Abstract:
The present invention has been made to adequately perform edit recording in a recording/reproducing apparatus which refers to, reconstructs, and writes back the content of a base recorded in a recording medium at the time of the edit recording. The present invention provides an edit recording method for use in a recording/reproducing apparatus which refers to, reconstructs, and writes back the content of a base recorded in a recording medium at the time of the edit recording, including the steps of acquiring, in error-correcting-processing-unit, position information indicating the last record position at the end time of recording, calculating an edit recording-standby point a predetermined distance before the acquired last record position set as the edit recording starting point, setting operation mode to a recording-standby state at the calculated edit recording-standby point, and repeating “recording”, “recording-standby”, and “recording” based on the position information in error-correcting-processing-unit at the end time of recording.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present invention contains subject matter related to Japanese Patent Application JP 2004-250823 filed in Japanese Patent Office on Aug. 30, 2004, the entire contents of which being incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a edit recording method for use in a recording/reproducing apparatus such as a video tape recorder and a recording/reproducing apparatus.  
         [0004]     2. Description of the Related Art  
         [0005]     A format for compressing video data according to, for example, a DV (Digital Video) system and recording the video data on a magnetic tape has been specified as a DV format of a consumer digital video tape recorder.  
         [0006]     In the above format, in order to effectively perform a edit recording in which a recorded video image and a newly-input video image are connected to each other for recording, the data (system data) needed for the edit recording are set, for each predetermined number of pictures, at the front stage of the pictures in bulk, and thereby the edit recording can be started from any frame. The edit recording is started from the top of frames. When a recording current is supplied in sync with a frame pulse, the edit recording can be started (refer to, for example, Jpn. Pat. Appln. Publication No. Hei.7-75413).  
         [0007]     A format for compressing video data according to, for example, an HDV system and recording the video data on a magnetic tape has been specified as an HDV format of a digital video tape recorder. With this format, variable length data having a variable frame size such as an MPEG-PES (Packtized Elementary Stream) is recorded on a magnetic tape (refer to, for example, Jpn. Pat. Appln. Laid-Open-Publication No. 2004-164731).  
       SUMMARY OF THE INVENTION  
       [0008]     When the edit recording is performed for variable length data having a variable frame size such as an MPEG-PES (Packtized Elementary Stream), the location at which the edit recording can be performed is limited to, for example, where I-picture or P-picture exists. Therefore, it is necessary to search a start point of edit recording before the edit recording. Further, when the obtained start point is adopted without modification, the edit recording may be started from an unintended location, in some cases. Further, even when a recording current is supplied in sync with a frame pulse, the edit recording may fail in some cases. In this case, it is necessary to supply the recording current from the start point of the edit recording exactly.  
         [0009]     In view of the above situation, it is desirable to provide a edit recording method that allows a edit recording to be performed adequately and a recording/reproducing apparatus.  
         [0010]     The advantages and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings.  
         [0011]     According to the present invention, there is provided an edit recording method for use in a recording/reproducing apparatus which refers to, reconstructs, and writes back the content of a base recorded in a recording medium at the time of the edit recording, including the steps of: acquiring, in error-correcting-processing-unit, position information indicating the last record position at the end time of recording; calculating an edit recording-standby point a predetermined distance before the acquired last record position set as the edit recording starting point; setting operation mode to a recording-standby state at the calculated edit recording-standby point; and repeating “recording”, “recording-standby”, and “recording” based on the position information in error-correcting-processing-unit at the end time of recording.  
         [0012]     According to the present invention, there is provided a recording/reproducing apparatus which refers to, reconstructs, and writes back the content of a base recorded in a recording medium at the time of the edit recording, including: control means for acquiring, in error-correcting-processing-unit, position information indicating the last record position at the end time of recording, calculating a edit recording-standby point a predetermined distance before the acquired last record position set as the edit recording starting point, and setting operation mode to a recording-standby state at the calculated edit recording-standby point, wherein “recording”, “recording-standby”, and “recording” are repeated based on the position information in error-correcting-processing-unit at the end time of recording.  
         [0013]     According to the present invention, it is possible to adequately perform the edit recording. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a block diagram showing a configuration of a recording/reproducing apparatus according to the present invention;  
         [0015]      FIG. 2  is a view schematically showing a data recording state on a DRAM and a magnetic tape in the recording/reproducing apparatus,  
         [0016]      FIG. 3  is a table showing the content of ECCTB;  
         [0017]      FIG. 4  is a view schematically explaining searching of a edit recording starting point in the recording/reproducing apparatus and a method of inevitably finding the same edit staring point when the edit point is searched from the same tape position;  
         [0018]      FIG. 5  is a flowchart showing the procedure performed when the edit recording that repeats “recording”, “recording-standby”, and “recording” is executed;  
         [0019]      FIG. 6  is a view schematically explaining a control performed at the recording end time;  
         [0020]      FIG. 7  is a view schematically explaining a case where the edit recording is started from a currently reproduced image;  
         [0021]      FIG. 8  is a flowchart showing the procedure for controlling recording start timing; and  
         [0022]      FIG. 9  is a view schematically showing control for recording start timing in the edit recording. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following embodiment and can be arbitrarily modified without departing from the spirit and scope of the invention.  
         [0024]     The present invention is applied, for example, to a recording/reproducing apparatus  100  as shown in  FIG. 1 .  
         [0025]     The recording/reproducing apparatus  100  records input video data and audio data on a magnetic tape  40  through a rotation head  30  while allowing a recording processing section  10 , which operates under the control of a controller  20 , to form a predetermined data unit (hereinafter, referred to as “pack”) on a DRAM  14 . Further, the recording/reproducing apparatus  100  allows the rotation head  30  to read out video data and audio data recorded, as a pack, on the magnetic tape  40 , store the read out data in the DRAM  14 , and allows a reproduction processing section  50  to reproduce the video data and audio data. In order to realize the above functions, the recording/reproducing apparatus  100  has the controller  20  which controls the operations of the recording processing section  10  and reproduction processing section  50  and a system controller  80  which controls the controller  20  to record data stored in the DRAM  14  onto the magnetic tape  40  or to readout data from the magnetic tape  40  so as to store the readout data on the DRAM  14 .  
         [0026]      FIG. 2  shows a data recording state on the DRAM  14  and magnetic tape  40  in the recording/reproducing apparatus  100 .  FIG. 2  shows a recording state of video data having a GOP structure of N=15 (I-picture is placed every 15 pictures) and M=3 (P-picture is placed every 3 pictures) on the DRAM  14  and magnetic tape  40 . That is, one pack is constituted by M (three, in this case) picture data, AUX data (AUX-V: U in  FIG. 2 ) related to the picture, audio data (A in  FIG. 2 ) related to the picture, and AUX data (AUX-A: X in  FIG. 2 ) related to the audio data.  
         [0027]     In the recording/reproducing apparatus  100 , the data stored in the DRAM  14  is subjected to ECC (Error Correcting Code) processing with data corresponding to 16 tracks as a unit, and thereby ECCTB (Error Correction Code Table Block) (H in  FIG. 2 : packet placed in a sync block to be assigned to the recording of the top of ECC block) storing predetermined information is placed on the first track of every 16 tracks. A unit including 16 tracks, which is a unit of ECC processing, is referred to as ECC bank.  
         [0028]     When the top of the pack that can be set as a edit recording starting point is included in the ECC bank, the data indicating that is set in the corresponding ECCTB. Similarly, when the top of the pack that can be set as a edit recording starting point is not included in ECC bank, the data indicating that is set in the corresponding ECCTB. That is, the ECCTB can store a point from which the edit recording can be started.  
         [0029]      FIG. 3  shows the content of the ECCTB.  
         [0030]     The recording processing section  10  of the recording/reproducing apparatus  100  includes a compression section  11  for video data, a compression section  12  for audio data, a system data generation section  13 , a DRAM  14 , an ECC processing section  15  and an input/output section  16 .  
         [0031]     The compression section  11  compresses an input HD video signal according to MPEG system and outputs the obtained video data to the DRAM  14 . The compression section  12  compresses an audio signal corresponding to the HD video signal according to a system conforming to, for example, MPEG 1 Layer 2 and outputs the obtained audio data to the DRAM  14 .  
         [0032]     The system data generation section  13  generates system data constituted by AUX data or sub-code data and outputs the system data to the DRAM  14 .  
         [0033]     The video data compressed by the compression section  11 , audio data compressed by the compression section  12 , and system data generated by the system data generation section  13  are stored in the DRAM  14  in such a manner to form packs.  
         [0034]     The DRAM  14  can store data corresponding to six ECC banks. When the input data exceeds that amount, the excess data is sequentially overwritten on the previously stored data.  
         [0035]     The ECC processing section  15  applies ECC processing to video data, audio data, and system data constituting the pack with an ECC bank being as a unit. The ECC processing section  15  applies error correcting processing to the data that is stored in the DRAM  14  after being read out from the magnetic tape  40  by the input/output section  16 .  
         [0036]     The input/output section  16  modulates the data (the data that has been subjected to ECC processing) stored in the DRAM  14  to a system suitable to be recorded on the magnetic tape  40  and records the modulated data on the magnetic tape  40  through the rotation head  30 . Further, the input/output section  16  allows the DRAM  14  to store the data that has been read out from the magnetic tape  40  through the rotation head  30 .  
         [0037]     The controller  20  controls the above sections in the recording processing section  10 .  
         [0038]     The system controller  80  controls the controller  20  to record data stored in the DRAM  14  onto the magnetic tape  40  or to read out data from the magnetic tape  40  so as to store the readout data on the DRAM  14 .  
         [0039]     Next, referring to  FIG. 4 , searching of a edit recording starting point and a method of inevitably finding the same edit staring point when the edit point is searched from the same tape position will be described.  
         [0040]     Firstly, the system controller  80  starts tape drive and waits for tracking achievement (a 1  in  FIG. 4 ). In this state, the system controller  80  instructs the controller  20  of the recording/reproducing apparatus  100  to search the starting point of edit recording, thereby starting the searching (c 1  in  FIG. 4 ). Then, in the recording/reproducing apparatus  100 , reproduction data is read out from the magnetic tape  40  by the rotation head  30  and stored in the DRAM  14  through the input/output section  16 . After that, the controller  20  allows the ECC processing section  15  to perform error correcting processing and starts the search of the starting point of edit.  
         [0041]     In the recording/reproducing apparatus  100 , when finding the starting point of edit, the controller  20  notifies the system controller  80  of the ECC bank number corresponding to the starting point (d 1  in  FIG. 4 ). When determining that the ECC bank number notified by the controller  20  is a desired starting point, the system controller  80  acquires the ECC bank number and ATN (Absolute Track Number) which is included in ECCTB and indicates the distance between the top of the above ECC bank and tape top and promptly stops tape drive (e 1  in  FIG. 4 ).  
         [0042]     When the ECC bank number corresponding to the edit starting point is notified from the controller  20  of the recording/reproducing apparatus  100  to the system controller  80 , the recording processing section  10  is performing error correcting processing for the bank. Therefore, actual tape position of the ECC bank corresponding to the starting point of edit exists at the position before the current position (in other words, actual tape position exists on the tape top side relative to the current position) (f 1  in  FIG. 4 ).  
         [0043]     When receiving the notification related to the edit starting point, the system controller  80  rewinds the magnetic tape  40  to the previous position relative to the starting point (g 1  in  FIG. 4 ) and stabilizes a tape path so that the rotation head  30  can correctly read the magnetic tape  40  (h 1  in  FIG. 4 ). After that, the system controller  80  allows the magnetic tape  40  to run at a lower speed of ⅓ fold speed (i 1  in  FIG. 4 ) and searches the position a fixed distance (sufficient distance for recording operation to start: j 1  in  FIG. 4 ) before the starting position of edit recording. When finding the position a fixed distance before the starting-position, the system controller  80  enters a recording-standby state (k 1  in  FIG. 4 ).  
         [0044]     With the method described above, searching of the starting point of edit is completed. At this time, the waiting time indicated by b in  FIG. 3  has been set. Thus, when the starting point of edit is searched from the same tape position, it is possible to inevitably find the same staring point of edit. The waiting time indicated by b 1  shown in  FIG. 4  is determined depending on the distance of k 1  in  FIG. 4 .  
         [0045]     Next, a method of acquiring the start point of the edit will be described in such a manner to correspond to a user&#39;s request.  
         [0046]     The edit recording that a user requests includes patterns of: 
    1. Repeating “recording”, “recording-standby”, and “recording”.     2. Starting edit recording from complete stop state.     3. Starting edit recording from currently reproduced image. 
 
 Hereinafter, respective patterns will be described. 
   
 
         [0050]     Firstly, the pattern of 1. will be described with reference to a flowchart of  FIG. 5 .  
         [0051]     At the end time of recording, the system controller  80  acquires the number of ECC bank that includes video data most recently recorded from the controller  20  of the recording/reproducing apparatus  100  and ATN included in ECCTB header of that bank (Step S 1 ).  
         [0052]     Then, the system controller  80  sets the bank as a starting point of edit, rewinds the magnetic tape  40  by a fixed distance from the edit starting point (step S 2 ), allows recording operation to enter a recording-standby state (step S 3 ), and performs the same processing as g 1  to j 1  shown in  FIG. 4 , thereby preparing for the next recording start time.  
         [0053]     A control performed at the end time of the recording is shown in  FIG. 6 .  
         [0054]     Upon receiving an instruction to end recording operation during the recording operation (a 2  in  FIG. 6 ), the system controller  80  turns off a recording current at the time point when null-writing has been performed by one bank BKnull in the train of the most recently recorded bank (BKend) (starting point of edit recording) that includes V-END indicating recording end and stops a capstan after a fixed distance has been traveled (c 2  in  FIG. 6 ). Then, the system controller  80  rewinds (e 2  in  FIG. 6 ) the magnetic tape  40  by a predetermined distance (distance from capstan stop point to recording-standby point (d 2  in  FIG. 6 )+distance required to stabilize tape path+distance for fine adjustment) and stabilizes a tape path so that the rotation head  30  can correctly read the magnetic tape  40  (f 2  in  FIG. 6 ). After that, the system controller  80  allows the magnetic tape  40  to run at a lower speed of ⅓ fold speed (g 2  in  FIG. 6 ) and searches the position a fixed distance (h 2  in  FIG. 6 ) before the starting position of edit recording. When finding the position a fixed distance before the starting position, the system controller  80  enters a recording-standby state (i 2  in  FIG. 6 ).  
         [0055]     In the case of the pattern of 2., by using the above mentioned searching of a edit recording starting point and the method of inevitably finding the same edit starting point when the edit starting point is searched from the same tape position, it is possible to find a edit starting point closest to the current tape stop position.  
         [0056]     The pattern of 3. will next be described with reference to a flowchart of  FIG. 5 .  
         [0057]     When the operation enters a pause state during reproduction, the tape stop position (b 3  in  FIG. 7 ) differs from the tape position (a 3  in  FIG. 7 ) at which an image that a user is actually viewing has been recorded. The tape position of the top of the image on the tape position (a 3  in  FIG. 7 ) at which an image that a user, is actually viewing has been recorded can be calculated by using ETN (Extended Track Number: value indicating the position relative to the top of the different tape from the case of ATN). The ETN can be calculated from DTS (Decoding Time Stamp) that can be acquired from another microcomputer that controls not shown Encode/Decode as follows. 
 
 DTS= ( ETN− 10)×(clock number/10) 
        clock number: 3003 in the case of NTSC and 3600 in the case of PAL        
 
         [0059]     Thus, after calculating the tape position (a 3  in  FIG. 7 ) at which an image that a user is actually viewing has been recorded, the system controller  80  rewinds (c 3  in  FIG. 7 ) the magnetic tape  40  to the tape top side relative to the position a 3  shown in  FIG. 7  from the reproduction pause position and performs detection of the start point of edit (d 3  in  FIG. 7 ). At the time when the controller  20  of the recording/reproducing apparatus  100  notifies the system controller  80  that the starting point of edit has been detected, the system controller  80  compares the values of ETN indicating bank top included in the ECCTB header of the ECC bank corresponding to the detected edit starting point with the tape position (a 3  in  FIG. 7 ) at which an image that a user is actually viewing has been recorded. At this time, when the system controller  80  does not adopt the detected starting point until the magnitude of the above ETN value exceeds the value of the tape position (a 3  in  FIG. 7 ) at which an image that a user is actually viewing has been recorded, it is possible to perform the edit recording in such a manner that the image that a user is viewing remains. In this case, the edit starting point is a position e 3  shown in  FIG. 7 .  
         [0060]     When the edit starting point is found, the system controller  80  rewinds the magnetic tape  40  to the previous position relative to the starting point (f 3  in  FIG. 7 ) and stabilizes a tape path so that the rotation head  30  can correctly read the magnetic tape  40  (g 3  in  FIG. 7 ). After that, the system controller  80  allows the magnetic tape  40  to run at a lower speed of ⅓ fold speed (h 3  in  FIG. 7 ) and searches the position a fixed distance (sufficient distance for recording operation to start: i 3  in  FIG. 7 ) before the starting position of edit recording. When finding the position a fixed distance before the starting position, the system controller  80  enters a recording-standby state (j 3  in  FIG. 7 ).  
         [0061]     An operation for recording start timing control will next be described with reference to a flowchart of  FIG. 8  and  FIG. 9 .  
         [0062]     Firstly, the system controller  80  starts tape drive and waits for tracking achievement (step S 11 ).  
         [0063]     The system controller  80  then reads out data that has already been on the magnetic tape  40  to acquire ATN (ETN) indicating the position of the magnetic tape  40 , thereby grasping the position of the magnetic tape  40  (step S 12 ).  
         [0064]     The system controller  80  then determines whether a position several tracks before the recording starting point has been reached or not. When determining that a position several tracks before the recording starting point has been reached (step S 13 ), the system controller  80  stops the acquisition of the data that has already been recorded on the magnetic tape  40  and the system controller  80  itself counts the tape position until the recording starting point has been reached (step S 14 ).  
         [0065]     The system controller  80  then determines whether the recording starting point has been reached or not. When determining that the recording starting point has been reached (step S 15 ), the system controller  80  instructs the controller  20  of the recording/reproducing apparatus  100  to start recording of the data stored on the DRAM  14  onto the magnetic tape  40  through the input/output section  16  and rotation head  30  (step S 16 ).  
         [0066]     When receiving an instruction of starting the recording operation in a state of being in recording standby state at the position of the most recently recorded bank (BKend), that is, at the position a fixed distance (a 4  in  FIG. 9 ) before the start point of edit recording, the system controller  80  activates the capstan to start the tape drive (b 4  in  FIG. 9 ), waits for tracking achievement (c 4  in  FIG. 9 ), stops the acquisition of the data recorded on the magnetic tape  40  at the time point when a position several tracks before the recording starting point has been reached, and counts, by itself, the tape position until the recording starting point has been reached (d 4  in  FIG. 9 ). When the recording starting point has been reached, the system controller  80  instructs the controller  20  of the recording/reproducing apparatus  100  to start recording of the data stored on the DRAM  14  of the recording processing section  10  onto the magnetic tape  40  through the input/output section  16  and rotation head  30  (e 4  in  FIG. 9 ).  
         [0067]     That is, the starting point of the edit recording can be obtained at the time when the recording starting bank corresponding to the edit recording starting point, that is, the position (TRP/ETN) of the first track of the most recently recorded bank (BKend) and the position of the track that the system controller  80  itself counts until the recording starting point has been reached correspond to each other. The difference existing until the above correspondence is phase difference (f 4  in  FIG. 9 ).  
         [0068]     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alternations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.