JP2005347915A - Digital broadcasting receiver and receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital broadcasting receiver with a built-in storage device, which is capable of performing reproduction of excellent quality equivalent to that in a recording mode in the case when a traveling body such as a vehicle receives digital broadcasting, records the digital broadcasting in the storage device, and reproduces the digital broadcasting. <P>SOLUTION: This digital broadcasting receiver records entirely or partially data streams of a received/demodulated hierarchical services in a recording medium 11 about the digital broadcasting with two or more hierarchical services within one and the same transmission channel and can reproduce the record data streams recorded in the recording medium 11 comprises: a recording means 10 for adding error information by which the existence/absence of an error in a data stream can be determined to a data stream and recording the error information in the recording medium 11; and a reproducing means 12 for switching to the more appropriate hierarchical service depending on the number of errors in the added error information being equal to or more than a prescribed number or less than the prescribed number and reproducing the record data streams. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital broadcast receiving apparatus and method capable of recording a broadcast program, and more particularly, to a digital broadcast receiving apparatus with a built-in recording apparatus for a moving body that can record the broadcast program by a moving body such as an automobile.

  In recent years, the transition from the analog system of TV broadcasting to the digital system has been promoted worldwide. Already in Japan, digital CS broadcasting and BS broadcasting have started, and terrestrial digital broadcasting has also started in some areas. The feature of digital terrestrial broadcasting is that OFDM (Orthogonal Frequency Division Multiplex) is used as the transmission method, and it is possible to realize not only fixed reception but also mobile and mobile reception, such as hierarchical transmission up to 3 layers. That is. By using hierarchical transmission, broadcasting for mobile reception (strong hierarchy) and fixed reception (weak hierarchy) can be synchronized with each other (for example, see Non-Patent Document 1). A technique for receiving a broadcast using such hierarchical transmission is disclosed (for example, see Patent Document 1).

Also, against the background of the low price and large capacity of hard disk drives (HDDs), digital broadcasting is recorded in MPEG2-TS (Moving Picture Experts Group 2-Transport Stream) format with the built-in HDD in the digital broadcasting receiver. A technique for reproducing is disclosed (for example, see Patent Document 2).
JP 2000-165766 (5th page, FIG. 1) Japanese Patent Laid-Open No. 2003-9085 (page 17, FIG. 1) ARIB-TR14 1.5 Edition: Digital Terrestrial Television Broadcasting Operation Regulations Vol. 7 Terrestrial Digital Television Broadcasting Operation Regulations (October 16, 2003)

  However, a conventional digital broadcast receiver with a built-in HDD has the following problems. In other words, when a digital broadcast receiver with a built-in HDD is receiving a digital broadcast by a mobile body such as an automobile, the mobile reception is considered, such as the OFDM system and frequency / time interleaving technology being used in the digital terrestrial broadcast. However, the received quality may deteriorate and an error may occur in the received stream. This is because when receiving a digital broadcast by a mobile unit, the reception quality largely fluctuates due to fading, multipath, or C / N degradation, and error correction becomes impossible when the reception quality deteriorates significantly. An error occurs in the received stream.

  As described above, when a broadcast using hierarchical transmission is received in a state where the reception quality is greatly deteriorated, good reception is possible by switching from the weak layer to the strong layer. For example, in Patent Document 1, the switching timing is detected by detecting the temporal fluctuation amount of the input signal characteristic in the front end unit such as electric field strength, C / N value, or BER (Bit Error Rate). The reception quality of the input signal is determined, and the optimum reception layer is switched. In this way, when receiving a terrestrial digital broadcast that is hierarchically transmitted by a mobile body such as an automobile, it is possible to reproduce and display video / audio with good reception quality.

  However, when the received stream is recorded on the HDD and played back in the conventional receiver, for example, a weak layer and a strong layer stream are recorded at the same time. Since the timing of switching the hierarchy in the deteriorated state is unknown, good reproduction / display cannot be performed.

  As described above, in the conventional receiver, the hierarchical switching timing is obtained by using the detection result of the temporal fluctuation amount of the input signal characteristic in the front end unit. That is, the input signal characteristics are detected by measuring the electric field strength, C / N value, BER (error rate), or the like of the input signal at the front end. However, the stream recorded in the HDD is the output of the front end unit, specifically, an MPEG-TS stream. By reproducing this stream, the electric field strength, C / N value, BER (error rate) or the like cannot be measured as in the conventional case. As a result, the timing for switching the hierarchy becomes unknown, and good reproduction / display cannot be performed.

  The present invention has been made in view of such a situation. When a digital broadcast is received by a moving body such as an automobile, and recorded and reproduced in a storage device, the accumulation can be performed as well as during recording. It is an object of the present invention to provide an apparatus built-in digital broadcast receiver.

  The present invention is a digital broadcast receiving apparatus devised to achieve the above object, and all or part of a hierarchical service after receiving and demodulating a digital broadcast in which two or more hierarchical services exist in the same transmission channel. In a digital broadcast receiving apparatus capable of recording the data stream of the recording medium on a recording medium and reproducing the recorded data stream recorded on the recording medium, all or part of the data stream of the hierarchical service after receiving / demodulating the digital broadcast Recording means for adding error information to a data stream for recording on the recording medium, and the number of errors in the added error information when reproducing the recording data stream on the recording medium is greater than or less than a predetermined number And a reproducing means for reproducing the recorded data stream by switching to a more appropriate hierarchical service corresponding to It was so.

  In addition, when the playback unit cannot select a more appropriate hierarchical service when switching to a more appropriate hierarchical service based on the management information or the error information at the time of playback of the recording data stream of the recording medium, that effect is indicated. Was displayed on the screen.

  The present invention provides a digital broadcast receiving apparatus devised to achieve the above object, recording a data stream after receiving and demodulating the digital broadcast on a recording medium, and recording the recorded data stream recorded on the recording medium. Recording that can be recorded on a recording medium by adding error information that can be used to determine whether or not there is an error in all or part of the data stream after receiving and demodulating the digital broadcast in a digital broadcast receiver capable of reproduction And a reproducing means for reproducing the recording data stream based on whether the number of errors in the added error information is greater than or less than a predetermined number when reproducing the recording data stream of the recording medium.

  Furthermore, the present invention has error indicator information detection processing means for detecting that the number of errors in the error information is greater than or less than a predetermined number, and displays the presence or absence of errors in the received / demodulated digital broadcast data stream. I did it.

  Further, the present invention is a digital broadcast receiving method devised to achieve the above object, and all or all hierarchical services after receiving and demodulating a digital broadcast in which two or more hierarchical services exist in the same transmission channel. A digital broadcast receiving method for recording a part of a data stream on a recording medium and reproducing the recorded data stream recorded on the recording medium, wherein all or part of the data stream of the hierarchical service after receiving / demodulating the digital broadcast Adding error information that can be used to determine whether or not there is an error to a data stream and recording it on a recording medium, and at the time of reproducing the recording data stream of the recording medium, the error information of the added error information is greater than or less than a predetermined number And switching to a more appropriate hierarchical service and playing back the recorded data stream. It was.

  Then, the present invention provides a digital broadcast receiving method devised to achieve the above object, and records the data stream after receiving and demodulating the digital broadcast on a recording medium, and the recorded data stream recorded on the recording medium is recorded. A digital broadcast receiving method for reproducing, the step of adding error information that can determine whether or not there is an error in all or part of a data stream after receiving / demodulating the digital broadcast to the data stream and recording it on a recording medium; A step of reproducing the recording data stream based on whether or not the number of errors in the added error information is greater than or less than a predetermined number when reproducing the recording data stream of the recording medium.

  According to the present invention, it is possible to provide a digital broadcast receiving apparatus and method capable of performing good reproduction equivalent to that in recording when a digital broadcast is received by a moving body such as an automobile, recorded in the storage device, and reproduced. .

The best mode for carrying out the present invention will be described.
Embodiments of a digital broadcast receiving apparatus and method according to the present invention will be described below in detail with reference to the drawings. In the following description, “hierarchical transmission” refers to the case where two or more video and / or audio ESs are transmitted in the same transmission channel, and each ES is transmitted after being subjected to different transmission line codes and modulation. Say.

  FIG. 1 is a block diagram illustrating a configuration example of a digital broadcast receiving device to which a storage output device according to an embodiment of the present invention is applied. In FIG. 1, a digital broadcast receiver 1 includes a tuner 2, a transmission path decoding unit 3, a demultiplexing unit (for example, a demultiplexer) 4, a list generation unit 8, a writing unit 10, a recording medium (for example, a hard disk or a memory or an optical disk) 11, A reading unit 12, a list analysis unit 13, a selection instruction unit 14, a control unit (for example, CPU) 9, a system bus unit 15, and a detection unit 21 are provided.

  The digital broadcast receiving apparatus 1 includes a decoding unit (for example, an MPEG decoder) 5 and a user interface unit (for example, a keyboard or mouse or remote control as an input device, a display device and a speaker device using CRT, liquid crystal, or PDP as an output device) 6 Also equipped.

  The tuner 1 receives a digital broadcast signal from a digital broadcast source from a broadcast station (not shown) via a satellite / terrestrial / cable broadcast transmission network, and a user operation unit such as a remote controller of the user interface unit 6 and a control unit 9. After performing channel selection and detection processing on the frequency of the channel specified via the signal, the data is output to the transmission path decoding unit 3.

  The transmission path decoding unit 3 outputs the MPEG2-TS after digital demodulation and error correction processing to the signal after the channel selection and detection processing from the tuner 1 to the separation unit 4.

  In digital broadcasting, a transport stream standardized by the MPEG system is used for information transmission. The transport stream is composed of transport packets having a fixed length of 188 bytes. In the structure of the transport packet, the first 1 byte is a synchronization byte, and the next 1 bit indicates an error indicator (error indication). This indicates whether there is an error in the packet. If there is an error that cannot be corrected in the error correction process, the error indicator is set to “1” in the transmission path decoding unit 3 (if there is no error) “0”). The error indicator information is information on the error indicator. The MPEG2-TS output from the transmission path decoding unit 3 to the separation unit 4 is an error indicator (in the transport packet) when an uncorrectable error occurs in the transport packet after the error correction processing is performed. Error display) Information must be set to “1”, and “0” if there is no error.

  The separation unit 4 separates a plurality of transport packets of a channel designated via the user operation unit such as a remote controller of the user interface unit 6 and the control unit 9 from the input MPEG2-TS, and separates the plurality of separated transport packets. The transport packet is sent to the writing unit 10, and from a plurality of transport packets of a channel designated via the user operation unit such as a remote controller of the user interface unit 6 and the control unit 9, video and audio PES (Packetized Elementary Stream). ) Or ES (Elementary Stream) is extracted and output to the decoding unit 5. The error indicator (error display) information is set to “1” in the transmission path decoding unit 3 when an error occurs in a plurality of (separated) transport packets of the designated channel output to the writing unit 10. Transport packets are always included.

  The decoding unit 5 decodes the video and / or audio PES or ES from the separation unit 4, and the decoded video and / or audio is output to the user interface unit 6.

  The user interface unit 6 displays and / or reproduces the decoded video and / or audio on a display device and / or speaker device which is an output device.

  The list generation unit 8 creates a position information list based on information from the writing unit 10 described later, and outputs the position information list to the writing unit 10.

  The writing unit 10 performs a process of recording the transport packet separated by the separation unit 4 on the recording medium 11 and outputs information for creating a list in the recording medium 11 to the list generation unit 8. The writing unit 10 records the position information list generated by the list generating unit 8 on the recording medium 11.

  The position information list is information indicating what information is recorded at which position of the recording medium 11. The information for creating the list includes, for example, a sequence header that is a group unit for performing video compression of video data when the writing unit 10 records a transport packet of video data on the recording medium 11 and / or Alternatively, position information indicating the position of a GOP (Group of Picture) or I (Intra) picture by the number of transfer bytes of data from the sequence header located at the beginning of recording, and recording of each GOP and / or I picture It is information such as time information indicating an STC (System Time Clock) count value at the time.

  FIG. 2 shows a specific example of the position information list. Note that the position information may be indicated by the number of transport transport packets instead of the number of transfer bytes in the contents of the position information list. Further, the time information may be indicated by a difference value from the STC count number in the immediately preceding sequence header or GOP and / or I picture. PID (Packet Identifier) information may be added to the position information list. Thereby, for example, even when a transport stream in which a plurality of video data is multiplexed is recorded on the recording medium 11, the position of the respective video data on the recording medium 11 can be managed. Since desired video data can be identified, special reproduction or the like can be efficiently performed.

  The reading unit 12 first reads the position information list from the recording medium 11 and outputs it to the list analysis unit 13.

  The list analysis unit 13 searches for the recording location of the desired transport packet based on the position information list, and causes the reading unit 12 to read the desired transport packet from the recording medium 11 one after another. Control is performed to output the transport packet to the detection unit 21. By performing the reading process using the position information list in this way, it is possible to search for video data in units of moving image compression groups, so that special reproduction can be performed efficiently. In addition, the playback time in the stream and the remaining playback time can be calculated during normal playback and special playback, and the user can be informed of the current playback time and the time until the end of the playback program.

  The detection unit 21 detects the transport packet in which the error indicator (error display) information is set to “1” from the transport packet from the reading unit 12, and outputs the result to the selection instruction unit 14.

  The selection instruction unit 14 controls the separation unit 4 and / or the decoding unit 5 based on the error information from the detection unit 21.

  The control unit 9 controls the overall operation of the digital broadcast receiving apparatus 1 or receives various command signals from the user via the remote controller of the user interface unit 6 and the like via the system bus unit 15 based on the command signals. Various processes are executed by controlling the connected blocks.

  Here, hierarchical transmission will be described with reference to FIG. FIG. 3 shows a transmission spectrum when the number of layers is two layers (hierarchies for fixed reception + layers for portable reception) in the Japanese terrestrial digital broadcasting system ISDB-T as a broadcasting method. Layer B is assigned to 12 segments, and layer A is assigned to one segment. For example, layer B uses a modulation scheme of 64 QAM (64 Quadrature Amplitude Modulation) and a coding rate of 3/4 of the inner code, and the required C Although the / N value is high, the transmission capacity becomes large and reception is possible when reception quality is good. On the other hand, layer A uses a modulation scheme QPSK (Quaternary Phase Shift Keying) and an inner code coding rate of ½. The required C / N value is low, but the transmission capacity is small, and it is natural when reception quality is good. However, reception is possible even when reception quality deteriorates.

  Next, the error indicator information detection process performed by the detection unit 21 will be described with reference to the flowchart of FIG. In this flowchart, for the sake of simplicity, it is assumed that a program that has been hierarchically transmitted with a total number of two layers of strong and weak layers is recorded on the recording medium 11. Then, before this process is started, the list analysis unit 13 acquires the position information list recorded on the recording medium 11 from the reading unit 12, and the reproduction of the program is started based on this list.

  When the reproduction of the program is started, a plurality of transport packets of a desired program recorded on the recording medium 11 are output from the reading unit 12 to the separation unit 4. The separation unit 4 and the control unit 9 analyze PAT (Program Association Table) and / or PMT (Program Map Table) in PSI (Program Specific Information) information, and obtain total layer number information (= 2). Step S28). Thereafter, the detecting unit 21 detects error indicator information of transport packets corresponding to the strong hierarchy, and monitors the number of error packets per unit time to determine whether or not there is an error in the strong hierarchy (step S21). S29). If there is no error in the strong hierarchy, the error indicator information of the transport packet corresponding to the weak hierarchy is detected, and the number of error packets per unit time is monitored (step S31). If it is less than n packets per unit time (n is an integer), it is determined whether or not layer switching is necessary depending on what layer is currently being played back (step S32). Specifically, if the currently reproduced hierarchy is a weak hierarchy, the hierarchy switching is not necessary, and if the currently reproduced hierarchy is a strong hierarchy, the hierarchy switching is necessary. When it is necessary to switch the hierarchy, the selection instruction unit 14 controls the separation unit 4 and / or the decoding unit 5 and / or the interface unit 6 to select / play / display the hierarchy (step S34). On the other hand, if there is no need to switch the hierarchy, step S34 is passed.

  On the other hand, if n packets or more per unit time, it is determined whether or not layer switching is necessary depending on what layer is currently being reproduced (step S33). Specifically, layer switching is not necessary if the currently reproduced layer is a strong layer, and layer switching is necessary if the currently reproduced layer is a weak layer. When it is necessary to switch the hierarchy, the selection instruction unit 14 controls the separation unit 4 and / or the decoding unit 5 and / or the interface unit 6 to select / play / display the hierarchy (step S35). On the other hand, if there is no need to switch the hierarchy, step S35 is passed.

  On the other hand, if there is an error in the strong hierarchy, since reproduction is impossible in all hierarchies, a display for notifying the user that there was a reception failure during recording is performed on the display section of the interface section 6 (step S30). ).

  The above processing is performed until the reproduction of the program is stopped, and when it is stopped, the processing is ended (step S36).

  The display for notifying the user that there was a reception failure during recording on the display unit of the interface unit 6 in step S30 is, for example, a display as shown in FIG. In FIG. 5, the display unit 30 of the interface unit 6 and a message 31 by OSD display are shown. By displaying in this way, it is possible to avoid discomfort for the user.

  In the above description, a plurality of separated transport packets output from the separation unit 4 to the writing unit 10 are all of hierarchical services or when the apparatus receives a digital broadcast that is hierarchically transmitted. Some transport packets.

  The transport packets recorded on the recording medium 11 are not limited to those separated by the tuner 1, the transmission path decoding unit 3, and the separation unit 4, but are connected to external devices via an IEEE 1394 interface, a wireless LAN, the Internet, etc. (not shown). It may be a transport packet input from. In this case as well, the same operation can be performed by setting error indicator information at the time of reception.

  Although the embodiment has been described above, in the description of the flowchart of FIG. 4, it has been described that reproduction is not possible in all layers when there is an error in the strongest layer, but some video / audio disturbance is allowed. If so, there is no problem to play the strongest layer. In this case, it is better to inform the user that there was a reception failure during recording on the display unit of the interface unit 6 and that the reproduced video / audio is disturbed. For example, the display is as shown in FIG. In FIG. 6, the display unit 32 of the interface unit 6 and a message 33 by OSD display. By displaying in this way, it is possible to reduce discomfort to the user even if the video / audio is disturbed during playback.

  Further, an error indicator information detection processing unit is provided between the separation unit 4 and the writing unit 10, and when an error occurs in the strong hierarchy and / or the weak hierarchy when recording on the recording medium 11, the user is notified of the error after recording. It is possible to inform that. In general, a display similar to a recorded program list showing the contents of a program recorded on a recording medium is known. That is, the recorded program list describes the detailed contents of the program recorded on the recording medium, and includes the recording date and time, recording start time, program length, channel, recording mode, and program name. It is. FIG. 7 shows a specific example in which error information of a program recorded in association with such information is displayed. In FIG. 7, the display unit 34 of the interface unit 6 and the recorded program list 35 by OSD display, no error = “”, only the weak layer has an error = “×”, and both the strong and weak layers have an error = “××”. Is displayed in the left column. For example, the program “12/12 (Sunday) PM3: 30 2h30m 011 TS Great Sumo Winter Place” means that an error has occurred in both the strong class and the weak class. In addition, the program “12/10 (Friday) AM6: 30 1h00m 061 TS News” means that an error has occurred in the weak hierarchy. By displaying in this way, the user can be notified of the presence or absence of errors during recording (that is, reception quality) before playing the recorded program, so the video / audio is disturbed during playback. Can also reduce discomfort to the user.

  In the above-described embodiment, the Japanese ISDB-T standard hierarchical transmission system has been described as an example. However, the Japanese ISDB-S, European DVB-H, US, China, and other national hierarchies have been described. The technology of the present invention can be applied to all digital broadcasting standards that can be transmitted.

  As mentioned above, although embodiment and the modification of this invention were demonstrated, these are the illustrations for description of this invention, Comprising: It is not the meaning which limits the scope of the present invention only to this embodiment and modification. The present invention can also be implemented in various other digital broadcast receiving apparatuses.

The block diagram which shows the structure of the digital broadcast receiver with a built-in storage apparatus. The figure which shows the specific example of the content of a positional information list. The figure explaining hierarchical transmission. Explanatory drawing of the flowchart which shows the error indicator information detection process which a detection part performs. The figure which shows the concrete OSD display screen when there exists an error in a strong hierarchy. The figure which shows the concrete OSD display screen when there exists an error in a strong hierarchy. The figure which shows the concrete OSD display screen when error information is added to the recorded program list.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital broadcast receiver 2 Tuner 3 Transmission path decoding part 4 Separation part 5 Decoding part 6 User interface part 8 List generation part 9 Control part 10 Writing part 11 Recording medium 12 Reading part 13 List analysis part 14 Selection instruction | indication part 15 System bus part 21 Detection unit 30, 32, 34 Display unit 31, 33 Message by OSD display 35 Recorded program list by OSD display

Claims (6)

Record all or a part of the data stream of the hierarchical service after receiving and demodulating a digital broadcast having two or more hierarchical services in the same transmission channel, and reproduce the recorded data stream recorded on the recording medium In a digital broadcast receiver capable of
Recording means for adding error information that can determine whether or not there is an error in all or part of the data stream of the hierarchical service after receiving / demodulating digital broadcasting to the data stream, and recording data stream of the recording medium And reproducing means for reproducing a recorded data stream by switching to a more appropriate hierarchical service in response to the number of errors in the added error information being greater than or less than a predetermined number at the time of reproduction. Digital broadcast receiver.   If the playback unit cannot select a more appropriate hierarchical service when switching to a more appropriate hierarchical service based on the management information or the error information during playback of the recording data stream of the recording medium, the playback unit displays a message to that effect. The digital broadcast receiver according to claim 1, which is displayed on the screen. In a digital broadcast receiving apparatus capable of recording a data stream after receiving / demodulating a digital broadcast on a recording medium and reproducing the recorded data stream recorded on the recording medium,
Recording means for adding error information to a data stream to record whether or not there is an error in all or a part of the data stream after receiving / demodulating digital broadcasting, and recording the recording data stream on the recording medium And a reproducing means for reproducing the recording data stream based on whether the number of errors in the added error information is greater than or less than a predetermined number.   The error indicator information detection processing means for detecting that the number of errors in the error information is greater than or less than a predetermined number, and displays the presence or absence of errors in the received / demodulated digital broadcast data stream. The digital broadcast receiving apparatus according to any one of the above. Record all or a part of the data stream of the hierarchical service after receiving and demodulating a digital broadcast having two or more hierarchical services in the same transmission channel, and reproduce the recorded data stream recorded on the recording medium A digital broadcast receiving method,
Adding to the data stream error information that can determine whether or not there is an error in all or part of the data stream of the hierarchical service after receiving / demodulating the digital broadcast, and recording the recording data stream on the recording medium; A digital broadcast reception comprising: a step of switching to a more appropriate hierarchical service and reproducing a recorded data stream in response to the number of errors in the added error information being greater than or less than a predetermined value at the time of reproduction Method. A digital broadcast receiving method for recording a data stream after receiving and demodulating a digital broadcast on a recording medium and reproducing the recorded data stream recorded on the recording medium,
A step of adding to the data stream error information that can determine whether or not there is an error in all or part of the data stream after receiving and demodulating the digital broadcast, and recording the recording data stream on the recording medium, And a step of reproducing a recording data stream based on whether the number of errors in the added error information is greater than or less than a predetermined value.

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