Patent Publication Number: US-11039212-B2

Title: Reception device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. application Ser. No. 15/893,177, filed Feb. 9, 2019, which is a continuation of U.S. application Ser. No. 15/038,516, filed May 23, 2016, which is a U.S. National Phase Application of International Application No. PCT/JP2014/080577, filed Nov. 19, 2014, which is based on and claims priority to Japanese Application No. 2013-250117, filed Dec. 3, 2013. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a reception device and, in particular, relates to a reception device that can select an optimal component. 
     BACKGROUND ART 
     Not only services using broadcast but also hybrid services in collaboration with communication has been introduced in the fields of digital broadcasting (for example, Patent Document 1). The components, such as a video component, an audio component, and a caption component, forming a service can be transmitted via broadcast or communication in such hybrid services. 
     CITATION LIST 
     
         
         Patent Document 1: Japanese Patent Application Laid-Open No. 2011-66556 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     It is assumed that the introduction of hybrid services makes the structure of the components forming a service complicated while enabling the provision of various services. However, a technical scheme for selecting the optimal component for each service is not established. 
     In the light of the foregoing, the present invention facilitates the selection of the optimal component for each service. 
     Solutions to Problems 
     A reception device according to an aspect of the present invention includes: a first reception unit that receives a component transmitted on a broadcast wave; a second reception unit that receives a component distributed via a network; and a control unit that controls operation of each unit, wherein the control unit selects an optimal component from a plurality of components that the reception device is able to receive. 
     The reception device can be an independent device or an internal block included in a device. 
     The reception device according to an aspect of the present invention receives a component transmitted on a broadcast wave, receives a component distributed via a network, and selects the optimal component from a plurality of component candidates that can be received. 
     Effects of the Invention 
     According to an aspect of the present invention, an optimal component can be selected. 
     The effects of the present invention are not limited to the effects described herein, and can be any one of the effects described herein. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram of a component layer structure. 
         FIG. 2  is a diagram of an exemplary structure of signaling information. 
         FIG. 3  is a diagram of a specific example of component layers. 
         FIG. 4  is a diagram of an exemplary screen layout. 
         FIG. 5  is a diagram of a specific example of audio component layers. 
         FIG. 6  is a diagram of a specific example of audio component layers. 
         FIG. 7  is a diagram of a specific example of audio component layers. 
         FIG. 8  is a diagram of a specific example of audio component layers. 
         FIG. 9  is a diagram of the configuration of an embodiment of a broadcast communication system using the present invention. 
         FIG. 10  is a diagram of the configuration of an embodiment of a transmission device using the present invention. 
         FIG. 11  is a diagram of the configuration of an embodiment of a distribution server using the present invention. 
         FIG. 12  is a diagram of the configuration of an embodiment of a reception device using the present invention. 
         FIG. 13  is an explanatory flowchart of a transmission process. 
         FIG. 14  is an explanatory flowchart of a distribution process. 
         FIG. 15  is an explanatory flowchart of a reception process. 
         FIG. 16  is a diagram of an exemplary configuration of a computer. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     The embodiments of the present invention will be described hereinafter with reference to the appended drawings. Note that the embodiments will be described in the following order. 
     1. Component Structure 
     2. System Configuration 
     3. Flow of Process Performed in Each Device 
     4. Specific Example of Operation 
     5. Computer Configuration 
     1. Component Structure 
     Component Layer Structure 
       FIG. 1  is a diagram of a component layer structure. 
     As illustrated in  FIG. 1 , each of a video component (Video), an audio component (Audio), and a caption component (Caption) includes three layers, a selective layer (Selective Layer), a composite layer (Composite Layer), and an adaptive layer (Adaptive Layer). In the layer structure, the composite layer is placed as the upper layer of the adaptive layer, and the selective layer is placed as the upper layer of the composite layer. The details of each layer will be described in order hereinafter. 
     Adaptive Layer 
     The adaptive layer will be described first. As illustrated in  FIG. 1 , one of circular symbols with different patterns indicates a component transmitted on a broadcast wave (Broadcast Component), and the other circular symbol indicates a component distributed via a network (Broadband Component) on the adaptive layer that is the lowest layer. These components are distributed as so-called adaptive streaming, and a plurality of components at different bit rates is prepared. A broadcast component is prepared for each category in the example of  FIG. 1 . Note that, however, a plurality of broadcast components can be prepared. Furthermore, the classification of the video component, the audio component, and the caption component is herein referred to as a category (CATEGORY). 
     A line that swings right and left on a dotted arc in the drawing functions as a switch in the adaptive layer. This selects a component from the components. In other words, the adaptive layer is a layer for dynamically switching the components in accordance with the adaptive determination by the receiver in each of the component categories and causing the components to function as a component. Note that, when there is only a component, the component is constantly selected without the selection with the switch. 
     The transmission channel or bit rate of the components can be designated as the attribute of the components to be adaptively selected in the adaptive layer. For example, broadcast or communication is designated as the attribute value of the transmission channel. For example, 10 Mbps is designated as the bit rate. For example, an attribute about screen resolution or robustness of a physical layer (PHY) can be designated. Note that the attributes of the components to be adaptively selected are examples and another attribute can be designated. 
     The attribute can be designated as described above. This enables the receiver to implement adaptive streaming distribution by switching the components and adaptively selecting the optimal component every predetermined period (for example, every 10 seconds). Specifically, when the transmission channel of the component is only communication, the component at the optimal bit rate can be selected in response to the occupation of a reception buffer (for example, a reception buffer  421  to be described below with reference to  FIG. 12 ) in the receiver and the occupation varies depending on the congestion of the communication channel. 
     Alternatively, when the transmission channel of the component includes also broadcast in addition to communication, the selection between the communication component and the broadcast component can be determined in accordance with the bit rate of the broadcast component. For example, it is assumed in this example that components at 1 Mbps, 2 Mbps, 5 Mbps, 10 Mbps, and 20 Mbps are prepared as the components to be distributed via the network, and only a component at 8 Mbps is prepared as the component to be transmitted on a broadcast wave. 
     When the receiver can receive the communication components at 10 and 20 Mbps, the bit rate is higher than the bit rate of the broadcast component in this example. Thus, the receiver preferentially receives the communication components. When it is difficult to receive the communication components at 10 and 20 Mbps due to congestion and the receiver can receive the communication component at 5 Mbps, the receiver can select the broadcast component at 8 Mbps that the receiver can stably receive instead of the communication components. Note that, when a plurality of broadcast components is prepared, for example, the variations in Carrier/Noise (C/N) of the broadcast signal are measured and the broadcast components can adaptively be switched in response to the result from the measurement. 
     Composite Layer 
     The composite layer will be described next. As illustrated in  FIG. 1 , the components adaptively selected in the adaptive layer are synthesized as a component in the composite layer that is the upper layer of the adaptive layer. In other words, the composite layer is a layer for combining the components in a group of the components to be synthesized (hereinafter, referred to as a “composite component group”) and causing the synthesized components to function as a component (synthesized component) in each component category. Note that, when there is only a component in a group of the components to be synthesized, the synthesizing operation is unnecessary. 
     For example, “scalable”, “three-dimensional image (3D)”, “tile”, “layer”, and “mixing” can be designated as the attribute of the components to be synthesized in the composite layer. Each of the attributes indicates a type of combination of the components, and an attribute value indicating the element of the combination can be designated. 
     The “scalable” is an attribute indicating that the component to be synthesized is a component encoded in scalable coding. “Base” or “Extended” is designated as the attribute value of the “scalable” attribute. 
     For example, in order to provide an image at 4K resolution, an encoded signal (video component) corresponding to an image at 2K resolution for which “Base” is designated as the attribute value of the “scalable” attribute is transmitted on a broadcast wave. Meanwhile, an encoded image signal (video component) corresponding to the difference between the image at 4K resolution and the image at 2K resolution is distributed via the network while “Extended” is designated as the attribute value of the “scalable” attribute. Thus, a receiver compatible with 4K resolution can synthesize the base stream (Base Stream) transmitted via broadcast and the extended stream (Extended Stream) transmitted via communication, and display the image at 4K resolution. On the other hand, a receiver that is not compatible with 4K resolution displays the image at 2K resolution using the base stream transmitted via broadcast. 
     The “3D” is an attribute indicating that the component to be synthesized is a component for a 3D image. “Right” or “Left” is designated as the attribute value of the “3D” attribute. For example, the signal of a right-eye image (video component) for which “Right” is designated as the attribute value of the “3D” attribute is transmitted on a broadcast wave. Meanwhile, the signal of a left-eye image (video component) for which “Left” is designated as the attribute value of the “3D” attribute is distributed via the network. Thus, a receiver compatible with a 3D image can synthesize the right-eye image signal and the left-eye image signal, and display the 3D image. 
     The “tile” is an attribute indicating that the component to be synthesized is a tiled component. For example, “TileA1”, “TileA2”, “TileB1”, “TileB2”, . . . , or “TileC1”, “TileC2”, . . . are designated as the attribute value of the “tile” attribute. 
     For example, the “TileA” of the “TileA1”, “TileA2”, . . . indicates that the type of the tiling is a type A. When the tiling type A is a scheme in which two tiled images are arranged right and left and displayed, the signal of the tiled image (video component) for which “TileA1” is designated as the attribute value of the “tile” attribute and which is to be arranged on the left side is transmitted on a broadcast wave, and the signal of the tiled image (video component) for which “TileA2” is designated as the attribute value of the “tile” attribute and which is to be arranged on the right side is distributed via the network. Thus, a receiver compatible with tiling display can synthesize the left-tiled image signal and the right-tiled image signal, and display an image in accordance with the tiling type A. 
     Similarly, for example, when a tiling type B is a scheme in which four tiled images are arranged two by two and displayed, the signals for the four tiled images (video components) are transmitted via broadcast or communication. Thus, a receiver can synthesize the tiled images, and display the two by two images in accordance with the tiling type B. For example, when a tiling type C is a scheme in which a plurality of tiled images is arranged as a panoramic image (for example, 360 degrees) and displayed, the signals of the tiled images (video components) are transmitted via broadcast or communication. Thus, a receiver can synthesize the tiled image signals, and display the panoramic image in accordance with the tiling type C. Note that the types A to C of the tiling schemes are examples, and another tiling scheme can be used. 
     The “layer” is an attribute indicating that the component to be synthesized is a component layer displayed as a layer. “Layer1”, “Layer2”, . . . are designated as the attribute value of the “layer” attribute, for example, in the layering order from the lowest layer. For example, the signal of the first-layer image (video component) for which “Layer1” is designated as the attribute value of the “layer” attribute is transmitted on a broadcast wave. Meanwhile, the signal of the second-layer image (video component) for which “Layer2” is designated as the attribute value of the “layer” attribute is distributed via the network. Thus, a receiver compatible with layer display can synthesize the first-layer image signal and the second-layer image signal, and display an image that the second-layer image is layered on the first-layer image. 
     The “mixing” is an attribute indicating that the component to be synthesized is a component to be mixed. For example, “Track1”, “Track2”, . . . are designated as the attribute value of the “mixing” attribute. For example, a voice track (audio component) for which “Track1” is designated as the attribute value of the “mixing” attribute is transmitted on a broadcast wave. Meanwhile, a voice track (audio component) for which “Track2” is designated as the attribute value of the “mixing” attribute is distributed via the network. Thus, a receiver compatible with mixing can mix the voice track 1 and the voice track 2 (for example, adjust the volume relative positions or the panning position), and output the mixed voice. 
     Note that the attributes of the components to be synthesized in the composite layer and the attribute values are examples, and another attribute and another attribute value can be designated. 
     Selective Layer 
     The selective layer will be described last. As illustrated in  FIG. 1 , a line that swings right and left on a dotted arc in the drawing functions as a switch, and a component is selected from a plurality of components in the selective layer that is the upper layer of the composite layer and the highest layer. In other words, the selective layer is a layer for statically selecting one or a plurality of components in a group of the components to be statically selected (hereinafter, referred to as a “selective component group”) in each component category in accordance with a predetermined selection method. A method in which the user selects the components or a method in which the receiver automatically selects the components in accordance with the throughput of the receiver or the information about the user&#39;s taste can be used as the selection method. 
     For example, “view tag”, “language”, “required receiver throughput”, “view title”, or “purpose” can be designated as the attribute of the components to be statically selected in the selective layer. 
     Specifically, the “view tag” is a tag for combining the different component categories included in a view. For example, when “1” is designated as the “view tag”, the video component, audio component, and caption component to which ID “1” is added are selected across the categories. Similarly, when “2” is designated as the “view tag”, the components to which ID “2” is added are selected across the categories. Note that the component to which a view tag is not added is independent in each category. 
     For example, a language code is designated as the “language”. For example, a Graphical User Interface (GUI) screen corresponding to the language code is displayed and the user selects the desired language. The throughput required to the receiver is designated as the “required receiver throughput”. The required throughput can be designated, for example, with a level value, or codec and resolution can be designated in multiple dimensions. For example, when the required throughput is designated with a level value and a level 2 is designated as the level value, only the receiver with a throughput at the level 2 or higher can be used. 
     A title for selecting a view screen is designated as the “view title”. For example, the view title is displayed in a text format, and the user selects the desired view screen. The information about the purpose of the component, for example, the narration voice for the main voice is designated as the “purpose”. 
     Note that the attributes of the components to be statically selected in the selective layer are examples and another attribute can be selected. Furthermore, not only an attribute is used as the attribute of the components to be statically selected, and the combination of a plurality of attributes can be used. 
     The attributes of the components to be statically selected can be designated as described above. Thus, the application running in a receiver can select the component in accordance with the attribute of the components to be statically selected. However, when there is only a selective component group, the selection is unnecessary and the selective component group is selected. For example, when the video component, audio component, and caption component in the different categories are combined and grouped with a view tag, the components are selected in a unit of the group. 
     When the receiver selects a plurality of components from the video components and caption components, a plurality of image and caption screens is displayed. Alternatively, when the receiver selects a plurality of components only form the audio components, the voices are mixed (in Mixing) and are output. 
     A selective layer exists in each component category in the exemplary component layer structure of  FIG. 1 . Note that, however, a plurality of selective layers can exist in each component category. Furthermore, the video component, audio component, and caption component are described as the components in the component layer structure of  FIG. 1 . However, a similar layer structure can be used for another component included in a service. 
     Exemplary Signaling Information Structure 
       FIG. 2  is a diagram of an exemplary structure of the signaling information (the control signal) for implementing the component layer structure illustrated in  FIG. 1 . Note that  FIG. 2  illustrates elements and attributes and “@” is attached to the attribute. Each of the indented elements and attributes is designated for the upper element of the indented elements. 
     As illustrated in  FIG. 2 , the “topAttribute” attribute is an attribute for the final selection and is defined with m0 types (m0=1, . . . , m0). For example, the selection number and the selection determination are defined as the “topAttribute” attribute. The total number of components to be selected is designated as the selection number. The selection by the user or automatic selection by the receiver is selected as the selection determination. 
     The information about a selective component group that is the component group to be statically selected is designated as the “SelectiveComponentGroup” element. The “SelectiveComponentGroup” element is the upper element of the “CompositeComponentGroup” element. Note that the frequency of appearance of the “SelectiveComponentGroup” is n1 (n1=1, . . . , n1). 
     The “selectiveAttribute” attribute indicates a plurality of attributes prescribed for the “SelectiveComponentGroup” element. The attribute of the components to be statically selected is prescribed with m1 types (m1=0, . . . , m1). For example, an individual attribute such as “view tag”, “language”, “required receiver throughput”, “view title”, or “purpose” is prescribed as the attribute of the components to be statically selected in the selective layer for the “selectiveAttribute” attribute. 
     The information about the composite component group that is a component group to be synthesized is designated as the “CompositeComponentGroup” element. The “CompositeComponentGroup” element is the upper element of the “AdaptiveComponent” element. Note that the frequency of appearance of the “CompositeComponentGroup” element is n2 (n2=1, . . . , n2). 
     The “compositeAttribute” attribute indicates a plurality of attributes prescribed for the “CompositeComponentGroup” element, and the attribute of the components to be synthesized is prescribed with m2 types (m2=0, . . . , m2). For example, an individual attribute such as “scalable”, “3D”, “tile”, “layer”, or “mixing” is prescribed as attribute of the components to be synthesized in the composite layer for the “compositeAttribute” attribute. The attributes indicate a type of combination of the components, and the attribute values indicating the elements in the combination can be designated. 
     The information about the component to be adaptively selected is designated as the “AdaptiveComponent” element. Note that the frequency of appearance of the “AdaptiveComponent” element is n3 (n3=1, . . . , n3). 
     The “adaptiveAttrbute” attribute indicates a plurality of attributes prescribed for the “AdaptiveComponent” element and the attribute of the components to be adaptively selected is prescribed with m3 types (m3=0, . . . , m3). For example, the transmission channel or bit rate of the component is individually prescribed as the attribute of the components to be adaptively selected in the adaptive layer for the “adaptiveAttrbute” attribute. The ID of the component is designated as the “componentId” attribute. 
     Note that the data structure of the signaling information for implementing the component layer structure in  FIG. 1  described with reference to  FIG. 2  is an example, and another data structure can be used. The signaling information is written in a markup language such as Extensible Markup Language (XML). 
     Specific Example of the Component Layer 
     A specific example of the component layer will be described with reference to  FIGS. 3 to 8 . 
     In a specific example of the component layer in  FIG. 3 , the “scalable” is designated as the attribute of the components to be synthesized in the video composite layer (Composite Layer). A base stream (“Scalable Base” in the drawing) is transmitted via broadcast and an extended stream (“Scalable Extended” in the drawing) is transmitted via communication in the adaptive layer (Adaptive Layer) that is the lower layer of the Composite Layer. In this example, only a broadcast video component to be adaptively selected is prepared as the base stream and thus the broadcast video component is constantly selected. On the other hand, a plurality of communication video components to be adaptively selected is prepared as the extended stream, and thus the optimal video component is adaptively selected from the communication video components (“Adaptive switching” in the drawing). 
     To provide an image at 4K resolution, the encoded image signal (video component) at 2K resolution transmitted via broadcast, and the encoded image signal (video component) corresponding to the difference between the image at 4K resolution and the image at 2K resolution transmitted via communication are synthesized in the video composite layer. When, for example, the “required receiver throughput” is designated as the attribute of the components to be statically selected in the selective layer (Selective Layer) and a receiver is compatible with 4K resolution, the receiver can display the synthesized image at 4K resolution (“4K Capable Main View” in the drawing). On the other hand, when the receiver is not compatible with 4K resolution, the receiver uses only the base stream transmitted via broadcast to display the image at 2K resolution (“4K Disable Main View” in the drawing). In other words, the communication video component is not used and thus the adaptive selection of the video component is not performed in this case (“Non switching” in the drawing). 
     As illustrated in  FIG. 4 , the main view (Main View) means the main display area in the display screen in this example. The image at 4K resolution or 2K resolution is displayed on the main view. A sub-view (Sub View) that is an auxiliary display area relative to the main display area can be displayed on the exemplary screen in  FIG. 4 . A sub-view  1  (“Sub View 1 ” in the drawing) and a sub-view  2  (“Sub View 2 ” in the drawing) can be selected as the selective component group in the selective layer in the exemplary component layer in  FIG. 3 . 
     Only a communication video component is prepared for the sub-view  1  in the adaptive layer. Thus, the adaptive selection is not performed and the communication video component is constantly selected (“Non switching” in the drawing). A plurality of communication video components to be adaptively selected is prepared for the sub-view  2  in the adaptive layer, and thus the optimal communication video component is adaptively selected from the communication video components as necessary (“Adaptive switching” in the drawing). Although the sub-view  1  is displayed together with the main view in the exemplary screen in  FIG. 4 , the user can select which view, the main view, the sub-view  1 , or the sub-view  2  is displayed, for example, using the GUI screen. 
     With reference to  FIG. 3  again, the “scalable” is designated as the attribute of the components to be synthesized in the audio composite layer (Composite Layer). A stereophonic stream is transmitted via broadcast or communication (“Stereo” in the drawing) and a multi-channel stream (“Multi-channel Dev” in the drawing) is transmitted via communication in the adaptive layer (Adaptive Layer) that is the lower layer of the audio composite layer. 
     A plurality of audio components to be adaptively selected is prepared as the stereophonic stream, and thus the optimal audio component is adaptively selected from the broadcast or communication audio components (“Adaptive switching” in the drawing) in this example. In other words, the audio component with a normal robustness (“Normal Robustness” in the drawing) and the audio component with a high robustness (“High Robustness” in the drawing) are prepared as the broadcast audio components and one of the audio components can adaptively be selected. This enables the operation, for example, in which only the voice is output when the audio component with a high robustness is selected and it is difficult due to a reason to display the image on the receiver. When it is difficult to receive the broadcast audio component, the communication audio component can be selected. 
     On the other hand, only an audio component to be adaptively selected is prepared as the multi-channel stream, and thus the communication audio component is constantly selected. 
     The stereophonic audio component transmitted via broadcast and the multi-channel audio component transmitted via communication are synthesized and a synthesized 22.2 multi-channel component is generated in the audio composite layer. When, for example, the “required receiver throughput” is designated as the attribute of the components to be statically selected in the selective layer (Selective Layer) and the receiver is compatible with 22.2 multiple channels, the receiver can output the synthesized 22.2 multi-channel voice (“22.2ch Capable Main View” in the drawing). On the other hand, when the receiver is not compatible with 22.2 multiple channels, the receiver outputs the stereophonic voice using only the stereophonic stream transmitted via broadcast or communication (“22.2ch Disable Main View” in the drawing). 
     The view tag 1 is added to the audio components as the attribute of the components to be statically selected in the audio selective layer in this example. The audio components cooperate with the video components to which the view tag 1 is similarly added in the video selective layer. In other words, the voice corresponding to the audio components is output for the image displayed on the main view of the exemplary screen in  FIG. 4 . 
     The audio component to which the view tag 2 is added as the attribute of the components to be statically selected in the selective layer cooperates with the video component to which the view tag 2 is similarly added in the video selective layer (“Sub View 1 ” in the drawing). In other words, the voice corresponding to the audio components is output for the image displayed on the sub-view  1  of the exemplary screen in  FIG. 4 . 
     The audio component to which the view tag 3 is added as the attribute of the components to be statically selected in the selective layer cooperates with the video component to which the view tag 3 is similarly added in the video selective layer (“Sub View 2 ” in the drawing). Note that only a communication audio component is prepared for each of the audio sub-view  1  and the audio sub-view  2  in the adaptive layer. Thus, the adaptive selection is not performed, and the communication audio component is constantly selected. 
     As illustrated in  FIG. 3 , the synthesis of the caption components is not performed in the caption composite layer (Composite Layer) and the adaptive selection of the caption components is also not performed in the adaptive layer (Adaptive Layer). Thus, the caption components in the selective layer (Selective Layer) and the caption components in the adaptive layer correspond, respectively, one by one. Note that only the leftmost caption component among the caption components in the drawings is transmitted via broadcast, and the other caption components are transmitted via communication. 
     The caption components to which the view tag 1 is added as the attribute of the components to be statically selected in the selective layer cooperate with the video components and audio components to which the view tag 1 is similarly added. Specifically, the English caption and the Spanish caption are provided in this example. Not only the main captions (“Eng(Nor)” and “Spa(Nor)” in the drawing) but also more detailed explanatory captions (“Eng(Ex)” and “Spa(Ex)” in the drawing) are prepared for the captions. When “language” is designated as the attribute of the components to be statically selected in the caption selective layer by the user&#39;s selection, the caption in accordance with, for example, the language code of the selected language can be displayed. In other words, the caption of English or Spanish selected by the user is superimposed and displayed on the image displayed on the main view of the exemplary screen in  FIG. 4 . 
     The caption components to which the view tag 2 is added as the attribute of the components to be statically selected in the selective layer cooperate with the video component and audio component to which the view tag 2 is similarly added. Specifically, the English caption (“Eng” in the drawing) and the Spanish caption (“Spa” in the drawing) are prepared. Thus, the caption in response to the user&#39;s selection can be superimposed and displayed on the image displayed on the sub-view  1  of the exemplary screen in  FIG. 4 . 
     The caption components to which the view tag 3 is added as the attribute of the components to be statically selected in the selective layer cooperate with the video component and audio component to which the view tag 3 is similarly added. Specifically, the English caption (“Eng” in the drawing) and the Spanish caption (“Spa” in the drawing) are prepared. Thus, the caption in response to the user&#39;s selection can be superimposed and displayed on an image. 
     Another Specific Example of the Audio Component Layer 
     Another specific example of the audio component layer will be described next with reference to  FIGS. 5 to 8 . 
     As illustrated in  FIG. 5 , for example, a complete version (“Complete Main” in the drawing) or a mixed version (“Tracks to be Mixed” in the drawing) can be designated as the attribute value in the audio selective layer (Selective Layer). 
     Thus, for example, when the complete version is designated as the attribute value, a complete audio component is provided and the voice corresponding to the audio component is output. Note that a broadcast audio component at a high bit rate and a communication audio component at a low bit rate are prepared as the complete audio stream so that the optimal audio component is adaptively selected (“Adaptive switching” in the drawing). 
     Alternatively, for example, when the mixed version is designated as the attribute value, a music component (“Music” in the drawing), a dialog component (“Dialog” in the drawing), and an effect component (“Effect” in the drawing) are provided and synthesized so that the voice corresponding to the synthesized component is output. Note that the communication audio components at high and low bit rates are prepared as the music stream so that the optimal audio component is adaptively selected (“Adaptive switching” in the drawing). 
     Note that only a plurality of audio components for the mixed version can be provided without providing an audio component for the complete version as illustrated in  FIGS. 6 and 7 . In this example, a plurality of components at different bit rates can be prepared not only for the music stream but also for the dialog stream or the effect stream so that the optimal component can adaptively be selected. 
     As illustrated in  FIG. 8 , for example, the English version (“Main Eng Audio” in the drawing) or the Spanish version (“Main Spa Audio” in the drawing) can be designated as the attribute value of the “language” attribute in the audio selective layer (SELECTIVE LAYER). 
     Thus, for example, when the English version is designated as the attribute value, the dialog component (“Dialog” in the drawing), the effect component (“Effect” in the drawing), and the music component (“Music” in the drawing) are provided and synthesized so that the English voice corresponding to the synthesized component is output. Note that the broadcast component at a high bit rate and the communication component at a low bit rate are prepared as the dialog stream so that the optimal component is adaptively selected (“Adaptive switching” in the drawing). The communication components at high and low bit rates are prepared for the music stream so that the optimal component is adaptively selected (“Adaptive switching” in the drawing). 
     For example, when the Spanish version is designated as the attribute value, only an audio component is prepared as the audio stream for the Spanish version. Thus, the audio component is provided and the Spanish voice is output. 
     2. System Configuration 
     Configuration of the Broadcast Communication System 
       FIG. 9  is a diagram of the configuration of an embodiment of the broadcast communication system using the present invention. 
     As illustrated in  FIG. 9 , a broadcast communication system  1  includes a data providing server  10 , a transmission device  20 , a distribution server  30 , and a reception device  40 . The distribution server  30  and the reception device  40  are connected to each other via a network  90  such as the Internet. 
     The data providing server  10  provides various components such as a video component, an audio component, and a caption component to the transmission device  20  and the distribution server  30 . In this example, the data providing server  10  provides a video component at 8 Mbps to the transmission device  20 , and video components at 1 Mbps, 2 Mbps, 5 Mbps, 10 Mbps, and 20 Mbps to the distribution server  30 , respectively, as the components forming a television program in order to implement adaptive streaming distribution in a service, for example, providing the television program. 
     The transmission device  20  transmits the various components provided from the data providing server  10  (for example, the video component at 8 Mbps) using a broadcast wave of digital broadcasting. The transmission device  20  transmits also the control signal (the signaling information in  FIG. 2 ) together with the component using a broadcast wave of digital broadcasting. Note that the control signal (the signaling information in  FIG. 2 ) can be distributed, for example, from a dedicated server connected to the network  90 . 
     The distribution server  30  distributes various components provided from the data providing server  10  (for example, the video components at 1 Mbps, 2 Mbps, 5 Mbps, 10 Mbps, and 20 Mbps) to the reception device  40  via the network  90  in response to the request from the reception device  40 . 
     The reception device  40  receives the broadcast signal transmitted from the transmission device  20  and obtains the control signal (the signaling information in  FIG. 2 ). The reception device  40  obtains various components such as a video component, an audio component, and a caption component transmitted from the transmission device  20  (for example, the video component at 8 Mbps) in accordance with the control signal. The reception device  40  obtains various components such as a video component, an audio component, and a caption component distributed from the distribution server  30  (for example, the video components at 1 Mbps, 2 Mbps, 5 Mbps, 10 Mbps, and 20 Mbps) in accordance with the control signal. 
     The reception device  40  displays the image of the video component and the caption component on the display, and outputs the voice of the audio component in synchronization with the image from a loudspeaker. In this example, the optimal video component is adaptively selected and switched among the broadcast video component at 8 Mbps, and the communication video components at 1 Mbps, 2 Mbps, 5 Mbps, 10 Mbps, and 20 Mbps, for example, every predetermined period (for example, every 10 seconds). This implements the adaptive streaming distribution. 
     Note that the reception device  40  can be a single device including a display and a loudspeaker, or can be embedded, for example, in a television receiver or a video recorder. 
     The broadcast communication system  1  has the configuration described above. The detailed configuration of each device included in the broadcast communication system  1  in  FIG. 9  will be described next. 
     Configuration of the Transmission Device 
       FIG. 10  is a diagram of the configuration of an embodiment of the transmission device using the present invention. 
     As illustrated in  FIG. 10 , the transmission device  20  includes a component obtaining unit  201 , a control signal obtaining unit  202 , an Mux  203 , and a transmission unit  204 . 
     The component obtaining unit  201  obtains various components from the data providing server  10  and provides the components to the Mux  203 . 
     The control signal obtaining unit  202  obtains the control signal (the signaling information in  FIG. 2 ) from an external server such as the data providing server  10  or a built-in storage and provides the control signal to the Mux  203 . 
     The Mux  203  multiplexes the various components from the component obtaining unit  201  and the control signal from the control signal obtaining unit  202  to generate a transport stream and provides the transport stream to the transmission unit  204 . 
     The transmission unit  204  transmits the transport stream provided from the Mux  203  as a broadcast signal to the antenna  205 . 
     Configuration of the Distribution Server 
       FIG. 11  is a diagram of the configuration of an embodiment of the distribution server using the present invention. 
     As illustrated in  FIG. 11 , the distribution server  30  includes a control unit  301 , a component obtaining unit  302 , an accumulation unit  303 , and a communication unit  304 . 
     The control unit  301  controls the operation of each unit in the distribution server  30 . 
     The component obtaining unit  302  obtains various components from the data providing server  10  and provides the components to the control unit  301 . The control unit  301  accumulates the various components from the component obtaining unit  302  in the accumulation unit  303 . Thus, the various components from the data providing server  10  accumulate in the accumulation unit  303 . 
     The communication unit  304  exchanges various types of data with the reception device  40  via the network  90  in accordance with the control by the control unit  301 . 
     When the communication unit  304  receives a request for distribution of a stream (component) from the reception device  40 , the control unit  301  reads the requested component from the accumulation unit  303 . The control unit  301  controls the communication unit  304  to distribute the stream including the component read from the accumulation unit  303  to the reception device  40  via the network  90 . 
     Configuration of the Reception Device 
       FIG. 12  is a diagram of the configuration of an embodiment of the reception device using the present invention. 
     As illustrated in  FIG. 12 , the reception device  40  includes a tuner  402 , a Demux  403 , a selection and synthesis unit  404 , a selection and synthesis unit  405 , a selection and synthesis unit  406 , a control unit  407 , an NVRAM  408 , an input unit  409 , a communication unit  410 , a Demux  411 , a video decoder  412 , a video output unit  413 , an audio decoder  414 , an audio output unit  415 , and a caption decoder  416 . 
     The tuner  402  extracts the broadcast signal on the channel of the selected service from the broadcast signals received from the antenna  401  to demodulate the extracted signal, and provides a transport stream obtained from the demodulated signal to the Demux  403 . 
     The Demux  403  separates the transport stream provided from the tuner  402  into the components and the control signal, and provides the components to the selection and synthesis units  404  to  406  and provides the control signal to the control unit  407 . In this example, the components are separated into a video component, an audio component, and a caption component and are provided to the selection and synthesis unit  404 , the selection and synthesis unit  405 , and the selection and synthesis unit  406 , respectively. 
     The control unit  407  controls the operation of each unit in the reception device  40 . The NVRAM  408  is a non-volatile memory, and records various types of data in accordance with the control by the control unit  407 . The control unit  407  controls the selection and synthesis process performed by the selection and synthesis units  404  to  406  in accordance with the control signal (the signaling information in  FIG. 2 ) provided from the Demux  403 . 
     The input unit  409  provides an operation signal corresponding to the user operation to the control unit  407 . The control unit  407  controls the operation of each unit in the reception device  40  in accordance with the operation signal from the input unit  409 . 
     The communication unit  410  exchanges various types of data with the distribution server  30  via the network  90  in accordance with the control by the control unit  407 . The communication unit  410  provides the stream received from the distribution server  30  to the Demux  411 . At that time, the communication unit  410  receives the stream distributed from the distribution server  30  while buffering the stream data in a reception buffer  421  provided in the communication unit  410 . 
     The Demux  411  separates the stream provided from the communication unit  410  into components and provides the separated components to the selection and synthesis units  404  to  406 . In this example, the video component is provided to the selection and synthesis unit  404 , the audio component is provided to the selection and synthesis unit  405 , and the caption component is provided to the selection and synthesis unit  406 , respectively, after the stream is separated into the components. 
     The selection and synthesis unit  404  selects and synthesizes the video component from the Demux  403  and the video component from the Demux  411  in a selection and synthesis process (for example, the process performed in each layer of the video component layers in  FIG. 1 ) in accordance with the control by the control unit  407 . Then, the selection and synthesis unit  404  provides the video component obtained from the process to the video decoder  412 . 
     The video decoder  412  decodes the video component provided from the selection and synthesis unit  404 , and provides the video data obtained from the decoding to the video output unit  413 . The video output unit  413  outputs the video data provided from the video decoder  412  to the downstream display (not illustrated). This output displays, for example, the image of a television program on the display. 
     The selection and synthesis unit  405  selects and synthesizes the audio component from the Demux  403  and the audio component from the Demux  411  in a selection and synthesis process (for example, the process performed in each layer of the audio component layers in  FIG. 1 ) in accordance with the control by the control unit  407 . Then, the selection and synthesis unit  405  provides the audio component obtained from the process to the audio decoder  414 . 
     The audio decoder  414  decodes the audio component provided from the selection and synthesis unit  405 , and provides the audio data obtained from the decoding to the audio output unit  415 . The audio output unit  415  outputs the audio data provided from the audio decoder  414  to the downstream loudspeaker (not illustrated). This outputs the voice, for example, corresponding to the image of a television program from the loudspeaker. 
     The selection and synthesis unit  406  selects and synthesizes the caption component from the Demux  403  and the caption component from the Demux  411  in a selection and synthesis process (for example, the process performed in each layer of the caption component layers in  FIG. 1 ) in accordance with the control by the control unit  407 . Then, the selection and synthesis unit  406  provides the caption component obtained from the process to the caption decoder  416 . 
     The caption decoder  416  decodes the caption component provided from the selection and synthesis unit  406 , and provides the caption data obtained from the decoding to the video output unit  413 . When the caption decoder  416  provides the caption data to the video output unit  413 , the video output unit  413  synthesizes the caption data with the video data from the video decoder  412  and provides the synthesized data to the downstream display (not illustrated). This displays the caption corresponding to the image of a television program together with the image on the display. 
     The selection and synthesis units  404  to  406  are provided on the upstream side of each decoder in the reception device  40  in  FIG. 12  for the sake of description. Note that, however, the selection and synthesis units  404  to  406  can be provided on the downstream side of each decoder depending on the contents of the selection and synthesis process. 
     3. The Flow of the Process that Each Device Performs 
     The flow of the process that each device included in the broadcast communication system  1  in  FIG. 9  performs will be described next with reference to the flowcharts in  FIGS. 13 to 15 . 
     Transmission Process 
     The transmission process that the transmission device  20  in  FIG. 9  performs will be described with reference to the flowchart in  FIG. 13 . 
     In step S 201 , the component obtaining unit  201  obtains various components from the data providing server  10  and provides the components to the Mux  203 . 
     In step S 202 , the control signal obtaining unit  202  obtains the control signal (the signaling information in  FIG. 2 ), for example, from an external server and provides the control signal to the Mux  203 . 
     In step S 203 , the Mux  203  multiplexes the various components from the component obtaining unit  201  and the control signal from the control signal obtaining unit  202  to generate a transport stream, and provides the transport stream to the transmission unit  204 . 
     In step S 204 , the transmission unit  204  transmits the transport stream provided from the Mux  203  as a broadcast signal via the antenna  205 . When the process in step S 204  is completed, the transmission process in  FIG. 13  is completed. 
     The transmission process has been described above. In the transmission process, the various components provided from the data providing server  10  and the control signal are transmitted on a broadcast wave. 
     Distribution Process 
     The distribution process that the distribution server  30  in  FIG. 9  performs will be described with reference to the flowchart in  FIG. 14 . Note that it is assumed that the various components provided from the data providing server  10  previously accumulate in the accumulation unit  303  of the distribution server  30 . 
     In step S 301 , the control unit  301  constantly monitors the communication unit  304  to determine whether the reception device  40  requests a component via the network  90 . The request of a component from the reception device  40  is waited in step S 301  and the process goes to step S 302 . 
     In step S 302 , the control unit  301  reads the component requested by the reception device  40  from the accumulation unit  303 . 
     In step S 303 , the control unit  301  controls the communication unit  304  to distribute the component (stream) read from the accumulation unit  303  via the network  90  to the reception device  40 . When the process in step S 303  is completed, the distribution process in  FIG. 14  is completed. 
     The distribution process has been described above. In the distribution process, the various components (streams) provided from the data providing server  10  are distributed via the network  90  in response to the request from the reception device  40 . 
     Reception Process 
     The reception process that the reception device  40  in  FIG. 9  performs will be described with reference to the flowchart in  FIG. 15 . The reception process is performed, for example, when the user starts the reception device  40  by operating a remote controller and instructs channel selection. 
     In step S 401 , the tuner  402  receives broadcast signals via the antenna  401  to extract the broadcast signal on the channel of the selected service from the received broadcast signals and demodulate the extracted signal. The Demux  403  separates the transport stream from the tuner  402  into the components and the control signal. 
     In step S 402 , the control unit  407  selects the optimal component from the component candidates in accordance with the control signal (the signaling information in  FIG. 2 ) from the Demux  403 . 
     Specifically, the control unit  407  obtains the signaling information in  FIG. 2  as the control signal, and thus first recognizes the number of components to be selected based on the “topAttribute” attribute among the candidates. Then, the control unit  407  controls the operation in accordance with the selection determination. 
     For example, when the user selects the components, the control unit  407  displays the information designated as the attribute of the components to be statically selected for each selective component group on the selective layer that is the highest layer with a GUI screen so that the user selects the selective component group (the components). For example, when the receiver automatically selects the components, the control unit  407  selects the selective component group (the components) in accordance with the information designated as the attribute of the components to be statically selected for each selective component group on the selective layer that is the highest layer. 
     The component selection process is basically performed per category such as the video component category, or the audio component category. However, when a view tag is designated as the attribute of the components to be statically selected, the selective component group (the components) is selected across the categories. 
     Next, when there is a plurality of “CompositeComponentGroup” elements in the selected selective component group (the components), the control unit  407  selects the components, which are to be synthesized in accordance with the designated attribute in the composite layer, from the components to be adaptively selected in the adaptive layer that is the lower layer of the composite layer. The control unit  407  controls the selection and synthesis units  404  to  406  to synthesize the components adaptively selected in the synthesis process. 
     When, for example, the “scalable” is designated as the attribute of the components to be synthesized for the composite component group in this example, a base stream transmitted via broadcast and an extended stream transmitted via communication are synthesized. For example, when the “3D” is designated as the attribute for the composite component group, a right-eye image transmitted via broadcast and a left-eye image transmitted via communication are synthesized. 
     The example in which there is a plurality of “CompositeComponentGroup” elements has been described. Note that, however, when there is only a “CompositeComponentGroup” element, the optimal component is adaptively selected from the components to be adaptively selected in the lower adaptive layer in the composite layer as necessary. Alternatively, when there is only a component to be adaptively selected in the adaptive layer, the component is constantly selected. 
     When the optimal component is selected in the process in step S 402 , the process goes to step S 403 . In step S 403 , the video output unit  413  displays the image corresponding to the video and caption components selected in the process in step S 402  on the display. In step S 403 , the audio output unit  415  outputs the voice corresponding to the audio components selected in the process in step S 402  from the loudspeaker. When the process in step S 403  is completed, the reception process in  FIG. 15  is completed. 
     The reception process has been described above. In reception process, the optimal component is selected from a plurality of component candidates that can be received via broadcast or communication in accordance with the control signal (the signaling information in  FIG. 2 ) and presented. This enables the user to watch and listen to the image and voice corresponding to the optimal component selected from the component candidates that can be received, for example, when the user selects the channel of a desired television program. 
     4. Specific Example of Operation 
     A specific example of the operation that the broadcast communication system  1  using the present invention can implement will be described next. 
     (1) Multi-View Display Service 
     In the broadcast communication system  1 , the transmission device  10  transmits a broadcast component and the distribution server  30  distributes a communication component. Thus, the reception device  40  displays a first image via broadcast on the main view, and displays a second image via communication on the sub-view. This enables a multi-screen display or a full-screen display of a selected image. 
     (2) Multilingual Voice and Caption Service 
     The distribution server  30  distributes a foreign language, such as Spanish, voice or caption (audio or caption component) via the network  90  for a television program via broadcast (video and audio components) transmitted from the transmission device  10 . This enables the reception device  40  to output the foreign language voice or superimpose and display the foreign language caption in synchronization with the image of the television program. 
     (3) Sign Language Image Distribution Service 
     The distribution server  30  distributes a sign language image (video component) via the network  90  for a television program via broadcast (video and audio components) transmitted from the transmission device  10 . This enables the reception device  40  to display the sign language image on a sub-screen on the image of the television program. 
     (4) Broadcast and Communication Switch Service 
     While the user watches a television program via broadcast (video and audio components) transmitted from the transmission device  10  on the reception device  40 , the distribution server  30  distributes a program (video and audio components) related to the television program via the network  90  in response to the user&#39;s selection operation. This enables the user to watch the related program on the reception device  40 . Note that a plurality of communication components is prepared and one of the communication components is adaptively selected depending, for example, on the congestion of the communication channel. This selection implements adaptive streaming distribution. When the related program via communication ends, the display is returned to the television program via broadcast. 
     (5) CM Insertion Service 
     When a television program via broadcast (video and audio components) transmitted from the transmission device  10  is switched to a commercial message (CM) while the user watches the broadcast television program on the reception device  40 , a CM (video and audio components) in accordance with the information about the user&#39;s taste is provided from the distribution server  30  via the network  90 . This enables the user to watch a CM specialized for the user (Personalized CM). When the CM specialized for the user via communication ends, the display is returned to the television program via broadcast. 
     (6) Ultra High Definition Television (UHDTV) Compatible Service by Hybrid Distribution 
     For example, in order to provide an image at 4K resolution, it is assumed that the transmission device  10  transmits via broadcast an encoded signal of an image at 2K resolution (video component) as a base stream and the distribution server  30  distributes an encoded image signal (video component) corresponding to the difference between the image at 4K resolution and the image at 2K resolution as an extended stream via the network  90 . When the reception device  40  is compatible with 4K resolution in this example, the reception device  40  can synthesize the base stream transmitted via broadcast and the extended stream transmitted via communication and display the image at 4K resolution. Note that, when the reception device  40  is not compatible with 4K resolution, the reception device  40  displays the image at 2K resolution using only the base stream transmitted via broadcast. 
     Similarly, in order to provide an image at 8K resolution, an encoded signal of an image at 4K resolution (video component) is transmitted as the base stream transmitted via broadcast and an encoded image signal (video component) corresponding to the difference between the image at 8K resolution and the image at 4K resolution is transmitted as the extended stream transmitted via communication. This enables the reception device  40  compatible with 8K resolution to synthesize the streams and display the image at 8K resolution. On the other hand, when the reception device  40  is not compatible with 8K resolution, the reception device  40  displays the image at 4K resolution using only the base stream transmitted via broadcast. 
     In order to provide an image at frame rate of 120 p, an encoded signal of a 60 p image (video component) is transmitted as the base stream transmitted via broadcast and an encoded image signal (video component) corresponding to the difference between the 120 p, image and the 60 p, image is transmitted as the extended stream transmitted via communication. This enables the reception device  40  compatible with the frame rate of 120 p, to synthesize the streams and display the image at the frame rate of 120 p. On the other hand, when the reception device  40  is not compatible with the frame rate of 120 p, the reception device  40  displays the image at the frame rate of 60 p, using only the base stream transmitted via broadcast. 
     (7) Voice Combination Service 
     A language variation voice, a main or explanatory voice, and another content variation voice (audio components) are transmitted from the transmission device  10  or are distributed from the distribution server  30  via the network  90  for a television program via broadcast (video and audio components) transmitted from the transmission device  10 . This enables the reception device  40  to mix and provide the voices in response to the user&#39;s selection operation. 
     (8) Adaptive Streaming Distribution Service Across Broadcast and Communication 
     In the broadcast communication system  1 , the transmission device  10  transmits a component or a plurality of components, and the distribution server  30  distributes a component or a plurality of components via the network  90 . The reception device  40  adaptively selects one of the broadcast and communication components and can provide an image with a quality as high as possible. For example, the transmission device  10  transmits an image at 2K resolution (video component) while the distribution server  30  distributes an image at 4K resolution (video component) via the network  90 . This enables the reception device  40  to implement the adaptive streaming distribution across broadcast and communication, for example, by basically displaying the image at 4K resolution via communication and displaying the image at 2K resolution via broadcast that the reception device  40  can stably receive depending on the congestion of the network  90 . 
     5. Computer Configuration 
     The sequence of processes described above can be performed with hardware or software. When the sequence of processes is performed with software, the program of the software is installed on a computer. The computer is, for example, a computer embedded in dedicated hardware, or a general-purpose computer capable of executing various functions by installing various programs. 
       FIG. 16  is a block diagram of an exemplary configuration of the computer hardware that performs the sequence of processes with the programs. 
     In a computer  900 , a Central Processing Unit (CPU)  901 , a Read Only Memory (ROM)  902 , and a Random Access Memory (RAM)  903  are connected to each other via a bus  904 . Additionally, an input and output interface  905  is connected to the bus  904 . An input unit  906 , an output unit  907 , a recording unit  908 , a communication unit  909 , and a drive  910  are connected to the input and output interface  905 . 
     The input unit  906  includes, for example, a keyboard, a mouse, and a microphone. The output unit  907  includes, for example, a display, and a loudspeaker. The recording unit  908  includes, for example, a hard disk or a non-volatile memory. The communication unit  909  includes, for example, a network interface. The drive  910  drives a removable medium  911  such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory. 
     The computer  900  having the configuration described above performs the sequence of processes, for example, by causing the CPU  901  to load the program stored in the recording unit  908  onto the RAM  903  via the input and output interface  905  and the bus  904  and execute the loaded program. 
     The program that the computer  900  (CPU  901 ) executes can be provided after being recorded in the removable medium  911 , for example, as a package medium. Alternatively, the program can be provided via a wired or wireless communication medium such as a Local Area Network, the Internet, or digital satellite broadcast. 
     The computer  900  can install the program via the input and output interface  905  onto the recording unit  908  by attaching the removable medium  911  to the drive  910 . The program can be received with the communication unit  909  via a wired or wireless communication medium and installed onto the recording unit  908 . Alternatively, the program can previously be installed on the ROM  902  or the recording unit  908 . 
     Note that the program that the computer  900  executes can be a program that chronologically performs the processes in the order described herein, or a program that performs the processes in parallel, or at a time when the execution is necessary, for example, when the program is invoked. 
     Each process step that describes the program that causes the computer  900  to perform each process is not necessarily executed chronologically in the order illustrated as the flowchart, and the processes include processes performed in parallel or individually (for example, parallel processing or processing by the object) herein. 
     The program can be executed by a computer, or by a plurality of computers in decentralized processing. Alternatively, the program can also be executed after being transferred to a remote computer. 
     The system is a collection of a plurality of components (for example, devices, or modules (parts)) herein. It does not matter if all of the components are housed in a housing. Thus, each of the devices housed in different housings and connected via a network, and an apparatus in which the modules are housed in a housing is a system. 
     Note that the embodiments of the present invention are not limited to the embodiments described above, and can variously be changed without departing from the gist of the present invention. For example, the present invention can be the configuration in the cloud computing in which a function can be shared by a plurality of devices and performed by the cooperation of the devices via a network. 
     Each step described in the flowcharts can be performed by a device or shared and performed by a plurality of devices. When a step includes a plurality of processes, the processes in the step can be performed by a device or shared and performed by a plurality of devices. 
     Note that the present invention can have the following configuration. 
     (1) A reception device including: 
     a first reception unit that receives a component transmitted on a broadcast wave; 
     a second reception unit that receives a component distributed via a network; and 
     a control unit that controls operation of each unit, 
     wherein the control unit selects an optimal component from a plurality of components that the reception device is able to receive. 
     REFERENCE SIGNS LIST 
     
         
           1  Broadcast communication system 
           10  Data providing server 
           20  Transmission device 
           30  Distribution server 
           40  Reception device 
           201  Component obtaining unit 
           202  Control signal obtaining unit 
           203  Mux 
           204  Transmission unit 
           301  Control unit 
           302  Component obtaining unit 
           303  Accumulation unit 
           304  Communication unit 
           402  Tuner 
           403  Demux 
           404 ,  405 ,  406  Selection and synthesis unit 
           407  Control unit 
           408  NVRAM 
           409  Input unit 
           410  Communication unit 
           411  Demux 
           412  Video decoder 
           413  Video output unit 
           414  Audio decoder 
           415  Audio output unit 
           416  Caption decoder 
           421  Reception buffer 
           90  Network 
           900  Computer 
           901  CPU