 and 54.

  FIG. 4 is a diagram showing an example of a processing flow for switching between fixed service, portable service, and analog TV in the digital data receiver according to the present invention.

  Switching in the processing flow shown in FIG. 4 is performed at the same time for video and audio, but switching control can also be performed individually. In addition, the switching condition (whether it is successfully received or satisfies the return condition, etc.) will be described later. Further, the processing flow shown in FIG. 4 is mainly executed by the control unit 90 of the digital data receiver 100 in cooperation with each element of the digital data receiver 100 according to a program installed in advance. The digital data receiver 100 is assumed to be in a state where the power is turned on and various functions can operate. The master receiver 10 and the slave receiver 20 are tuned to the same channel, and the analog TV tuner 30 broadcasts the same broadcast program as the channel to which the master receiver 10 and the slave receiver 20 are tuned. It is assumed that it is tuned to a channel of an analog TV.

  The control unit 90 determines whether the current time is simultaneous broadcasting (S401). The simulcast is a fixed service based on encoded digital data encoded by the MPEG2 system, This means that mobile services having the same content by mobile broadcasting using encoded digital data encoded by the H.264 system (or MPEG4 system) are transmitted hierarchically on the same broadcast channel. Whether the reception channel is simultaneous broadcasting is determined by the control unit 90 based on the data in the data for data broadcasting.

  If it is determined in S401 that the broadcast is simulcast, the control unit 90 determines whether the currently output data is video and audio for a fixed service (S402).

  If it is determined in S402 that the service is a fixed service, it is determined whether video and audio for the fixed service are received well (S403). If it is determined that the service is good, The control unit 90 controls the audio switching processing unit 70 and the video switching processing unit 80 so as to output video and audio for fixed services (S413).

  In S403, when it is determined that the fixed service is not received well, it is determined whether the video and audio for the mobile service are received well (S404), and is determined to be good. If so, the control unit 90 controls the audio switching processing unit 70 and the video switching processing unit 80 so as to output video and audio for the mobile service (S412).

If it is determined in S404 that the mobile service is not received well, it is determined whether the video and audio of the analog TV are received well (S405), and it is determined that the mobile service is good. In that case, the control unit 90 controls the audio switching processing unit 70 and the video switching processing unit 80 so as to output the video and audio of the analog TV (S414). Whether or not the analog TV video and audio are well received can be determined by the control unit 90 using the electric field strength signal S ₃ received from the analog TV tuner unit 30.

  If it is determined in S405 that the analog TV is not received well, the control unit 90 controls the audio switching processing unit 70 to output a mute output (silence) from the in-vehicle speaker 170, and freezes the image. The video switching processing unit 80 is controlled to display the (still image) on the in-vehicle display unit 180 (S415). As for the sound, it is rare that the analog TV sound output is interrupted for a long period of time.

The freeze image may be created from a video frame for a fixed service or a video frame for a mobile service, or still image data stored in advance in the ROM 92 or the like may be used. When creating a freeze image from a video frame for fixed services, the control unit 90 mainly uses macroblocks having normal values in the video frames for fixed services, and data corresponding to macroblocks having abnormal values is Then, a complementary process such as a complementary process using the data of surrounding macroblocks is performed to generate freeze image (still image) data. For example, in the complement processing, when the motion vector amount of the macro block n ₅ in FIG. 3 indicates an abnormal value, the data of the eight macro blocks n _{1 to} n ₄ and n _{6 to} n ₉ adjacent to the macro block n ₅ are stored. Interpolation processing is performed so that the average value is newly set as data of the macroblock n ₅ . The control unit 90 can perform such interpolation processing on macroblocks having all abnormal values and create freeze image data.

  If it is determined in S402 that the service is not a fixed service, it is determined whether the currently output data is video and audio for a mobile service (S406).

  If it is determined in S406 that the service is a mobile service, it is determined whether the video and audio for the fixed service have been received well enough to return to the fixed service (S407). If it is determined, the control unit 90 controls the audio switching processing unit 70 and the video switching processing unit 80 so as to output video and audio for fixed services (S413).

  If it is determined in S407 that the reception is not good enough to return to the fixed service, the process proceeds to S404, and the steps after S404 are repeated.

  If it is determined in S406 that the service is not a mobile service (when it is determined that the output is analog TV output), is the video and audio for the mobile service received well enough to return to the mobile service? If it is determined that the reception is satisfactory, the process proceeds to S407. If it is determined that the reception is not good enough to return to the mobile service, the process proceeds to S405. Repeat the following steps:

  If it is determined in S401 that the broadcast is not simultaneous broadcasting, the control unit 90 determines whether the currently output data is video and audio for a fixed service (S409).

  If it is determined in S409 that the service is a fixed service, it is determined whether video and audio for the fixed service are received well (S410). If it is determined that the service is good, The control unit 90 controls the audio switching processing unit 70 and the video switching processing unit 80 so as to output video and audio for fixed services (S413).

  If it is determined in S410 that the fixed service is not received well, the process proceeds to S415.

  If it is determined in S410 that the service is not a fixed service (if it is determined that the service is in a frozen state), whether or not the video and audio for the fixed service are received well enough to return to the fixed service. (S411), if it is determined that the condition is good, the control unit 90 causes the audio switching processing unit 70 and the video switching processing unit 80 to output video and audio for a fixed service. Control is performed (S413).

  If it is determined in S411 that the reception is not good enough to return to the fixed service, the process proceeds to S415.

  In this way, the control unit 90 switches between the fixed service, the mobile service, and the analog TV, for example, according to the processing flow of FIG. 4, and outputs them from the in-vehicle speaker 170 and the in-vehicle display unit 180.

  FIG. 5 is a diagram illustrating the switching timing between the fixed service and the mobile service in the digital data receiver according to the present invention.

FIG. 5A illustrates a case where the electric field strength signal S ₁ from the first tuner unit 11 and the electric field strength signal S ₂ from the second tuner unit 21 are combined, and the first threshold value is compared with the first threshold value or less. In this case, the S level down signal (S level D) is an H level output. FIG. 5B shows a combination of the electric field strength signal S ₁ from the first tuner unit 11 and the electric field strength signal S ₂ from the second tuner unit 21, and compares the second threshold value to the second threshold value. This is an S level up signal (S level U) that becomes an H level output when the value is equal to or less than the threshold value. Here, the second threshold is set higher than the first threshold. Therefore, when the reception situation deteriorates and the electric field strength signals of both tuner units 11 and 21 decrease, the S level U first becomes the H level, and then the S level D becomes the H level. In the digital data receiver, when the S level D is L level, the fixed service output is set to be able to be output satisfactorily. It was set to be ready for output. That is, the conditions for switching from the mobile service to the fixed service are set more strictly than the conditions for switching from the fixed service to the mobile service. This is to prevent frequent switching between the fixed service and the mobile service.

Error correction signal shown in FIG. 5 (c), an uncorrectable error signal RS ₂ AND output from the uncorrectable error signal RS ₁ and the 2OFDM demodulator 22 from the 1OFDM demodulator 12, when the H-level It shows that an uncorrectable error has occurred in both the first and second OFDM demodulation units 12 and 22.

  The TS error signal shown in FIG. 5 (d) is a signal output from the demultiplexing unit 41, and is H when a TS packet including an error occurs in a TS packet related to video and audio for a fixed service. This is a level signal. The demultiplexing unit 41 counts packets in which TS error bits of TS packets related to video and audio for fixed services indicate an abnormality, and the abnormality of TS error bits counted per 20000 TS packets is 200 or more. , TS error signal (fixed) is set to H level. Note that the error rate (1% or more) of the TS packet that sets the TS error signal (fixed) to the H level is an example, and an optimum value can be selected. Similarly, the TS error signal shown in FIG. 5 (e) is a signal output from the demultiplexing unit 41, and TS packets containing errors occur in a predetermined percentage or more in TS packets related to video and audio for mobile services. In this case, the signal becomes H level. Also here, the error rate of the TS packet that sets the TS error signal (fixed) to the H level is set to 1% or more.

  Normally, the S level D first becomes H level due to the deterioration of the reception state, and the uncorrectable error signal becomes H level by demodulating the received data received after the reception state deteriorates. Since there is a high possibility that many TS error bits are abnormal in the TS packet, the TS error signal (fixed) becomes H after that.

  As shown in FIG. 5 (f), when the S level D signal first becomes H level (A in the figure), the control unit 90 starts switching from the fixed service to the mobile service, and then the reception state When the TS error signal (mobile phone) is at the L level (the reception status of the mobile service is good) and the S level H signal is at the L level (D in the figure), the mobile service is returned to the fixed service. Start switching for

  In addition, if the switching between the fixed service and the portable service frequently occurs or the reliability is not enough only by the setting of the S level D signal and the S level H signal, the switching from the switching to the portable service is resumed. It is also possible to control so that the period S up to is not within a predetermined period (for example, 10 seconds).

  Furthermore, when the S level H signal is L level, the uncorrectable error signal is L level, the TS error signal (fixed) is L level, and the TS error signal (mobile) is L level (F in the figure), it is carried for the first time. You may control to start the return from a service to a fixed service.

  Furthermore, the error rate of the TS packet for the TS error signal to become the H level and the error rate for the L level to be set can be set differently.

In the example shown in FIG. 5, field strength signals S ₁ and S ₂ , error uncorrectable error signals RS ₁ and RS ₂ , TS error signal (fixed), and TS error signal are used for switching control between the fixed service and the mobile service. (Mobile) was used as the state detection signal. However, the reception status of the fixed service and the mobile service can also be detected using the CRC code included in the TS packet. In that case, as in the case of the TS error signal described above, an abnormal state TS packet is detected using a CRC code, and the error rate of the TS packet is calculated and received when the error rate exceeds a predetermined error rate. What is necessary is just to judge that a state is bad.

  In addition, in order to control switching between a fixed service and a mobile service, the fixed service uses a NULL packet (one type of TS packet) having a NULL code in the data part, in order to use it for monitoring a broadcast radio wave. It is also possible to detect the reception status of the mobile service. A NULL packet is detected using PID, the data part is decoded, and if all are NULL codes, it is determined that there is no abnormality, and if anything other than a NULL code is detected, it is determined that there is an abnormality.

  Further, the motion vector amount error rate signals output from the first and second video decoders 53 and 54 can be used for switching control between the fixed service and the mobile service. The motion vector amount error rate signal is a signal indicating what percentage of the macroblock (see FIG. 3) has an abnormal value. The motion vector amount is two-dimensional data indicating the amount of deviation on the reference screen (the playback screen encoded at the previous time and decoded for use at the next timing). If it is greatly disturbed, it indicates a large movement state. Therefore, when there are many macroblocks in which one motion vector amount indicates an abnormal value (when it is larger than a preset value) in one frame, a lot of noise is generated or the video is greatly disturbed. Therefore, it can be determined that the reception state is bad. Therefore, a threshold relating to the motion vector amount error rate signal is set and more than that (for example, when 30% or more of macroblocks constituting one screen of a fixed service video shows an abnormal value in the motion vector amount) In addition, control can be performed to switch from the fixed service to the mobile service. The motion vector amount error rate signal is a state detection signal related to video, but since the audio reception status often corresponds to the video reception status, audio switching processing is performed using the motion vector amount error rate signal. There is no big problem.

  Furthermore, the evaluation image can be used for switching control between the fixed service and the mobile service. The evaluation image is a still image that is transmitted regularly or irregularly by a broadcasting station in order to monitor services due to weather or the like. In the digital data receiver 100, the evaluation image data for the fixed service is decoded and temporarily stored in the HDD 60 or the RAM 91 via the data decoder 55, and the control unit 90 stores the original data stored in the HDD 60 or the ROM 92 in advance. Image evaluation is performed between images. When the degradation level (dB) of the received image for evaluation for a fixed service is large by image evaluation, switching control from the fixed service to the mobile service is performed. Image evaluation can be performed based on a PSNR (Peak Signal to Noise Ration) estimation method or the like.

  Furthermore, the same data broadcasting data that can be repeatedly received by carousel broadcasting can be used for switching control between the fixed service and the portable service. For example, when data with the same contents such as EPG data can be received repeatedly, the data received last time is temporarily stored, the data received this time is compared with the data received last time, and the data received this time When the deterioration level (dB) is large, it is possible to perform control so as to perform switching control from the fixed service to the mobile service.

  Furthermore, the audio data decoded by the audio decoder can be used for switching control between the fixed service and the mobile service. Since audio is a continuous wave, the decoded digital audio data should normally have continuity. Therefore, when the continuity of the decoded digital audio data is interrupted by the audio prediction process or the like, it can be determined that the reception state is defective. Therefore, when the speech prediction processing is performed on the speech data for the fixed service from the first speech decoder and the continuity of the speech data is interrupted, the first or second speech decoder 51, 52 receives the speech prediction error signal. , And the control unit 90 can perform control to switch from the fixed service to the mobile service based on the speech prediction error signal. The audio prediction error signal is a state detection signal related to audio, but the video reception status often corresponds to the audio reception status, so even if video switching processing is performed using audio data, it is a big problem. It will not be.

The timing and conditions for switching control from the fixed service to the mobile service have been described with reference to FIG. However, using the above-described state detection signal (for example, the electric field strength signal S ₃ for the reception state of the analog TV output), the switching control from the portable service to the analog TV output and the return from the portable service to the fixed service are performed. Switching control and switching control for returning from the analog TV output to the portable service can be performed. In that case, by setting the switching conditions for each switching control, it is possible to prevent frequent switching or switching to a service whose reception state has not been restored. it can.

  FIG. 6 is a diagram showing video switching control in the digital data receiver according to the present invention.

  FIG. 6A is a schematic diagram of fixed service (MPEG2 system) video frames output from the first video decoder 53, and frames N, N + 1, N + 2 to N + 16 of SD size (720 × 480 pixels). Indicates a situation in which are sequentially output. Similarly, FIG. 6B is a diagram schematically showing a mobile service (H.264 or MPEG4 system) video frame output from the second video decoder 54, and is a QVGA size (320 × 240 pixels) frame. The situation where M-16 to M-2, M-1, and M are sequentially output is shown. It is assumed that the fixed service video frame M + 16 and the mobile service video frame M-16 are substantially the same video (correlation is equal). As described with reference to FIG. 5, the service switching is determined by the S level D signal, and the decoded video data is output from the video decoder one after another. It is assumed that it does not coincide with the video frame N in FIG.

  FIG. 6C shows the timing of service switching described in FIG. 5 and shows that switching from the fixed service to the mobile service is started at the point A in the figure.

  FIG. 6D schematically shows a video frame displayed on the in-vehicle display unit 180 (800 × 640 pixels) by the video switching process. As described above, the video size for fixed services (SD, HD and 720P), the video size for mobile services (QCIF, QVGA and 16: 9), and the display size of the in-vehicle display unit 180 are unified. Therefore, the scaling processing unit 81 performs enlargement and reduction so as to match the size of the in-vehicle display unit 180. In addition, the on-vehicle display unit 180 displays video frames at a rate of 16 frames per second.

As shown in FIG. 6D, the video frame 600 for the fixed service is displayed until the time A when the switching process is started, but during the time A to G (fade-in period B ₂ ), the fixed service is displayed. Video frames 601 to 616 obtained by blending the video frame for the screen and the all-black screen are displayed. Video frames 601 to 616 are video frames obtained by blending video frames N + 1 to N + 16 for fixed services and an all-black screen. The blend ratio between the fixed service and the all black screen is 15/16: 1/16 for the video frame 601 and 1/16: 15/16 (almost all black) for the video frame 601. The blend ratio was controlled to change every 1/16 between frames.

After that, during a period from time G to H (mute period B ₃ ), a predetermined number of telops 620 are displayed for several seconds (16 frames per second). The telop displays that the fixed service has been switched to the mobile service.

After that, during time HI (fade-out period B ₃ ), video frames 651 to 666 in which video frames for mobile services are blended with an all-black screen are displayed. The video frames 651 to 666 are video frames obtained by blending video frames M-16 to M-1 for mobile services and an all-black screen. The blend ratio between the mobile service and the all black screen is 1/16: 15/16 (almost all black) for the video frame 651 and 15/16: 1/16 for the video frame 666. The blend ratio was controlled to change every 1/16 between frames.

Therefore, in the video switching process, the video for the fixed service is faded out from the start of the switching process (period B ₂ ), and then the display indicating that the switching has been performed is performed (period B ₃ ), and the video for the mobile service is faded in. Since the switching process is completed (period B ₄ ), the switching process period B ₁ is necessary as a whole.

In Figure 6, has been fixed switching processing period B _1, in accordance with switching process period B ₄ to the genre of the program, it is preferable to change. For example, for a program such as a sports program where the video content changes drastically, the switching process period B1 is set short (about ₁ to 2 seconds), and for a program such as a news or talk program where the video content changes slowly, the switching process is performed. longer period _{B 1} (about 5 to 10 seconds) is preferably set. In other words, the control unit 90 discriminates the information of the genre of the program from the EPG data to be received from the data decoder 55, it is possible to perform control so as to change the switching process period B _1.

  In addition, in FIG. 6, the case where video frames are displayed at a rate of 16 frames per second (frame switching every 1/16 second) has been described as an example, but the switching timing of video frames is 1/16 seconds. It is not limited. Therefore, for example, the video frame can be switched every 1/32 seconds.

Further, in FIG. 6, in the fade-in period B ₁ and the fade-out period B ₃ , the video frames are switched every 1/16 seconds, and the blend ratio is changed every 1/16 minutes for each switching. The rate of change in timing and blend ratio is not limited to this. Thus, for example, fade in in period B _2, video frames 10:90 blend ratio of the video frame and the all black screen for fixed services to display 1/16 sec, video frames in which the blending ratio 20:80 May be displayed for 2/16 seconds, a video frame with a blend ratio of 30:70 may be displayed for 3/16 seconds, and the display time may be changed according to the friend ratio.

Furthermore, in FIG. 6, the entire video frame for fixed services and the entire video frame for mobile services are blended with the all-black screen, but only a part of the video frame is blended, and the other parts are instantly You may control to switch. FIG. 7 shows an image display area 700 of 800 (X ₁ ) × 480 (Y ₁ ) pixels of the in-vehicle display unit 180. Here, for example, only the attention image area 701 of 600 (X ₂ ) × 300 (Y ₂ ) pixels of the in-vehicle display unit 180 is faded out from the video frame for fixed service, and the telop of the telop as described with reference to FIG. Switching processing such as display and fade-in from a mobile service is performed, and the peripheral video area 702 other than the target video area is immediately changed from a fixed service video frame to a mobile service video frame according to the start of the switching process. It may be controlled so as to be switched to a portion. Note that it is preferable that the user can freely set the target video area using the remote controller 190 or the like.

Furthermore, although FIG. 7 illustrates switching from a video frame for fixed services to a video frame for mobile services, the same applies to switching processing for returning from a video frame for mobile services to a video frame for fixed services. A simple switching processing method can be employed. In that case, the switching process period B ₁ and blend ratio, and switching from the fixed service to a mobile service, in the switching from the mobile service to the fixed service, it is preferable to be able to set individually freely. A similar switching processing method can also be adopted for switching processing between the mobile service and the analog TV output.

  FIG. 8 is a diagram for explaining another example of video switching control in the digital data receiver according to the present invention.

  In FIG. 6, the video is controlled so that the entire video is switched from the video for the fixed service to the video for the mobile service. However, in the example shown in FIG. 8, the control unit 90 generates an error in the video for the fixed service. Control is performed so that only the portion is replaced with video for mobile service in units of pixels.

  FIG. 8A shows a video frame 800 for a fixed service in which an error has occurred. In the figure, micro blocks corresponding to pixels 801 to 805 are determined to be abnormal and are displayed in green in the video frame 800. If the reception state is further deteriorated, many error portions are generated in the entire video frame, and viewing cannot be performed. Therefore, in the example of FIG. 8, when the service switching start shown in FIG. 6C is instructed, a pixel in which an error has occurred in the video frame for the fixed service is determined as the corresponding video frame for the mobile service. Processing is performed so as to replace the part.

  FIG. 8B shows a video frame 810 for a mobile service corresponding to the video frame 800 shown in FIG. In FIG. 8B, locations corresponding to the error occurrence locations 801 to 805 in FIG.

  FIG. 8C shows a video frame in which the error locations 801 to 815 of the video frame 800 in which an error has occurred are replaced with corresponding locations 811 to 815 in the video frame 810 of FIG. .

  As described above, the control unit 90 generates a good video frame by replacing the video frame for the fixed service with the corresponding part of the video frame for the mobile service and displays the video frame on the in-vehicle display unit 180 for each frame. Control can be performed. The control unit can detect an error part in a fixed service video frame from a motion vector amount indicating an abnormal value. That is, the control unit replaces a pixel (for example, 16 × 16 pixels) corresponding to a motion vector amount indicating an abnormal value with data of a corresponding pixel of the corresponding video frame for mobile service in the video frame for fixed service. Control as follows. As described above, since the video frame size for the fixed service, the video frame size for the mobile service, and the size of the image display area of the in-vehicle display unit are different, the pixel replacement is performed by the scaling processing unit 81. It is preferable to perform after combining.

  In the example of FIG. 8, control is performed so as to replace the portion where the error of the video frame for the fixed service is generated by using the video frame of the mobile service, but an error occurs in the video frame for the same fixed service. It is also possible to store the past video frames that have not been performed and perform control so as to replace the error occurrence location using the stored video frames.

  FIG. 9 is a diagram showing audio switching control in the digital data receiver according to the present invention.

  FIG. 9A shows audio data for fixed services output from the first audio decoder 51, audio data for mobile services output from the second audio decoder 52, and output from the analog TV tuner unit 30. An example of switching timing between the audio output of the analog TV and the mute output from the mute output unit built in the audio switching processing unit 70 is shown. That is, the switching from the fixed service to the portable service is started at time A in the figure, the switching from the portable service to the analog TV output is started at time J in the figure, and the analog TV output is muted at time K in the figure. Switching to output is started, switching from mute output to analog TV output is started at time L in the figure, switching from analog TV output to portable service is started at time M in the figure, and time in the figure At N, switching from the mobile service output to the fixed service is started. The switching timing shown in FIG. 9A is determined by the control unit 90 using the reception state detection signal described with reference to FIG.

  FIG. 9B is a diagram showing the sound level of the sound data from each service or the like. The voice switching process shown in FIG. 9B is performed by the control unit 90 controlling the voice switching processing unit 70. As shown in FIG. 9B, the control unit 90 performs control to output voice data for fixed service from the in-vehicle speaker 170 until time A when the switching process is started ( 901).

As shown in FIG. 9 (b), the control unit 90, the audio level of the audio data of a fixed service during the fade-out period S ₁₁ from the time A to control so as to decrease gradually to 0 (902), then, during the mute period S ₁₂ is controlled to perform the mute output (903) performs control so as to raise the subsequent audio level of the audio data for mobile services during the fade-in period S ₁₃ from 0 to a predetermined level ( 904). That is, during the switching process period S _1, completes the switching processing from the fixed service to a mobile service. After that, voice data for mobile service is output (905).

The control unit 90, the audio level of the audio data of the mobile services during the fade-out period S ₂₁ from time J to control so as to decrease gradually to 0 (906), then, during the mute period S ₂₂ is muted controlled so as to perform output (907), then performs control so as to increase from 0 to speech level of the analog TV output during the fade-in period S ₂₃ to a predetermined level (908). That is, during the switching process period S _2, completes the switching process from the mobile service to the analog TV output. Thereafter, the analog TV output sound is output (909).

Further, the control unit 90, the speech level of the analog TV output control so as to reduce gradually to 0 from time K during the fade-out period (= switching processing period) S ₃ (910), then performs a muting output Control is performed as follows (911).

Further, the control unit 90, the speech level of the analog TV output control so as to increase gradually from zero to a predetermined level from the time L during the fade-in period (= switching processing period) S ₄ (912), then, The sound of analog TV output is output (913).

Further, the control unit 90, the audio level of the audio data of the mobile services during the fade-out period S ₅₁ from time M control to lower gradually to 0 (914), then, during the mute period S ₅₂ is muted controlled so as to perform output (915), then performs control so as to raise the sound level of the fixed service during a fade-in period S ₅₃ from 0 to a predetermined level (916). That is, during the switching process period S _5, completes the switching process to the fixed service from the mobile service. Thereafter, the voice data for the fixed service is output (917).

In FIG. 9, the fade-out periods S ₁₁ , S ₂₁ , S ₃ and S ₅₁ and the fade-in periods S ₁₃ , S ₂₃ , S ₄ and S ₅₃ are set to the same time interval. It is preferable that the setting can be changed or the setting can be changed according to an input operation from the remote controller 190 or the like according to the user's preference. Similarly, in FIG. 9, the mute periods S ₁₂ , S ₂₂ and S ₅₂ are set to the same time interval, but each switching process period can be freely set in advance, or from the remote controller 190 or the like according to the user's preference. It is preferable that the setting can be changed according to the input operation.

Further, switching processing periods S _{1 to} S ₅ , fade-out periods S ₁₁ , S ₂₁ , S ₃ and S ₅₁ , fade-in periods S ₁₃ , S ₂₃ , S ₄ and S ₅₃ , and mute periods S ₁₂ , S ₂₂ and S ₅₂ is preferably changed according to the program genre. For example, the switching process periods S _{1 to} S ₅ are set short (about 10 ms) for a program such as a sports program that changes drastically, and the switching process is performed for a program such as a news program or a talk program that changes slowly. It is preferable to set the periods S _{1 to} S ₅ long (about 200 ms). In sports programs and the like, it is preferable to perform switching processing instantaneously, but popping sound is generated if switching is performed too early, so it is necessary to leave a time interval of at least about 10 ms. In other words, the control unit 90 discriminates the information of the genre of the program from the EPG data to be received from the data decoder 55, it is possible to perform control so as to change the switching process period S ₁ to S _5. Of course, it is also possible to set the switching process periods S _{1 to} S ₅ in synchronization with the switching time interval indicated by the video switching process described with reference to FIG.

  In the example of FIG. 9, as shown in FIG. 9B, the sound level of the sound data for the fixed service, the sound level of the sound data for the mobile service, and the sound level of the analog TV output are in a steady state. Then, it set so that it might become the same level. However, the audio level is not adjusted in advance between the services while being transmitted from the broadcasting station. Therefore, it is preferable to measure the sound level of each service or the like in advance and set a parameter for adjusting the sound level of each service or the like as a default value. If the sound level adjustment is not performed, a difference occurs in the volume level output from the vehicle-mounted speaker after the switching process, which gives the user unpleasant feeling. Therefore, for example, the volume level of voice data for mobile services is set to -10% with respect to the volume level of voice data for fixed services, and the volume level of analog TV output is set to the volume level of voice data for fixed services. Is preferably set to -15%. Furthermore, it is more preferable that the adjustment value is individually provided for each channel.

  Further, in FIG. 9, when the reception state of the fixed service deteriorates, the switching control is performed so as to switch to the mobile service. However, if the reception state deteriorates without switching to the mobile service at a time, it is possible to first control to change the sampling rate of the voice data for the fixed service. The sampling rate of voice data for fixed services is 48 ksamples / second (full sampling rate), and the sampling rate of voice data for mobile services is 24 ksamples / second. Therefore, it is possible to thin out the voice data for fixed services and output the sampling rate corresponding to half of 24 ksamples / second (half sampling rate). That is, when the reception state deteriorates, the fixed service full sampling rate output is switched to the fixed service half sampling rate output, and when the reception state deteriorates, the fixed service half sampling rate output is switched to the portable service. It is possible to perform control. Note that the sampling rate is changed by the first audio decoder 51 or the audio switching processing unit 70 in accordance with a control instruction from the control unit 90.

  By the way, while the sampling rate of CD is 44.1k samples / second, the sampling rate of voice data for fixed services is 48k samples / second, and the sampling rate of voice data for mobile services is 24k samples / second. Seconds. Therefore, when the user switches the output from the CD player to the digital TV of the digital data receiver according to the present invention, the user may notice a change in sound quality. Therefore, it is preferable to perform control so that the sampling rate of the audio data of all the sources is changed to a predetermined sampling rate and then output from the in-vehicle speaker 170. For example, it is preferable to change the sampling rate of audio data for CDs, fixed services, and audio data for mobile services to 32 ksamples / second. Note that the sampling rate is changed by the voice switching processing unit 70 in accordance with a control instruction from the control unit 90.

  Further, in FIG. 9, a fade-out, fade-in, or mute period is provided in the service switching process period, and control is performed so that the switching of the audio data is smoothly shifted. However, the audio output during the switching process period can also be configured to be output to the in-vehicle speaker 170 via a low-pass filter. This is for removing high-frequency noise that may occur at the time of switching. In addition, without providing fade-out, fade-in, and mute periods in the service switching process period, switching between services is performed immediately, and the audio output during the switching process period is simply mounted on-vehicle via a low-pass filter. It can also be configured to output to the speaker 170.

Figure 10 is a diagram illustrating a method of adjusting the sound level in the fade-out period S ₁₁ in FIG.

In the fade-out period S ₁₁ shown in FIG. 9, was linearly reduced sound level of the audio data of a fixed-friendly service to fade as 902 in FIG. 10. However, it is also possible to set the audio level reduction rate in a fade-out period in a curve. By setting the curve, it is possible to give the user an impression that the service is switched more smoothly during the switching process period. One method of setting the audio level reduction rate during the fade-out period in a curve is to set a fade-out start point P ₁ , end point P ₂ and intermediate point P ₃ , and according to a cubic curve passing through three points. The rate of decrease of the sound level may be controlled. As shown in FIG. 10, it is possible according to the setting of the intermediate point _{P 3,} to set the reduction rate to the 1002 or 1003. The setting of the intermediate point P _3, it is further preferred that the user to perform the input operation from the remote controller 190 or the like.

  Although FIG. 10 illustrates the fade-out period from the fixed service to the mobile service as an example, it is preferable that other fade-out periods and fade-in periods can be set in the same manner.

Figure 11 is a diagram showing another method of adjusting the sound level in the fade-out period S ₁₁ in FIG.

Fade-out period S ₁₁ shown in Figure 9, was fixed in advance. However, the fade-out period S ₁₁ based on past history information, it is also possible to allow automatically changed.

For example, if the fade-out period S ₁₁ is set to 200ms in switching processing from the fixed service to a mobile service, and a buffer memory that can be first audio decoder stores the audio data for the fixed services only 100ms min Shall. For example, the first audio decoder 51 does not perform decoding from the time when switching from the fixed service to the portable service is started by the S level D signal (see FIG. 5A), and the audio stored in the buffer memory. it is also possible to perform the output of the audio data in the fade-out period by using the data only (if so, fade-out period S ₁₁ becomes 100ms buffer min at most). However, at the time when switching from the fixed service to the mobile service is started, the first audio decoder is likely to decode data at a time point earlier than the poorly received data that caused the S level D signal. . Therefore, even after switching from the fixed service to the mobile service is started, the TS packet is monitored and the decoding is continued until the TS packet error is detected, and the data stored in the buffer memory is detected after the TS packet error is detected. Can be controlled to output.

However, when such control is performed, it is not certain how long data output can be continued from the time when switching from the fixed service to the portable service is started by the S level D signal (see FIG. 5A). Absent. Therefore, the control unit 90 can output the voice data for the fixed service from the start of switching every time switching from the fixed service to the portable service occurs (decoding possible period: for example, FIG. 5). stored in ROM92 such as 501 history information period) of (d), the average value of the stored decoded period, then automatically controlled to match the fade-out period S ₁₁ at the time of switching control for generating It is preferable. It is more preferable to store the average value, the longest value, and the shortest value of the decodable period as the history information.

That is, when the first audio decoder has a buffer memory for 100 ms and the fade-out period is initially set to 200 ms, according to the control method described above, the control unit 90 automatically performs the operation between 100 ms and 200 ms. A fade-out period S ₁₁ (see 1101 in FIG. 11) is set.

  Data synchronization between the fixed service and the mobile service will be described below.

  As described above, the video data and audio data of the fixed service and the mobile service are divided into discrete TS packets and received. Each decoder 50 reassembles data from these TS packets to create video data and audio data. When packetizing video data and audio data for fixed service and mobile service, as described above, PTS (presentation time information) is added to PH (header part) (see FIGS. 2B and 2C). ). PTS indicates the time output from the speaker for audio data, and the time displayed on the display unit for video data. Therefore, by using PTS, it is possible to synchronize video data and audio data for fixed services, and to synchronize video data and audio data for mobile services. By the way, although PTS does not guarantee the synchronization between the fixed service and the mobile service, it is highly possible that the PTS indicates almost the same time. Therefore, in the digital data receiver 100 according to the present invention, control is performed so that the fixed service and the mobile service are synchronized using the PTS in the case of switching processing between services.

  For example, in FIG. 6D, the same PTS as the PTS added to the PH of the fixed service packet including the data constituting the video frame 616 for the fixed service is included in the mobile service packet added to the PH. The video frame 651 for the mobile service may be configured from the data to be stored. Similarly, for example, in FIG. 9B, the same PTS as the PTS added to the PH of the fixed service packet including the data constituting the voice data 901 and 902 for the fixed service is added to the PH. The audio data 903 and 904 for the mobile service may be configured from the data included in the mobile service packet. In this way, by using the PTS, it is possible to prevent video and audio from being shifted due to switching when performing switching processing between the fixed service and the mobile service.

  In the above-described example, the fixed service and the mobile service are synchronized using the PTS, but the PCR (program time reference value) and the DTS (data added when the data is decrypted) included in the PH described above. Decoding time information) can also be used. This is because PCR and DTS also indicate the system time of data corresponding to them. Therefore, similarly to the PTS, the control unit 90 can prevent video and audio from being shifted due to switching when performing switching processing between the fixed service and the mobile service using PCR or DTS. it can. Furthermore, it is possible to average data of three values of PTS, PCR, and DTS, and specify data for mobile services that are synchronized with data for fixed services. By averaging and using the three parameters, synchronization can be achieved more accurately.

  In the above-described example, the fixed service and the mobile service are synchronized using the PTS. However, using the motion vector amount in units of frames, the video frame for the fixed service and the video frame for the mobile service are Can be synchronized. The amount of motion vector for each frame can be obtained by calculation in the first and second video decoders 53 and 54 based on the value of the motion vector amount of all macroblocks included in the target frame. This is because video frames having the same amount of motion vector for each frame are highly likely to be frames having the same content. Therefore, the control unit 90 can prevent the video frame from being shifted due to the switching when the switching process between the fixed service and the mobile service is performed using the motion vector amount in units of frames.

  Similarly to the calculation of the motion vector amount, it is also possible to perform control so as to search for synchronized data using an operation such as a correlation function. In the above-described example, it is determined that data having the same PTS, PCR, and DTS values are synchronized data. However, if synchronized data can be determined by calculation, the PTS, PCR of these data can be determined. It is also possible to create and re-add the values of PTS, PCR and DTS related to any service so that the values of DTS and DTS are the same. For example, even when a shift in the DTS value between video frames synchronized with a fixed service video frame and a mobile service video frame can be detected by calculating a motion vector amount, synchronization is performed by switching processing. For this purpose, it is necessary to store a predetermined amount of video frames for fixed services and video frames for mobile services in the buffer memory. On the other hand, if the preset 50 is set so that the fixed service and the mobile service have the same DTS value between the video frames that are synchronized by producing the DTS value in the decoder unit 50, the video frame for the fixed service is used. The amount of buffer memory for storing video frames for mobile services can be made very small.

  FIG. 12 shows a display control flow using the HDD 60.

  The above-described data switching process between the fixed service, the mobile service, and the analog TV output is performed by a buffer memory having an appropriate capacity for each of the decoders 51 to 54, the audio switching processing unit 70, the video switching processing unit 80, the drawing processing unit 82, and the like. It can respond by providing. Therefore, the HDD 60 is not always necessary. However, more comfortable display control can be performed by temporarily storing the data output from the decoders 51 to 54 in the HDD and displaying the stored data.

  First, the control unit 90 temporarily stores data from the decoders 51 to 54 in the HDD 60 (S1201).

  Next, the control unit 90 stores the service switching information as shown in FIG. 5 in the HDD 60 (S1202).

  Next, the control unit 90 selects the optimum service from the data temporarily stored in S1201 according to the flow shown in FIG. 4 based on the service switching information stored in S1202. Further, only the selected data is combined to create synthesized data for each video data and audio data (S1203).

  Next, the control unit 90 performs predetermined control to output the audio data created in S1203 to the in-vehicle speaker 170 and the video data to the in-vehicle display unit 180.

  Data output to the in-vehicle speaker 170 and the in-vehicle display unit 180 is temporarily stored in the HDD 60, and can be sent from the actual reception time for the period of the synthesis process. However, since the fixed service, mobile service, and analog TV output temporarily stored in S1201 can be used, the video switching process shown in FIG. 6 and the voice switching process shown in FIG. 9 can be performed. It is possible to obtain optimal audio and video data.

  FIG. 13 shows a recording control flow using the HDD 60.

  By having the HDD 60, for example, when a TV recording reservation is made at the time of going to work in the morning by an operation input using the remote controller 190 or the like to the digital data receiver 100, the apparatus performs a TV recording and a predetermined recording in the daytime. It is possible to perform processing so that the complete TV recording data is stored when the user goes home at night.

  First, the control unit 90 accepts a recording reservation by an operation input using a remote controller or the like from the user (S1301).

  Next, the control unit 90 tunes the receiving units 10 and 20 according to the recording reservation, and stores the data from the decoders 51 to 54 in the HDD 60 for the recording time reserved for recording (S1302).

  Next, the control unit 90 stores the service switching state as shown in FIG. 5 in the HDD 60 (S1303).

  Next, the control unit 90 selects an optimum service from the data stored in S1302 according to the flow shown in FIG. 4 based on the service switching information stored in S1303. Further, only the selected data is combined to create composite data for each video data and audio data (S1304).

  Next, the control unit 90 saves the composite data created in S1304 in the HDD 60 (S1305), and erases the data stored in S1301 (S1306).

  The composition of the composite data stored in the HDD 60 does not require real-time characteristics, and uses all of the stored fixed service, mobile service, and analog TV output, and the video switching process and the diagram shown in FIG. Since the audio switching process shown in FIG. 9 can be performed, optimal audio and video data can be obtained.

  In the flow of FIG. 13, the composite data is created and stored. However, the fixed service, the mobile service, and the analog TV output corresponding to the recording time reserved for recording are all stored in the HDD 60 and each service is reproduced at the time of playback. Control may be performed so that video data and audio data are output while switching between them.

  12 and 13, when the fixed service, the mobile service, and the analog TV output are stored in the HDD 60, the synchronization between the fixed service and the mobile service is detected, and the synchronized data is stored. Control can be performed so as to store the shift amount of the address in the HDD. By performing such control, the process of synchronizing is reduced during reproduction or display.

  FIG. 14 is a diagram for explaining network follow control.

  In Japanese terrestrial digital broadcasting, network follow information indicating which of the assumed channels is broadcasting the same content is transmitted as data being broadcast. Therefore, the control unit 90 can receive the network follow information and perform control so as to construct an optimal reception environment.

  In FIG. 14, it is assumed that the same program is broadcast at a point in time when there is a first broadcast station 1400 (for example, channel 20) and a second broadcast station 1420 (for example, channel 40). An area 1401 is an area where the fixed service and the mobile service related to the channel 20 can be received simultaneously, and an area 1402 is an area where only the mobile service related to the channel 20 can be received. An area 1421 is an area where the fixed service and the mobile service related to the channel 40 can be received simultaneously, and an area 1422 is an area where only the mobile service related to the channel 40 can be received. Further, the area 1410 is an area where the mobile service related to the channel 20 and the mobile service related to the channel 20 can be received simultaneously.

  If a vehicle equipped with the digital data receiver 100 according to the present invention moves from the area 1401 to the area 1421, the first and second receiving units 10 and 20 are tuned to the channel 20 in the area 1401, and the channel As described above, the best video and audio can be output as described above by performing the switching process between the fixed service and the mobile service 20. However, in the area 1410, if it is tuned to the channel 20, only the mobile service related to the channel 20 is received, and if it is tuned to the channel 40, only the mobile service related to the channel 40 is received.

  Therefore, in the digital data receiver 100 according to the present invention, when a vehicle is present in the area 1410, control is performed so that the mobile service related to the channel 20 and the mobile service related to the channel 40 can be received simultaneously.

  Here, in the navigation device 150, network follow map information indicating an area where both the fixed service and the mobile service corresponding to each channel can be received and an area where only the mobile service can be received is created and stored in advance. It shall be. Therefore, the control unit 90 determines whether the vehicle exists in an area where the data of the same program can be received from a plurality of channels based on the current position information of the vehicle, the network follow map information, and the network follow information. Can do.

  If the control unit 90 determines that the vehicle is present in the area 1410 based on the current position information of the vehicle, the network follow map information, and the network follow information, the control unit 90 cancels the diversity method and sends the master reception unit 10 to the channel 20. The slave receiver 20 is tuned to the channel 40. Further, spectrum synthesis by the synthesis unit 40 is stopped. Further, TS packets related to audio data for mobile services related to channel 20 are sent to the first audio decoder 51, TS packets related to video data related to mobile services related to channel 20 are sent to the first video decoder 53, and audio for mobile services related to channel 40 is supplied to the first video decoder 53. The demultiplexing unit 41 is controlled so as to distribute TS packets related to data to the second audio decoder 52 and TS packets related to video data for mobile services related to the channel 40 to the second video decoder 54, respectively. Further, the control unit 90 uses the state detection signal as described above to perform switching processing to data that can be received satisfactorily between the mobile service related to the channel 20 and the mobile service related to the channel 40, and the in-vehicle speaker 170 and the in-vehicle display. Can be output from the unit 180.

  As for the switching process between the mobile service related to the channel 20 and the mobile service related to the channel 40, the video switching process shown in FIG. 6 and the voice switching process shown in FIG. 9 can be applied as they are. Audio and video data can be obtained.

  FIG. 14 describes the case where the vehicle is present in an area where both the mobile service related to the channel 20 and the mobile service related to the channel 40 can be received. However, depending on the position of the broadcasting station, etc., there is a possibility that the vehicle exists in an area where all of the fixed service and the mobile service related to the channel 20 and the fixed service and the mobile service related to the channel 40 can be received. In such a case, control may be performed so that the fixed service related to the channel 20 and the fixed service related to the channel 40 are received and switching control is performed, and four types of data are obtained by having four receiving units. Switching control may be performed so that it can receive and output optimum data.

  FIG. 15 is a block diagram showing an outline of another digital data receiver 102 according to the present invention.

  The difference between the digital data receiver 102 shown in FIG. 15 and the digital data receiver 100 shown in FIG. 1 is that the digital data receiver 102 shown in FIG. 15 does not have the analog tuner unit 30 and the voice switching processing unit 70. Only one audio decoder 56 is provided, and the other is the same. That is, the digital data receiver 102 shown in FIG. 15 is a simplified version of the apparatus shown in FIG.

  The digital data receiver 102 shown in FIG. 15 is configured to always output audio data for mobile services. This is because there is no significant difference between the fixed service and the mobile service in the audio data compared to the video data. Therefore, for voice data, switching control between the fixed service and the mobile service is not performed.

  On the other hand, the digital data receiver 102 shown in FIG. 15 performs switching control between the fixed service and the mobile service for the video data. The switching control between the fixed service and the mobile service is the same as that described for the digital data receiver shown in FIG. Since the analog tuner unit 30 is not provided, there is no switching to analog TV output video, so that when the reception status of video data for mobile services deteriorates, a freeze screen is output. .

  FIG. 16 is a diagram showing an example of a processing flow for switching between the fixed service and the portable service in the digital data receiver according to the present invention shown in FIG.

  Switching in the processing flow shown in FIG. 16 is performed at the same time for video and audio, but switching control can also be performed individually. The switching conditions are the same as those described with reference to FIGS. 6 and 9 for the digital data and receiver shown in FIG. The processing flow shown in FIG. 16 is mainly executed by the control unit 90 of the digital data receiver 102 in cooperation with each element of the digital data receiver 102 according to a program installed in advance. The digital data receiver 102 is assumed to be in a state where the power is turned on and various functions can be operated. Further, it is assumed that the master receiver 10 and the slave receiver 20 are tuned to the same channel.

  The control unit 90 determines whether or not the current time is simultaneous broadcasting (S1601).

  If it is determined in S1601 that the broadcast is simultaneous broadcasting, the control unit 90 determines whether the currently output data is video and audio for a fixed service (S1602).

  If it is determined in S1602 that the service is a fixed service, it is determined whether video and audio for the fixed service are received well (S1603). If it is determined that the service is good, The control unit 90 controls the audio switching processing unit 70 and the video switching processing unit 80 so as to output video and audio for fixed services (S1607).

  If it is determined in S1603 that the fixed service is not received well, it is determined whether the video and audio for the mobile service are received well (S1604), and it is determined that the service is good. If so, the control unit 90 controls the audio switching processing unit 70 and the video switching processing unit 80 so as to output video and audio for the mobile service (S1608).

  If it is determined in S1604 that the mobile service is not received well, the control unit 90 controls the audio switching processing unit 70 to output a mute output (silence) from the in-vehicle speaker 170, and freezes the image. The video switching processing unit 80 is controlled to display the (still image) on the in-vehicle display unit 180 (S1609).

  As in the case of the digital data receiver 100, the freeze image may be created from a fixed service video frame or a mobile service video frame, or by using data stored in the ROM 92 or the like in advance. Also good.

  If it is determined in S1602 that the service is not a fixed service, the data currently being output is a mobile service, so whether or not the video and audio for the fixed service are received well enough to return to the fixed service. (S1605), and if it is determined that it is good, the control unit 90 causes the audio switching processing unit 70 and the video switching processing unit 80 to output video and audio for fixed services. Control is performed (S1607).

  If it is determined in S1605 that the reception is not good enough to return to the fixed service, the process proceeds to S1604, and the steps after S1604 are repeated.

  If it is determined in S1601 that the broadcast is not a simulcast, the control unit 90 receives the video and audio for the fixed service satisfactorily (since the fixed service is automatically selected if it is not a simulcast). In step S1606, if it is determined that the image is good, the control unit 90 outputs the audio switching processing unit 70 and the video switching processing unit so as to output video and audio for the fixed service. 80 is controlled (S1607).

  If it is determined in S1606 that the fixed service is not received well, the control unit 90 controls the audio switching processing unit 70 to output a mute output (silence) from the in-vehicle speaker 170, and freezes the image. The video switching processing unit 80 is controlled to display the (still image) on the in-vehicle display unit 180 (S1609).

  As described above, the control unit 90 switches between the fixed service and the mobile service according to the processing flow of FIG. 16, for example, and outputs them from the in-vehicle speaker 170 and the in-vehicle display unit 180.

  The present invention has been described above by taking the in-vehicle digital data receivers 100 and 102 as an example. However, the digital data receiver according to the present invention is also applicable to portable TVs, TVs mounted on moving means other than cars, and the like. Is possible.

It is a block diagram which shows the outline | summary of the digital data receiver which concerns on this invention. It is a figure which shows the structure of TS and PES. It is a figure which shows the outline of a frame structure. It is a figure which shows the switching process flow. It is a figure which shows a switching timing. It is a figure which shows a video switching process. It is a figure which shows an attention image area. It is a figure which shows the complementation method of an image | video. It is a figure which shows an audio | voice switching process. It is a figure which shows audio | voice level adjustment. It is a figure which shows other audio | voice level adjustment. It is a figure which shows a display flow. It is a figure which shows a recording flow. It is a figure explaining network follow. It is a block diagram which shows the outline | summary of the other digital data receiver which concerns on this invention. It is a figure which shows the switching process flow.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st tuner part 12 1st OFDM demodulation process part 21 2nd tuner part 22 2nd OFDM demodulation process part 30 Analog tuner part 40 Synthesis | combination part 41 Demultiplexing part 51 1st audio | voice decoder 52 2nd audio | voice decoder 53 1st video decoder 54 1st 2 video decoder 55 Data decoding part 60 HDD
70 Audio switching processing unit 80 Video switching processing unit 81 Scaling processing unit 82 Drawing processing unit 83 GDC drawing processing unit 90 Control unit 91 RAM
92 ROM
DESCRIPTION OF SYMBOLS 100 Digital data receiver 110 1st antenna 120 2nd antenna 130 3rd antenna 150 Navigation apparatus 170 Speaker 180 Display part 190 Remote control

Claims (4)

A digital data receiver,
A first receiver;
A second receiving unit;
A first data generation unit;
A second data generation unit;
The first receiving unit and the second receiving unit are tuned to a first channel that performs simulcasting , and data related to the first service of the first channel is output from the first data generating unit and the second data a control from the generator Ru to output data according to the second service of the first channel, a and tunes the first receiver to the first channel and the second receiving unit to broadcast the same program and the first channel by tuning to a second channel are, to output the data according to the second service of the second channel from and to output data according to the second service of the first channel from the first data generation unit and the second data generation unit A control unit that performs switching control, and
A digital data receiver comprising:   The digital data receiver according to claim 1, wherein the control unit performs switching of tuning channels of the first and second receiving units based on network follow information.   2. The digital data receiver according to claim 1, wherein the control unit performs switching of tuning channels of the first and second receiving units based on network follow information, position information of the digital data receiver, and map information. Furthermore, having a switching unit for performing only one of switching processing for outputting the data outputted from the data and the and the second data generation unit that is output from the first data generation unit, according to claim 1 to 3 The digital data receiver according to any one of the above.

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