JP2015056879A - Content distribution device, content distribution method and content distribution program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embed digital watermark data at a low cost.SOLUTION: A content distribution server generates a plurality of timings by using at least one of a content distribution date and time, a location, and identification information for identifying a user of the distribution destination. The content distribution server switches a bit rate of streaming data corresponding to the content by the generated timing and distributes the content to a terminal device that is a distribution destination such as a smart phone.

Description

  The present invention relates to a content distribution apparatus, a content distribution method, and a content distribution program.

  Digital contents such as videos and music are distributed to portable terminals such as smartphones via a network. In addition, when digital content is distributed by wireless distribution using radio waves or the like, the communication status is not stable, so the bit rate is dynamically changed and distributed. As a technique for preventing users from illegally dubbing and redistributing digital content to be distributed, there is known a technology for distributing digital watermark data embedded in digital content.

JP 2011-55286 A JP-A-10-336626

  However, in the above technique, after embedding digital watermark data, the bit rate is dynamically controlled depending on the condition of the line and the radio wave condition, so that the system becomes complicated and it is necessary to prevent redistribution and the like. Cost increases.

  The disclosed technology has been made in view of the above, and an object thereof is to provide a content distribution device, a content distribution method, and a content distribution program that can embed digital watermark data at low cost.

  In one aspect, a content distribution device disclosed in the present application includes a generation unit that generates a plurality of timings using at least one of date and time of content distribution, a location, and identification information for identifying a distribution destination user. The content distribution apparatus includes a distribution unit that distributes the content by switching a bit rate of stream data corresponding to the content at each timing generated by the generation unit.

  According to one aspect of the content distribution device, the content distribution method, and the content distribution program disclosed in the present application, it is possible to embed digital watermark data at a low cost.

FIG. 1 is a diagram illustrating an example of the overall configuration of a system according to the first embodiment. FIG. 2 is a functional block diagram illustrating a functional configuration of the content distribution server according to the first embodiment. FIG. 3 is a flowchart illustrating a flow of processing executed by the content distribution server according to the first embodiment. FIG. 4 is a diagram illustrating an example of generation of digital watermark data according to the first embodiment. FIG. 5 is a schematic diagram illustrating an example of generating stream data according to the first embodiment. FIG. 6 is a flowchart illustrating a flow of distribution processing for measuring quality at each switching timing according to the second embodiment. FIG. 7 is a diagram illustrating an example of streaming delivery according to the second embodiment. FIG. 8 is a flowchart illustrating the flow of a process for changing the stream ratio according to the third embodiment. FIG. 9 is a diagram illustrating a specific example 1 of ratio change according to the third embodiment. FIG. 10 is a diagram for explaining a specific example 2 of the ratio change according to the third embodiment. FIG. 11 is a diagram for explaining a specific example 3 of the ratio change according to the third embodiment. FIG. 12 is a diagram illustrating a hardware configuration example of the content distribution server.

  Hereinafter, embodiments of a content distribution apparatus, a content distribution method, and a content distribution program disclosed in the present application will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Each embodiment can be appropriately combined within a consistent range.

[overall structure]
FIG. 1 is a diagram illustrating an example of the overall configuration of a system according to the first embodiment. As shown in FIG. 1, this system includes a plurality of terminal devices 1, a license server 5, and a content distribution server 10. In addition, the number of each apparatus shown here is an illustration to the last, and is not limited to this.

  The terminal device 1 is a terminal device such as a mobile phone, a smartphone, or a notebook computer, and corresponds to various portable terminals, for example. The terminal device 1 receives content from the content distribution server 10 by stream distribution using wireless communication.

  The license server 5 is a server device that issues a content license to the terminal device 1. For example, the license server 5 issues a license that identifies the type of content, the date and time of content distribution, the location of the content distribution server 10 that distributes the content, the user of the distribution destination, and the like.

  The content distribution server 10 is a server device that streams content to the terminal device 1. For example, the content distribution server 10 holds a plurality of bit rate stream data, and executes stream distribution at a bit rate corresponding to the communication quality of wireless communication with the terminal device 1.

  Specifically, the content distribution server 10 generates a plurality of timings using at least one of the date / time, location, and distribution destination user for distributing the content. Then, the content distribution server 10 switches the bit rate of the stream data corresponding to the content at each generated timing, and distributes the content to the terminal device 1.

  In this way, the content distribution server 10 can identify the receiving user and the reception date and time based on the bit rate switching location of the distributed data by switching the bit rate at different timings for each user and date and time during stream distribution. Therefore, the content distribution server 10 can easily realize a digital watermark and can embed the digital watermark data at a low cost.

[Content distribution server configuration]
Next, the functional configuration of the content distribution server shown in FIG. 1 will be described. The terminal device 1 has the same functional configuration as that of a general smartphone, and the license server 5 has the same functional configuration as that of a general server device, and thus detailed description thereof is omitted here.

  FIG. 2 is a functional block diagram illustrating a functional configuration of the content distribution server according to the first embodiment. As shown in FIG. 2, the content distribution server 10 includes a communication control unit 11, a storage unit 12, and a control unit 15.

  The communication control unit 11 is a communication interface that performs wireless communication and wired communication, and is a wireless communication circuit including, for example, a network interface card and an antenna. For example, the communication control unit 11 receives a content license from the license server 5 via wired communication or wireless communication. Further, the communication control unit 11 distributes the content stream data to the terminal device 1 using wireless communication.

  The storage unit 12 is a storage device that stores programs and data executed by the control unit 15, and is a memory or a hard disk, for example. The storage unit 12 includes a license DB 13 and a stream DB 14.

  The license DB 13 is a database that stores license information of content received from the license server 5. Specifically, the license DB 13 stores a license for identifying a content type, a content distribution date and time, a location of the content distribution server 10 that distributes the content, a distribution destination user, and the like. Which content is distributed to which user can be identified by the information stored here.

  The stream DB 14 stores a plurality of stream data having different bit rates in association with each content. For example, for the content A, the stream DB 14 stores “S1” that is high-quality stream data, “S2” that is medium-quality stream data, and “S3” that is low-quality stream data.

  The stream DB 14 stores stream data obtained by inverting flag bits included in stream data for each quality of stream data. For example, the stream DB 14 stores “S1 ′” obtained by inverting the flag bit for “S1” that is high-quality stream data. The flag bit is provided at a position where the influence on the content is small.

  The control unit 15 is a processing unit that controls the entire content distribution server 10, and is a processor such as a CPU (Central Processing Unit), for example. The control unit 15 includes a quality monitoring unit 16, a license reception unit 17, a timing generation unit 18, a stream generation unit 19, and a distribution unit 20. Each processing unit included in the control unit 15 is an example of a process executed by the processor and an electronic circuit included in the processor.

  The quality monitoring unit 16 is a processing unit that monitors the wireless quality between the distribution destination terminal device 1 and the content distribution server 10. The quality monitoring unit 16 performs quality monitoring using various known techniques. For example, the quality monitoring unit 16 measures the wireless quality by measuring the time for transmitting and receiving packets to and from the terminal device 1. Also, the quality monitoring unit 16 can measure the wireless quality by acquiring the reception time and reproduction start time of the stream from the terminal device 1 and comparing it with the transmission time of the stream.

  The license receiving unit 17 is a processing unit that receives license information of content to be distributed. For example, the license receiving unit 17 receives license information from the license server 5 including the date and time when the content is distributed, the distribution location, the user ID of the distribution destination, and the IP (Internet Protocol) address of the distribution destination. The license information is used to specify which content is distributed to which user at which date and time.

  The timing generation unit 18 is a processing unit that generates a plurality of timings using the license information received by the license reception unit 17. Specifically, the timing generation unit 18 uses at least one of the date and time when the content included in the license information is distributed, the distribution location, the distribution destination user ID, and the distribution destination IP address in the timing information column. replace.

  For example, the timing generation unit 18 converts license information expressed in a decimal number sequence into a hexadecimal number, and converts the information converted into the hexadecimal number into a binary number. Subsequently, the timing generation unit 18 re-divides the binary data into three bits. Thereafter, the timing generation unit 18 converts the data divided by 3 bits into decimal numbers, and then converts the data into ternary numbers again to generate digital watermark data.

  On the other hand, the timing generation unit 18 generates a virtual clock whose reference time is 0 at the start of stream distribution or timing generation, and assigns ascending clock numbers 1, 2, 3,. To do. Here, the clock number represents an elapsed time from the reference time. Subsequently, the timing generation unit 18 generates a plurality of groups, with four clock numbers such that the clock number / 4 is the same integer value as one group. For example, the timing generation unit 18 sets the clock numbers “0, 1, 2, 3” as one group, the clock numbers “4, 5, 6, 7” as one group, and the clock numbers “8, 9, 10, 11”. Are classified into one group.

  Then, the timing generation unit 18 associates one group for each digit of the digital watermark data expressed in ternary two digits. For example, when the digital watermark data is “10, 20, 20,...”, The timing generation unit 18 associates “1” of “10” with the clock group “0, 1, 2, 3”, “0” of “10” is associated with clock groups “4, 5, 6, 7”. Similarly, the timing generation unit 18 associates “2” of “20” with the clock group “8, 9, 10, 11”, “0” of “20”, and clock groups “12, 13, 14, 15 ”. Thereafter, the timing generation unit 18 outputs the associated result to the stream generation unit 19.

  Note that the stream generation unit 19 specifies the ternary sequence “2” when a predetermined number of clock groups have elapsed from the reference time in order to specify what time the reference time is when the virtual clock is initialized. To the subsequent clock group. For example, when the clock group is classified into 30 groups, “2” is associated with the first group and the 24th to 30th groups as one digit of the ternary string. Therefore, it can be seen that when three or more ternary string “2” continues, it is a delimiter of stream data.

  The stream generation unit 19 is a processing unit that generates stream data in which the bit rate is switched at each timing generated by the timing generation unit 18. Specifically, the stream generation unit 19 associates the clock number of each clock group with a ternary number, and switches the stream data at the timing of one digit of the associated ternary string for each clock group.

  For example, the stream generation unit 19 associates “0, 1, 2” that is one digit of the ternary number in order from the smallest number in the clock group. Specifically, the stream generation unit 19 sequentially associates “0, 1, 2” with the clock numbers “0, 1, 2, 3”, and the clock numbers “4, 5, 6, 7”. Sequentially correspond to “0, 1, 2”. The stream generation unit 19 switches the stream data at the timing of the clock number “1” because the clock number “0, 1, 2, 3” is associated with one digit “1” in the ternary example. . Further, the stream generation unit 19 switches the bit rate at the timing of the clock number “4” because the clock number “4, 5, 6, 7” is associated with one digit “0” in the ternary example. .

  In this way, when generating the stream data corresponding to the content to be distributed, the stream generation unit 19 generates the stream data with the bit rate switched at the time indicated by one ternary digit in each clock group.

  Here, the stream generation unit 19 can switch to a bit rate corresponding to the quality of wireless communication when starting generation of stream data. For example, assume that the quality monitoring unit 16 determines that the quality has deteriorated. In that case, the stream generation unit 19 uses high-quality S1 data until the first switching timing, switches to medium-quality S2 data at the switching timing, and switches to high-quality S1 data at the next switching timing. Thus, the stream generation unit 19 can generate one stream data using stream data having different qualities.

  Further, it is assumed that the quality monitoring unit 16 determines that the quality is the same. In this case, the stream generation unit 19 uses the stream data obtained by inverting the flag bit included in the stream data before switching, because there is no change in the communication quality to the delivery destination at the timing of switching to the stream. Can be generated. That is, the stream data is switched at the timing of the ternary sequence, but the stream data of the same quality is combined only by inverting the flag bit.

  The distribution unit 20 is a processing unit that distributes the stream data generated by the stream generation unit 19 to the terminal device 1 as stream data corresponding to the content to be distributed. For example, the distribution unit 20 distributes the stream data generated by the stream generation unit 19 to the terminal device 1 specified by an administrator, a license, or the like.

[Process flow]
Next, an example of the flow of processing executed by the content distribution server will be described. Note that the processing described here is an example, and the order of processing and the like can be appropriately changed within a range where there is no contradiction.

  FIG. 3 is a flowchart illustrating a flow of processing executed by the content distribution server according to the first embodiment. As shown in FIG. 3, when the quality monitoring unit 16 of the content distribution server 10 reaches the generation timing of the stream data such as when a certain time has elapsed from the reference time (S101: Yes), the quality monitoring unit 16 communicates with the designated terminal device 1. The quality of the wireless communication is measured (S102).

  Subsequently, the license receiving unit 17 receives license information from the license server 5 (S103). Thereafter, the timing generation unit 18 generates a ternary number sequence from the received license information (S104). Here, the number of generated ternary sequence is S [N].

  Subsequently, the timing generation unit 18 generates a clock group using a virtual clock whose reference time is 0 (S105). Then, the timing generation unit 18 assigns each ternary string generated in S104 to the clock group generated in S105 (S106).

  Thereafter, the timing generation unit 18 specifies the current group number (S107), and specifies the ternary number corresponding to the current group number (S108). The ternary number specified here is S [N1].

  Then, the timing generation unit 18 determines the switching timing based on the value of S [N1] (S109). For example, S [N1] is one of 0, 1, and 2.

  Subsequently, the stream generation unit 19 generates a stream that switches according to the communication quality at the determined timing (S110). Thereafter, the distribution unit 20 distributes the generated stream to the terminal device 1 (S111).

[Concrete example]
Next, specific examples of generation of digital watermark data and generation of stream data will be described.

(Example of digital watermark data generation)
FIG. 4 is a diagram illustrating an example of generation of digital watermark data according to the first embodiment. As shown in FIG. 4, the content distribution server 10 accepts “date and time (7/11), user (user ID)” as license information. Then, the content distribution server 10 converts each of the date and time “7/11” and “user ID” into hexadecimal numbers and calculates “7, B, 5, 7, 9” (S201).

  Then, the content distribution server 10 converts “7, B, 5, 7, 9” expressed in hexadecimal numbers into binary numbers and calculates “0111, 1011, 0101, 0111, 1001” (S202). ).

  Subsequently, the content distribution server 10 changes “0111, 1011, 0101, 0111, 1001” expressed in binary number to a 3-bit delimiter, and “011, 110, 110, 101, 011, 110, 010”. Is calculated (S203).

  Further, the content distribution server 10 converts each of “011, 110, 110, 101, 011, 110, 010” changed to the 3-bit delimiter into a decimal number, and outputs “3, 6, 6, 5, 3, 6, 2 "is calculated (S204).

  After that, the content distribution server 10 converts each of “3, 6, 6, 5, 3, 6, 2” expressed in decimal numbers into ternary numbers, and “10, 20, 20, 12, 10, 20, 02 "is calculated (S205).

  “10, 20, 20, 12, 10, 20, 02” generated in this way is digital watermark data, which is information for identifying a distribution date and time, a distribution destination, and the like. That is, by embedding the digital watermark data “10, 20, 20, 12, 10, 20, 02” in the stream data, the distribution date and time, the distribution destination, and the like can be identified from the stream data after distribution.

(Stream data generation example)
FIG. 5 is a schematic diagram illustrating an example of generating stream data according to the first embodiment. Here, an example will be described in which radio quality deteriorates and switching from high quality to medium quality. As shown in FIG. 5, the content distribution server 10 calculates “10, 20, 20, 12, 10, 20, 02” as digital watermark data.

  Then, the content distribution server 10 generates a clock number group using “12:00: 00” as a reference time (S301). Here, the clock number “12:00:00” is expressed as “00”. Specifically, the content distribution server 10 includes group 1 “00, 01, 02, 03”, group 2 “04, 05, 06, 07”, group 3 “08, 09, 10, 11”, group 4 “ 12, 13, 14, 15 "and the like are generated.

  Thereafter, the content distribution server 10 associates each digit of the digital watermark data with each group to generate a stream (S302). Specifically, the content distribution server 10 associates “0, 1, 2, 3” in order from the smallest clock number in each group. For example, the content distribution server 10 associates “0, 1, 2, 3” with the group 1 “00, 01, 02, 03” and “groups“ 04, 05, 06, 07 ”with“ 0, 1, 2, 3 "are associated.

  Further, the content distribution server 10 associates “1” of the top “10” of the digital watermark data with the group 1 and associates “0” of the digital watermark data “10” with the group 2. Similarly, the content distribution server 10 associates “2” of the next data “20” of the digital watermark data with the group 3 and associates “0” of the digital watermark data “20” with the group 4. Further, the content distribution server 10 associates “2” of the next data “20” of the digital watermark data with the group 5 and associates “0” of the digital watermark data “20” with the group 6.

  Thereafter, the content distribution server 10 switches the stream data with a clock number corresponding to the digital watermark data among the clock numbers in each group. For example, the content distribution server 10 uses high-quality S1 data up to “01” corresponding to “1” of the top “10” of the digital watermark data in the group 1. Subsequently, the content distribution server 10 uses medium-quality S2 data from “01” of group 1 to “04” corresponding to “0” of the top “10” of the digital watermark data in group 2. Further, the content distribution server 10 uses high-quality S1 data from “04” in group 2 to “10” corresponding to “2” in digital watermark data “20” in group 3.

  Further, the content distribution server 10 uses medium-quality S2 data from “10” of group 3 to “12” corresponding to “0” of digital watermark data “20” in group 4. Next, the content distribution server 10 uses high-quality S1 data from “12” of group 4 to “18” corresponding to “2” of digital watermark data “20” in group 5. Furthermore, the content distribution server 10 uses medium-quality S2 data from “18” of group 5 to “20” corresponding to “0” of digital watermark data “20” in group 6.

  That is, the content distribution server 10 generates stream data in which one digit of digital watermark data is embedded in each group. Specifically, the content distribution server 10 is “1” for group 1, “0” for group 2, “2” for group 3, “0” for group 4, and “2” for group 5. In group 6, “0” can be embedded.

[effect]
In this way, the content distribution server 10 generates stream data that switches to a different bit rate with a clock number corresponding to one digit of the digital watermark data among the clock numbers in each group.

  Therefore, even after the stream data is distributed, the digital watermark data can be detected by detecting the timing at which the bit rate is switched in the stream data acquired from the terminal device 1. As a result, the content distribution server 10 in which the digital watermark is embedded can be realized at low cost.

  For example, even when distribution by mpeg-dash or the like is performed, it is conceivable to incorporate a function extension for a conventional Web server into the content distribution server 10. Moreover, a more preferable distribution system can be constructed by applying it to content distribution such as AV data stream distribution service for smartphones and e-learning in public facilities and educational facilities.

  In the first embodiment, the example in which the wireless quality is measured at the generation timing of the stream data and the bit stream is switched based on the measurement result is described. However, the present invention is not limited to this. For example, the content distribution server 10 can measure the wireless quality at each generated timing, and can switch to a bit stream based on the measurement result. Therefore, in the second embodiment, an example will be described in which the radio quality is measured at each generated timing and the bit stream is switched.

[Process flow]
FIG. 6 is a flowchart illustrating a flow of distribution processing for measuring quality at each switching timing according to the second embodiment. As shown in FIG. 6, S401 to S409 are the same as the processes from S101 to S109, and thus detailed description thereof is omitted.

  The content distribution server 10 that has determined the switching timing distributes the stream data of the bit rate corresponding to the wireless quality measured in S402 (S410). Then, when the switching timing is reached (S411: Yes), the content distribution server 10 measures the communication quality (S412), switches to a bit rate corresponding to the measured result, and distributes the stream data (S413).

  Thereafter, the content distribution server 10 returns to S411, distributes the stream data of the same bit rate until the switching timing is reached, and when reaching the switching timing, measures the communication quality and switches to the bit rate according to the measured result. And deliver.

[Streaming distribution example]
FIG. 7 is a diagram illustrating an example of streaming delivery according to the second embodiment. As shown in FIG. 7, the electronic watermark data, the group of clock numbers, the correspondence between the electronic watermark data and the group, and the like are the same as in the first embodiment, and thus detailed description thereof is omitted.

  As shown in FIG. 7, the content distribution server 10 distributes high-quality S1 data until it reaches “01” of group 1 that is the first switching timing, and reaches “01” of group 1 that is the switching timing. Then, the wireless quality is measured.

  Subsequently, since the wireless quality has deteriorated, the content distribution server 10 switches from “01” in group 1 to medium-quality S2 data for distribution. Thereafter, when the content distribution server 10 reaches “04” of group 2 which is the next switching timing, the content distribution server 10 measures the wireless quality.

  Then, since the wireless quality has further deteriorated, the content distribution server 10 switches from “04” in group 2 to low-quality S3 data for distribution. Thereafter, when the content distribution server 10 reaches “10” of the group 3 which is the next switching timing, the content distribution server 10 measures the wireless quality.

  Subsequently, since the wireless quality has been improved, the content distribution server 10 switches from “10” in group 3 to high-quality S1 data for distribution. After that, when the content distribution server 10 reaches “12” of the group 4 that is the next switching timing, the content distribution server 10 measures the wireless quality.

[effect]
As described above, the content distribution server 10 can embed the digital watermark data and simultaneously distribute the bit rate according to the quality at the switching timing. Accordingly, since the stream corresponding to the quality can be received even at the distribution destination, it is possible to reduce uncomfortable feeling in the reproduction of the stream at the distribution destination.

  In the first and second embodiments, the example in which the bit rate is switched has been described. However, the present invention is not limited to this. For example, the rate of the bit rate distributed in the stream can be changed. In the third embodiment, an example in which the ratio of the bit rate distributed in the stream is changed will be described.

[Process flow]
FIG. 8 is a flowchart illustrating the flow of a process for changing the stream ratio according to the third embodiment. As shown in FIG. 8, when the content distribution server 10 reaches the generation timing of the stream data such that a certain time elapses from the reference time (S501: Yes), the quality of wireless communication with the designated terminal device 1 is reached. “Q” is measured (S502).

  Subsequently, the content distribution server 10 receives the license information from the license server 5 (S503), and generates digital watermark data (N) from the received license information (S504).

  Thereafter, the content distribution server 10 calculates a ratio “P = Q + (N / 10)” (S505), generates a stream according to the calculated ratio (S506), and distributes the generated stream (S507).

  The content distribution server 10 can store a table in which the quality to be used is associated with the ratio for each wireless quality, and can specify the ratio from the wireless quality “Q” measured in S502.

  For example, the content distribution server 10 may use “wireless quality (Q), quality and ratio to be used (high quality: 31, medium quality: 69)”, “wireless quality (P), quality to be used and ratio (high quality: 11). , Medium quality: 69, low quality: 20) ", etc. can also be stored.

[Specific Example 1]
FIG. 9 is a diagram illustrating a specific example 1 of ratio change according to the third embodiment. As shown in FIG. 9, it is assumed that the content distribution server 10 calculates S1 = 31/100 and S2 = 69/100 as the stream ratio.

  In this case, the content distribution server 10 distributes high-quality S1 data for 3.1 seconds at intervals of 10 seconds, and distributes medium-quality S2 data for the remaining 6.9 seconds. In this way, the content distribution server 10 changes the bit rate ratio.

[Specific Example 2]
FIG. 10 is a diagram for explaining a specific example 2 of the ratio change according to the third embodiment. As shown in FIG. 10, it is assumed that the content distribution server 10 calculates S1 = 31/100 and S2 = 69/100 as the stream ratios, as in FIG. Here, as an example, 10-second stream data will be described.

  As shown in FIG. 10, the content distribution server 10 adds 31 every 0.1 seconds from 0 seconds, and uses medium-quality S2 data until 100 is exceeded. Then, since the addition value becomes 124 in 0.3 seconds, the content distribution server 10 uses high-quality S1 data from 0.3 seconds to 0.1 seconds and subtracts 100 from the addition value 124. After that, the content distribution server 10 becomes the addition value (124−100 = 24) at the time of 0.4 seconds, and is less than 100, so the medium-quality S2 data is used again.

  Subsequently, the content distribution server 10 continues to use medium-quality S2 data, and since the addition value becomes 117 at the time of 0.6 seconds, the high-quality S1 is used from 0.6 seconds to 0.1 seconds. Using the data, 100 is subtracted from the added value 117. Thereafter, the content distribution server 10 reaches the added value (117−100 = 17) at the time of 0.7 seconds, and is less than 100, so the medium-quality S2 data is used again.

  As described above, the content distribution server 10 performs S2 data from 0.0 seconds to 0.3 seconds, S1 data from 0.3 seconds to 0.4 seconds, and S2 data from 0.4 seconds to 0.6 seconds. Data, a stream using S1 data can be generated from 0.6 seconds to 0.7 seconds. Therefore, the content distribution server 10 can generate and distribute a stream with the bit rate switched while maintaining “S1: S2 = 31: 69”. Therefore, the distribution destination and the like can be uniquely identified by changing the bit rate ratio according to the user and the distribution date and time.

[Specific Example 3]
FIG. 11 is a diagram for explaining a specific example 3 of the ratio change according to the third embodiment. The example shown in FIG. 11 is an example in which the ratio is changed according to the value of the digital watermark data. Here, it is assumed that the digital watermark data is “10, 20” and a reference signal whose switching timing is determined is set.

  When the digital watermark data is “2”, the content distribution server 10 increases the high quality data by +2 seconds, and when the digital watermark data is “1”, the content distribution server 10 increases the high quality data by 1 second, In the case of “0”, the low quality data is incremented by one second.

  For example, since the digital watermark data corresponding to the first switching timing of the reference signal is “1”, the content distribution server 10 increases the high-quality data by 1 second without switching at this timing, and then reduces the low-quality data. Switch to.

  Subsequently, since the digital watermark data corresponding to the next switching timing is “0”, the content distribution server 10 switches to high quality data after increasing the low quality data by 1 second without switching at this timing. .

  Furthermore, since the digital watermark data corresponding to the next switching timing is “2”, the content distribution server 10 switches to the low quality data after increasing the high quality data by 2 seconds without switching at this timing.

  Furthermore, since the digital watermark data corresponding to the next switching timing is “0”, the content distribution server 10 does not switch at this timing, and switches to high quality data after increasing the low quality data by 1 second.

  As described above, the content distribution server 10 can generate a stream in which the switching timing is dynamically controlled by the digital watermark data, so that the switching timing can be uniquely controlled according to the distribution destination user, date and time, and the like.

  Although the embodiments of the present invention have been described so far, the present invention may be implemented in various different forms other than the embodiments described above. Therefore, different embodiments will be described below.

(Match)
In the above embodiment, the example in which “0, 1, 2” is assigned in ascending order of the clock numbers in the group has been described for all clock groups. However, the present invention is not limited to this. For example, the association can be changed for each group.

  For example, the group 1 “00, 01, 02, 03” is associated with “0, 1, 2, −”, and the group 2 “04, 05, 06, 07” is “1, 0, −2,”. Can also be associated. Here, “−” indicates that there is no association, “0, 1, 2” corresponds to one digit of the digital watermark data, and “00, 01” corresponds to the clock number.

  Here, how to associate with which group can be determined based on, for example, date, type of content distribution server, distribution destination, and the like.

  In addition, it is possible to arbitrarily change which three group numbers among the four group numbers of each group are selected and associated with one digit of the digital watermark data. For example, the group 1 “00, 01, 02, 03” is associated using “00, 01, 02”, and the group 2 “04, 05, 06, 07” is “04, 06, 07”. The association can be performed using. How to select three group numbers can be determined based on, for example, date, type of content distribution server, distribution destination, and the like.

(encryption)
In the above-described embodiment, the example in which the digital watermark data is generated using the date and time and the user ID in the license information has been described. However, the present invention is not limited to this. For example, other information included in the license information may be used.

  Further, the content distribution server 10 performs an exclusive OR (“7190579” connecting the date (7/19) and the user ID (0579) with a value such as “3A9F” or a base station ID that changes depending on the date. XOR) is calculated. Then, the content distribution server 10 can generate the digital watermark data by executing the above process using the exclusive OR calculation result as the license information.

(system)
In addition, among the processes described in the present embodiment, all or a part of the processes described as being automatically performed can be manually performed. Alternatively, all or part of the processing described as being performed manually can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above-described document and drawings can be arbitrarily changed unless otherwise specified.

  Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. That is, the specific form of distribution and integration of each device is not limited to the illustrated one. That is, all or a part of them can be configured to be functionally or physically distributed / integrated in arbitrary units according to various loads or usage conditions. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

(hardware)
Next, a hardware configuration example of the content distribution server will be described. FIG. 12 is a diagram illustrating a hardware configuration example of the content distribution server. As shown in FIG. 12, in the content distribution server 10, a NIC (Network Interface Card) 10a, an input device 10b, a display device 10c, a storage device 10d, and a CPU (Central Processing Unit) 10e are connected by a bus 10f.

  The NIC 10a is a communication interface and controls wireless communication and wired communication between other devices. The input device 10b is, for example, a mouse or a keyboard, and accepts an operation from an administrator or the like. The display device 10c is a display or a touch panel, for example, and displays various types of information.

  The storage device 10d is, for example, a memory or a hard disk, and stores programs executed by the CPU 10e and various data. For example, the storage device 10d stores each DB illustrated in FIG.

  The CPU 10e is a processing unit that controls the entire server apparatus, and reads various programs and executes processes. For example, the CPU 10e executes a process for realizing the same function as each processing unit described in FIG.

  In this way, the content distribution server 10 operates as an information processing apparatus that executes the process resumption method by reading and executing the program. Further, the content distribution server 10 can realize the same function as the above-described embodiment by reading the program from the recording medium by the medium reading device and executing the read program. Note that the program referred to in the other embodiments is not limited to being executed by the content distribution server 10. For example, the present invention can be similarly applied to a case where another computer or server executes the program or a case where these programs cooperate to execute the program.

1 terminal device 5 license server 10 content distribution server 11 communication control unit 12 storage unit 13 license DB
14 Stream DB
DESCRIPTION OF SYMBOLS 15 Control part 16 Quality monitoring part 17 License acceptance part 18 Timing generation part 19 Stream generation part 20 Distribution part

Claims (7)

A generation unit for generating a plurality of timings using at least one of identification information for identifying a date and time of delivery of content, a location, and a user of a delivery destination;
A content distribution apparatus comprising: a distribution unit that distributes the content by switching a bit rate of stream data corresponding to the content at each timing generated by the generation unit.   The distribution unit divides a clock number representing an elapsed time from a reference time for starting distribution of the stream data into a plurality of groups, and associates the clock number in each group with each timing based on a predetermined condition. The content distribution apparatus according to claim 1, wherein the content is distributed by switching the stream data at the timing of the elapsed time represented by the associated clock number.   The distribution unit generates the plurality of groups each including four clock numbers, and associates the timings with the respective timings using predetermined three clock numbers among the four clock numbers in each group. Item 3. The content distribution device according to Item 2.   The content distribution according to claim 1, wherein the distribution unit distributes the content by switching to a bit rate corresponding to communication quality with the distribution destination at each timing generated by the generation unit. apparatus.   The distribution unit distributes stream data obtained by inverting flag bits included in the stream data before switching when there is no change in communication quality to the distribution destination at the timing of switching to the stream data. The content distribution apparatus according to claim 4. Computer
Generate multiple timings using at least one of the date / time, location, and destination user for delivering the content,
A content distribution method comprising: processing for distributing the content by switching a bit rate of stream data corresponding to the content at each generated timing. On the program computer,
Generate multiple timings using at least one of the date / time, location, and destination user for delivering the content,
A content distribution program that executes a process of distributing the content by switching a bit rate of stream data corresponding to the content at each generated timing.

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