TECHNICAL FIELD 
       [0001]    The present disclosure relates to backward recording, and more particularly related to a method and a system for backward recording in a device having a time-shift function. 
       BACKGROUND ART 
       [0002]    In the current STB program recording application based on DVB (Digital Video Broadcasting) standard, there are two kinds of TV recording modes: one is “instant recording,” and the other is “scheduled recording.” In the “instant recording mode,” a user presses a recording button to launch a record from a specified time which the user is interesting in. When the user thinks that the impressive scene is over, it will be completed by pressing the recording button again to complete the recording. In the “scheduled recording” mode, from the EIT (Event Information Table) transmitted in the DVB PSI/SI (Program Specific Information/Service Information) tables, a user can select the specified events to record the related program in advance. The recording will be launched automatically when the event time is started and will be finished when the event is over. For the two methods mentioned above, the recorded program is stored in the internal/external hard disk. A user can watch the recorded program in anytime. 
         [0003]    However, actually when a user wants to record a live TV program, and the user is only interested in some special scenes, but the user does not know when the interesting points will happen in advance. For example, in a soccer game, fans love to record the scene when a goal happens, but it cannot be known in advance. If users use instant recording, the goal during a match is not known in advance. It is not necessary for users to use scheduled recording to record all of the soccer game. Users are only interested in the goal happens. If a soccer game is totally recorded, when users watch the 90 minutes recording, usually they will use the trick mode method to seek to the goal time to watch the goal scene. The interesting points during a game are usually not over 10 minutes. So it is not necessary to record other 90% contents on the disk. 
       SUMMARY 
       [0004]    To resolve the problems above, a concept of “Backward Recording” is provided by the present invention, which concept may be implemented by a button called “Backward Recording” button that can be added on a remote controller. This allows users to only record a program in the past specified time. For example: for a film, when a user watches a scene that is impressive, and the user thinks that it is valuable to reserve, then can press the “Backward Recording” button to record the scene in past 5 minutes to record the impressive scene. For a football game, after a goal happens, if a user presses the “Backward Recording” button, it will record the game in past  1  minute to include all the goal process. 
         [0005]    According to an aspect of the present invention, it is provided a method for backward recording in a device having a time-shift function, including: launching the time-shift function, when a user select one program, to record the program on a time-shift buffer; receiving an instruction to record a scene backward within the program being viewed by a user: acquiring information on the program from EIT (Event Information Table); determining a type of the program on the basis of the information; setting a duration of the backward recording dependent on the type of the program; and copying a data, which is stored in the time-shift buffer and corresponds to the duration backward from the time of receiving the instruction, in a storage of the device. 
         [0006]    In a first preferred embodiment, the time-shift function is activated in accordance with a default rule or an instruction by the use. 
         [0007]    In a second preferred embodiment, the receiving an instruction is implemented by a backward recording button provided in a user interface of the device. 
         [0008]    In a third preferred embodiment, the information on the program is EIT p/f information or content_nibbel_level_1 received together with the program. 
         [0009]    In a fourth preferred embodiment, the setting is implemented by indicating a proposed duration dependent on the type of the program to the user and being selected by the user. 
         [0010]    In a fifth preferred embodiment, the setting is implemented by selecting default duration dependent or independent on the type of the program. 
         [0011]    In a sixth preferred embodiment, further including the receiving instruction to playback the recorded data stored in the backward recording directory in a storage of the device via a recording playback button provided on the user interface. 
         [0012]    According to an aspect of the present invention, it is provided a computer program product downloadable from a communication network and/or recorded on a medium readable by computer and/or executable by a processor, comprising program code instructions for implementing the foregoing method. 
         [0013]    According to an aspect of the present invention, it is provided non-transitory computer-readable medium comprising a computer program product recorded thereon and capable of being run by a processor, including program code instructions for implementing the foregoing method. 
         [0014]    According to an aspect of the present invention, it is provided a system for backward recording in a device having a time-shift function, comprising a processor to implement: launching the time-shift function, when a user select one program, to record the program on a time-shift buffer; receiving an instruction to record a scene backward within the program being viewed by a user: acquiring information on the program from EIT (Event Information Table); determining a type of the program on the basis of the information; setting a duration of the backward recording dependent on the type of the program; and copying a data, which is stored in the time-shift buffer and corresponds to the duration backward from the time of receiving the instruction, in a storage of the device. 
         [0015]    In a first preferred embodiment, the time-shift function is activated in accordance with a default rule or an instruction by the use. 
         [0016]    In a second preferred embodiment, the receiving an instruction is implemented by a backward recording button provided in a user interface of the device. 
         [0017]    In a third preferred embodiment, the information on the program is EIT p/f information or content_nibbel_level_1 received together with the program. 
         [0018]    In a fourth preferred embodiment, the setting is implemented by indicating a proposed duration dependent on the type of the program to the user and being selected by the user. 
         [0019]    In a fifth preferred embodiment, the setting is implemented by selecting default duration dependent or independent on the type of the program. 
         [0020]    In a sixth preferred embodiment, further including the receiving instruction to playback the recorded data stored in the backward recording directory in a storage of the device via a recording playback button provided on the user interface. 
         [0021]    It is to be understood that more aspects and advantages of the invention will be found in the following detailed description of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, will be used to illustrate an embodiment of the invention, as explained by the description. The invention is not limited to the embodiment. 
           [0023]    In the drawings: 
           [0024]      FIG. 1  illustrates an exemplary block diagram of a system  100  according to an embodiment of the present invention; 
           [0025]      FIG. 2  illustrates a flow chart illustrating how backward recording function is implemented according to an embodiment of the present invention; and 
           [0026]      FIG. 3  illustrates system chart showing how a user implements backward recording function according to an embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0027]    In the following description, various aspects of an embodiment of the present invention will be described. For the purpose of explanation, specific configurations and details are set forth in order to provide a thorough understanding. However, it will also be apparent to one skilled in the art that the present invention may be implemented without the specific details present herein. 
         [0028]    An embodiment of the present invention includes “Backward Recording” function, which lets a user record only interesting scenes in the past time. By adding the function, it will be not necessary to record all of TV programs and the disk space of the STB storage device can be saved. 
         [0029]      FIG. 1  illustrates an exemplary block diagram of a system  100  according to an embodiment of the present invention. The system  100  can be a TV set, computer system, tablet, and so on. The system  100  comprises a CPU (Central Processing Unit)  111 , a storage  113 , a display  115 , and a user input module  117 . A memory  119  such as RAM (Random Access Memory) may be connected to the CPU  111  as shown in  FIG. 1 . A device  110  including the CPU  111 , the storage  113 , and the memory  119  can be a STB (Set Top Box) or a recorder that is preferably based on DVB standard. 
         [0030]    The display  115  is configured to visually present text, image, video and any other contents to a user of the system  110 . The storage  113  is configured to store software programs and data for the CPU  111  to drive and operate the process to record contents in accordance with the embodiment of the present invention. The user input module  117  may include keys or buttons to input characters or commands and also comprises a function for recognizing the characters or commands input with the keys or buttons. The user input module  117  can be omitted in the system depending on use application of the system. 
         [0031]      FIG. 2  illustrates a flow chart illustrating how backward recording function is implemented according to an embodiment of the present invention. As a precondition, time-shift function must be enabled in the device  110  to support the automatic recording function. The time-shift function is to buffer at least one program in predetermined period, such as several hours or several weeks in the past. In addition to this, one “record backward” button is added for user&#39;s selections on the user input module  117 . The button can be added via the user input module  117  to provide the key available. 
         [0032]    At step  201 , when the device  110  is boot up and zapping to a specified channel to watch an event by a user, the time-shift buffer is automatically launched. The default buffer size is 2 hours which means it can automatically buffer 2 hours program. The size of default buffer size can be changed as needed. The device  110  can access EIT information by EIT manager to acquire information on the event. The EIT manager is installed in the device  110 . In this embodiment, the time-shift function is launched when a user select one event, and however, the time-shift function may be applied to all of events during activation of the device  110  automatically. The system may recognize that a user select one service after predetermined time has past. 
         [0033]    At step  203 , the device  110  receives an instruction to start backward recording function for an event which a user is watching when the user finds past scene is meaningful for recording and presses the “record backward” button. 
         [0034]    At step  205 , the device  110  gets EIT information for the event, and determines the event type. As described below, Content Descriptors of EIT p/f information content_nibbel_level_1 can be used to determine the event type. 
         [0035]    At step  207 , the device  110  sets recording duration in accordance with default times for each event type or selected time by the user manually through the user input module  117 . 
         [0036]    At step  209 , the device  110  copies data of the past duration from the time of receiving the instruction stored in the time-shift buffer to the “Backward Recording” directory in the storage  113  of the device  110 . The storage could be internal/external hard disk. 
         [0037]    After the recording completion, the user can playback the recorded event like instant/scheduled recording from the stored directory. There are two methods how to store data in the record library as follows:
       1. Program type: For example, there are movie, song, and sports sub-directory under the record library directory; and   2. Record time (and/or date): For example, there are 2014-01-01, and 2014-01-02 sub-directory under the record library directory.
 
As described above, The backward recording function can be organized with the program type as it can be got from EIT event information. It also can be organized with the time sequence. If the device  110  is turned off, go to step  211  to terminate the backward recording function. Otherwise, backward recording function continues and is ready to next recording.
       
 
         [0040]    In one embodiment, the default backward recording time is set in accordance with an event type which a user is watching. If the even type is Sports, the default backward recording time is 1 minute. The EIT p/f information is utilized to judge the event type. If the program is a sport game, the backward recording function is typically for a scene a goal happens. If the event type is Movie/Drama, the default backward recording time is 10 minutes. The most impressive of a film scene is about 10 minutes. If the event type is Music/Ballet/Dance, the default backward recording time is 4 minutes. Typically one song duration is about 4 minutes. By default, a message to let user choose how much time the user wants to record for the past scene may be presented. 
         [0041]    The referred EIT p/f information is for content descriptor used in the EIT present/following information. Table1-1 describes the content descriptor definition defined in DVB-SI standard (ETSI 300 468). If there is no content descriptor, then the default backward recording time is 5 minutes. 
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 1-1 
               
             
             
               
                   
               
               
                 Content Descriptor 
               
             
          
           
               
                   
                 Syntax 
                 Number of bits 
                 Identifier 
               
               
                   
                   
               
               
                   
                 Content Descriptor ( ) { 
                   
                   
               
               
                   
                 descriptor _tag 
                 8 
                 Uimbsf 
               
               
                   
                 descriptor_length 
                 8 
                 Uimbsf 
               
               
                   
                 For (I =0; i&lt;N; i++) { 
                   
                   
               
               
                   
                  content_nibbel_level_1 
                 4 
                 Uimbsf 
               
               
                   
                  content_nibbel_level_2 
                 4 
                 Uimbsf 
               
               
                   
                  User_byte 
                 8 
                 Uimbsf 
               
               
                   
                 } 
               
               
                   
                   
               
             
          
         
       
     
         [0042]    The content_nibbel_level_1 is also defined in ETSI 300468. It is defined with different event type. For different events, they can be mapped to backward recording default durations. For example, a movie event&#39;s interesting point may last 10 minutes for backward recording. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 1-2 
               
             
             
               
                   
               
               
                 Content Nibbel_level_1 definition and map to the default backward 
               
               
                 recording duration 
               
             
          
           
               
                 Content_ 
                   
                 Default backward 
               
               
                 nibbel_level_1 
                   
                 recording duration 
               
               
                 code 
                 Description 
                 (minutes) 
               
               
                   
               
             
          
           
               
                 0x1 
                 Movie/Drama: 
                 10 
               
               
                 0x2 
                 News/Current affairs: 
                 1 
               
               
                 0x3 
                 Show/Game show: 
                 2 
               
               
                 0x4 
                 Sports: 
                 1 
               
               
                 0x5 
                 Children&#39;s/Youth programmes: 
                 3 
               
               
                 0x6 
                 Music/Ballet/Dance: 
                 4 
               
               
                 0x7 
                 Arts/Culture (without music): 
                 5 
               
               
                 0x8 
                 Social/Political issues/Economics: 
                 5 
               
               
                 0x9 
                 Education/Science/Factual topics: 
                 5 
               
               
                 0x0A 
                 Leisure hobbies: 
                 5 
               
               
                 0x0B 
                 Special characteristics: 
                 5 
               
               
                 Others 
                 Others 
                 5 
               
               
                   
               
             
          
         
       
     
         [0043]      FIG. 3  illustrates system chart showing how a user implements backward recording function according to an embodiment of the present invention in more details. In this embodiment, the device  110  is a STB. A user watching TV presses CH+/CH− button ( 301 ) and changes a channel to one service ( 303 ). The time-shift function is enabled in the STB; and the time-shift buffer automatically filling ( 305 ). The EIT table information is available by STB EIT Manager ( 307 ). 
         [0044]    The user presses the backward recording button when the user finds past scene is meaningful for recording ( 309 ). The STB acquires the current service content_nibbel_level_1 from the EIT content descriptor nibbel level information ( 311 ,  313 ). The STB can also utilize EIT p/f information instead. 
         [0045]    The STB UI can indicate proposed recording duration in accordance with the content descriptor to let user select it ( 317 ). Alternatively, the recording duration can be set as a default relating to/non-relating to the content descriptor. Alternatively, both approach can be applied simultaneously to let the user select accordingly. 
         [0046]    The STB copies the service crip with the recording duration from the time-shift buffer to the “Backward Recording” directory in the storage of the STB via the recording manager. The recoding starts from the time when the user presses the backward recording button and records backward the service crip within the recording duration ( 319 ). When the recording is finished, the STB UI may indicates it to the user ( 321 ). The user can playback the recorded service crip like instant/scheduled recording for the stored directory. For playback, the user presses a recording playback button ( 323 ). The STB retrieves the data stored in the “Backward Recording” directory in the storage via STB recording manager ( 325 ) to playback ( 327 ). 
         [0047]    A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. For example, elements of different implementations may be combined, supplemented, modified, or removed to produce other implementations. Additionally, one of ordinary skill will understand that other structures and processes may be substituted for those disclosed and the resulting implementations will perform at least substantially the same function(s), in at least substantially the same way(s), to achieve at least substantially the same result(s) as the implementations disclosed. Accordingly, these and other implementations are contemplated by this application and are within the scope of the invention as defined by the appended claims.
It is provided a method for backward recording in a device having a time-shift function, including: launching the time-shift function, when a user select one program, to record the program on a time-shift buffer; receiving an instruction to record a scene backward within the program being viewed by a user: acquiring information on the program from EIT(Event Information Table); determining a type of the program on the basis of the information; setting a duration of the backward recording dependent on the type of the program; and copying a data, which is stored in the time-shift buffer and corresponds to the duration backward from the time of receiving the instruction, in a storage of the device.