Abstract:
To promptly receive stream data of high definition and a high frame rate, a receiving apparatus receives via a network a digest stream including digest data showing digests of a plurality of main video images and position information showing a position on the network of connection information for receiving the plurality of main video images, receives the connection information via the network on the basis of the position information in the received digest stream, and receives main video data in accordance with the connection information.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to a receiving apparatus and a receiving method and, more particularly, to a technique for receiving stream data via a network.  
         [0003]     2. Related Background Art  
         [0004]     In recent years, Internet broadcast and reproduction have been widespread in association with the improvement of a compressing technique of video/audio data and the spread of a communication environment and an Internet environment which enable high-speed data transfer to be realized. In the Internet broadcast, mainly a downloading type broadcast and a streaming broadcast exist.  
         [0005]     In the downloading type broadcast, it is necessary to download all contents onto a receiver side and, thereafter, reproduce them. If the contents is the contents of a long time, a file size becomes extremely large and a time that is required for downloading increases, so that storing means of a large capacity for storing the contents data to be downloaded is necessary.  
         [0006]     In the streaming broadcast, data can be reproduced while it is received. Since reproduction becomes possible first by buffering the contents as much a few seconds as measured by time, the data can be reproduced in a time shorter than the downloading time of the contents in the downloading type broadcast. Since the data can be abandoned when its reproduction has been finished, it is sufficient that the capacity of the storing means which should be prepared on the receiver side and is used for storing the contents data can be small.  
         [0007]     However, even in the Internet broadcast, there is a tendency such that resolution of the contents, a frame frequency, and the like rise in order to realize a good video image of a large display screen and high definition.  
         [0008]     Also in the streaming broadcast, there is a problem such that it is necessary to buffer the contents of a few seconds at the beginning of monitoring and it takes a long time until the reproduction in association with the increase in resolution of the contents and frame frequency.  
         [0009]     According to JP-A-2001-54090, a technique for easily searching contents, a technique for reproducing the contents by the simple operation, and a technique for enabling the contents to be monitored in a short time have been proposed with respect to the streaming broadcast.  
         [0010]     However, only low-bit rate contents can be monitored in a short time and there is no effect on the streaming contents of high resolution and a high frame frequency.  
       SUMMARY OF THE INVENTION  
       [0011]     It is an object of the invention to provide a receiving apparatus and a receiving method in which the operation for monitoring streaming contents of high quality can be easily and conveniently executed.  
         [0012]     Another object of the invention is to provide a receiving apparatus and a receiving method in which stream data of high definition and a high frame rate can be rapidly received.  
         [0013]     According to one aspect of the invention, there is provided a receiving method of receiving stream data including main video data via a network, comprising the steps of:  
         [0014]     receiving via the network a digest stream including digest data showing a digest of each of the plurality of main video data and position information showing a position on the network where connection information for connecting to at least one of the plurality of main video data exists;  
         [0015]     outputting a video signal regarding the received digest data in order to display it; and  
         [0016]     controlling communicating means so as to receive the connection information via the network on the basis of the received connection information and receive the main video data in accordance with the connection information.  
         [0017]     According to another aspect of the invention, there is provided a receiving apparatus for receiving stream data including main video data via a network, comprising:  
         [0018]     communicating means for receiving via the network a digest stream including digest data showing a digest of each of the plurality of main video data and position information showing a position on the network where connection information for connecting to the plurality of main video data;  
         [0019]     outputting means for outputting a video signal regarding the digest data in the digest stream received by the communicating means to a display apparatus;  
         [0020]     system control means for controlling the communicating means so as to receive the connection information via the network on the basis of the position information in the digest stream received by the communicating means and receive the main video data in accordance with the connection information; and  
         [0021]     storing means for storing the received main video data by a predetermined amount.  
         [0022]     The system control means can further control display control means so that the main video data stored in the storing means is outputted to the display apparatus in response to a display instruction of a main video image by instructing means in place of the video signal regarding the digest stream.  
         [0023]     The system control means can control the communicating means and the storing means so that only the main video data corresponding to the digest data regarding a video image which is being displayed by the display apparatus is received and stored into the storing means.  
         [0024]     Further, the system control means can control the communicating means and the storing means so that the main video data which is received by the communicating means is changed in accordance with a change in position information in the digest stream and the main video data which is newly received after the change is stored into the storing means.  
         [0025]     Or, the system control means can control the communicating means and the storing means so that a plurality of main video data corresponding to the digest data regarding a video image which is being displayed by the display apparatus and a plurality of digest data subsequent to the digest data is received and stored into the storing means.  
         [0026]     The system control means can further control the display control means so that the main video data corresponding to the video signal outputted to the display apparatus among the plurality of main video data stored in the storing means is outputted to the display apparatus in place of the video signal regarding the digest stream in response to a reproducing instruction of the main video image by reproduction instructing means.  
         [0027]     The system control means can control the display control means so that if the instruction is made by the reproduction instructing means while the main video data is outputted to the display apparatus, a predetermined one of the plurality of main video data stored in the storing means is read out and outputted in place of the video data which is being displayed.  
         [0028]     The system control means can control the communicating means and the storing means so that the main video data which is received by the communicating means is changed in accordance with the instruction made by the reproduction instructing means and the newly received main video data is stored in place of the main video data of one of the video data other than the predetermined main video data among the plurality of main video data stored in the storing means.  
         [0029]     The system control means can control the storing means so that when an instruction is made by reservation instructing means, the newly received main video data is stored in place of the video data other than the video data instructed by the reservation instructing means among the plurality of main video data stored in the storing means.  
         [0030]     The system control means can control the communicating means and the storing means so that the plurality of main video data is received and stored in order according to priorities of the plurality of main video data.  
         [0031]     The priorities can correspond to reproducing order in the digest stream.  
         [0032]     The system control means can the control display control means so that predetermined information is displayed by the display apparatus in accordance with an amount of main video data stored in the storing means.  
         [0033]     The position information includes a URL of the connection information. The connection information can be described in a markup language such as HTML or XML.  
         [0034]     The invention includes a program distribution server and a program distributing method for transmitting the digest stream to the foregoing receiving apparatus via the network.  
         [0035]     Or, the invention includes a program distribution server and a program distributing method for distributing the connection information and the main video data to the foregoing receiving apparatus via the network.  
         [0036]     The invention includes a distribution system comprising the receiving apparatus and the program distribution server. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0037]      FIG. 1  is a constructional diagram of a streaming program distribution system to which the invention is applied;  
         [0038]      FIG. 2  is a schematic diagram of a URL table;  
         [0039]      FIGS. 3A and 3B  are diagrams showing an example of contents of the URL table;  
         [0040]      FIG. 4  is a diagram showing a state upon monitoring of a digest program;  
         [0041]      FIG. 5  is a diagram showing a format of a UDP packet;  
         [0042]      FIG. 6  is a diagram showing an example of contents of the UDP packet;  
         [0043]      FIG. 7  is a diagram showing an example of contents of the UDP packet;  
         [0044]      FIG. 8  is a diagram showing an example of contents of the UDP packet;  
         [0045]      FIG. 9  is a diagram showing a state upon monitoring of a current program;  
         [0046]      FIG. 10  is a time-dependent transition diagram of display contents of a display unit  3100  and contents of data which is transferred from an FIFO  3050  to an FIFO  3051 ;  
         [0047]      FIG. 11  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to the FIFO  3051 ;  
         [0048]      FIG. 12  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to the FIFO  3051 ;  
         [0049]      FIG. 13  is a diagram showing a state upon monitoring of the current program;  
         [0050]      FIG. 14  is a constructional diagram of a streaming program distribution system in the second embodiment;  
         [0051]      FIG. 15  is a diagram showing a format of a UDP packet in the second embodiment;  
         [0052]      FIG. 16  is a diagram showing an example of contents of the UDP packet;  
         [0053]      FIG. 17  is a diagram showing an example of contents of the UDP packet;  
         [0054]      FIG. 18  is a diagram showing an example of contents of the UDP packet;  
         [0055]      FIG. 19  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to an FIFO  3053 ;  
         [0056]      FIG. 20  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to the FIFO  3053 ;  
         [0057]      FIG. 21  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to the FIFO  3053 ;  
         [0058]      FIG. 22  is a diagram showing a state after the operation of a reservation button;  
         [0059]      FIG. 23  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to the FIFO  3053 ;  
         [0060]      FIG. 24  is a diagram showing a state after the operation of the reservation button;  
         [0061]      FIG. 25  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to the FIFO  3053 ;  
         [0062]      FIG. 26  is a constructional diagram of the streaming program distribution system to which the invention is applied;  
         [0063]      FIG. 27  is a schematic diagram of a URL table;  
         [0064]      FIG. 28  is a diagram showing an example of contents of the UDP table;  
         [0065]      FIG. 29  is a processing flow for a buffering processing; and  
         [0066]      FIG. 30  is a time-dependent transition diagram of display contents of the display unit  3100  and contents of data which is transferred from the FIFO  3050  to the FIFO  3053 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [heading-0067]     (First Embodiment)  
         [0068]     A streaming program distribution system according to the first embodiment to which the invention is applied will be described hereinbelow with reference to the drawings.  FIG. 1  is a diagram showing a construction of a main section of the streaming program distribution system in the first embodiment.  
         [0069]     In  FIG. 1 , reference numeral  1000  denotes an Internet for transmitting streaming program data, program information, and the like. Reference numeral  2000  denotes a program distribution server for executing accumulation, storage, transmission, and the like of streaming program contents, program information, and the like. The program distribution server  2000  comprises: a streaming distribution server  2100  for distributing a streaming program to a streaming program receiver; and a WEB server  2500  for distributing the program information to the streaming program receiver.  
         [0070]     The streaming program data constructed by a video image and an audio sound has been stored in the streaming distribution server  2100 . Ten streaming program data of programs  1  to  10  has been stored here At the same time, a document (HTML document, here) described in ten markup languages which correspond to the programs  1  to  10  and include connection information to each program has been stored. Peculiar URLs have been allocated to each streaming program data and HTML document. The streaming distribution server  2100  can be accessed from the WEB server  2500  or the outside via the Internet  1000 .  
         [0071]     Digest program contents  2600  comprising digest scenes of the programs stored in the streaming distribution server  2100  has been stored in the WEB server  2500 . The WEB server  2500  also has a URL table  2610  in which a start position and an end position of each program digest in the digest program contents  2600  and the URL of HTML document data including connection information indicative of the connection to each streaming program are made to correspond to each other. Each HTML document is described so as to receive and display each of the corresponding streaming programs as streaming data. A schematic diagram of the URL table is shown in  FIG. 2 .  
         [0072]     For example, the URLs of the HTML document including the connection information to each program are as follows.  
                                                   //host/prog1.htm           //host/prog2.htm           //host/prog3.htm             .             .           //host/prog10.htm                      
 
         [0073]     If the program digest scene of each of the programs  1  to  10  in the digest program contents  2600  has a data capacity of 10 Mbits ( FIG. 3A ), the URL table  2610  is as shown in  FIG. 3B .  
         [0074]     A portal display screen of the WEB server  2500  itself is held in the HTML document. The HTML document is described so that the digest program contents  2600  is received and displayed as streaming data. A transferring protocol in this instance is described as a UDP (User Datagram Protocol) and the number of a port which is used is described as  200 .  
         [0075]     Reference numeral  3000  denotes a streaming program receiver for requesting streaming program data, program information, etc. of the program distribution server  2000 , receiving them from the program distribution server  2000 , and displaying them onto the display unit  3100 . Reference numeral  3010  denotes a communication unit for transmitting and receiving data to/from the Internet  1000 . When the communication unit  3010  receives the program information data from the Internet  1000 , it transfers the program information data to a unit  3020  for obtaining the program information. When the communication unit  3010  receives the streaming data, it transfers the streaming data to a unit  3030  for analyzing a streaming header. Reference numeral  3020  denotes the program information obtaining unit which is constructed in a manner similar to an Internet browser in a personal computer. The program information obtaining unit  3020  requests the HTML document having the program information from the program distribution server  2000 , receives the HTML document from the program distribution server  2000 , analyzes it, and displays it onto the display unit  3100 . The streaming header analyzing unit  3030  analyzes the header in the streaming data and notifies a CPU  3110  of a result of the analysis.  
         [0076]     Reference numerals  3050  and  3051  denote FIFOs serving as buffers for buffering the streaming program data necessary for reproduction of the streaming program. Reference numeral  3060  denotes a decoder for reading out the streaming program data from the FIFOs, decoding the video image and audio sound, outputting the decoded video image, and outputting the decoded audio sound from an audio output unit (not shown). Reference numeral  3090  denotes an OSD controller for superimposing characters, a figure, or the like instructed by the CPU  3110  onto the output video image from the decoder  3060  and displaying a resultant video image onto the display unit  3100 .  
         [0077]     Reference numeral  3070  denotes a unit for receiving a remote control signal. The remote control signal receiving unit  3070  receives and decodes infrared rays transmitted from a remote controller (not shown) and outputs a code of a button of the remote controller operated by the user. Reference numeral  3110  denotes the CPU serving as a controller. The CPU  3110  is constructed so that the button of the remote controller operated by the user can be discriminated via the remote control signal receiving unit  3070  and further integratedly controls each component element. The CPU  3110  has a memory. The CPU  3110  operates in accordance with a program stored in the memory and controls each of the component elements.  
         [0078]     In the above construction, the operation of the streaming program distribution system in the embodiment will be described hereinbelow.  
         [0079]     First, the streaming program receiver  3000  requests the HTML document on the portal display screen from the program distribution server  2000  via the Internet  1000 . The program distribution server  2000  which received the request transmits the relevant HTML document to the streaming program receiver  3000 . The program information obtaining unit  3020  which received the HTML document analyzes the HTML document and displays its contents onto the display unit  3100 .  
         [0080]     Since the HTML document has the description showing that the digest program contents  2600  is received and displayed as streaming data as mentioned above, the digest program contents  2600  is received and displayed onto the display unit  3100 .  
         [0081]     The operation which is executed until the display of the digest program contents  2600  will be described hereinbelow.  
         [0082]     First, the streaming program receiver  3000  obtains the URL, protocol (UDP here as mentioned above), port number ( 200  here as mentioned above), and the like of the digest program contents  2600  from the HTML document, requests the WEB server  2500  to establish a connection on the basis of those information, and establishes a connection for the digest program contents  2600  between the streaming program receiver  3000  and the WEB server  2500 . The streaming program receiver  3000  requests the WEB server  2500  to transmit the digest program contents  2600 , so that the digest program contents  2600  is transmitted from the WEB server  2500  to the streaming program receiver  3000 .  
         [0083]     In the streaming program receiver  3000 , the received digest program contents  2600  is buffered into the FIFO  3050  via the streaming header analyzing unit  3030  and, thereafter, it is decoded by the decoder  3060  and displayed onto the display unit  3100 . Display contents on the display unit  3100  at this time are shown in  FIG. 4 . In the diagram, reference numeral  4000  denotes a background instructed by the HTML document of the portal display screen. Reference numeral  4010  denotes a reproduction display screen of the digest program contents  2600 . While the digest program contents  2600  is reproduced, the streaming program receiver  3000  requests the WEB server  2500  to execute continuation of the transmission, interruption, or the like of the digest program contents  2600  in accordance with an amount of data in the FIFO  3050 .  
         [0084]     Subsequently, the characteristic operation in the embodiment will be described hereinbelow.  
         [0085]     First, in the WEB server  2500 , when the digest program contents  2600  is transmitted to the streaming program receiver  3000 , the URL of the HTML document data including the connection information corresponding to the position of the transmission data is transmitted together with the transmission data. In this instance, the URL is transmitted just after the UDP header and, subsequently, the data of the digest program contents  2600  is transmitted. A data format in this instance is shown in  FIG. 5 . In  FIG. 5 , it is assumed that an area of the connection information URL is fixed to 256 bytes.  
         [0086]     For example, in the case of transmitting the data of 1 kbits from the start of the digest program contents  2600 , the URL of the HTML document data corresponding to the transmission data position is identified as “//host/prog 1 .htm” from the URL table  2610  and data shown in  FIG. 6  is transmitted. In the case of transmitting the subsequent data, that is, the data of 1 kbits from the 1-kbits position of the digest program contents  2600 , the URL of the HTML document data corresponding to the transmission data position is identified as “//host/prog 1 .htm” from the URL table  2610  in a manner similar to that mentioned above and data shown in  FIG. 7  is transmitted. In the case of transmitting the data of 1 kbits from the 20-Mbits position of the digest program contents  2600 , the URL of the HTML document data corresponding to the transmission data position is identified as “//host/prog 3 .htm” from the URL table  2610  and data shown in  FIG. 8  is transmitted.  
         [0087]     In the streaming program receiver  3000 , first, the connection information URL in the received digest program contents  2600  is analyzed in the streaming header analyzing unit  3030 . For example, in the case of receiving the data of 1 kbits from the start of the digest program contents  2600 , the data shown in  FIG. 6  is received and the connection information URL is identified as “//host/prog 1 .htm”.  
         [0088]     Since the connection information URL has changed (from a state where the connection information URL is not received to a state where it is received), the streaming program receiver  3000  requests the HTML document of “//host/prog 1 .htm” on the basis of the URL. This request is made by the URL to the streaming distribution server  2100 . The streaming distribution server  2100  transmits the HTML document of “//host/prog 1 .htm” to the streaming program receiver  3000  on the basis of the request. Since the HTML document has the description showing that the program  1  is received and displayed as streaming data as mentioned above, the program information obtaining unit  3020  which received the HTML document starts to receive the program  1 .  
         [0089]     Although the receiving operation here is similar to the operation upon reception of the digest program contents  2600  mentioned above, the data is not reproduced and displayed. The data of the program  1  which is received is buffered into the FIFO  3051 . Since the reproduction and display are not executed, the streaming program receiver  3000  requests the program distribution server  2000  to execute the interruption or the like of the data in accordance with the amount of data in the FIFO  3051 , thereby performing the operation to prevent a loss of data.  
         [0090]     The streaming program receiver  3000  is constructed in a manner such that the header of the streaming data which is the UDP and is connected to the port  200  is analyzed by the streaming header analyzing unit  3030 . Therefore, the header of the streaming data of the program  1  is not analyzed.  
         [0091]     Subsequently, when the streaming program receiver  3000  receives the subsequent data, that is, the data (the data shown in  FIG. 7 ) of 1 kbits from the 1-kbits position of the digest program contents  2600 , the connection information URL is again identified as “//host/prog 1 .htm” in the streaming header analyzing unit  3030 . In this case, the streaming program receiver  3000  does not execute the special operation such as connection establishment or the like as mentioned above.  
         [0092]     After that, when the data of 1 kbits from the 10-Mbits position of the digest program contents  2600  is received, the connection information URL is identified as “//host/prog 2 .htm” in the streaming header analyzing unit  3030 . In this case, since the connection information URL has changed, the streaming program receiver  3000  stops the data reception of the program  1 , disconnects the connection, and requests the HTML document of “//host/prog 2 .htm” on the basis of the URL. After that, the streaming program receiver  3000  operates in a manner similar to the foregoing processing and starts to receive the program  2 . At this time, the data of the program  1  buffered in the FIFO  3051  is abandoned and the data of the program  2  which is newly received is buffered in the FIFO  3051 .  
         [0093]     While the data of the program  1  buffered during the above operation is abandoned and an amount of data of the program  2  which is newly received in the FIFO  3051  reaches a capacity of the data which can be reproduced, a message showing such a fact is displayed via the OSD controller  3090 . Contents displayed on the display unit  3160  at this time are shown at  9000  in  FIG. 9 .  
         [0094]     Similarly, when the data (shown in  FIG. 8 ) of 1 kbits from the 20-Mbits position of the digest program contents  2600  is received, the connection information URL is identified as “//host/prog 3 .htm” in the streaming header analyzing unit  3030  and the data of the program  2  is buffered into the FIFO  3051 .  
         [0095]     A time-dependent transition diagram of the display contents on the display unit  3100  and the contents of data which is transferred to the FIFOs  3050  and  3051  in the above operation is shown in  FIG. 10 .  
         [0096]     In  FIG. 10 , the operation which is executed when the user operates a monitoring button on the remote controller at a point of time “a” will be described hereinbelow. It corresponds to the case where while the user monitors the digest scene of the program  1  of the digest program contents  2600  on the portal display screen, he likes the monitoring program, that is, the program  1  and shifts the monitoring target to the current program.  
         [0097]     The CPU  3110  which detected the operation of the monitoring button controls the decoder  3060  so as to read out the streaming data from the FIFO  3051  because the data in the FIFO  3051  is in a reproducible state, and switches the display contents on the display unit  3100  to the reproduction display screen of the program  1 . At the same time, the reception of the digest program contents  2600  is stopped and the connection is disconnected.  
         [0098]     After that, since the reception of the digest program contents  2600  is stopped, the change in connection information URL is not detected in the streaming header analyzing unit  3030  but the reception of the data of the program  1  is continued and the reproduction display screen of the program  1  is continuously displayed on the display unit  3100 .  
         [0099]     A time-dependent transition diagram of the display contents on the display unit  3100  and the contents of data which is transferred to the FIFOs  3050  and  3051  in this case is shown in  FIG. 11 .  
         [0100]     As mentioned above, while the digest program is monitored, the user can soon start to monitor the current program without a waiting time for buffering or the like by the simple operation such as only the operation of the monitoring button.  
         [0101]     Returning to  FIG. 10 , the operation which is executed when the user operates the monitoring button on the remote controller at a point of time “b” will be described hereinbelow. It corresponds to the case where while the user monitors the digest scene of the program  2  of the digest program contents  2600  on the portal display screen, he likes the monitoring program, that is, the program  2  and shifts the monitoring target to the current program.  
         [0102]     The CPU  3110  which detected the operation of the monitoring button waits until the apparatus enters the reproducible state because the data in the FIFO  3051  is in an unreproducible state. When the data in the FIFO  3051  enters the reproducible state, the CPU  3110  switches the decoder  3060  so as to read out the streaming data from the FIFO  3051  and switches the display contents on the display unit  3100  to the reproduction display screen of the program  2 . At the same time, the reception of the digest program contents  2600  is stopped and the connection is disconnected.  
         [0103]     After that, the reproduction display screen of the program  2  is continuously displayed on the display unit  3100  in a manner similar to that mentioned above.  
         [0104]     A time-dependent transition diagram of the display contents on the display unit  3100  and the contents of data which is transferred to the FIFOs  3050  and  3051  in the above case is shown in  FIG. 12 .  
         [0105]     As mentioned above, the user can monitor the current program by the simple operation such as only the operation of the monitoring button. Since the buffering of the current program is started together with the switching of the contents of the digest program contents  2600 , the waiting time until the start of monitoring is shorter than that in the conventional technique.  
         [0106]     Since the digest program can be monitored for the waiting time until the monitoring of the current program, the user does not feel mental annoyance. Until the data amount reaches the capacity of the data which can be reproduced, a message indicative of such contents is displayed as shown in  FIG. 9 . Therefore, the user can easily distinguish the digest program contents.  2600  from the current program.  
         [0107]      FIG. 13  shows display contents on the display unit  3100  upon monitoring of the current program. In  FIG. 13 , reference numeral  1301  denotes a reproduction display screen of the current program and  1302  indicates a background on which a program title  1303  and an operation description  1304  are displayed. Those backgrounds have been described in the HTML document including the connection information.  
         [0108]     As shown in the operation description  1304 , when the user operates a return button on the remote controller, the streaming program receiver  3000  requests the HTML document on the portal display screen from the program distribution server  2000  via the Internet  1000  and repeats the above operations.  
         [heading-0109]     (Second embodiment)  
         [0110]     A streaming program distribution system according to the second embodiment to which the invention is applied will be described hereinbelow. A construction of a main section of the streaming program distribution system in the second embodiment is similar to that of  FIG. 1  and different portions will be explained hereinbelow.  
         [0111]     The streaming program receiver  3000  in the second embodiment is shown in  FIG. 14 . In the diagram, reference numerals  3050  to  3053  denote FIFOs and these FIFOs are different from the FIFOs in the first embodiment.  
         [0112]     In the construction of  FIG. 14 , the operations which are executed until the streaming program receiver  3000  requests the HTML document on the portal display screen from the program distribution server  2000  and finally displays the digest program contents  2600  onto the display unit  3100  are similar to those in the first embodiment.  
         [0113]     Subsequently, the operation of the WEB server  2500  will be described.  
         [0114]     When the digest program contents  2600  is transmitted to the streaming program receiver  3000 , the WEB server  2500  in the second embodiment transmits the URL of the HTML document data including the connection information corresponding to the position of the transmission data and the URLs of the HTML document data including the connection information corresponding to the next digest program and the next to next digest program together with the transmission data. A data format at this time is shown in  FIG. 17 .  
         [0115]     In  FIG. 15 , it is assumed that each area of the connection information URL is fixed to 128 bytes and order of them has been also predetermined.  
         [0116]     For example, in the case of transmitting the data of 1 kbits from the start of the digest program contents  2600 , the URL of the HTML document data corresponding to the position of the transmission data is identified as “//host/prog 1 .htm” from the URL table  2610 . As URLs of the HTML document data including the connection information corresponding to the next digest program and the next to next digest program, “//host/prog 2 .htm” stored in the position next to preceding URL “//host/prog 1 .htm” and “//host/prog 3 .htm” stored in the position next to “//host/prog 2 .htm” are referred to on the URL table  2610 . Thus, data shown in  FIG. 16  is transmitted.  
         [0117]     In the case of transmitting the subsequent data, that is, the data of 1 kbits from the 1-kbits position of the digest program contents  2600 , the URL of the HTML document data corresponding to the position of the transmission data is identified as “//host/prog 1 .htm” from the URL table  2610  in a manner similar to the above. As URLs of the HTML document data including the connection information corresponding to the next digest program and the next to next digest program, “//host/prog 2 .htm” and “//host/prog 3 .htm” are referred to on the URL table  2610  in a manner similar to the above. Thus, data shown in  FIG. 17  is transmitted.  
         [0118]     In the case of transmitting the data of 1 kbits from the 20-Mbits position of the digest program contents  2600 , the URL of the HTML document data corresponding to the position of the transmission data is identified as “//host/prog 3 .htm” from the URL table  2610 . As URLs of the HTML document data including the connection information corresponding to the next digest program and the next to next digest program, “//host/prog 4 .htm” stored in the position next to preceding URL “//host/prog 3 .htm” and “//host/prog 5 .htm” stored in the position next to “//host/prog 4 .htm” are referred to on the URL table  2610 . Thus, data shown in  FIG. 18  is transmitted.  
         [0119]     In the streaming program receiver  3000 , first, the connection information URL of the received digest program contents  2600  is analyzed in the streaming header analyzing unit  3030 . For example, in the case of receiving the data of 1 kbits from the start of the digest program contents  2600 , the data shown in  FIG. 16  is received and the connection information URLs are identified as follows.  
                                                       Current program digest   “//host/prog1.htm”           Next program digest   “//host/prog2.htm”           Next to next program digest   “//host/prog3.htm”                      
 
         [0120]     Since the connection information URL has changed (from a state where the connection information URL is not received to a state where it is received), the streaming program receiver  3000  requests the HTML document of “//host/prog 1 .htm” in a manner similar to the first embodiment and stores the data of the program  1  into the FIFO  3051 . Further, in the embodiment, the streaming program receiver  3000  also requests the HTML documents of “//host/prog 2 .htm” and “//host/prog 3 .htm”, stores the data of the program  2  into the FIFO  3052 , and stores the data of the program  3  into the FIFO  3053 , respectively.  
         [0121]     Subsequently, when the streaming program receiver  3000  receives the subsequent data, that is, the data (data shown in  FIG. 17 ) of 1 kbits from the 1-kbits position of the digest program contents  2600 , it does not execute the operation such as connection establishment or the like because the change in connection information URL is not detected.  
         [0122]     After that, when the data of 1 kbits from the 10-Mbits position of the digest program contents  2600  is received, the connection information URLs are identified in the streaming header analyzing unit  3030  as follows.  
                                                       Current program digest   “//host/prog2.htm”           Next program digest   “//host/prog3.htm”           Next to next program digest   “//host/prog4.htm”                      
 
         [0123]     In this case, since the connection information URL has changed, the streaming program receiver  3000  stops the reception of the data of the program  1  corresponding to the preceding “current program digest”, disconnects the connection thereof, and requests the HTML document of “//host/prog 4 .htm” which has newly been identified on the basis of the URL.  
         [0124]     Subsequently, the reception of the program  4  is started in a manner similar to the above. At this time, the data in the FIFO  3051  used for buffering of the stopped data reception is abandoned and the data of the program  4  which is newly received is stored into the FIFO  3051 .  
         [0125]     After that, when the data of 1 kbits from the 20-Mbits position of the digest program contents  2600  is received, the connection information URLs are identified in the streaming header analyzing unit  3030  as follows.  
                                                       Current program digest   “//host/prog3.htm”           Next program digest   “//host/prog4.htm”           Next to next program digest   “//host/prog5.htm”                      
 
         [0126]     In this case, since the connection information URL has changed, the streaming program receiver  3000  stops the reception of the data of the program  2  corresponding to the preceding “current program digest”, disconnects the connection thereof, and requests the HTML document of “//host/prog 5 .htm” which has newly been identified on the basis of the URL.  
         [0127]     Subsequently, the reception of the program  5  is started in a manner similar to the above. At this time, the data in the FIFO  3052  used for buffering of the stopped data reception is abandoned and the data of the program  4  which is newly received is stored into the FIFO  3052 .  
         [0128]     A time-dependent transition diagram of the display contents on the display unit  3100  and the contents of data which is transferred to the FIFOs  3050  and  3053  in the above operation is shown in  FIG. 19 .  
         [0129]     In  FIG. 19 , the operation which is executed when the user operates the monitoring button on the remote controller at a point of time “a” will be described hereinbelow. It corresponds to the case where while the user monitors the digest program contents  2600 , he likes the monitoring program  1  and shifts the monitoring target to the current program in a manner similar to the first embodiment.  
         [0130]     The CPU  3110  which detected the operation of the monitoring button controls the decoder  3060  so as to read out the streaming data from the FIFO  3051  because the data in the FIFO  3051  is in a reproducible state, and switches the display contents on the display unit  3100  to the reproduction display screen of the program  1 . At the same time, the reception of the digest program contents  2600  is stopped, the connection is disconnected, and further, the buffering is performed. Also with respect to the programs  2  and  3 , the data reception is stopped and the connection is disconnected.  
         [0131]     After that, since the reception of the digest program contents  2600  is stopped and the change in connection information URL is not detected in the streaming header analyzing unit  3030 , the reception of the data of the program  1  is continued and the reproduction display screen of the program  1  is continuously displayed on the display unit  3100 .  
         [0132]     A time-dependent transition diagram of the display contents on the display unit  3100  and the contents of data which is transferred to the FIFOs  3050  and  3053  in this case is shown in  FIG. 20 .  
         [0133]     As mentioned above, while the digest program is monitored, the user can soon start to monitor the current program without a waiting time for buffering or the like by the simple operation such as only the operation of the monitoring button.  
         [0134]     Returning to  FIG. 19 , the operation which is executed when the user operates the monitoring button on the remote controller at a point of time “b” will be described hereinbelow. It corresponds to the case where while the user monitors the digest program contents  2600 , he likes the monitoring program  2  and shifts the monitoring target to the current program in a manner similar to the first embodiment.  
         [0135]     The CPU  3110  which detected the operation of the monitoring button controls the decoder  3060  so as to read out the streaming data from the FIFO  3052  because the data in the FIFO  3052  is in a reproducible state and switches the display contents on the display unit  3100  to the reproduction display screen of the program  2 . At the same time, the reception of the digest program contents  2600  is stopped, the connection is disconnected, and further, the buffering is performed. Also with respect to the programs  3  and  4 , the data reception is stopped and the connection is disconnected.  
         [0136]     After that, the reproduction display screen of the program  2  is continuously displayed on the display unit  3100 .  
         [0137]     A time-dependent transition diagram of the display contents on the display unit  3100  and the contents of data which is transferred to the FIFOs  3050  and  3053  in the above case is shown in  FIG. 21 .  
         [0138]     As mentioned above, the user can soon monitor the current program without a waiting time for buffering or the like by the simple operation such as only the operation of the monitoring button even if he operates the monitoring button just after the program scene of the digest program changed during the monitoring of the digest program.  
         [0139]     The display contents on the display unit  3100  and the operation which is executed when the user operates the return button upon monitoring of the current program are similar to those in the first embodiment.  
         [heading-0140]     (Third Embodiment)  
         [0141]     Subsequently, the third embodiment will be described.  
         [0142]     A construction of a main section of the streaming program distribution system in the third embodiment is similar to that of the second embodiment and different portions will be explained hereinbelow.  
         [0143]     In the third embodiment, the operations which are executed until the streaming program receiver  3000  requests the HTML document on the portal display screen from the program distribution server  2000  and finally displays the digest program contents  2600  onto the display unit  3100 , the data of the program  1  is buffered into the FIFO  3051 , the data of the program  2  is buffered into the FIFO  3052 , and the data of the program  3  is buffered into the FIFO  3053 , that is, the operations which are executed until a state shown in  FIG. 19  are similar to those in the second embodiment.  
         [0144]     In  FIG. 19 , when the user operates the reservation button on the remote controller at a point of time “a” (corresponds to the case where although he likes the program  1  during the monitoring of the digest program contents  2600 , he does not shift the monitoring target to the current program), the CPU  3110  which detects the operation of the reservation button sets a flag indicative of the reservation into the FIFO  3051  in which the data of the program  1  has been stored.  
         [0145]     In this instance, the CPU  3110  controls the OSD controller  3090  so that the FIFO  3051  in which the flag indicative of the reservation button has been set and a “ 1 ” button on the remote controller are made to correspond to each other and information showing that the buffering of the program  1  has been reserved and information showing the corresponding button on the remote controller, that is, “ 1 ” are displayed on the display unit  3100 . Display contents on the display unit  3100  at this time are shown in  FIG. 22 . Reference numeral  2200  in  FIG. 22  denotes those information.  
         [0146]     After that, when the data of 1 kbits from the 10-Mbits position of the digest program contents  2200  is received, the connection information URLs are identified in the streaming header analyzing unit  3030  as follows.  
                                                       Current program digest   “//host/prog2.htm”           Next program digest   “//host/prog3.htm”           Next to next program digest   “//host/prog4.htm”                      
 
         [0147]     In the embodiment, in this case, since the connection information URL has changed, first, the streaming program receiver  3000  checks the reservation flag of the FIFO  3051  in which the data of the current program digest has already been stored. Since the reservation flag has been set here, the receiver  3000  checks the reservation flag of the FIFO  3053  in which the data of the next to next program digest has already been stored. Since the reservation flag is not set here, the streaming program receiver  3000  stops the data reception of the program  3 , disconnects the connection, and requests the HTML document of “//host/prog 4 .htm” which was newly identified on the basis of the URL. After that, the reception of the program  4  is started. At this time, the data of the program  4  which is newly received is stored into the FIFO  3052  in which the stopped data has been stored. The above time-dependent transition diagram is shown in  FIG. 23 .  
         [0148]     When the user operates the monitoring button on the remote controller at a point of time “b” in the state shown in  FIG. 23 , the user can soon start to monitor the current program of the program  2  without a waiting time for buffering or the like in a manner similar to the second embodiment.  
         [0149]     When the user operates the “ 1 ” button on the remote controller at a point of time “b” in the state shown in  FIG. 23 , it corresponds to the case where he likes the program  1  which has been reserved earlier than the program  2  during the monitoring of the digest program contents  2600  and shifts the monitoring target to the current program of the program  1 .  
         [0150]     The CPU  3110  which detected the operation of the “ 1 ” button controls the decoder  3060  so as to read out the streaming data from the FIFO  3051  because the data in the FIFO  3051  corresponding to the “ 1 ” button is in a reproducible state, and switches the display contents on the display unit  3100  to the reproduction display screen of the program  1 . The reception of the digest program contents  2600  and the data which is being buffered is stopped and the connection is disconnected.  
         [0151]     As mentioned above, the user can soon monitor the current program of the past digest program which has been reserved earlier without a waiting time for buffering or the like only by the button operation on the remote controller during the monitoring of the digest program.  
         [0152]     Returning to  FIG. 19 , when the user operates the reservation button on the remote controller at a point of time “b” (it corresponds to the case where although he likes the program  2  during the monitoring of the digest program contents  2600 , he does not shift the monitoring target to the current program), the CPU  3110  which detects the operation of the reservation button sets the flag indicative of the reservation into the FIFO  3052  in which the data of the program  2  has been stored.  
         [0153]     At this time, the CPU  3110  controls the OSD controller  3090  so that the FIFO  3052  in which the flag indicative of the reservation button has been set and a “ 2 ” button on the remote controller are made to correspond to each other and the information showing that the buffering of the program  1  has been reserved and information showing the corresponding button on the remote controller, that is, “ 2 ” are displayed on the display unit  3100 . Display contents on the display unit  3100  at this time are shown in  FIG. 24 . Reference numeral  2400  in  FIG. 24  denotes those information.  
         [0154]     After that, when the data of 1 kbits from the 20-Mbits position of the digest program contents  2400  is received, the connection information URLs in the streaming header analyzing unit  3030  are identified as follows.  
                                                       Current program digest   “//host/prog3.htm”           Next program digest   “//host/prog4.htm”           Next to next program digest   “//host/prog5.htm”                      
 
         [0155]     In this case, since the connection information URL has changed, first, the streaming program receiver  3000  checks the reservation flag of the FIFO  3052  in which the data of the current program digest has already been stored. Since the reservation flag has been set here, the receiver  3000  checks the reservation flag of the FIFO  3051  in which the data of the next to next program digest has already been stored. Since the reservation flag is not set here, the streaming program receiver  3000  stops the data reception of the program  3 , disconnects the connection, and requests the HTML document of “//host/prog 4 .htm” which was newly identified on the basis of the URL. After that, the reception of the program  4  is started.  
         [0156]     At this time, the data of the program  4  which is newly received is stored into the FIFO  3051  in which the stopped data has been stored. The above time-dependent transition diagram is shown in  FIG. 25 .  
         [0157]     When the user operates the monitoring button on the remote controller at a point of time “c” in the state shown in  FIG. 25 , the user can soon start to monitor the current program of the program  3  without a waiting time for buffering or the like. When the user operates the “ 2 ” button on the remote controller, the user can soon start to monitor the current program of the program  2  without a waiting time for buffering or the like.  
         [heading-0158]     (Other embodiments)  
         [0159]     The streaming distribution server  2100  and the WEB server  2500  in the first to third embodiments can be separated as shown in  FIG. 26 .  
         [0160]     In  FIG. 26 , it is assumed that the streaming program data of the programs  1  to  5  has been stored in a streaming distribution server  2110  and the streaming program data of the programs  6  to  10  has been stored in a streaming distribution server  2120 , respectively. In this case, if the streaming distribution server  2110  is assumed to be “host 2110 ” and the streaming distribution server  2120  is assumed to be “host 2120 ”, the URL table  2610  in the WEB server  2500  is as shown in  FIG. 27 .  
         [0161]     As will be easily presumed from the first and second embodiments, order in the URL table  2610  in the first embodiment can be made different as shown in  FIG. 28 .  
         [0162]     Although the FIFOs and the buttons on the remote controller have been made to correspond to each other together with the operation of the reservation button in the third embodiment, the button numbers can be also preliminarily statically allocated as follows.  
                                                       FIFO 3051   button “1”           FIFO 3052   button “2”           FIFO 3053   button “3”                      
 
         [0163]     In the first to third embodiments, the format of the UDP packet has been constructed in a manner such that the URL of the HTML document data including the connection information is arranged just after the UDP header and the data of the digest program contents  2600  is arranged after the URL. However, the data format of the digest program contents  2600  can be set to a TS (Transport Stream) which is specified by MPEG2 (Moving Picture Experts Group Phase 2) and ISO/IEC13818 and can be also constructed in a manner such that TS data is transmitted in the UDP packet and the URL of the HTML document data including the connection information is included in an adaptation field or the like in a TS packet.  
         [0164]     The buffering from the FIFO  3051  to the FIFO  3053  simultaneously occurs at the initial stage in the second and third embodiments. At this time, it is desirable to allocate priorities to the FIFOs and execute the buffering to them. In this case, the data corresponding to the current program and having a possibility that the current program digest is immediately needed with respect to time is set to the highest priority as follows.  
                                                       High priority   FIFO 3051           Middle priority   FIFO 3052           Low priority   FIFO 3053                      
 
         [0165]     Since the apparatus operates in accordance with a processing flow shown in, for example,  FIG. 29 , the buffering of the FIFO  3051  is preferentially executed. A time-dependent transition diagram of the display contents of the display unit  3100  and the contents of data which is transferred to the FIFO  3050  to the FIFO  3053  at this time is shown in  FIG. 30 . The requesting and interrupting processes of the buffering according to an amount of data in the FIFO  3050  are omitted in the processing flow shown in  FIG. 29 .  
         [0166]     By the above buffering control, the waiting time until the current program is monitored in the case where the user immediately operates the monitoring button after the start of the monitoring of the digest program can be shortened.  
         [0167]     As described above, according to the invention, since the corresponding main video data is received from the network and stored during the monitoring of the digest program, the main video image can be promptly displayed without a waiting time for buffering or the like.