JP2006333293A - Network compression system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a network compression system applicable when analog broadcast is received and digitally recorded. <P>SOLUTION: When the broadcast contents are digitized and compressed, they are compressed so that the data to be recorded are equalized as much as possible by being synthesized between pieces of equipment connected to the system. Then, the size to be recorded is made small by creating difference with reference data in a data base server and holding the difference in a data base server or equipment in a data base server or equipment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to devices such as a hard disk recorder and a personal computer for digitally recording analog broadcast contents, and a database server installed on a communication network for providing a service for improving the compression rate.

  Conventional consumer devices such as hard disk recorders and personal computers for digitally recording analog TV broadcast contents receive the broadcast contents, convert them into a format such as MPEG, and record them directly on a recording device such as a hard disk. In recent years, the capacity of recording devices has increased significantly, but it has not yet fully satisfied user demands. MPEG and other formats used to record broadcast content have greatly reduced the data size by using image difference information between adjacent frames, but the original data volume is very large. Even later data sizes will be quite large.

  By reducing the data size, the time that can be recorded in the recording apparatus is extended, so that an option to extend the recording time by reducing the image quality is usually provided. However, when this option is used, there is a fatal problem that the image quality deteriorates.

  In order to solve the problem that the amount that can be recorded in the recording device is limited, a system / service that makes available a database server installed on a communication network has been proposed. However, although there is an appeal such as being able to respond flexibly when the amount of temporary recording increases and receiving a data backup service, essentially whether the recording device is in home equipment, The only difference is whether it is at the end of the communication network (in the database server), and there is no essential difference in the storage capacity that can be provided at a fixed cost. Companies that provide database server services can reduce costs somewhat by using large-scale recording devices, but they must add line usage fees for communication networks, management costs for recording data, and profits. So it doesn't seem to be very attractive considering it. There seems to be no example of successful implementation of such services on a large scale at least at the present time.

  Patent document 1 solves this problem regarding digital broadcasting. In the case of digital broadcasting, since the digitized data is broadcast from the beginning, it is not encoded by a hard disk recorder or a personal computer, and the broadcast contents are simply digitally recorded. In principle, the recorded data is the same for all devices. In some cases, in order to extend the recording time, after decoding, the image quality may be reduced and re-encoding may be performed. However, if the parameters are the same, the same result can be obtained. Under such conditions, it is considered that there are a lot of identical data on the database server when the recorded contents received from many users are stored in the database server installed on the communication network. At this time, if only one data can be deleted and other data can be deleted, the utilization efficiency of the recording apparatus is remarkably improved. In Patent Document 1, when data of the same program is recorded with a plurality of image quality, the one with the highest resolution is selected, and the data recorded with the low resolution is the same as when recording from the data with high resolution. It is said that the resolution is returned to lower.

  On the other hand, when an analog TV broadcast is received and recorded in the MPEG format, the recorded data is not the same. The reason for this difference is that, in addition to the difference in reception state and the amount of superimposed noise, there is a subtle shift in the recording start time and the I frame timing in the MPEG format.

As is generally known, the MPEG format classifies and compresses each frame of a moving image into an I frame obtained by compressing an image from only one frame of information and a P frame obtained by compressing difference information from the previous frame. . In some cases, a more complicated format using the information of the previous and subsequent frames is also used. In the specification of the MPEG format, it is sufficient that one or more I frames exist somewhere, and all the rest may be P frames. In order to increase the compression rate, it is advantageous to increase the P frame and reduce the I frame as much as possible. In general, I frames are inserted every 0.5 to 1 second in preparation for playback, fast-forwarding, etc.
JP 2003-153152 A

  Although the contents described in Patent Document 1 are excellent methods, there is a problem that they can be applied only to digital broadcasting. Further, since only the data with the highest image quality is recorded, when data with low image quality is recorded, a result that does not necessarily match the recorded content may be returned. The present invention is applicable when analog broadcasting is received and digitally recorded, and nothing other than the same content as data recorded by the device is returned.

  In order to solve the above-described conventional problems, the network compression system of the present invention provides a compression service in which analog broadcasts are received by devices such as a hard disk recorder and a personal computer, and the contents digitally recorded are once connected to a communication network. Sent to the database server. The database server compares the data sent from the device with the reference data and records only the difference in the database server or encrypts the difference and sends it back to the device. For the reference data, use the result of receiving and recording the broadcast contents by the database server operator itself, or using the data created by taking the average value from the data sent for compression. It ’s fine. The latter is more effective for reducing the difference data as much as possible, but it takes a little time for processing, so there are also possible methods depending on the case.

  In order to make the difference data as small as possible, the recording parameters such as the compression rate are unified in each device and the recording timing is matched. When the MPEG format is used as the data recording format, the I frame insertion timing is thus aligned, and the difference for each recorded data can be reduced. To match the timing, use an accurate clock, synchronize the clock using the network, pattern recognition of the broadcast content prior to recording, change in the color and brightness histogram data of the broadcast content It is necessary to synchronize by recognizing the amount. Considering the fact that some deviation is inevitable no matter how accurate the watch is used, and the distance from the broadcasting station and the amount of delay in the wiring from the antenna to the equipment, the contents of the broadcast The method of synchronizing using will be most effective.

  This network compression is once recorded in the device local recording device, sent offline to the database server providing the compression service through the communication network, and the compression result is sent back offline or recorded in the database server. When received, the storage method is not particularly stored locally, and the recording result is sent to the database server in real time, and the compression result is received with a slight delay time, or the database server records it. When receiving the compression result, the uncompressed data is deleted from the device, but if you have both the uncompressed data and the compressed data, you can logically reproduce the reference data. Problem. For this reason, the present invention is essentially irrelevant, but when the compression result is sent back to the device, it will be necessary to encrypt the content so that it cannot be freely manipulated.

  If you want to play back the data after compression, send the compressed data to the database server, or the data recorded on the database server can send back the uncompressed data offline, or streaming technology, etc. A realization mode in which reproduction is performed in real time by using a PC is conceivable.

  Of course, when providing a service that performs compression / playback in real time, even when providing a service that processes offline, some users record only a part of the program, so the recording file of the broadcast content is appropriate. It should be subdivided at intervals, and difference processing should be performed in subdivided units. The subdivision interval can be arbitrarily selected.

  According to the network compression system of the present invention, when the analog broadcast content is digitally recorded, the size of the recorded data can be extremely reduced. Therefore, the number of hours that can be stored in a certain amount of recording device can be dramatically increased.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a conceptual diagram of a network compression system according to Embodiment 1 of the present invention. The data 104 recorded by the device A 101 that records the content of the broadcast received by the antenna 107 is transmitted to the database server 111 that provides a compression service using the communication network 110. The database server 111 records the broadcast content received by the antenna 114 itself as reference data 113. The database server 111 calculates the difference between the data 115 received from the device A 101 and the reference data 113 and records the result 117 in the storage device 112 of the database server 111.

  Note that the “difference” here may be a simple difference that is regarded as a binary data string ignoring the data format, but knows the format of the data, classifies it by component, and sets the difference for each component. By calculating, the difference data of the entire data can be made smaller.

  The system can be implemented online / real-time, offline / non-real-time. A simple system is an offline / non-real-time system, and the data 104 recorded by the device A 101 may be transmitted to the database server 111 while avoiding the time zone in which the network is congested. Subsequent processing is performed by the database server 111. When the recorded data is to be reproduced, the database server 111 creates the original data 115 from the difference information 117 and the reference data 113 recorded in the storage device 112 when the database server 111 is instructed. The data may be returned to the device A101 via this.

  In the case of an online real-time system, the data 104 recorded by the device A 101 is transmitted to the database server 111 via the communication network 110 until it is recorded even during broadcasting. If the difference data 117 is also created in real time, it is not necessary to place large data on the device A. In such a configuration, the original data 115 is created from the difference information 117 and the reference data 113 recorded in the storage device 112 by the database server 111 during playback, and the data is transmitted to the device A 101 via the communication network 110. It returns the same, but instead of returning it as a data file, it can be played back in real time simply by streaming. Of course, if the data is divided into fine times as in the sixth embodiment, real-time processing is possible without using a stream. This will be described later.

  Recording to the database server 111 may be offline / non-real time, and playback may be online / real time.

  Needless to say, although the description is simplified, the number of devices A to C connected to the system is not limited to three, and the number of devices is generally larger, and the number of devices is dynamically increased. It can change. Broadcasting is performed simultaneously on a plurality of channels. When offline processing is performed, parallel processing is also performed on the broadcast contents before and after the same channel. The explanation here is for a case where attention is paid to a specific program (broadcast content) of a specific channel. In actual operation, a plurality of processes will be processed in parallel for each channel and each program.

(Embodiment 2)
FIG. 2 is a conceptual diagram of a network compression system according to Embodiment 2 of the present invention. The difference from Embodiment 1 is that the database server 211 itself does not receive the broadcast, and the total size of the difference data 217 and the like recorded in the database server 211 as much as possible is based on the data sent from each device. The reference value is set to be small.

  In FIG. 2, this system is configured by three devices, device A 201, device B 202, and device C 203, all of which receive broadcasts and send data to the database server 211. In fact, the number of devices is much larger, and it is not known if they will send data for a particular program. If off-line processing is permitted, data may be sent after a considerable amount of time, so it is not realistic to wait for all data to be processed before processing. In that case, the reference value 213 is determined and used so that the total amount of difference data is the smallest in the range by selecting a certain number of data in the order of arrival.

  As for the mounting method of the module 218 for calculating the reference value 213 from a plurality of sent data, how the total amount of differences becomes small depends on the file format of the data and the recording format of the difference data. Usually, it is difficult to aim for the “smallest”, and an algorithm that “makes it as small as possible” will be aimed.

  The following implementation can be considered as a simple algorithm implementation example.

  First, a plurality of sent data is decomposed for each constituent component. Next, for each component, a plurality of pieces of sent data are associated with similar parts. Matching is associating parts that are identical or very similar. For example, an average value of simple numerical values of the matched parts may be used as the reference value for each component. For the part that could not be associated, it is necessary to include the data itself in the difference data as an increasing part, or to include information on the range to be removed as a reduction part from the reference value in the difference data.

  A reference value 213 is constructed from data created for each component.

  If you need more time for offline processing, you can use various values as reference values, actually try to see how much the total size of the difference data will be, and use the smallest value.

(Embodiment 3)
When the first and second embodiments are applied to analog TV broadcasting, the difference between the I frame that uses information of only one frame and the previous frame is generally a moving image recording format. Data is greatly different depending on the position where the I frame enters.

  The simplest way to avoid this problem is to synchronize the timing of the I frame. For example, using a clock adjusted to give accurate time, for example, the first frame started after the hour on every second (just in seconds, when the time less than a second is 0) is defined as an I frame, and otherwise These frames may be defined as P frames. It is generally known how to keep a clock accurate using a communication network. If this mechanism is used, it will be practical enough even if the accuracy of the watch is somewhat inferior.

  However, since the amount of delay varies depending on the distance from the broadcast station and the system configuration from the antenna to the device (for example, cable TV is likely to be a little late), fine adjustment is necessary. Become. A precise time constant set by the user of the device is added to the accurate clock to achieve synchronization.

(Embodiment 4)
The problem with the third embodiment is that it is difficult to determine the fine adjustment amount for synchronization. The fourth embodiment automates the adjustment.

  In the fourth embodiment, the broadcast contents actually received are used for synchronization. A simple implementation is to record an appropriate time on a trial basis, for example 1 second, just before starting the recording, and perform image recognition on it to obtain information such as the position of the person or object in the image. obtain. This is sent together with the time measured by the device clock to the database server via the communication network, and the parameters required for synchronization are requested. The database server matches the image recognition result performed on the reference value, determines how much time should be shifted, and sends information back to the device via the communication network again.

(Embodiment 5)
Although the image recognition is used in the fourth embodiment, the image recognition requires a very long processing time and complicated processing contents. Therefore, it may be difficult to implement in a real-time system. In such a case, it is only necessary to use information that can be obtained more easily, such as a change in the average color of an image for one frame of broadcast content, a change in average brightness, and a volume of audio, and synchronize at the timing when the change occurs. . Although it is inaccurate compared to correctly performing image recognition, it can be implemented more easily.

(Embodiment 6)
It cannot be assumed that all users of this network compression system only record from the beginning to the end of the program when recording the broadcast content. Also, in order to perform real-time processing more simply, if the processing can be started only after reception of the entire program is completed, the usability deteriorates. In order to solve these problems, an appropriate time interval is used as a unit, and data is divided by the unit time.

  For example, if the appropriate time interval is 5 seconds and the first frame and data containing I frames at 1 second intervals are considered as a unit, it can be sent to the database server via the communication network, or the difference can be calculated. This data should be used as a unit. By doing so, the recording start time and end time of the program can be freely set in units of 5 seconds. Further, in the offline processing, there is an advantage that a difference of more than an appropriate time interval (5 seconds in this example) is automatically unrelated.

(Embodiment 7)
In the embodiments so far, the created difference data is stored in the storage device of the database server. The problem with this configuration is that if the number of users who use this network compression system or the amount of data to be recorded is difficult to predict, the storage device of the database server must inevitably be configured with a margin. It will be a costly system.

  In order to avoid this problem, the difference data created by the database server may be sent back to the device using the communication network. Then, the capacity of the storage device required for the database server only needs to have a capacity for storing the reference data and a slight margin for storing the temporary data for work. Even if a very large number of users use this system all at once, the capacity of the reference data does not exceed the total amount of programs broadcast in various places. This is considered to require much less data than the “sum of differential data” when the number of users using this system is very large, and the required capacity can be estimated roughly based on the number of channels and time. Capital investment is possible.

(Embodiment 8)
The problem of the seventh embodiment is that if both the original data and the difference data exist on the device side, there is a possibility that the reference data can be reproduced therefrom. This is different from the contents that the user recorded privately, so there is a problem if it can be reproduced under the current domestic law. Actually, the inverse operation of the difference is not so easy, and such a function is not provided as a device. Furthermore, there should be no problem if the implementation is such that the original data is erased when the difference data arrives from the database server to the device, and the difference data is erased when the original data arrives.

  Although there is almost no problem even if it remains as it is, if you provide a mechanism to record the contents recorded on the device to an external medium such as a DVD or an external hard disk, if you are a malicious user, you can get both the original data and the difference data It becomes possible to put.

  In order to deal with such a problem, the difference data is not sent back from the database server to the device as it is, but is sent back after being encrypted. By doing so, even if both the original data and the encrypted difference data exist on the device, the reference data cannot be reproduced. Various methods are known for the encryption method, and an appropriate one may be selected.

  In the description of the present invention, the case where the analog TV broadcast is digitized and recorded in the MPEG format has been described. However, even if another format is adopted as the recording format, any format using the difference information between frames may be used. There is no essential difference and it goes without saying that the same applies.

  Even when recording in a format that does not use the difference information between frames, in order to provide a real-time service or support partial recording of programs, a method of comparing the recorded contents while separating at regular intervals It is conceivable to take this, and in order to make the separation interval constant, there is no change in having to take synchronization. Therefore, it can be similarly applied.

  The same applies to the recording of audio data for TV broadcasts and when the present invention is applied to radio broadcasts.

  Also, in principle, it is not limited to TV broadcasting and radio broadcasting, but other than that, information of the same content is distributed to many users and can be simply recorded. Needless to say, the present invention can be applied to a digital content that is not the same. For example, there may be a case where the communication record of wireless communication, the contents of lectures and concerts are recorded privately with the permission of the organizer.

  By using the network compression system / apparatus / method according to the present invention, it is possible to dramatically increase the compression rate of data to be recorded in devices that digitally record analog broadcasts such as hard disk recorders and personal computers. Even when the compression result is placed in the database server, the amount of data to be recorded can be considerably reduced, so there is a high possibility that the service can be provided to the user at a low cost. Therefore, it may be used in the fields of home appliances, personal computers, game machines and the like including these functions.

Conceptual diagram of a network compression system in Embodiment 1 of the present invention Conceptual diagram of network compression system according to Embodiment 2 of the present invention

Explanation of symbols

101 Equipment A that receives and records broadcast content
102 Device B that receives and records the contents of the broadcast
103 Equipment C that receives and records the contents of the broadcast
104 Data Recorded by Device A 105 Data Recorded by Device B 106 Data Recorded by Device C 107 Antenna Connected to Device A 108 Antenna Connected to Device B 109 Antenna Connected to Device C 110 Communication Network 111 Database server providing compression service 112 Storage device of database server 113 Reference data 114 Antenna connected to database server 115 Data recorded by device A transferred to database server 116 Data recorded by device A and reference Means for calculating data difference 117 Difference data between data recorded by device A and reference data 201 Device A that receives and records contents of broadcast
202 Equipment B that receives and records the contents of broadcast
203 Equipment C that receives and records the contents of the broadcast
204 Data Recorded by Device A 205 Data Recorded by Device B 206 Data Recorded by Device C 207 Antenna Connected to Device A 208 Antenna Connected to Device B 209 Antenna Connected to Device C 210 Communication Network 211 Database server providing compression service 212 Storage device of database server 213 Reference data 215 Data recorded by device A transferred to database server 216 Means for calculating difference between data recorded by device A and reference data 217 Difference data between data recorded by device A and reference data 218 Module for creating a reference value from data sent from device A, device B, and device C

Claims (8)

A recording system comprising a device that receives and records the content of a broadcast, and a database server that provides a compression service provided on a communication network,
The data recorded by the device is sent to the database server via a communication network,
A network compression system characterized in that data received and recorded by the database server itself is used as reference data, and a difference from the reference data is recorded. The network compression system according to claim 1, wherein data calculated so that a total amount of differences between the plurality of data sent to the database server and the reference data is as small as possible is used as reference data. The network compression system according to claim 1 or 2, wherein when the broadcast content is recorded by the device, the recording timing is synchronized with the other device. The network compression system according to any one of claims 1 to 3, wherein image recording results of broadcast contents are synchronized with the other devices by exchanging with the database server via the communication network. 4. The timing for recording the amount of change in color and brightness of broadcast contents, or the result of voice pattern recognition with the database server via the communication network to synchronize the timing of recording. The network compression system according to any one of the above. The network compression system according to any one of claims 1 to 5, wherein when the received content is recorded by the device, the data is individually recorded at an appropriate time interval. The network compression system according to claim 1, wherein the difference data is sent back from the database server to the device. The network compression system according to any one of claims 1 to 6, wherein the difference data is encrypted from the database server and then sent back to the device.

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