JP2005123942A - Receiver, method and program for managing cache, and medium recording program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data receiver caching more data required by a user even in an environment of limited memory amount and capable of shortening the waiting time of a user when the data screen makes a transition. <P>SOLUTION: The receiver comprises a data reproducing section, a TS receiving section, a TS separating section, a video/audio decoding section, applications such as EPG or still image display application and menu application, a user input receiving section, and an output section. The data reproducing section comprises a data cache section receiving a state change notice, e.g. end of starting application, to release a cache of such memory amount as being used by that application when it is started and to secure the cache of that memory amount again when the application is ended, thus caching the data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a receiving apparatus that receives data sent from a network, and more particularly to a cache control technique for transmitted data.

Data broadcasting that is broadcast by digital broadcasting or the like is realized by repeatedly broadcasting the same data. A set of data to be repeatedly broadcast is called a data carousel, and a method for sending a data carousel is called a data carousel sending method.
In this method, since the same data is repeatedly transmitted in a cycle of several seconds to several tens of seconds, the necessary data can be always received regardless of when the viewer requests to view the data. However, when a large amount of data is transmitted in the same transmission band, the data carousel cycle becomes long, and this data reception waiting time greatly affects the screen switching response.

  Therefore, generally, a method of caching data acquired once or pre-reading and caching is taken. However, the capacity of the built-in memory of the receiver is finite, and it is impossible to hold all transmitted data. Therefore, a contrivance has been made to improve the probability that the data requested by the user exists in the cache, that is, the cache hit rate.

In the invention of Patent Document 1, a method of preferentially erasing data having a close sending time from the cache based on the sending situation of each data examined in advance is proposed.
As another approach, in the invention of Patent Document 2, an apparent cache size is expanded by compressing and caching data to improve a cache hit rate.
JP 2001-326581 A JP 2003-32630 A

In the first place, when the size of data to be transmitted is larger than the size of the cache area, there is data that cannot be cached, and the user waits for a long time to acquire this data. The invention described in Patent Document 1 cannot solve this problem.
Further, in the invention described in Patent Document 1, there is a case where a sufficient cache effect cannot be expected when the transmission timings of a plurality of data necessary for data screen display for one screen are different from each other.

In the current data broadcasting, data is compressed and sent on the transmission side. In the case of the invention described in Patent Document 2, the expansion and recompression of the still image included in the data, Compression processing is required, leading to a reduction in the data processing capability of the receiving apparatus, and as a result, affecting the waiting time of the user.
The present invention has been made in view of these problems. In the receiving apparatus, the cache hit rate is improved by securing a larger data cache area, and the waiting time for switching the data screen of the user is reduced. With the goal.

  In order to achieve the above-described object, a receiving apparatus of the present invention includes a receiving unit that receives data from a network, a cache unit that caches data received by the receiving unit, and an application that receives notification of the status of another application. A state receiving means, and a cache size determining means for determining a total size of data that can be cached by the cache means in response to a notification from the application state receiving means, while the other application is not activated By securing a limited amount of memory, more data is cached, the memory used by that application is released when another application starts, and the cached data is deleted as necessary. By leaving data with a high probability required by , Characterized in that to minimize the reduction of the cache hit rate.

As described above, according to the present invention, the maximum memory can be secured while other applications are not operating, so there is no need to discard the cache. It is possible to improve and shorten the data screen switching time by the cache.
In addition, since the present invention makes it possible to secure a large cache area, processing for compressing and decompressing data is not required, and performance degradation and data screen switching time due to data compression and decompression processing in the invention described in Patent Document 2 are eliminated. There is no increase.

  Also, when other applications are activated, data that is highly likely to be viewed by the user is retained, so that it is possible to minimize a decrease in the cache effect due to a reduction in cache memory.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
The embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a receiving device 100 according to one embodiment of the present invention.
In FIG. 1, a receiving apparatus 100 includes a data reproducing unit 300, a TS receiving unit 110, a TS separating unit 120, a video / audio decoding unit 130, an application 140 such as an EPG or a still image display application and a menu application, a user input receiving unit 150, And an output unit 160.

  The application 140 is activated or terminated by a remote control operation or the like by the user, generates a program guide, a still image, and an image for displaying a screen for setting the receiving device 100 and outputs the generated image to the output unit 160. For example, there are an EPG (Electric Program Guide) for displaying a program guide, a still image viewer for displaying a still image recorded on a memory card attached to a receiving device, a menu application for setting a receiver, and the like.

  When the application 140 is started, terminated, or when the memory size required by the application is changed, the application 140 changes the amount of change in the memory size of the application (hereinafter referred to as memory) to the application communication unit 340 of the data reproduction unit 300. Called a size change amount). For example, when starting up, the memory size required by the application itself is notified, and when ending, the memory size used by the application itself at that time is notified. When changing the memory size, the memory size to be changed is notified. For example, when the memory size change amount is 1 megabyte, it means that the application needs 1 megabyte for the application to operate. Further, if the memory size change amount is minus 1 megabyte, it means that the own application no longer needs 1 megabyte of memory.

The user input receiving unit 150 receives an input signal by a remote control operation or the like from the user and outputs the signal to the data interpretation display unit 350 and the application 140 of the data reproducing unit 300.
The receiving unit 302 receives MPEG2-TS (Transport Stream) in which a video signal, an audio signal, and data are multiplexed. MPEG2-TS is defined by ISO / IEC13818-1 MPEG2 SYSTEMS.

The TS separation unit 120 separates the MPEG2-TS received by the reception unit 302 into a video signal, an audio signal, and a data signal.
The video / audio decoding unit 130 decodes the video signal and the audio signal separated by the TS separation unit 120, and outputs them to the output unit 160.
The output unit 160 superimposes the video signal from the video / audio decoding unit 130 on the display image from the data interpretation display unit 350 and the application 140 and outputs the superimposed image together with the audio signal from the video / audio decoding unit 130.

(Detailed description of the data reproducing unit 300)
The data reproducing unit 300 includes a data receiving unit 310, a data cache unit 320, a cache storage unit 330, an application communication unit 340, and a data interpretation display unit 350.
The data signal is separated from the MPEG2-TS received by the TS separator 120 and sent to the data receiver 310. The TS separation unit 120 is realized by a tuner and a transport decoder that receive MPEG2-TS, but is not limited thereto.

The data receiving unit 310 extracts the data module from the data stream and sends it to the data cache unit 320. Here, the data module is a unit of data defined by ISO / IEC13818-6 DSMCC (Digital Storage Media Command and Control).
The data cache unit 320 confirms whether the sent data module exists in the cache storage unit 330, and if it does not exist, accumulates it in the cache storage unit 330. The data cache unit 320 holds a cache list 400, a cache upper limit value (not shown), and a cache size value (not shown), and when the sum of the size of the sent data module and the cache size value exceeds the cache upper limit value, Based on the cache list 400, unnecessary cached data is deleted or the sent data module is deleted and the cache list 400 is updated. The data cache unit 320 changes the cache size upper limit value based on the command received from the application communication unit APC, and when the cache size value exceeds the cache upper limit value, an unnecessary cached data is stored based on the cache list 400. The data is deleted and the cache list 400 is updated.

  The data cache unit 320 reads data from the cache storage unit 330 according to the data module acquisition request from the data interpretation display unit 350 and outputs the data to the data interpretation display unit 350. At this time, the data cache unit 320 increments the value of the reference count of the module in the cache list 400 for the data module that has received the acquisition request.

The cache storage unit 330 stores data cached by the data cache unit 320. Although it is configured by a recording medium capable of reading and writing data such as a semiconductor memory, a nonvolatile memory, a hard disk, and a DVD, the type is not particularly limited.
The data interpretation display unit 350 receives a remote control input signal from the user input reception unit 150, interprets and executes the data according to the signal content, and makes a display image switching or new data acquisition request. The data interpretation display unit 350 acquires a data module from the data cache unit 320 or the data reception unit 310 when a new data acquisition request is generated, interprets the data, creates a display image, and inputs it to the output unit 160 To do.

The application communication unit 340 communicates with the application 140 (EPG, a still image display application, a menu application, etc.) and receives a notification of a change in the memory size used by the application from the application 140.
(Description of cache list 400)
Hereinafter, the cache list 400 will be described with reference to FIG. The cache list 400 is a list that describes a list of data modules that have been cached in the cache storage unit 330.

  In FIG. 2, Module_id is an ID for identifying a data module, and Module_Version is a number for identifying the version of the data module. Module_Size indicates the size of the data module. The reception date / time indicates the date / time when the data module is received and cached. The reference count indicates the number of times that the data module has received a read request from the data interpretation display unit 350.

  In the example of FIG. 2, the data module with Module_id = 0000 has a version of 1, a size of 1000 KB, and a received and cached date / time of December 7, 2001, 6:00: 00, and received a read request. The number of times is 100 times. Similarly, a data module with Module_id = 0001 has a version of 1, a size of 100 KB, a reception date and time of December 7, 2001, 7:33:22, and the number of read requests received is 50. Indicates.

(Processing flow of the data cache unit 320 when the received data is cached)
Hereinafter, the processing flow of the data cache unit 320 will be described in detail with reference to the drawings.
FIG. 3 is a diagram illustrating a processing flow of the data cache unit 320 when the receiving device 100 receives data and caches the data.
First, the data cache unit 320 receives the data module received by the data receiving unit 310 (S1000).

The data cache unit 320 searches the cache list 400 with Module_id of the data module (S1001). The data cache unit 320 checks whether the data module has been cached (S1002).
If the data module is not cached, the data cache unit 320 checks the size of the received data module and calculates the sum of the size and the cache size value (hereinafter referred to as the cache size total value). (S1003). The data cache unit 320 compares the cache size total value with the cache upper limit value (S1004). When the cache size total value is equal to or less than the cache upper limit value, the data cache unit 320 accumulates the data module in the cache storage unit 330, and checks the module_id, Module_Version, Module_Size, reception date and time, and reference count of the data module. It adds to the list 400 (S1005), and updates the cache size total value to the cache size value (S1006).

  If the data module has been cached in S1002, the data cache unit 320 compares Module_Version of the data module with the data module described in the cache list 400 (S1007). When the Module_Version is different, the information on the same data module described in the cache list 400 is deleted, and the module is deleted from the cache storage unit 330 (S1008). The data cache unit 330 subtracts the size of the module from the cache size value (S1009), and goes to S1003. If the Module_Version is the same in S1007, the received data module is discarded (S1010).

  In S1004, when the total cache size value exceeds the cache upper limit value, the data cache 320 unit searches the cache list 400 for the data module with the smallest reference count (S1011), and deletes the data module from the cache storage unit 330. The information about the data module is deleted from the cache list 400 (S1012), and the size of the data module is subtracted from the cache size value (S1013). Then, S1003 to S1013 are repeated until the cache size total value falls below the cache upper limit value and the received data module can be cached.

(Processing flow of the data cache unit 320 when the application communication unit 340 receives a notification from the application 140)
Hereinafter, the processing flow of the data cache unit 320 when the application communication unit 340 receives a notification from the application 140 will be described in detail with reference to the drawings.
FIG. 4 shows a processing flow in which the data cache unit 320 controls the cache data in the cache storage unit 330 according to the contents after the application communication unit 340 receives the notification from the application 140.

First, when a change occurs in the memory size to be used due to the activation, termination, or state change of the application 140, the application 140 notifies the application communication unit 340 of the amount of change in the memory size to be used (S1500).
The application communication unit 340 notifies the data cache unit 320 of the received memory size change amount (S1501).

  The data cache unit 320 subtracts the received memory size change amount from the cache upper limit value (S1502). For example, if the cache upper limit value is 8 megabytes and the memory size change amount is 1 megabyte, that is, the application 140 requires 1 megabyte, the cache upper limit value is 8-1 = 7 megabytes. Similarly, when the memory size change amount is minus 1 megabyte, the cache upper limit value is 8-(− 1) = 9 megabytes.

The data cache unit 320 compares the cache upper limit value calculated in S1502 with the cache size value (S1503).
The data cache unit 320 does nothing if the cache size value is less than or equal to the cache upper limit value.
If the cache size value exceeds the cache upper limit value in S1503, the data cache unit 320 searches for the data module with the smallest reference count in the cache list 400 (S1504), and stores the data module in the cache storage. The module information is deleted from the unit 330, and the module information is deleted from the cache list 400 (S1505). The data cache unit 320 subtracts the size of the data module from the cache size value (S1506). Then, S1503 to S1506 are repeated until the cache size value falls below the cache upper limit value and the received data module becomes cacheable.

  As described above, the maximum memory can be used as a cache while other applications are not running, and more data can be cached, improving the cache hit rate and switching the data display. Time can be shortened. In addition, since compression processing is unnecessary when caching, compression / decompression processing for data reproduction is not necessary, and performance and data display switching time are not shortened.

  In addition, when other applications are activated, it is possible to prevent memory shortage in the entire receiving apparatus by releasing the memory necessary for the applications. In addition, when the memory is released, data with a low reference count is deleted, and data with a high reference count and high priority for the user is retained in the cache, reducing the cache effect by reducing the cache capacity. It can be minimized.

The network in this embodiment includes not only communication but also broadcasting.
In this embodiment, MPEG2-TS is received, but is not limited to MPEG2-TS, a data request is issued to the server, and data transmitted from the server is received in response to the request. Also good. In this case, the data cache unit may measure the time from when a request is sent to the server until the data is received and cached, and the time may be stored together with the data module. In addition, when the size of the cached data held by the data playback unit exceeds the cache upper limit, the data cache unit gives priority to data that has a short time from when a request is sent to the server until data is received and cached. It may be deleted. The data cache unit calculates and stores a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and sets a cycle in the reception date and time as a condition for determining data to be deleted from the cache storage unit. The shorter data may be deleted preferentially by the difference between the added date and time and the current date and time from when the request is sent to the server until the data is received and cached. The shorter data may be deleted preferentially in terms of the time from when the request is issued until the data is received and cached.

In this embodiment, the number of references is used as a condition for the data cache unit to determine data to be deleted from the cache storage unit. However, the oldest received date may be deleted, and the data size may be You may make it delete the largest thing.
The data cache unit may calculate a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and store the calculated cycle in the cache storage unit. At this time, as a condition for determining data to be deleted from the cache storage unit, the data cache unit may preferentially delete the date / time obtained by adding the period to the reception date / time and the data module that will be received earliest from the current date / time. However, the data module having the shortest cycle may be deleted preferentially.

  In the present embodiment, it is described that there is one data reproducing unit for the receiving device, but a plurality of data reproducing units may be present. A single cache storage unit is used for a plurality of data reproduction units, and the cache storage unit stores data cached by the plurality of data reproduction units, and each data reproduction unit has a cache size upper limit. Values and cache lists may be maintained.

  At this time, not only the application but also the data reproduction unit notifies the application communication unit of the other data reproduction unit of the memory size change amount, and according to the memory size change amount, the cache size upper limit of the notified data reproduction unit The value may be changed. When the amount of data cached by each data playback unit exceeds the cache size upper limit, the data deleted by each data cache unit may be the one with the smallest number of references or the one with the oldest reception date and time. As a condition for determining the data to be deleted from the cache storage unit by calculating and storing a cycle in which the data module is repeatedly transmitted from the time when the same data module is received. The date / time obtained by adding the cycle to the reception date / time and the data module that will be received earliest from the current date / time may be deleted preferentially, or the data module having the shortest cycle may be deleted preferentially. Good.

Further, among the plurality of data reproduction units, only one data reproduction unit may be enabled at the same time, and only the reproduction content may be displayed on the screen to accept input from the user input unit.
In this case, when the amount of data cached by each data reproduction unit exceeds the cache size upper limit value, the cached data of the data reproduction unit that is not in the valid state may be deleted preferentially, or each data reproduction unit May hold the time when the cache storage unit was last accessed and preferentially delete the cached data stored by the data reproducing unit with the oldest time. Further, a data request may be issued to the server, and data transmitted from the server in response to the request may be received. In this case, the data cache unit may measure the time from when a request is sent to the server until the data is received and cached, and the time may be stored together with the data module.

  In addition, when the size of the cached data held by the data playback unit exceeds the cache upper limit, the data cache unit gives priority to data that has a short time from when a request is sent to the server until data is received and cached. It may be deleted. The data cache unit calculates and stores a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and sets a cycle in the reception date and time as a condition for determining data to be deleted from the cache storage unit. The shorter data may be deleted preferentially by the difference between the added date and time and the current date and time from when the request is sent to the server until the data is received and cached. The shorter data may be deleted preferentially in terms of the time from when the request is issued until the data is received and cached.

Note that there are a plurality of data reproducing units for the receiving device, the data cache unit and the cache storage unit are shared, and the data cached by the plurality of data reproducing units is stored in the cache storage unit. The cache unit may hold the cache size upper limit value and the cache list of the plurality of data reproducing units as a whole.
At this time, the memory size change amount may be notified from the application, and the data cache unit may change the cache size upper limit value according to the memory size change amount. In this case, when the total amount of data cached by each data reproduction unit exceeds the cache size upper limit value, the data to be deleted by the data cache unit may be the one with the smallest number of references or the reception date and time is the most. Data that is old, may have the largest data size, or is calculated and stored from the time when the same data module is received is repeatedly stored and deleted from the cache storage unit The data module that receives the earliest from the date and time obtained by adding the period to the reception date and time and the current date and time may be deleted preferentially, or the data module that has the shortest period may be deleted preferentially. You may make it do.

  Further, among the plurality of data reproduction units, only one data reproduction unit may be enabled at the same time, and only the reproduction content may be displayed on the screen to accept input from the user input unit. In this case, if the total amount of data cached by each data playback unit exceeds the cache size upper limit value, the data cache unit may preferentially delete the cached data of the data playback unit that is not in the valid state. Alternatively, the time when each data reproducing unit last accessed the cache storage unit may be held, and the cached data stored by the data reproducing unit with the oldest time may be deleted preferentially. Further, a data request may be issued to the server, and data transmitted from the server in response to the request may be received.

  In this case, the data cache unit may measure the time from when a request is sent to the server until the data is received and cached, and the time may be stored together with the data module. In addition, when the size of the cached data held by the data playback unit exceeds the cache upper limit, the data cache unit gives priority to data that has a short time from when a request is sent to the server until data is received and cached. It may be deleted. The data cache unit calculates and stores a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and sets a cycle in the reception date and time as a condition for determining data to be deleted from the cache storage unit. The shorter data may be deleted preferentially by the difference between the added date and time and the current date and time from when the request is sent to the server until the data is received and cached. The shorter data may be deleted preferentially in terms of the time from when the request is issued until the data is received and cached.

(Embodiment 2)
FIG. 5 is a block diagram showing a second embodiment of the receiving apparatus according to the present invention.
In FIG. 5, the receiving device 2000 includes a data reproducing unit 2300, a TS receiving unit 2010, a TS separating unit 2020, a video / audio decoding unit 2030, an application 2040 such as an EPG or a still image display application and a menu application, a user input receiving unit 2050, And an output unit 2060.

Among these, the TS reception unit 2010, the TS separation unit 2020, the video / audio decoding unit 2030, the user input unit 2050, and the output unit 2060 are the same as those in the first embodiment, and thus description thereof is omitted.
The application 2040 is activated or terminated by a remote control operation or the like by the user, generates a program guide, a still image, and an image for displaying a screen for setting the receiving device 2000, and outputs the generated image to the output unit 2060. For example, there are an EPG (Electric Program Guide) for displaying a program guide, a still image viewer for displaying a still image recorded on a memory card attached to a receiving device, a menu application for setting a receiver, and the like.

The application 2040 notifies the application communication unit 2340 of the data reproduction unit 2300 of an ID for identifying the application (hereinafter referred to as an application ID) and an activation state of the application (whether it is activated or terminated) at the time of activation and termination. To do.
(Detailed Description of Data Reproducing Unit 2300)
The data reproducing unit 2300 includes a data receiving unit 2310, a data cache unit 2320, a cache storage unit 2330, an application communication unit 2340, and a data interpretation display unit 2350.

The data receiving unit 2310 receives not only the data module but also the memory usage list 2500 and sends it to the data cache unit 2320.
Since the cache storage unit 2330 and the data interpretation display unit 2350 are the same as those in the first embodiment, description thereof is omitted.
The data cache unit 2320 confirms whether the transmitted data module exists in the cache storage unit 2330, and if it does not exist, accumulates it in the cache storage unit 2330. The data cache unit 2320 holds a cache list 2400, a cache upper limit value (not shown), a cache size value (not shown), and a memory usage list 2500.

  When the sum of the size of the sent data module and the cache size value exceeds the cache upper limit value, the data cache unit 2320 deletes unnecessary cached data based on the cache list 2400 or sends the sent data module And the cache list 2400 is updated. The data cache unit 2320 searches the memory usage list 2500 based on the application ID received from the application communication unit APC and the activation state of the application, and sets the cache size upper limit value according to the memory amount described in the memory usage list 2500. If the cache size value exceeds the cache upper limit value, unnecessary cached data is deleted based on the cache list 2400 and the cache list 2400 is updated.

  The data cache unit 2320 reads data from the cache storage unit 2330 in accordance with the data module acquisition request from the data interpretation display unit 350 and outputs the data to the data interpretation display unit 2350. At this time, the data cache unit 2320 increments the value of the reference count of the module in the cache list 2400 for the data module that has received the acquisition request.

The data cache unit 2320 receives the memory usage list 2500 received by the data receiving unit 2310 and replaces it with the already used memory usage list.
Since the cache list 2400 is the same as that of the first embodiment, description thereof is omitted.
The application communication unit 2340 communicates with the application 2040 (EPG, still image display application, menu application, etc.), and notifies the application 2040 of an ID for identifying the application and the state of the application (started or finished). receive.

(Description of memory usage list 2500)
The figure shows an example of the memory usage list 2500. The memory usage list 2500 is a list of memory amounts necessary for each application to operate. For example, in the figure, it is shown that the amount of memory necessary for an application with an application ID of 1 to operate is 1 MB. The same applies to applications with other application IDs. Similarly, for an application with an application ID of 2, the memory usage is 0.5 MB.

Since the processing flow of the data cache unit 2320 when the received data is cached is the same as that of the first embodiment, description thereof is omitted.
(Processing flow of the data cache unit 2320 when the application communication unit 2340 receives a notification from the application 2040)
Hereinafter, in the present embodiment, a processing flow of the data cache unit 2320 when the application communication unit 2340 receives a notification from the application 2040 will be described in detail with reference to the drawings.

FIG. 7 shows a processing flow in which the data communication unit 2320 controls the cache data in the cache storage unit 2330 according to the contents after the application communication unit 2340 receives the notification from the application 2040.
First, when the application 2040 is activated or terminated, the application communication unit 2340 is notified of its own application ID and activation status (whether it is activated or terminated) (S3000).

The application communication unit 2340 notifies the received application ID and activation state to the data cache unit 2320 (S3001).
The data cache unit 2320 searches the memory usage list 2500 for the memory usage of the application with the application ID (S3002).
The data cache unit 2320 determines whether the activation state received from the application communication unit 2340 is activation or termination (S3003).

When the activation state received from the application communication unit 2340 is the end, the data cache unit 2320 adds the memory usage searched in S3002 to the cache size upper limit value (S3004).
Hereinafter, processing of the data cache unit 2320 when the activation state received from the application communication unit 2340 is activation will be described.

The data cache unit 2320 calculates a new cache upper limit value by subtracting the memory use amount searched in S3002 from the cache upper limit value (S3005).
The data cache unit 2320 compares the cache upper limit value calculated in S3005 with the cache size value (S3006).
The data cache unit 2320 does nothing if the cache size value is less than or equal to the cache upper limit value.

  If the cache size value exceeds the cache upper limit value in S3006, the data cache unit 2320 searches for the data module with the smallest reference count in the cache list 400 (S3007), and stores the data module in the cache storage. The module information is deleted from the part 2330, the module information is deleted from the cache list 2400 (S3008), and the size of the data module is subtracted from the cache size value (S3009). Then, S3006 to S3009 are repeated until the cache size value falls below the cache upper limit value and the received data module can be cached.

  As described above, the maximum memory can be used as a cache while other applications are not running, and more data can be cached, improving the cache hit rate and switching the data display. Time can be shortened. In addition, since compression processing is unnecessary when caching, compression / decompression processing for data reproduction is not necessary, and performance and data display switching time are not shortened.

  In addition, when other applications are activated, it is possible to prevent memory shortage in the entire receiving apparatus by releasing the memory necessary for the applications. In addition, when the memory is released, data with a low reference count is deleted, and data with a high reference count and high priority for the user is retained in the cache, reducing the cache effect by reducing the cache capacity. It can be minimized.

The data receiving unit 2310 may receive the memory usage list, and the data cache unit may replace the memory usage list.
The network in this embodiment includes not only communication but also broadcasting.
In this embodiment, MPEG2-TS is received, but is not limited to MPEG2-TS, a data request is issued to the server, and data transmitted from the server is received in response to the request. Also good.

  In this case, the data cache unit may measure the time from when a request is sent to the server until the data is received and cached, and the time may be stored together with the data module. In addition, when the size of the cached data held by the data playback unit exceeds the cache upper limit, the data cache unit gives priority to data that has a short time from when a request is sent to the server until data is received and cached. It may be deleted. The data cache unit calculates and stores a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and sets a cycle in the reception date and time as a condition for determining data to be deleted from the cache storage unit. The shorter data may be deleted preferentially by the difference between the added date and time and the current date and time from when the request is sent to the server until the data is received and cached. The shorter data may be deleted preferentially in terms of the time from when the request is issued until the data is received and cached.

In this embodiment, the number of references is used as a condition for the data cache unit to determine data to be deleted from the cache storage unit. However, the oldest received date may be deleted, and the data size may be You may make it delete the largest thing.
The data cache unit may calculate a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and store the calculated cycle in the cache storage unit. At this time, as a condition for determining data to be deleted from the cache storage unit, the data cache unit may preferentially delete the date / time obtained by adding the period to the reception date / time and the data module that will be received earliest from the current date / time. However, the data module having the shortest cycle may be deleted preferentially.

  In the present embodiment, it is described that there is one data reproducing unit for the receiving device, but a plurality of data reproducing units may be present. A single cache storage unit is used for a plurality of data reproduction units, and the cache storage unit stores data cached by the plurality of data reproduction units, and each data reproduction unit has a cache size upper limit. Values, cache lists, and memory usage lists may be maintained.

  At this time, not only the application but also the data reproducing unit notifies the application communication unit of the other data reproducing unit of the ID including the data reproducing unit and the activation state, and uses the memory according to the ID and the activation state. The amount list may be searched to check the memory usage of the application or the data reproduction unit, and the cache size upper limit value of the data reproduction unit that has received the notification may be changed based on this value. When the amount of data cached by each data playback unit exceeds the cache size upper limit, the data deleted by each data cache unit may be the one with the smallest number of references or the one with the oldest reception date and time. As a condition for determining the data to be deleted from the cache storage unit by calculating and storing a cycle in which the data module is repeatedly transmitted from the time when the same data module is received. The date / time obtained by adding the cycle to the reception date / time and the data module that will be received earliest from the current date / time may be deleted preferentially, or the data module having the shortest cycle may be deleted preferentially. Good. Further, among the plurality of data reproduction units, only one data reproduction unit may be enabled at the same time, and only the reproduction content may be displayed on the screen to accept input from the user input unit. In this case, when the amount of data cached by each data reproduction unit exceeds the cache size upper limit value, the cached data of the data reproduction unit that is not in the valid state may be deleted preferentially, or each data reproduction unit May hold the time when the cache storage unit was last accessed and preferentially delete the cached data stored by the data reproducing unit with the oldest time.

  Further, a data request may be issued to the server, and data transmitted from the server in response to the request may be received. In this case, the data cache unit may measure the time from when a request is sent to the server until the data is received and cached, and the time may be stored together with the data module. In addition, when the size of the cached data held by the data playback unit exceeds the cache upper limit, the data cache unit gives priority to data that has a short time from when a request is sent to the server until data is received and cached. It may be deleted. The data cache unit calculates and stores a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and sets a cycle in the reception date and time as a condition for determining data to be deleted from the cache storage unit. The shorter data may be deleted preferentially by the difference between the added date and time and the current date and time from when the request is sent to the server until the data is received and cached. The shorter data may be deleted preferentially in terms of the time from when the request is issued until the data is received and cached.

Note that there are a plurality of data reproducing units for the receiving device, the data cache unit and the cache storage unit are shared, and the data cached by the plurality of data reproducing units is stored in the cache storage unit. The cache unit may hold the cache size upper limit value, the cache list, and the memory usage list of the plurality of data reproducing units as a whole.
At this time, the application notifies the application communication unit of the data reproduction unit of the ID for identifying the application and the activation state, and searches the memory usage list according to the ID and the activation state to check the memory usage of the application. Based on this value, the data cache unit may change the cache size upper limit value. In this case, when the total amount of data cached by each data reproduction unit exceeds the cache size upper limit value, the data to be deleted by the data cache unit may be the one with the smallest number of references or the reception date and time is the most. Data that is old, may have the largest data size, or is calculated and stored from the time when the same data module is received is repeatedly stored and deleted from the cache storage unit The data module that receives the earliest from the date and time obtained by adding the period to the reception date and time and the current date and time may be deleted preferentially, or the data module that has the shortest period may be deleted preferentially. You may make it do.

  Further, among the plurality of data reproduction units, only one data reproduction unit may be enabled at the same time, and only the reproduction content may be displayed on the screen to accept input from the user input unit. In this case, if the total amount of data cached by each data playback unit exceeds the cache size upper limit value, the data cache unit may preferentially delete the cached data of the data playback unit that is not in the valid state. Alternatively, the time when each data reproducing unit last accessed the cache storage unit may be held, and the cached data stored by the data reproducing unit with the oldest time may be deleted preferentially.

Further, a data request may be issued to the server, and data transmitted from the server in response to the request may be received. In this case, the data cache unit may measure the time from when a request is sent to the server until the data is received and cached, and the time may be stored together with the data module.
In addition, when the size of the cached data held by the data playback unit exceeds the cache upper limit, the data cache unit gives priority to data that has a short time from when a request is sent to the server until data is received and cached. It may be deleted. The data cache unit calculates and stores a cycle in which the data module is repeatedly transmitted from the time when the same data module is received, and sets a cycle in the reception date and time as a condition for determining data to be deleted from the cache storage unit. The shorter data may be deleted preferentially by the difference between the added date and time and the current date and time from when the request is sent to the server until the data is received and cached. The shorter data may be deleted preferentially in terms of the time from when the request is issued until the data is received and cached.

  In addition, although the block diagram of each said embodiment was shown in FIG. 1, FIG. 5, you may make it describe with the program which makes a computer exhibit the function of each component. Furthermore, this program may be recorded on a computer-readable recording medium, and this recording medium may be applied to a file reading device.

  The receiving device according to the present invention has a function of dynamically controlling the cache upper limit value in the data cache unit according to the memory usage status of the application, and is applied to all receiving devices having a function of receiving and reproducing data from the network. Is possible.

Configuration diagram of receiving apparatus according to Embodiment 1 of the present invention Cache list example Data cache processing flow when receiving data Processing flow of the data cache when receiving a notification from the application Configuration diagram of receiving apparatus according to Embodiment 2 of the present invention Example of memory usage list Processing flow of the data cache when receiving a notification from the application

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Receiving device 110 TS receiving unit 120 TS separating unit 130 Video / audio decoding unit 140 Application 150 User input unit 300 Data receiving device 310 Data receiving unit 320 Data cache unit 330 Cache storage unit 340 Application communication unit 350 Data interpretation display unit 400 Cache list 2000 Receiving Device 2010 TS Receiving Unit 2020 TS Separating Unit 2030 Video / Audio Decoding Unit 2040 Application 2050 User Input Unit 2300 Data Receiving Device 2310 Data Receiving Unit 2320 Data Cache Unit 2330 Cache Storage Unit 2340 Application Interpretation Unit 2350 Data Interpretation Display Unit 2400 Cache List 2500 Memory usage list

Claims (43)

A receiving device for receiving and presenting data from a network,
Browser,
An application other than a browser, and the browser
Receiving means for receiving data;
Caching means for caching data received by the receiving means;
A cache storage area for storing data to be cached;
Application status receiving means for receiving notification of the status of other applications;
A cache size determining unit that receives a notification from the application state receiving unit and determines a total size of data that can be cached by the cache unit;
A receiving apparatus comprising: A receiving device for receiving and presenting data from a network,
At least one browser;
At least one non-browser application;
A cache storage area for storing data cached by the browser,
The browser
Receiving means for receiving data;
Caching means for caching data received by the receiving means;
Application status receiving means for receiving notification of the status of other applications;
A cache size determining unit that receives a notification from the application state receiving unit and determines a total size of data that can be cached by the cache unit;
A receiving apparatus comprising: The application status receiving means notifies a data size required by another application,
The receiving device according to claim 1 or 2. The cache determining means determines a total size of data that can be cached from at least the data size received by the application receiving means.
The receiving device according to claim 3. The cache size determining means holds at least application identification information for identifying an application and a data usage list composed of a data size required by the application.
The receiving device according to claim 1 or 2. The application status receiving means receives at least the application identification information and the application status when the application is activated or terminated, and the cache size determining means is configured to receive the application identification information, the application status, and the data usage. Determining the total size of the cacheable data from the quantity list,
The receiving device according to claim 5. The receiving means receives the data usage list, and the cache size determining means rewrites the data size of the data usage list,
The receiving device according to claim 5. When the cached data size is larger than the total size of the cacheable data determined by the cache size determining unit, the cache unit deletes the cached data so that it is less than or equal to the total size of the cacheable data. It is characterized by
The receiving device according to claim 1, 2, 3, or 4. When the cache unit deletes the cached data, it is preferable to delete data with a low reference count,
The receiving device according to claim 8. When the cache means deletes the cached data, the acquisition date and time is deleted preferentially,
The receiving device according to claim 8.   9. The receiving apparatus according to claim 8, wherein when the cache means deletes the cached data, the data transmitted next is preferentially deleted. When the cache unit deletes cached data, it deletes data having a large size preferentially,
The receiving device according to claim 8. When the cache means deletes cached data, the browser data that is not in a valid state is deleted preferentially,
The receiving device according to claim 8. When the cache means deletes the cached data, the browser data with the oldest cache time is deleted preferentially,
The receiving device according to claim 8. The cache means caches a cycle of data that is repeatedly transmitted,
The receiving device according to claim 1, 2 or 8. When the cache means deletes the cached data, the data having a short cycle of repeatedly transmitted data is preferentially deleted,
The receiving device according to claim 15. The cache means caches the time from the request to acquisition of the data acquired by requesting the server,
The receiving device according to claim 1, 2 or 8. When the cache means deletes the cached data, it is characterized by preferentially deleting the data with a short time from the request to the server to the acquisition.
The receiving device according to claim 17. When the cache means deletes the cached data, the half of the cycle of repeatedly transmitted data is compared with the time from the request to the server to obtain, and the cache is deleted with the lowest priority. Characterized by
The receiving device according to claim 15 or 17. Cache size determination procedure for determining the size of data that can be cached from the size of data used by applications other than browsers;
A cache deletion determination procedure that compares the size of cached data with the size of the cacheable data and determines whether deletion of cached data is necessary;
A deletion data determination procedure for determining which cached data is to be deleted when it is determined that deletion of cached data is necessary in the cache deletion determination procedure;
A cache data management method comprising: a data deletion procedure for deleting data determined in the deletion data determination procedure. A cache size determination procedure for determining the size of data that can be cached from the size of data used by an application including the browser, where one or more browsers exist;
A cache deletion determination procedure that compares the size of cached data with the size of the cacheable data and determines whether deletion of cached data is necessary;
A deletion data determination procedure for determining which cached data is to be deleted when it is determined that deletion of cached data is necessary in the cache deletion determination procedure;
A cache data management method comprising: a data deletion procedure for deleting data determined in the deletion data determination procedure. The deletion data determination procedure is characterized in that data with a low reference count is preferentially deleted.
The cache data management method according to claim 20 or 21. The deletion data determination procedure is characterized in that the acquisition date and time are preferentially deleted.
The cache data management method according to claim 20 or 21. The deletion data determination procedure is characterized in that data having a close time to be transmitted next is preferentially deleted.
The cache data management method according to claim 20 or 21. The deletion data determination procedure is characterized in that data having a large size is preferentially deleted.
The cache data management method according to claim 20 or 21. The deletion data determination procedure is characterized in that data of a browser that is not in an effective state is preferentially deleted.
The cache data management method according to claim 21. The deletion data determination procedure is characterized by preferentially deleting data of a browser having an old time when the cache was last used,
The cache data management method according to claim 21. The deletion data determination procedure is characterized in that data having a short cycle of repeatedly transmitted data is preferentially deleted.
The cache data management method according to claim 20 or 21. The deletion data determination procedure is characterized by preferentially deleting data that has a short time from request to the server until acquisition.
The cache data management method according to claim 20 or 21. The deletion data determination procedure is characterized by preferentially deleting data that has a short time from request to the server until acquisition.
The cache data management method according to claim 20 or 21. The deletion data determination procedure is characterized in that half of the cycle of repeatedly transmitted data is compared with the time from when a request is made to the server until it is acquired, and data with a short time is preferentially deleted. ,
The cache data management method according to claim 20 or 21. Cache size determination processing that determines the size of data that can be cached from the size of data used by applications other than browsers;
A cache deletion determination process that compares the size of cached data with the size of the cacheable data and determines whether deletion of cached data is necessary;
A deletion data determination process for determining which cached data to delete when it is determined that the cached data needs to be deleted in the cache deletion determination process;
A cache data management program, or a recording medium on which the program is recorded, comprising: a data deletion process for deleting data determined in the deletion data determination procedure. Cache size determination processing for determining the size of data that can be cached from the size of data used by an application including the browser, where one or more browsers exist;
A cache deletion determination process that compares the size of cached data with the size of the cacheable data and determines whether deletion of cached data is necessary;
A deletion data determination process for determining which cached data to delete when it is determined that the cached data needs to be deleted in the cache deletion determination process;
A cache data management program, or a recording medium on which the program is recorded, comprising: a data deletion process for deleting data determined in the deletion data determination procedure. The deletion data determination process is characterized by preferentially deleting data with a small number of references.
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized in that the acquisition date and time is preferentially deleted.
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized by preferentially deleting data that is close to the next time to be transmitted,
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized in that data having a large size is preferentially deleted.
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized by preferentially deleting browser data that is not in a valid state.
34. A cache data management program according to claim 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized in that the data of the browser having the oldest cache use time is preferentially deleted.
34. A cache data management program according to claim 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized in that data having a short cycle of repeatedly transmitted data is preferentially deleted.
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized in that data to be deleted is preferentially deleted after being requested from the server.
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded. The deletion data determination process is characterized in that data to be deleted is preferentially deleted after being requested from the server.
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded. The deletion data determination procedure is characterized in that half of the cycle of repeatedly transmitted data is compared with the time from when a request is made to the server until it is acquired, and data with a short time is preferentially deleted. ,
34. A cache data management program according to claim 32 or 33 or a recording medium on which the program is recorded.

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