JP4956797B2 - Content transmitting apparatus, receiving apparatus and system - Google Patents

Description

  The present invention relates to a content transmission device, a reception device, and a system. The content transmission device, the reception device, and the content transmission device, the reception device, and the content transmission time can be shortened and the convenience of the user can be improved by enabling broadcast and communication to be received in cooperation. About the system.

As a conventional example of a system that links communication and broadcasting, for example, there is one described in Patent Document 1 below. In this Patent Document 1, multimedia data such as video, audio, music, and high-definition images is received / stored from a broadcasting station, and insufficient information is transmitted to a narrowband ISDN or telephone connected to a bidirectional communication interface. A system such as a STB (Set Top Box) or a PC having a content reconfiguration function that can be downloaded from an information providing server via a line or the Internet and adding the shortage information to the multimedia data to reconfigure the content. It is disclosed.
JP 2001-34523 A

  However, in the above-described conventional system, when data such as video, audio and music is received from a broadcast, the acquisition time of the data or content cannot be shortened. Further, when receiving the data from the broadcast and wishing to acquire the data from the beginning, no consideration has been given so that the data can be acquired from the beginning.

  The present invention has been made in view of the above-described prior art, and an object of the present invention is to link broadcast and communication so as to shorten the acquisition time of broadcast data or content, and to improve the front part even during the broadcast. It is an object of the present invention to provide a content transmission device, a reception device, and a system that can acquire the broadcast data or content.

In order to achieve the above object, the present invention includes a dividing unit that divides transmitted content into data of a predetermined size, a storage unit that temporarily stores the divided data together with its serial number, and the storage Multicast transmission for packetizing the data read from the storage unit and multicasting so that the data numbers attached to the packet are in ascending order Means, unicast transmission means for packetizing the data read from the storage unit and transmitting the data numbers attached to the packets in descending order, and data transmitted by the multicast Connection destination information transmitting means for transmitting connection destination information for receiving the data by unicast, and the control unit receives the content. In case of a request for transmission from the side, the data from the storage unit, the data transmission requested number read so that the descending order sent to the unicast transmission means, the transmission request packet number is the beginning of the Data is read in descending order from the last number of the content. When the number N is other than the top, the data is read in descending order from the data of the number N-1, and when the top is read, the last data is read. When the reception end notification sent from the content receiving side is received, reading in descending order from the storage unit is stopped and transmission from the unicast transmission means is ended. There is a first feature.

The present invention also provides a user I / F that designates download from a list of contents to be multicast, multicast download means for downloading when the designated content is transmitted by multicast, and receiving during multicast download. A multicast packet number obtaining means for obtaining a packet number, a data transmission request means for requesting transmission of the designated content by unicast, and a unicast download means for downloading data transmitted in descending order by the unicast. Unicast packet number acquisition means for acquiring a received packet number during unicast download, and the multicast packet number acquired by the multicast packet number acquisition means and the unicast When the unicast packet number acquired by preparative packet number obtaining means has a continuous or match, and a control unit for the processing of the reception end of the content, the control unit is acquired by the multicast packet number obtaining means A content receiving device that notifies the content transmission side of the end of content transmission when the received multicast packet number and the unicast packet number acquired by the unicast packet number acquisition means are continuous or coincides with each other is provided. There is a second feature.

  A third feature is that a content transmission / reception system including the content transmission device and the content reception device is provided.

  According to the present invention, it is possible to shorten broadcast content acquisition time by linking broadcasting and communication. Also, it becomes possible to acquire the broadcast content of the portion that has passed even during the broadcast. For this reason, it is possible to greatly enhance the convenience of the user for obtaining broadcast contents. In particular, the effect is great when long-term broadcast data such as a few hours or more is acquired.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a transmission side apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a schematic configuration of a reception side apparatus.

  As shown in FIG. 1, the transmission side device is a file storage unit 1 such as a hard disk for storing contents to be transmitted, connection destination information for receiving the contents by unicast (unicast address on the transmission side), and the like. A file compression unit 2 that compresses the content read from the file storage unit 1, a file division unit 3 that divides the file to fit the packet size, and temporarily stores the divided data. The storage unit 4, the interface distribution means 5, the divided data management / control unit 6 for managing the data stored in the storage unit 4 and controlling the storage / reading thereof, and the unicast I on the receiving device side Data acquisition request receiving unit 7 that receives a data acquisition request from / F, and a schedule distribution unit that performs schedule distribution such as reservation distribution And it has a door. The interface delivery means 5 includes a multicast I / F 5a and a unicast I / F 5b. The file compression unit 2 is not necessary when the data from the file storage unit 1 is not compressed.

  On the other hand, as shown in FIG. 2, the receiving-side apparatus has a multicast interface (multicast I / F) 11a, a unicast interface (unicast I / F) 11b, and divided data for storing the received divided data. Storage unit 12, file composition unit 13, file decompression unit 14, file storage unit 15, divided data management / control unit 16, and content acquisition connection destination information extraction unit that extracts connection destination information for content acquisition from received data 17, a user interface (user I / F) 18, and a data acquisition request unit 19. The divided data storage unit 12 includes a multicast data storage unit 12a and a unicast data storage unit 12b. The file decompression unit 14 is not necessary when the received data is not compressed. The multicast I / F 11a and the multicast data storage unit 12a can be called multicast download means, and the unicast I / F 11b and the unicast data storage unit 12b can be called unicast download means.

  Next, an outline of operations of the transmission side device and the reception side device of the present embodiment will be described with reference to FIG. 1 and FIG.

  The transmission side apparatus reads the content file, connection destination information, and the like from the file storage unit 1 in accordance with an instruction from the schedule distribution unit 8 and the like. Sent to 5. The connection destination information p may be transmitted to the interface distribution means 5 via the file compression unit 2 and the file division unit 3. The file compression unit 2 compresses the input file and outputs it to the file division unit 3. Note that uncompressed data may be input to the file dividing unit 3 without being compressed. The compressed data or the uncompressed data is divided by the file dividing unit 3 so as to match the size of the packet and stored in the storage unit 4. For example, it is divided into 1500 bytes per packet and stored.

  FIG. 3 is a conceptual diagram of data stored in the storage unit 4. The divided data D is stored with serial numbers (for example, 1, 2, 3,... 99, 100). The Thereafter, the accumulated data is read out in ascending order and sent to the multicast I / F 5a under the control of the divided data management / control unit 6. The multicast I / F 5a packetizes these data, adds the serial number of the data as a packet number, and transmits it to the multicast I / F 11a on the receiving side according to the connection destination information p (when data is packetized, the data number is also If both are packetized, you can also choose not to add data numbers when packetizing). Note that the connection destination information p or the transmission source information is also multicast from the multicast I / F 5a.

  When the receiving side apparatus receives the multicast broadcast, the user I / F 18 issues a command to receive the multicast broadcast. Then, since the divided data management / control unit 16 issues an instruction to store the multicast data in the multicast data storage unit 12a, the multicast data is stored in the storage unit 12a. During the reception of the multicast broadcast, the multicast I / F 11a notifies the divided data management / control unit 16 of the received packet number, so that the divided data management / control unit 16 monitors and manages the packet number. The packet serial number is checked, and if there is a missing packet, a retransmission is requested via the data transmission request unit 19. The file synthesizing unit 13 synthesizes the packetized data in the order of data numbers, and when the data is compressed, the file decompressing unit 14 converts it into uncompressed data. The uncompressed data, that is, the content is stored in the file storage unit 15. Upon completion of content storage, the file storage unit 15 outputs a transfer completion notification signal r to the divided data management / control unit 16.

  In addition, when data numbers and packet numbers are switched in order due to the application of the error correction function, the minimum unit of one cycle or one group to which the error correction processing is applied can be handled in the same way as the data number. Good.

  The above is the general operation when receiving a multicast broadcast. When the broadcast is unicasted, the user I / F 18 specifies the content to be acquired and the multicast and / or unicast specification. Made. Further, the content acquisition connection destination information extraction unit 17 extracts the content acquisition connection destination information p or the transmission source information that has already been sent from the transmission side device to the divided data storage unit 12.

  When the designation of reception by unicast is included, the smallest packet number of the packet that has received the multicast content is designated, and the content acquisition request (including the content designation) by unicast is the content acquisition destination The data is transmitted via the divided data management / control unit 16, the data transmission request unit 19, and the unicast I / F 11b with (transmission side unicast address) as the destination. As a result, the content acquisition request and the packet number are received by the data acquisition request receiving unit 7 of the transmitting apparatus. The data acquisition request receiving unit 7 notifies the divided data management / control unit 6 of the specification of the received content and the packet number. The divided data management / control unit 6 reads the data from the storage unit 4 in descending order starting from a number smaller than the smallest packet number of the multicast received packet acquired from the receiving device. The sent data is sent to the unicast I / F 5b. The data read from the storage unit 4 in ascending order is continuously read in ascending order and continuously sent to the multicast I / F 5a.

  For example, when there is data 1 to 100 as shown in FIG. 3 and the unicast reception is instructed by the user at the head (= 1) as the multicast address, 1, 2, 2, are assigned to the multicast I / F 5a. The data read out in ascending order is sent to the unicast I / F 5b, and the data read out in descending order from the last data (= 100) to 100, 99, 98,. Sent. As another example, when the multicast broadcast is received from the middle, for example, when the smallest packet number of the multicast received by the receiving device is 10, and the unicast reception is instructed by the user, the multicast I / F 5a The data read out in ascending order is sent continuously, and the data read out in descending order of 9, 8, 7,..., 1,100, 99,. It is done.

  The packetized data sent from the multicast I / F 5a and unicast I / F 5b on the transmission side is received by the multicast I / F 11a and unicast I / F 11b of the reception side device that has made a content acquisition request and is maintained connected. Are stored in the multicast data storage unit 12a and the unicast data storage unit 12b, respectively. At this time, the packet number q of the received data is notified to the divided data management / control unit 16. The divided data management / control unit 16 monitors the number q, and when the received multicast data packet number and the unicast data packet number are consecutive, instructs the divided data storage unit 12 to end the storage. . For example, when the packet number of multicast data sent in ascending order is 50 and the packet number of unicast data sent in descending order is 51, the packet numbers of both data are consecutive, and the divided data storage unit Since all data from No. 1 to No. 100 are accumulated in 12, the accumulation is terminated.

  Note that the packet number of the multicast data and the packet number of the unicast data are not necessarily continuous between a series of content receptions depending on the total number of divided data (M) of the content and the timing of reception via multicast and reception via unicast. It is also assumed that there is a match without. In this case, the divided data management / control unit 16 compares several consecutive packet numbers received via multicast with several consecutive packet numbers received via unicast, and if there is a matching packet number. If so, the accumulation ends.

  Next, the packet serial number is checked, and if there is a missing packet, a retransmission is requested via the data transmission request unit 19 and the unicast I / F 11b.

  The file composition unit 13 reads the data from the multicast data storage unit 12a and the unicast data storage unit 12b, combines the data so that they are continuous, and sends the data to the file decompression unit 14. For example, the numbers 1, 2, 3,... 99, 100 are combined so that the data are continuous and sent to the file decompression unit 14. The file decompression unit 14 converts the compressed data into uncompressed data. The uncompressed data, that is, the content is stored in the file storage unit 15. Upon completion of content storage, the file storage unit 15 outputs a transfer completion notification signal r to the divided data management / control unit 16.

  FIG. 4 is a flowchart showing details of the operation of the transmission-side apparatus described above. In step S1, content (file) to be multicast-transmitted from the file storage unit 1, connection destination information, and the like are read. The read content is sent to the file compression unit 2, and the connection destination information is sent to the multicast transmission unit 5a. The connection destination information p may be transmitted to the interface distribution means 5 via the file compression unit 2 and the file division unit 3. The connection destination information is transmitted to the receiving side via the interface distribution means 5. In step S2, it is determined whether or not the content is to be compressed. If so, the process proceeds to step S3 and is compressed by the file compression unit 2. Next, proceeding to step S4, the compressed data or the uncompressed data is divided by the file dividing unit 3 so as to fit the packet size. For example, it is divided into 1500 bytes per packet. In step S5, the divided data is temporarily stored in the storage unit 4. At this time, the total number of data (M) is acquired. For example, as shown in FIG. 3, if the content is divided into 100 pieces, M = 100. Next, the process proceeds to step S6, where the divided data is packetized by the multicast I / F 5a. From the packet with the smaller data number, in the case of FIG. 3, multicast is performed in the order of numbers 1, 2, 3,. be delivered. In step S7, after the total number of data (M) is distributed, a distribution end notification is multicast.

In parallel with the multicast distribution, the divided data management / control unit 6 on the transmission side monitors whether or not there is a content acquisition request from the user (or client) in step S11. When retrieving data from the receiving side is received by the data acquisition request receiving unit 7, the process proceeds to step S12, receives the packet number N ₀ designated by the client. The packet number N ₀ is the smallest number among the packet numbers received by the client by multicast distribution. Next, in step S13, the divided data management / control unit 6 notifies the client of the total number of data (M) via the unicast I / F 5b. Subsequently, the process proceeds to step S14, and the divided data is distributed in descending order from the designated number (packet number) N ₀ −1 via the unicast I / F 5b.

For example, in the case of M = 100, when N ₀ = 1, transmission is performed in descending order from 100, and when N ₀ = 85, transmission is performed in descending order from 84.

  In step S15, it is determined whether or not there has been a unicast transmission end request from the client. If there is an end request, the process proceeds to step S16 to end the unicast distribution. Subsequently, the process proceeds to step S17 to determine whether or not there is a request for retransmission of missing data from the client. If this determination is affirmative, the process proceeds to step S18, and the missing data is transmitted by unicast. In step S19, a determination is made as to whether or not a reception completion notification has been received from the client. If the result is negative, the process returns to step S17, whereas if the result is positive, the process ends.

  Next, the operation of the receiving side apparatus (FIG. 2) of this embodiment will be described.

  (1) For multicast reception only

  When the client issues a multicast reception instruction from the user I / F 18, this instruction is input to the divided data management / control unit 16, and the divided data management / control unit 16 receives the multicast data storage unit 12a via the multicast I / F 11a. Control to store multicast contents. As a result, multicast reception or multicast download becomes possible.

  (2) For unicast reception only

When the client issues a unicast content acquisition request instruction from the user I / F 18, the instruction is sent to the divided data management / control unit 16, from the content acquisition connection destination information extraction unit 17 to the transmission side address information, etc. Is transmitted to the data acquisition request receiving unit 7 on the transmission side via the data transmission request unit 19 and the unicast I / F 11b. (Then, it the judgment of step S11 in FIG. 4 described above is positive, followed by data number _{N 0} is received at step S12. Thereafter, the processing of steps S13~S19 are made, the client in step S13 (The total number of contents data (all data numbers) is notified and distributed to the unicast address of the receiving apparatus requested in step S14 in descending order.)

  On the other hand, the divided data management / control unit 16 on the receiving side controls to store the unicast contents received by the unicast I / F 11b in the unicast data storage unit 12b. As a result, unicast reception or unicast download becomes possible.

  (3) When receiving by both multicast reception and unicast reception

  (3-1) Multicast reception and unicast reception from the beginning of multicast broadcasting

At the beginning of content broadcast by multicast, when the client issues an instruction to acquire content by multicast and unicast from the user I / F 18, the unicast reception instruction and the smallest packet number (N ₀ = 1) is sent to the data acquisition request reception unit 7 on the transmission side via the divided data management / control unit 16, the data acquisition request unit 19, and the unicast I / F 11b.

Then, the transmitting side transmits data from N ₀ −1 in descending order, that is, in the order of the final numbers M, M−1, M−2,..., From the transmitting side unicast I / F 5b to the receiving side unicast I / F. Send to F11b.

  Since the divided data management / control unit 16 controls the multicast storage unit 12a and the unicast storage unit 12b to store data, the storage units 12a and 12b include the data as shown in FIG. 5 (a). , Multicast reception of data in ascending order from number 1 and unicast reception in descending order from number M are performed. In FIG. 5, for convenience of explanation, the speeds of multicast reception and unicast reception are considered to be the same.

  Here, the operation of the reception side apparatus after starting the multicast reception and the unicast reception will be described with reference to the flowchart of FIG. This operation is the same in (3-2) and (3-3) described below.

  In step S21, content data received by the multicast I / F 11a and the unicast I / F 11b are stored in the multicast data storage unit 12a and the unicast data storage unit 12b, respectively. In step S22, it is determined whether or not the packet number of the latest data received via unicast matches the number obtained by adding 1 to the packet number of the latest data received via multicast. When this determination is negative, the process returns to step S21, and reception of data in ascending order by the multicast I / F 11a and reception of data in descending order by the unicast I / F 11b are continued. When multicast distribution ends, reception of data by the multicast I / F 11a ends, and the packet number of the received data becomes Mth.

  As described above, the total number of divided data (M) of content, the serial number of the latest data received via unicast and the serial number of the latest data received via multicast according to the timing of reception via multicast and reception via unicast If the process of step S22 is not reliable, step S22 is changed to “Sequence number of latest data received via unicast = Sequence number of latest data received via multicast + 1? Or the serial number of the latest data received via unicast = the serial number of the latest data received via multicast? ”.

  If the determination in step S22 is affirmative, the process proceeds to step S23 to instruct the multicast I / F 11a and the unicast I / F 11b to end reception. In step S24, an end request for unicast transmission is sent to the transmission side. In step S25, the serial number and the total number of data are checked by combining the reception data from the multicast I / F 11a and the reception data from the unicast I / F 11b.

  In step S26, it is determined whether or not there is a missing packet number in the received data. If there is a missing packet, the process proceeds to step S27, and a retransmission request by unicast is sent to the transmission side. In step S28, the deficient data is received, and in step S29, the files are combined. When step S26 is negative, steps S27 and S28 are skipped. In step S30, it is determined whether or not the file is compressed. If the file is compressed, the process proceeds to step S31 to decompress the file. Next, the process proceeds to step S32, and the file (content) is stored in the file storage unit 15. In step S33, a data reception completion notification is sent to the transmission side. This completes a series of operations.

  In this case, the multicast broadcast can be acquired in half of the distribution time. In addition, the horizontal axis of Fig.5 (a) represents reception time.

  (3-2) When performing multicast reception and unicast reception from the middle of multicast broadcasting

When a client is watching a multicast broadcast and multicast reception and unicast reception are started from the middle, the reception mode by the multicast I / F 11a and the unicast I / F 11b is as shown in FIG. become. That is, if multicast broadcast is distributed from the beginning, and multicast reception and unicast reception are started simultaneously from the number N _{0 in} the middle, the multicast data accumulation unit 12a starts accumulation in ascending order from the packet number N _0. The unicast data accumulation unit 12b starts accumulation in descending order from the number (N ₀ −1). Note that when the unicast data storage unit 12b stores data up to the top, the storage is continued from the last data M. When the determination in step S22 becomes affirmative, an instruction to end reception is given to the multicast I / F 11a and the unicast I / F 11b.

Also in this case, the acquisition time of the multicast broadcast can be reduced to half of the distribution time. Further, it becomes possible to acquire data of packet numbers 1 to (N ₀ −1) missed by multicast reception by unicast reception.

  (3-3) When receiving a multicast broadcast from the beginning halfway and starting unicast reception from the middle

If the client has acquired the content from the beginning by multicast broadcasting and the reception of data by unicast participates after the packet number N ₀ , the reception by the multicast I / F 11a and the unicast I / F 11b is performed. The mode is as shown in FIG. That is, the multicast data accumulating unit 12a starts accumulating in ascending order from the packet number 1, and the unicast data accumulating unit 12b receives data in descending order from the packet number M starting from the time when the unicast reception is started. Is stored in the unicast data storage unit 12b. When the determination in step S22 becomes affirmative, an instruction to end reception is given to the multicast I / F 11a and the unicast I / F 11b.

In this case, reception ends when the data number of the multicast broadcast is (N ₀ + M) / 2, and the acquisition time can be shortened.

(3-4) When receiving by unicast before starting multicast broadcasting and starting multicast reception in the middle (Case 1)

  When the client starts unicast content reception on demand before the start of the multicast broadcast and the multicast reception starts from the beginning on the way, the reception mode by the multicast I / F 11a and the unicast I / F 11b is as follows: As shown in FIG. That is, the unicast data accumulating unit 12b starts accumulating in descending order from the packet number M, and the multicast data accumulating unit 12a starts accumulating when multicast broadcasting is started, that is, from the data of the packet number 1. When the serial number of the latest data received via unicast = (sequential number of the latest data received via multicast + 1) is established, the multicast I / F 11a and the unicast I / F 11b are instructed to end reception.

  Also in this case, it is clear that the reception time is shorter than the reception time in the case of only multicast reception or only in the case of multicast reception.

  FIG. 7 is a flowchart showing the operation of this embodiment. In step S41, content data is received via the unicast I / F 11b. In step S42, it is determined whether or not reception by the multicast I / F 11a has started. If this determination is negative, the process proceeds to step S43 to determine whether or not the packet number of the received data has become 1. If this determination is negative, the process returns to step S41.

When the determination in step S42 becomes affirmative, the process proceeds to step S45, and reception via the multicast I / F 11a is started. As a result, multicast reception and unicast reception are performed in parallel. In the next step S22, it is determined whether or not the packet number of the latest data received via unicast matches the number obtained by adding 1 to the packet number of the latest data received via multicast. If this determination becomes affirmative, the process proceeds to step S23, and an instruction to end reception is given to the unicast I / F 11b and the multicast I / F 11a. Thereafter, processing similar to that of FIG. 6 is performed. If the determination in step S43 is affirmative, the process proceeds to step S44, and the end of reception is notified to the unicast I / F 11b. Then, the process proceeds to step S24.
(Case 2)

Data received by multicast when the client has received the multicast broadcast from the beginning via the unicast I / Fs 5b and 11b and the multicast reception number is N ₀ (the unicast reception number is MN ₀ ). In the case of receiving, the manner of reception by the multicast I / F 11a and the unicast I / F 11b is as shown in FIG. 5E (where N ₀ <M / 2). That is, the unicast data accumulation unit 12b starts accumulation in descending order from the number M, the multicast data accumulation unit 12a receives data in ascending order from the time when multicast reception is started, and the received data is the multicast data accumulation unit 12a. Accumulated in. Thereafter, the multicast reception ends when (the serial number of the latest data received via unicast) and (the serial number of the latest data received via multicast + 1) match, but the unicast reception is number N ₀ . Get from data to number 1 data in descending order.

According to this embodiment, reception ends when the multicast broadcast data number is (M / 2 + N ₀ ), and the acquisition time can be shortened. In addition, data of numbers 1 to (N ₀ −1) missed by multicast reception can be acquired by unicast reception. If N ₀ ≧ M / 2, the multicast reception data overlaps with the unicast reception data, so the unicast reception is continued up to data number 1 without performing the multicast reception.

  Although the present invention has been described with the preferred embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit of the present invention.

It is a block diagram which shows the schematic structure of the transmission side apparatus of one Embodiment of this invention. It is a block diagram which shows the schematic structure of the receiving side apparatus of one Embodiment of this invention. It is a conceptual diagram of the data accumulate | stored in the storage part of the said transmission side apparatus. It is a flowchart which shows the outline | summary of operation | movement of the said transmission side apparatus. It is explanatory drawing of the receiving operation of the said receiving side apparatus. It is a flowchart which shows a part of operation | movement of the said receiving side apparatus. It is a flowchart which shows a part of operation | movement of the said receiving side apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... File storage part, 2 ... File compression part, 3 ... File division part, 4 ... Storage part, 5 ... Interface delivery means, 5a ... Multicast I / F, 5b ... Unicast I / F, 6 ... Divided data management / control unit, 7 ... Data acquisition request accepting unit, 11a ... Multicast I / F, 11b ... Unicast I / F, 12 ... Divided data storage unit, 12a ... Multicast data storage unit, 12b ... Unicast data storage unit, 13 ... File composition unit, 14 ... File decompression unit, 15 ... File storage unit , 16 ... divided data management / control unit, 17 ... content acquisition connection destination information extraction unit, 18 ... user I / F, 19 ... data transmission request unit.

Claims (8)

A dividing means for dividing the content to be transmitted into data of a predetermined size;
An accumulation unit for temporarily accumulating the divided data together with the serial number;
A control unit that controls reading of data stored in the storage unit;
Multicast transmission means for packetizing the data read from the storage unit and transmitting by multicast so that the data numbers attached to the packets are in ascending order;
Unicast transmission means for packetizing the data read from the storage unit and transmitting by unicast so that the data numbers attached to the packets are in descending order;
Connection destination information transmitting means for transmitting connection destination information for receiving the data transmitted by the multicast by the unicast,
Wherein, when there is a transmission request from the content receiving side sends the data from the storage unit, the unicast transmission means reads to be descending from a data transmission requested number, the transmission request When the received packet number is the head, the data is read in descending order from the last number of the content. When the number is other than the head, the data is read in descending order from the data of the number N-1, and the data is read to the head. When receiving the notification of the end of reception sent from the content receiving side, stop reading in descending order from the storage unit and stop the transmission from the unicast transmission means. A content transmitting apparatus characterized in that it is terminated. The content transmission device according to claim 1,
A content transmission apparatus further comprising schedule distribution means for designating a content to be multicast and its distribution time. A user I / F that specifies download from a list of contents to be multicast;
A multicast download means for downloading when the designated content is transmitted by multicast;
A multicast packet number acquisition means for acquiring a packet number received during multicast download;
Data transmission request means for requesting transmission of the designated content by unicast;
Unicast download means for downloading data transmitted in descending order by the unicast;
Unicast packet number acquisition means for acquiring a packet number received during unicast download;
A control unit that performs reception termination processing of the content when the multicast packet number acquired by the multicast packet number acquisition unit and the unicast packet number acquired by the unicast packet number acquisition unit are continuous or coincide with each other; Equipped,
The control unit, when the multicast packet number acquired by the multicast packet number acquisition unit and the unicast packet number acquired by the unicast packet number acquisition unit are continuous or coincident with each other, A content receiving apparatus that notifies the end of transmission. The content receiving device according to claim 3 ,
When the multicast packet number acquired by the multicast packet number acquisition unit and the unicast packet number acquired by the unicast packet number acquisition unit are continuous or coincide with each other, the control unit transmits at least the content to the multicast download unit. A content receiving apparatus that instructs to end reception. The content receiving device according to claim 3 ,
The control unit, when the multicast packet number acquired by the multicast packet number acquisition unit and the unicast packet number acquired by the unicast packet number acquisition unit are continuous or coincident with each other, A content receiving apparatus characterized by notifying the end of transmission and instructing at least the multicast download means to end content reception. The content receiving device according to any one of claims 3 to 5 ,
The control unit notifies the transmission side of the smallest number among the multicast packet numbers acquired by the multicast packet number acquisition unit at the time when there is a unicast transmission request instruction from the user I / F. A content receiving apparatus. In the content receiver in any one of Claim 3 thru | or 6 ,
A content receiving apparatus, further comprising a combining unit that combines the data downloaded by the multicast download unit and the unicast download unit and arranges the order of the data. A content transmission / reception system comprising a content transmission device and a content reception device,
The content transmission device includes:
A dividing means for dividing the content to be transmitted into data of a predetermined size;
An accumulation unit for temporarily accumulating the divided data together with the serial number ;
A first control unit that controls reading of data stored in the storage unit;
Multicast transmission means for packetizing the data read from the storage unit and transmitting by multicast so that the numbers assigned to the packets are in ascending order;
Unicast transmission means for packetizing the data read from the storage unit, and transmitting by unicast so that the numbers attached to the packets are in descending order;
Connection destination information transmitting means for transmitting connection destination information for receiving the data transmitted by the multicast by the unicast,
When there is a transmission request from the content receiving side, the first control unit reads the data from the storage unit in descending order from the data of the number requested for transmission, and sends it to the unicast transmission unit, When the packet number requested to be transmitted is the head, the data is read out in descending order from the last number of the content. When the number is other than the head, the data is read out in descending order from the data of the number N-1. When reading to the beginning, the process returns to reading of the last data, and when receiving a reception end notification sent from the content receiving side, reading from the storage unit in descending order is stopped and the unicast transmission means To stop sending
The content receiving device is:
A user I / F that specifies download from a list of contents to be multicast;
Multicast download means for downloading when the designated content is multicast transmitted by the multicast transmission means;
A multicast packet number acquisition means for acquiring a packet number received during multicast download;
Data transmission request means for requesting the connection destination to transmit the specified content by unicast;
Unicast download means for downloading data that has been unicast transmitted in descending order by the unicast transmission means;
Unicast packet number acquisition means for acquiring a packet number received during unicast download;
When the multicast packet number acquired by the multicast packet number acquisition unit and the unicast packet number acquired by the unicast packet number acquisition unit are continuous or coincide with each other, the transmission end of the content is notified to the content transmission side And at least a second control unit for instructing the multicast download means to end content reception,
When the multicast packet number acquired by the multicast packet number acquisition unit and the unicast packet number acquired by the unicast packet number acquisition unit are continuous or match, the second control unit transmits the content A content transmission / reception system characterized by notifying the end of content transmission.

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