JP4408811B2 - Stream server - Google Patents

Description

  The present invention relates to a stream server, and more particularly, to a stream server that distributes live content and contents using the Internet or the like based on streaming technology as a medium.

  In recent years, networks such as the Internet are becoming broadband with the spread of ADSL and wireless LAN. Accordingly, a multi-media / multi-channel communication environment for transmitting / receiving data, audio, video, etc. has been rapidly established. Furthermore, the constant connection is generalized, the integration of information appliances and networks is promoted, and the demand for content distribution such as video / music and live distribution is expanding.

  In such a network, it is important to distribute live and content by streaming technology that multiplexes multimedia and handles it as one digital information flow.

  FIG. 10 shows an example of conventional live distribution and content distribution. When the user terminal (PDA) 170_2 requests distribution of the live 720, if the cache server 150_2 does not hold the live 720, the live 720 captured by the video input device 120 is given to the real-time encoder 130.

  The encoder 130 converts the live 720 into data of the requested encoding method and encoding rate, and transmits the data to the user terminal 170_2 via the live distribution 720a via the IP network 140 and the cache server 150_2. At this time, the cache server 150_2 temporarily stores the live 720.

  When the user terminal (mobile phone) 170_3 requests distribution of the live 720 having the same encoding method and encoding rate, the cache server 150_2 transmits the stored live 720 to the user terminal 170_3 through the live distribution 720b.

  The content 710 is stored in the source database 700 of the content server 110. When the user terminal (desktop PC) 170_1 requests distribution of the content 710, if the cache server 150_1 does not store the content 710, the content 710 passes from the content server 110 via the IP network 140 and the terminal adapter (TA) 160. Then, the content distribution 710a is performed to the user terminal 170_1.

  At this time, the cache server 150_1 temporarily stores the content 710. Thereafter, for example, the operation of the cache server 150_1 when there is a distribution request for the content 710 from the user terminal 170_2 is the same as that of the cache server 150_2.

  The live distribution 720a, 720b and the content distribution 710a are performed by, for example, an MPEG stream that performs decompression processing with reference to reference data.

  The IP network 140 is basically a best-effort type, and is not adapted for delivery without interrupting the MPEG stream for a long time.

  As conventional techniques for solving this problem, for example, a real-time transport protocol (hereinafter referred to as RTP), a real-time transport control protocol (hereinafter referred to as RTCP), and There are streaming technologies such as Real Time Streaming Protocol (hereinafter referred to as RTSP).

  RTP is a transmission protocol that defines a packet format for transmitting audio data and video data so that media synchronization is possible on the receiving side. RTSP is a protocol that performs stream control, such as starting and suspending content distribution. RTCP is a protocol that defines a procedure for transmitting information necessary for flow control on audio and video streams and reference time information for media synchronization.

  With these protocols, more comfortable RTP streams (content distribution or live distribution) taking into account the given environment, such as negotiation between the user terminal and the distribution source, network load at the time of data distribution, and processing capacity of the user terminal, are real-time. It is controlled by.

  However, in a conventional streaming environment, live distribution is performed by distributing data at a plurality of fixed encoding rates from an stream server (distribution side) to an unspecified number of user terminals (reception side). Yes.

  The user terminal selects and receives data from a plurality of encoding rate data fixed from the distribution source according to its own processing capability. Therefore, comfortable multicast-type content distribution and live distribution in which the network load and the processing capacity of the user terminal are considered in real time are not realized for a large number of unspecified user terminals.

  That is, in the conventional streaming environment, in content distribution, not only one encoding method (one source) but also data corresponding to each user terminal (multi-use) is distributed not only in the encoding method but also in the real-time optimum encoding rate. It is difficult to do.

  In order to solve this, enormous hardware such as real-time encoders for the number of user terminals or a database of data of all coding rates is required, which is not practical.

  In other words, it is not possible to achieve one-source / multi-use that covers not only contents and encoding methods but also encoding rates.

  Also, in live distribution, the real-time encoder 130 distributes real-time encoded data as it is to the network, so it is difficult for the user terminal to expand communication (selectivity) such as rewinding and pausing to the content server. is there.

  Therefore, the user terminal must receive a service considering that content distribution and live distribution are different. In addition, in the distribution server, the content server and the live server are independent devices, and it is necessary to control them independently, and it is difficult to merge the content distribution and the live distribution.

  In content distribution, since a plurality of encoded data corresponding to the content is stored in a database in advance, all content data is stored in a database regardless of movie content viewed by many users and personal video content viewed only by a certain individual user. And a huge database capacity is required.

  For this reason, there is a limit to the construction of a personal database that stores digital contents originally produced by individual users, which is a recent trend.

  In content distribution, the database stores compressed encoded data, and it is difficult to insert / delete the sequence header at an arbitrary position in the MPEG stream. It is difficult to change the optimum encoding rate / resolution considering the output function, access line type, network congestion, user terminal processing capability, and the like.

  Also, in conventional content distribution or live distribution, the distribution server and the cache server (edge server) are independently deployed and operated independently, and the cache server is the content requested from the user terminal (receiving side) or live, encoded Hit / miss judgment considering the method is possible.

  However, it is not possible to manage the start / stop / change of the request data in consideration of the encoding rate determined by negotiation or feedback of an RR (Receiver Report) type RTCP packet from the user terminal as a trigger. Therefore, it is difficult to perform hit / miss determination in consideration of the audience rating.

  In conventional content distribution or live distribution, a stream server is operated in response to an action from a user terminal, such as during negotiation operation or feedback of an RR type RTCP packet in streaming.

  Therefore, when viewing requests from an unspecified number of users overlap at the date and time when the distribution of a certain movie content starts, many access conflicts to the transcoder occur, and the responsiveness of the distribution service to the user terminal is increased. It becomes difficult.

  In addition, a cache server (edge server) in conventional content distribution or live distribution stores various contents or data such as live data, encoding method, encoding rate, etc., and whether there is data requested by the user terminal. Since the check is performed on all stored data, the hit / miss judgment circuit requires a huge hardware scale.

  In addition, conventional content distribution or live distribution has a distribution server and a cache server (edge server) that are independently deployed and operated independently, and new content or live content that is not stored in the cache server (edge server) from the user terminal. When a new encoding method and a new encoding rate are requested, a miss determination is made.

  Accordingly, since the distribution server distributes data corresponding to the content and the encoding method to the cache server, the cache server must always discard already stored data.

  In addition, in the hit / miss judgment of the cache server (edge server), the congestion level on the distribution server side is not taken into account, so if the distribution server is not responsive, the throughput of the distribution data will be reduced and fluctuations will occur. .

  Further, in the conventional hierarchical encoding, when changing the encoding rate or resolution of certain hierarchical data, the hierarchical processing is referred to as reference data and the encoding process is performed.

  Thereafter, since it is necessary to regenerate all the upper layer data, a huge amount of hardware is required, and the number of times of use of resources such as a transcoder is increased (it is difficult to effectively use resources).

  Therefore, the present invention aims at the following items (1) to (9) in a stream server that distributes live and content using the Internet or the like by a streaming technique or the like as a medium.

 (1) Content distribution or live distribution corresponding to a given environment, that is, network load, processing capacity of the user terminal, congestion level of the stream server, or the like in real time is performed for an unspecified number of user terminals.

 (2) Integration of content distribution and live distribution is realized with a small amount of hardware.

 (3) Reduce the required database capacity.

 (4) Realize one-source multi-use that supports not only the requested content and encoding method, but also the required encoding rate.

 (5) It is possible for the user terminal to perform arbitrary cueing, optimum coding rate change, and resolution change corresponding to the access line type, network congestion level, and user terminal processing capability.

 (6) Provide content or live distribution service corresponding to audience rating.

 (7) Speed up the determination of the presence or absence of data requested by the user.

 (8) To reduce hit mistakes in data of new contents or new live requested by the user, new encoding method, and new encoding rate.

 (9) To improve the efficiency of changing the coding rate and resolution in hierarchical coding.

Prior art documents

-JP2000-228669-JP2001-54095-JP2001-54094-JP10-108160-JP2000-299702

In order to solve the above problems, the stream server of the present invention includes one or more transcoders, a cached database for storing data, and data requested for content or live, encoding scheme, and encoding rate. Is not stored in the cache type database, a hit / miss determination unit that controls the transcoder and the cache type database in cooperation with each other so that the requested data is stored in the cache type database. provided, the hit / miss judgment unit searches for further requested content or live, and closest coding rate on the inner the requested coding rate coding rate corresponding to the encoding scheme, which is the required When the absolute difference between the encoding rate and the encoding rate closest to the retrieved request is less than or equal to a predetermined threshold The request data it is and determines that that are stored in the cache database.

  That is, as usual, the transcoder converts the designated content or live into data of the designated coding rate of the designated coding method. This data is stored in the cache database.

  The hit / miss determination unit is configured to store the requested data in the cache type database when the requested data regarding the encoding method and the encoding rate is not stored in the cache type database. Type database controls in cooperation.

  Thereby, the cache type database stores, for example, the content or live requested from the user terminal as data of the requested encoding rate of the requested encoding method, and each user terminal stores the requested code. It is possible to realize content distribution or live distribution at a coding rate of the encoding method.

  It should be noted that the cache type database and transcoder mentioned here are assumed to be included in the respective control / arbitration units described later, but in the following, the cache type database is divided into a cache type database main body and its control / arbitration unit, The coder may be displayed separately for the transcoder and its control / arbiter.

Further, the transcoder can be a encoder or CODEC.

That is, the transcoders, CODEC, and shall include an encoder. For example, in the case of live distribution, an encoder can be used instead of a transcoder.

In addition, the cache database may have a plurality of lines for storing the data at different encoding rates for the same content or live and encoding schemes.

  In other words, the cache database has a plurality of lines, and for example, data converted into different encoding rates for the same content and encoding scheme is stored in each of these lines.

  As a result, multicast content distribution or live distribution is realized for an unspecified number of user terminals. That is, it is possible to realize one-source multi-use that distributes content or live, an encoding method, and an encoding rate corresponding to each user terminal.

Further, between the User chromatography The terminal, call control, or start control of the distribution of the data, pause control, or rewind negotiate about control, call control for notifying the result to the hit / miss judgment unit It is possible to further include a / negotiation processing unit, and the hit / miss determination unit can perform cooperative control on the transcoder and the cache type database based on the result.

  That is, the call control / negotiation processing unit performs call control or start control, temporary stop control, or rewind negotiation with the user terminal.

  Based on this result, the hit / miss determination unit performs the start, pause, or rewind control of the data stored in the cache database.

  This enables start, pause, and rewind control for content distribution, and also enables start, pause, and rewind control for live distribution by performing live distribution after storing the data in a cache database. .

  The present invention further monitors at least one of the network load with the user terminal, the congestion level of the content server, or the processing capability of the user terminal, and gives the monitoring result to the hit / miss determination unit. A hitch / miss determination unit can determine the optimum encoding rate based on the monitoring result.

  That is, the network monitoring unit monitors the network load with the user terminal, the congestion level of the content server, or the processing capability of the user terminal. Based on the monitoring result, the hit / miss determination unit determines an optimum encoding rate for each user terminal.

  As a result, for example, content distribution or live distribution at an encoding rate that considers the network load, the congestion level of the content server, the current processing capability of the user terminal, and the like in real time becomes possible.

  That is, it becomes possible to control more comfortable content distribution or live distribution in real time for a user in a given environment.

Further, in the above, it is possible to further include a protocol implementation processing unit that implements a predetermined protocol and performs communication processing with the user terminal based on the predetermined protocol.

  That is, the protocol implementation processing unit implements a protocol for performing communication processing between the stream server and the user terminal. Based on this implemented protocol, content distribution or live distribution and their control can be performed.

Further, the protocol implementation processing unit can include at least one of an IP header processing unit, a UDP header processing unit, an RTP header processing unit, an RTCP header processing unit, and an RTSP header processing unit.

  This makes it possible to perform content distribution or live distribution and control thereof based on protocols such as IP, UDP, RTP, RTCP, and RTSP.

In addition, the protocol implementation processing unit can include an MPEG sequence header processing unit.

  As a result, it is possible to easily change the optimum encoding rate and resolution of the MPEG encoding method, and to search for an arbitrary video in consideration of the access line type, network congestion level, or user terminal capability.

Further, the transcoder may convert at least one of the input material data, transcode data, and live data into data of a specified encoding rate of the specified encoding method. it can.

  That is, the transcoder can input material data or transcode data from a source database device, for example, and can input live data from a video input device and convert it into the data.

  The connection between the stream server, the source database device, and the video input device may be either a direct connection or a connection via a network.

In addition, the hit / miss determination unit determines the order of the requested content or live search, the search for the encoding method, the search for the encoding rate, and the search for whether the data is valid or not in a predetermined order. It is possible to perform hit / miss judgment of request data.

  That is, the hit / miss determination unit, for example, searches for the requested content or live and its encoding method, searches for the encoding rate, and the hit / miss of the requested data in the search order of whether the data is valid. Make a mistake decision.

  This facilitates hit / miss determination and enables a significant reduction in hardware.

The hit / miss determination unit determines whether the requested content or live, encoding method, and encoding rate data is stored in the cache type database. It can be determined whether or not it is within the allowable range.

  That is, when the hit / miss determination unit determines whether or not the requested content or data converted to live, encoding method, and encoding rate is stored in the cache type database, for example, Therefore, it is considered that data having an encoding rate that is not within the same encoding rate as the requested encoding rate but within an allowable range from the requested encoding rate is hit.

  As a result, instead of the requested encoding rate, it is possible to distribute data of an encoding rate within an allowable range, and it is not necessary to store data of all the requested encoding rates, which is efficient. In addition, it is possible to operate a cache type database and realize stable content distribution and live distribution.

In addition, when the hit / miss determination unit does not store the requested content or live, encoding method, and encoding rate data in the cache database, the requested content or live, request The coding method, discarding data at a coding rate close to the requested coding rate, and storing the requested data at the location where the data was stored. The cache type database can be controlled in cooperation.

  That is, when the requested content or live, encoding method, and encoding rate data are not stored in the cache-type database, the hit / miss determination unit requests the requested content or live. However, the data of the encoding rate close to the requested encoding rate is retrieved and discarded.

  The hit / miss determination unit controls the transcoder and the cache database in cooperation with each other so that the requested data is stored at the position where the data is stored.

  This makes it possible to distribute the requested data to the user terminal.

In addition, the hit / miss determination unit described above can discard content data or live data with a low audience rating, or data with a coding rate with a low audience rating.

  As a result, the size of the cache database can be reduced, and content with high audience rating or live data can be retained, and the hit rate of the cache database is also increased.

In addition, the cache type database stores the viewing start time information, stop time information, and change time information for the requested data given from the network monitoring unit, and the hit / miss determination unit The hit / miss determination can be performed based on the information.

  That is, the cache type database stores the viewing start time information, stop time information, and change time information for the requested data given from the network monitoring unit. The hit / miss determination unit calculates, for example, a real-time audience rating based on the information, and performs hit / miss determination based on the audience rating.

  Thereby, for example, the hit / miss determination unit can perform hit / miss determination in consideration of real-time audience rating.

In addition, the hit / miss determination unit discards at least one of content data or live data with low audience rating, encoding method with low audience rating, or data with encoding rate with low audience rating, The transcoder and cache database can be instructed to store the requested content or live, encoding scheme, and encoding rate data where the discarded data was stored.

  That is, the hit / miss determination unit, for example, when there is no location in the cache database that stores the requested content or live, encoding method, and encoding rate data, the content data or live data with low audience rating The data of the encoding method of the low audience rating or the data of the encoding rate of the low audience rating is discarded.

  Then, the requested content or live data, encoding method, and encoding rate data are stored in the location where the discarded data was stored.

  This makes it possible to secure a location for storing the requested content or live, encoding method, and encoding rate data.

  In addition, it is possible to reduce the size of the cache type database, and contents or live data with a high audience rating continue to be retained.

  As a result, the hit rate of the cache database is also increased, and an efficient operation of the cache database can be realized.

In addition, when there is an unused transcoder, the hit / miss determination unit controls the transcoder and the cache type database so that new content or new live is converted into data of a predetermined encoding method at a predetermined encoding rate. It can be converted and stored in the cache database.

  That is, when there is new content or new live and there is a transcoder that is not used, the hit / miss determination unit converts the new content or new live into data of a predetermined encoding method at a predetermined encoding rate. The transcoder and the cache type database are controlled so as to be stored in the cache type database.

As a result, the transcoder, for example, converts the new content into data of a predetermined encoding rate with a predetermined encoding method in advance when the requested content is not converted and when the cache database is empty. It becomes possible. As a result, it is possible to avoid access conflict between the transcoder and the cache type database, and it is possible to realize effective use of resources. In addition, in the present invention, the transcoder is based on spatial scalability, temporal scalability, or SNR scalability. In the hierarchical coding, only the encoded data of the coding rate change target layer and the one higher layer thereof is newly created, and the difference between the decoded data expanded from the new higher layer and the decoded data expanded from the current higher layer When the sum of absolute values is less than or equal to a predetermined threshold, the newly created change target hierarchy and higher hierarchy can be made the current hierarchy.

  As a result, the target coding rate can be changed without affecting the coding rate data used elsewhere.

  Moreover, it is not necessary to newly create all the upper layer data by simply creating the coding rate change target layer and its upper layer, and a huge amount of hardware is not required. Resource usage can be reduced.

  FIG. 1 shows an embodiment of a stream server 100 according to the present invention. The server 100 includes a transcoder control / arbitration unit 10, transcoders 20_1 to 20_L (hereinafter, may be collectively referred to as reference numeral 20), a database control / arbitration unit 30, a cache database 40, and a hit / miss determination unit 50. , A network monitoring unit 60, a call control / negotiation processing unit 70, and a protocol implementation processing unit 80.

  The cache database 40 stores content data or live data (hereinafter, content data and live data may be collectively referred to as content data). It consists of

  The protocol implementation processing unit 80 includes an IP header processing unit 81, a UDP header processing unit 82, an RTP header processing unit 83, an MPEG sequence header processing unit 84, an RTCP header processing unit 85, and an RTSP header processing unit 86.

  The hit / miss determination unit 50 checks whether the request data is stored in the cache database 40, the network monitoring unit 60 monitors the network using the RTCP protocol, and the call control / negotiation processing unit 70 Call control and negotiation are performed using the protocol.

  FIG. 2 (5) shows a more detailed configuration example of the cache database 40 shown in FIG. The database 40 includes a taggram (TAG RAM) 41, a taggram 42, and a cache 43.

  The taggram 41 is composed of taggrams 41_1 to 41_M including fields of “MRU (Most Recently Used)”, “content”, “encoding method”, and “address of taggram 42”.

  The tag 41 is managed in units of “content” and “encoding method”, and for example, content information and encoding method information thereof are stored in the “content” and “encoding method”, respectively.

  The “MRU” in the taggram 41 includes viewing history information such as viewing start / stop / change time information at the time of negotiation or when changing the encoding rate during network monitoring ((RR type RTCP packet feedback)) Information) is stored.

  In the “address of taggram 42” of the taggram 41, the head address of the taggram 42 corresponding to “content” and “encoding method” is stored.

  The taggram 42 is composed of taggrams 42_1 to 42_N (hereinafter, may be collectively referred to as reference numeral 42) including “MRU”, “encoding rate”, and “hierarchy” fields. Managed.

  “MRU” in the taggram 42 stores viewing history information (viewing rate information) such as viewing start / stop / change time information when the coding rate is changed.

  “Encoding rate” and “hierarchy” store encoding rate information and its hierarchy, respectively.

  The cache 43 is composed of lines 43_1 to 43_N (hereinafter may be collectively referred to as reference numeral 43) each including data 1 to data X1,..., Data 1 to data XN. Each line 43 further includes a valid field indicating validity / invalidity of each data. In the case of MPEG data, the management unit of content data stored in each data 1 to X1 is GOP (Group Of Picture).

  The lines 43_1 to 43_N correspond to the tagograms 42_1 to 42_N, respectively, and this correspondence is shown by providing a field (not shown) indicating the head address of the line 43 in the taggram 42, for example.

  FIG. (2) shows in more detail the taggram 41_1 shown in FIG. (5). The content of the management unit and the encoding method are “content 710_1” and “MPEG2”, respectively. This indicates that the MRU is viewing history 01 to viewing history 0x.

  Further, the taggram 41_1 indicates that the head addresses of the taggram 42 (encoding rate) corresponding to “content 710_1” and “MPEG2” are “0x0”, “0x1”,..., “0xy”. Yes.

  FIG. 3 (3) shows a more detailed example of the tags 42_1, 42_2,... Shown in FIG. In this example, a tagogram 42_1 designated by a taggram 42 address = “0x0” of the taggram 41_1 is shown.

  This taggram 42_1 indicates that the hierarchy of the coding rate = “1 Mbps” is “1” and the MRU is the viewing history 11 to 1X.

  As a basic operation of the stream server 100, the hit / miss determination unit 50 caches each time when the user terminal triggers [1] negotiation or when [2] RR type RTCP packet feedback (network monitoring). The hit / miss judgment of the type database 40 is performed.

  In addition, the hit / miss determination unit 50 has an opportunity other than opportunity [1] or [2] [3] unused transcoders exist, and popular content is newly stored in the source database. When not stored, the hit / miss determination of the cache database 40 is performed by an autonomous cooperative operation, and the encoded data of the popular content is stored in the cache database 40.

  Thereby, for example, even when a distribution request from an unspecified number of users at the start of popular content distribution competes, it can usually be read from a cache database. In this way, a finite number of transcoder resources can be effectively used, and the responsiveness of the distribution service to the user terminal (receiving side) can be realized.

  FIG. 3 shows a basic operation procedure of the hit / miss determination unit of the stream server 100. In the streaming technology, as shown in FIG. 2, for example, a plurality of encoding rates (1 Mbps, 5 Mbps,..., 20 Mbps) are supported for the content (or live) 710_1 and the encoding method (MPEG2).

  Therefore, the hit / miss determination unit 50 performs hit / miss determination of the cache database 40 in the following three stages (T1) to (T3).

 (T1) The taggram 41 is searched to determine whether the requested content or the live and encoding method is stored (see determination T1 in FIG. 2 (1)).

 (T2) Next, the search for the taggram 42 is searched to determine whether or not the requested encoding rate is stored (see determination T2 in FIG. 2 (1)).

 (T3) Finally, the “valid (valid) field” of the cache 43 is searched to determine whether or not the request data is stored (see determination T3 in FIG. 2 (1)).

[1] At Negotiation FIG. 4 shows an example of an operation procedure when the stream server 100 of the present invention is negotiated (trigger [1]). The operation procedure at the time of negotiation will be described below with reference to FIG.

  In this description, the case where the user terminal 170 requests the content 710 stored in the source database 700 shown in FIG. 1 will be described.

  The same applies when the user terminal requests live 720, but in the case of live distribution, an encoder can be used as the transcoder 20, and the transcoder control / arbiter 10 shown in FIG. become.

  In FIG. 4, step S100 surrounded by a broken line indicates a cache type database search procedure of the hit / miss determination unit 50, and step S200 surrounded by a broken line indicates a transcoder control / arbitration unit 10, a database control / arbitration unit 30, In addition, a transcoder entry procedure in the hit / miss determination unit 50 is shown, and step S300 surrounded by a broken line shows a protocol implementation processing procedure of the protocol implementation processing unit 80.

  In FIG. 1, a call control / negotiation processing unit 70 establishes a connection between the stream server 100 and the user terminal 170 by a call control / negotiation operation from the user terminal 170.

Steps S110 to S130 : The hit / miss determination unit 50 stores data that matches the content data requested by the user terminal 170, the encoding method, and the encoding rate, for example, the content 710_1, MPEG2, and 5 Mbps in the cache database 40. Check whether it is stored.

  That is, in FIG. 2, the hit / miss determination unit 50 receives (T0), for example, content name = content 710_1, encoding method = “MPEG2”, and encoding rate = shown from the user terminal 170 in FIG. Receives a “5Mbps” request.

  At the time of negotiation, there is no request for the GOP number shown in FIG.

  Therefore, the hit / miss determination unit 50 performs the hit / miss determination T1 shown in FIG. 1A for searching the content 710_1 and the encoding method = “MPEG2” from the tag 41 in FIG. Hit Tagram 41_1.

  Furthermore, the hit / miss determination unit 50 sets the encoding rate = “5 Mbps” from the tags 42_1 to 42_y corresponding to the head addresses = 0x0, 0x1,..., 0xy indicated in the taggram 42 address field of the taggram 41_1. The hit / miss determination T2 shown in FIG. 1 (1) to be searched is performed, and the taggram 42_2 is hit.

Step S180 : Further, the hit / miss determination unit 50 performs a hit / miss determination T3 (see FIG. 2 (4)) for determining whether or not the data of the line 43_2 corresponding to the hit taggram 42_2 is valid.

  When the encoded data is valid, the hit / miss determination unit 50 reads the valid data “1” as data 802 and gives it to the protocol implementation processing unit 80. By repeating this operation, data 1 to data X2 of the line 43_2 are sequentially given to the protocol implementation processing unit 80.

  If the data is invalid, the hit / miss determination unit 50 proceeds to step S210 of the transcoder entry.

Steps S310 to S340 : The protocol implementation processing unit 80 inserts the MPEG sequence header, RTP header, UDP header, and IP header into the data 801, and then stores them in the line 43_2 on the user terminal 170 via the IP network 140. Content distribution starts (data distribution T4 in FIG. 2 (1)).

Steps S140 to S170 : If there is a miss in step S110 or S120 (data does not exist), the hit / miss determination unit 50 searches the data unstored line 43 from the cache type database 40 or is set in advance. A search for content with an audience rating lower than the threshold a, a search for an encoding method with a low audience rating, and a search for an encoding rate with a low audience rating are performed.

  That is, the hit / miss determination unit 50 searches the data unstored line 43 in FIG. 2 (5), and if there is no (miss), the content / When the encoding method is searched and there is no (miss), the encoding rate indicating the audience rating lower than the threshold value a in the MRU of the taggram 42 is searched.

Step S210 : If one of the above searches is hit (there is a hit line), the hit / miss determination unit 50 sends the transcoder entry to the transcoder control / arbitration unit 10 and the database control / arbitration unit 30, respectively. A request signal 800 and a signal 801 are given.

  For example, when the transcoder 20_2 is not used, the transcoder control / arbiter 10 transmits the content (material or transcode) 710 requested by the user indicated by the transcoder entry request signal 800 from the source database 700 to the transcoder 20_2. To give.

  If there is no unused transcoder, the process proceeds to step S290.

Step S220 : The transcoder 20_2 provides the database control / arbiter 30 with the data subjected to the real-time encoding process for the content 710. The database control / arbiter 30 stores the encoded data in, for example, an unstored line (or low audience rating line) 43_1 in the cache database 40 (cache fill).

Step S230 : The hit / miss determination unit 50 reads the data 802 from the cache-filled line 43_2 and provides it to the protocol implementation processing unit 80.

Steps S310 to S340 : The protocol implementation processing unit 80 sequentially starts content distribution or live distribution requested by the user terminal 170 via the IP network 140 in the same manner as steps S310 to S340 described above.

Step S290 : In the above-described steps S140 to S170, when the unstored line search, the low audience rating content search, the low audience rating encoding method search, and the low audience rating encoding rate search are all missed. Alternatively, when there is no unused transcoder 20 in step S210 (transcoder entry request failed), the entry request from the user terminal 170 fails.

[2] During network monitoring FIG. 5 shows when the stream server 100 is performing content distribution or live distribution to the user terminal 170, and receives an RR type RTCP packet from the user terminal 170 (see FIG. 1). The operation procedure is shown.

  This operation procedure will be described below with reference to FIG. In FIG. 5, step S400 shows a network monitoring procedure, step S500 shows a cache type database search procedure, step S600 shows a procedure for entry into a transcoder, and step S800 shows a protocol implementation processing procedure.

Step S410 : The call control / negotiation processing unit 70 receives the RR type RTCP packet transmitted from the user terminal 170, and provides the hit / miss determination unit 50 with the feedback information included in this packet.

  The RR type RTCP packet is related to the stream reception state (packet loss rate (Fraction Lost), cumulative packet loss rate (Cumulative Number of Packet Lost), fluctuation between packet arrivals (Interarrival Jitter)). This packet feeds back information to the stream transmission side.

  Based on this information, the hit / miss determination unit 50 determines the current network congestion, the capability of the user terminal 170, etc. from the number of viewers, viewing history, packet discard rate, cumulative packet discard rate, fluctuation of packet arrival interval, etc. The optimum encoding rate is calculated in consideration of

  That is, the hit / miss determination unit 50 determines T0 in FIG. 2 (1), that is, the content name, encoding method, encoding rate, and GOP number distributed to the user terminal 170.

Step S510 : The hit / miss determination unit 50 checks whether or not the data matching the calculated optimal encoding rate is stored in the cache database 40.

  That is, the hit / miss determination unit 50 performs hit / miss determinations T1 and T2 in FIG. 2 (2) and (3) to determine whether there is an optimum encoding rate for the requested content and encoding method. .

Steps S590 and S710 : When an optimal encoding rate exists (hit), the hit / miss determination unit 50 performs hit / miss determination T3 as to whether or not the data of the line corresponding to the encoding rate is valid (same as above). refer graph1).

  When the data is hit (valid), the hit / miss determination unit 50 gives the data 802 read from the hit line 43 to the protocol implementation processing unit 80.

Steps S810 to S840 : The protocol implementation processing unit 80 sequentially distributes the optimum coding rate data 802, into which the MPEG sequence header, RTP header, UDP header, and IP header are inserted, to the user terminal 170 via the IP network 140. As a result, the optimum coding rate data 802 is delivered to the user terminal 170 following the previous coding rate data.

Steps S590 and S770 : When data is missed (invalid), this indicates a state where the requested encoding rate exists in the cache but the target data itself does not exist.

  Therefore, the hit / miss determination unit 50 provides the signal 800 and the signal 801 to the transcoder control / arbitration unit 10 and the database control / arbitration unit 30, respectively.

  Based on these signals 800 and 801, the currently used transcoder encodes the requested content into data of the requested encoding rate in the requested encoding scheme, and this data is received in step S510. Stored in the hit line 43 (cache fill).

Step S780 : The hit / miss determination unit 50 reads the data of the hit line 43 and gives it to the protocol implementation processing unit 80.

Steps S810 to S840 : The protocol implementation processing unit 80 sequentially distributes the data 802 with the MPEG sequence header, RTP header, UDP header, and IP header inserted to the user terminal 170 via the IP network 140.

  Thereby, the data of the optimum coding rate is distributed to the user terminal 170.

Steps S510 and S520 : When there is no data with the optimal encoding rate (miss), the hit / miss determination unit 50 searches the cache type database 40 for encoded data closest to the optimal encoding rate.

  That is, the hit / miss determination unit 50 in FIGS. 2 (2) and 2 (3), the optimum encoding route within the encoding rate of the tag 42 corresponding to the tag 41 corresponding to the requested content and encoding method. The closest encoding rate (comparison encoding rate) is searched.

Step S530 : When the difference absolute value x = | optimal coding rate−comparison target coding rate | is equal to or less than a preset threshold value b, the hit / miss determination unit 50 regards that the requested data exists (hit).

Step S590 : The hit / miss determination unit 50 performs a hit / miss determination T3 as to whether or not the data of the line regarded as a hit is valid, and if it is valid, reads the data and gives it to the protocol implementation processing unit 80 .

  That is, the hit / miss determination unit 50 provides the protocol implementation processing unit 80 with the valid data 802 read from the line 43 corresponding to the coding rate tag 42 that has been hit in FIGS. 2 (3) and 2 (4). Subsequent operations are the same as those in steps S810 to S840 described above.

  As a result, the data 802 having the coding rate within the allowable range, but not the data having the optimum coding rate, is distributed to the user terminal 170.

Step S540 : If the difference absolute value x is greater than the set threshold value b and less than or equal to the threshold value c, the hit / miss determination unit 50 has no request data (hit / miss determination T1, FIG. 2 (1)). (Transmission control / arbiter) because the comparison coding rate data stored in the cache database 40 is unnecessary (the coding rate is changed by the RR type RTCP packet). A transcoder entry request signal 800 is given to 10.

Steps S610 and S620 : In response to the transcoder entry request, the transcoder control / arbiter 10 performs real-time encoding using the raw data or transcoded data as a source when the unused transcoder 20 exists in the transcoder 20. Processing is performed, and the processed data is stored in the comparison target coding rate line (miss line) in the cache database 40 (cache fill).

Step S720 : The hit / miss determination unit 50 gives the data 802 read from the cache-filled line to the protocol implementation processing unit 80.

Steps S810 to S840 : The protocol implementation processing unit 80 sequentially distributes the data 801 to the user terminal 170 via the IP network 140.

  As a result, it becomes possible to fill the data of the optimum coding rate into the comparison coding rate line whose difference absolute value from the optimum coding rate is larger than the threshold value b and equal to or less than the threshold value c. This data fill also has little influence on the video and audio on the user terminal that uses the data of the comparison target coding rate line.

  When the difference absolute value is larger than the set threshold value c, if the coding rate change from the comparison target data to the request data is performed, the influence on the video and audio for the user who uses the data of the comparison target coding rate is large.

  Therefore, the hit / miss determination unit 50 performs the following determination.

Steps S550 and S630 : The hit / miss determination unit 50 searches the unstored line 43 of the cache database 40 because the difference absolute value of the comparison target encoding rate is large, and the target line exists (hit) Then, a transcoder entry request signal 800 is given to the transcoder control / arbiter 10.

Steps S640 and S730 : In response to the transcoder entry request, the transcoder control / arbiter 10 provides material data or transcode data to the unused transcoder 20 when an unused transcoder 20 exists.

  The transcoder 20 performs real-time encoding processing on the given data, and stores (cache fill) in the unstored line 43 via the database control / arbiter 30. Data 802 is read from this fill line and transmitted to the user terminal.

Steps S560 to S580 : Since there is no unstored line, the hit / miss determination unit 50 creates the content 43, the encoding method, or the encoding rate line 43 that has a viewer rating lower than the preset threshold value a from the cache database 40. If the target data is found (hit), the transcoder control / arbiter 10 is requested to make a transcoder entry.

Steps S650 and S660 : When there is an unused transcoder 20 in response to a transcoder entry request, the transcoder control / arbiter 10 provides material data or transcode data to the unused transcoder 20.

  The transcoder 20 performs real-time encoding processing on the given data and stores it in the low audience rating line 43 in the cache database 40 via the database control / arbiter 30 (cache fill).

Step S740 : The hit / miss determination unit 50 reads the data 802 from the cache-filled line 43 and gives it to the protocol implementation processing unit.

Steps S810 to S840 : The protocol implementation processing unit 80 continues to sequentially distribute the data into which the header is inserted to the user terminal.

Steps S580, S670, S680, S760 : In the search of unstored lines and viewing history lines lower than the threshold value a stored in the cache type database, if there is no target data, the hit / miss determination unit 50 A transcoder entry request signal 800 is given to the coder control / arbiter 10.

  When there is an unused transcoder, real-time encoding processing is performed on the material data or transcoded data, and the data is stored in the comparison target coding rate line 43 in the cache database 40 (cache fill). Data read from the cache-filled line 43 is supplied to the protocol implementation processing unit 80.

Steps S810 to S840 : The protocol implementation processing unit 80 continues data distribution to the user terminal 170 sequentially.

Steps S610, S630, S650, S670, S750 : When there is no unused transcoder 20, the coding rate change request based on the RR type RTCP packet fails.

  The hit / miss determination unit 50 continues to transmit data at the current encoding rate and waits for a next encoding rate change request.

  By such cooperative operation of the transcoder control / arbitration unit 10, the transcoder 20, the database control / arbitration unit 30, the cache database 40, and the hit / miss determination unit 50, the stream server 100 not only performs live distribution. Even in content distribution, real-time encoding processing can be performed in consideration of network load, processing capability of the user terminal, and the like in real time.

  Also, the stream server 100 discards the content data and live data of the encoding method of the low audience rating encoding rate, so that only the content data and live data of the encoding method of the encoding rate of the high audience rating are stored. The data is continuously stored in the cache database 40.

  As a result, normally, the high audience rating data stored in the cache database 40 can be distributed to many user terminals.

  In other words, the stream server 100 provides a comfortable multicast content distribution and live performance for unspecified users, taking into consideration the real-time network load, the processing capability of the user terminal 170, the congestion level of the stream server 100, and the like. Distribution can be realized, and “one-source multi-use” can be realized not only for contents and encoding methods but also for encoding rates.

  Further, the stream server 100 reads content distribution data and live distribution data for an unspecified number of users from a cache database that normally stores content data and live data of an encoding method with a high audience rating encoding rate. Therefore, it is not necessary to provide as many transcoders as the number of users, and the number of transcoders can be greatly reduced.

  In addition, the cache database 40 of the stream server 100 always discards low-viewing content and live content that only an individual user views, and discards high viewing-rate content and high viewing rate such as movie content that many users view. Since only live data is continuously stored, the database size can be greatly reduced, and a personal database distribution service on the stream server 100 can be facilitated.

  In addition, since the stream server 100 arranges the cache type database 40 at the subsequent stage of the transcoder 20, and stores the content data and live data in the cache type database 40 once and distributes them to the user, the stream server 100 also provides the user with the live distribution. Communication functions (selectivity) such as rewinding from the terminal (receiving side) to the stream server (distributing side) and a pause request can be expanded.

  That is, the user terminal (reception side) 170 can enjoy the service without distinguishing between live distribution and content distribution, and fusion of live distribution and content distribution is possible.

  In addition, the stream server 100 can easily change the frame rate, resolution, and the like implemented in the sequence header by inserting the MPEG sequence header processing unit 84 after the cache database 40. It is possible to easily realize an optimum coding rate / resolution change and the like taking into account the video search function of the terminal (reception side), access line type, network congestion level, processing capacity of the user terminal, and the like.

  As described above, the stream server 100 according to the present invention is configured to perform one-source multi-use by user-friendly multi-user communication using the multicast communication that is comfortable for the unspecified number of user terminals 170 by the cooperative operation of the transcoder 20 and the cache database 40. Fusion of live distribution and content distribution by building a community environment between the server and the stream server 100. In the given environment, the stream server (distribution side) can realize real-time and optimal control, and the user (reception side) ) Will be able to enjoy a more comfortable distribution service and further reduce hardware.

  FIG. 6 shows the hit / miss determination method such as the requested content (or live) and encoding method in the hit / miss determination unit 50 of the stream server 100 of the present invention in more detail. In addition, the step code | symbol shown by the figure respond | corresponds to the step code | symbol of FIG.

 [1] Hit / miss determinations (1) to (5) based on the three-stage search flow of the cache database 40 at the time of negotiation will be described below.

 (1) The hit / miss determination unit 50 searches the taggram 41 and performs hit / miss determination T1 of the requested content (or live) and the encoding method. If the request data exists (hit), the process shifts to a hit / miss determination T2 of the request encoding rate shown in FIG. 7 (see steps S110 to S130 in FIG. 4).

 (2) If the request data does not exist in the taggram 41 (miss), the hit / miss determination unit 50 searches the unstored line 43 of the taggram 42 and stores the request data in the unstored line 43 (step S140, (See S210 and S220).

 (3) In the search of the taggram 42, when there is no unstored line (miss), the hit / miss determination unit 50 searches the content line with a low audience rating, and when the target data exists (hit), The data of the low audience rating content line is discarded and the request data is stored in this line (see steps S150, S160, S210, S220).

 (4) In the search for the taggram 41, if there is no content line with a low audience rating (miss), the hit / miss determination unit 50 searches for an encoding rate line with a lower audience rating than the MRU of the taggram 42, and Is present (hit), the coding rate line data with a low audience rating is discarded, and the requested data is stored in this line (see steps S170, S210, and S220).

 (5) In the search of the taggrams 41 and 42, when there is no content with a low audience rating and an encoding rate with a low audience rating, the hit / miss determination unit 50 fails to read the target data (see step S180).

 [3] Hit / miss determinations (6) to (10) by autonomous operation of the cache database 40 when there is an unused transcoder will be described below. Due to this autonomous operation, popular content newly stored in the source database is automatically stored in the cache database. The operations (6) to (10) are the same as (1) to (5) described above.

 (6) When there is content (or live) of the requested (new) encoding method (hit), the hit / miss determination unit 50 transitions to a hit / miss determination T2 of the encoding rate shown in FIG.

 (7) If there is no request coding content (or live) (miss) and there is an unstored line, the content (or live) in the request coding method is added to the unstored line.

 (8) If there is no content (or live) in the required encoding method (miss), there is no unstored line, and there is content with a low audience rating, the content with the low audience rating is discarded, and the request encoding method Is added to the content line with a low audience rating.

 (9) If there is no content (or live) in the required encoding system (miss), there is no unstored line, no content with low audience rating, and there is an encoding rate with low audience rating, The coding rate is discarded, and the requested coding method content (or live) is added to the discarded low coding rate coding rate line.

 (10) If there is no content (or live) in the required encoding system (miss), there is no unstored line, no content with a low audience rating, and there is no encoding rate with a low audience rating, new content entry Fails.

  From (7) to (9), the new content is autonomously stored in the cache database.

  FIG. 7 shows an example of the hit / miss determination T2 of the required encoding rate in the present invention.

  This determination is redundant. That is, the difference absolute value x (the absolute value x of the difference between the encoding rate of the encoded data to be compared and the encoding rate of the request data stored in the cache database 40 currently distributed), and a predetermined value The determination differs depending on the magnitude relationship with the thresholds b and c.

  Also, the determination operation differs between the time of negotiation and the time of network monitoring (RR type RTCP packet feedback). In addition, the step code | symbol shown in the figure respond | corresponds to the step code | symbol of FIG. 4, FIG.

 [1] Hit / miss determination (1) to (5) such as a required encoding rate at the time of negotiation will be described below.

 (1) When the difference absolute value x ≦ the threshold value b, the hit / miss determination unit 50 determines that the requested encoding rate exists (hit), and the hit / miss determination T3 has redundancy in the requested encoded data. Transition to.

 (2) When the threshold value b <difference absolute value x, the hit / miss determination unit 50 determines that the requested encoding rate does not exist (miss), searches for an unstored line from the MRU of the tag 42, and stores the unstored line If there is, the request data is stored in the unstored line.

 (3) In the above-described unstored line search, if there is no unstored line (miss), the hit / miss judgment unit 50 performs a forced hit judgment on the request coding rate hit / miss judgment and performs the next request coding. Transition to data hit / miss judgment T3.

 [3] The request coding rate hit / miss determination T2 (4) to (8) during network monitoring (RR type RTCP packet feedback) will be described below.

 (4) When the difference absolute value x ≦ the threshold value b, the hit / miss determination unit 50 determines that the requested encoding rate exists (deemed hit), and transitions to the requested encoded data hit / miss determination T3. .

 (5) When threshold value b <difference absolute value x ≦ threshold value c, hit / miss determination unit 50 determines that the requested encoding rate does not exist (miss), and discards the data of the comparison target encoding rate line Thereafter, the request data is stored in this line.

 (6) When the threshold value c <the absolute difference value x, the hit / miss determination unit 50 determines that the requested encoding rate does not exist (miss), searches for an unstored line from the MRU of the tag 42, and stores the unstored line If the target data exists (hit), the request data is stored in the unstored line.

 (7) The hit / miss determination unit 50 requests if there is no unstored line in the above-described unstored line search (miss), and if there is an encoded rate line with a low audience rating in the tag 42 (hit) Store the data in the low audience rating coding rate line.

 (8) The hit / miss determination unit 50 discards the comparison encoding rate line when the unstored line and the low audience rating encoding rate line are not present (miss), and sends the requested data to this line. Store.

  The above (5) to (8) are processes when there is a transcoder to be used.

  In addition, since real-time coding rate control is performed using coded RTCP packet (RR type) feedback, autonomous coding rate control in the presence of unused transcoders (request coding rate hit / miss judgment T2) Is basically unnecessary.

  When the request encoded data hit / miss determination T3 is made, the hit / miss determination unit 50 performs the hit / miss determination T3 in the search of the cache 43. If the request data exists (hit), the hit determination is performed. If the request data does not exist (miss), the request data is stored in the target index.

  As described above, in the cache-type database 40, as shown in FIG. 2, the viewing start / stop / change of each user in the content, coding method unit, and coding rate unit is added to the MRU of the taggram 41 and the MRU of the taggram 42, respectively. By queuing the time information, it is possible to perform hit / miss determination in consideration of each user's viewing start / stop time and real-time viewing rate for data stored in the cache database.

  Also, the hit / miss determination of the cache type database 40 described above is based on normal determination trigger [1]: normal determination trigger [2]: RR type at the time of negotiation by a delivery request from a certain user terminal (reception side) There is an RTCP packet feedback time. Furthermore, hit / miss judgment is newly stored in the source database by using an operation opportunity [3] when there is an unused transcoder in addition to judgment triggers [1] and [2], and is also a cache database. It is possible to store (cache fill) popular content that is not yet stored in

  In addition, the streaming technology supports a plurality of encoding rates for a certain content, live, or encoding scheme.

  Therefore, the hit / miss determination of the cache type database 40 is performed by searching for the requested content or data corresponding to the live or encoding method (hit / miss determination T1) in response to a distribution request from the user, and then request encoding. Searching data corresponding to the rate (hit / miss determination T2), and finally searching the request data (hit / miss determination T3) makes the determination easier and faster. As well as a significant reduction in the hardware scale of the hit / miss judgment circuit.

  The hit / miss determination of the cache type database 40 is performed when the requested content or live from the user (reception side), the encoding method, the encoding rate, and the encoded data do not exist (miss). , Refer to the viewing history stored in the MRU of the taggram 42, and discard the content with low audience rating and the encoded rate line, so the content with high audience rating requested by the unspecified number of users and the code with high audience rating Only the data of the conversion rate is stored, and efficient cache operation is realized.

  The hit / miss judgment of the cache type database is based on the currently used code for the optimum requested coding rate considering the congestion degree of the network and user terminal processing capacity based on feedback information by RR type RTCP packet. When the absolute value of the difference from the conversion rate is equal to or less than a predetermined threshold, the hit / miss determination with redundancy is performed, so that it does not follow a real-time network congestion level and a sudden change in user terminal processing capability.

  In addition, even when the data stored in the cache type database is all high audience rating data, for example, if the data stored in the cache database is equal to or greater than the predetermined threshold, by performing forced hit determination, Does not affect.

  By the above operation, the stream server of the present invention can realize the distribution request data of its own by autonomous operation and the distribution data to other user terminals.

  8 and 9 show an example of the layered encoding method in the stream server 100 of the present invention. This hierarchical coding is hierarchized by spatial scalability, temporal scalability, SNR (Signal to Noise Ratio) scalability, etc., and when changing the coding rate of a certain layer, the layer for which the coding rate is changed and this layer New encoded data is created only for the encoded data of the next higher level.

  FIG. 8 shows a case where the low coding rate is changed to the high coding rate. In FIG. 1 (1), the coding rates of the layers 1, 2, 3, and 4 are 1 Mbps, 5 Mbps, 10 Mbps, and 20 Mbps, respectively.

  FIG. 4 (4) shows a bank 90 in which the coding rates of the respective layers 1 to 4 shown in FIG. 1 (1) are stored. The banks 90_1 to 90_4 each have a coding rate of 1 Mbps, 5Mbps, 10Mbps, and 20Mbps data are stored.

  When changing the coding rate of layer 2 from 5 Mbps (low coding rate) to 7 Mbps (high coding rate) in (2) and (5) in the figure, new layer 2 new coded data and this new layer New encoded data of the new layer 3 (10 Mbps) that performs the decompression operation with reference to 2 is stored in the banks 90_5 and 90_6, respectively.

  In (3) and (6) in the figure, when the sum of absolute differences between the decoded frame data expanded from the new layer 3 and the decoded frame data expanded from the current layer 3 is below a certain threshold, Hierarchies 2 and 3 (banks 90_2 and 90_3) are discarded, and new hierarchies 2 and 3 (banks 90_5 and 90_6) are made current hierarchies 2 and 3, and a new hierarchical structure is switched.

  FIG. 9 shows a case where the high encoding rate is changed to the low encoding rate. FIGS. (1) and (4) are the same as FIGS. 8 (1) and (4), respectively.

  9 (2) and (5), when the encoding rate of layer 3 is changed from 10 Mbps (high encoding rate) to 7 Mbps (low encoding rate), new layer 3 (7 Mbps) and this new layer 3 The new encoded data of the new hierarchy 4 (20 Mbps) that performs the decompression operation with reference to is stored in the banks 90_5 and 90_6.

  In (3) and (6) in the figure, when the sum of absolute differences between the decoded frame data decompressed from the new layer 4 and the decoded frame data decompressed from the current layer 4 falls below a certain threshold, Hierarchies 3 and 4 (banks 90_3 and 90_4) are discarded, and new hierarchies 3 and 4 (banks 90_5 and 90_6) are made current hierarchies 2 and 3, and the new hierarchies are switched.

  That is, when changing the coding rate of a certain layer in the above-mentioned layered coding, this layer data is used as reference data, without changing the data of all the subsequent upper layers, one higher layer. By changing only the hierarchical data, it is possible to change the encoding rate and construct a new hierarchical structure.

  In this coding rate change, the required number of banks can be realized only by the number of layers +2, and the hardware scale can be reduced.

As described above, according to the stream server of the present invention, to an indefinite number user terminal given environment respectively, i.e., network load, the user terminal processing capacity, or the degree of congestion of the stream server It is possible to realize content distribution corresponding to real time and to integrate content distribution and live distribution with less hardware.

It is the block diagram which showed one Example of the stream server which concerns on this invention. It is the block diagram which showed one structural example of the cache type database in the stream server which concerns on this invention. It is the figure which showed the example of the 3 steps | paragraph search procedure in the stream server which concerns on this invention. It is the flowchart figure which showed the operation | movement procedure at the time of the negotiation of the stream server concerning this invention. It is the flowchart figure which showed the operation | movement procedure at the time of the network monitoring of the stream server which concerns on this invention. It is the figure which showed hit / miss determination, such as a request | requirement content (or live) and an encoding system, and its subsequent process in the stream server which concerns on this invention. It is the figure which showed hit / miss determination, such as a request | requirement encoding rate in the stream server based on this invention, and its subsequent process. It is the figure which showed the encoding rate change example (low encoding rate-> high encoding rate) in the hierarchical encoding in the stream server which concerns on this invention. It is the figure which showed the encoding rate change method (high encoding rate-> low encoding rate) in the hierarchical encoding in the stream server which concerns on this invention. It is the block diagram which showed the conventional content delivery and live delivery.

Explanation of symbols

100 Stream server 10 Transcoder control / arbiter
20, 20_1 ~ 20_L transcoder, encoder, CODEC
30 Database control / arbiter 40 Cache type database
41,41_1 ～ 41_M Tagagram (TAG_RAM) 41a Viewing history (MRU)
41b Contents (Contents) 41c Coding method (COD)
41d Tagram address (TAG_RAM_Adr) 42, 42_1 to 42_N Tagram
42a Viewing history (MRU) 42b Coding rate (Rate)
42c Layer 43 cache
43_1 ~ 43_N LINE 43a Index
50 Hit / miss judgment unit 60 Network monitoring unit
70 Call control / negotiation processor 80 Protocol implementation processor
81 IP header processor 82 UDP header processor
83 RTP header processor 84 MPEG sequence header processor
85 RTCP header processor 86 RTSP header processor
90, 90_1-90_6 banks
110 Content server 120 Video input device
130 Real-time encoder 140 IP network
150_1, 150_2 Cache server 160 Terminal adapter (TA)
170 User terminal
170_1 User terminal (desktop PC)
170_2 User terminal (PDA) 170_3 User terminal (mobile phone)
700 source database
710, 710_1 to 710_3, 720_1, 720_2 content
710a Content Delivery 720 Live
720a, 720b live streaming
800 Transcoder entry request signal 801 signal
802 data
a, b, c Threshold x Difference absolute value
01-0x, 11-1x, 21-2x, y1-yx Viewing history
T1-T3 hit / miss determination In the figure, the same reference numerals indicate the same or corresponding parts.

Claims (3)

One or more transcoders;
A cache database that stores data;
When the requested data regarding content or live, encoding scheme, and encoding rate is not stored in the cache type database, the transcoder and the A hit / miss determination unit that controls a cache-type database in cooperation,
With
The hit / miss determination unit further searches for the encoding rate closest to the requested encoding rate from among the encoding rates corresponding to the requested content or live and encoding scheme, and the requested encoding when the difference absolute value of the nearest coding rate to the rate and retrieved request is below a predetermined threshold value, the stream server to which the request data is characterized in that it is determined that that is stored in the cache database. In claim 1,
And a network monitoring unit that monitors at least one of a network load with the user terminal, a congestion level of the content server, or a processing capability of the user terminal, and gives a monitoring result to the hit / miss determination unit. ,
A stream server, wherein the hit / miss determination unit determines an optimum encoding rate based on the monitoring result. One or more transcoders;
A cache database that stores data;
When the requested data regarding content or live, encoding scheme, and encoding rate is not stored in the cache type database, the transcoder and the A hit / miss determination unit that controls a cache-type database in cooperation,
With
In the hierarchical coding based on spatial scalability, temporal scalability, or SNR scalability, the transcoder newly creates only the coding data of the coding rate change target layer and the layer one level above it, and is expanded from the new higher layer. A stream that has the newly created change target layer and upper layer as the current layer when the sum of absolute differences between the decoded data and the decoded data expanded from the current upper layer is equal to or less than a predetermined threshold value. server.

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