JP2002304874A - Method for calculating recordable time - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recordable time calculating method that can accurately calculate a remaining recordable time of an optical disk and display the calculated recordable time in a disk recording and reproducing device that records/ reproduces an audio signal to/from the optical disk. SOLUTION: A UTOC(User Table Of Contents) of a magneto-optical disk 2 records in advance an address indicating a position of data and an address indicating a position of non-recorded area. A TOC(Table Of Contents) memory 20 reads the address denoting the position of the non-recorded area of the UTOC and by using the address denoting the position of the non-recorded area, the number of clusters of the remaining recordable area is obtained. The number of clusters is used to convert the remaining recordable time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of calculating a recordable time suitable for displaying a remaining recordable time of a disk recording / reproducing apparatus for recording / reproducing an optical disk or a magneto-optical disk.

[0002]

2. Description of the Related Art Diameter 64 mm stored in a cartridge
An optical disk recording / reproducing system (mini-disc (MD) system) for recording and reproducing digital audio signals using an optical disk or a magneto-optical disk has been developed (for example, Japanese Patent Application No. 3-275067). In such an optical disk recording / reproducing system, a digital audio signal is compressed to about 1/5 using an audio compression technique and recorded. As a result, recording of a high-quality audio signal for about 74 minutes on a small-diameter disk having a diameter of 64 mm /
Reproduction is possible.

In such an optical disk recording / reproducing system, audio data is compressed and recorded in units of clusters composed of 36 sectors. Of the 36-sector cluster, 32 sectors are used for data.
The remaining four sectors are used for sub data.

At the time of reproduction, reproduction data from the optical disk is temporarily stored in a buffer memory (DRAM). If the digital signal on the disk cannot be read due to vibration or the like, the reproduction signal is continuously output for about 3 seconds by the data stored in the buffer memory.
In the meantime, by re-accessing the optical pickup to the original position and reading the signal again, it is possible to prevent the occurrence of so-called skipping. This buffer memory is called a shock proof memory.

[0005]

In such an optical disk recording / reproducing system, it is conceivable to display the remaining recordable time. For a magnetic tape or the like, the current recording position is detected, and if the time corresponding to the current recording position is present from the total recording time, the remaining recording time can be obtained. However, in such an optical disk recording / reproducing system, audio data is recorded in a compressed state, and an arbitrary position on the disk can be accessed for recording / reproduction. possible. In the optical disc, data is recorded in units of clusters composed of 36 sectors.
Data cannot be recorded in a free area of one cluster or less.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a recording time calculation method for accurately calculating and displaying the recordable time of a disk.

[0007]

According to the present invention, there is provided a recordable time calculation method for calculating a remaining recordable time on a disk, wherein an address indicating a data position and an unrecorded area are recorded in a list of the disk. The address indicating the position is recorded in advance, the inventory data is reproduced, the remaining recordable time immediately before recording is calculated using the address indicating the position of the non-recording area obtained from the inventory data, and To
From the number of clusters recorded from the start of recording to the present, the recording time from the start of recording to the present is calculated, and the remaining recording time from the start to the present is subtracted from the remaining recordable time immediately before recording. Is obtained and is output as the remaining recordable time during recording.

According to the present invention, in a recording time calculation method for calculating a remaining recording time recordable on a disk, an index indicating a data position and an address indicating a position of a non-recording area are included in a list of the disk. The data of the inventory recorded in advance is reproduced, the number of clusters of the remaining non-recording area immediately before recording is calculated using the address indicating the position of the non-recording area obtained from the data of the inventory, and recording is started during recording. Count the number of clusters recorded from time to the present, subtract the number of clusters recorded from the start of recording to the present from the number of clusters in the remaining non-recording area immediately before recording, and Recordable time that converts the subtraction value between the number of clusters and the number of clusters recorded from the start of recording to the present to the recording time and outputs it as the remaining recordable time during recording It is a calculation method.

[0009] The UTOC is reproduced, the number of remaining recordable clusters is obtained by using the address indicating the position of the non-recording area obtained from the UTOC, and the remaining recordable time is obtained by converting this number of clusters into time. Desired.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an optical disk recording / reproducing system (mini-disc (MD) system) for recording and reproducing digital audio signals using an optical disk or a magneto-optical disk having a diameter of 64 mm stored in a cartridge. Used to display the remaining recordable time. As shown in FIG. 2, the magneto-optical disc 2 to which the present invention is applied, a reproduction-only area A _10, the recording and reproducing area A ₂₀ that is provided outside the read-only area A ₁₀
And Reproduction-only area A ₁₀ includes a data area A ₁₁ in which data such as performance information is recorded, and a lead-in area A ₁₂ provided on the inner periphery thereof. Lead-in area A
₁₂ is TOC (Table Of Contentes).

The recording / reproducing area A ₂₀ of the magneto-optical disk 2 is
Has a data area A ₂₁ in which data such as performance information is recorded, and a lead-in area A ₂₂ provided on the inner periphery thereof. This lead-in area A ₂₂ is UTOC,
Track number information indicating the recording position and recording content of the recording data, address information indicating the position of the area of each data, and connection address information to other data areas are recorded.

FIG. 3 shows the configuration of the UTOC. In the data table of FIG. 3, the vertical address "0-3" in byte units is header data, the 12 bytes of the vertical address "0-2" are the synchronization signal, and the first byte of the vertical address "3". And the second byte are assigned to the cluster address. Also, the vertical address “1”
P-DFA, PE of the second and third bytes of "1"
MPTY, P-FRA of vertical address "12", P-
TNOn is a pointer indicating the block definition data of the 76th and subsequent addresses in the vertical direction. P-DFA is a pointer indicating the start address of the defective area. PE
MPTY is a pointer indicating the start of an unused portion of the block definition data block. PF
RA is a pointer to the start address of a freely recordable area. P-TNOn is a pointer indicating the start address of the track number n. The value of the pointer P-TNOn gives the start address of the track number TNO-n given by start address = 76 × 4 (P-TNOn) × 8.

The vertical address "76-85"
Forms an address table of the data area, and is assigned to a start address and an end address of the data area specified by the pointers P-FRA and P-TNOn. Further, the fourth byte of the even address after the vertical address "76" is allocated to various track modes such as a copyright protection mode and a rewrite inhibition mode. Then, the fourth address of the odd address after the vertical address “76”
Bytes are allocated to a pointer Link-P indicating a connection destination from one data area to another data area.

On the basis of the UTOC data, the remaining recordable time of the disc is obtained. That is, as described above, the start address of the recordable area is the pointer P
-Obtain block definition data pointed to by FRA.

As for the start and end addresses, as shown in FIG. 4, 14 bits from the beginning indicate a cluster, the next 6 bits indicate a sector, and the next 4 bits indicate a sound group (compression work). The smallest unit performed).

The number of clusters in the recordable area is obtained from the cluster address part (upper 14 bits) of the start address and the end address cluster address part of the block definition data indicated by the pointer P-FRA. If a recordable area continues, a link destination of the subsequent recordable area is indicated by Link-P. From the cluster address portion of the start address and the cluster address portion of the end address of the block definition data indicated by the Link-P, the number of clusters in the recordable area following the start address can be obtained. The remaining recordable time can be obtained by multiplying the number of remaining clusters of the disk thus obtained by the performance time per cluster.

In the case of stereo, the sampling frequency is 4
At 4.1 KHz, the number of samples per sound group is 512. The number of sound groups per sector is 5.5, and the number of sectors per cluster is 32. Therefore, the performance time per cluster is (1 / 44.1 kHz) × 512 × 5.5 × 32 = 2.
04 seconds.

As shown in FIG. 5A, the start and end of the remaining recordable area do not coincide with the start and end of the cluster, and the start and end of the remaining recordable area and the cluster as shown in FIG. 5B. If the beginning matches, the end of the remaining recordable area coincides with the end of the cluster as shown in FIG. 5C, or the beginning of the remaining recordable area and the beginning of the cluster as shown in FIG. 5D The number of clusters that can be recorded differs between the case where they match and the end of the remaining recordable area coincides with the end of the cluster.

That is, in the case of FIG. 5A, FIGS.
Also in the case of D, the number of clusters obtained by subtracting the cluster address part of the start address and the cluster address part of the end address is “4”, which are all the same. However, in the case of FIG. 5A, data cannot be recorded in the first cluster C1 since the remaining cluster C1 at the head does not match the head TC of the cluster. Also, since the end of the last cluster C5 does not match the end EC of the cluster, data cannot be recorded in the last cluster C5. Therefore, the number of clusters on which data can be recorded is C2 to C
Four “3” clusters are obtained.

On the other hand, as shown in FIG. 5B, if the leading cluster C1 and the leading TC of the cluster match,
Since data can be recorded in the first cluster C1, the number of clusters in which data can be recorded is "4" clusters C1 to C4. Also, as shown in FIG. 5C, the first cluster C
If 5 matches the last EC of the cluster, data can also be recorded in the last cluster C5, and the number of clusters in which data can be recorded is “4” clusters C2 to C5. Further, as shown in FIG. 5D, the first cluster C1
Matches the first TC of the cluster and the last cluster C
If 5 matches the last EC of the cluster, the number of clusters in which data can be recorded is “5” clusters C1 to C5.

Therefore, if the first cluster C1, the first TC of the cluster and the end of the last cluster C5 and the end EC of the cluster do not match, the number of recordable clusters is the cluster address part of the start address and the cluster of the end address. This is the number of clusters obtained by subtracting “1” from the value obtained by subtracting the address part. If the first cluster C1 matches the first TC of the cluster or the last cluster C5
Is equal to the end EC of the cluster, the number of recordable clusters is the number of clusters obtained by adding "1" to the number.

FIG. 6 is a flowchart showing a process for calculating the remaining recordable time of the disc from the UTOC data. In FIG. 6, UTOC data is read (step 51). And the pointer PF
The RA is read (step 52), and the pointer P-FR is read.
The start address and end address of the block definition data indicated by A are read (step 53). Pointer P
-The block definition data indicated by the FRA is ((P-F
(RA value × 8) + (76 × 4)).

The number of free clusters is initialized to "0" (step 54). Then, it is determined whether or not the start address matches the head of the cluster (step 5).
5). If the start address matches the beginning of the cluster, "1" is added to the number of free clusters (step 56), and then it is determined whether the end address matches the end of the cluster (step 56). 57). If the start address does not match the beginning of the cluster in step 55, then in step 57 it is determined whether the end address matches the end of the cluster.

If it is determined in step 57 that the end address matches the end of the cluster, "1" is added to the number of free clusters (step 58). Then, the cluster address part of the start address and the cluster address part of the end address are subtracted, and 1 is subtracted therefrom (step 59). If it is determined in step 57 that the end address does not match the end of the cluster, then in step 59
Then, the cluster address part of the start address and the cluster address part of the end address are subtracted, and 1 is subtracted from it.

The link definition of the block definition data
P is read (step 60). If Link-P is "0", the number of free clusters is multiplied by the reproduction time per cluster (2.04 seconds for stereo) to obtain the remaining recording time (step 62). Step 60
If Link-P is not "0", the start address and the end address of the block definition data pointed to by Link-P are read (step 63), and the process returns to step 55 to start the block indicated by this Link-P. The number of clusters is obtained from the address and the end address in the same manner as described above, and the remaining recording time is obtained from the number of clusters.

By the way, in such an optical disk recording and reproducing system, a track jump at the time of writing causes
It is recommended that a card band be provided so that previously recorded data of adjacent clusters is not affected. That is, as shown in FIG. 7, one cluster between the previously recorded area and the start of the unrecorded area to be recorded this time, and one cluster between the previously recorded area and the unrecorded area to be recorded this time are guard band GB. It is said. By providing such a guard band GB, it is possible to prevent the pickup from being moved to an adjacent recorded area due to a shock of a track jump at the time of recording and the data in the recorded area is erased. The size of the guard band GB can be set for each device according to the movement accuracy of the pickup at the time of a track jump.

When the guard band GB is provided as described above, the number of clusters corresponding to the guard band GB is subtracted from the number of clusters obtained from the start address and the end address when obtaining the remaining recordable time. At this time, a value obtained by subtracting the number of clusters corresponding to the guard band from the number of clusters obtained from the start address and the end address may be negative. In this case, the number of recordable clusters is treated as “0”.

FIG. 8 shows the processing in the case where the guard band is provided as described above. In FIG.
UTOC data is read (step 71). Then, the pointer P-FRA is read (step 7).
2) The start address and end address of the block definition data indicated by the pointer P-FRA are read (step 73).

The number of free clusters is initialized to "0" (step 74). Then, it is determined whether or not the start address matches the head of the cluster (step 7).
5). If the start address matches the beginning of the cluster, "1" is added to the number of free clusters (step 76), and then it is determined whether the end address matches the end of the cluster (step 76). Step 77).
If the start address does not match the start of the cluster in step 75, then it is determined in step 77 whether the end address matches the end of the cluster.

If the end address matches the end of the cluster at step 77, "1" is added to the number of free clusters (step 78). Then, the cluster address part of the start address and the cluster address part of the end address are subtracted, and 1 is subtracted therefrom (step 59). If the end address does not match the end of the cluster in step 77, then step 79
, The upper 14 bits of the start address and the end address are subtracted, and 1 is subtracted therefrom.

Further, the number of clusters corresponding to the guard band (for example, two clusters) is reduced (step 80).
Then, it is determined whether or not the number of clusters obtained by subtracting the number of clusters corresponding to the guard band is 1 or more (step 8).
1). In step 81, if the number of clusters obtained by subtracting the number of clusters corresponding to the guard band is 1 or more, Link-P of the block definition data is read (step 83).
If the number of clusters obtained by subtracting the number of clusters corresponding to the guard band in step 81 is not one or more, the number of empty classes is set to "0" (step 82), and Link-P of the block definition data is read (step 82). 8
3).

If Link-P is "0", the number of free clusters is equal to the reproduction time per cluster (2.0 for stereo).
4 seconds) to obtain the remaining recording time (step 86). In step 84, if Link-P is not "0", the start address and end address of the block definition data pointed to by Link-P are read (step 85), and the process returns to step 75, where the block indicated by Link-P is read. From the start address and end address of
As described above, the number of clusters is obtained, and the remaining recording time is obtained from the number of clusters.

FIG. 1 shows an example of an optical disk recording / reproducing apparatus to which the present invention can be applied. In FIG. 1, a magneto-optical disk 2 is rotated by a spindle motor 1. At the time of recording, for example, a laser beam is irradiated by the optical head 3 and a modulation magnetic field corresponding to the recording data is applied to the magnetic head 4.
Is applied to During reproduction, a laser beam is emitted from the optical head 3 along the recording track of the magneto-optical disk 2. Thus, data is optically reproduced from the output of the optical head 3.

The output of the optical head 3 is supplied to an RF circuit 5. The output of the RF circuit 5 is supplied to the servo control circuit 6 and also to the decoder 21. The servo control circuit 6 includes a focus control circuit, a tracking control circuit, and a thread servo circuit. The focus control circuit controls the focus of the optical system of the optical head 3 so that the focus error signal becomes “0”. Further, the tracking servo circuit performs tracking control of the optical system of the head 3 so that the tracking error signal becomes “0”. Further, the spindle motor servo control circuit controls the spindle motor 1 so as to rotate the magneto-optical disk 2 at a predetermined rotation speed. Further, the optical head 3 and the magnetic head 4 are moved to target track positions of the magneto-optical disk 2. The servo control circuit 6 that performs such various control operations supplies information indicating the operation state of each unit controlled by the servo control circuit 6 to the system controller 7.

The system controller 7 is connected to a key input operation unit 8 and a display unit 9. An input from the key input operation unit 8 is given to the system controller 7, whereby an operation mode is set. System controller 7
The optical head 3 and the magnetic head 4 are based on address information reproduced from a recording track of the magneto-optical disk 2.
Manages the recording position and the reproduction position on the recording track being traced.

At the time of recording, an analog audio signal is supplied from the input terminal 10 via the low-pass filter 11. This analog audio signal is supplied to the A / D converter 12. The A / D converter 12 converts the analog audio signal into 2 channels × 16 bits × 44.1 kHz ≒ 1.4.
Digitization is performed at a data rate of Mbit / s. The output of the A / D converter 12 is supplied to a compressor 13.

The compressor 13 performs a process of compressing the digital audio signal from the A / D converter 12 by a high-efficiency encoding process. As a result, audio data at a data rate of 1.4 Mbit / s is about 1/5 of 300
It is compressed to a data rate of kbit / s. As a result, the data transfer rate is converted from 75 sectors / second to about 15 sectors / second.

The compressed audio signal is stored in the RAM 1
4 is supplied. The RAM 14 temporarily stores the compressed audio signal supplied from the compressor 13 and is used as a buffer memory for recording the compressed audio signal on a disk as needed. That is, the compressed audio data supplied from the compressor 13 has a transfer rate of about 1 / standard of the standard.
5, which is reduced to about 15 sectors / second, and the compressed data is continuously written to the memory 14. For this compressed data, it is sufficient to record one sector for every five sectors.
Since such recording at every five sectors is extremely difficult in real time, data transfer of 75 sectors / second is performed in units of a cluster consisting of a predetermined plurality of sectors (for example, 32 sectors + several sectors) through a pause. It is done in bursts at speed. That is, in the memory 14, compressed audio data written continuously at a low transfer rate of 15 (= 75/5) sector seconds according to the bit compression rate is read out in a burst at a transfer rate of 75 sectors / second. It is.

The compressed audio data read from the memory 14 in a burst manner is supplied to an encoder 15. Here, in the data string supplied from the memory 14 to the encoder 15, a unit continuously recorded in one recording is a cluster including a plurality of sectors. As shown in FIG. 9, one cluster consists of 36 sectors, which is 32 sectors.
It consists of main data of a sector and sub data of four sectors. One sector is composed of 2352 bytes. By performing such recording in cluster units, it is not necessary to consider mutual interference by interleaving between other clusters. If the recording data cannot be recorded at the time of recording due to out-of-focus, tracking deviation, or other malfunction, re-reading can be performed in cluster units.

The encoder 15 performs encoding processing for error correction (parity addition and interleaving processing) on the recording data supplied from the RAM 14 in a burst manner, and performs EFM modulation on the encoding processing. This encoder 1
5 is supplied to the magnetic head drive circuit 16. The magnetic head drive circuit 16 is connected to the magnetic head 4 and generates a modulation magnetic field corresponding to the recording data.
Is driven to drive the magnetic head 4.

Next, the reproduction time will be described. At the time of reproduction, the recorded data on the magneto-optical disk 2 is reproduced by the optical head 3, and the reproduced signal is supplied to the RF circuit 5.
The output of the RF circuit 5 is supplied to the decoder 21. The decoder 21 corresponds to the encoder 15 in the recording system, and performs EFM demodulation on the reproduced signal, and performs error correction encoding on the demodulated signal. The output of the decoder 21 is supplied to the RAM 22. Data from the decoder 21 is burst-written into the RAM 22 at a transfer rate of 75 sectors / sec. The data written in the memory 22 is continuously read at a transfer rate of 15 sectors / second.

The system controller 7 converts the TOC data and UTOC data read from the magneto-optical disk 2 into T
The data is stored in the OC memory 20 and the recording position and the reproduction position are managed based on the TOC data.

The output of the memory 22 is supplied to a decompressor 23. The expander 23 corresponds to the compressor 13 of the recording system, and expands the compressed audio data by about 5 times.
Digital audio data with a transfer rate of 75 sectors / second is reproduced. The output of the expander 23 is supplied to a D / A converter 24 and to a digital output circuit 27. The output of the digital output circuit 27 is output from the output terminal 26.

The D / A converter 24 converts a digital audio signal into an analog audio signal. This analog audio signal is output from the output terminal 26 via the low-pass filter 25.

In the optical disk recording / reproducing apparatus to which the present invention is applied, during recording, the recordable time of the disk is displayed on the display unit 9 as shown in FIG. FIG. 10 shows a display before the start of recording. Before the start of recording, the display unit 9 displays
Track number display 41 and remaining recordable time display 4
2 is performed. 11A and 11B show the display during recording. During recording, the display section 9 displays a track number display 41, a remaining recordable time display 42,
This time recording time display 43 is done. As the current recording time advances, as shown in FIG. 11B, the current recording time display 43 advances, and the remaining recordable time 42 decreases accordingly.

The recordable time of this disc is obtained from the UTOC disc management information as described above.
Then, the recordable time is displayed as follows.

As shown in FIG. 12, before recording, it is determined whether or not the disk 2 is inserted (step 1).
01), if the disk 2 is inserted, the disk management information of the UTOC is read into the TOC memory 20 (step 102). As described above, the remaining disc recordable time is obtained from the disc management information (step 103). Then, the remaining recordable time of the disc is displayed on the display unit 9 (step 104).

As shown in FIG. 13, during recording, while recording audio data on the disk 2 (step 111), the recording time is counted (step 1).
12). Based on the recording time, the disc recordable time is recalculated (step 113). Then, the remaining recordable time of the disc is displayed on the display unit 9 (step 114), and it is determined whether or not the recording is completed (step 115). If the recording is not completed, the process returns to step 111 to record the audio data. Is continued, step 11
The recording time is counted at 2, the remaining recordable time is recalculated at step 113, and the remaining recordable time is displayed at step 114.

In the above-described example, the remaining recordable time during recording is determined by obtaining the time of recording up to the present time and subtracting the time of recording up to the present time from the recordable time of the disc immediately before recording. The number of clusters of audio data recorded so far is calculated, the number of clusters of audio data recorded so far is subtracted from the number of clusters that can be recorded on the disc immediately before recording, and this number of clusters is converted to time. May be displayed.

In one embodiment of the present invention, the display 9
The remaining recordable time is displayed as a numerical value, but the remaining recordable time may be displayed as a bar graph or the like as shown in FIG. When the remaining recordable time becomes equal to or shorter than the predetermined time, the indicator lamp may be turned on or a buzzer may sound a warning sound.

[0051]

According to the present invention, UTOC is reproduced,
The number of remaining recordable clusters is obtained using the address indicating the position of the non-recording area obtained from the UTOC, and the remaining recordable time is obtained by converting the number of clusters into time. Therefore, the remaining recordable time can be displayed at the time of recording in the optical disk recording / reproducing system.

[Brief description of the drawings]

FIG. 1 is a block diagram of an example of an optical disk recording / reproducing apparatus to which the present invention can be applied.

FIG. 2 is a plan view used for describing a magneto-optical disk to which the present invention can be applied.

FIG. 3 is a schematic diagram used for describing one embodiment of the present invention.

FIG. 4 is a schematic diagram used for explaining an address in the embodiment of the present invention.

FIG. 5 is a schematic diagram used for describing the present invention.

FIG. 6 is a flowchart used to explain an embodiment of the present invention.

FIG. 7 is a schematic diagram used for describing a guard band in the embodiment of the present invention.

FIG. 8 is a flowchart used to explain another embodiment of the present invention.

FIG. 9 is a schematic diagram used for describing a cluster in the embodiment of the present invention.

FIG. 10 is a plan view used for explaining a display unit of the optical disc recording / reproducing apparatus to which the present invention is applied.

FIG. 11 is a plan view used for explaining a display unit of the optical disc recording / reproducing apparatus to which the present invention is applied.

FIG. 12 is a flowchart used to describe the display of a recordable time in a disk recording / reproducing apparatus using light to which the present invention is applied.

FIG. 13 is a flowchart used to describe the display of a recordable time in a disk recording / reproducing apparatus using light to which the present invention is applied.

FIG. 14 is a flowchart used to explain another example of display of a recordable time in a disk recording / reproducing apparatus using light to which the present invention is applied.

[Explanation of symbols]

 2 Magneto-optical disk 7 System controller 9 Display section 20 TOC memory 42 Remaining recordable time display 43 Current recording time display

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D044 AB05 AB07 BC04 CC04 DE38 DE48 EF10 5D077 AA30 HC09

Claims (2)

[Claims] 1. A recording time calculation method for calculating a remaining recording time recordable on a disc, wherein the list of discs includes an address indicating a data position and an address indicating a non-recording area position in advance. The recorded data is reproduced, the inventory data is reproduced, and the remaining recordable time immediately before recording is calculated using the address indicating the position of the non-recording area obtained from the inventory data. From the number of clusters recorded from to the present, the recording time from the start of the recording to the present is calculated, and the remaining recordable time immediately before the recording is subtracted from the recording time from the start to the present to obtain the remaining recordable time. Is calculated and output as the remaining recordable time during recording. 2. A recording time calculation method for calculating a remaining recording time recordable on a disk, wherein an index indicating a data position and an address indicating a non-recording area position are previously stored in a list of the disk. The recorded data is reproduced, the inventory data is reproduced, the number of clusters of the remaining non-recorded area immediately before recording is calculated using an address indicating the position of the non-recorded area obtained from the data of the inventory, and the recording is performed during recording. The number of clusters recorded from the start to the present is counted, and the number of clusters recorded from the start of the recording to the present is subtracted from the number of clusters in the remaining non-recording area immediately before the recording. Convert the subtraction value between the number of clusters in the non-recording area and the number of clusters recorded from the start of recording to the present to the recording time, and output it as the remaining recordable time during recording Recording time calculation method.