JP2007194762A - Content transmitter and content receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the excessive acquisition of resources and deterioration in image quality in the case of transmitting contents with different bit rates by using a wired or wireless LAN. <P>SOLUTION: When this content transmitter transmits and receives contents with different bit rates to and from the content receiver via a network by using the wired or wireless LAN, the size of a transmission window and the size of transmission data of the content transmitter and the size of a reception window and the size of received data of the contents receiver are revised. Thus, the deterioration of the image quality and the excessive consumption of the resources used by the transmitter/receiver at contents transmission/reception can be prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmission device and a reception device suitable for transmitting and receiving content such as video and audio via a network.

  With the development of processing capacity such as the computing speed and storage capacity of personal computers (hereinafter referred to as PCs), the capacity of hard disk drives (hereinafter referred to as HDDs) built into PCs is also increasing. Under these circumstances, it is now possible to record TV broadcast programs using a HDD and view them on a PC display even on a PC with a rank that is used in general households. I came. On the other hand, due to the low price of large-capacity HDDs, HDD recording devices that have built-in HDDs and digitally record video and audio information are also appearing as home recording devices, and discs are used as recording media. Ease of use due to the use is attracting attention.

  In video recorders and PCs that use HDDs as described above, video and audio information is recorded on the HDD fixed in the device, so if you want to watch the recorded program in another room, the device Carrying video / audio information at the medium level, which can be carried with a plurality of recording / playback devices that use replaceable media such as VTRs, has been difficult to carry.

  Therefore, a wired or wireless LAN (Local Area Network) interface is installed in such a recording device, and it is sent to other PCs or receiving devices via the network to view the recorded video / audio information anywhere in the house. An example of an apparatus that can be used is described in Non-Patent Document 1. However, in this non-patent document 1, when transmitting / receiving content at a bit rate exceeding the transfer rate of the network, transmission / reception is performed after down-conversion, so that the image quality deteriorates. Therefore, the optimal data is determined by determining the transmission / reception processing size from the setting value of MTU (Maximum Transfer Unit) for each application, optimizing the transmission / reception buffer size from the determined transmission / reception processing size, and reflecting it in the sliding window and maximum segment size. It is disclosed that long data transfer is possible (Patent Document 1).

JP 2000-124950 A (page 3 [0009]-[0010]) Toshiba Review, Vol. 57 No9. (Page 6-7)

Generally, TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are used for transmitting and receiving contents via a network. When content with different bit rates, such as SD images and HD images, are sent and received using the above protocol, content data transfer processing, transmission data processing, and reception data processing on the network are constant. For example, when SD images are supported, there is a problem that image quality deteriorates when HD images are transmitted. If the SD image is transmitted when the HD image is supported, the resources used by the content transmission device and the content reception device are excessively consumed.
An object of the present invention is to provide a content transmitting apparatus and a content receiving apparatus that can solve the above-described problems such as deterioration in image quality and excessive consumption of work memory resources.

  In order to solve the above problems, in the present invention, a network transmission processing means for transmitting data to a content receiving apparatus via a network, a network transmission setting means and a transmission content control means for transmitting data to be transmitted to the content receiving apparatus. Content transmission control means for instructing, network transmission setting means for receiving the instruction from the content transmission control means and setting the first transmission method in the network transmission processing means, and data for storing the content to be transmitted to the content receiving device Storage means and transmission content control means for receiving data from the data storage means in accordance with a second transmission method in response to an instruction from the content transmission control means and supplying the data to the network transmission processing means. To the content receiver via The first transmission method and the second transmission method are determined for each content to be transmitted, and at least one of the network transmission setting unit and the transmission content control unit is instructed, and the first transmission method is received. The network transmission setting means reflects the instruction content in the transmission window size of the network transmission control means, and the transmission content control means receiving the instruction of the second transmission method processes the content data for transmitting the instruction content to the content receiving device. By reflecting on the size, it is possible to prevent deterioration of the image quality of the content to be transmitted and excessive consumption of resources used by the content transmitting apparatus when transmitting the content.

  In the present invention, the network reception processing means for receiving data from the content transmission apparatus via the network, and the content reception control for instructing the network reception setting means and the reception content control means about the reception method of the data received from the content transmission apparatus. Means, a network reception setting means for setting the first reception method in the network reception processing means upon receiving an instruction from the content reception control means, and a network reception according to the second reception method upon receiving an instruction from the content reception control means Receiving content control means for acquiring data from the processing means and supplying the data to the content reception control means, wherein the content reception control means includes the first reception method and the first reception method for each content received from the content transmission device via the network. Determine the second receiving method, it Instructing at least one of the network reception setting means and the reception content control means, the network reception setting means receiving the instruction of the first reception method reflects the instruction content in the reception window size of the network reception control means, The received content control means that has received the instruction of the second receiving method reflects the instruction contents in the processing size of the content data received from the network reception processing means, and the content receiving device receives the content when the content receiving apparatus receives the content. Prevent excessive consumption of resources used.

  According to the present invention, when transmitting content of different bit rates using a wired or wireless LAN, the content transmission device can prevent image quality degradation and excessive acquisition of resources used by the device for content transmission / reception It is possible to provide a receiving device.

  Embodiments of the present invention will be described with reference to the drawings.

Example 1 which is the first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration of a content transmission device 100 and a content reception device 200 according to Example 1 which is an embodiment of the present invention. The content transmission device 100 and the content reception device 200 are connected to each other via a LAN 300. Has been.
In the content transmission apparatus 100, 101 is a content transmission control circuit that controls the entire content transmission apparatus 100 during content transmission, 102 is a network transmission processing circuit that transmits content data to other apparatuses via the LAN 300, and 103 is content transmission control. A network transmission setting circuit that reflects the contents of the instruction 1 received from the circuit 101 to the network communication processing circuit 102, and 104 reflects the contents of the instruction 2 received from the content transmission control circuit 101 to transmit the transmission data to the network transmission processing circuit 102. A transmission content control circuit 105 for transmitting is a data storage unit in which digital content received by receiving a broadcast and digital content downloaded from the Internet are stored.

  In the content receiving device 200, 201 is a content reception control circuit that controls the entire content receiving device 200 when content is received, 202 is a network reception processing circuit that receives content data from other devices via the LAN 300, and 203 is content reception control. A network reception setting circuit 204 that reflects the contents of the instruction 3 received from the circuit 201 to the network reception processing circuit 202, and 204 reflects the contents of the instruction 4 received from the content reception control circuit 201 to transfer the received data to the network reception processing circuit 202. It is a received content control circuit received from.

FIG. 2 shows a configuration example of a home LAN including the content transmission device 100 and the content reception device 200. One content transmission device 100 and two content reception devices 200a and 200b are connected to a network hub device 400 by a wired LAN cable, and the network hub device 400 is connected to a router 500.
The router 500 is connected to the Internet via a modem or a photoelectric converter. The content transmitting device 100, the content receiving devices 200a and 200b, and the router 500 each have an IP address that identifies itself on the LAN. A 48-bit MAC (Media Access Control) address is given in advance to the interface between each network transmission processing circuit 102 and the LAN 300 of the network reception processing circuit 202 at the time of manufacture.

  For example, the router 500 is operated as a DHCP server by DHCP (Dynamic Host Configuration Protocol), which has been widely used for automatic address setting in the network, and the IP address of each device is set. Should be allocated. When IPv6 (Internet Protocol Version 6) is used, each device can determine its own IP address from the upper 64 bits of the IP address of the router 500 and the MAC address by a method called stateless automatic setting.

  The LAN configuration in FIG. 2 is merely an example, and three or more content receiving apparatuses may be connected. Also, two or more content transmission devices may be connected. In this case, it is possible to transmit content from each content transmission device to the content reception device as long as the LAN bandwidth permits. Note that the minimum necessary configuration in the present invention is a state in which one content transmitting device and one content receiving device are connected to the LAN.

  The operation of content transmitting apparatus 100 of the present embodiment having the above configuration will be described. In the content transmission apparatus 100, the content transmission control circuit 101 is, for example, a control application that operates the content transmission apparatus 100. The content transmission control circuit 101 instructs the network transmission setting circuit 103 according to, for example, the bit rate of the content to be transmitted to the content reception apparatus 200. The first transmission method and the second transmission method instructed to the transmission content control circuit 104 are changed.

  Upon receiving the instruction 1 from the content transmission control circuit 101, the network transmission setting circuit 103 changes the transmission window size setting 1 of the network transmission processing circuit 102. The transmission content control circuit 104 changes the data size acquired from the data storage unit 105 in one transmission process according to the instruction 2 from the content transmission control circuit 101.

  FIG. 3 is an example showing this embodiment in more detail. Reference numeral 1021 denotes a reference model layer 4 (transport layer) of the network structure design policy “OSI (Open Systems Interconnection)” for realizing data communication between different models established by the International Organization for Standardization (ISO). For example, TCP or UDP. Reference numeral 1022 denotes a transmission window that determines a buffer that can be transmitted to the content transmission apparatus 200 at one time. The size of the transmission window 1022 is determined by the network transmission setting circuit 103 that has received an instruction 1 from the content transmission control circuit 101. Reference numeral 1023 denotes transmission data indicating the size of data to be written in the transmission window 1022 by a single transmission process.

Reference numeral 1024 denotes the OSI reference model layer 3 (network layer), for example, IP (Internet Protocol). The above 1021 to 1024 together correspond to the network transmission processing circuit 102.
Reference numeral 1023 denotes transmission data for setting a size for writing data acquired from the data storage unit 105 in the transmission window size 1022. Reference numeral 1024 denotes the OSI reference model layer 3 (network layer), for example, IP (Internet Protocol). The above 1021 to 1024 together correspond to the network transmission processing circuit 102.

A description will be given of processing when the content transmitting apparatus 100 transmits contents with different bit rates, for example, SD video (8 Mbps) and HD video (24 Mbps) to the content receiving apparatus 200.
FIG. 4 shows an example of values when the content transmission control circuit 101 gives instructions 1 and 2 to the network transmission setting circuit 103 and the transmission content control circuit 104 for each of the SD video and the HD video. When transmitting the SD video, the content transmission control circuit 101 instructs 21 KByte to the network transmission setting circuit 103 as the first transmission method, and instructs 21 KByte to the transmission content control circuit 104 as the second transmission method. The network transmission setting circuit 103 sets, for example, 21 KByte instructed by the content transmission control circuit 101 to the size of the transmission window 1022 of TCP / UDP (1021). On the other hand, the transmission content control circuit 104 receives the 21 KByte instruction 2 from the content transmission control circuit 101, acquires the content data to be transmitted for each 21 KByte from the data storage unit 105, and writes it in the transmission data 1023 of the transmission window 1022.

  When transmitting an HD video, the network transmission setting circuit 103 sets the size of the transmission window 1022 to 64 Kbytes instructed 1 by the content transmission control circuit 101 and the transmission content control circuit 104 is the content transmission control circuit 101 as described above. The content data is acquired from the data storage unit 105 every 64 KBytes specified by the instruction 2 and written in the transmission data 1023.

  On the other hand, the content receiving device 200 acquires information on the content to be received before receiving the content from the content transmitting device 100. As the information acquisition method of this content, for example, the “HEAD” method of HTTP (Hyper Text Transfer Protocol) may be used to acquire the detailed information of the content received from the header of the HTTP response. After acquiring the detailed information of the content, the content reception apparatus 200 receives the TCP 3 in accordance with the instruction 3 from the content reception control circuit 201 every time it receives content with a different bit rate, as with the content transmission apparatus 100 described above. The reception content control circuit 204 receives the data size specified by the content reception control circuit 201 from the reception data 2023 of the reception window 2022, and sets the size of the reception window 2022 of / UDP (2021). Data is displayed on a display device such as a TV monitor via 201.

FIG. 5 shows an example of a procedure at the time of content transmission / reception by the content transmission device 100 and the content reception device 200 in the present embodiment. The content receiving device 200 establishes (600) a connection for acquiring content information with the content transmitting device 100. After the connection is established, the content receiving apparatus 200 transmits a content information acquisition request (601) to the content transmitting apparatus 100.
This content information acquisition request (601) is made using, for example, the above-described HTTP “HEAD” method. Upon receiving the content information acquisition request, the content transmitting apparatus 100 transmits a reception confirmation response (602) to the content receiving apparatus 200, and transmits the requested content information (603). In this content information, for example, the media type, content length, bit rate, etc. of the content to be transmitted are described.

  After the content receiving apparatus 200 receives the content information, it transmits a reception confirmation response (604) to the content transmitting apparatus 100. The content transmitting apparatus 100 once sets the size of the transmission window 1022 according to the bit rate of the content to be transmitted as described above. The content receiving apparatus 200 sets the size of the reception window 2022 and the size of the reception data 2023 to be received at a time according to the bit rate of the content to be received as described above, A connection for content transmission / reception is established between the content transmission device 100 and the content reception device 200 (700).

  At this time, the previously established connection (600) for acquiring content information may or may not be closed. After the content transmission / reception connection (700) is established between the content transmission device 100 and the content reception device 200, the content reception device 200 transmits a content request (701) to the content transmission device 100. The content transmitting apparatus 100 transmits a reception confirmation response (702), and transmits the requested content to the content receiving apparatus 200 (703).

  As described above, according to the present embodiment, when transmitting / receiving content with different bit rates (explained as SD video and HD video in the present embodiment), at the time of content transmission / reception at a high bit rate, for example, content transmission apparatus 100 transmits By greatly adjusting the size of the window 1022 and the size of the transmission data 1023 and adjusting the size of the reception window 2022 and the size of the reception data 2023 in the content receiving apparatus 200, the content transmission / reception is performed, for example, by TCP or HTTP on the IP network. When receiving data, the number of reception responses ACK (ACKnowledgement) from the content receiving apparatus 200 for data transmission is reduced, and the throughput is improved.

  The processing of the content transmitting apparatus 100 and the content receiving apparatus 200 also improves the processing performance because the number of data transmissions / receptions between TCP / UDP and the upper application is reduced. Accordingly, it is possible to prevent deterioration in image quality due to content transmission / reception. On the other hand, at the time of content transmission / reception at a low bit rate, for example, the size of the transmission window 1022 and the size of the transmission data 1023 are adjusted to be small in the content transmission device 100 and the size of the reception window 2022 and the size of the reception data 2023 are small in the content reception device 200. By adjusting, it is possible to prevent the content transmission device 100 or the content reception device 200 from consuming excessive resources such as a work memory used for content transmission / reception.

  Further, although the present embodiment has been described by focusing on the bit rate of the content, even if the size of the transmission / reception window and the size of the transmission / reception data are changed according to the genre or category of the content, such as animation, sports, movies, etc. An effect is obtained. FIG. 6 shows setting values for the size of the transmission / reception window and the size of transmission / reception data depending on the genre or category of the content. For example, for content with little movement such as animation, the size of the transmission / reception window and the size of transmission / reception data are adjusted to be small. For content such as a movie with complicated movement, the size of the transmission / reception window and the size of transmission / reception data are adjusted to be small.

Next, Example 2 which is 2nd embodiment is demonstrated using drawing.
In the present embodiment, the network traffic on the LAN 300 is monitored and the window size and the transmission / reception processing size are set according to the traffic to prevent the deterioration of the image quality of the content to be transmitted / received. FIG. 7 is a diagram showing the second embodiment, and the same components as those described in the first embodiment are denoted by the same reference numerals.
In the figure, reference numeral 106 in the content transmitting apparatus 100 is a timer circuit that measures the time from when a specific packet is transmitted to the content receiving apparatus 200 until the reception confirmation response is received from the content receiving apparatus 200. Similarly to the above, the content receiving apparatus 200 transmits a specific packet from the content receiving apparatus 200 to the content transmitting apparatus 100 and measures the time until the reception confirmation response is returned from the content transmitting apparatus 100. It comprises.

  FIG. 8 shows an example of a procedure for measuring the time from the specific packet transmission to the reception confirmation response reception between the content transmission device 100 and the content reception device 200. In the timer circuit 106 of the content transmission device 100, for example, a time T1 from the start of transmission of content information (603) to the content reception device 200 until reception of a reception confirmation response (604) from the content reception device 200 is measured, and content transmission is performed. The control circuit 101 grasps the network traffic between the content receiving devices 200 from T1. On the other hand, in the content receiving apparatus 200, the timer circuit 206 measures, for example, a time T2 from when the content information acquisition request (601) is transmitted to the content transmitting apparatus 100 until the reception confirmation response 602 is received from the content transmitting apparatus 100.

  The content reception control circuit 201 grasps network traffic between the content transmission apparatuses 100 from T2. Thereafter, T1 and T2 are shared between the content transmitting apparatus 100 and the content receiving apparatus 200 (605). Thereafter, T1 and T2 are compared in each device. For example, when the comparison result between T1 and T2 is T1> T2, the content reception control circuit 201 of the content reception apparatus 200 determines the optimal reception window 2022 size and reception data 2023 size from the T1 value measured by the content transmission apparatus 100. Set to. For example, when the comparison result between T1 and T2 is T1 <T2, the content transmission control circuit 101 of the content transmission apparatus 100 determines the optimal transmission window 1022 size and transmission data 1023 from the T2 value measured by the content reception apparatus 200. Set to the size of.

  As described above, in the second embodiment, when transmitting / receiving content, the time from when the content transmitting apparatus 100 and the content receiving apparatus each transmit a specific packet and receive the reception confirmation response is measured. The content transmission apparatus 100 grasps the network traffic from the measurement result, and the content transmission apparatus 100 and the content reception apparatus 200 share the traffic measurement result, and the content transmission apparatus 100 determines the size of the transmission window 1022 based on the measurement result that is a bottleneck. The content receiving apparatus 200 adjusts the size of the reception window 2022 and the size of the reception data 2023.

  Thereby, the failure of the content transmission / reception processing due to the network traffic can be prevented. In addition to setting the size of the transmission / reception window and the size of transmission / reception data according to network traffic, IP packet priority is set using ToS (Type of Service) for IPv4 network and Flow Label for IPv6 network, for example. By doing so, it goes without saying that content can be transmitted and received without causing a failure.

  It is possible to provide a content transmission device and a content reception device capable of transmitting content in an optimum environment for each content when transmitting content with different bit rates using a wired or wireless LAN in the house.

1 is a first configuration diagram of a content transmission device and a content reception device according to an embodiment of the present invention. FIG. 1 is a block diagram of a wired LAN composed of a content transmission device and a content reception device according to an embodiment of the present invention. 1 is a detailed diagram of a content transmission device and a content reception device according to an embodiment of the present invention. The figure which shows an example of the size set to the network setting circuit and content control circuit by one Example of this invention. The figure which shows the procedure of the content transmission / reception process by one Example of this invention. The 2nd block diagram of the content transmission apparatus by one Example of this invention, and a content reception apparatus. The figure which shows an example of the size set to a network setting circuit and a content control circuit by the genre or category of the content by one Example of this invention. The figure which shows an example of the measurement procedure of the reception confirmation response time between the content transmission apparatus by one Example of this invention, and a content reception apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Content transmission apparatus 101 ... Content transmission control circuit 102 ... Network transmission processing circuit 1021 ... Transport layer (TCP / UDP)
1022 ... Transmission window 1023 ... Transmission data 1024 ... Network layer (IP)
DESCRIPTION OF SYMBOLS 103 ... Network transmission setting circuit 104 ... Transmission content control circuit 105 ... Data storage part 106 ... Timer circuit 200 ... Content reception apparatus 201 ... Content reception control circuit 202 ... Network reception processing circuit 2021 ... Transport layer (TCP / IP)
2022 ... Reception window 2023 ... Reception data 2024 ... Network layer (IP)
203 ... Network reception setting circuit 204 ... Received content control circuit 206 ... Timer circuit 300 ... Wired LAN
400… Hub 500… Router

Claims (6)

Network transmission processing means for transmitting data to the content receiving device via the network;
Content transmission control means for instructing a network transmission setting means and a transmission content control means on a transmission method of data to be transmitted to the content receiving device;
In response to an instruction from the content transmission control unit, the network transmission processing unit includes a first transmission method for determining a size of a transmission window that is a buffer that holds data that can be transmitted to the content receiving device at one time. Network transmission setting means for setting the first transmission method;
Data storage means for storing content to be transmitted to the content receiving device;
In response to an instruction from the content transmission control means, a second transmission method for determining the size of transmission data for obtaining data from the data storage means in one transmission process is provided, and the second transmission is sent to the network transmission processing circuit. Transmission content control means for writing data of a size determined by the method,
The content transmission control means determines the first transmission method and the second transmission method for each content to be transmitted to the content reception device via the network, and is at least one of the network transmission setting means and the transmission content control means, respectively. The content transmission apparatus is characterized by preventing deterioration of the image quality of the content to be transmitted and excessive consumption of resources used by the content transmission apparatus during content transmission.   The content to be transmitted to the content receiving device via the network is a Standard Definition (SD) video or a High Definition (HD) video, and the content transmission control means is determined by the first transmission method when transmitting the SD video. Decide to reduce the size of the transmission data determined by the window size and the second transmission method, and instruct at least one of the network transmission setting means and the transmission content control means, respectively. The control means determines that the size of the transmission window determined by the first transmission method and the size of the transmission data determined by the second transmission method are increased, and at least the network transmission setting means and the transmission content control means respectively. Content image to be sent by instructing either Deterioration and content transmission device content transmitting apparatus according to claim 1, wherein the preventing excessive consumption of resources to use when sending the content. Network reception processing means for receiving data from a content transmission device via a network;
Content reception control means for instructing a network reception setting means and a received content control means on a reception method of data received from the content transmission device;
In response to an instruction from the content reception control means, a first reception method is provided for determining a size of a reception window that is a buffer for holding data that can be received at one time from the content transmission device. Network reception setting means for setting one reception method;
Network reception setting means for setting in the network reception processing means;
In response to an instruction from the content reception control means, a second reception method for determining the size of received data for obtaining data from the network reception processing means in a single reception process is provided, and the received data is supplied to the content reception control means Receiving content control means,
The content reception control means determines the first reception method and the second reception method for each content received from the content transmission apparatus via the network, and is at least one of the network reception setting means and the received content control means, respectively. By instructing the content receiving apparatus, the content receiving apparatus is characterized by preventing deterioration of image quality of received content and excessive consumption of resources used by the content receiving apparatus when receiving content.   The content received from the content transmission device via the network is a Standard Definition (SD) video or a High Definition (HD) video, and the content reception control means is determined by the first reception method when receiving the SD video. Decide to reduce the size of the received data determined by the window size and the second reception method, and instruct at least one of the network reception control means and the reception content control means respectively, and receive the content when receiving HD video The control means determines that the size of the reception window determined by the first reception method and the size of the reception data determined by the second reception method are increased, and at least the network reception setting means and the received content control means respectively. An image of content to be received by instructing either one 4. The content receiving apparatus according to claim 3, wherein deterioration of quality and excessive consumption of resources used by the content receiving apparatus when receiving content are prevented. Network transmission processing means for transmitting data to the content receiving device via the network;
Content transmission control means for instructing a network transmission setting means and a transmission content control means on a transmission method of data to be transmitted to the content receiving device;
Network transmission setting means for receiving the instruction from the content transmission control means and setting the first transmission method in the network transmission processing means;
Data storage means for storing content to be transmitted from the data storage means to the data content receiving device according to the second transmission method in response to an instruction from the transmission control means;
Transmission content control means for acquiring content and supplying it to the network transmission processing means;
Timer means for transmitting a specific packet to the content receiving device and measuring a time until arrival of reception confirmation from the content receiving device;
The content transmission control means monitors the amount of data flowing through the network based on the value measured by the timer means, determines the first transmission method and the second transmission method according to the data amount, and transmits to the network transmission setting means and the transmission respectively. The network transmission setting means that instructed at least one of the content control means and received the instruction of the first transmission method reflects the instruction content in the transmission window size of the network transmission control means, and gives the instruction of the second transmission method. The received transmission content control means prevents the failure of the content transmission processing by reflecting the instruction content in the processing size of the content data to be transmitted to the content receiving device. Network reception processing means for receiving data from a content transmission device via a network;
Content reception control means for instructing a network reception setting means and a received content control means on a reception method of data received from the content transmission device;
Network reception setting means for receiving the instruction from the content reception control means and setting the first reception method in the network reception processing means;
Received content control means that receives an instruction from the content reception control means and acquires data from the network reception processing means according to the second reception method and supplies the data to the content reception control means;
Timer means for transmitting a specific packet to the content transmission device and measuring a time until arrival of reception confirmation from the content reception device;
The content reception control means monitors the amount of data flowing through the network from the value measured by the timer means, determines the first reception method and the second reception method according to the data amount, and sets the network reception setting means respectively. The network reception setting unit that receives the instruction of the first reception method reflects the instruction content in the reception window size of the network reception control unit, and receives the instruction of the second reception method. The received content control means that receives the instruction reflects the instruction content in the processing size of the content data received from the network reception processing means, thereby preventing the failure of the content receiving process.

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