JP2007195106A - Content data distribution system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content data distribution system which reduces a buffer capacity of a reproduction terminal and suppresses interruption and the quality change of a reproduced video image and music. <P>SOLUTION: In the content data distribution system, a server 1 divides the whole content data into preset partial content data Di. The server 1 distributes the initial partial content data D0 by redividing them into file data A0 and stream data B0 according to the lowest stream distribution speed RL of a network 102. In addition, the server 1 distributes the each piece of content data Di by redividing them into file data Ai and stream data Bi according to stream distribution estimated speed Riu at that time in the network 102. Here, each piece of file data Ai is individually set, respectively so that receiving buffers of the stream data Bi corresponding to each piece are in time for the reproduction of the stream data Bi. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a content data distribution system that distributes content data such as movies and music, and reproduces it on a reproduction terminal.

  Conventionally, there is a content distribution system that distributes content data such as movies and music over the Internet or the like. As an example of a content distribution system, there is one that first distributes all content data to a playback terminal. In this method, the playback terminal performs playback after buffering all the content data once. As another example of the content distribution system, there is so-called stream distribution in which content data is configured by an aggregate of packet data that is unit data, and packet data is sequentially distributed. In the case of stream distribution, the playback terminal sequentially receives and buffers packet data, and plays back the packet data when a predetermined buffer amount is reached.

  By the way, in the case of stream distribution, the buffer of the playback terminal may overflow or underflow due to the relationship between the data transmission speed and the playback speed, and the video and audio to be played are interrupted, and the image quality and sound quality change. May end up.

  For this reason, Patent Document 1 discloses a method for preventing underflow by adjusting the playback speed based on the buffer storage capacity of the playback terminal.

Patent Document 2 discloses a method for adjusting the transmission rate based on the buffer storage capacity of the playback terminal.
JP 2002-84339 A JP 2002-330180 A

  The invention described in Patent Document 1 described above can avoid the underflow of the buffer, but the image quality and sound quality of the reproduced video and the reproduced music change.

  The invention described in Patent Document 2 can adjust the data transmission rate, that is, only when the data transmission rate is always higher than the data reproduction rate, and prevents overflow of the buffer memory. Therefore, when the data transmission rate is substantially the same as the data reproduction rate or the data transmission rate is slower than the data reproduction rate, it is not possible to cope with it, and it is impossible to prevent the reproduction video and reproduction music from being interrupted.

  In the conventional method of buffering and reproducing all content data first, there is no interruption or change in image quality and sound quality, but if the content is large, the capacity of the buffer memory of the reproduction terminal must be increased. Don't be. Furthermore, if the content data is large and the data transmission rate is slow, the time until the buffer ends is very long.

  Accordingly, an object of the present invention is to provide a content data distribution system that can reduce the buffer capacity of a playback terminal and suppress interruptions and changes in quality of playback video and music.

  The content transmission means of the content data distribution system according to the present invention divides content data to be reproduced by a reproduction terminal into a plurality of partial content data each having a preset data length, and further delivers a stream corresponding to each partial content data Each partial content data is subdivided in the order of file partial content data and stream partial content data at an individual ratio for each partial content data based on the speed and the playback speed, and each file partial content data is sequentially transmitted through the first transmission path. In addition to file distribution, each stream partial content data is sequentially stream distributed through the second transmission path. Then, the playback terminal alternately time-series each file partial content data received via the first transmission path and each stream partial content data received via the second transmission path in order from the file partial content data. It is characterized by playing in.

  In this configuration, content data is divided by partial content data having a preset data length, and each partial content data is subdivided into file partial content data and stream partial content data according to the stream distribution speed at the time of distribution. It is.

  In this configuration, the content transmission unit divides content data of which the total data amount is known, such as a movie and music reproduced by a reproduction terminal, into a plurality of partial content data arranged in time series. These partial content data have a preset data length. The content transmission means further divides each partial content data into file partial content data and stream partial content data. At this time, each partial content data is divided by being arranged into file partial content data on the front side and stream partial content data on the rear side.

  Further, the content transmission means has a function of observing the stream delivery speed, that is, the transmission speed of the second transmission path for performing stream delivery, and observes the stream delivery speed when each stream partial content data is delivered. The content transmission means determines a data ratio between the file partial content data and the stream partial content data in the next (immediately) partial content data based on the obtained stream delivery speed and content data playback speed, and based on this data ratio Divide the corresponding partial content data. At this time, the content transmitting means can make the reproduction time based on the reproduction speed of the partial content data composed of the file partial content data and the stream partial content data longer than the distribution time based on the distribution speed of the corresponding stream partial content data. The data length of the file partial content data is set so that the data length is as short as possible.

  Then, the content transmission means transmits the file partial content data simultaneously formed via the first transmission path before the stream partial content data formed by this division. Note that the first partial content data is divided into file partial content data and stream partial content data in accordance with a preset data ratio.

  Each time the playback terminal receives each piece of file partial content data, it temporarily stores it. In addition, each time the playback terminal receives each stream partial content data, the playback terminal performs playback while buffering. When reproducing each piece of stream partial content data, the reproduction terminal reads and reproduces the file partial content data divided from the corresponding partial content data before reproducing the stream partial content data.

  As a result, even if the transmission speed of the second transmission path, that is, the stream delivery speed is slower than the content playback speed, the stream delivery time is as much as the playback time of the file part content data to be played back. There is room. Then, due to this margin, the stream distribution is not caught up with the stream reproduction, and changes or interruptions in the quality of the reproduced video or reproduced audio are prevented. Furthermore, since the ratio of the file partial content data changes according to the situation at each point of stream distribution, the file partial content data is not used more than necessary.

  Further, the content transmission means of the content data distribution system of the present invention detects the minimum stream distribution speed of the second transmission path, and based on the minimum stream distribution speed, the data of the file partial content data of the first partial content data It is characterized by setting the length.

  In this configuration, the content transmission means sets the division ratio of the first partial content data based on the lowest stream delivery speed of the second transmission path. Here, the minimum stream delivery speed is given by, for example, the minimum transmission speed defined in the second transmission path. As a result, the data length of the file partial content data is set so that the stream delivery time margin can be surely obtained even when the actual stream delivery is started.

  Further, the content transmission means of the content data distribution system of the present invention sets the data length of the file partial content data in advance, each file partial content data in which the data length is set constant, and the data of the file partial content data Content data to be played back on a playback terminal using a plurality of pieces of partial content data including a length, a stream delivery speed corresponding to each partial content data, and each stream partial content data whose data length is individually set based on the playback speed. It is divided into time series, and each file partial content data is sequentially distributed via the first transmission path, and each stream partial content data is sequentially distributed via the second transmission path. Then, the playback terminal alternately plays each file partial content data received via the first transmission path and each stream partial content data received via the second transmission path in order from the file partial content data. It is characterized by playing in series.

  In this configuration, when content data is divided by partial content data, the data length of the file partial content data is set in advance in the file partial content data and the stream partial content data constituting the partial content data and distributed. The data length of the stream partial content data, that is, the data length of the partial content data is set according to the stream delivery speed at the time.

  In this configuration, the content transmission means sequentially divides the content data reproduced by the reproduction terminal into a plurality of partial content data arranged in time series. These partial content data are composed of further divided file partial content data and stream partial content data, and the data capacity of the file partial content data is preset. At this time, each partial content data is divided into file partial content data on the front side and stream partial content data on the rear side.

  The content transmission means has a function of observing the stream delivery speed, that is, the transmission speed of the second transmission path for performing stream delivery, and observes the stream delivery speed when delivering each partial content data. The content transmission means determines the data ratio between the file partial content data and the stream partial content data in the next partial content data based on the obtained stream distribution speed and the reproduction speed of the content data, and the data ratio corresponds to this data ratio. Set the data length of the partial content data. At this time, the content transmitting means can make the reproduction time based on the reproduction speed of the partial content data composed of the file partial content data and the stream partial content data longer than the distribution time based on the distribution speed of the corresponding stream partial content data. The data length of the stream partial content data, that is, the data length of the partial content data is set so that the data length is as short as possible.

  Then, the content transmitting means transmits the file partial content data formed with the preset data length via the first transmission path before the stream partial content data formed by this division. For the first partial content data, the data length of the stream partial content data (partial content data) is set according to a preset data ratio.

  The playback terminal receives and temporarily stores each file partial content data. Also, the playback terminal receives each stream partial content data and plays it back while buffering. Here, at the time of reproduction of the stream partial content data, the reproduction terminal reads and reproduces the file partial content data divided from the corresponding partial content data before reproducing the stream partial content data.

  As a result, even if the stream delivery speed, that is, the transmission speed of the second transmission path is slower than the content playback speed, the stream delivery time is as much as the playback time of the file part content data to be played back. There is room. Then, due to this margin, the stream distribution is not caught up with the stream reproduction, and changes or interruptions in the quality of the reproduced video or reproduced audio are prevented. Furthermore, since the ratio of the file partial content data changes according to the situation at each point of stream distribution, the file partial content data is not used more than necessary. In addition, since the data length (data capacity) of the file partial content data is constant, relatively stable data distribution is possible.

  Further, the content transmission means of the content data distribution system of the present invention detects the minimum stream distribution speed of the second transmission path, and based on the minimum stream distribution speed, the data length of the stream partial content of the first partial content data It is characterized by setting.

  In this configuration, the content transmission means sets the data length of the first partial content data based on the lowest stream delivery speed of the second transmission path. Here, the minimum stream delivery speed is given by, for example, the minimum transmission speed defined in the second transmission path. Thus, even when actual stream distribution is started, the stream distribution is set so as to ensure a time margin for stream distribution based on the data length of the file partial content data.

  Further, the content transmission means of the content data distribution system of the present invention divides the content data to be reproduced on the reproduction terminal into a plurality of stream partial content data each having a preset data length, and sequentially distributes the stream in time series. At the same time, the interpolated content data to be inserted into the content data is file-distributed before stream distribution. When the playback terminal receives the interpolated content data and then sequentially receives and plays the stream partial content data, the playback terminal uses the stream partial content data based on the stream delivery speed and playback speed corresponding to each stream partial content data. The interpolated data length is calculated separately, and the corresponding interpolated content data is selected and reproduced based on the interpolated data length.

  In this configuration, content data is divided only by stream partial content data, and interpolated content data to be inserted between the stream partial content data is selected at each insertion time point according to the stream delivery speed at the time of delivery. .

  In this configuration, the content transmission means divides the content data reproduced by the reproduction terminal into a plurality of stream partial content data arranged in time series. The stream partial content data has a preset data length. Further, the content transmission means holds interpolated content data such as CMs having different data lengths, and distributes the interpolated content data in a file prior to stream distribution.

  The playback terminal receives and temporarily stores the interpolated content data. Further, the playback terminal has a function of observing the transmission speed of the second transmission path for performing stream distribution, and observes the transmission speed when each piece of stream partial content data is distributed.

  When the stream distribution is executed, the playback terminal detects the transmission speed of the second transmission path, and detects the data length (interpolation data length) to be inserted at the boundary of the stream partial content data immediately after. The playback terminal selects optimal interpolation content data based on the detected data length, and reads and plays back the corresponding interpolation content data continuously after the playback of the stream partial content data currently being played back. The reproduction terminal, after reproducing the interpolated content data, reproduces the next stream partial content data obtained by the time margin generated by reproducing the interpolated content data. At the start of stream reproduction, first, the interpolated content data set in advance is reproduced, and then the first stream partial content data is reproduced.

  As a result, even if the stream delivery speed, that is, the transmission speed of the second transmission path is slower than the content playback speed, a time margin for stream delivery can be obtained by the playback time of the interpolated content data. Then, due to this margin, the stream distribution is not caught up with the stream reproduction, and changes or interruptions in the quality of the reproduced video or reproduced audio are prevented. At this time, since the data length of the interpolated content data, that is, the reproduction time is set from the stream delivery speed at the time when each interpolated content data is inserted, the content data can be reproduced without reproducing the interpolated content data longer than necessary. can do.

  In addition, the playback terminal of the content data distribution system of the present invention is characterized in that it detects the minimum stream distribution speed of the second transmission path and selects the first interpolated content data based on the minimum stream distribution speed.

  In this configuration, the playback terminal sets the data length of the first interpolated content data based on the lowest stream delivery speed of the second transmission path. Here, the minimum stream delivery speed is given by, for example, the minimum transmission speed defined in the second transmission path. Thus, even when actual stream distribution is started, the stream distribution is set so as to ensure a time margin for stream distribution based on the data length of the interpolated content data.

  According to the present invention, partial content data to be file-distributed or interpolated content data and partial content data to be stream-distributed are used, and the data ratio of partial content data to be file-distributed or interpolated content data to partial content data to be stream-distributed is Set while adjusting sequentially according to the delivery speed. Thereby, it is possible to compensate for transmission delay of stream distribution and to prevent discontinuity and quality change of reproduced video and reproduced audio. Furthermore, when dividing partial content data into file partial content data and stream partial content data, use a stream delivery transmission path that is cheaper to use than a high-speed file delivery transmission path as much as possible. Can do. As a result, it is possible to reliably provide a user with a certain level of reproduced video and reproduced audio at a low cost.

The content data distribution system according to the first embodiment will be described with reference to FIGS.
FIG. 1 is a block diagram showing the configuration of the content data distribution system of this embodiment.
2 and 3 are sequence diagrams of the content data distribution system of this embodiment.
FIG. 4 is a flowchart showing the processing flow of the server 1 of this embodiment.
FIG. 5 is a flowchart showing the processing flow of the playback terminal 2 of this embodiment.
FIG. 6 is a diagram showing a content data dividing method and a time relationship between content data distribution, reception, and reproduction. In FIG. 6, the data D (i), A (i), and B (i) are represented as Di, Ai, and Bi, respectively.

First, the configuration of the content data distribution system of this embodiment will be described with reference to FIG.
The content data distribution system of this embodiment includes a server 1 and a playback terminal 2 that are wirelessly connected via a network 101 and a network 102.

  The server 1 includes a content storage device 10, a control unit 11, a packet generation unit 12, a transmission / reception module 13, and communication antennas 14A and 14B.

  The control unit 11 performs various processing controls on each unit of the server 1. Further, upon receiving a connection request from the playback terminal 2, the control unit 11 divides the corresponding content data into a plurality of partial content data having a preset data length.

  The content storage device 10 stores various content data such as video and music.

  The packet generator 12 converts the content data read from the content storage device 10 into packet data that is unit data constituting the content data. Then, the packet generation unit 12 generates file data and stream data composed of a predetermined number of packets using the generated packet data. Here, the file data is a file data obtained by converting a predetermined number of continuous packet data into a predetermined file format. Further, the stream data indicates a plurality of continuous packet data groups in a preset section, and is not particularly converted into another file format.

  Then, the control unit 11 gives an instruction to divide the entire content data into partial content data having a preset data length, as shown in FIG. 6, based on a method described later. Further, the control unit 11 detects the stream delivery speed of each partial content data, calculates a division ratio of the corresponding partial content data from the detected stream delivery speed, and converts the partial content data to file data according to the division ratio. And stream data are instructed.

  The packet generator 12 divides the content data into partial content data according to this instruction. Further, the packet generation unit 12 divides each partial content data so that the first side of the data becomes file data and the rear side becomes stream data at a division ratio designated for each. Thereby, the divided content data has a configuration in which file data and stream data appear alternately. That is, the content data is file data, stream data,..., File data, stream data in order from the top of the data.

  The transmission / reception module 13 is connected to the communication antennas 14A and 14B, and performs transmission / reception with respect to the networks 101 and 102 having different communication environments. Here, in the present embodiment, the network 101 is a high-speed and stable network but a high cost. On the other hand, the network 102 is a low-cost network whose communication environment is likely to change.

  The transmission / reception module 13 transmits the file data input from the packet generator 12 from the network 101 via the communication antenna 14A. On the other hand, the transmission / reception module 13 transmits stream data input from the packet generation unit 12 from the network 102 via the communication antenna 14B.

  The playback terminal 2 includes a CPU 21, a file memory 22, a buffer memory 23, a transmission / reception module 24, a playback unit 25, a playback unit 26, and communication antennas 27A and 27B. The playback terminal 2 is, for example, a mobile terminal such as a mobile personal computer, a PDA, or a mobile phone that plays back video data and audio data.

  The CPU 21 performs various processing controls on each part of the playback terminal 2. Further, the CPU 21 gives the file data read from the file memory 22 to the reproduction unit 25. The file memory 22 is a memory for temporarily storing file data. The buffer memory 23 is a memory for buffering stream data.

  The transmission / reception module 24 is connected to the communication antennas 27A and 27B, and performs transmission / reception with respect to the networks 101 and 102 having different communication environments. Further, the transmission / reception module 24 provides file data to the file memory 22 and stream data to the buffer memory 23 in accordance with an instruction from the CPU 21.

  The reproduction unit 25 reproduces the file data given from the CPU 21 and reproduces the stream data given from the buffer memory 23. At this time, the reproducing unit 25 reproduces the file data and the stream data at a preset constant reproduction speed so as to restore the original content data.

  The reproducer 26 includes a display such as a liquid crystal panel, a speaker system, and the like, and displays and emits a video signal and an audio signal reproduced by the reproducing unit 25.

  Next, the processing sequence of the content data distribution system will be described more specifically with reference to FIGS.

  The playback terminal 2 accepts an operation input by the user (S201), and makes a connection request including a request for introducing a desired content to the server 1 that distributes video and audio content (S202). At this time, the playback terminal 2 may transmit the connection request data via any of the networks 101 and 102.

  The server 1 receives the connection request data (S101), performs initial setting of content distribution processing (S102), and transmits connection permission data based on the connection request data to the reproduction terminal 2 (S103).

  The playback terminal 2 receives the connection permission data (S203) and performs a connection process with the server 1 (S204, S104).

  Next, when the user inputs a reproduction operation to the reproduction terminal 2, the reproduction terminal 2 accepts the reproduction operation (S205) and transmits reproduction request data (S206). At this time, the playback terminal 2 transmits playback request data via the network 102.

  When the server 1 receives the reproduction request data (S105), the server 1 sets the divided distribution and transmits the divided distribution execution instruction to the reproduction terminal 2 (S106). When the playback terminal 2 receives the split distribution execution instruction (S207), the playback terminal 2 performs split distribution setting.

  When the divided distribution is determined, the server 1 reads the content data selected at the time of the above connection request from the content storage device 10 and time-divides it into partial content data having a preset data length (S107). For example, if the data length of the entire content data is D and it is set to be divided into N, the data length of each partial content data is set to D / N, and the content data is divided into N in time series To do.

Next, the server 1 calculates the minimum stream delivery rate (bit rate) RL of the network 102 from the minimum transmission rate compensated by the network 102 (S108). The server 1 calculates the minimum data length satisfying the expression (1) using the data length of the initial partial content data D (0) and the minimum stream delivery speed (bit rate) RL set as described above. Thus, the data length of the initial file data A (0) is set (S109).
A ₍₀₎ > (1- (RL / r)) · D ₍₀₎ − (1)
In this equation, A ₍₀₎ indicates the data length of the initial file data, and D ₍₀₎ indicates the data length of the initial partial content data. Further, r represents the reproduction speed (bit rate) of content data in the reproduction terminal 2.

  When the server 1 generates the initial file data A (0), it sends it to the playback terminal 2 via the network 101 (S110).

  The playback terminal 2 receives the initial file data A (0) and temporarily stores it in the file memory 22 (S208 → S209 → S210). When reception of the initial file data A (0) is completed, the playback terminal 2 executes playback start processing (S211), and plays back the initial file data A (0) (S212). The trigger signal for starting reproduction is transmitted to the server 1.

  When detecting the reproduction start trigger signal, the server 1 generates initial stream data B (0) and sequentially delivers the stream via the network 102 (S111).

  When the playback terminal 2 sequentially receives the initial stream data B (0) (S214), the playback terminal 2 sequentially temporarily stores it in the buffer memory 23 (S215). The playback terminal 2 continues to receive and buffer the initial stream data B (0) when the initial file data A (0) is being played back, but when the playback of the initial file data A (0) is completed (S216), Subsequently, the initial stream data B (0) is stream-reproduced in order from the buffered head data (S217).

By the way, the server 1 detects the stream delivery speed (bit rate) R0 of the network 102 during the stream delivery of the initial stream data B (0) (see FIG. 6C). At this time, the server 1 detects the stream delivery rate R0 by setting a time point before a predetermined time from the time when the stream delivery of the initial stream data B (0) ends based on the calculated initial stream delivery rate RL. Then, the server 1 estimates the stream delivery speed R1u of the stream data B (1) of the next partial content data D (1) from the detected stream delivery speed R0 (S112 → S113). Then, while the playback terminal 2 is playing back the partial content data D (0), the server 11 uses the estimated stream distribution speed (bit rate) R1u and the data length of the partial content data D (1) to obtain an equation. The minimum data length satisfying (2) is calculated and set to the data length of the file data A (1) (S114).
A ₍₁₎ > (1- (R1u / r)). D ₍₁₎ -(2)
This formula is
A _(i) > (1- (Riu / r)) · D _(i) -(3)
I = 1, and the same applies to the subsequent partial content data D (i) (i = 2,...).

  When the server 1 generates the file data A (1), it sends it to the playback terminal 2 via the network 101 (S115). This transmission timing is performed at a timing when transmission / reception of the file data A (1) is completed by the time when the playback terminal 2 finishes playback of the partial content data D (0).

  The playback terminal 2 receives the file data A (1) and temporarily stores it in the file memory 22 (S219 → S209 → S210). When the reception and storage of the file data A (1) is completed, the playback terminal 2 detects whether or not the playback of the initial stream data B (0) has ended (S220).

  When the playback terminal 2 detects the end of playback of the initial stream data B (0), the playback terminal 2 starts playback of the file data A (1) (S213). This reproduction trigger signal is transmitted to the server 1. If the reproduction of the initial stream data B (0) has not been completed at the time of detection, the reproduction terminal 2 continues to receive, buffer, and reproduce the initial stream data B (0).

  When the server 1 detects the reproduction trigger signal of the file data A (1), the server 1 generates the stream data B (1) and sequentially delivers the stream via the network 102 (S116).

  When the playback terminal 2 sequentially receives the stream data B (1) (S214), the playback terminal 2 sequentially temporarily stores it in the buffer memory 23 (S215). The playback terminal 2 continues to receive and buffer the stream data B (1) when the file data A (1) is being played back, but when the playback of the file data A (1) ends (S216), the stream data continues. B (1) is stream-reproduced in order from the buffered head data (S217).

  After that, such content data transmission / reception processing is repeatedly performed while setting a different division ratio for each partial content data until the final partial content data is divided, transmitted / received, and reproduced. When the distribution of all the partial content data ends, the server 1 executes a distribution end process (S118 → S119). In addition, the playback terminal 2 executes playback end processing (S218 → S222).

  By using such a configuration and processing method, even when the content data delivery speed is lower than the playback speed, the transmission delay of the stream delivery is compensated, and the playback video and playback audio are not interrupted and the quality is prevented from changing. can do. Furthermore, by dividing the partial content data into file data and stream data, and setting the division ratio according to the stream delivery speed, the delivery on the transmission path for high-speed and expensive file delivery is suppressed, and the use cost is low. Stream transmission route can be used as much as possible. As a result, it is possible to reliably provide a user with a certain level of reproduced video and reproduced audio at a low cost.

  In the above description, the example in which the partial content data is divided so as to have the same data length is shown. However, the present invention is not limited to this, and the data length of each partial content data varies depending on the content data. It may be divided into

Next, a content data distribution system according to the second embodiment will be described with reference to FIGS.
7 and 8 are sequence diagrams of the content data distribution system of this embodiment.
FIG. 9 is a flowchart showing a processing flow of the server 1 of the present embodiment.
FIG. 10 is a diagram illustrating a content data dividing method and a time relationship between content data distribution, reception, and reproduction. In FIG. 10, the data D (i), A (i), and B (i) are expressed as Di, Ai, and Bi, respectively.

The content data distribution system of the present embodiment has the same configuration as that of the first embodiment, and only the content data dividing process is different, and the description of the same configuration and processing location is omitted.
When receiving a connection request from the playback terminal 2, the control unit 11 gives the packet generation unit 12 an instruction to sequentially extract partial content data from designated content data based on a method described later. Here, each partial content data is divided so that the top side of the data becomes file data and the back side becomes stream data. The data length of the file data of each partial content data is set in advance, and each stream data is appropriately set based on the stream delivery speed (bit rate) at that time and the data length of the preset file data. Is done. Thereby, the data length of each partial content data D is also set.

  In accordance with an instruction from the control unit 11, the packet generation unit 12 cuts out the partial content data with the data length set for each in chronological order, and further divides the cut out partial content data into file data and stream data .

  Next, the processing sequence of the content data distribution system of this embodiment will be described more specifically. Note that the processing of the playback terminal 2 is not different from that of the first embodiment, and a description thereof will be omitted.

  The server 1 receives the connection request data (S301), initializes the content distribution process (S302), and transmits connection permission data based on the connection request data to the playback terminal 2 (S303). Then, the server 1 performs a connection process with the playback terminal 2 (S304). Upon receiving the reproduction request data (S305), the server 1 sets the divided distribution and transmits an execution instruction for the divided distribution to the reproduction terminal 2 (S306).

  When the divided distribution is determined, the server 1 reads the content data selected at the time of the above connection request from the content storage device 10.

Next, the server 1 detects the minimum stream delivery rate (bit rate) RL of the network 102 from the minimum transmission rate compensated by the network 102 (S307). The server 1 calculates the maximum data length that satisfies the equation (4) using the data length of the initial file data A (0) and the minimum stream delivery speed (bit rate) RL in which the data length is set in advance. Then, the data length of the initial partial content data D (0) is set (S308).
D ₍₀₎ <(r / (r−RL)) · A ₍₀₎ − (4)
In this equation, A ₍₀₎ indicates the data length of the initial file data, and D ₍₀₎ indicates the data length of the initial partial content data. Further, r represents the reproduction speed (bit rate) of content data in the reproduction terminal 2.

  When the server 1 generates the initial file data A (0), the server 1 transmits it to the playback terminal 2 via the network 101 (S309).

  When detecting the reproduction start trigger signal, the server 1 generates initial stream data B (0) and sequentially delivers the stream via the network 102 (S310).

Further, the server 1 detects the stream delivery speed (bit rate) R0 of the network 102 during the stream delivery of the initial stream data B (0) (see FIG. 10C). At this time, the server 1 detects the stream delivery rate R0 by setting a time point before a predetermined time from the time when the stream delivery of the initial stream data B (0) ends based on the calculated initial stream delivery rate RL. Then, the server 1 estimates the stream delivery speed R1u of the stream data B (1) of the next partial content data D (1) from the detected stream delivery speed R0 (S311 → S312). Then, the server 11 uses the stream distribution speed (bit rate) R1u calculated and the data length of the file data A (1) while the reproduction terminal 2 reproduces the partial content data D (0), and uses the equation ( The maximum data length satisfying 5) is calculated and set to the data length of the partial content data D (1) (S313).
D ₍₁₎ <(r / (r-R1u)) · A ₍₁₎ -(5)
This formula is
D _(i) <(r / (r-Riu)). A _(i) -(6)
I = 1, and the same applies to the subsequent partial content data D (i) (i = 2,...).

  When the server 1 generates the file data A (1), it transmits it to the playback terminal 2 via the network 101 (S314). This transmission timing is performed at a timing when transmission / reception of the file data A (1) is completed by the time when the playback terminal 2 finishes playback of the partial content data D (0).

  When the server 1 detects the reproduction trigger signal of the file data A (1), the server 1 generates the stream data B (1) and sequentially delivers the stream via the network 102 (S315).

  By repeatedly performing such processing, partial content data cut out from the content data and having different data capacities according to the stream distribution speed at that time are sequentially distributed (S316 → S317 → S312).

  Then, when the distribution of all the partial content data is completed, the server 1 executes a distribution end process (S317 → S318).

  By performing such a configuration and processing, it is possible to prevent the playback video and playback audio from being interrupted and the quality from being changed as in the above-described embodiment. Furthermore, by dividing the partial content data into file data with a constant data length and stream data with a variable data length, the use of a high-speed and expensive file delivery transmission path is limited to a certain amount, and the usage cost is low. Stream transmission route can be used as much as possible. As a result, it is possible to provide the user with more reliably reproduced video and reproduced audio of a certain quality while suppressing the cost to some extent.

Next, a content data distribution system according to a third embodiment will be described with reference to FIGS.
FIG. 11 is a block diagram showing the configuration of the content data distribution system of this embodiment.
FIG. 12 is a sequence diagram of the content data distribution system of this embodiment.
FIG. 13 is a flowchart showing the processing flow of the server 1 of this embodiment.
FIG. 14 is a flowchart showing a processing flow of the playback terminal 2 of the present embodiment.
FIG. 15 is a diagram for explaining a method of dividing content data, and a diagram showing a time relationship between distribution, reception, and reproduction of content data.

  In the configuration of the content data distribution system of this embodiment shown in FIG. 11, the server device 1 includes a digital broadcast signal generation unit 15, and the content data storage device 10A stores the content such as video and music. And a content storage device 10B for storing interpolated content such as CMs. Since other configurations are the same, description thereof is omitted.

  The digital broadcast signal generation unit 15 generates a digital broadcast signal such as a soccer broadcast or a motor sports relay by a known method in accordance with an instruction from the control unit 11 and supplies the digital broadcast signal to the packet generation unit 12.

  The content storage device 10 </ b> A stores the main content selected by the user via the playback terminal 2, such as video and music, and the main content data is read to the packet generation unit 12 in accordance with an instruction from the control unit 11.

  The content storage device 10B stores interpolated content made up of various main contents stored in the content storage device 10A and CMs according to the field of digital broadcast programs, and even if the same type of interpolated content is stored. A plurality of interpolated contents having different data amounts, that is, different reproduction times are stored. The interpolated content is read out to the packet generator 12 in accordance with an instruction from the controller 11.

Next, the processing sequence of the content data distribution system according to the present embodiment will be described more specifically with reference to FIGS. In the following description, a case where content stored in advance in the content storage device 10A is reproduced will be described.
The playback terminal 2 receives an operation input by the user (S601), and makes a connection request including a request for introducing a desired content to the server 1 including the content storage device 10A in which video and audio content is stored (S602). At this time, the playback terminal 2 may transmit the connection request data via any of the networks 101 and 102.

  The server 1 receives the connection request data (S501), initializes the content distribution process (S502), and transmits connection permission data based on the connection request data to the playback terminal 2 (S503).

  The playback terminal 2 receives the connection permission data (S603) and performs a connection process with the server 1 (S604, S504).

  The server 1 selects an appropriate interpolated content from various types of interpolated content stored in the content storage device 10B based on the content field selected by the connection request. For example, if a video of a classical concert is selected, interpolation content (CM) such as a musical instrument or a CD is selected (S505). Further, for example, when a content of a soccer game is selected by digital broadcasting, an interpolation content (CM) for soccer equipment or an interpolation content (CM) related to a sponsor of a soccer team is selected. As shown in FIG. 15A, the interpolated content includes a plurality of interpolated content data having different data lengths, that is, different reproduction times, and the server 1 stores all of the same type of interpolated content having different data lengths. The data for transmission is selected and generated (S506). The generated plurality of interpolated content data I1 to I4 is transmitted to the playback terminal 2 via the network 101 (S507).

  The playback terminal 2 sequentially receives the interpolation content data I1 to I4 (S605) and temporarily stores them in the file memory 22 (S606).

  Next, when the user inputs a playback operation to the playback terminal 2, the playback terminal 2 accepts the playback operation (S607) and transmits playback request data (S608). Any network may be used at this time, but the reproduction request data may be transmitted through the network 101 because the reproduction request data is small and the reproduction request data is important as a trigger signal for starting reproduction.

  Next, the server 1 receives the reproduction request data (S508), divides the main content requested to be reproduced in advance and divides it into data lengths, and obtains partial content data D (i) (i = 1, 2). ,... Are sequentially generated (S509). When the server 1 is ready for stream distribution, the server 1 transmits stream distribution start control data via the network 102 (S510). At this time, the stream distribution start control data includes the data capacity of each partial content data.

  When receiving the stream delivery start control data from the server 1, the playback terminal 2 detects the lowest stream delivery rate RL of the network 102 from the lowest transmission rate compensated by the network 102 (S609 → S610 → S611).

The playback terminal 2 uses the data length of the initial stream data D (0) and the minimum stream delivery speed (bit rate) RL given from the server 1 to calculate the maximum data length that satisfies the equation (7). The initial interpolation content data length C (0) is set (S613).
C ₍₀₎ <((r−RL) / RL) · D ₍₀₎ − (7)
In this equation, D ₍₀₎ indicates the data length of the stream data (partial content data), and C ₍₀₎ indicates the initial interpolation content data length. Further, r represents the reproduction speed (bit rate) of content data in the reproduction terminal 2.

  Then, the playback terminal 2 selects the interpolated content data I (I (4) in the example of FIG. 15) optimum for the calculated initial interpolated content data length C (0) (S614), and the playback start timing (S615 → S617).

  The server 1 acquires the reproduction start timing of the reproduction terminal 2, generates stream data D (0) (S511), and sequentially distributes it via the network 102 (S512). When the stream distribution is started, the server 1 continuously performs stream distribution while sequentially generating stream data D (1), D (2),... As shown in FIG.

  The playback device 2 continues to receive and buffer the stream data D (0) while playing back the interpolated content data I (4) (S630). When the playback of the interpolated content data I (4) ends, the stream data D Playback of (0) is performed (S618).

  Next, the playback terminal 2 detects the end time of the stream data D (0) currently being played back. Then, the playback terminal 2 detects the stream delivery rate R1 of the network 102 at a timing before the end time and when receiving and buffering (S630) new stream data D (1) (S619). → S620 → S610 → S612).

The playback terminal 2 calculates the maximum data length that satisfies Equation (8) using the detected stream delivery rate R1 and the next stream data D (1) during playback of the stream data D (0). Thus, the interpolation content data length C (1) is set (S613).
C ₍₁₎ <((r−R1) / R1) · D ₍₁₎ − (8)
This formula is
C _(i) <((r-Ri) / Ri) .D _(i) -(9)
I = 1, and the same applies to the subsequent partial content data D (i) (i = 2,...).

  The playback terminal 2 selects the interpolated content data I (2) that is optimal for the calculated interpolated content data length C (1) (S614). When the playback terminal 2 selects the interpolated content data I (2), the playback terminal 2 continues to play back the interpolated content data I (2) when it detects the end of playback of the stream data D (0) (S616 → S617). When the playback of the interpolated content data I (2) is completed, the playback terminal 2 performs stream playback of the stream data D (1) (S618).

  The reproduction of the interpolated content data I (i) and the stream data D (i) is sequentially repeated as shown in FIG. 10D, and when the content end is detected, the server 1 and the reproduction terminal 2 Performs end processing (S513, S621).

  By performing such a configuration and processing, it is possible to reproduce the content while preventing the reproduction video and the reproduction audio from being interrupted and changing the quality as in the above-described embodiment. Furthermore, it is not necessary to perform processing for dividing the content into file data and stream data, and a server of a conventional stream distribution system can be used.

  Further, by using the processing method of the present embodiment, it is possible to shorten the interpolated content to be inserted into the content as much as possible.

  Furthermore, by matching the interpolated content with the field of the main content, it is possible to allow the viewer to view without giving a sense of incongruity between the main content and the interpolated content. Further, if the interpolated content is an advertising medium such as a commercial, it is possible to effectively view the commercial for viewers interested in the content.

  In the present embodiment, the case where the main content and the interpolated content are stored in one server has been described. However, a system including the main content server and a plurality of interpolated content servers may be formed. good. In this case, the playback terminal 2 selects a related interpolated content server from the selected main content field. Then, the interpolated content data may be acquired from the selected interpolated content server.

  In this embodiment, the initial interpolation content data is set based on the lowest stream distribution speed RL. However, more optimal initial interpolation is performed by transmitting / receiving the reproduction request data through the network 102 and detecting the distribution speed. Content data can be set.

  Further, in the present embodiment, as shown in FIG. 15, an example in which all content data is reproduced while interpolating content data is inserted has been described. In this method, all of the content data is reproduced, but for real-time content such as digital broadcasting, the delay time from reception to reproduction becomes longer, so the method shown in FIG. 16 may be used.

  FIG. 16 is a diagram showing a time relationship between distribution, reception, and reproduction of content data by another method.

  In the method shown in FIG. 16, initial interpolation content data is preliminarily obtained as short as possible interpolation content data (I (0) in the example of FIG. 16) based on the time τ0 required for reception, buffering, and reproduction of stream data. Set and play. As for stream reproduction, the reproduction is sequentially performed while receiving and buffering the stream data D (i), and when the buffer memory 23 underflows, new interpolation content data is selected and reproduced. Is. For example, in the example of FIG. 16, when the reproduction of the stream data D0 catches up with the reception / buffering of the stream data D0 and the buffer memory 23 underflows, the reproduction terminal 2 starts the stream data D0 from that point in time. The delay time τ1 until the reception / buffering end timing is detected. Note that the delay time τ1 is calculated from τ1 = D () based on the unreproduced portion D (0) n of the stream data D (0) and the stream delivery speed R1 detected immediately before the interruption timing of the stream data D (0). 0) Calculated by n / R1.

  The playback terminal 2 adds the delay time τ1 and the time τ0, and sets the interpolation content data length C1 to be newly inserted according to the equation (10).

C ₍₁₎ > r · (D ₍₀₎ n / R1 + τ0) − (10)
This formula is
C _(i) > r · (D _(i−1) n / Ri + τ0) − (11)
I = 1, and the same applies to the subsequent partial content data D (i) (i = 2,...).

  The playback terminal 2 selects the interpolated content data I (2) that is optimal for the calculated interpolated content data length C (1). When the reproduction terminal 2 selects the interpolation content data I (2), the reproduction terminal 2 reproduces the interpolation content data I (2) in accordance with the interruption timing. When the reproduction terminal 2 finishes reproducing the interpolated content data I (2), the reproduction terminal 2 performs stream reproduction of the stream data D (1). Such processing is repeated until the end of the content data (real-time content).

  By using such a processing method, the difference (delay) between the distribution time of the content data and the reproduction time of the content data can be reduced, and the time difference during real-time content distribution can be reduced.

It is a block diagram which shows the structure of the content data delivery system of 1st Embodiment. It is a sequence diagram (the first half) of the content data delivery system of 1st Embodiment. It is a sequence diagram (latter half) of the content data delivery system of 1st Embodiment. It is a flowchart which shows the processing flow of the server 1 of 1st Embodiment. It is a flowchart which shows the processing flow of the reproducing | regenerating terminal 2 of 1st Embodiment. It is a figure explaining the division | segmentation method of the content data of 1st Embodiment, and a figure which shows the time relationship of delivery, reception, and reproduction | regeneration of content data. It is a sequence diagram (the first half) of the content data delivery system of 2nd Embodiment. It is a sequence diagram (second half) of the content data delivery system of 2nd Embodiment. It is a flowchart which shows the processing flow of the server 1 of 2nd Embodiment. It is a figure explaining the division | segmentation method of the content data of 2nd Embodiment, and a figure which shows the time relationship of delivery, reception, and reproduction | regeneration of content data. It is a block diagram which shows the structure of the content data delivery system of 3rd Embodiment. It is a sequence diagram of the content data delivery system of 3rd Embodiment. It is a flowchart which shows the processing flow of the server 1 of 3rd Embodiment. It is a flowchart which shows the processing flow of the reproducing | regenerating terminal 2 of 3rd Embodiment. It is a figure explaining the division | segmentation method of the content data of 3rd Embodiment, and a figure which shows the time relationship of delivery, reception, and reproduction | regeneration of content data. It is a figure which shows the time relationship of the delivery of other content data of 3rd Embodiment, reception, and reproduction | regeneration.

Explanation of symbols

1-server 10, 10A, 10B-content storage device, 11-control unit, 12-packet generation unit, 13-transmission / reception module, 14A, 14B-antenna, 15-digital broadcast signal generation unit, 2-reproduction terminal, 21 CPU, 22-file memory, 23-buffer memory, 24-transmission / reception module, 25-playback unit, 26-playback unit

Claims (6)

Dividing content data to be reproduced on the reproduction terminal into a plurality of partial content data each having a preset data length,
Furthermore, each partial content data is subdivided in the order of file partial content data and stream partial content data in an individual ratio for each partial content data based on the stream delivery speed and playback speed corresponding to each partial content data,
Content transmitting means for sequentially distributing each file partial content data through a first transmission path and sequentially distributing each stream partial content data through a second transmission path;
Reproduction in which each file partial content data received via the first transmission path and each stream partial content data received via the second transmission path are alternately reproduced in time series in order from the file partial content data. A terminal,
A content data distribution system comprising: The content transmission means includes
2. The content data distribution system according to claim 1, wherein the minimum stream distribution speed of the second transmission path is detected, and the data length of the file partial content data of the first partial content data is set based on the minimum stream distribution speed. . Set the data length of the file part content data in advance,
The data length is individually set based on each file partial content data in which the data length is set constant, the data length of the file partial content data, the stream delivery speed corresponding to each partial content data, and the playback speed. The content data to be played back on the playback terminal is divided into time series by a plurality of partial content data composed of each stream partial content data,
Content transmitting means for sequentially distributing each file partial content data through a first transmission path and sequentially distributing each stream partial content data through a second transmission path;
Reproduction in which each file partial content data received via the first transmission path and each stream partial content data received via the second transmission path are alternately reproduced in time series in order from the file partial content data. A terminal,
A content data distribution system comprising: The content transmission means includes
The content data distribution system according to claim 3, wherein the minimum stream distribution speed of the second transmission path is detected, and the data length of the stream partial content of the first partial content data is set based on the minimum stream distribution speed. The content data to be played back on the playback terminal is divided into a plurality of stream partial content data each having a preset data length and sequentially streamed in time series, and the interpolated content data to be inserted into the content data is streamed. Content sending means for delivering files before,
After receiving the interpolated content data, when sequentially receiving and reproducing the stream partial content data, the interpolation data length between the stream partial content data based on the stream delivery speed and the playback speed corresponding to each stream partial content data Are calculated individually,
A playback terminal that selects and plays back the corresponding interpolated content data based on the interpolation data length;
A content data distribution system comprising: The playback terminal
6. The content data distribution system according to claim 5, wherein the lowest stream distribution speed of the second transmission path is detected, and the first interpolated content data is selected based on the minimum stream distribution speed.

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