Method and Apparatus for Recording and Playing Back Monitored Video Data

Abstract

A method and an apparatus are provided for recording and playing back monitored video data for recording monitored video data generated continuously for a long time on a magnetic tape. Video signals from a video camera are converted to digital signals in an A/D converter, compressed and encoded in a compression encoder and decoder circuit, then transferred to a time axis compression circuit which includes a first memory, the second memory, an SCSI controller, and a hard disk unit. The digital signal is thereafter compressed on the time axis and recorded on the magnetic tape loaded in a D-VHS standard VTR via an I/F circuit.

1 . A method of recording/playing back video data on/from a recording medium comprising: 
 performing an in-frame compression coding on video data by m frames, with m being an integer equal to or greater than 2, and an inter-frame compression coding on the video data for the frames other than said m frames;    temporarily storing the video data in a first memory as digital compressed data;    separating the in-frame compression coded data from the inter-frame compression coded data that have been recorded in said first memory;    reading the in-frame compression coded data having n serial frames, with n being an integer equal to or greater than 2, and the other inter-frame compression coded data alternately at an output data rate higher than an input data rate to said first memory; and    intermittently recording the read data on said recording medium.    
   
   
       2 . A method of recording/playing back video data on/from a recording medium available to be detachably inserted into a main body of an apparatus comprising: 
 performing an in-frame compression coding on a video data by m frames, with m being an integer equal to or greater than 2, and an inter-frame compression coding on the video data for the frames other than said m frames;    temporarily storing the video data in a first memory as digital compressed data;    separating the in-frame compression coded data from the inter-frame compression coded data that have been recorded in said first memory;    alternately reading the in-frame compression coded data having n serial frames, with n being an integer equal to or greater than 2, and the other inter-frame compression coded data;    recording the read data in a hard disk;    playing back said data recorded in said hard disk and temporarily recording the played back data in a second memory; and    reading as a unit a predetermined amount of the data recorded in said second memory and recording the read data on the recording medium available to be detachably inserted into the main body of the apparatus,    wherein, when the data recorded on said recording medium available to be detachably inserted into the main body are played back, a normal playback mode with said in-frame compression coded data and said inter-frame compression coded data which have been separated, and a special playback mode only with said in-frame compression coded data are selectively performed.    
   
   
       3 . A method of recording/playing back video data on and/or from a recording medium available to be detachably inserted into a main body of an apparatus comprising: 
 thinning out the video data to be input on a time axis;    performing an in-frame compression coding on said video data that have been thinned out and temporarily recording it in a first memory;    reading said data from said first memory and recording the read data in a hard disk;    playing back said data in said hard disk and temporarily recording the played back data in a second memory; and    reading as a unit a predetermined amount of the data in said second memory and recording the read data on the recording medium available to be detachably inserted into the main body of the apparatus,    wherein a special playback mode is performed with said in-frame compression coded data when the data recorded on said recording medium available to be detachably inserted into the main body of the apparatus are played back.    
   
   
       4 . A recording and playback apparatus for recording/playing back video data on/from a recording medium, comprising: 
 first memory means for performing an in-frame compression coding on the video data by m frames, with m being an integer equal to or greater than 2, and an inter-frame compression coding on the video data for frames other than said m frames, and temporarily recording the video data as digital compressed data; and    recording and playback means for separating the in-frame compression coded data from the inter-frame compression coded data in the first memory means, reading the in-frame compression coded data having n serial frames, with n being an integer equal to or greater than 2, and the other inter-frame compression coded data alternately at a first transfer rate that is higher than an input data rate to said first memory means, and recording the read data on said recording medium.    
   
   
       5 . A recording and playback apparatus for recording/playing back video data on/from a recording medium available to be detachably inserted into a main body of the apparatus, comprising: 
 first memory means for performing an in-frame compression coding on the video data by m frames, with m being an integer equal to or greater than 2, and an inter-frame compression coding on the video data for frames other than said m frames, and temporarily recording the video data as digital compressed data;    means for recording/playback, respectively, on/from a hard disk that separates the in-frame compression coded data from the inter-frame compression coded data in the first memory means, alternately reads the in-frame compression coded data having n serial frames, with n being an integer equal to or greater than 2, and the other inter-frame compression coded data, and records the read data in the hard disk;    second memory means for playing back the data from the means for recording/playback, respectively, on/from a hard disk and temporarily recording the played back data; and    means for recording/playback, respectively, on/from a medium that reads as a unit a predetermined amount of the data from the second memory means and records the read data on the recording medium available to be detachably inserted into the main body of the apparatus,    wherein the data recorded on said recording medium available to be detachably inserted into the main body are played back, a normal playback mode with said in-frame compression coded data and said inter-frame compression coded data which have been separated, and a special playback mode only with said in-frame compression coded data are selectively formed.    
   
   
       6 . A recording and playback apparatus for recording/playing back video data on/from a recording medium available to be detachably inserted into a main body of the apparatus, comprising: 
 thinning out means for thinning out the video data to be input on a time axis;    first memory means for performing an in-frame compression coding on the video data that have been thinned out;    means for recording/playback, respectively, on/from a hard disk that reads in-frame compression coded data from the first memory means and records the read data in the hard disk;    second memory means for playing back data from the means for recording/playback, respectively, on/from a hard disk and temporarily recording the played back data; and    means for recording/playback, respectively, on/from a medium that reads as a unit a predetermined amount of the data from the second memory means and records the read data on the recording medium available to be detachably inserted into the main body of the apparatus,    wherein a special playback mode is performed with said in-frame compression coded data when the data recorded on said recording medium available to be detachably inserted into the main body of the apparatus are played back.    
   
   
       7 . A recording/reproducing apparatus for recording and reproducing digital compressed video signals on removable recording media, comprising: 
 a first memory configured to temporarily store intra-coded image data coded every m frames, with m being an integer of not less than two, of continuously inputted video signals and inter-coded image data coded from the other frames of the inputted video signals;    a first recorder/reproducer configured to alternately read n frames, with n being an integer no less than two, of the intra-coded image data and the other inter-coded image data from the first memory of a first data rate higher than an input data rate to the first memory, and record and/or reproduce the image data read from the first memory on a hard disk;    a second memory configured to temporarily store the image data reproduced from the hard disk;    a second recorder/reproducer configured to read image data from the second memory and record/reproduce the image data read from the second memory on removable recording media; and    a controller configured to control the data storing/reading operation of the first and the second memory and the recording/reproducing operation of the first and the second recorder/reproducer;    wherein the second recorder/reproducer reproduces both the intra-coded data and the inter-coded data from the removable recording media in a normal play operation mode, and reproduces only the intra-coded data from the removable recording media in a first play operation mode.    
   
   
       8 . A recording/reproducing apparatus according to  claim 7 , wherein the digital compressed video signals are coded with MPEG format.  
   
   
       9 . A recording/reproducing apparatus according to  claim 7 , wherein the continuously inputted video signals are digital image data where the number of frames per second is limited by thinning out.  
   
   
       10 . A recording/reproducing apparatus according to  claim 7 , wherein the second recorder/reproducer records the image data on the removable recording media whenever the amount of data recorded on a hard disk reaches a specified level.  
   
   
       11 . A recording/reproducing apparatus for recording and reproducing digital compressed video signals on removable recording media, comprising: 
 a memory configured to temporarily store intra-coded image data coded every m frames, with m being an integer of not less than two, of continuously inputted video signals and inter-coded image data coded from the other frames of the inputted video signals;    a recorder/reproducer configured to read image data from the memory, record the image data read from the memory on removable recording media, and reproduce both the intra-coded data and the inter-coded data from the removable recording media in a normal play operation mode, and reproduces only the intra-coded data from the removable recording media in a fast pay operation mode.    
   
   
       12 . A recording/reproducing apparatus for recording and reproducing digital compressed video signals on removable recording media, comprising: 
 a first memory configured to temporarily store intra-coded image data coded every m frames, with m being an integer of not less than two, of continuously inputted video signals and inter-coded image data coded from the other frames of the inputted video signals;    a first recorder/reproducer configured to alternately read n frames, with n being an integer no less than two, of the intra-coded image data and the other inter-coded image data from the first memory at a first data rate higher than an input data rate to the first memory and record/reproduce the image data read from the first memory on hard disks alternately; and    a second memory configured to temporarily store the image data reproduced from the hard disks alternately at the first data rate.    
   
   
       13 . A recording/reproducing apparatus according to  claim 12 , 
 wherein said first recorder/reproducer monitors volume of digital compressed video signals recorded in said hard disks and switches said hard disks based on the volume.    
   
   
       14 . A recording/reproducing apparatus according to  claim 12 , further comprising: 
 a second recorder/reproducer configured to read image data from the second memory at a second data rate lower than the first data rate and higher than the input data rate to the first memory and record/reproduce the image data read from the second memory on removable recording media; and    a controller configured to control the data storing/reading operation of the first and the second memory and the recording/reproducing operation of the first and the second recorder/reproducer,    wherein the second recorder/reproducer reproduces both the intra-coded data and the inter-coded data from the removable recording media in a normal play operation mode, and reproduces only the intra-coded data from the removable recording media in a fast play operation mode.    
   
   
       15 . An apparatus for recording/reproducing a MPEG video signal to/from hard disk drives and removable recording medium, comprising: 
 a first memory to store said MPEG video signal including intra-coded pictures, bidirectional predictive-coded pictures, and predictive-coded pictures;    a first recorder/reproducer to record an output MPEG video signal from said first memory on the hard disk drive, and to reproduce a MPEG video signal from said hard disk drives alternately; and    a second memory to store a MPEG video signal reproduced from said hard disk drives alternately.    
   
   
       16 . A recording/reproducing apparatus according to  claim 15 , 
 wherein said first recorder/reproducer monitors volume of digital compressed video signals recorded in said hard disk drives and switches said hard disk drives based on the volume.    
   
   
       17 . A recording/reproducing apparatus according to  claim 15 , further including: 
 a second recorder/reproducer to record an output MPEG video signal from said second memory on the removable recording medium, and to reproduce a MPEG video signal from said removable second recording medium;    wherein a period for storing a MPEG video signal reproduced from said hard disk drive on said second memory and recording an output MPEG video signal from said second memory on said removable second recording medium is shorter than a period for storing said MPEG video signal from said first memory on said hard disk.    
   
   
       18 . A recording/reproducing apparatus according to  claim 15 , 
 wherein the second recorder/reproducer reproduces intra-coded pictures, bidirectional predictive-coded pictures, and predictive-coded pictures from the removable recording media in a normal pay operation mode, and reproduces only the intra-coded pictures from the removable recording media in a fast play operation mode.    
   
   
       19 . An apparatus for recording/reproducing a MPEG video signal to/from a hard disk drive and removable recording medium, comprising: 
 a first memory to store said MPEG video signal including intra-coded pictures, bidirectional predictive-coded pictures, and predictive-coded pictures;    a first recorder/reproducer to record an output MPEG video signal from said first memory on the hard disk drive, and to reproduce a MPEG video signal from said hard disk drive;    a second memory to store a MPEG video signal reproduced from said hard disk drive; and    a second recorder/reproducer to record an output MPEG video signal from said second memory on the removable recording medium, and to reproduce a MPEG video signal from said removable second recording medium,    wherein a period for storing a MPEG video signal reproduced form said hard disk drive on said second memory and recording an output MPEG video signal from said second memory on said removable second recording medium is shorter than a period for storing said MPEG video signal from said first memory on said hard disk.    
   
   
       20 . The apparatus for recording/reproducing video signals, respectively, on/from a recording medium according to  claim 18 , 
 wherein an output data rate of said generator is set lower than a data rate of recording/reproducing video signals, respectively, to/from said second recording medium.    
   
   
       21 . The apparatus for recording/reproducing video signals on/from a recording medium according to  claim 18 , 
 wherein said video signal is reproduced from said first recording medium and stored on said second memory, and said output video signal from said second memory is recorded on a second recording medium each time a recording amount of said first recording medium reaches a specified value.    
   
   
       22 . The apparatus for recording/reproducing video signals on/from a recording medium according to  claim 18 , 
 wherein said video signal is recorded on said second recording medium intermittently.    
   
   
       23 . A recording/reproducing apparatus according to  claim 19 , 
 wherein the second recorder-reproducer reproduces intra-coded pictures, bidirectional predictive-coded pictures, and predictive-coded pictures from the removable recording media in a normal play operation mode, and reproduces only the intra-coded pictures from the removable recording media in a fast play operation mode.