JP2008141483A - Tree type distribution system, node device, information processing program, and information distribution method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tree type distribution system which performs streaming reproduction even when a plurality of pieces of distribution information with different delay times are distributed. <P>SOLUTION: In the tree type distribution system, nodes are connected like a tree using a distribution device as the highest order device, and first distribution information and second distribution information with longer delay time for outputting distribution information in the nodes are transferred from a high order node to a low order node. In the system, the distribution device is a means for starting distribution of the second distribution information before termination of distribution of the first distribution information, when the second distribution information is distributed following the first distribution information, and the node device is a means for, when the first or second distribution information is received, storing the first distribution information and the second distribution information and sequentially reproducing the first or second distribution information, and it detects timing for switching reproduction processing from the first or second distribution information under reproduction to the first or second distribution information which is to be reproduced next and when the timing is detected, starts reproduction processing of the first or second distribution information which is to be reproduced next. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a tree-type distribution system formed by participation of a plurality of node devices with the distribution device as the highest level, and in particular, a plurality of delay times required until distribution information is output in each node device. The present invention relates to a technical field of a tree-type distribution system in which distribution information is distributed.

  In a tree-type distribution system using ALM (Application Layer Multicast) technology, in order to prevent smooth playback processing of content (distribution information) in a node device (viewing terminal) due to a network communication failure or the like, In general, data streamed from a node device (or broadcast device) is temporarily buffered, and reproduction is started after a reference data amount necessary for reproduction is accumulated.

On the other hand, Patent Document 1 discloses a technique in which a plurality of streaming data having different delay times required until distribution information is output from each node device is distributed from the distribution device.
JP 2006-101101 A

  By the way, the “reference data amount” of buffering to be stored for smooth reproduction without delay depends on the bit rate that can be processed per unit time. In other words, playback processing is performed at a high bit rate in the case of a “high delay stream” with a large amount of delay, so that a reference data amount required for playback is relatively large and a “low delay stream” with a small delay amount is low. Since the reproduction process is performed at the bit rate, the reference data amount necessary for reproduction is smaller than that of the high delay stream. Thus, the reference data amount varies depending on the delay amount of each stream.

  Therefore, for example, when data streamed from an upstream node device (or broadcast device) is switched from a low delay stream to a high delay stream, the node device performs prebuffering of the reference data amount of the high delay stream. There is a problem that smooth reproduction is hindered, for example, it takes time and silence occurs between streams.

  Accordingly, an object of the present invention is to provide a tree-type distribution system that can smoothly perform streaming reproduction even when a plurality of pieces of distribution information having different delay times are received from a distribution apparatus.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices have a plurality of hierarchies with the distribution device as the highest level. And the first distribution information distributed from the distribution device and the distribution information distributed in the node device as compared to the first distribution information are output. And a second delivery information having a long delay time required until the second delivery information is sequentially transferred from the node device in the upper layer to the node device in the lower layer, wherein the delivery device includes: When the second distribution information is distributed following the first distribution information, the distribution unit starts distribution of the second distribution information in advance before the distribution of the first distribution information is completed. Said A receiving device that receives the first or second distribution information from the distribution device or another node device, and a storage device that stores the received first distribution information and the received second distribution information. Reproduction means for sequentially reproducing the first or second distribution information stored in the storage means, the first or second to be reproduced next from the first or second distribution information being reproduced. It has a detection means for detecting a switching timing for switching the reproduction process to distribution information, and when the detection timing is detected by the detection means, a reproduction process for the first or second distribution information to be reproduced next is started. A tree-type distribution system comprising: the reproduction means.

  According to this, even when a plurality of pieces of distribution information having different delay times required until the distribution information is output from the distribution device is distributed from the distribution device, each node device performs the reproduction process smoothly. Can be done.

  In order to solve the above-mentioned problem, the invention according to claim 2 is a tree type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices have a plurality of hierarchies with the distribution device as the highest level. And the first distribution information distributed from the distribution device and the distribution information distributed in the node device as compared to the first distribution information are output. The node device in the tree-type distribution system, wherein the second distribution information having a long delay time required until the second distribution information is sequentially transferred from the node device in the upper layer to the node device in the lower layer, The node device includes a receiving unit that receives the first or second distribution information from the distribution device or another node device, the received first distribution information, and the received second distribution. Storage means for storing information, and reproduction means for sequentially reproducing the first or second distribution information stored in the storage means, which should be reproduced next from the first or second distribution information being reproduced It has a detection means for detecting a switching timing for switching the reproduction process to the first or second distribution information, and when the switching timing is detected by the detection means, the first or second distribution to be reproduced next. And a playback device for starting a playback process of information.

  According to this, even when a plurality of pieces of distribution information having different delay times required until the distribution information is output from the distribution device is distributed from the distribution device, each node device performs the reproduction process smoothly. Can be done.

  In order to solve the above-mentioned problem, the invention according to claim 3 is the node device according to claim 2, wherein the receiving means is divided into a plurality of pieces of division information by the distribution device. Or the first distribution information including the first distribution information including the first reproduction switching instruction information for instructing to start the reproduction process of the first or second distribution information to be distributed next. When the second distribution information is received, the detecting means detects the switching timing when the one division information including the first reproduction switching instruction information is reproduced, and the reproducing means reproduces next. The node device is characterized by starting a reproduction process of the first or second distribution information.

  According to this, even when distribution information having different delay times is distributed, the switching timing can be reliably detected by each node device, and the reproduction process can be performed smoothly.

  In order to solve the above problem, an invention according to claim 4 is the node device according to claim 2, wherein the reception unit is divided into a plurality of pieces of division information by the distribution device. Or specific information for specifying one piece of division information constituting the first or second distribution information that has been received before the first or second distribution information, and second distribution information; The first or second distribution information having the one piece of division information including the second reproduction switching instruction information to instruct is received, and the detection unit reproduces the one piece of division information specified by the specific information Sometimes, the switching timing is detected, and the reproduction means starts reproduction processing of the first or second distribution information to be reproduced next.

  According to this, even when distribution information having different delay times is distributed, the switching timing can be reliably detected by each node device, and the reproduction process can be performed smoothly.

  In order to solve the above-mentioned problem, the invention according to claim 5 is the node device according to claim 3 or 4, wherein the receiving means includes the first reproduction switching instruction information of the first or second. After receiving the one piece of division information, the node device receives one piece of division information including the first or second reproduction switching instruction information at a predetermined interval.

  According to this, it is possible to reliably detect the switching timing by preventing the switch instruction information from being missed due to packet loss or the like.

  In order to solve the above-mentioned problem, the invention according to claim 6 is characterized in that the reproducing means is configured not to reproduce one piece of division information including the first or second reproduction switching instruction information. It is a node device.

  According to this, it is possible to reproduce only the distribution information to be reproduced.

  In order to solve the above problem, an invention according to claim 7 is an information processing program that causes a computer to function as the node device according to any one of claims 2 to 6.

  In order to solve the above-described problem, an invention according to claim 8 is a tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices have a plurality of hierarchies with the distribution device as the highest level. And the first distribution information distributed from the distribution device and the distribution information distributed in the node device as compared to the first distribution information are output. And a second delivery information having a long delay time required until the second delivery information is sequentially transferred from the node device in the upper layer to the node device in the lower layer, the information delivery method in the tree delivery system, When the distribution device distributes the second distribution information following the first distribution information, the distribution starts to distribute the second distribution information in advance before the distribution of the first distribution information ends. And a reception step in which the node device receives the first or second distribution information from the distribution device or another node device, and stores the received first distribution information and the received second distribution information. A storage step for storing in the means, and a reproduction step for sequentially reproducing the first or second distribution information stored in the storage means, which should be reproduced next from the first or second distribution information being reproduced. A detection step of detecting a switching timing for switching the reproduction process to the first or second distribution information, and when the switching timing is detected in the detection step, the first or second to be reproduced next; And a reproduction step of starting distribution information reproduction processing.

  According to the present invention, even when a plurality of pieces of distribution information having different delay times required until distribution information is output from the distribution device is distributed from the distribution device, each node device can smoothly perform reproduction processing. Can be performed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described with reference to the drawings. The embodiments described below are not limited to the embodiments described below, and the inventions such as the tree-type distribution system of the present invention are appropriately modified within the scope of the technical idea of the present invention. The

[1. Outline of tree-type distribution system]
First, the configuration and the like of the tree type distribution system S according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is an explanatory diagram illustrating an example of a connection mode of each device in the tree distribution system S according to the present embodiment, and FIG. 2 is a diagram illustrating an overview of the tree distribution system S according to the present embodiment.

  As shown in the lower frame 501 of FIG. 1, IX (Internet eXchange) 3, ISP (Internet Service Provider) 4, DSL (Digital Subscriber Line) line provider (device) 5, FTTH (Fiber To The Home) line A network (real-world network) 8 such as the Internet is constructed by a business operator (device) 6 and a communication line (for example, a telephone line or an optical cable) 7.

  The tree-type distribution system S is configured to include a plurality of node devices 32a, 32b, 32c,... 32m connected to each other via such a network 8, and becomes a peer-to-peer network system. ing. Each node device 32a, 32b, 32c... 32m is assigned a unique manufacturing number and IP (Internet Protocol) address as information indicating the node device. The serial number and the IP address are not duplicated among the plurality of node devices 32. In the following tree-type distribution system content distribution system tree-type distribution system tree-type description, when any one of the node devices 32a, 32b, 32c,. There is a case.

  This tree-type distribution system S constructs a tree-type distribution network using the existing network 8 by the broadcasting device 31 and each node device 32 as shown in the upper frame 500 of FIG. ing.

  In the tree-type distribution system S, a plurality of node devices 32a to 32m form a plurality of hierarchies with the broadcasting device 31 as the highest level, and are connected in a tree shape via a plurality of communication paths based on respective IP addresses. become. The broadcasting device 31 and the plurality of node devices 32a to 32m are connected to the Internet by the IX3, ISP4, DSL line operator (device) 5, FTTH line operator (device) 6, communication line 7, etc. The content data distributed by the broadcasting device 31 is sequentially transferred from the higher layer node devices 32a and 32b to the lower layer node devices 32c to 32m. That is, the node devices 32a to 32f are relayed and stream-distributed to the node devices 32c to 32m.

  It should be noted that the participation in the tree-type distribution system S is such that the node device 32 that newly desires to participate is connected to the broadcasting device 31 and each node device 32 (which node device is which node device (or broadcasting device 31). ) Is accessed as a connection destination introduction server (not shown) storing topology management information (topology database) as a candidate for a higher-level node device 32 to be connected to. By being informed of the device information (including the IP address) of the node device 32 that has already participated, it becomes possible to establish a connection through a new communication path with the node device 32 that has already participated. Yes.

  From the broadcasting device 31, for example, a relatively high-quality content such as video and music and a content such as a news broadcast that requires a real-time property although the quality is lower than such content are mixed and distributed. Is done. These content data are delivered by the broadcasting device 31 after being compressed and encoded by the high quality encoder, and the latter is lower than the high quality encoder by the low delay encoder whose delay time is shorter than that of the high quality encoder. Compression / encoding processing is performed at the compression rate, and streaming distribution is performed to each node device 32. In the following description, content distributed after being compressed and encoded by a high quality encoder is referred to as a “high delay stream” as an example of the second distribution information of the present invention, and is compressed and encoded by a low delay encoder. The content that is processed and distributed is referred to as a “low delay stream” as an example of the first distribution information of the present invention.

  When receiving the high delay stream and the low delay stream from the upstream node device 32 (or the broadcast device 31) via the communication paths 33a to 33m, the node devices 32a to 32m first temporarily buffer (pre-buffer) Buffering), and after accumulating the reference data amount necessary for reproduction, reproduction processing is sequentially performed on the data accumulated in the buffer. By the way, this reference data amount depends on the bit rate that can be processed per unit time. That is, in the case of a high-delay stream with high quality (in other words, with a large amount of delay), reproduction processing is performed at a high bit rate, so that the amount of reference data necessary for reproduction is relatively large and low delay with a small amount of delay. In the case of a stream, reproduction processing is performed at a low bit rate, so that the reference data amount necessary for reproduction is smaller than that of a high-delay stream.

  Each node device 32 grasps which data of the high-delay stream and the low-delay stream is received from the upstream node device 32 (or the broadcast device 31), and while reproducing the high-delay stream or the low-delay stream, When the reproduction switching timing is detected, the reproduction of the high delay stream or the low delay stream to be reproduced next is started.

  FIG. 3 is an explanatory diagram showing the reception, prebuffering, and reproduction output of the high delay stream and the low delay stream in the node device 32 in time series.

  The figure shows, for example, when a high-delay stream such as “Δ Hibiki Hour” is received from an upstream node device 32 (or broadcast device 31) after a low-delay stream such as “News”. This shows buffering and playback output. During playback and reception of a low-delay stream, the high-delay stream to be played next is received and the high-delay stream pre-buffering is performed, and the high-delay stream is played back. During reception, the low-delay stream to be reproduced next is received and the low-delay stream pre-buffering is performed. Each stream is distributed as packet data, which is an example of a plurality of pieces of division information, from the upstream node device 32 (or the broadcast device 31), but in the period “A” shown in the figure, the node device 32 receives packet data of both the low delay stream and the high delay stream in a mixed manner such as “low”, “high”, “low”, “high”, “high”, “low”,.

  The node device 32 stores the packet data of the low delay stream in the buffer during the pre-buffering periods Ba and Bc, and stores the packet data of the high delay stream in the buffer during the pre-buffering periods Bb and Bd. In particular, since the high-delay stream consumes more than the low-delay stream, it is preferable that the playback process is switched early and buffering is performed early (compared to when the low-delay stream switches the playback process). Thus, the reference data amount can be reliably accumulated at the time of reproduction, and smooth reproduction can be performed. The “reproduction processing” in the present embodiment includes pre-buffering, data decoding, and output from a speaker, a monitor, and the like.

The switching of the reproduction process is performed by the node device 32 receiving, reproducing, and detecting the switching instruction information. Specifically, there are the following two methods. For example, when switching playback from a low delay stream to a high delay stream,
(I) As a first technique, the node device 32 reproduces next by detecting the switching instruction information as the first reproduction switching instruction information in the present invention included in the low delay stream received before the high delay stream. Start pre-buffering of high delay streams.
(Ii) As a second method, the node device 32 detects the specific information included in the high delay stream and the prebuffer of the high delay stream by detecting the switching instruction information as the second reproduction switching instruction information in the present invention. Start the ring. The specific information is information for specifying one packet data constituting the low-delay stream that has been received before the high-delay stream including the specific information, and when the packet data specified thereby is reproduced and output, Pre-buffering of the high delay stream (that is, the high delay stream to be reproduced next) is started.

  Hereinafter, in the description of the data structure of content, switching of reproduction processing from a low delay stream to a high delay stream will be described in detail.

[1-1. Content data structure]
Hereinafter, the data structure of content distributed from the broadcasting station apparatus 31 will be described.

  FIG. 4A is a data structure diagram of content distributed from the broadcasting station apparatus 31.

The broadcast station apparatus 31 distributes the low delay stream and the high delay stream with different delay times to the downstream node apparatus 32. Each stream data is divided into a plurality of packets (packet data) as shown in FIG. 4 (B-1), and a header including a stream ID and a packet serial number is added to each packet. The stream ID specifies the delay amount of the stream. In the case of a low-delay stream, “01” is assigned as the stream ID. The packet serial number is a serial number assigned to a plurality of packets constituting one low-delay stream data in the order to be reproduced. For example, one low-delay stream data is divided into 100 packets. If it is, “001” to “100” are assigned as packet serial numbers.
(I) Switching of reproduction processing by the first technique Subsequently, switching of reproduction processing by the first technique will be described with reference to a data structure diagram of a low-delay stream including switching instruction information shown in FIG. explain.

  In the case of the first method, the switching instruction information is included in a low-delay stream whose next is a high-delay stream. Such low-delay stream data is divided into a plurality of packets (packet data) like other stream data, and a header is added to each of these packets. Some headers are composed of stream IDs and packet serial numbers, and some are composed of switching instruction information. The switching instruction information is for instructing the start of the reproduction processing of the high-delay stream to be reproduced next. The node apparatus 32 receives the switching instruction information from the upstream node apparatus 32 (or broadcasting apparatus 31) as a header. When the packet included in is reproduced, the reproduction processing of the high delay stream data to be reproduced next is started. In the case of the example shown in FIG. 4B-2, a packet having a packet sequence number “001” to “003” is added with a header composed of a stream ID and a packet sequence number, and the packet sequence number “ The “100” packet has a header composed of a stream ID, a packet serial number, and switching instruction information. Accordingly, in the node device 32, by reproducing the packet with the packet sequence number “100” including the switching instruction information in the header, the switching timing is detected, and the reproduction processing of the high delay stream data to be reproduced next is started.

  Thereby, for example, when a high-delay stream such as “Δ Hibiki Hour” is delivered after the low-delay stream such as “News” from the upstream node device 32 (or broadcast device 31), or IP phone Even if a high-delay stream such as a disc jockey's voice is delivered after a low-delay stream such as a listener's voice in Internet broadcasting using the system, a packet containing switching instruction information in the low-delay stream being played back Since the switching timing is detected by playing and the high delay stream to be played next is started, each node device 32 can smoothly play various contents with different delay times.

  In the above-described method, the switching instruction information is configured to be included in the header of the final packet that constitutes the low-delay stream that is the next high-delay stream, but not only the header of the final packet but also a plurality of packets at predetermined intervals. The header may include switching instruction information. In this way, by configuring the header of a plurality of packets to include switching instruction information, even if one packet is lost (packet loss) during communication, switching instruction information of other packets Based on the above, smooth playback can be performed by starting the playback processing of the high-delay stream to be played next without error.

  As an example of such a configuration, for example, as shown in FIG. 5 (B-3), dummy packets configured with switching instruction information (that is, not including content data) are included in the low-delay stream at predetermined intervals. It can also comprise.

Then, in the node device 32, when the dummy packet including the switching instruction information is reproduced from the upstream node device 32 (or the broadcasting device 31), the reproduction processing of the high delay stream data to be reproduced next is started. Even in this case, even if one dummy packet is lost during communication (packet loss), based on the switching instruction information of another dummy packet, the reproduction processing of the high-delay stream to be reproduced next Can be started without error and smooth reproduction can be performed.
(Ii) Switching of Reproduction Process by Second Method Next, switching of the reproduction process by the first method will be described with reference to FIG.

  6A is a data structure diagram of content distributed from the broadcasting station apparatus 31, and FIG. 6B-1 is a data structure diagram of each stream data. Since this is the same as FIG. 4 (A) and FIG. 4 (B-1) of “switching of reproduction processing”, description thereof is omitted here.

  In the case of the second method, the switching instruction information is included in the high delay stream to be reproduced next. Such a high-delay stream is divided into a plurality of packets (packet data) like other stream data, and a header is added to each of these packets. The header includes a stream ID and a packet serial number, and further includes identification information for specifying one packet constituting low-delay stream data that has been received before the high-delay stream, and switching instruction information. Some are configured. When the node device 32 reproduces the packet data constituting the received low-delay stream data specified by the specific information, the node device 32 performs a reproduction process of the high-delay stream (that is, the next high-delay stream to be reproduced). Start. In the case of the example shown in FIG. 6B-2, a packet having a packet serial number “002” to “004” is appended with a header composed of a stream ID and a packet serial number, and the head of the packet serial number “001”. The packet has a header composed of a stream ID, a packet serial number, specific information, and switching instruction information. This specifying information specifies the packet data of the packet serial number “015” of the low-delay stream that has been received previously. Therefore, in the node device 32, when the packet data of the packet sequence number “015” of the previously received low-delay stream is reproduced, the switching timing is detected and the high-delay stream (that is, the next high-reproduction stream to be reproduced) is detected. (Delay stream) playback processing is started.

  In the above-described method, the specific information and the switching instruction information are included in the header of the first packet constituting the high-delay stream. However, the specific information is not only included in the header of the first packet but also in the headers of a plurality of packets at a predetermined interval. And switching instruction information may be included. In this way, by including specific information and switching instruction information in the headers of a plurality of packets, even if one packet is lost (packet loss) during communication, Based on the specific information and the switching instruction information, the playback process of the high delay stream to be played next can be started without error and smooth playback can be performed.

  As an example of such a configuration, for example, as shown in FIG. 7B-3, a dummy packet configured with specific information and switching instruction information (that is, not including content data) is predetermined in a high-delay stream. It can also be configured to include at intervals.

  When the node device 32 reproduces the packet data of the received low-delay stream specified by the specification information included in the dummy packet from the upstream node device 32 (or the broadcast device 31), The reproduction process of the delayed stream (that is, the high delay stream to be reproduced next) is started. Also in this case, even when one dummy packet is lost during communication (packet loss), the high-delay stream to be reproduced next is based on the specific information of other dummy packets and the switching instruction information. The reproduction process can be started without error and smooth reproduction can be performed.

  As described above, the switching of the reproduction process from the low delay stream to the high delay stream has been described with reference to FIGS. 4 to 7. However, when the reproduction process is switched from the high delay stream to the low delay stream, the first and second processes described above are performed. Techniques can be used.

[2. Configuration of each device constituting the tree distribution system]
With reference to FIG.8 and FIG.9, the structure etc. of the node apparatus 32 and the broadcasting apparatus 31 which comprise the tree type delivery system S are demonstrated.

[2-1. Node device configuration]
First, the configuration and functions of the node device 32 will be described with reference to a schematic configuration example of the node device 32 shown in FIG. The configuration of each node device 32 is the same.

  As shown in FIG. 8, each node device 32 includes a CPU 11 having an arithmetic function, a high delay stream buffer for temporarily storing received high delay stream data, and a low delay for temporarily storing received low delay stream data. A ring buffer memory 121 including a stream buffer, an operating system 122, a stream control program 123, and a screen control program 124 for decoding (data expansion, decoding, etc.) encoded video data (video information) included in each stream data. , A topology management program 125, a music decoder 126 for decoding (data expansion, decoding, etc.) encoded audio data (audio information) included in the stream data, and a working RAM, R for storing various data and programs Main storage device 12 composed of M, etc., hard disk device 13 as a recording medium composed of HD for storing and storing (storing) various data, programs, etc., and peripherals such as hard disk device 13 and input unit Peripheral device control chip 14 that controls connection with the device and transmits information, video chip 15 that performs a predetermined drawing process on the decoded video data and the like and outputs it as a video signal, and output from the video chip 15 A built-in display 16 such as a CRT or a liquid crystal display for displaying an image based on the video signal, and the decoded audio data converted into an analog audio signal by D (Digital) / A (Analog) and then amplified by an amplifier. The sound source chip 17 to be output and the audio signal output from the sound source chip 17 as sound waves Receiving an input from the built-in speaker 18 and an external user input remote controller 23, etc., receiving an instruction from the user, and giving an instruction signal corresponding to the instruction to the CPU 11 as an infrared port (others) In addition, for example, a keyboard, a mouse, or an operation panel is possible) 19 and a network interface 21 for controlling communication of information between the node device 32 and the like via the router 24 and the like through the network 8. The CPU 11, the main storage device 12, the peripheral device control chip 14, the video chip 15, the sound source chip 17, and the network interface 21 are connected to each other via a system bus 22. The network interface 21 is connected to an external router 24 and the like via the network 8. The infrared port 19 receives an instruction signal from the user-input remote controller 23 and transmits the signal to the peripheral device control chip 14.

  The CPU 11 performs overall control of the entire node device 32 by executing various programs including the information processing program of the present invention stored in the main storage device 12 and the like. Participation channel selection processing and the like are performed in response to an instruction signal from the section. The node device 32 functions as a broadcasting device 31, a node device that transmits (transfers) information, a node device that receives information, and the like according to a program to be executed. The CPU 11 of the node device 32 functions as a receiving unit, a storing unit, a reproducing unit, and a detecting unit of the present invention.

[2-2. Configuration of broadcasting device]
Next, with reference to a schematic configuration example of the broadcast device 31 shown in FIG. 9, the configuration and function of the broadcast device 31 as the distribution device of the present invention will be described.

  As shown in FIG. 9, the broadcast apparatus 31 includes a CPU 311 having a calculation function, a high delay stream buffer for temporarily storing high delay stream data to be transmitted, and a low delay stream for temporarily storing low delay stream data to be transmitted. A ring buffer memory 3121 including a buffer, an operating system 3122, a stream control program 3123, a screen control program 3124 for decoding (data expansion, decoding, etc.) encoded video data (video information) included in the stream data, topology A management program 3125 and a music decoder 3126 for decoding (data expansion, decoding, etc.) encoded audio data (sound information) included in the stream data are provided, and a working RAM, various data and programs are recorded. A main storage device 312 composed of a ROM and the like, a hard disk device 313 composed of an HD for storing and storing (storing) broadcast content data (stream data), a program, and the like, a hard disk device 313 and an input A peripheral device control chip 314 that controls connection with peripheral devices such as video units and transmits information, a video chip 3151 that performs predetermined drawing processing on decoded video data and the like, and outputs the video signal, and the video A display 3161 such as a CRT or a liquid crystal display that displays an image based on the video signal output from the chip 3151, and the decoded audio data is converted into an analog audio signal by D (Digital) / A (Analog) and then this is amplified by an amplifier. A sound source chip 3152 to be amplified and output, and A speaker 3162 that outputs an audio signal output from the source chip 3152 as a sound wave, and a keyboard 3163 and a mouse 3164 as an input unit that receives an instruction from the user and provides an instruction signal corresponding to the instruction to the CPU 311 A network interface 317 for controlling communication of information between the node device 32 and the like via the router 319 and the like via the network 8, and a power source 320. The CPU 311, the main storage device 312, the peripheral device control chip 314, the video chip 3151, the sound source chip 3152 and the network interface 317 are connected to each other via a system bus 318. The network interface 317 is connected to an external router 319 or the like via the network 8.

  The CPU 311 performs overall control of the entire broadcasting device 31 by executing various programs stored in the main storage device 312 and the like, and according to an instruction signal from an input unit such as a keyboard 3163. Various processes are performed.

[3. Operation in Tree Distribution System of this Embodiment]
Next, the operation of each device in the tree-type distribution system S of the present embodiment will be described with reference to FIGS.

[3-1. Operation of broadcasting device]
First, with reference to FIG. 10, the operation of the broadcasting apparatus 31 of the present embodiment will be described. The broadcast device 31 controls the distribution timing so as to start distributing the distribution information to be transmitted next in advance when transmitting the distribution information having different delay times when sequentially distributing the streams. For example, when delivering a high delay stream following a low delay stream, delivery of the high delay stream is started before delivery of the low delay stream ends.

  When the CPU 311 of the broadcasting device 31 recognizes that the broadcasting device 31 has been turned on by the keyboard 3163, the mouse 3164, and the like, it starts the information processing shown in the flowchart of FIG. The following processing is executed based on the control of the CPU 311.

  When the process is started, the CPU 311 initializes various settings such as the program of the broadcasting device 31 (step S1), and determines whether it is the transmission timing of the high delay stream (step S2). If it is the transmission timing of the high-delay stream (step S2: Yes), the high-delay stream packet is transmitted (step S3), the process proceeds to step S6, and if it is not the transmission timing of the high-delay stream (step S2: No) ), It is determined whether it is the transmission timing of the dummy packet of the high delay stream (step S4).

  As a result of the determination, if it is the transmission timing of the dummy packet of the high delay stream (step S4: Yes), the dummy packet of the high delay stream is transmitted (step S5), and it is not the transmission timing of the dummy packet of the high delay stream In (Step S4: No), the process proceeds to Step S6.

  Next, it is determined whether it is the transmission timing of the low delay stream (step S6). If it is the transmission timing of the low-delay stream (step S6: Yes), the low-delay stream packet is transmitted (step S7), the process proceeds to step S10, and if it is not the transmission timing of the low-delay stream (step S6: No) ), It is determined whether or not it is the transmission timing of the dummy packet of the low delay stream (step S8).

  As a result of the determination, if it is the transmission timing of the dummy packet of the low delay stream (step S8: Yes), the dummy packet of the low delay stream is transmitted (step S9), and it is not the transmission timing of the dummy packet of the low delay stream In (Step S8: No), the process proceeds to Step S10.

  Then, it is determined whether or not the service as the broadcasting device 31 is to be ended by an input from the keyboard 3163 and the mouse 3164, an instruction via the network interface 317, or the like (step S10). When the content distribution service as the broadcasting device 31 is terminated (step S10: Yes), the processing is terminated, and when the content distribution service as the broadcasting device 31 is not terminated (step S10: No), step S1 is performed. Return to.

[3-2. Operation of node equipment]
Next, the operation of the node device 32 of this embodiment will be described with reference to FIGS.
(I) When switching reproduction processing by the first method First, the operation of the node device 32 when switching reproduction processing by the first method will be described.

  When the CPU 11 of the node device 32 recognizes that the power of the node device 32 is turned on by the user input remote controller 23 or the like, the CPU 11 starts the information processing shown in the flowchart of FIG. The following processing is executed based on the control of the CPU 11.

  When the processing is started, the CPU 11 initializes various settings such as the program of the node device 32, and subsequently determines whether or not a packet is received from the upstream node device 32 (or the broadcasting device 31) (step S1). S21). If a packet has not been received (step S21: No), the process proceeds to step S23. If a packet has been received (step S21: Yes), the packet is stored in the corresponding buffer (step S22). Specifically, the stream ID in the header of the received packet is confirmed to determine whether the packet is low-delay stream data or high-delay stream data. If the stream ID is “01”, the ring The low-delay stream data in the buffer memory 121 is stored in a low-delay stream buffer that temporarily accumulates. If the stream ID is “02”, the high-delay stream data in the ring buffer memory 121 is stored in a high-delay stream buffer that temporarily accumulates. When the packet is saved in the buffer, the header is removed before saving.

  Next, it is determined whether or not there is a packet in the high delay stream buffer (step S23). If there is a packet in the high delay stream buffer (step S23: Yes), it is determined whether or not the high delay stream can be reproduced. Judgment is made (step S24). As a result of the determination in step S24, if it is determined that the high-delay stream can be reproduced (step S24: Yes), it is determined whether or not the packet received in step S21 is a dummy packet (step S25). .

  If it is determined that the received packet is a dummy packet (step S25: Yes), the process proceeds to step S27. If the received packet is not a dummy packet (step S25: No), the received packet is reproduced. Since the packet constitutes stream data to be processed, the high-delay stream packet buffered in the high-delay stream buffer is reproduced (step S26).

  Subsequently, it is determined whether or not there is switching instruction information in the header of the packet received in step S21 (step S27). If there is no switching instruction information (step S27: No), the process proceeds to step S35 and switching is performed. If there is instruction information (step S27: Yes), the reproduction of the stream to be reproduced next is permitted (step S28), and the process proceeds to step S35.

  On the other hand, if it is determined in step S23 that there is no packet in the high-delay stream buffer (step S23: No), and if it is determined in step S24 that the high-delay stream is not reproducible (step In S24: No), the process proceeds to step S29, and it is determined whether or not there is a packet in the low delay stream buffer (step S29). As a result of the determination, if there is no packet in the low-delay stream buffer (step S29: No), the process proceeds to step S35. If there is a packet in the low-delay stream buffer (step S29: Yes), the low-delay stream is not It is determined whether or not reproduction is possible (step S30).

  As a result of the determination in step S30, when it is determined that the low-delay stream is not reproducible (step S30: No), the process proceeds to step S35, and when it is determined that the low-delay stream is reproducible (step S30). : Yes), it is then determined whether or not the packet received in step S21 is a dummy packet (step S31).

  If it is determined that the received packet is a dummy packet (step S31: Yes), the process proceeds to step S33. If the received packet is not a dummy packet (step S31: No), the received packet is reproduced. Since the packet constitutes stream data to be processed, the low-delay stream packet buffered in the low-delay stream buffer is reproduced (step S32).

  Then, it is determined whether or not there is switching instruction information in the header of the packet received in step S21 (step S33). If there is no switching instruction information (step S33: No), the process proceeds to step S35 and the switching instruction is issued. When there is information (step S33: Yes), the reproduction of the stream to be reproduced next is permitted (step S34), and the process proceeds to step S35.

  Subsequently, when the node device 32 is turned off or moved to another channel (another tree configured with the other broadcasting device as the highest level) or the like, the user selects to leave the system S. If it is determined whether or not separation is selected (step S35: Yes), the process ends. If separation is not selected (step S35: No), the process returns to step S21. .

(Ii) Case where Playback Process is Switched by Second Method Next, the operation of the node device 32 when the playback process is switched by the second method will be described.

  When the CPU 11 of the node device 32 recognizes that the power of the node device 32 is turned on by the user input remote controller 23 or the like, the CPU 11 starts the information processing shown in the flowchart of FIG. The following processing is executed based on the control of the CPU 11.

  When the process is started, the CPU 11 first initializes various settings such as a program of the node device 32, and then determines whether or not a packet is received from the upstream node device 32 (or the broadcast device 31). (Step S51). If a packet has not been received (step S51: No), the process proceeds to step S53. If a packet has been received (step S51: Yes), the packet is stored in the corresponding buffer (step S52). Specifically, the stream ID in the header of the received packet is confirmed to determine whether the packet is low-delay stream data or high-delay stream data. If the stream ID is “01”, the ring The low-delay stream data in the buffer memory 121 is stored in a low-delay stream buffer that temporarily accumulates. If the stream ID is “02”, the high-delay stream data in the ring buffer memory 121 is stored in a high-delay stream buffer that temporarily accumulates. When the packet is saved in the buffer, the header is removed before saving.

  Next, it is determined whether or not there is a packet in the high delay stream buffer (step S53). If there is a packet in the high delay stream buffer (step S53: Yes), the packet serial number of the received low delay stream is It is determined whether or not the packet serial number is specified by the specific information (step S54). That is, the low delay specified by the received packet serial number counter of the low delay stream data and the specific information included in the dummy packet received in the previous process (or the specific information included in the header of the packet of the high delay stream) The packet sequence number of the packet data of the stream is compared, and it is determined whether or not the received packet sequence number counter of the low delay stream data is equal to or greater than the packet sequence number of the packet data of the low delay stream specified by the specific information.

  As a result of the determination, if the packet sequence number of the received low-delay stream is equal to or greater than the packet sequence number specified in the specific information (step S54: Yes), it is determined whether or not the received packet is a dummy packet. Judgment is made (step S55).

  As a result of the determination, if the received packet is a dummy packet (step S55: Yes), the process proceeds to step S57.

  On the other hand, when the received packet is not a dummy packet (step S55: No), since the received packet is a packet constituting stream data to be reproduced, the high-delay stream packet buffered in the high-delay stream buffer is not received. Playback is performed (step S56), and the process proceeds to step S57.

  Subsequently, due to the reception of the packet in step S51, the corresponding received packet serial number is updated (step S57). That is, if the received packet is low-delay stream data, the reception packet sequence number counter of the low-delay stream data is updated to “1”. If the received packet is high-delay stream data, the received packet of the high-delay stream data The serial number counter is updated by “1”. The received packet serial number counter is performed by using, for example, a working RAM of the main storage device 12. Then, the process proceeds to step S63.

  On the other hand, when it is determined in step S53 that there is no packet in the high-delay stream buffer (step S53: No), and in step S54, the received packet sequence number of the low-delay stream is included in the specific information. If it is not equal to or more than the specified packet sequence number (step S54: No), the process proceeds to step S58, and it is determined whether or not there is a packet in the low-delay stream buffer (step S58).

  If there is a packet in the low-delay stream buffer as a result of the determination (step S58: Yes), it is determined whether or not the packet sequence number of the received high-delay stream is greater than or equal to the packet sequence number specified by the specific information. (Step S59). That is, the low delay specified by the received packet serial number counter of the high delay stream data and the specific information included in the dummy packet received in the previous process (or the specific information included in the header of the packet of the low delay stream) The packet sequence number of the packet data of the stream is compared, and it is determined whether or not the received packet sequence number counter of the low delay stream data is equal to or greater than the packet sequence number of the packet data of the low delay stream specified by the specific information.

  As a result of the determination, if the packet sequence number of the received high-delay stream is equal to or greater than the packet sequence number specified in the specific information (step S59: Yes), it is determined whether or not the received packet is a dummy packet. Judgment is made (step S60).

  As a result of the determination, if the received packet is a dummy packet (step S60: Yes), the process proceeds to step S62.

  On the other hand, when the received packet is not a dummy packet (step S60: No), since the received packet is a packet constituting stream data to be reproduced, the low-delay stream packet buffered in the low-delay stream buffer is not received. Playback is performed (step S61), and the process proceeds to step S62.

  Subsequently, the corresponding received packet sequence number is updated due to the reception of the packet in step S51 (step S62). That is, if the received packet is low-delay stream data, the reception packet sequence number counter of the low-delay stream data is updated to “1”. If the received packet is high-delay stream data, the received packet of the high-delay stream data The serial number counter is updated by “1”. Then, the process proceeds to step S63.

  On the other hand, when there is no packet in the low-delay stream buffer (step S58: No), or when the packet sequence number of the received high-delay stream is not greater than or equal to the packet sequence number specified in the specific information (step S59: No). Moves to step S63.

  Whether the node device 32 is turned off or moved to another channel (another tree configured with the other broadcasting device as the highest level), etc., so that the user has selected to leave the system S. It is determined whether or not (step S63), and when leaving is selected (step S63: Yes), the process is terminated, and when leaving is not selected (step S63: No), the process returns to step S51.

  As described above, in the present embodiment, in the tree-type distribution system in which a low delay stream and a high delay stream having different delay times are sequentially transferred to the node device 32, the broadcast device 31 follows the low delay stream. When delivering the delayed stream, the delivery of the high-delay stream is started before the delivery of the low-delay stream is completed, and the node device 32 receives from the upstream node device 32 or the broadcast device 31. When playing back the low-delay stream (or high-delay stream) while buffering, the playback process from the low-delay stream (or high-delay stream) being played back to the next high-delay stream (or low-delay stream) to be played back Detecting the switching timing for switching the high-delay stream (or low-delay stream) to be reproduced next ) Is started so that a low-delay stream and a high-delay stream having different delay times required for playback and output by the node device 32 from the broadcasting device 31 are distributed. Each node device 32 can perform a reproduction process smoothly.

  Further, when a high delay stream is reproduced following the low delay stream, a reproduction process of the high delay stream to be reproduced next is added to the header of any bucket (for example, the last packet) constituting the low delay stream. Is configured to include switching instruction information for instructing to start, and is configured to detect switching timing when a packet including the switching instruction information is received. Even so, the reproduction process can be performed smoothly. When a low-delay stream is reproduced following the high-delay stream, a low-delay stream reproduction process to be reproduced next is added to the header of any bucket (for example, the last packet) constituting the high-delay stream. The same effect can be obtained by including switching instruction information for instructing to start.

  Furthermore, as another method, when a high-delay stream is reproduced following a low-delay stream, specific information for identifying any bucket constituting the low-delay stream and reproduction of the high-delay stream to be reproduced next The switching instruction information for instructing to start processing is included in the header of a packet (for example, the first packet) constituting the high-delay stream, and the low-delay stream packet specified by the specific information is received. Since the switching timing is detected at this time, even if the next stream to be reproduced is a stream having a different delay time, the reproduction process can be performed smoothly. When a low-delay stream is reproduced following a high-delay stream, specific information for identifying any bucket that constitutes the high-delay stream and a process for reproducing the low-delay stream to be reproduced next are started. The same effect can be obtained if the switching instruction information to be instructed is configured to be included in the header of a packet (for example, the head packet) constituting the low-delay stream.

  In addition, if the above-described switching instruction information (and specific information) is included in the headers of a plurality of packets constituting a stream, even if an accident such as packet loss occurs, switching instruction information of other packets (And the specific information) can reliably start reproduction of the next stream to be reproduced. Furthermore, a dummy packet including the switching instruction information (and specific information) may be included in the stream at a predetermined interval.

  In addition, when the received packet is a dummy packet in the determination of steps S25, S31, S55, and S60 described above, the dummy packet stored in the buffer is not reproduced, but stored in the buffer. It may be determined whether or not the packet received before the process is a dummy packet, and if it is a dummy packet, it is not stored in the buffer.

  A program corresponding to each operation of the node device 32 and the broadcasting device 31 described above is recorded on an information recording medium such as a flexible disk or a hard disk, or is acquired and recorded via a network such as the Internet. By reading and executing with a microcomputer or the like, the microcomputer can function as the CPU 11 or the CPU 311 according to each embodiment.

It is a figure which shows an example of the connection aspect of each node apparatus in the tree type delivery system S which concerns on this embodiment. It is a figure explaining the outline | summary of the tree type delivery system S which concerns on this embodiment. It is the figure which showed the reception of the high delay stream and the low delay stream in the node apparatus 32, a pre-buffering process, and the reproduction output in time series. (A) is a data structure diagram of content distributed from the broadcasting station apparatus 31, (B-1) is a data structure diagram of stream data, and (B-2) is a low delay stream whose next is a high delay stream. FIG. (A) is a data structure diagram of content distributed from the broadcasting station apparatus 31, and (B-3) is a data structure diagram of a low-delay stream in which the next is a high-delay stream when a dummy packet is included. (A) is a data structure diagram of content distributed from the broadcasting station apparatus 31, (B-1) is a data structure diagram of stream data, and (B-2) is a high-delay stream in which the previous is a low-delay stream. FIG. (A) is a data structure diagram of content distributed from the broadcasting station apparatus 31, and (B-3) is a data structure diagram of a high delay stream, which is a low delay stream before, when dummy packets are included. 3 is a diagram illustrating a schematic configuration example of a node device 32. FIG. 2 is a diagram illustrating a schematic configuration example of a broadcasting device 31. FIG. 4 is a flowchart showing processing in the broadcasting device 31. It is a flowchart which shows the process in the node apparatus 32 in the case of switching a reproduction | regeneration process by a 1st method. It is a flowchart which shows the process in the node apparatus 32 in the case of switching reproduction | regeneration processing by a 2nd method.

Explanation of symbols

32 Node device 31 Broadcast device 8 Network 11 CPU
DESCRIPTION OF SYMBOLS 12 Main memory device 13 Hard disk device 14 Peripheral device control chip 15 Video chip 16 Built-in display 17 Sound source chip 18 Built-in speaker 19 Infrared port 21 Network interface 22 System bus 23 Remote control for user input 24 Router S Tree type distribution system

Claims (8)

A tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies with the distribution device as the highest level. The first distribution information distributed from the device and the second distribution information having a longer delay time before the distribution information distributed in the node device is output than the first distribution information A tree-type distribution system that is sequentially transferred from the node device in a hierarchy to the node device in a lower hierarchy,
The distribution device includes:
When the second distribution information is distributed following the first distribution information, the distribution unit starts distribution of the second distribution information in advance before the distribution of the first distribution information is completed.
The node device is
Receiving means for receiving the first or second distribution information from the distribution device or another node device;
Storage means for storing the received first distribution information and the received second distribution information;
Reproducing means for sequentially reproducing the first or second distribution information stored in the storage means, wherein the first or second distribution information to be reproduced next from the first or second distribution information being reproduced. Detecting means for detecting a switching timing for switching the reproduction process to, and when the switching timing is detected by the detecting means, the reproduction process of the first or second distribution information to be reproduced next is started. Reproduction means;
A tree-type distribution system characterized by comprising: A tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies with the distribution device as the highest level. The first distribution information distributed from the device and the second distribution information having a longer delay time before the distribution information distributed in the node device is output than the first distribution information The node device in the tree-type distribution system that is sequentially transferred from the node device in the hierarchy to the node device in the lower hierarchy,
The node device is
Receiving means for receiving the first or second distribution information from the distribution device or another node device;
Storage means for storing the received first distribution information and the received second distribution information;
Reproducing means for sequentially reproducing the first or second distribution information stored in the storage means, wherein the first or second distribution information to be reproduced next from the first or second distribution information being reproduced. Detecting means for detecting a switching timing for switching the reproduction process to, and when the switching timing is detected by the detecting means, the reproduction process of the first or second distribution information to be reproduced next is started. Reproduction means;
A node device comprising: The node device according to claim 2, wherein
The receiving means starts the reproduction process of the first or second distribution information which is the first or second distribution information divided into a plurality of pieces of division information by the distribution device and is distributed next. Receiving the first or second distribution information having one piece of the division information including the first reproduction switching instruction information to instruct;
The detecting means detects the switching timing when the one piece of division information including the first reproduction switching instruction information is reproduced, and the reproducing means performs the first or second distribution to be reproduced next. A node device which starts information reproduction processing. The node device according to claim 2, wherein
The receiving means is the first or second distribution information divided into a plurality of pieces of division information by the distribution device, and has been received before the first or second distribution information. Receiving the first or second distribution information having one piece of division information including identification information for specifying one piece of division information constituting two pieces of distribution information and second reproduction switching instruction information for instructing reproduction start;
The detection means detects the switching timing when the one piece of division information specified by the specific information is reproduced, and the reproduction means detects the first or second distribution information to be reproduced next. A node device which starts reproduction processing. The node device according to claim 3 or 4, wherein
The reception unit receives the one piece of division information including the first or second reproduction switching instruction information at a predetermined interval after receiving the one piece of division information including the first or second reproduction switching instruction information. A node device characterized by that. The node device according to claim 5, wherein
The node device is configured so that the reproduction means does not reproduce one piece of the division information including the first or second reproduction switching instruction information.   An information processing program for causing a computer to function as the node device according to any one of claims 2 to 6. A tree-type distribution system formed by participation of a plurality of node devices, wherein the plurality of node devices are connected in a tree shape via communication means while forming a plurality of hierarchies with the distribution device as the highest level. The first distribution information distributed from the device and the second distribution information having a longer delay time before the distribution information distributed in the node device is output than the first distribution information An information distribution method in a tree-type distribution system that is sequentially transferred from the node device in a hierarchy to the node device in a lower hierarchy,
When the distribution device distributes the second distribution information following the first distribution information, the distribution step of starting the distribution of the second distribution information before the distribution of the first distribution information is completed. When,
The node device is
A receiving step of receiving the first or second distribution information from the distribution device or another node device;
A storage step of storing the received first distribution information and the received second distribution information in a storage means;
The reproduction step of sequentially reproducing the first or second distribution information stored in the storage means, and the first or second distribution information to be reproduced next from the first or second distribution information being reproduced And a detection process for detecting a switching timing for switching the reproduction process to, and when the switching timing is detected in the detection process, a reproduction process for the first or second distribution information to be reproduced next is started. The regeneration step;
An information distribution method characterized by comprising:

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