Abstract:
A method and apparatus for recording control for a recording medium having a data recording region for recording data such as audio data, speech data, and a control data region for recording control data for the data recording region. The method and apparatus includes identifying a non-silent recorded portion and a silent recorded portion of the data recorded in the data recording region based upon the signal level of the data recorded in the data recording region, and recording control data for separating the data recorded in the data recording region into temporally former and temporally latter portions at a boundary portion between the non-silent recorded portion and the silent recorded portion based upon the results of the identification after recording of the data in the data recording region has ended.

Description:
This is a divisional of application Ser. No. 08/319,258, filed Oct. 6, 1994 now U.S. Pat. No. 5,719,837. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to an apparatus for recording on a recording medium and a method for controlling the recording process. More particularly, the present invention relates to a recording apparatus for recording on a recording medium under control based on the data signal level, and a method for controlling the recording process. 
     2. Background of the Invention 
     An optical disc may have a recording capacity two to three orders of magnitude larger than a magneto-optical disc, and permits higher speed access than with a tape-shaped recording medium. Since the optical disc also has such merits as high durability and contact-free data recording/reproduction, it has recently being employed in increasing numbers. 
     There are several types of optical discs, such as a read-only optical disc having a read-only area with data recorded as pits, conforming to a standard CD (Compact Disc) format, referred to hereinafter as a CD-DA format, a magneto-optical disc, in the form of a magneto-optical recording medium having a recording/reproducing area conforming to a CD-MO format as an extension format of the CD-DA format, and a hybrid disc having both the read-only area with data recorded as pits and a recording/reproducing area having a magneto-optical recording layer in which the data is recorded on or reproduced from the magneto-optical recording layer. 
     If, in a data recording/reproducing apparatus for recording data on a disc-shaped recording medium, such as a magneto-optical disc or a hybrid disc, the recording data become useless data during recording, the recording is discontinued by a manual operation. If a song or other audio program are to be recorded from a CD to a magneto-optical disc, the recording by the magneto-optical disc recording/reproducing apparatus is discontinued by a manual operation after the end of reproduction by the CD player. 
     In a disc-shaped recording medium, such as an optical disc or a magneto-optical disc, there are provided a main data recording area for recording main data, such as audio data or speech data or general data, and a control data recording area for recording control data. 
     In the data recording/reproducing apparatus for the disc-shaped recording medium, the pre-recorded area and the non-recorded recordable area are controlled by control data recorded in the control data recording area. For example, in the optical disc conforming to the CD-DA format, the recording start address information and the recording end address information are sequentially recorded for all of the program data in a lead-in region as a table-of-contents (TOC) information indicating the recording position and the recording contents of the data region. 
     The present Assignee has already proposed a recording and/or reproducing apparatus for digitally recording and/or reproducing audio signals or music signals or the like using an optical disc of substantially 64 mm in diameter housed within a disc cartridge. This type of the optical disc may be classified into a read-only optical disc, a recordable disc such as a magneto-optical disc and a hybrid disc having both the read-only region and the recordable region. In the magneto-optical disc capable of data recording and reproduction, the program region and the U-TOC region (user TOC region) are provided in the recordable region, and the TOC data indicating the recording position and the recording contents of the program region, referred to herein as U-TOC data, are recorded in the U-TOC region. 
     With such disc recording/reproducing apparatus, the recording is discontinued by a manual operation. As a result, if only songs or programs, such as audio or music data are, designated using the program reproduction function of the CD player to be recorded, and a song or program smaller in data quantity than the capacity of the recording side is reproduced, a silent recorded portion, such as a portion recorded zero-level audio data, is produced on the end after the end of the reproduction on the source side. In order to prevent the silent portion from being recorded on end, it is necessary to watch the state of the source and to terminate recording as soon as the reproduction of the source side comes to a close. 
     On the other hand, if recording is not discontinued by a manual operation, the silent portion continues to be recorded up to the end of the recordable region, such that, unless the silent portion is re-registered as a vacant region, recording cannot be made in succession to the recorded portion. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an apparatus for recording on a recording medium which resolves the above-mentioned problems. 
     It is another object of the present invention to provide a method for recording control on a recording medium which resolves the above-mentioned problems. 
     According to the present invention, there is provided a recording apparatus for recording data on a recording medium having a data recording region for recording data and a control data region for recording control data for the data recording region. The apparatus includes a time measurement unit which measures the time during which the signal level of data recorded in the data recording region is below a pre-set level, and recording controller discontinues data recording on the recording medium when the time measured by the time measurement unit exceeds a pre-set time duration, and recording control data in the control data region for separating portions of the data recorded in the data recording region beginning from a time point preceding a pre-set time from the end of the data recorded in the data recording region up to the end of the recorded data as being another data. 
     According to the present invention, there is provided an apparatus for recording on a recording medium having address data pre-recorded thereon and also having a data recording region for recording data based upon the address data and a control data region for recording control data for the data recording region. The apparatus includes a storage unit and a recording controller. The storage unit stores an address when the signal level of the data recorded in the data recording region becomes lower than a pre-set level. The recording controller records control data in the central region for separating data downstream of the address stored in the storage unit as other data, based upon the address data stored in the storage unit after recording of the data in the data recording region has ended. 
     According to the present invention, there is provided an apparatus for recording on a recording medium having a data recording region for recording data and a control data region for recording control data for said data recording region. The apparatus includes a time measurement unit and a recording controller. The time measurement unit measures the time during which the signal level of data recorded in the data recording region is below a pre-set level. The recording controller discontinues data recording on the recording medium when the time measured by the time measurement unit exceeds a pre-set time duration and records control data in the control data region for separating data recorded in the data recording region into at least two data portions on either side of the time when a pre-set time has elapsed since a time point at which the data level has become lower than the pre-set level. 
     According to the present invention, there is provided a recording method for recording data on a recording medium having a data recording region for recording data and a control data region for recording control data for the data recording region. The method includes identifying a non-silent recorded portion and a silent recorded portion of the data recorded in the data recording region based upon the signal level of the data recorded in the data recording region, and recording control data in the central data region for separating the data recorded in the data recording region into temporally former and temporally latter portions at a boundary portion between the non-silent recorded portion and the silent recorded portion based upon the results of the identification after recording of the data in the data recording region has ended. 
     According to the present invention, the recording operation is automatically discontinued at a time point when a pre-set time has elapsed since the time when the data signal level has become lower than a pre-set level, on the basis of the signal level of data recorded in the data recording region of the recording medium, and control data is recorded in the control data region so that data recorded in the data recording region from the time the data signal level has become lower than the pre-set level will be separated as another data. This enables data recording on the recording medium to be discontinued, while enabling the data recording region on the recording medium to be utilized effectively. 
     According to the present invention, address data is stared at a time point where the data signal level has become lower than a pre-set level on the basis of the signal level of data recorded in the data recording region of the recording medium having pre-recorded address data thereon and control data is recorded after the end of recording on the recording medium on the basis of the stored address data so that data recorded in the data recording region from the stored address data may be taken as another data. This enables the data recording region of the recording medium to be utilized effectively, while enabling data recorded in the data recording region to be separated into the non-silent data portion and the silent data portion automatically. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more readily understood with reference to the accompanying drawings, wherein: 
     FIG. 1 is a block diagram showing an arrangement of the disc-shaped recording and/or reproducing apparatus embodying the present invention; 
     FIG. 2 illustrates a disc employed in the disc-shaped recording and/or reproducing apparatus shown in FIG. 1; 
     FIG. 3 illustrates the construction of a sector  0  of the U-TOC of a recording/reproducing region of the disc; 
     FIG. 4 illustrates the construction of a sector  1  of the U-TOC of a recording/reproducing region of the disc; 
     FIG. 5 illustrates the construction of a sector  2  of the U-TOC of a recording/reproducing region of the disc; 
     FIG. 6 is a flow chart showing a recording control of a system controller of the disc-shaped recording and/or reproducing apparatus shown in FIG. 1; and 
     FIG. 7 is a flow chart showing another recording control of a system controller of the disc-shaped recording and/or reproducing apparatus shown in FIG.  1 . 
    
    
     DESCRIPTION OF THE INVENTION 
     Referring to the drawings, the recording apparatus for a recording medium and the method for controlling the recording will be explained in detail. In the following description, a disc recording and/or reproducing apparatus employing a disc-shaped recording medium is taken as an example. 
     The recording and/or reproducing apparatus according to the present invention is arranged and constructed as shown in a block diagram shown in FIG.  1 . 
     The disc recording/reproducing apparatus, shown in FIG. 1, has a disc  11   b  of 64 mm in diameter, which is housed within a disc cartridge  11   a  and which is rotationally driven at a constant linear velocity (CLV) by a spindle motor  12  for data recording and/or reproduction. For example, a hybrid disc  11   b  having a read-only region A 10  and a recording/reproducing region A 20  provided outside of the read-only region A 10 , as shown in FIG. 2, is rotationally driven at CLV by the spindle motor  12 . 
     The read-only region A 10  of the hybrid disc  11   b  has a program region A 11  having program data, such as play data, recorded therein, and a lead-in region A 12  provided inwardly of the program region A 11 . In the read-only region A 10 , digital data are pre-recorded as the presence or absence of pits as physical projections and recesses. In the lead-in region A 12 , various control data, such as start and end addresses, track or program names, and a disc name are sequentially recorded as TOC data for indicating the recording position or recording contents of all of the program data. 
     The recording/reproducing region A 20  of the hybrid disc  11   b  has a program region A 21  for recording the program data, such as play data, and a U-TOC region A 22  provided inwardly of the program region A 21 . The recording/reproducing region A 20  is formed of a magneto-optical recording medium. The recording/reproducing region A 20  has a recording track extending along a groove formed as a tracking guide groove. The groove is wobbled for recording a spindle motor  12  controlling sine wave signal as a wobbling signal. The sine wave signal is also frequency modulated for superimposing the address information on the sine wave signal. In the U-TOC region A 22 , various control data, such as track numbers indicating a series of data recorded in the program region and the positions of the respective regions are recorded as U-TOC data, indicating the recording positions and recording contents of data recorded in the program region. 
     In the U-TOC region A 22 , the recording/reproducing region for three sectors, that is sectors  0 ,  1  and  2 , are allocated in the U-TOC region A 22 . 
     In the sector  0  of the U-TOC region A 22 , the recording state of the disc  11   b  is recorded, as shown in FIG. 3. A byte P-FRA is used for controlling the recordable region of the disc  11   b . In this byte P-FRA, there is recorded a pointer on the sector  0  in which there is a start address indicating the start address of the recordable region. A byte P-TNOn controls the pre-recorded region in the program region A 121 . In a byte P-TNO- 1 , there is recorded a pointer on the sector  0  in which there is an address of a start position of the first music data. That is, if there is “1” in the byte P-TNO 1 , the start and end addresses are recorded, starting at (76+1×2)×4 byte of the sector  0  as a leading end. The same holds for a byte P-TNO 2  and so forth. 
     The sector  1  of the U-TOC region A 22  is constructed as shown in FIG.  4 . In this sector  1 , there is recorded the information concerning the disc name and the track name. These disc and track names are recorded in the ASCII code. In a byte P-TNA 1 , there is recorded the leading address on the sector  1  in which there is recorded the track name of the first music data. If the byte P-TNA 1  is “2”, the track name of the first music data is recorded with the (76+2×2)×4 byte of the sector  1  as the leading end. The same holds for a byte P-TNA 2  and so forth. 
     The sector  2  of the U-TOC region A 22  is constructed as shown in FIG.  5 . The sector  2  is reserved for recording the time and date on which the program recording was made. With the disc recording and/or reproducing apparatus, the recording time and data are automatically recorded simultaneously with the recording of each program. In a byte P-TRD 1 , there is recorded the leading address on the sector  2  in which there is the recording time and date for the first air. That is, if the byte P-TRD 1  is “3”, there is recorded data concerning the recording time and date for the first air with the (76+3×2)×4 byte of the sector  2  as the leading position. The same holds for a byte P-YDR 2  and so forth. The program recording time and date on the disc is recorded with the 76×4 byte of the sector  2  as the leading position. 
     It is noted that the information Link-P is contained in each track information of the sectors  0  and  1  of the U-TOC region A 22 . In the sector  0 , this byte Link-P indicates, when a program is divided into plural small regions and discretely recorded in this state in the disc  11   b , whether or not there is a small region directly following the previous small region. If such a small region exists, the byte Link-P indicates the information P-TNOn. In the sector  1 , this byte Link-P indicates where the name of the program is linked next. Consequently, even if the program is erased, two programs are combined together, or the number of letters of the track name is subsequently increased, it is possible to cope with such a situation by employing the information Link-P. 
     With the present disc recording and/or reproducing apparatus, audio data is magneto-optically recorded along the recording track of the recording/reproducing region A 20  of the disc  11   b  by radiating a light beam by, for example, an optical pickup  13 , on the disc  11   b  rotated at the CLV by the spindle motor  12  and simultaneously applying a vertical magnetic field modulated in accordance with the recording data by a magnetic head  10 . In addition, the audio data is optically reproduced by scanning the recording track of the read-only region A 10  and the recording/reproducing region A 20  with a light beam by the optical pickup  13 . The disc recording and/or reproducing apparatus includes an A/D converter  2  for converting the input analog audio signals into digital signals, a D/A converter  21  for performing a conversion which is the reverse of that performed by the A/D converter  2 , and a level detecting circuit  3  for detecting the signal level indicated by the audio data digitized by the A/D converter  2  from the analog signal. The disc recording and/or reproducing apparatus includes a system controller  4  for controlling the operation of the system in its entirety, and a compression/expansion circuit  6  for performing compression and expansion of the output digital signal of the A/D converter  2 . The disc recording and/or reproducing apparatus also includes a memory controller  7  for temporarily storing output audio data of the compression/expansion circuit  6  in a buffer memory  18 , and an encoder/decoder  8  for performing signal conversion in meeting with the disc format. The disc recording and/or reproducing apparatus also includes a magnetic head driving circuit  9  for driving the magnetic head  10  and a feed motor  14  for moving the magnetic head  10  and the optical pickup  13  in the radial direction of the disc  11   b . Finally, the disc recording and/or reproducing apparatus includes a servo control circuit  15  for controlling the spindle motor  12 , the optical pickup  13  and the feed motor  14 , and an RF circuit  16  for processing an output signal of the optical pickup  13  and routing the processed signal to the encoder/decoder  8 , the servo control circuit  15  and to an address decoder  17 . 
     When recording data in the recording/reproducing region A 20  of the disc  11   b , the optical pickup  13  radiates a light beam on a target track of the recording/reproducing region A 20  on which a vertical magnetic field modulated in accordance with recording data is applied by the magnetic head  10  being driven by the head driving circuit  9 . As a result, data recording is made photomagnetically in the recording/reproducing region A 20 . The optical pickup  13  radiates a light beam on the target track and detects the reflected light beam. The optical pickup  13  detects the focusing error by a so-called astigmatic method based on the reflected light beam, while detecting the tracking error by the three-beams method according to the output level of the detected reflected light beam. When reproducing data recorded on the read-only region A 10  of the disc  11   b , the optical pickup  13  detects changes in the light intensity of the reflected light beam of the radiated light beam from the target track by a photodetector, not shown, for outputting the playback signals. Also, when reproducing data from the recording/reproducing region A 20  of the disc  11   b , the optical pickup  13  detects the difference in the angle of polarized light (Kerr rotation angle) of the reflected light beam of the radiated light beam from the target track for outputting reproduced signals. 
     An output signal of the photodetector, not shown, of the optical pickup  13  is routed to the RF circuit  16 . The RF circuit  16  generates focusing error signals and tracking error signals for an output signal of the optical pickup  13  and transmits these error. signals to the servo control circuit  13 . The RF circuit  16  also extracts address data from an output signal of the optical pickup  13  and transmits the address data to the address decoder  17  and the encoder/decoder  8 . The servo control circuit  15  is composed of, for example, a focusing servo control circuit, a tracking servo control circuit, a spindle servo control circuit and a thread servo control circuit. The focusing servo control circuit controls an objective lens of the optical pickup  13  so that the focusing error signal supplied from the RF circuit  16  will be reduced to zero. The tracking servo control circuit controls an optical system or the objective lens of the optical pickup  13  so that the tracking error signal supplied from the RF circuit  16  will be reduced to zero. The spindle servo control circuit controls the spindle motor  12  for rotationally driving the magneto-optical disc  2  at a CLV. The thread servo control circuit controls the feed motor  14  for moving the optical pickup  13  and the magnetic head  10  to the target track position of the disc  11   b  as designated by the system controller  4 . The servo control circuit  15 , taking charge of these control operations, transmits the information showing the operating states of various component parts controlled by the servo control circuit  15  to the system controller  4 . 
     The system controller  4  controls the operations responsive to operating inputs by various keys of an input unit  19 , such as power source key, ejection key, play key, pause key, stop key or recording key. Also the system controller  4  controls, based on the sector-based address information reproduced from the recording tracks of the disc  11   b , the recording position. or the playback position on the recording track scanned by the optical pickup  13  and the magnetic head  10 . The system controller  4  has enclosed therein a RAM for storage of TOC data read out from the lead-in region A 12  of the read-only region A 10  of the disc  11   b . Based on the TOC data, the system controller  74  controls the playback position of the program region All of the read-only region A 10 . The memory controller  7  stores the U-TOC data read out from the U-TOC region A 22  of the recording/reproducing region A 20  of the disc  11   b  in the RAM. The memory controller  7  controls, based on the registered U-TOC data, the recording position or the playback position on the program region A 21 . 
     The memory controller  7  also controls display on a display unit  20  of the time information, such as total play time of the disc  11   b , the time elapsed since start of play of a music data or an audio data, the remaining play time of the song or program being played and the total remaining play time, or the track number of the music data or the audio data or program. The memory controller  7  also causes the disc name or the track names, if any, of the disc to be displayed on the display unit  20 . If the recording time and data of the program or. the disc is recorded, the recording time and data are also displayed on the display unit  20 . 
     With the disc recording and/or reproducing apparatus of the present embodiment, the analog audio signal supplied to the input terminal  1   a  during the recording mode is converted by the A/D converter  2  into a digital signal with the sampling frequency of 44.1 Khz and the quantizing bits equal to 16. The digital audio signal outputted from the A/D converter  2  is routed to the level detection unit  3  and the compression/expansion circuit  6 . The compression/expansion circuit  6  performs modified DCT (Discreate Cosine Transform) for converting audio data on the time axis into audio data on the frequency axis, while also performing data compression. 
     The compressed output audio data from the compression/expansion circuit  6  is once stored via the memory controller  7  in the buffer memory  18  having a data capacity of not less than one cluster, such as a storage capacity of 1 Mbits, and is read out from the buffer memory and routed to the encoder/decoder  8 . 
     The encoder/decoder  8  performs error correction operations on the audio data read out from the buffer memory  18 , using cross interleave Reed Solomon code (CIRC) as the error correction code, and generates recording data by eight-to-fourteen (EFM) modulation. 
     The recording data thus generated is routed via the head driving circuit  9  to the magnetic head  10 . Thus the vertical magnetic field modulated by the recording data is applied to the disc  11   b . The optical pickup  13  radiates a light beam having a recordable output level on the disc  11   b . This records the recording data photomagnetically on the disc  11   b.    
     Data recording is carried out on the cluster basis. Each cluster is made up of 36 sectors, with each sector corresponding to one subcode block of a CD and made up of 5.5 sound groups. That is, 32 sectors of 36 sectors are allocated to data recording, with the remaining four sectors being used as a linking area for initiation of the vertical magnetic field at the time of starting of recording or for timing matching for controlling the output level of the light beam. 
     The position on the disc during recording is designated by addresses recorded by wobbling the groove provided on the disc  11   b . The address is extracted by the address decoder  17  so as to be routed to the encoder/decoder  8 . 
     During the playback mode, the signal recorded on the disc  11   b  is read out by the optical pickup  13 . An output signal from the optical pickup  13  is routed from the RF circuit  16  as a playback signal to the encoder/decoder  8 . The encoder/decoder  8  EFM demodulates the playback signals supplied thereto and performs error correction operations on the playback signals. 
     The playback data, corrected for errors by the encoder/decoder  8 , are once stored in the buffer memory  18  via the memory controller  7 . The playback data read out from the buffer memory  18  is routed to the compression/expansion circuit  6 . The compression/expansion circuit  6  performs expansion corresponding to compression at the time of recording on the playback data supplied thereto for converting the playback data into audio data on the time axis. The D/A converter  21  converts the audio signals supplied from the compression/expansion circuit  6  into analog audio signal. The analog audio signal outputted from the D/A converter  21  is outputted at an output terminal  22 . 
     The buffer memory  18  has a storage capacity of storing the playback data continuing for approximately 0.9 second, which corresponds to the analog audio signal continuing for about three seconds. Thus, if the signal recorded on the disc  11   b  becomes unable to be read out by the optical pickup  13  due to track jump, with the playback data having been stored in the buffer memory to its full storage capacity, the playback signal may be continuously outputted for about three seconds. The optical pickup  13  is restored during this three-second period to the original position prior to track jump and re-accessing and signal re-reading is attempted again in order to prevent an interrupted output signal at the output terminal  22 . 
     When the disc recording and/or reproducing apparatus of the present embodiment performs the above-described recording operation, the system controller  4  performs system control, on the basis of a detection output by the level detector  3 , as indicated by the flow chart shown in FIG.  6 . 
     That is, when the recording mode is set, the system controller  4  controls various parts of the apparatus at a step SP 1  for starting the recording of the program on the disc  1   b . Processing then transfers to a second step SP 2 . 
     At the step SP 2 , it is checked, on the basis of the detection signal by the level detector  3 , whether or not the signal level of the audio signal to be recorded, that is the audio level, has reached the pre-set level, for example, −80 dB. At the second step SP 2 , the above check operation is repeatedly performed until the result of decision is YES, that is until the audio level exceeds −80 dB. That is, the apparatus awaits the delivery of the audio level exceeding −80 dB in the recording state. When the result of decision at the second step SP 2  becomes YES, processing transfers to the next step SP 3  where the timer is reset. Processing then transfers to the next step SP 4 . 
     The timer is enclosed in the system controller  4  and is used for measuring the time interval during which the audio level is below a pre-set level. An address counter for counting the addresses detected by the address decoder  17  may be employed as the timer. 
     At the fourth step SP 4 , it is checked, on the basis of the detection signal by the level detector  3 , whether or not the audio level has become lower than a pre-set level, for example, −80 dB. If, at the fourth step SP 4 , the result of decision is NO, that is if the audio level exceeds −80 dB, processing reverts to the second step SP 2  in order to perform the operations from the step SP 2  up to the step SP 4  repeatedly. In this manner, the recording state is continued for the audio signals having the audio level in excess of a pre-set level, while the timer is reset. If, at the fourth step SP 4 , the result of decision becomes YES, that is the audio level becomes less than −80 dB, processing transfers to the next step SP 5 . 
     At the fifth step SP 5 , it is checked whether or not a pre-set time interval, for example, 20 seconds, has elapsed since the timer is reset at the step SP 3 . At the fifth step SP 5 , if the result of decision is NO, that is if the pre-set time interval has not elapsed since the timer is last reset, processing transfers to the fourth step SP 4  in order to perform the decision on the audio level iteratively. If the audio level is raised by more than −80 dB before a pre-set time elapses since the timer is last reset, processing reverts from the fourth step SP 4  to the second step SP 2  in order to continue the recording operation as the timer is reset. If, at the fifth step SP 5 , the result of decision is YES, that is if the state of the audio level being less than −80 dB continues for a pre-set time interval since the timer is reset, processing transfers to the next sixth step SP 6 . 
     At the sixth step SP 6 , the control operation of discontinuing the recording operation is performed. Processing then transfers to the next seventh step SP 7 . Thus the recording operation is automatically discontinued if the state of the audio level being less than −80 dB continues for a pre-set time interval. 
     At the next seventh step SP 7 , the U-TOC data is re-written on the RAM enclosed in the system controller  4  so that data continuing for a pre-set time interval at the end part of the recorded audio data, for example, data continuing for 18 seconds, is separated as being audio data of another song or program. This automatically separates the silent invalid recorded portion, produced at the end part of the recorded audio data, from the valid recorded data. 
     At the next eighth step SP 8 , the U-TOC data on the RAM is rewritten for deleting the last program data portion separated at the seventh step SP 7 , that is the program data portion composed of data continuing for the above-mentioned pre-set time interval. The U-TOC data is then read out from the RAM of the system controller  4  so as to be recorded in the U-TOC region A 22  of the recording/reproducing region A 20  of the disc  11   b . This automatically deletes the silent invalid recorded portion produced towards the end part of the recorded audio data. 
     By such recording control, it is possible with the disc recording and/or reproducing apparatus of the present embodiment to discontinue recording automatically if, during the recording, the state of the audio level being less than −80 dB is continued for 20 seconds, in order to delete the silent audio data during the time interval beginning from a time point preceding a pre-set time from the terminal point of recording and ending at the terminal point of recording, that is, for the last 18 seconds. 
     With the disc recording and/or reproducing apparatus of the present embodiment, the program data portion consisting of data continuing for the above-mentioned pre-set time interval is automatically deleted as being the invalid recorded portion. However, the program data portion composed of data continuing for the pre-set time interval may also be. deleted by a manual operation at the key input section. 
     Also, when recording data by the disc recording and/or reproducing apparatus, the recording control may also be performed on the basis of the detection signal by the level detector  3  in accordance with the flow chart shown in FIG. 7, instead of performing the above-mentioned recording control in accordance with the flow chart shown in FIG.  6 . 
     In the recording control shown in the flow chart of FIG. 7, the system controller  4  causes the recording to be started at a step SP 10 , when the recording mode is set, and causes the memory to be cleared at a second step SP 11 , before proceeding to the third step SP 12 . 
     The memory is used for storing the addresses indicating the audio data recording position, and is enclosed within the system controller  4 . 
     At the third step SP 12 , the system controller  4  checks, based upon the detection signal by the level detector  3 , whether or not the signal level of the audio signal to be recorded, that is the audio level, has reached −80 dB. If the result at the third step SP 12  is YES, that is if the audio level is more than −80 dB, the system controller proceeds to a fourth step SP 13  to clear the memory. The system processor then proceeds to the next fifth step SP 14 . If, at the third step SP 12 , the result of decision is NO, that is if the audio level is less than −80 dB, the system controller proceeds to a seventh step SP 16 . 
     At the fifth step SP 14 , it is checked, based on the detection signal by the level detector  3 , whether or not the audio level becomes lower than a pre-set level, for example, −80 dB. If the result of decision at the fifth step SP 14  is NO, that is if the audio level is higher than −80 dB, the system controller proceeds to the seventh step SP 16 . If the result of decision at the fifth step SP 14  is YES, that is if the audio level is less than −80 dB, the system controller proceeds to a sixth step SP 15  to store an address indicating the audio data recording position in the memory. The system controller  4  then reverts to the third step SP 12  for iterating the operation of decision of the audio level. Thus, each time the audio level exceeds −80 dB, the memory is cleared, and an address indicating the leading recording position of the audio data having the audio level less than −80 dB is stored in the memory. 
     At the seventh step SP 16 , it is checked whether or not the recording has been discontinued. If, at the seventh step SP 16 , the result of decision is NO, that is if the apparatus is in the recording state, the system controller  4  reverts to the third step SP 12  for iterating the operation of audio level decision. The system controller then proceeds to the next eighth step SP 17 . 
     If the system controller  4  accepts a stop command input from the input operating unit  19 , or if the program region A 21  of the recording/reproducing region A 20  of the disc  11   b  becomes depleted of the recordable region, the system controller causes the recording operation to be discontinued. 
     At the eighth step SP 17 , the system controller decides whether or not an address indicating the leading storage position of the audio data having the audio level less than −80 dB is stored in the memory. If, at the eighth step SP 17 , the result of decision is YES, that is if such address is stored in the memory, the system controller proceeds to the next ninth step. If the result of decision is NO, that is if such address is not stored in the memory, the system,controller  4  proceeds to the eleventh step SP 20 . 
     At the ninth step SP 18 , the U-TOC data is re-written on the RAM enclosed within the system controller  4  so that the recorded audio data bearing the addresses subsequent to the address stored in the memory will be separated as being audio data of another program or song. This automatically separates the effective recorded portion from the silent invalid recorded portion produced towards the end of the recorded audio data. 
     At the next tenth step SP 19 , the U-TOC data is re-written on the RAM for deleting the last program portion, as separated at the ninth step SP 18 , which is the invalid recorded portion. 
     At the next eleventh step SP 20 , the U-TOC data is read out from the RAM and recorded in the U-TOC region A 22  of the recording/reproducing region A 20  of the disc  11   b . In this manner, if there is any silent invalid recorded portion towards the end of the recorded audio data, this invalid portion is deleted automatically. 
     The invalid portion may also be deleted at the tenth step SP 19  by the manual operation of the input unit  19 . 
     Although the above description has been made of the disc recording and/or reproducing apparatus employing a disc-shaped recording medium, such as an optical disc, the present invention may also be applied to a tape recording and/or reproducing apparatus employing a tape-shaped recording medium.