Patent Publication Number: US-2002010833-A1

Title: Disc device

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] This invention relates to a disc device, and is applicable to, for example, a hard disc device for generating picture signals. The present invention limits retry time and sets the capacity of a buffer memory in association with this limited time to enable continuous information signals, such as picture signals, to be recorded and reproduced by an overall simplified structure.  
       [0003] 2. Description of the Related Art  
       [0004] If information signals made up of picture signals are recorded in a conventional video tape recorder, emphasis is put on data continuity in recording and/or reproducing information signals, so that, by executing interleaving or appending error correction codes, there is no risk of possible interruption of continuous data.  
       [0005] On the other hand, in a hard disc device applied to a storage device for a computer, it is verified by processing such as read-after-write or error detection, whether or not desired data have been recorded or reproduced correctly. If, in this type of the hard disc device, data cannot be recorded and/or reproduced correctly, the retry processing is repeated, or the error correction processing is executed when the necessity arises. In this type of the hard disc device, recording and/or reproducing processing is carried out in this manner with emphasis put on reliability of recorded or reproduced data.  
       [0006] If a hard disc device can be used for recording and/or reproducing of picture or speech signals, locating operations, for example, can be simplified, thus simplifying editing operations of this sort of information signals. If, in this case, picture or speech signals can be recorded or reproduced by a hard disc device for a computer, this sort of the editing device can be constructed by this component part exhibiting correspondingly advanced universality or adaptability to simplify the structure of this sort of the recording and/or reproducing apparatus.  
       [0007] However, in the hard disc device for computers, retry operations are repeated in order to put utmost emphasis on data reliability. Thus, if the hard disc device is applied to recording or reproduction of the picture or speech signals, there my be occasions wherein picture or speech signals are interrupted due to repetition of the retrial operations.  
       [0008] As a method for resolving the above inconvenience, it may be contemplated to improve reliability in the hard disc device to substantially eliminate the necessity for retry operations. However, in this case, it becomes difficult to use a general-purpose device, such as a hard disc device for a computer. Although the retry operations may be eliminated by designing even if video data cannot be reproduced correctly, it is feared in such case that uncorrectable bit errors occur frequently in the reproduced picture signals to render it difficult to reproduce continuous picture signals.  
       SUMMARY OF THE INVENTION  
       [0009] It is therefore an object of the present invention to provide a disc device capable of recording and/or reproducing continuous information signals, such as picture signals, by a structure which is simplified on the whole.  
       [0010] The present invention provides a disc apparatus for recording and/or reproducing compressed information signals for a disc-shaped recording medium via a buffer memory, wherein, if the information signals cannot be correctly recorded or reproduced for the disc-shaped recording medium, recording and/or reproducing of the information signals is re-tried within a range of a preset limit time, and wherein the buffer memory has its memory set so as to store the information signals corresponding to the limit time.  
       [0011] If recording and/or reproducing for information signals is retried within the range of a preset limit time, it is possible to reduce the occurrences of bit errors difficult to correct to a practically allowable range. If the capacity of the buffer memory is set so as to be capable of storing an amount of information signals corresponding to this limit time, the information signals, such as picture signals, can be recorded and/or reproduced without intermission, as the capacity of the buffer memory is set to a practically sufficient small value.  
       [0012] That is, by re-trying the recording and/or reproducing of information signals within a preset limit time, and by setting the capacity of the buffer memory so as to be capable of storing the volume of the information signals corresponding to this limit time, the continuous information signals can be recorded and/or reproduced without intermission, as the buffer memory is constructed to a practically sufficient small value, in order to enable the continuous information signals to be recorded and/or reproduced by a correspondingly simplified structure. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013]FIG. 1 is a block diagram showing the overall structure of an editing device embodying the present invention.  
     [0014]FIG. 2 is a block diagram showing a video signal system of a hard disc array applied to the editing device.  
     [0015]FIG. 3 is a block diagram showing an audio signal system of the hard disc array shown in FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0016] Referring to the drawings, preferred embodiments of the present invention will be explained in detail.  
     [0017]FIG. 1 shows a block diagram showing an editing device embodying the present invention. This editing device  1  records sequentially inputted video signals V 1  and audio signals A 1  on a hard disc array  2 , while editing and outputting the recorded video signals V 1  and audio signals A 1 .  
     [0018] Specifically, the editing device  1  has a controller  3 , configured as a computer, and is designed so that the operation of the entire structure is switched to record sequentially inputted video signals V 1  and audio signals A 1 , under control by the controller  3 , by actuating a mouse  3 B or a keyboard  3 C in accordance with a graphical user interface (GUI) displayed on a monitor device  3 A. Also, monitor pictures, such as video signals of the recorded video signals V 2  or V 3 , are furnished to a user, while an editing list is prepared in accordance with actuations by the user and video and audio signals recorded on the hard disc array  2  are reproduced and outputted in accordance with the prepared editing list.  
     [0019]FIG. 2 is a block diagram showing a video signal processing system of the hard disc array  2 . In this hard disc array  2 , a video data input/output unit  10  converts the video signals V 1  entered to this editing device  1  into digital video signals DV 1  of a predetermined format to output the digital video signals DV 1  to a video data processing unit  11 . Also, a video data input/output unit  10  converts the digital video signals DV and DV 3 , outputted by the video data processing unit  11 , into video signals V 2  and V 3 , which are analog signals. These video signals V 2  and V 3  are outputted to the controller  3  and to external equipments  
     [0020] This editing device  1  is configured for inputting/outputting composite video signals. In the video data input/output unit  10 , a decoder  10   a  converts the video signals V 1  composed of composite video signals into component video signals, which are outputted. These component video signals are A/D are converted by an analog/digital converting circuit (A/D converter)  10   b  to output digital video signals DV 1  of a predetermined format composed of luminance data and chroma data.  
     [0021] The digital/analog converting circuit (D/A converter)  10   c  digital/analog converts the digital video signals DV 2 , outputted by the video data processing unit  11 , by digital/analog conversion, in order to output component video signals made up of luminance signals and chroma signals. These component video signals, outputted by the D/A converter  10   c,  are converted by an encoder  10   d,  arranged next, into output composite video signals V 2 . Similarly, a digital/analog converting circuit (D/A converter)  10   e  digital/analog converts the digital video signals DV 3 , outputted by the video data processing unit  11 , by digital/analog conversion, in order to output the component video signals. These component video signals, outputted by the D/A converter  10   c,  are converted by an encoder  10   f,  arranged next, into output composite video signals V 3 .  
     [0022] The video data processing unit  11  compresses the digital video signals DV 1  inputted by the video data input/output unit  10  to output the resulting compressed signals to a system controller  12 . The video data processing unit  11  also expands video data inputted from the system controller  12  to generate digital video signals DV 2  and DV 3  which are outputted to the video data input/output unit  10 .  
     [0023] That is, in the video data processing unit  11 , a compression circuit  1 a compresses digital video signals DV 1  under the MPEG (Moving Picture Experts Group) standard to generate video data D 1  which is outputted to a buffer  11   b  at a preset data transfer speed Rv (Mbyte/sec). Also, in the video data processing unit  11 , an expansion circuit  11   c  receives video data D 2  compressed by the MPEG standard via buffer  11   b  at a preset data transfer rate Rv and expands this video data D 2  to output the digital video signals DV 2 .  
     [0024] The buffer  11   b  is constituted by a memory of the FIFO (first-in first-out) circuit configuration and has its operation switched under control by the system controller  12 . Specifically, the buffer  11   b  outputs the video data D 1  entered from the compression circuit  11   a  to the system controller  12 , while outputting the video data DS fed from system controller  12  and outputting the video data inputted from the compression circuit  11   a  in place of the video data inputted from the system controller  12  to the expansion circuit  11   c.  Thus, the buffer  11   b  is configured to record video data on plural hard discs  13 , monitor the video data recorded on these plural hard discs  13  and to monitor compressed video data D 1  of the sequentially inputted video signals V 1  as the occasion may demand.  
     [0025] When inputting/outputting the video data DS in this manner, the buffer  11   b  inputs/outputs the video data D 1  and D 2  between it and the compression circuit  11   a  or the expansion circuit  11   c  at a data transfer rate Rv (Mbyte/sec) corresponding to the data processing speed of the compression circuit  11   a  and the expansion circuit  11   c,  while inputting/outputting the video data DS between it and the system controller  12  at a data transfer rate Rh (Mbyte/sec) higher than the data transfer rate Rv (Mbyte/sec). Thus, the buffer  11   b  inputs/outputs the video data D 1  and D 2  between it and the system controller  12  or the expansion circuit  11   c  substantially continuously, while inputting/outputting the video data DS between it and the system controller  12 .  
     [0026] The buffer  11   b  has its capacity B (Mbyte) set to a practically small enough value satisfying the following relation: 
       B&gt;Tr×Rv   (1) 
     [0027] where Rv is the data transfer rate (Mbyte/sec) between it and the compression circuit  11   a  or the expansion circuit  11   c  and Tr is the retry limit time which will be explained subsequently. In the editing device  1 , the buffer  11   b  is configured to store the video data D 1  outputted by the compression circuit  11   a  with this retry limit time to enable the video data DS to be recorded or reproduced without interruptions with the necessary minimum capacity.  
     [0028] Similarly to the buffer  11   b , the buffer  11   d  is constituted by a memory of a FIFO circuit configuration adapted to hold the video data DS entered from the system controller  12  and which outputs the video data DS thus held to an expansion circuit  11   e  at a data transfer rate Rv corresponding to the data processing speed of the expansion circuit  11   e.  Similarly to the buffer  11   b , the buffer  11   d  has the data transfer rate Rh (Mbyte/sec) and the data transfer rate Rv (Mbyte/sec) set between it and the system controller  12  and between it and the expansion circuit  11   e,  respectively, while having its capacity B set to a sufficiently small value for practical use for these data transfer rates Rh, Rv (Mbyte/sec) insofar as the equation (1) is met. Thus, in the editing device  1 , the buffer  11   d  is configured for storing the video data D 3  to be sent to the expansion circuit  11   e  with the retry limit time Tr.  
     [0029] The expansion circuit  11   e  expands the video data DS outputted by this buffer  11   d.    
     [0030] The system controller  12  inputs/outputs a control command, for example, between it and the controller  3 , in accordance with the communication format of RS-422, and executes a series of processing operations by a central processing unit (CPU)  12   a  in accordance with the control command. Thus, the system controller  12  controls the entire operation of the hard disc array  2 .  
     [0031] In this system controller  12 , a direct memory access controller (DMA)  12   b  has its operation switched under control by the central processing unit  12   a  in order to input/output data between it and the video data processing unit  11  and in order to output the video data between it and the small computer system interface (SCSI) controller  12   c.  The direct memory access controller  12   b  at this time controls the timing of the video data DS inputted from the video data processing unit  11 , while controlling the timing of the video data DS inputted from the SCSI controller  12   c  to output the video data DS to the video data processing unit  11 .  
     [0032] The SCSI controller  12   c  issues a control command to the plural hard discs  13  allocated to the recording of video signals, under control by the central processing unit  12   a,  while allocating and recording the video data DS inputted from the direct memory access controller  12   b  in a distributing fashion in these plural hard discs  13  and reproducing the video data DS from these hard discs  13  to output the reproduced data to the direct memory access controller  12   b.    
     [0033] In the SCSI controller  12   c,  if a preset volume of the video data DS is stored during recording in the buffer  11   b , the video data DS is fed from the buffer  11   b  via the direct memory access controller  12   b  so as to be recorded on the hard disc  13 . The SCSI controller  12   c  then causes the video data DS to be read out intermittently from the buffer  11   b  to record the read-out video data DS on the hard disc  13  to secure a preset vacant area in the buffer  11   b.    
     [0034] Similarly, when the vacant areas in the buffers  11   b ,  11   d  are decreased during reproduction to less than a preset value, the hard disc  13  intermittently drives the hard disc  13  to output the video data DS to prevent interruption of the video data DS outputted to the expansion circuits  11   c ,  11   e.    
     [0035] Under control by the SCSI controller  12   c , the hard disc  13  records the sequentially inputted video data DS or reproduces the recorded video data DS to output the reproduced data. During recording of the video data, the hard disc  13  records the video data DS as it appends predetermined error correction code to execute the read-after-write processing. At this time, the hard disc repeats the retry processing operations within the previously set number of times of limitation.  
     [0036] It is noted that the number of times of retry operations is set to a value such that, even in such cases wherein it is difficult to record the video data DS correctly, the correct video data DS can be reproduced by error correction by the error correction codes. In the present embodiment, the above-described limitation time Tr is set such that retry is repeated within this limited number of times and retry processing comes to a close within the extent of the retry limit time Tr.  
     [0037] It is thus possible with the editing device  1  to set the capacity of the buffer  11   b  to a sufficiently small value B for practical application and to reduce the occurrence of bit errors difficult to correct to a sufficiently low range for practical application to enable uninterrupted recording of the video signals V 1 .  
     [0038] If, during reproduction, the video data DS cannot be reproduced correctly by the error detection processing, the hard disc  13  repeats the retry processing within a range of similar number of times of limitation. It is noted that the number of times of retry at the time of reproduction is set to a value such as to enable correct video data DS to be reproduced by error correction by the error correction codes. In the present embodiment, retry operations are repeated within the range of the limit time Tr by this setting of the number of times of limitation.  
     [0039] Thus, the editing device  1  can set the capacities of the buffers  11   b ,  11   c  to a sufficiently small value B for practical application to reduce the occurrence of bit errors difficult to correct in order to enable the video signals V 1  to be reproduced without interruptions.  
     [0040]FIG. 3 shows a block diagram showing the processing system of audio signals of the hard disc array  2 . In this hard disc array  2 , an audio data input/output unit  15  converts the audio signal A 1  inputted to this editing device  1  into digital audio signals DA 1  of a predetermined format to output the digital audio signals DA 1  to an audio data processing unit  16 . On the other hand, the audio data input/output unit  15  converts the digital audio signals DA 2  outputted by the audio data processing unit  16  into analog audio signals A 2  which are outputted to the controller  3  and to an external equipment.  
     [0041] That is, a decoder  15   a  in the audio data input/output unit  15  converts the analog audio signals A 1  to signals of a format suited for the next following digital signal processing to output the resulting signals. In an analog/digital converting circuit (A/D converter)  15   b,  next following the decoder  15   a,  the audio signals are analog/digital converted to generate the digital audio signals DA 1  of the predetermined format, which signals DA 1  are outputted.  
     [0042] The digital audio signals DA 2 , outputted by the audio data processing unit  16 , are digital/analog converted by a digital/analog converting circuit (D/A converter)  15   c  so as to be outputted as audio signals. The audio signals, outputted by the digital/analog converting circuit  15   c,  are converted by an encoder  15   d,  next following the digital/analog converting circuit  15   c,  into analog audio signals A 2  of a predetermined format which are outputted.  
     [0043] An audio signal processor  16  compresses the digital audio signals DA 1 , sent from the audio data input/output unit  15 , to output the resulting data to the system controller  12 . The audio data processing unit  16  also expands the audio data entered from the system controller  12  to generate digital audio signals DA 2  which are outputted to the audio data input/output unit  15 .  
     [0044] That is, in the audio data processing unit  16 , a compressing circuit  16   a  compresses the digital audio signals DA 1  to generate audio data AD 1  which is outputted to a buffer  16   b  at a preset data transfer rate Rva (Mbyte/sec).  
     [0045] The buffer  16   b  is constituted by a memory of the FIFO circuit structure and has its operation switched under control by the system controller  12 . That is, the buffer  16   b  outputs the analog audio data AD 1  sent from the compressing circuit  16   a  to the system controller  12 , while outputting the audio data sent from the system controller  12  to an expansion circuit  16   d.  Thus, the buffer  16   b  is configured for recording audio data on plural hard discs  17  via system controller  12  and for monitoring audio data recorded on these hard discs  17 .  
     [0046] In inputting/outputting audio data DAS, the buffer  16   b  is fed with the audio data AD 1  at the data transfer rate Rva (Mbyte/sec) corresponding to the data processing rate of the compressing circuit  16   a,  while it inputs/outputs the audio data DAS between it and the system controller  12  at a data transfer rate Rha (Mbyte/sec) higher than the data transfer rate Rva (Mbyte/sec). Thus, the buffer  16   b  inputs/outputs audio data AD 1  substantially continuously between it and the compressing circuit  16   a,  while intermittently inputting/outputting audio data DAS between it and the system controller  12 .  
     [0047] The buffer  16   b  has its capacity Ba (Mbyte/sec) set to a sufficiently small value for practical application with respect to the data transfer rate Rva (Mbyte/sec) within a range of the following relation: 
       Ba&gt;Tra×Rva   (2) 
     [0048] where Tra is the limit time which is the same as the retry limit time of the above-mentioned hard disc  13 . This enables the editing device  1  to record continuous audio data DAS within the range of the necessary minimum capacity without intermission.  
     [0049] Similarly to the buffer  16   b,  the buffer  16   c  is constituted by a memory of the FIFO circuit configuration, and holds the audio data DAS entered from the system controller  12 , while outputting the audio data DAS it holds to the expansion circuit  16   d  at a data transfer rate Rva corresponding to the data processing speed of the expansion circuit  16   d.  Similarly to the buffer  16   d,  the buffer  16   c  has its data transfer rate Rha (Mbyte/sec) and the data transfer rate Rva (Mbyte/sec) set with respect to the system controller  12  and to the expansion circuit  16   d . Moreover, the buffer  16   c  has its capacity Ba set to a sufficiently small capacity Ba for practical application in relation to the data transfer rates Rha and Rva (Mbyte/sec) within a range satisfying the relation (2).  
     [0050] The expansion circuit  16   d  expands the audio data DAS outputted by this buffer  16   c  to output digital audio signals.  
     [0051] In the present audio signal processing system, the system controller  12  performs switching control of the entire operation in synchronism with the video system under control by the central processing unit  12   a.    
     [0052] That is, in the present system controller  12 , the direct memory access controller (DMA)  12   d  switches the operation under control by the central processing unit  12   a  to input/output audio data DAS between it and the audio data processing unit  16 , while inputting/outputting the audio data DAS between it and the SCSI controller  12   e.  The direct memory access controller  12   d  at this time controls the timing of the audio data DAS entered from the audio data processing unit  16  to output the audio data DAS to the SCSI controller  12   e,  while controlling the timing of the audio data DAS entered from the SCSI controller  12   e  to output the resulting data to the audio data processing unit  16 .  
     [0053] The SCSI controller  12   e  issues control commands to plural hard discs  17  allocated for recording audio signals, under control by the central processing unit  12   a , to record the audio data DAS sent from the direct memory access controller  12   d  in a distributed fashion on the plural hard discs  17 . Also, the SCSI controller  12   e  reproduces the audio data DAS from the plural hard discs  17  to output the reproduced data to the direct memory access controller  12   d.    
     [0054] If, during recording, a preset data volume of the video data DS is stored in the buffer  11   b , the SCSI controller  12   e  intermittently inputs the audio data DAS from the buffer  16   b  via the direct memory access controller  12   d , under control by the central processing unit  12 , in order to receive the audio data DAS intermittently from the buffer  16   b  via the direct memory access controller  12   d  and in order to record the input audio data DAS on the hard disc  17 . Similarly, during reproduction, the SCSI controller  12   e  intermittently drives the hard disc  17  to reproduce audio data DAS so that there is no risk of intermission of the audio data DAS outputted by the buffer  16   c  to the expansion circuit  16   d.    
     [0055] The hard disc  17  records the sequentially entered audio data DAS, under control by the SCSI controller  12   e,  while reproducing and outputting the recorded audio data DAS. During recording of the audio data, the hard disc  17  appends preset error correction codes to the audio data DAS being recorded to execute the read-after-write processing. If it has been detected by this read-after write that recording of audio data has resulted in failure, retry processing is repeated. At this time, the hard disc  17  repeats retry processing within a range of a previously set number of times of limitation.  
     [0056] The number of times of retry is set so that, even if it is difficult to record the audio data DAS correctly, correct audio data can be reproduced on error correction by error correction codes. In the present embodiment, retry processing is adapted to be repeated within the range of the limit time Tr subject to this setting of the number of times of limitation.  
     [0057] Thus it is possible with the editing device  1  to set the capacity of the buffer  16   b  to a sufficiently small value for practical application to reduce the occurrences of the bit errors difficult to correct to a practically tolerable level to render it possible to record the audio signal A 1  without intermission.  
     [0058] If it has been found on error detection at the time of reproduction that recording of the audio data DAS has resulted in failure, retry processing is performed within the similar range of the number of times of limitation. It is noted that the number of times of the retry processing at the time of reproduction is set so that correct audio data DAS can be reproduced by error correction by the error correction code. In the present embodiment, the retry processing is repeated within the number of times of limitation so that the reproducing processing will be completed within the limit time Tr.  
     [0059] It is thus possible with the editing device  1  to set the capacity of the buffer  16   c  to a sufficiently small value Ba to reduce the occurrence of bit errors difficult to correct to a sufficiently small range for practical application to enable the analog audio signals A 2  to be reproduced without intermission.  
     [0060] In the above-described editing device  1 , shown in FIG. 1, the video signals V 1  and the audio signals A 1 , sequentially entered, are recorded on the hard disc array  2  and the video signals V 2 , V 3  and the audio signals A 2  recorded on the hard disc array  2  are reproduced and displayed on a monitor  3 A, subject to actuation by an operator. The video signals V 2 , V 3  and the audio signals A 2  recorded on the hard disc array  2  are reproduced and outputted to an external equipment in accordance with an editing list which the operator has set on monitoring the display on the monitor  3 A.  
     [0061] Of the video signals V 1  to V 3  (FIG. 2) and audio signals, recorded or reproduced in this manner, the video signal V 1 , sequentially entered, is converted by a decoder  10   a  of the video data input/output unit  10  into component video signals and subsequently converted by the next following digital/analog converter  10   b  into a digital video signal DV 1 . This digital video signal DV 1  is compressed by the compression circuit  11   a  of the video data processing unit  11  to generate video data Digital audio signals DA 1  which are sequentially stored in the buffer  11   b  at a data transfer rate Rv (Mbyte/sec).  
     [0062] This video data Digital audio signal DA 1  is farther sent to the system controller  12  from the buffer  11   b  so as to be recorded by this system controller  12  in a distributed fashion in plural hard discs  13 . The video data digital audio signals DA 1  is intermittently read out from the buffer  11   b  at a data transfer rate Rh (Mbyte/sec) higher than the transfer rate at the time of inputting to the buffer  11   b  for recording on the plural hard discs  13 , so that the buffer  11   b  is not subjected to overflowing and so that a predetermined vacant capacity is secured in the buffer  11   b.    
     [0063] In each hard disc  13 , an error correction code is appended to the video data, so that, in recording the video data, it is checked, by read-after-write and error detection, whether or not recording has been made correctly. If correct recording has not been made, retry processing is repeated within the range of the preset number of times of limitation so that the video data is recorded on the hard disc  13  within the time of limitation. If the number of times of limitation is set to a value which will allow for correct reproduction of the video data DS by error correction employing the error correction code, the video data DS is recorded on each hard disc  13  so that occurrence of bit errors difficult to correct at the time of reproduction will be reduced to a level sufficient low for practical application.  
     [0064] With the editing device  1 , the video data Digital audio signals DA 1  is stored in succession in the buffer  11   b  by this retry processing in excess of the usual vacant capacity which prevails in the absence of the retry processing. If the retry processing comes to a close, the video data D 1  are sequentially stored in succession in the hard disc  13  so that the vacant capacity of the buffer  11   b  will be of a preset value. Since the capacity of the buffer  11   b  is set with respect to the limit time Tr by the number of times of limitation of retry and the data transfer rates Rh, Rv so that the relation (1) is met, overflow of the buffer  11   b  can be effectively prevented from occurring even on repetition of retry processing. The buffer  11   b  can be constructed with a sufficiently small capacity for practical application, so that continuous video signals can be recorded without intermission with a correspondingly simple structure.  
     [0065] During reproduction, the video data DS are reproduced from the hard disc  13  under control by the system controller  12  so as to be entered via buffers  11   b ,  11   d  to the expansion circuits  11   c  and  11   e.  The video data D 2 , D 3  are expanded to generate digital video signals DV 2 , DV 3 , which are converted into output analog composite video signals V 2 , V 3 .  
     [0066] These video data are outputted from the buffers  11   b ,  11   d  at the data transfer rate Rv corresponding to the processing rate in the expansion circuits  11   c,    11   d , while being sent to the buffers  11   b ,  11   d  at the data transfer rate Rh (Mbyte/sec) higher than the data transfer rate Rv. It is noted that the video data are intermittently reproduced from the hard disc  13  and sent to the buffers  11   b ,  11   d  so that no overflow will occur in the buffers  11   b ,  11   d  and so that video data D 2 , D 3  in excess of a pre-set value will be held in the buffers  11   b ,  11   d.    
     [0067] Also, it is checked, by the error detection processing in the hard disc  13 , whether or not reproduction has been made correctly. If reproduction has not been made correctly, retry processing is repeated within a range of the preset number of times of limitation so that the video data are reproduced within the limit time Tr. Since the number of times of limitation is set to a value such that correct video data DS can be reproduced by error correction by the error correction code, the occurrence of bit errors difficult to correct is reduced to a sufficiently low level for practical application as the video data DS are reproduced from each hard disc  13 .  
     [0068] In the editing device  1 , the continuous video data D 1  are sequentially reproduced from the hard disc  13  so as to be stored in the buffers  11   b ,  11   b , so that, as a result of the retry processing, the volume of data of the video data D 3  stored in the buffers  11   b ,  11   d  will be reduced to lower than the usual data volume, which is the data volume prevailing in the absence of the retry processing, and so that, when the retry processing comes to a close, the data volume will be of a preset value.  
     [0069] With the editing device  1 , in which the capacity B of the buffers  11   b ,  11   d  is set so as to satisfy the relation (1) for the limit time Tr corresponding to the number of times for retry limitation and the data transfer rates Rh, Rv, the video data D 2 , D 3  can be supplied without intermission to the expansion circuits  11   c,    11   e  even if retry processing is repeated, whereby the video signals can be outputted without intermission from the editing device  1 . By constructing the buffers  11   b ,  11   d  with a sufficiently small capacity B for practical application, continuous video signals can be reproduced without intermission by a correspondingly simplified structure.  
     [0070] On the other hand, audio signals A 1  (FIG. 3) are converted by an analog/digital converting circuit  15   b  of the audio data input/output unit  15  into digital audio signals DA 1  which are compressed in the next following compressing circuit  16   a  of the audio data processing unit  16  to generate audio data AD 1 . These audio data AD 1  are sequentially stored in the buffer  16   b  at a data transfer rate Rva (Mbyte/sec) so as to be recorded via system controller  12  in the hard disc  17  allocated for audio signals.  
     [0071] Conversely, the audio data DAS reproduced from the hard disc  17  are stored via system controller  12  in the buffer  16   e  and expanded by the next following expansion circuit  16   d . These expanded data are converted by the audio data input/output unit  15  into output analog signals.  
     [0072] In the inputting/outputting for the buffers  16   b,    16   c  in the editing device  1 , the retry time of the hard disc  17  is limited by the number of times of retry and the capacities of the buffers  16   b ,  16   c  are set to values sufficient to meet the relation (2) within this range of limitation. It is thus possible to construct the buffers  16   c ,  16   d  to a sufficiently small capacity B for practical application to record/reproduce continuous audio signals without intermission.  
     [0073] In the above arrangement, in which the retry time for the hard discs  13 ,  17  is limited by the number of times of retry and in which the capacities of the buffers  11   b ,  11   d ,  16   b ,  16   c  are set in such a manner as to store the amount of the video and audio data corresponding to this limit time, it is possible to construct the buffers  11   b ,  11   d ,  16   b ,  16   c  with a sufficiently small capacity B for practical application to record/reproduce audio signals without intermission. The result is that video and audio signals can be recorded and/or reproduced by a correspondingly simpler overall structure.  
     [0074] Although the retry time of the hard discs  13 ,  17  is limited in the above embodiment by the number of times of retry limitation, the present invention is not limited to this illustrative structure and the retry time can be directly limited by time management.  
     [0075] In the above embodiment, the retry time of the hard discs  13 ,  17  is limited by the number of times of retry limitation. The present invention, however, is not limited to this embodiment and can be broadly modified so that retry limit time will be set to various different values as the occasion may demand. That is, there are occasions wherein data restoration can be achieved to an extent practically sufficient by, for example, interpolation. In such case, the retry limit time can be reduced to a shorter value.  
     [0076] In the above-described embodiment, the retry limit time is set by the previously set number of times of retry. The present invention, however, is not limited to this embodiment since the retry limit time can be varied as the occasion may demand. Specifically, if once the retry processing is executed, the time T:  
             T   =     B     Rh   -   Rv               (   3   )                       
 
     [0077] is required after executing the retry until the buffer contents are charged with video data. Thus, during this time T, the retry time can be limited by this time T instead of by the limit time Tr and the limit time Tra to secure continuity of the video data during this time T.  
     [0078] In the above-described embodiment, information signals composed of the video and audio signals are recorded and/or reproduced by the hard disc device. The present invention, however, is not limited to this embodiment and can be broadly applied to the cases of recording or reproducing information signals composed of video and audio signals for a variety of disc-shaped recording mediums, such as optical discs.