JP2012070344A - Digital broadcast reception device and digital broadcast reception method - Google Patents

Abstract

[PROBLEMS] To shorten an image non-display period at the time of channel selection.
A tuner that receives and demodulates a digital broadcast signal of a selected channel, a demultiplexer that extracts a packet from the demodulated stream, and a video included in a video data packet of the extracted packet. An MPEG video decoder 105 that decodes data, a storage unit 107 that stores management information including, for each channel, program identification information including a packet identifier of a packet that stores program data, and a control unit 110. If the program specifying information of the selected channel is in the management information, the program specifying information of the selected channel is acquired, and the packet corresponding to the packet identifier included in the acquired program specifying information is The multiplexer 102 extracts and updates the packet identifier of the selected channel. If it is, it updates the packet identifier contained in the program specific information of the selected channel.
[Selection] Figure 1

Description

  The present invention relates to a digital broadcast receiving apparatus and a digital broadcast receiving method.

  In digital broadcasting, video data and audio data of one or more programs are multiplexed and broadcast as TS (Transport Stream). Video data and audio data are packetized (one packet is composed of 188 bytes), and each packet is numbered by arbitrary packet identifier information called PID. In the TS, PSI (Program Specific Information) including information necessary for specifying program data such as video data and audio data constituting the program is multiplexed. PSI includes a PAT (Program Association Table) and a PMT (Program Map Table).

  When selecting a digital broadcast, the digital broadcast receiver first acquires a PAT, and acquires the PMT by referring to the PID of the PMT described in the PAT. The PMT describes video data PID, audio data PID, subtitle data PID, PCR (Program Clock Reference) PID, and ECM (Entimental Control Message) PID. A program can be reproduced by acquiring a packet. In other words, it is necessary to acquire PAT and PMT in digital broadcast tuning, but since these packets are periodically multiplexed, it is necessary to wait until the packets are acquired, such as video data and audio data. It takes time to acquire these packets and start storing these data. This time is a video non-display period in which no video is displayed.

  Therefore, the digital broadcast receiver described in Patent Document 1 stores the PID of the program data of the channel when the channel selection process was last performed, and uses the stored PID when the channel is selected next time. This shortens the video non-display period.

JP 2010-016663 A (page 8, FIG. 4)

  In the digital broadcast receiver described in Patent Document 1, when the PID of video data and audio data changes due to, for example, a program change after the last channel selection processing, the stored PID and broadcast There is a difference with the PID of the middle program. Therefore, in such a case, when the digital broadcast receiver described in Patent Document 1 selects a channel by referring to the PID stored at the next channel selection, the PID of the video data and audio data of the program being broadcast is selected. Therefore, the PID of the video data and the audio data has to be taken again during the channel selection process, and the video non-display period becomes long.

  Therefore, an object of the present invention is to shorten the video non-display period at the time of channel selection.

A digital broadcast receiving apparatus according to the present invention,
A tuner that receives and demodulates the digital broadcast signal of the selected channel;
A demultiplexer that extracts packets from the stream demodulated by the tuner;
A video decoder for decoding video data included in a video data packet among the packets extracted by the demultiplexer;
A storage unit for storing management information including program identification information including a packet identifier of a packet storing program data for each channel;
A control unit,
The controller is
When the program identification information of the selected channel is in the management information, the program identification information of the selected channel is acquired, and a packet corresponding to the packet identifier included in the acquired program identification information is acquired. Extraction packet prediction setting means for causing the demultiplexer to extract;
Program identification information processing means for updating a packet identifier included in the program identification information of the selected channel when the packet identifier of the selected channel is updated.

  According to the present invention, the video non-display period at the time of channel selection can be shortened.

1 is a block diagram schematically showing a configuration of a digital broadcast receiving apparatus according to Embodiment 1. FIG. 6 is a schematic diagram showing a program specific information management table which is an example of management information in Embodiment 1. FIG. 3 is a block diagram schematically showing functions of a control unit in Embodiment 1. FIG. 3 is a schematic diagram showing a structure of a TS header in Embodiment 1. FIG. 3 is a flowchart showing a channel selection process of the digital broadcast receiving device according to the first embodiment. 4 is a flowchart showing a program specific information acquisition update process in the first embodiment. 4 is a flowchart showing a program specific information update process in the first embodiment. 6 is a flowchart showing PES packet detection processing in the first embodiment. 4 is a schematic diagram of video data packets stored in a buffer unit in Embodiment 1. FIG. 6 is a block diagram schematically showing functions of a control unit in Embodiment 2. FIG. 10 is a flowchart showing I picture detection processing in the second embodiment. 6 is a schematic diagram illustrating video data packets stored in a buffer unit according to Embodiment 2. FIG.

Embodiment 1 FIG.
FIG. 1 is a block diagram schematically showing the configuration of the digital broadcast receiving apparatus 100 according to the first embodiment. The digital broadcast receiving apparatus 100 includes a tuner 101, a demultiplexer 102, a B-CAS card 103, a descrambler 104, an MPEG video decoder 105, an MPEG audio decoder 106, a storage unit 107, a control unit 110, A key receiving unit 111 and a remote controller 112 are provided. In addition, the code | symbol in the parenthesis of FIG. 1 is a code | symbol which shows the structure in Embodiment 2. FIG.

The tuner 101 demodulates the digital broadcast signal obtained from the antenna 120 that receives the digital broadcast signal.
The demultiplexer 102 separates necessary packets from a transport stream (hereinafter referred to as TS). The demultiplexer 102 includes a buffer unit 102A, and temporarily stores video data packets and audio data packets in the separated packets.

Although not shown, the B-CAS card 103 is connected to the digital broadcast receiving apparatus 100 via, for example, a card slot, and controls a decryption key for descrambling when an ECM is given from the control unit 110. Part 110 is provided.
The descrambler 104 uses the decryption key provided from the B-CAS card 103 to decrypt (descramble) the encrypted data.

The MPEG video decoder 105 performs MPEG decoding (decoding) on the MPEG video data encoded by the MPEG method, and outputs a video signal. The video signal output from the MPEG video decoder 105 is sent to the display unit 121, and a video corresponding to this video signal is displayed on the display unit 121.
The MPEG audio decoder 106 decodes (decodes) MPEG audio data encoded by the MPEG method, and outputs an audio signal. The audio signal output from the MPEG audio decoder 106 is sent to the speaker 122.

The storage unit 107 stores management information for managing program specifying information. The management information includes a packet identifier (PID) of a packet storing program data as program specifying information for each channel. Here, the program data includes video data, audio data, caption data, PCR, and ECM.
For example, the management information can be configured as information in a table format as shown in FIG. FIG. 2 is a schematic diagram showing a program specifying information management table 130 which is an example of management information. The program identification information management table 130 includes a service ID column 130A, a PAT version number column 130B, a PMT version number column 130C, a video data PID column 130D, an audio data PID column 130E, and a subtitle data PID. A column 130F, a PCR PID column 130G, and an ECM PID column 130H are provided.
The service ID column 130A stores a service ID that is identification information for identifying a channel.
The PAT version number field 130B stores the PAT version number in which the PID of the PMT having the version number specified in the PMT version number field 130C is stored.
The PMT version number column 130C stores the version number of the PMT from which the PID such as video data has been acquired.
The video data PID column 130D stores the PID of the video data.
The audio data PID column 130E stores the PID of the audio data.
The PID column 130F of caption data stores the PID of caption data.
The PCR PID column 130G stores the PID of the PCR.
The ECM PID column 130H stores the ECM PID.

The storage unit 107 stores an application program for performing processing in the control unit 110.
For example, the storage unit 107 can be configured by a flash ROM 108 that is a non-volatile memory and a RAM 109 that is a volatile memory, and the flash ROM 108 stores a program specific information management table 130 and an application program. Read out to the RAM 109.

The control unit 110 controls processing in the digital broadcast receiving apparatus 100.
FIG. 3 is a block diagram schematically showing functions of the control unit 110. As shown in the figure, the control unit 110 includes reproduction control means 110A, prefetch channel selection means 110B, PES packet detection means 110G, and PES packet transfer means 110H.

  The reproduction control unit 110 </ b> A controls the entire digital broadcast reproduction process in the digital broadcast receiving apparatus 100. For example, upon receiving a channel selection instruction from the remote controller 112 via the key receiving unit 111, the reproduction control unit 110A controls the tuner 101 so that a digital broadcast signal of a channel corresponding to the channel selection instruction can be received. Further, the reproduction control unit 110A acquires the ECM from the ECM packet, sends this ECM to the B-CAS card 103, and acquires the decryption key from the B-CAS card 103. Then, the reproduction control unit 110 </ b> A sets the acquired decryption key in the descrambler 104.

  The prefetch channel selection unit 110B acquires the program identification information of the channel corresponding to the channel selection instruction, and sets the PID indicated by the program identification information in the demultiplexer 102. Further, the prefetch channel selection means 110B performs a process of acquiring the program specifying information and a process of updating the program specifying information. Here, the prefetch channel selection unit 110B includes an extracted packet prediction setting unit 110C and a program identification information processing unit 110D.

  The extracted packet prediction setting unit 110C extracts the program specifying information of the channel corresponding to the channel selection instruction from the program specifying information management table 130 stored in the storage unit 107, and the video data packet indicated by the extracted program specifying information , The PID of the audio data packet, the PID of the caption data packet, the PID of the PCR packet, and the PID of the ECM packet are set in the demultiplexer 102.

The program specific information processing means 110D acquires the program specific information from the TS, performs processing for storing the program specific information in the program specific information management table 130, and also stores the program specific information stored in the program specific information management table 130. Process to update.
Here, the program specific information processing unit 110D includes a program specific information acquisition / updating unit 110E and a program specific information updating unit 110F.
The program specific information acquisition / updating means 110E stores the program specific information in the program specific information management table 130 and performs a process of updating the program specific information.
The program identification information updating unit 110F stores the program identification information stored in the program identification information management table 130 when the program identification information acquisition / updating unit 110E is not performing any of the process of storing and updating the program identification information. Process to update.

The PES packet detection unit 110G detects a video data packet that includes the head of picture data among the video data packets stored in the buffer unit 102A of the demultiplexer 102. For example, when the payload unit start indicator of the TS header is “1”, the PES packet detection unit 110G determines that the top of the picture data is included in the video data packet having such a TS header. FIG. 4 is a schematic diagram showing the structure of the TS header 131. As shown, the TS header 131 includes a synchronization byte 131A, a transport error indicator 131B, a payload unit start indicator 131C, a transport priority 131D, a PID 131E, a transport scramble control 131F, and an adaptation field control. 131G and a continuity index 131H. If the payroit unit start indicator 131C is “1”, the head of the PES packet is included, and the head of the picture data is always arranged at the head of the PES packet.
Then, the PES packet detection unit 110G generates PES packet head position information indicating the position where the video data packet including the head of the picture data is stored in the buffer unit 102A. Note that the PES packet detection unit 110G stores the specified PES packet head position information in the storage unit 107.

When the decryption key is acquired from the B-CAS card 103, the PES packet transfer unit 110H reads the video data packet from the position specified by the PES packet head position information from the buffer unit 102A, and transfers it to the descrambler 104. The video data packet is decoded. The PES packet transfer unit 110H transfers the decoded video data packet decoded by the descrambler 104 to the MPEG video decoder 105, and performs MPEG decoding on the decoded video data packet.
The PES packet transfer unit 110H also reads out the audio data packet from the buffer unit 102A, transfers it to the descrambler 104, and decodes the audio data packet. The PES packet transfer unit 110H transfers the decoded audio data packet decoded by the descrambler 104 to the MPEG audio decoder 106, and MPEG decoding is performed on the decoded audio data packet. Here, the PES packet transfer unit 110 </ b> H may transfer the audio data packet corresponding to the video data packet transferred to the descrambler 104 to the descrambler 104.

The key receiving unit 111 receives an operation signal corresponding to a key operation accepted by the remote controller 112.
The remote control 112 receives an input of a key operation from the user.

  FIG. 5 is a flowchart showing channel selection processing of digital broadcast receiving apparatus 100 according to Embodiment 1. In the digital broadcast receiving apparatus 100, the application program is read from the flash ROM 108 to the RAM 109, and the application program is activated to function as the control unit 110. Further, when the program specific information management table 130 is stored in the flash ROM 108, the control unit 110 reads the program specific information management table 130 into the RAM 109, and the control unit 110 reads the program specific information management table read into the RAM 109. Processing is performed using the table 130. When the program specific information management table 130 is not stored in the flash ROM 108, the control unit 110 generates the program specific information management table 130 in the RAM 109.

  When the user presses the channel selection key of the remote controller 112 to switch the channel currently being viewed, the key receiving unit 111 receives an operation signal corresponding to the operation of pressing the channel selection key (S10).

  The reproduction control means 110A starts tuner control for the tuner 101 in order to receive and demodulate the digital broadcast signal of the channel selected by the operation signal received in step S10 (S11).

When tuner control is started in step S11, the prefetch channel selection unit 110B starts prefetch channel selection processing. The prefetch channel selection process is a process of steps S12 to S16.
First, the extracted packet prediction setting unit 110C determines whether or not the program specific information of the channel to be selected can be extracted from the program specific information management table 130 (S12). If the extracted packet prediction setting unit 110C cannot extract the program identification information of the channel selection destination channel (No in step S12), the process proceeds to step S13, and the program identification information of the channel selection destination channel is obtained. If it can be extracted (Yes in step S12), the process proceeds to step S14.

  In step S13, the program specific information acquisition update unit 110E performs a program specific information acquisition update process. The program specific information acquisition / update process will be described in detail with reference to FIG.

  In step S14, the extracted packet prediction setting unit 110C extracts the program identification information of the channel to be selected from the program identification information management table 130, and from this program identification information, the PID of the video data packet, the PID of the audio data packet, The PID of the caption data packet, the PID of the PCR packet, and the PID of the ECM packet are extracted and set in the demultiplexer 102. The demultiplexer 102 in which these are set acquires a packet corresponding to the set PID. Further, the demultiplexer 102 stores the acquired video data packet and audio data packet in the buffer unit 102A.

  Here, when the PID is set in the demultiplexer 102 in step S14, the processes in steps S15 and S16 and the processes in steps S17 to S19 are performed in parallel.

  First, the program specific information update unit 110F determines whether or not the program specific information acquisition update process of step S13 has been started (S15). And the program specific information update means 110F progresses to the process of step S16, when the program specific information acquisition update process has not been started (No in step S15).

  In step S16, the program specific information update unit 110F performs program specific information update processing. The program specific information update process will be described in detail with reference to FIG.

  Further, the PES packet detection means starts the PES packet detection process (S17). The PES packet detection process will be described in detail with reference to FIG.

  Next, the PES packet transfer means 110H transfers the video data packet corresponding to the head position of the PES packet to the MPEG video decoder 105, and also transfers the audio data packet to the MPEG audio decoder 106 (S18).

  Then, the MPEG video decoder 105 and the MPEG audio decoder 106 MPEG-decode the input video data packet and audio data packet, respectively (S19). The MPEG-decoded video signal is output to the display unit 121, and the MPEG-decoded audio signal is output to the speaker 122.

FIG. 6 is a flowchart showing the program specific information acquisition update process.
First, the program specific information acquisition / update means 110E of the control unit 110 adds a new record to the program specific information management table 130, and stores the service ID corresponding to the selected channel in the service ID column 130A of the added record. Then, initial values such as a null value are stored in the other columns 130B to 130H (S20).

  Next, the program specific information acquisition / update unit 110E of the control unit 110 starts acquisition of a PAT packet that is a fixed PID from the demultiplexer 102 (S21).

  Next, the program specific information acquisition update unit 110E checks whether or not a PAT packet has been acquired (S22). If the PAT packet is acquired (Yes in step S22), the program specific information acquisition / updating means 110E proceeds to the process of step S23. If the PAT packet is not acquired (No in step S22), the program specific information acquisition / updating means 110E Proceed to the process.

  In step S23, the program specific information acquisition / update unit 110E analyzes the acquired PAT packet and acquires the PAT version number.

  Next, the program identification information acquisition / updating means 110E identifies the record in which the service ID of the selected channel is stored in the service ID column 130A in the program identification information management table 130, and the version of the PAT acquired in step S23. It is determined whether or not the number has been updated from the PAT version number stored in the PAT version number column 130B of the identified record (S24). In addition, the program specific information acquisition update means 110E judges that it is updated when these version numbers are different. Then, the program specific information acquisition / updating means 110E proceeds to the process of step S25 if updated (Yes in step S24), and proceeds to the process of step S22 if not updated (No in step S24). Return to.

  In step S25, the program specific information acquisition / update unit 110E holds the version number of the PAT acquired in step S23 in the program specific information management table 130. For example, the program specific information acquisition / updating means 110E deletes the PAT version number already stored in the program specific information management table 130 in correspondence with the service ID of the selected channel, and acquires the PAT of the PAT acquired in step S23. Stores a new version number.

  Next, the program specifying information acquisition / updating unit 110E analyzes the acquired PAT packet, specifies the PID of the PMT packet, and starts acquiring the PMT packet (S26).

  Then, the program specific information acquisition / update means 110E confirms whether or not the PMT packet has been acquired (S27). When the PMT packet is acquired (Yes in step S27), the program specific information acquisition / updating means 110E proceeds to the process of step S28, and when the PMT packet is not acquired (No in step S27), the program specifying information acquisition / updating means 110E Proceed to the process.

  In step S28, the program specific information acquisition update unit 110E analyzes the acquired PMT packet and acquires the version number of the PMT.

  Next, the program identification information acquisition / updating means 110E identifies the record in which the service ID of the selected channel is stored in the service ID column 130A in the program identification information management table 130, and the version of the PMT acquired in step S28. It is determined whether or not the number has been updated from the version number of the PMT stored in the PMT version number column 130C of the identified record (S29). In addition, the program specific information acquisition update means 110E judges that it is updated when these version numbers are different. Then, the program specific information acquisition / updating means 110E proceeds to the process of step S30 when updated (Yes in step S29), and proceeds to the process of step S27 when not updated (No in step S29). Return to.

  In step S30, the program specific information acquisition / updating means 110E holds the PMT version number acquired in step S28 in the program specific information management table 130, analyzes the PMT packet, and analyzes the PID and audio data packet of the video data packet. The PID of the subtitle data packet, the PID of the PCR packet, and the PID of the ECM packet are acquired, and whether or not there is a change in the content stored in the program specific information management table 130 corresponding to the selected channel If there is a change, the changed content is stored in the program specifying information management table 130.

  On the other hand, if the PAT packet has not been acquired in step S22 (No in step S22), the program specific information acquisition / update means 110E proceeds to the process of step S31. In step S31, the program specific information acquisition update unit 110E confirms whether or not a PMT packet has been acquired. When the PMT packet is acquired (Yes in Step S31), the program specific information acquisition / updating unit 110E proceeds to the process of Step S28, and when the PMT packet is not acquired (No in Step S31), The process returns to step S22.

  If the PMT packet has not been acquired in step S27 (No in step S27), the program specific information acquisition / updating means 110E proceeds to the process of step S32. In step S32, the program specific information acquisition update unit 110E confirms whether or not a PAT packet has been acquired. If the PAT packet is acquired (Yes in step S32), the program specific information acquisition / updating means 110E returns to the process of step S23, and if the PAT packet is not acquired (No in step S32), The process returns to step S27.

FIG. 7 is a flowchart showing the program identification information update process.
First, the program identification information updating unit 110F identifies the record in which the service ID of the channel to be selected is stored in the service ID column 130A in the program identification information management table 130, and the PAT version number column 130B of the identified record. The value stored in is initialized (S40). For example, the program specifying information updating unit 110F deletes the value in the PAT version number column 130B of the specified record and stores an initial value such as a null value.

  And the program specific information update means 110F performs the process from step S41 to S52. Here, these processes are the same as the processes from steps S21 to S32 in FIG. 6, but are performed by the program specific information update unit 110F instead of the program specific information acquisition update unit 110E.

  Although not shown in FIGS. 6 and 7, when the program specific information management table 130 is stored in the flash ROM 108 and read out to the RAM 109 and processed, the program specific information management table 130 is stored. It is desirable to store the updated program specific information management table 130 in the flash ROM 131 each time the information stored in the is updated.

  FIG. 8 is a flowchart showing the PES packet detection process.

  First, the PES packet detection unit 110G acquires video data packets from the buffer unit 102A of the demultiplexer 102 according to the buffered order (S60).

  Next, the PES packet detection unit 110G starts analysis of the TS header 131 (see FIG. 4) arranged at the head of the acquired video data packet (S61).

  The PES packet detection unit 110G analyzes the TS header 131 and determines whether or not the payload unit start indicator 130C is “1” (S62). When the payload unit start indicator is “1” (Yes in Step S62), the PES packet detection unit 110G proceeds to the process of Step S63, and when the payload unit start indicator is not “1” (No in Step S62). ), The process returns to step S60 to obtain the next video data packet.

  In step S63, the PES packet detection unit 110G acquires the position where the video data packet acquired in step S60 is stored in the buffer unit 102A as PES packet head position information. The PES packet detection unit 110G stores the PES packet head position information thus acquired in the storage unit 107.

  Next, when the PES packet head position information is acquired, the PES packet transfer unit 110H confirms whether or not the reproduction control unit 110A has acquired the decryption key from the B-CAS card 103 (S64). When the decryption key is acquired (Yes in step S64), the PES packet transfer unit 110H proceeds to the process of step S65. When the decryption key is not acquired (No in step S64), the PES packet transfer unit 110H acquires the decryption key. Wait until it is obtained.

  In step S65, the PES packet transfer unit 110H reads the video data packet from the position indicated by the PES packet head position information acquired in step S63 from the buffer unit 102A, transfers it to the descrambler 104, and starts decoding. Let Here, the PES packet transfer unit 110H also reads out the corresponding audio data packet from the buffer unit 102A, transfers it to the descrambler 104, and starts decoding.

FIG. 9 is a schematic diagram of video data packets stored in the buffer unit 102A. For example, packets (1) to (9) are stored in the buffer unit 102A as video data packets. The numbers in parentheses indicate the order in which packets are accumulated in the buffer unit 102A. PUSI is a payload unit start indicator, and “0” or “1” is a value of the payload unit start indicator.
Here, the video data packets of packets (1) to (6) are data from the middle of the PES packet because the value of the payload unit start indicator is “0”, and include the head of the picture data. Absent. Therefore, even if the packets (1) to (6) are decoded and transferred to the MPEG video decoder 105, MPEG decoding cannot be performed and no video signal is output. For this reason, even if the packets (1) to (6) are processed by the descrambler 104 and the MPEG video decoder 105, the time for decoding the video data packet and transferring it to the MPEG video decoder is wasted.
Therefore, the PES packet detection unit 110G detects the packet (7) including the head of the PES packet, and the PES packet transfer unit 110H transfers the packet (7) to the descrambler 104 and the MPEG video decoder 105. Save time.

  As described above, according to digital broadcast receiving apparatus 100 according to the present embodiment, when a channel selection process is performed, a PID stored in program specific information management table 130 is used. There is no time to acquire the PID corresponding to the packet of the program data of the previous channel, and acquisition of the program data is started quickly. Further, when the PID corresponding to the program data is updated while the program is being viewed, the updated PID is held in the program identification information management table 130, so that the program can be quickly retrieved without re-acquiring the PID at the next channel selection. Data acquisition starts. Therefore, according to digital broadcast receiving apparatus 100 according to the present embodiment, the video non-display period can be shortened.

  Moreover, according to the digital broadcast receiving apparatus 100 according to the present embodiment, the video data packet including the head of the PES packet is detected from the video data packets acquired until the decryption key is acquired, and the decryption key is set. After the acquisition, the decoding is started from the video data packet and transferred to the MPEG video decoder 105, thereby shortening the time until the MPEG decoding is started. Therefore, according to digital broadcast receiving apparatus 100 according to the present embodiment, the video non-display period can be shortened.

  Furthermore, according to digital broadcast receiving apparatus 100 according to the present embodiment, since the PMT version number is held in program specifying information management table 130, only when the PMT version number is updated, the program data PID update processing is performed. Therefore, according to digital broadcast receiving apparatus 100 according to the present embodiment, it is not necessary to perform update processing of program specifying information every time a PMT packet is acquired, and the processing load on control unit 110 is reduced.

  Then, according to digital broadcast receiving apparatus 100 according to the present embodiment, by storing program specific information management table 130 in flash ROM 108, program specific information management table 130 is erased even when the power is turned off. Therefore, PID accumulation can be started immediately after the power is turned on, and the video non-display period can be shortened by using the PID stored in the program specific information management table 130. .

Embodiment 2. FIG.
In digital broadcasting, an MPEG (Moving Picture Experts Group) 2 system is adopted as a video data encoding system. In the MPEG2 system, video data is divided into three types of data of I picture, P picture, and B picture, and these data are grouped in units of GOP (Group Of Picture). In this MPEG2 system, an I picture contains all information by itself and can be decoded alone. However, since a P picture and a B picture are only difference information, they cannot be decoded without a predicted image. In other words, when digital broadcasting is selected, decoding of video data starts after the appearance of an I picture included in the video data of the channel after channel selection. Since the I picture is arranged at the head of the GOP and the GOP is composed of 15 frames, the I picture appearance waiting period occurs for about 0.5 seconds at the maximum. Therefore, this period is a video non-display period.

In this regard, the digital broadcast receiver described in Patent Document 1 uses the stored PID to start the acquisition of video data earlier, but when the video data was MPEG-decoded, the acquisition was performed. Since the I picture is detected from the head of the video data, if the I picture exists at a position away from the head of the video data, it takes time to start MPEG decoding, and the video non-display period is long. turn into.
Therefore, Embodiment 2 provides a digital broadcast receiving apparatus that solves such problems.

  As shown in FIG. 1, a digital broadcast receiving apparatus 200 according to Embodiment 2 includes a tuner 101, a demultiplexer 102, a B-CAS card 103, a descrambler 104, an MPEG video decoder 105, and an MPEG audio decoder. 106, a control unit 210, a storage unit 107, a key reception unit 111, and a remote control 112. The digital broadcast receiving apparatus 200 according to Embodiment 2 is different from the digital broadcast receiving apparatus 100 according to Embodiment 1 in the configuration and processing of the control unit 210.

  FIG. 10 is a block diagram schematically showing functions of the control unit 210 in the second embodiment. As shown in the figure, the control unit 210 includes a reproduction control unit 110A, a prefetch channel selection unit 110B, a PES packet detection unit 210G, a PES packet transfer unit 210H, a specific packet decoding control unit 210I, and an I picture detection unit 210J. With. The control unit 210 according to the second embodiment is implemented in terms of processing in the PES packet detection unit 210G and the PES packet transfer unit 210H, and in that a specific packet decoding control unit 210I and an I picture detection unit 210J are provided. This is different from the control unit 110 in the first embodiment.

  The PES packet detection means 210G is the head of the picture data among the video data packets stored in the buffer unit 102A of the demultiplexer 102 until the reproduction control means 110A acquires the decryption key from the B-CAS card 103. Is detected. Then, the PES packet detection unit 210G acquires one or more PES packet head position information indicating the position where the video data packet including the head of the picture data is stored in the buffer unit 102A, and acquires the acquired PES packet. PES packet position management information including head position information is generated. Then, the PES packet detection unit 210G causes the storage unit 107 to store the generated PES packet position management information. In the present embodiment, the PES packet detection unit 210G uses PES packet head position information as PES packet position management information, for example, a PES packet stored in a data structure in a table format so that the acquired order can be known. A location management table is generated.

The specific packet decoding control unit 210I extracts the PES packet head position information from the PES packet position management table according to the acquisition order, and acquires the video data packet indicated by the extracted PES packet head position information from the buffer unit 102A.
Then, the specific packet decoding control unit 210I sends the acquired video data packet to the descrambler 104, decodes it, and gives the decoded video data packet to the I picture detection unit 210J.

  The I picture detection unit 210J analyzes the decoded video data packet obtained from the specific packet decoding control unit 210I, and determines whether or not the I picture is included in the packet.

The PES packet transfer unit 210H obtains the PES packet head position information of the video data packet determined to contain the I picture by the I picture detection unit 210J from the PES packet position management table. Then, the PES packet transfer unit 210H reads the video data packet from the position specified by the acquired PES packet head position information from the buffer unit 102A, transfers it to the descrambler 104, and decodes it. Further, the PES packet transfer means 210H transfers the decoded video data packet decoded by the descrambler 104 to the MPEG video decoder 105 to perform MPEG decoding.
The PES packet transfer unit 210H also reads out the audio data packet from the buffer unit 102A, transfers it to the descrambler 104, and decodes the audio data packet. Further, the PES packet transfer means 210H transfers the decoded audio data packet decoded by the descrambler 104 to the MPEG audio decoder 106, and MPEG decoding is performed on the decoded audio data packet. Here, the PES packet transfer unit 210 </ b> H may transfer the audio data packet corresponding to the video data packet transferred to the descrambler 104 to the descrambler 104.

  The channel selection process of digital broadcast receiving apparatus 200 according to Embodiment 2 is substantially the same as the channel selection process of digital broadcast receiving apparatus 100 according to Embodiment 1 shown in FIG. 5, but the PES packet detection process of step S17. Is different from the I picture detection processing. Hereinafter, I picture detection processing will be described.

FIG. 11 is a flowchart showing the I picture detection process.
First, the PES packet detection unit 210G acquires video data packets from the buffer unit 102A of the demultiplexer 102 in the buffered order (S70).

  Next, the PES packet detection unit 210G starts analysis of the TS header 131 (see FIG. 4) arranged at the head of the acquired video data packet (S71).

  The PES packet detection unit 210G analyzes the TS header 131 and determines whether or not the payload unit start indicator 130C is “1” (S72). When the payload unit start indicator is “1” (Yes in Step S72), the PES packet detection unit 210G proceeds to the process of Step S73, and when the payload unit start indicator is not “1” (No in Step S72). ), The process returns to step S70 to obtain the next video data packet.

  In step S73, the PES packet detection unit 210G acquires the position where the video data packet is acquired from the buffer unit 102A in step S70 as PES packet head position information.

  Next, the PES packet detection unit 210G stores the PES packet head position information acquired in step S73 in the PES packet position management table according to the acquisition order (S74).

  Next, the PES packet detection unit 210G confirms whether or not the reproduction control unit 110A has acquired the decryption key from the B-CAS card 103 (S75). When the decryption key is acquired (Yes in step S75), the PES packet detection unit 210G proceeds to the process of step S76, and when the decryption key is not acquired (No in step S75), the process proceeds to step S70. Return and obtain the next video data packet.

  In step S76, the specific packet decoding control unit 210I extracts the PES packet head position information according to the order stored in the PES packet position management table, and extracts the video data packet from the position indicated by the extracted PES packet head position information. The data is read out and transferred to the descrambler 104 to start decoding. Then, the specific packet decoding control unit 210I gives the decoded video data packet to the I picture detection unit 210J.

  Next, the I picture detection unit 210J analyzes the decoded video data packet obtained from the specific packet decoding control unit 210I and determines whether a start code indicating a picture header is included (S77). The start code is a 32-bit value (0x00000100). If the start code indicating the picture header is included (Yes in step S77), the I picture detection unit 210J proceeds to the process of step S78, and if the start code indicating the picture header is not included ( In step S77, the process returns to step S76, and the video data packet including the head of the next PES packet is decoded.

  In step S78, the I picture detection means 210J obtains the picture type included in the picture header of the video data packet.

  Then, the I picture detection unit 210J determines whether or not the acquired picture type is an I picture (S79). If the picture type is an I picture (Yes in step S79), the I picture detection unit 210J proceeds to the process of step S80. If the picture type is not an I picture (No in step S79), the I picture detection unit 210J proceeds to step S76. Returning to the process, the video data packet including the head of the next PES packet is decoded.

In step S80, since the video data packet determined to contain the I picture has been decoded in step S76, the PES packet transfer unit 210H receives the I picture from the buffer unit 102A by the I picture detection unit 210J. The video data packet next to the video data packet determined to be included is read from the buffer unit 102A, transferred to the descrambler 104, and decoding is started.
Then, the PES packet transfer means 210H transfers the video data packet determined to contain the I picture to the MPEG video decoder 105.

FIG. 12 is a schematic diagram showing video data packets stored in the buffer unit 102A. For example, packets (1) to (22) are stored in the buffer unit 102A as video data packets. The numbers in parentheses indicate the order in which packets are accumulated in the buffer unit 102A. PUSI is a payload unit start indicator, and “0” or “1” is a value of the payload unit start indicator. Furthermore, PT is a picture type, “B” indicates that the picture type is a B picture, “P” indicates that the picture type is a P picture, and “I” indicates that the picture type is an I picture. Indicates that there is.
Here, since the video data packets of packets (1) to (19) do not include an I picture, even if packets (1) to (19) are decoded and transferred to MPEG video decoder 105, MPEG decoding cannot be performed, and no video signal is output. For this reason, even if the packets (1) to (19) are processed by the descrambler 104 and the MPEG video decoder 105, the time for decoding the video data packet and transferring it to the MPEG video decoder is wasted time.
Therefore, when the PES packet detection unit 110G detects the packet (1), the packet (10), and the packet (20) including the head of the PES packet in advance and the decryption key is obtained, the packet (1) and the packet (10) Decode in the order of packet (20) to detect I picture. When packet (20) including the head of I picture is detected, decoding starts from packet (21) and MPEG from packet (20) By transferring to the video decoder, wasted time can be saved.

  As described above, according to digital broadcast receiving apparatus 200 according to the present embodiment, the head of the PES packet among the video data packets acquired until the decryption key is acquired when performing the channel selection process. After detecting the included video data packet and obtaining the decryption key, the video data packet including the head of the PES packet is decoded to detect the I picture, and decoding is started from the video data packet including the head of the I picture. Since the data is transferred to the MPEG video decoder, the time until the MPEG decoding starts is shortened, and the video non-display period can be shortened.

  In the second embodiment described above, the processing of steps S70 to S74 is performed until the decryption key is acquired, the PES packet head position information is acquired, and sequentially stored in the PES packet position management table. However, the processing in steps S70 to S74 may be continued until a video data packet including an I picture is found in the processing in steps S76 to S79. By doing so, a video data packet including an I picture can be surely found.

  In the first and second embodiments described above, the video data packet and the audio data packet are stored in the buffer unit 102A of the demultiplexer 102. For example, the video is stored in a portion other than the demultiplexer 102 such as the RAM 109. It can also be configured to buffer data packets and voice data packets.

  If the video data and audio data are not scrambled, the decryption key is obtained from the B-CAS card 103 without providing the B-CAS card 103 and the descrambler 104 shown in FIG. Thus, it is possible to omit the processing of setting the descrambler 104 and decoding the video data packet and the audio data packet by the descrambler. In such a case, it is not necessary to perform step S64 in FIG. 8, and in step S75 in FIG. 11, the acquisition number of the PES packet head position information or the acquisition of the video data packet is started. If a threshold value is provided for the time after that and the threshold value is satisfied, the process may proceed to step S76.

  In the first and second embodiments described above, the digital broadcast receiving devices 100 and 200 output video signals and audio signals to the display unit 121 and the speaker 122. A speaker may be provided to output video or audio.

  DESCRIPTION OF SYMBOLS 100: Digital broadcast receiver 101: Tuner 102: Demultiplexer 102A: Buffer part 103: B-CAS card 104: Descrambler 105: MPEG video decoder 106: MPEG audio decoder 107: Storage part 110, 210: control unit, 110A: reproduction control means, 110B: prefetch channel selection means, 110C: extracted packet prediction setting means, 110D: program specific information processing means, 110E: program specific information acquisition / update means, 110F: program specific information Updating means, 110G, 210G: PES packet detection means, 110H, 210H: PES packet transfer means, 210I: specific packet decoding control means, 210J: I picture detection means, 111: key receiving section, 112: remote control.

Claims (13)

A tuner that receives and demodulates the digital broadcast signal of the selected channel;
A demultiplexer that extracts packets from the stream demodulated by the tuner;
A video decoder for decoding video data included in a video data packet among the packets extracted by the demultiplexer;
A storage unit for storing management information including program identification information including a packet identifier of a packet storing program data for each channel;
A control unit,
The controller is
When the program identification information of the selected channel is in the management information, the program identification information of the selected channel is acquired, and a packet corresponding to the packet identifier included in the acquired program identification information is acquired. Extraction packet prediction setting means for causing the demultiplexer to extract;
And a program specific information processing means for updating the packet identifier included in the program specific information of the selected channel when the packet identifier of the selected channel is updated. Receiver device. The program specifying information processing means, when the program specifying information of the selected channel is not in the management information, a packet packet storing program data in the packet extracted by the demultiplexer The digital broadcast receiving apparatus according to claim 1, wherein an extraction process for extracting an identifier is performed, program specifying information including a packet identifier extracted by the extraction process is generated, and stored in the management information. . The controller is
PES packet detecting means for detecting a head position of a PES packet from among video data packets extracted from the packet by the demultiplexer;
3. The digital broadcast reception according to claim 1, further comprising: a PES packet transfer unit configured to transfer a video data packet after the video data packet in which a head position of the PES packet is detected to the video decoder. apparatus. A descrambler for decoding the packet extracted by the demultiplexer;
The controller is
PES packet detecting means for detecting a head position of a PES packet from among video data packets extracted from the packet by the demultiplexer;
PES packet transfer means for decoding a video data packet after the video data packet in which the head position of the PES packet is detected by the descrambler and transferring the decoded video data packet to the video decoder. The digital broadcast receiving apparatus according to claim 1 or 2, characterized in that: The program specifying information further includes a version number of the PMT that acquired the packet identifier included in the program specifying information,
The program specific information processing means is selected when the PMT version number of the PMT packet acquired from the stream is different from the PMT version number included in the program specific information of the selected channel. The digital broadcast receiving apparatus according to any one of claims 1 to 4, wherein the packet identifier included in the program specifying information of the channel is updated. The storage unit includes a nonvolatile memory,
The digital broadcast receiver according to claim 1, wherein the management information is stored in the nonvolatile memory. The controller is
PES packet detecting means for detecting a head position of a PES packet from among video data packets extracted from the packet by the demultiplexer;
I picture detection means for detecting an I picture from the video data packet in which the head position of the PES packet is detected;
7. The digital broadcast according to claim 1, further comprising: a PES packet transfer means for transferring a video data packet after the video data packet in which the I picture is detected to the video decoder. Receiver device. A descrambler for decoding the packet extracted by the demultiplexer;
The controller is
PES packet detecting means for detecting a head position of a PES packet from among video data packets extracted from the packet by the demultiplexer;
Specific packet decoding control means for causing the descrambler to decode the video data packet in which the head position of the PES packet is detected;
I picture detection means for detecting an I picture from decoded video data packets decoded by the descrambler;
The video data packet after the video data packet next to the video data packet in which the I picture is detected is decoded by the descrambler, and the decoded video data packet after the video data packet in which the I picture is detected is the video. The digital broadcast receiving apparatus according to claim 1, 2, 5 or 6, further comprising PES packet transfer means for transferring to a decoder. A tuner that receives and demodulates the digital broadcast signal of the selected channel;
A demultiplexer that extracts packets from the stream demodulated by the tuner;
A video decoder for decoding video data included in a video data packet among the packets extracted by the demultiplexer;
A storage unit for storing management information including program identification information including a packet identifier of a packet storing program data for each channel;
A digital broadcast receiving method performed by a digital broadcast receiving device comprising a control unit,
When the program specifying information of the selected channel is included in the management information, the control unit acquires the program specifying information of the selected channel and includes a packet identifier included in the acquired program specifying information. An extraction packet prediction setting process for causing the demultiplexer to extract packets corresponding to
A program specifying information processing step of updating the packet identifier included in the program specifying information of the selected channel when the packet identifier of the selected channel is updated; A digital broadcast receiving method as a feature. A PES packet detection process in which the control unit detects a head position of a PES packet from the video data packets in the packets extracted by the demultiplexer;
The PES packet transfer process in which the control unit further includes a PES packet transfer process of transferring a video data packet subsequent to a video data packet in which a head position of the PES packet is detected to the video decoder. Digital broadcast receiving method. The digital broadcast receiver further comprises a descrambler that decodes the packet extracted by the demultiplexer,
A PES packet detection process in which the control unit detects a head position of a PES packet from the video data packets in the packets extracted by the demultiplexer;
A PES packet transfer step of decoding a video data packet after the video data packet in which the head position of the PES packet is detected by the descrambler and transferring the decoded video data packet to the video decoder. The digital broadcast receiving method according to claim 9, wherein: A PES packet detection process in which the control unit detects a head position of a PES packet from the video data packets in the packets extracted by the demultiplexer;
An I picture detection process in which the control unit detects an I picture from a video data packet in which a head position of the PES packet is detected;
The digital broadcast reception according to claim 9, further comprising: a PES packet transfer process in which the control unit transfers a video data packet after the video data packet in which the I picture is detected to the video decoder. Method. The digital broadcast receiver further includes a descrambler that decodes the packet extracted by a demultiplexer,
A PES packet detection process in which the control unit detects a head position of a PES packet from the video data packets in the packets extracted by the demultiplexer;
A specific packet decoding control process in which the control unit causes the descrambler to decode a video data packet in which a head position of the PES packet is detected;
The controller detects an I picture from the decoded video data packet decoded by the descrambler; and
The control unit causes the descrambler to decode video data packets after the video data packet next to the video data packet in which the I picture is detected, and has decoded video after the video data packet in which the I picture is detected. The digital broadcast receiving method according to claim 9, further comprising: a PES packet transfer process of transferring a data packet to the video decoder.

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