JP5045715B2 - Broadcast receiver - Google Patents

Description

The present invention relates to a broadcast receiving apparatus, in particular, advanced ISDB-S (Integrated Services Digital Broadcasting -Satellite), that is, it has been considered to be operated by the advanced satellite broadcasting standards, capable of receiving a broadcast-based download broadcasting about the Do not broadcast receiver.

  For digital broadcasting, real-time broadcasting aimed at viewing programs in real time like conventional television broadcasting, and programs are stored on recording media of broadcast receiving devices such as HDDs and flash memories, etc., as desired by the user There is a download broadcast aimed at playing back and watching on time. Although download broadcasts have the disadvantage that they cannot be viewed in real time, super high-definition broadcasts, 4K2K broadcasts, and other high-bit-rate video distributions that are too difficult to broadcast in real time because they require too much transfer bandwidth. It is also possible to provide a service such as delivering a plurality of programs in a time shorter than real time with a low bit rate video with reduced image quality. As for the mechanism of download broadcasting, as represented by the Japanese Act Villa Service, Internet-type download broadcasting using an IP network as a transmission path, and advanced ISDB-S (Integrated Services Digital Broadcasting-Satelite), that is, advanced satellite broadcasting standards. There is a broadcast type download broadcast that uses a satellite broadcast wave as a transmission path, which is being studied for operation.

  The downloaded program is a media file corresponding to the main body of the video content, a playback control information file in which information necessary for playback control of the downloaded program is described, content title and series information, ECG (Electric Content) in which license information and the like are described. Guide) Each file includes data files (which will be described in detail later with reference to the drawings). In general, the media file is an Mpeg-TS stream, and Mpeg2 and H.264 are included in the Mpeg-TS stream. H.264 format video data, AAC or AC3 format music data, subtitle data, and the like are stored. The Mpeg-TS stream is composed of 192 (or 188) byte fixed-length packets, and video data, music data, and the like are divided and stored in units of packets.

  Here, a configuration and processing contents of a conventional broadcast receiving system will be described with reference to FIGS. FIG. 4 is a diagram showing a configuration of a broadcast transmission / reception system that supports reception of both real-time broadcasts and broadcast-type download broadcasts. FIG. 5 is a diagram showing the structure of a reproduction control information file in which information for reproducing a download program is described. FIG. 6 is a diagram showing the configuration of an ECG data file. FIG. 7 is a flowchart showing download broadcast reservation execution processing in the broadcast receiving apparatus.

  Before describing the configuration of the broadcast transmission / reception system 400, the configuration of the reproduction control information file 500 and the ECG data file 600 will be described with reference to FIGS.

  First, the reproduction control information file 500 will be described. The reproduction control information file 500 includes content attribute information 501 (ERI: Entry Resource Information) in which content information, chapter information, and the like are described, and stream reproduction control information 502 (in which information necessary for reproducing the media file is described). It consists of SCI (Streaming Control Information) and license-related information 503 (LLI: License Link Information) necessary for reproducing a copyright-protected media file.

  In the net-type download broadcasting, each file constituting the above download program is published on a Web server, and each file constituting the above download program is acquired and stored in units of files at a timing desired by the broadcast receiving apparatus. . On the other hand, in broadcast-type download broadcasting, all files constituting a download program are multiplexed by a download broadcast signal multiplexing method, and broadcast on a broadcast wave at a predetermined download broadcast time. The broadcast receiving apparatus receives the multiplexed data from the broadcast wave at the download broadcast time, demultiplexes it, and stores it. The download broadcast signal multiplexing method uses a variable length packet multiplexing method in consideration of transmission efficiency. For example, in Japan's advanced BS digital broadcasting, a TLV (Type Length Value) multiplexing method is used as a download broadcast signal multiplexing method, and the download broadcast signal is called a TLV stream (see, for example, Non-Patent Document 1).

  Next, the ECG data file 600 will be described. In real-time broadcasting, information on a program to be broadcast is described as EPG (Electric Program Guide) information as SI information in a PMT packet in the Mpeg-TS stream. The broadcast receiving apparatus provides an electronic program guide based on this EPG information. On the other hand, in download broadcasting, there exists an ECG (Electric Content Guide) data file 600 in which detailed information of a download program is described as equivalent to EPG information in real-time broadcasting. A program ID (CRID) that is a unique ID is assigned to each downloaded program, and the ECG data file 600 includes group information 601 (GI: Group Information) that describes the group to which the downloaded program belongs based on the program ID. ), Program information 602 (PI: Program Information) describing details of the contents of the downloaded program, license reference information 603 (LI: License Information) describing the usage conditions of the downloaded program, downloadable program purchase period, Purchase information 604 (PuI: Purchase Information) in which prices are described, and download control information 605 (DCI: Download) in which information necessary for downloading is described (Control Information).

  A conventional broadcast transmission / reception system 400 shown in FIG. 4 is a broadcast transmission / reception system capable of receiving a real-time broadcast and receiving a broadcast-type download broadcast using the reproduction control information file 500 and the ECG data file 600 described above. The broadcast transmission / reception system 400 includes a broadcast transmission device 4100 and a broadcast reception device 4200.

  The broadcast transmission device 4100 is equipment on the broadcast station side, and broadcasts real-time broadcasts and broadcast-type download broadcasts on broadcast waves via the transmission unit 4101 according to the broadcast schedule. For example, in the case of real-time broadcasting, the program video to be broadcast is encoded into Mpeg2 or the like by the video / audio encoding unit 4102, and information on the program to be broadcast and information on the broadcast schedule are simultaneously converted into EPG data by the EPG data generation unit 4103. An Mpeg-TS stream to be broadcast is generated by being input to the MPEGTS multiplexing unit 4106.

  On the other hand, in the case of broadcast-type download broadcasting, a program video to be broadcast in advance is authored and recorded in the content storage unit 4104, and ECG data of the program to be broadcast at the same time is generated by the ECG data generation unit 4105, and each TLV multiplexing unit A TLV stream to be broadcast is generated by inputting to 4107.

  The Mpeg-TS stream for real-time broadcasting and the TLV stream for broadcast-type download broadcasting generated in this way are switched by the switching unit 4108 according to the broadcasting schedule and input to the transmission unit 4101. The transmission unit 4101 broadcasts the input stream on the broadcast wave as described above.

  The broadcast receiving device 4200 is a broadcast receiving device that supports both real-time broadcasting and broadcast-type download broadcasting. The receiving unit 4201 receives the broadcast wave transmitted from the broadcast transmitting device 4100. The receiving unit 4201 extracts a stream from the received broadcast wave. If the extracted stream is an Mpeg-TS stream for real-time broadcasting, the stream is input to the MpegTS demultiplexing unit 4202. If the extracted stream is a TLV stream for broadcast download broadcasting, TLV demultiplexing is performed. Input to the unit 4203. The MpegTS demultiplexing unit 4202 separates the input Mpeg-TS stream into an AV stream and EPG data, and the EPG data is stored in the EPG accumulation unit 4204.

  On the other hand, the TLV demultiplexing unit 4203 separates the input TLV stream into an AV stream and ECG data, stores the AV stream in the content storage unit 4206, and stores the ECG data in the ECG storage unit 4205. Although not shown, it is considered that ECG data can be acquired not only via broadcast waves but also from a server on the Internet via a network. In this case as well, ECG data acquired via the network is ECG data. It is stored in the storage unit 4205.

  Broadcast receiving apparatus 4200 uses video / audio switching section 4207 to switch between displaying a real-time broadcast program and displaying a download program in accordance with a user operation. When the user selects a download program, the AV stream of the program stored in the content storage unit 4206 is input to the video / audio processing unit 4208, and the decoded video / audio is provided to the user through the video / audio output unit 4209.

  The broadcast receiving apparatus 4200 can also provide the user with program information obtained from the EPG storage unit 4204 and the ECG storage unit 4205 in the form of, for example, an electronic program guide, and allow viewing and reservation. For example, the broadcast receiving apparatus 4200 generates an electronic program guide for download broadcasting based on group information, program information, and the like of ECG data stored in the ECG storage unit 4205 and presents it to the user. Here, the flow of processing from when the user reserves a download broadcast from the electronic program guide to when the reservation is completed will be described with reference to FIG. Here, the download program reserved for download by the user is stored in a reservation information storage unit (not shown).

  The user selects a download program from the electronic program guide presented by the ECG storage unit 4205 and inputs a reservation (step S0001). When the reservation is entered, the ECG accumulation unit 4205 extracts the corresponding ECG data 600 from the program ID of the reserved download program, and refers to the schedule 606 of the download control information 605 in the ECG data 600 (step S0002). In this schedule 606, information for selecting a channel on which a download program is broadcast is stored as a serviceref value, and the start date and time of download broadcasting is stored as a start value. The download broadcast end date and time are stored.

  The ECG storage unit 4205 causes the broadcast receiving device 4200 to stand by until the download broadcast start date and time obtained from the schedule 606 (step S0003). The receiving unit 4201 is instructed to select a channel on which the reserved download program is broadcast (step S0004). When the broadcast wave received each time is a TLV stream, the receiving unit 4201 inputs the received TLV stream to the TLV demultiplexing unit 4203. The TLV demultiplexing unit 4203 extracts the AV stream from the input TLV stream and records it in the content storage unit 4206 (step S0005). The broadcast receiving apparatus 4200 executes the above-described processing until the download end date and time obtained from schedule 606 (step S0006), and downloads the reserved download program (step S0007).

  In the above processing, the ECG storage unit 7205 performs all the electronic program guide generation / download program reservation execution processing. However, a control unit (not shown) that controls the entire broadcast receiving apparatus 7200 stores the ECG storage unit 7205 in the ECG storage unit 7205. An electronic program guide is created based on the information obtained from the accumulated ECG data, schedule 906 of download control information 905 is acquired and separately stored in a reservation storage unit (not shown), and a reservation storage unit (not shown). ), A download program reservation execution process may be performed according to the information.

Council for Information and Communication Consultation No. 2023 “Technical Conditions for Advanced Satellite Digital Broadcasting” of “Technical Conditions for Broadcasting Systems” Report of Ministry of Internal Affairs and Communications July 29, 2008, page 29

  By the way, the broadcast download broadcasting system currently under study is designed on the assumption that the same content is provided to all users in terms of programs. For this reason, there has been a problem that content that can be substantially handled is restricted. For this reason, there is a problem that the following problems (Problem 1) to (Problem 3) occur.

  (Problem 1) Different contents cannot be handled according to the attributes of the user and the receiver. Here, as the attribute, the area where the user is located, the user's preference, and the like can be considered. In other words, in detail, for example, local news programs and local weather information cannot be handled as content, and for products that are sold only in some areas, CMs are limited to the sales area. There is a problem that it is impossible to broadcast, and it is impossible to handle different contents for each user.

  (Problem 2) Content that requires high freshness could not be handled. Here, the content that requires high freshness is content that the user pays attention to, for example, data that changes from moment to moment, such as weather forecasts, traffic information, stocks and exchange rates. It can be said that such content has no value for the user unless it has a certain level of freshness. However, in download broadcasting, for example, contents accumulated several hours to several days ago may be handled, but there is a problem that it is essentially impossible to guarantee high freshness.

  (Problem 3) The content could not be changed after the content was accumulated. In download broadcasting, the timing for producing content and the timing for viewing the content by the user are separated in time, and the separated time difference is different for each user. For this reason, even if all or part of the content becomes inappropriate after a certain date and time, the content cannot be changed. Not being able to change is not only when the content production side is unpredictable and not noticed until it becomes inappropriate, but there is also a problem that it can not be done even if the invalid date is known in advance .

The broadcast receiving apparatus of the present invention includes a receiving unit that receives a download broadcast signal, a separation unit that separates video / audio data and download content information from the received download broadcast signal, and content that stores the separated video / audio data. Content that is stored in the storage unit, the content information storage unit that stores the separated download content information, and the content that is included in the download content information and that includes at least the content reference attribute, the expiration date attribute, and the alternative content reference attribute as well as specify includes a content reproduction controller for reproducing the content stored in the content storage unit, a communication unit to access the URL included in the playlist information, the content reproduction control unit in accordance with the expiration date attribute Whether the content reference attribute is valid If it is valid, the content specified by the content reference attribute is acquired via the communication unit and stored in the content storage unit. If not valid, the content specified by the alternative content reference attribute is stored in the communication unit. Is acquired and stored in the content storage unit, and after the content storage in the content storage unit is completed, it is determined whether or not the stored content is valid according to the expiration date attribute. Content specified by an attribute is acquired via a communication unit .

  According to the present invention, the following effects can be obtained with respect to the above (Problem 1) to (Problem 3).

  (Effect 1) Different contents can be handled according to the location and preferences of the user.

  (Effect 2) It is possible to handle content that requires high freshness. For example, data that changes from moment to moment, such as weather forecasts, traffic information, stocks and exchange rates, can be handled as download broadcast contents.

  (Effect 3) Part or all of the content can be changed after the content is stored. The content creation side can change not only when the date and time when the content is changed, but also when it is unpredictable in advance such as a natural disaster or scandal.

The figure which shows the structure of the broadcast transmission / reception system which concerns on Embodiment 1 of this invention. The figure which shows the data structure of the playlist based on the embodiment The flowchart which shows the content reproduction | regeneration processing using the playlist which concerns on the embodiment The figure which shows the structure of the conventional broadcast transmission / reception system The figure which shows the structure of the conventional reproduction | regeneration control information file The figure which shows the structure of the conventional ECG data file A flowchart showing download broadcast reservation execution processing in a conventional broadcast receiving apparatus

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram illustrating a configuration of a broadcast transmission / reception system 100 according to the first embodiment in which downloadable content can be changed in broadcast-type download broadcasting. In FIG. 1, the same components as those of the conventional broadcast transmission / reception system 400 described with reference to FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted as it is the same as the conventional broadcast transmission / reception system 400 unless otherwise specified. To do. FIG. 2 shows the configuration of a playlist 200 for realizing the first embodiment. The playlist is created in the ECG data generation unit 1101 and input to the TLV multiplexing unit 4107, and the TLV multiplexing unit 4107 sends out a TLV stream including the playlist 200 to the broadcast receiving apparatus 1200 via the transmission unit 4101. The playlist is realized by a method of expanding and storing the GI 601 of the ECG data file 600, a method of adding a completely new element to the EGC data file 600, or the like.

  FIG. 2 is a diagram showing a data structure of a playlist in the first embodiment of the present invention. In the figure, reference numeral 200 denotes the entire playlist, which is transmitted from the broadcast transmitting apparatus 1100 as described above.

  The playlist 200 includes a playlist element that is information for controlling reproduction of each content regarding a plurality of contents. FIG. 2 shows that the playlist 200 includes four playlist elements, that is, a playlist element 210, a playlist element 220, a playlist element 230, and a playlist element 240.

  Each playlist element is composed of a plurality of attributes. That is, the content reference attribute 201, the expiration date attribute 202, and the alternative content reference attribute 203 are included.

  Here, the content reference attribute 201 will be described. The content reference attribute 201 designates content associated with each playlist element. The content reference attribute 201 can be specified in a plurality of formats.

  For example, the content reference attribute 201 can specify accumulated content. The format of the identification information includes an ID such as a CRID determined on the transmission side, a URI (Uniform Resource Identifier) including parameters used when receiving content from the transmission side by broadcast or communication, DCI 605, and the broadcast reception device 1200. Any of the serial numbers assigned by being numbered in can be used.

  The content reference attribute 201 can specify a part of the accumulated content. In the identification information 221, a temporal part of the accumulated AV (video / audio) is designated. Alternatively, a part of the coordinate system may be selected from the screen, or a part of the coordinate system may be selected when a plurality of sounds are included at the same time.

  Alternatively, the content reference attribute 201 can hold a parameter for acquiring content by communication. The identification information 231 holds a URI that designates content in a server connected via a network.

  Furthermore, the content reference attribute 201 can configure a playlist having a recursive structure by designating another playlist. The content reference attribute 241 stores a URI for acquiring a playlist by communication.

  Note that video and audio may be designated separately. That is, the video is stored in advance by download broadcasting, and the audio may be acquired by communication. For example, a large-capacity video can be efficiently transmitted by download broadcasting, and a dubbing or interpreter that takes time to produce can be produced over time until after the video is transmitted, and then transmitted.

  Next, the expiration date attribute 202 will be described. The expiration date attribute 202 designates a period during which the content reference attribute 201 of the playlist element being noticed is valid. When the current time is not included in the valid period, the content reference attribute 201 is handled in the same manner as when nothing is specified. The expiration date attribute 212 of the playlist element 210 specifies that the identification information 211 as the content reference attribute 201 is valid until 12:00 on December 31, 2010. This attribute may include the date and time when the content reference is activated from the invalid state to the valid state, or a plurality of valid periods may be held simultaneously. In addition, the maximum time elapsed from the date and time when each user first viewed may be specified, or the number of reproducible times to be counted down at each reproduction may be stored. Alternatively, the expiration date 202 of the playlist element 220 and the expiration date attribute 202 of the playlist element 230 indicate a case where no time limit is specified. In this case, it is always effective regardless of the passage of time. In the above description, the evaluation method for the expiration date attribute 202 is determined based on whether or not the current time satisfies the condition, but other determination methods may be used. For example, the content version, the condition that the content is valid for a specific user, the battery state of the broadcast receiving apparatus 1200, the communication quality of the network, the conformity with user preference information, and the like may be stored.

  Next, the alternative content reference attribute 203 will be described. The alternative content reference attribute 203 specifies alternative content when it is determined that the content reference attribute 201 is invalid according to the expiration date attribute 202. Possible values of the alternative content reference attribute 203 may be the same as those of the content reference attribute 201. If the expiration date attribute 202 does not satisfy the expiration date in the playlist element being noticed, the content reference attribute 201 becomes invalid. At this time, if a valid value is stored in the alternative content reference attribute 203, the content specified by the alternative content reference attribute 203 is adopted as the content specified by the playlist element. In FIG. 2, one alternative content reference attribute is stored for one playlist element. However, a plurality of alternative attributes may be processed by storing a plurality of alternative content reference attributes.

  Next, processing in which the broadcast receiving apparatus 1200 reproduces content using the playlist 200 will be described with reference to FIG. FIG. 3 is a flowchart of playlist reproduction in the broadcast receiving device 1200 according to Embodiment 1 of the present invention. Here, it is assumed that the playlist 200 is stored in advance in the ECG storage unit 1201 via the reception unit 4201 and the TLV demultiplexing unit 4203.

  (Step S0301) The content reproduction control unit 1202 takes out the playlist elements pp from the designated playlist P one by one in order.

  (Step S0302) The content reproduction control unit 1202 executes the last step S0301, and if all the playlist elements pp have already been selected and nothing has been extracted as the playlist elements pp (“ yes "), the process ends.

  (Step S0303) The content reproduction control unit 1202 evaluates the expiration date attribute of the playlist element pp selected in step S0301. If it is determined that the content is valid, the content C to be reproduced is set as the value of the content reference attribute, and the process proceeds to step S0305. If it is determined that it is not valid, the process proceeds to step S0304.

  (Step S0304) The content reproduction control unit 1202 refers to the alternative content reference attribute of the playlist element pp, and changes the content C to be reproduced to one designated by the alternative content reference attribute. Then, the content reproduction control unit 1202 acquires the content C that is the alternative content from the distribution server 1300 via the communication unit 1203 and stores it in the content storage unit 1204. Then, the process proceeds to step S0305.

  (Step S0305) The content reproduction control unit 1202 proceeds to step S0307 if the format of the content C is a playlist, and proceeds to step S0306 if it is not a playlist.

  (Step S 0306) The content reproduction control unit 1202 reproduces the content C stored in the content storage unit 1204. Then, the process returns to step S0301.

  (Step S0307) The content reproduction control unit 1202 recursively calls the processing from step S0301 to step S0306 with the playlist C as an argument. By this processing, reproduction for the playlist C is realized. Then, the process returns to step S0301.

  Note that the user of the broadcast receiving apparatus 1200 may reproduce the playlist by the same operation as that performed when selecting and reproducing the content. Alternatively, one of the contents may be selected from a list screen in which content and playlists are mixed. With this selection method, from the user's point of view, the playlist can be operated as a single type of content without having to master a special operation method.

  Now, a process of playing back different contents depending on the region where it is located will be described. In the playlist element 230, content acquisition from communication is designated by the content reference attribute 201. In the server connected by communication, the content designated for each broadcast receiving device 1200 can be changed. For example, when the broadcast receiving device 1200 requests content acquisition through communication, if information on a region where the broadcast receiving device 1200 exists is sent, the server can select content appropriate for that region from a plurality of contents according to the information. Select and send back. Alternatively, the server identifies the broadcast receiving device by recognizing the route that the broadcast receiving device 1200 is accessing instead of directly transmitting the area information from the broadcast receiving device 1200, and then By using a correspondence table from the broadcast receiving apparatus to the area on the server side, it may be specified which area.

  In addition, by sending user preference information or the like instead of regional information, the server side may select content that matches the user preference.

  As described above, it is possible to replace some contents included in the playlist for each broadcast receiving device on the server side. For example, it is possible to change different contents for each region, such as each local version of the news program and the weather information of the region, for each region of the broadcast receiving apparatus. Alternatively, it is possible to broadcast a CM limited to a sales region for a product that has been sold only in some regions. Also, different contents can be handled for each user.

(Embodiment 2)
In the second embodiment, a method for guaranteeing the freshness of content will be described. First, as in the alternative content reference attribute 203, when playing a playlist, it is always necessary to obtain the latest content via communication. Although this method is simple, content acquisition by communication is indispensable when playing a playlist, so that the advantages of download broadcasting such as reduction of traffic and server load in the entire communication infrastructure are impaired.

  A method for solving the above problem will be described using the playlist element 210. In the playlist element 210, the accumulated content is specified by the content reference attribute 211. Then, a time limit that the freshness of the accumulated content is sufficient is stored in the expiration date attribute 212. If it is determined that the freshness of the content stored by the expiration date attribute 212 is insufficient when the playlist element 210 is reproduced, the content acquisition through communication is performed by the alternative content reference attribute 210. Since content is not acquired by communication within the expiration date, both the reduction of traffic and server load in the entire communication infrastructure and the guarantee of freshness of content are achieved at the same time.

  By introducing a mechanism that can guarantee the freshness of content as described above, it is possible to handle data that changes from moment to moment, such as weather forecasts, traffic information, stocks and exchange rates, as download broadcast content. .

(Embodiment 3)
In the third embodiment, a method of changing a part or all of content after content accumulation will be described.

  First, if communication acquisition is specified in the content reference attribute 201 so that the content is always acquired by communication, the playlist can be reproduced with the change as intended on the transmission side.

  Furthermore, if the playlist P2 is designated as the content acquired by communication like the playlist element 241, the number of content to be reproduced can be changed. The structure of the playlist P2 may be the same as the playlist described in FIG. For example, if content stored as a playlist element of the playlist P2 is specified, content having a large data size is not received by communication, and only data of the playlist P2 itself having a relatively small size is received. Good. Therefore, according to this method, it is possible to reduce traffic and server load in the entire communication infrastructure.

  According to the present invention, in a content delivery system in which distribution to a broadcast receiver and viewing timing of a user are performed asynchronously, such as broadcast-type download broadcasting, the content can be changed according to the region and preference. , The freshness of the content can be guaranteed or changed after accumulation. Therefore, it is useful for all AV devices that can receive download broadcasts.

DESCRIPTION OF SYMBOLS 100 Broadcast transmission / reception system 1100 Broadcast transmission apparatus 1101 ECG data generation part 1200 Broadcast reception apparatus 1201 ECG storage part 1202 Content reproduction control part 1203, 1301 Communication part 1204, 1302, 4104 Content storage part 1300 Distribution server 4101 Transmission part 4102 Video / audio encoding Unit 4103 EPG data generation unit 4106 MPEGTS multiplexing unit 4107 TLV multiplexing unit 4108 switching unit 4201 receiving unit 4202 MPEGTS demultiplexing unit 4203 TLV demultiplexing unit 4204 EPG accumulation unit 4207 video / audio switching unit 4208 video / audio processing unit 4209 video / audio output Part

Claims (1)

A receiving unit for receiving a download broadcast signal;
A separation unit for separating video / audio data and download content information from the received download broadcast signal;
A content storage unit for storing the separated video and audio data;
A content information storage unit for storing the separated download content information;
Content playback for specifying content to be played back based on playlist information included in the download content information and including at least a content reference attribute, an expiration date attribute, and an alternative content reference attribute, and playing back the content stored in the content storage unit A control unit;
A communication unit that accesses a URL included in the playlist information,
The content reproduction control unit determines whether or not the content reference attribute is valid according to the expiration date attribute, and if valid, acquires the content specified by the content reference attribute via the communication unit. If the content is not valid, the content specified by the alternative content reference attribute is acquired via the communication unit and stored in the content storage unit, and the content stored in the content storage unit is further stored. After the completion of the accumulation, it is determined according to the expiration date attribute whether the accumulated content is valid, and if not valid, the content specified by the alternative content reference attribute is acquired via the communication unit. Broadcast receiving device.

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