JP2005167891A - Content server, content receiving apparatus, program and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely perform network reproduction even if temporary stop is changed into restart since there is a case that TCP connection is cut off if a user of a content receiving apparatus performs temporary stop while AV contents are divided and transmitted from a content server to the content receiving apparatus using a Range header of HTTP, or since there is a case that a user of a first content receiving apparatus can not view AV contents any more even after the user changes temporary stop into restart if another content receiving apparatus requests the AV contents during said transmission. <P>SOLUTION: An HTTP HEAD request message is periodically transmitted during temporary stop, so as not to cut TCP connection. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a content server, a content receiving device, a program, and a storage medium that transmit and receive AV content including images or audio via a network. In particular, the present invention relates to a content server, a content receiving device, a program, and a storage medium that can be easily released when the user of the content receiving device pauses viewing of AV content.

  There is HTTP (Hypertext Transfer Protocol) as a communication protocol used when AV content included in a content server is played back over a network by a content receiving device. Transmission / reception of AV content using HTTP is realized by a content server receiving an HTTP request message from a content receiving device and transmitting the content of the AV content in the HTTP response message.

  In version 1.0 of HTTP, it was only possible to request all one AV content with an HTTP request message. However, since version 1.1, only a part of AV content can be requested (for example, see Non-Patent Document 1). A method for acquiring only a part of an image file using this function has been proposed (see, for example, Patent Document 1).

  If the AV content partial acquisition is used, only a part of the AV content can be played, and fast-forward playback, rewind playback, skip playback, and the like of the moving image and sound via the network can be realized.

  Normally, HTTP is implemented as an upper protocol in a TCP (Transmission Control Protocol) layer, and therefore a TCP connection must be connected in order to send and receive HTTP messages. When AV content is to be played back over the network, a TCP connection is maintained between the content server and the content receiving device for the time required to distribute the AV content data.

  On the other hand, the number of AV contents that the content server can simultaneously distribute over the network depends on the storage media and resources of the content server. Some content servers can deliver only one AV content at a time, while others can deliver several at the same time. In general, an error message is transmitted to a content receiving apparatus that attempts to request network reproduction exceeding such a limit, or the request itself is ignored.

In network playback using HTTP, there are several possible methods for realizing pause when the user instructs pause during AV content playback. One is a method of stopping only output of AV content at the content receiving device without stopping transmission on the network (see, for example, Patent Document 2). According to this method, the content receiving apparatus is finally in a state where the reception buffer becomes full and cannot be received. In this case, since HTTP uses TCP, the content server is notified that the TCP reception window is 0.
JP 2001-101091 A JP 2001-242876 A R. Fielding et al., “Hypertext Transfer Protocol-HTTP / 1.1”, RFC 2616.

  However, the suspension of network playback in the above method cannot distinguish between the case where the content server has been in a pause state for a long time and the case where the content reception apparatus has entered an abnormal state. Therefore, if the user simply keeps the paused state for a long time, the content server may be mistaken for an abnormal state and disconnect the TCP connection. When the TCP connection is disconnected, if the content receiving apparatus tries to resume the network reproduction, the TCP connection must be started again. However, there is a possibility that AV content distribution to another content receiving apparatus may start while the TCP connection is disconnected. In some cases, the content server itself performs a reproduction operation locally.

  Generally, there is a limit to the number of AV contents that can be simultaneously distributed over the network by the content server. Depending on the content server, the number of local reproductions may be included in the limit number. This is due to restrictions on the network performance and the read performance of the storage device that stores AV content.

  If this happens, there is a possibility that the user of the content receiving apparatus may not be able to view the continuation even after resuming the network playback after the pause.

  The present invention solves the above-described conventional problems, and a content server, a content receiving device, a program, and a recording medium that can reliably perform network playback when the content receiving device pauses network playback and then resumes playback. The purpose is to provide.

A first content receiving apparatus of the present invention for solving the above problem is a content receiving apparatus that performs network playback of AV content including images or sounds stored in a content server using HTTP.
User input means for receiving an instruction regarding network reproduction from a user, request transmission means for transmitting an HTTP request message describing a request to the content server, and an HTTP response message that is a response from the content server to the HTTP request message Response receiving means for receiving,
The request transmission means sequentially transmits an HTTP request message requesting distribution of a part of AV content to the content server, and when an instruction to pause network playback is input to the user input means, the transmission of the HTTP request message is performed. And sends an HTTP request message including a HEAD method to the content server at a predetermined time interval,
The response receiving means receives an HTTP response message that is a response from the content server to an HTTP request message including the HEAD method.

  The second content receiving apparatus of the present invention further comprises connection management means for managing a TCP connection with the content server, and the connection management means if the response receiving means does not receive an HTTP response message for a predetermined time or more. Disconnects the TCP connection with the content server.

A first content server of the present invention is a content server that distributes AV content to one or more content receiving devices according to claim 1 or 2,
Request receiving means for receiving the HTTP request message, and connection management means for managing a TCP connection with the content receiving device,
The connection management means disconnects the TCP connection with the content receiving apparatus if the request receiving means does not receive an HTTP request message from the content receiving apparatus for a predetermined time or longer.

  The second content server of the present invention further comprises local reproduction means for locally reproducing AV content on the server body, and when the local reproduction means starts local reproduction of AV content, the connection management means The TCP connection with some or all of the above content receiving apparatuses is disconnected.

  A first program of the present invention receives a user input means for receiving an instruction relating to network reproduction from a user, a request transmission means for sending an HTTP request message, and an HTTP response message, which the content receiving device according to claim 1 has. A program for causing a computer to function as a response receiving means.

  A second program of the present invention receives a user input means for receiving an instruction relating to network reproduction from a user, a request transmission means for sending an HTTP request message, and an HTTP response message, which the content receiving device according to claim 2 has. This is a program for causing a computer to function as a response receiving means and a connection management means for managing a TCP connection with the content server.

  A third program of the present invention causes a computer to function as a request receiving means for receiving an HTTP request message and a connection management means for managing a TCP connection with the content receiving apparatus, which the content server according to claim 3 has. It is a program for.

  According to a fourth program of the present invention, there is provided a request receiving unit for receiving an HTTP request message, a connection management unit for managing a TCP connection with the content receiving device, and AV content stored in the server main body. This is a program for causing a computer to function as local playback means for local playback.

  A storage medium of the present invention is a recording medium carrying the program according to any one of claims 5 to 8, and is a recording medium that can be used by a computer.

  According to the present invention, it is possible to provide a content server, a content receiving device, a program, and a recording medium that can reliably perform network playback when the content receiving device pauses network playback and then resumes playback.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 3 is a configuration diagram of a network to which the present embodiment is applied. The content server 1 transmits AV content including an image or sound recorded in the storage unit 101 to the network 3 in response to a request from the content receiving device 2. The content receiving device 2 receives AV content from the content server 1 via the network 3 and reproduces it. Examples of AV content are moving images, still images, audio, and the like.

  FIG. 1 is a sequence diagram describing transmission / reception between the content server 1 and the content receiving device 2. Among HTTP messages exchanged in the sequence of FIG. 1, examples of (a) to (d) are shown in (a) to (d) of FIG.

  FIG. 2A shows an HTTP GET request message, in which the content reception apparatus 2 is recorded in the storage unit 101 of the content server 1 and works 1. Requesting from the 0th byte to the 499999th byte of mpg. In this example, work1. mpg is a moving image in the MPEG format. The storage unit 101 is preferably a non-volatile recording medium such as a hard disk, but can also be realized by a volatile recording medium.

  FIG. 2B shows an HTTP Partial Content response message, in which the content server 1 uses work1. This is an HTTP response message for transmitting the first 500000 bytes of mpg. This is a response to the HTTP GET request message in FIG. Below <Contents Data> in FIG. The data of mpg is included for 500000 bytes from the beginning.

  FIG. 2 (c) is an HTTP HEAD request message that includes the HEAD method in the header portion, which is transmitted by the content receiving device 2 during suspension, and FIG. 2 (d) is an HTTP response message that is transmitted by the content server 1 as a response thereto. It is. Content data is not included in the HTTP response message at this time.

  In FIG. 1, when trying to perform network playback in the content receiving device 2, the content receiving device 2 transmits an HTTP GET request message (a) including a Range header for each predetermined transfer unit, and the content server 1 performs AV An HTTP response message including the data of the designated part of the content, and HTTP Partial Content (b) are transmitted. This is sequentially repeated, and the AV content data received by the content receiving device 2 is decoded and reproduced.

  The second half of FIG. 1 shows an operation when the user of the content receiving device 2 instructs to pause. When a predetermined keep-alive time elapses after the temporary stop is instructed, the content receiving device 2 transmits an HTTP HEAD request message (c). The content of this HTTP HEAD request message is as follows. If the header part in FIG. 2C is GET as shown in FIG. A message requesting all of mpg. As a response, the content server 1 returns a work1. An HTTP response message having the same HTTP header part as that for transmitting all of mpg, but not including AV content data is transmitted (d).

  FIG. 4 is a block diagram showing an internal configuration of the content server 1. In FIG. 4, the storage means 101 stores AV content data such as moving images, still images, and audio. The request receiving unit 102 receives an HTTP request message from the content receiving device 2. The response transmission unit 103 generates and transmits an HTTP response message that is a response to the received HTTP request message. If necessary, the response transmission unit 103 acquires the requested data from the storage unit 101. The connection management unit 104 manages connection / disconnection of the TCP connection performed by the TCP transmission / reception unit 106. The local reproduction unit 105 locally reproduces the AV content stored in the storage unit 101 in the content server 1. The TCP transmission / reception means 106 transmits / receives data using the TCP protocol.

  FIG. 5 is a block diagram showing an internal configuration of the content receiving device 2. In FIG. 5, blocks having the same functions as the blocks constituting the content server 1 are denoted by the same reference numerals. The user input unit 201 receives a reproduction request, a pause request, an end request, and the like from the user. The request transmission unit 202 generates an HTTP request message and transmits it to the content server 1 via the TCP transmission / reception unit 106. The response receiving unit 203 receives an HTTP response message that is a response to the HTTP request message transmitted to the content server 1. If the message body includes AV content data, the response receiving unit 203 sends the AV content data to the reproducing unit 204. . The playback unit 204 receives, decodes, and plays back AV content data.

  Hereinafter, the operation of the content server 1 will be described.

  First, the operation of the content server 1 in normal content distribution will be described.

  FIG. 6 is a sequence diagram showing an internal operation of the content server 1 when AV content is distributed from the content server 1 to the content receiving device 2 over the network. When the TCP transmission / reception means 106 of the content server 1 receives a connection connection request from the network 3, the TCP transmission / reception means 106 performs connection connection processing. When the connection connection process is completed, the TCP transmission / reception unit 106 notifies the connection management unit 104 of the completion of the TCP connection connection. The connection management unit 104 notifies the request reception unit 102 of the completion of TCP connection connection.

  Thereafter, when the TCP transmission / reception means 106 receives the HTTP GET request message, it transmits it to the request reception means 102. The request reception unit 102 notifies the response transmission unit 103 of the requested content. The response transmission unit 103 sends an AV content request including the name and range of the requested AV content name to the storage unit 101, and the storage unit 101 returns the AV content data of the requested part. The response transmission unit 103 generates an HTTP response message including the received AV content data, and transmits the HTTP response message to the network 3 via the TCP transmission / reception unit 106. These operations are repeated each time an HTTP GET request message is received.

  Next, the operation of the content server 1 when the network reproduction in the content receiving device 2 is temporarily stopped will be described.

  FIG. 7 is a sequence diagram showing the operation of the content server 1 when the network playback in the content receiving device 2 is temporarily stopped. When the TCP transmission / reception means 106 receives the HTTP HEAD request message from the content reception device 2, it transmits it to the request reception means 102. The request reception unit 102 notifies the response transmission unit 103 of the requested content. The response transmission unit 103 inquires of the storage unit 101 about the attribute (length, etc.) of the AV content included in the HTTP HEAD request message. The storage unit 101 returns the attribute of the corresponding AV content. The response transmission unit 103 generates an HTTP response message based on the received AV content attribute, and transmits the HTTP response message to the network 3 via the TCP transmission / reception unit 106. These operations are repeated each time an HTTP HEAD request message is received.

  Next, the operation of the content server 1 when a connection disconnection request is received from the content receiving device 2 will be described.

  FIG. 8 is a sequence diagram showing an operation when the content server 1 receives a connection disconnection request from the content receiving device 2 during network distribution or the like. When the TCP transmission / reception means 106 receives a connection disconnection request from the content receiving device 2, it performs a connection disconnection process. When the connection is disconnected, the TCP transmission / reception unit 106 notifies the connection management unit 104 of the disconnection of the TCP connection. The connection management unit 104 notifies the request reception unit 102 of disconnection of the TCP connection.

  Next, an operation when AV content is reproduced locally in the content server 1 will be described.

  FIG. 9 is a sequence diagram showing an internal operation of the content server 1 when the content server 1 reproduces AV content locally. When the local playback unit 105 completes preparation for local playback, the local playback unit 105 notifies the connection management unit 104 of a connection disconnection request. The connection management unit 104 notifies the TCP transmission / reception unit 106 of a connection disconnection request. The TCP transmission / reception unit 106 performs connection disconnection processing and notifies the connection management unit 104 of the completion of connection disconnection. The connection management unit 104 notifies the request reception unit 102 and the local reproduction unit 105 that the connection has been disconnected. The local reproduction means 105 starts local reproduction after receiving the notification of the disconnection completion.

  Note that the example of FIG. 9 is an example of the content server 1 in which the total number of local and network playbacks is limited to one, but the content server 1 can play back two or more AV contents. Good. In that case, the total number of AV content playbacks has reached the limit, and before starting playback locally, one of the TCP connections used during network playback is disconnected. In such a case, local reproduction may not be possible. In that case, the user may or may not be notified of the reason for the inability to reproduce by displaying on a display or the like. Moreover, you may cut | disconnect some or all of the TCP connection currently utilized during network reproduction | regeneration.

  Next, an operation when the content server 1 cannot receive an HTTP request message from the content receiver 2 for a predetermined time or more will be described.

  FIG. 10 is a sequence diagram showing an internal operation of the content server 1 when an HTTP request message cannot be received from the content receiving device 2 for a predetermined time or more. When the request receiving unit 102 detects a non-communication state in which an HTTP request message cannot be received for a predetermined time or more, the request receiving unit 102 requests the connection management unit 104 to disconnect the TCP connection. The connection management unit 104 requests the TCP transmission / reception unit 106 to disconnect the TCP connection. The TCP transmission / reception unit 106 performs connection disconnection processing and notifies the connection management unit 104 of completion of TCP connection disconnection. The connection management unit 104 notifies the request reception unit 102 of the completion of disconnection.

  Hereinafter, the operation of the content receiving device 2 will be described.

  First, the operation of the content receiving apparatus 2 when distributing AV content from the content server 1 to the content receiving apparatus 2 will be described.

  FIG. 11 is a sequence diagram showing the internal operation of the content receiving device 2 when AV content is distributed from the content server 1 to the content receiving device 2 over the network.

  When the user inputs the content of AV content and the start position (after 30 minutes, etc.) to the user input means 201, the user input means 201 designates the AV content name and start position and requests the request transmission means 202 to start playback. To do. The request transmission unit 202 requests the connection management unit 104 to establish a TCP connection. The connection management unit 104 requests the TCP transmission / reception unit 106 to establish a TCP connection, and the TCP transmission / reception unit 106 executes a connection connection process. When the connection connection process is completed, the TCP transmission / reception unit 106 notifies the connection management unit 104 of the completion of the TCP connection connection. The connection management unit 104 notifies the request transmission unit 202 of the completion of the TCP connection connection.

  When the TCP connection connection is completed, the request transmission unit 202 generates an HTTP GET request message from the requested AV content name and start position, and transmits it to the network 3 via the TCP transmission / reception unit 106. At this time, a Range header is included in the HTTP GET request message so as to be divided into predetermined transfer units, and the requested transfer unit portion is designated. When the TCP transmission / reception unit 106 receives the HTTP response message transmitted from the connection server 1, the TCP transmission / reception unit 106 transmits the message to the response reception unit 203. The response receiving unit 203 extracts AV content data from the received HTTP response message and sends it to the playback unit 204. The reproduction means 204 decodes and reproduces the received AV content data. Thereafter, the processing from the transmission of the HTTP GET request message to the reproduction of the content is repeated until all the requested content information is received.

  Next, the operation of the content receiving device 2 when playback is paused according to a user instruction will be described.

  FIG. 12 is a sequence diagram showing an internal operation of the content receiving device 2 when AV content is distributed from the content server 1 to the content receiving device 2 and the user of the content receiving device 2 pauses playback.

  When the user input unit 201 receives a pause request from the user, the user input unit 201 instructs the request transmission unit 202 to pause. The request transmission unit 202 starts a keep alive timer. Each time a predetermined keep alive time elapses, an HTTP HEAD request message is transmitted to the content server 1 via the TCP transmission / reception means 106. When the TCP transmission / reception means 106 receives the HTTP response message from the content server 1, it notifies the response reception means 203. These processes are repeated every time a predetermined keep alive time elapses.

  Next, the operation of the content receiving device 2 at the end of network reproduction will be described.

  FIG. 13 is a sequence diagram for explaining the operation of the content receiving apparatus 2 when the network reproduction reaches the end of the AV content.

  When the response receiving unit 203 detects that the end of content is included in the received HTTP response message, the response receiving unit 203 requests the connection management unit 104 to disconnect the TCP connection. The connection management unit 104 requests the TCP transmission / reception unit 106 to disconnect the TCP connection. The TCP transmission / reception unit 106 executes connection disconnection processing and notifies the connection management unit 104 of the completion of disconnection of the TCP connection. The connection management unit 104 notifies the response reception unit 203 of the completion of disconnection of the TCP connection. The response receiving unit 203 instructs the playback unit 204 to end playback, and the playback unit 204 performs playback end processing.

  Next, an operation of the content receiving apparatus when receiving a TCP connection disconnection request from the content server 1 during content reception will be described.

  FIG. 14 is a sequence diagram showing an internal operation of the content receiving apparatus 2 when a TCP connection disconnection request is received from the content server 1 during reception of AV content.

  When the TCP transmission / reception unit 106 receives a connection disconnection request from the content server 1, it performs connection disconnection processing and notifies the connection management unit 104 of disconnection of the TCP connection. The connection management unit 104 notifies the request transmission unit 202 of disconnection of the TCP connection and instructs the reproduction unit 204 to end reproduction. The playback unit 204 performs playback end processing in accordance with an instruction from the connection management unit 104.

  Next, the operation of the content receiving device 2 when an HTTP response message cannot be received from the content server 1 for a predetermined time or more will be described.

  FIG. 15 is a sequence diagram showing an internal operation of the content receiving device 2 when an HTTP response message cannot be received from the content server 1 for a predetermined time or longer.

  When the response receiving unit 203 detects a non-communication state in which an HTTP request message cannot be received for a predetermined time or more, it requests the connection management unit 104 to disconnect the TCP connection. The connection management unit 104 requests the TCP transmission / reception unit 106 to disconnect the connection. The TCP transmission / reception unit 106 executes connection disconnection processing and notifies the connection management unit 104 of the completion of disconnection of the TCP connection. The connection management unit 104 notifies the response reception unit 203 of the completion of the disconnection, and the response reception unit 203 instructs the reproduction unit 204 to end the reproduction. The playback unit 204 performs playback end processing in accordance with an instruction from the response receiving unit 203.

  Next, the operation of the content receiving device 2 when the pause is canceled will be described.

  FIG. 16 is a sequence diagram illustrating an internal operation of the content receiving device 2 when the user of the content receiving device 2 releases the pause while the network playback is paused.

  During the temporary stop shown in the first half of FIG. 16, as described with reference to FIG. 11, the HTTP HEAD request message is transmitted and the response HTTP response message is repeatedly received. At this time, when the user releases the suspension, the user input unit 201 accepts the suspension release and requests the request transmission unit 202 to release the suspension. The request transmission unit 202 transmits an HTTP request message for requesting data subsequent to the AV content data included in the HTTP response message received before suspension to the content server 1 via the TCP transmission / reception unit 106. When the TCP transmission / reception means 106 receives the HTTP response message, it sends it to the response reception means 203, and the response reception means 203 sends the AV content data contained in the received HTTP response message to the reproduction means 204. The reproduction means 204 decodes and reproduces the received data. The above is repeated from reception of the HTTP GET request message.

  As described above, in the content receiving apparatus of the present invention, the HTTP HEAD request message is periodically transmitted during the pause, so that the TCP connection is not disconnected, and the user can reliably cancel the pause and resume the reproduction. You can watch the continuation. Furthermore, the content receiving apparatus of the present invention can detect that communication with the content server has been interrupted due to disconnection of the network cable or the like while maintaining the above-described effect, and can perform appropriate abnormality processing.

  As a secondary effect, if the AV content that has been viewed until now is lost for some reason during the pause, the content receiving device knows this by responding to the HTTP HEAD request message. , Can notify the user.

  In addition, since the content server of the present invention can determine whether the content receiving apparatus is paused or abnormal due to a user operation, if it is paused, an AV content distribution request from another content receiving apparatus or local Regeneration can be suppressed, and appropriate abnormal processing can be performed in an abnormal state.

  In the above embodiment, for example, a relay device exists between the content server and the content receiving device, an HTTP request message is transmitted from the content receiving device to the relay device, the relay device accesses the content server, AV content may be acquired and transmitted to the content receiving device. That is, it is not always necessary for the content server and the content receiving device to directly transmit and receive data via the network.

  In the present invention, an example in which only one content receiving device is connected to the content server has been described. However, the present invention can be applied even if there are two or more content receiving devices. In this case, when the content server performs local reproduction, the TCP connection with some or all of the two or more connected receiving apparatuses may be disconnected.

  The program of the present invention is a program for causing a computer to execute all or part of the above-described content server and content receiving apparatus of the present invention, and is a program that operates in cooperation with the computer.

  The recording medium of the present invention is a recording medium carrying a program for causing a computer to execute all or part of the above-described content server and content receiving apparatus of the present invention, and is readable and read by a computer. The program is a recording medium used in cooperation with the computer.

  Further, one usage form of the program of the present invention may be an aspect in which the program is recorded on a computer-readable recording medium and operates in cooperation with the computer.

  The recording medium includes a ROM and the like, and the transmission medium includes a transmission medium such as the Internet, light, radio waves, sound waves, and the like.

  Further, as described above, the configuration of the present invention may be realized by software or hardware.

  Use can be extended to standard or non-standard protocols other than HTTP.

Sequence diagram between a content server and a content receiving device in Embodiment 1 of the present invention The figure which shows the HTTP message contents Figure showing network configuration FIG. 2 is a block diagram showing the internal configuration of the content server 1 The block diagram which shows the internal structure of the content receiver 2 same as the above The sequence diagram showing the internal operation of the content server 1 during network playback The sequence diagram showing the operation of the content server 1 when the network playback is paused The sequence diagram showing the operation of the content server 1 when a connection disconnection request is received from the content receiving device 2 FIG. 3 is a sequence diagram showing an internal operation of the content server 1 when AV content is reproduced locally on the content server 1 Similarly, a sequence diagram illustrating an internal operation of the content server 1 when an HTTP request message cannot be received from the content receiving device 2 for a predetermined time or more. Sequence diagram showing internal operation of content receiving apparatus 2 during network playback The sequence diagram showing the internal operation of the content receiving device 2 when the network playback is paused The sequence diagram explaining the operation of the content receiving apparatus 2 when the network playback reaches the end of the AV content The sequence diagram showing the internal operation of the content receiving apparatus 2 when a TCP connection disconnection request is received from the content server 1 during reception of AV content, etc. Similarly, a sequence diagram showing an internal operation of the content receiving device 2 when an HTTP response message cannot be received from the content server 1 for a predetermined time or longer. Similarly, a sequence diagram showing an internal operation of the content receiving device 2 when the user of the content receiving device 2 releases the pause while the network reproduction is paused

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Content server 2 Content receiving apparatus 3 Network 101 Storage means 102 Request receiving means 103 Response sending means 104 Connection management means 105 Local reproduction means 106 TCP transmission / reception means 201 User input means 202 Request transmission means 203 Response reception means 204 Reproduction means

Claims (9)

A content receiving apparatus that performs network playback of AV content including images or audio stored in a content server using HTTP,
User input means for receiving an instruction regarding network reproduction from a user, request transmission means for transmitting an HTTP request message describing a request to the content server, and an HTTP response message that is a response from the content server to the HTTP request message Response receiving means for receiving,
The request transmission means sequentially transmits an HTTP request message requesting distribution of a part of AV content to the content server, and when an instruction to pause network playback is input to the user input means, the transmission of the HTTP request message is performed. And sends an HTTP request message including a HEAD method to the content server at a predetermined time interval,
The content receiving apparatus, wherein the response receiving means receives an HTTP response message that is a response from the content server to an HTTP request message including the HEAD method. Connection management means for managing a TCP connection with the content server is further provided, and if the response receiving means does not receive an HTTP response message for a predetermined time or more, the connection management means disconnects the TCP connection with the content server. The content receiving apparatus according to claim 1, wherein: A content server for delivering AV content to one or more content receiving devices according to claim 1 or 2,
Request receiving means for receiving the HTTP request message, and connection management means for managing a TCP connection with the content receiving device,
The connection management unit disconnects the TCP connection with the content receiving device if the request receiving unit does not receive an HTTP request message from the content receiving device for a predetermined time or longer. . The apparatus further comprises local reproduction means for locally reproducing AV content on the server body, and when the local reproduction means starts local reproduction of AV content, the connection management means is a part of the one or more content receiving devices. 4. The content server according to claim 3, wherein all or all TCP connections are disconnected. The computer functions as a user input unit that receives an instruction regarding network reproduction from a user, a request transmission unit that transmits an HTTP request message, and a response reception unit that receives an HTTP response message, which the content reception device according to claim 1 has. Program for. A user input means for receiving an instruction relating to network reproduction from a user, a request transmission means for transmitting an HTTP request message, a response reception means for receiving an HTTP response message, and the content server, the content receiving apparatus according to claim 2 A program for causing a computer to function as connection management means for managing TCP connections. A program for causing a computer to function as a request receiving unit that receives an HTTP request message and a connection management unit that manages a TCP connection with the content receiving device, which the content server according to claim 3 has. 4. A request receiving means for receiving an HTTP request message, a connection management means for managing a TCP connection with the content receiving apparatus, and a local playback means for locally playing back AV content on the server body. , A program to make the computer function as. A recording medium carrying the program according to claim 5, which can be used by a computer.

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