JPH05198144A - Disk device and method for reading time information - Google Patents

Abstract

PURPOSE:To enable the rapid an exact detection of the terminal of music by detecting the beginning end of the music next to the desired music, detecting the presence or absence of an audio signal by repetition of backward direction and forward direction reproductions and reading the time cord of the time. CONSTITUTION:The beginning end position t5 of the next music N+1 or the reproduction position t4 of the music N+1 is detected at the time of detecting the terminal position t3 of the music N. A prescribed level L1 and the detected audio signal level are compared in a sound level detecting circuit and whether the actual audio level or the beginning end position of the music is exactly detected at the time of the detection. The terminal position t3 of the music N is then determined from the point of the time there are no more audio signals by the combination of the backward direction reproduction B1, B3, B5 and the forward direction reproductions B2, B4, B6. The time cord of the time is read. Consequently, the terminal of the music is easily and exactly detected and the length and intermusic space of the music N are easily determined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc device such as a CD (compact disc) player and a method for reading time information from a recording medium disc.

[0002]

2. Description of the Related Art Many songs are recorded on a CD with a space between the songs. Further, the song number and time code (time information) are recorded in the subcode area (ID field) of the track format.

By the way, an inter-song space, which hardly causes a problem in general use, becomes a problem in the business such as a broadcasting station. For example, if the vacant time between songs in broadcasting is too long, the maximum vacant time defined by the Radio Law may be exceeded. Therefore, it is necessary to accurately measure the actual length of the song. The actual length of a song can be measured by playing the entire song and the time taken to play it. However, with this method, the time required for measurement becomes too long.

Since the time code is recorded on the CD, the time length of the music can be known by reading the time code at the beginning and end of the music. Conventionally, the head of the designated song is searched for based on the song number, the time code at the time when the audio output is obtained is read on the display device of the CD player, and then the song is played in the high-speed playback (cue) mode. Scan to the end,
The time point at which the sound output is not obtained after normal reproduction from a little before the end is set as the end of the song, and the time code at this time is read from the display device. After that, the time length at the beginning of the song was subtracted from the time code at the end of the song to obtain the actual time length of the song.

Since there is a time difference between the position where the song number is recorded and the position where the song is actually recorded, the voice output is actually performed without using the song number recording position as the start end of the song. It is desirable to set the time point at which is obtained as the beginning of the song. It is possible to detect the silent period to determine the beginning and end of the song, but it is difficult to distinguish it from the silent or low-level section in the song, and it is not possible to determine accurately. now,
Although the CD has been described, there is a similar problem in the magnetic disk device and the like.

Therefore, an object of the present invention is to provide a disk device and method by which the end of an information block such as a music piece can be easily known.

[0007]

In order to achieve the above object, the present invention relates to a rotating device for a recording medium disk in which a plurality of information blocks are recorded with a space between each other and a time code is recorded. A signal converter for reading the information block and the time code from the disc, a feeding device for feeding the signal converter in the radial direction of the disc, and the information block based on the output of the signal converter Signal presence / absence determining means for determining the presence / absence of a signal, end time code reading command means for instructing to read the time code at the end of one information block selected from the plurality of information blocks, and the end time code reading An information block next to the selected information block in response to a terminal time code reading command from the command means. Positioning the signal converter at the start end, the feed device for performing reverse reproduction or combined reproduction in the reverse direction and forward direction from the start position of the next information block toward the end of the selected information block. The present invention relates to a disk device provided with an end detection control unit that controls and determines the end of the selected information block based on the output of the signal presence / absence determination unit and reads the time code at the time of this end determination. Further, the invention of a method for achieving the above object is to arbitrarily select from a plurality of information blocks in a recording medium disc in which a plurality of information blocks are recorded with a space between them and a time code is recorded. A method of reading a time code at the end of one of the selected information blocks, wherein the information block next to the selected information block is output based on the output of the signal converter that reads the information block and the time code from the disc. The step of detecting the start end and the reverse reproduction or the combined reproduction of the reverse reproduction and the normal reproduction from the start of the next information block toward the end of the selected information block are performed, and the output of the signal converter Detecting the end of the selected information block based on, and reading the time code at this time. Those related to the time information reading method in a disk device according to claim Rukoto.

[0008]

According to the inventions of the respective claims, when the end position of the music is determined, the method of reproducing the target music and terminating the end of the music is not adopted, and the next music First, the start point (track number playback position or song start position) is detected, then backward playback is performed, and the presence or absence of an audio signal is detected based on this backward playback or forward playback added to this, and the end position is detected. Read the time code. As a result, it becomes possible to detect the end position of the song quickly and accurately.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a CD player according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a CD player includes a motor 2 as a rotating device for a recording medium disc 1 and an optical pickup 3 as a signal converter.
Have and. On the disc 1, a plurality of songs as a plurality of information blocks are digitally recorded with a space between each other, and a time code (time information signal consisting of continuous absolute time) and a song number are recorded as subcode signals. It is a general CD that is played. The digital signal is recorded on a spiral track shape like a general CD and is recorded at a constant linear velocity. Therefore, the rotation speed of the motor 2 changes according to the change of the scanning position of the light beam 4 projected from the pickup 3 onto the disk 1.

The pickup 3 includes a light source 5, a half mirror 6, a tracking rotation mirror 7, and an objective lens 8.
And a photodetector 10 for detecting the reflected beam 9 and a drive coil 11 for the turning mirror 7. The pickup 3 further includes focus control means,
The illustration is omitted because it is not directly related to the present invention.

The light beam 4 is sent in the radial direction of the disk 1 by the turning of the turning mirror 7, and is also sent by the sending device 12 in the radial direction of the disk. The feed device 12 is a well-known mechanism including a feed motor and a movement direction conversion means for converting this rotation into a linear movement to linearly move the pickup 3. When the feeding by the turning mirror 7 becomes impossible, the feeding device 12 is generally used. Feeding by the feeding device 12 occurs.

The photodetector 10 of the pickup 3 is connected to a demodulation circuit 14 via a regenerative amplifier 13. The demodulation circuit 14 demodulates the EFM signal. The data processing circuit 15 connected to the demodulation circuit 14 includes a descrambling circuit, a dinterleave circuit, etc., and restores the same arrangement as that of a digital signal converted from an audio signal during recording. A DAC (digital-analog converter) 16 connected to the data processing circuit 15 converts a digital voice signal into an analog voice signal.

The audio level detection circuit 17 connected to the data processing circuit 15 sends data indicating whether or not the audio signal level is below a predetermined level to the first microcomputer (microcomputer) 18 based on the digital audio signal.

The first microcomputer 18 is called a system microcomputer, and has a CPU 19, a RAM 20 and a ROM.
21 and the like, the presence / absence of an audio signal is determined in accordance with a predetermined program, the end of song detection control, and the like are performed. This microcomputer 18
An operation key device 22 for specifying various modes of the CD player is connected to. This operation key device 22
Also functions as a read command means for reading the end time code of the music. A display device 23 for displaying subcode information such as a time code is connected to the first microcomputer 18. The time code is displayed on the display device 23 in units of hour, minute, second, and frame by a known method.

The subcode detection circuit 24 connected to the demodulation circuit 14 detects subcode data such as time code and music number, and sends it to the second microcomputer 25. The second microcomputer 25 is called a servo microcomputer, and drives the disk rotary motor 2 and the rotary mirror based on various commands and subcode detection signals given from the first microcomputer 18 via the data bus 26. The coil 11 and the feeding device 12 are controlled, and subcode data such as a time code is sent to the first microcomputer 18 by the bus 27.

FIG. 2 shows the relationship between the signal level and scanning when measuring the length of a song and the space between songs using the apparatus of FIG. 1, and FIG. 3 is a flow chart showing the procedure for determining the song end. .. When measuring the length of the music and the space between the music, the music to be measured is designated by the operation key 22. First
In response to this, the second microcomputer 18, 25 sends the light beam 4 to the track number (program number) of the specified track N on the disk 1.
Search NO.). That is, the light beam 4 fast-forwards and scans the track as shown by the arrow A1 in FIG. When the tune number N is detected, it is not used as the end of the tune and further scanned by normal feeding as shown by an arrow A2 to detect a position t1 at which the signal level of the tune N rises above a predetermined level L1. The recording position t0 of the song number is the recording start position t1 of the actual song.
It is very close to, but not necessarily coincident with, so that the voice level detection circuit 17 compares the predetermined level L1 with the detected voice signal level to accurately detect the music start position t1 from the actual voice signal level. When the actual start position of the song N is detected, the time code (absolute absolute time) at this point is read from the subcode data and written in the RAM 20 of the microcomputer 18. At the same time, the time is displayed on the display device 23 in units of hour, minute and second frame corresponding to the start time code.

Next, the end position t3 of the music N is searched. As described above, it is difficult to accurately detect the end position of a song by forward feed. Therefore, as shown by the arrow A3 in FIG. 2, the music piece number position t4 of the next music piece N + 1 is searched by fast forward.

Next, the actual start position t5 of the song N + 1 is detected by the fast-forward scanning shown by the arrow A4. The start end position t5 of the music N + 1 is determined based on the output of the voice level detecting circuit 17 similarly to the detection of the start end position t1 of the music N. When the start position t5 of the song N is detected, the time code at this point is RA
The data is written in M20 and simultaneously displayed on the display device 23.
If it is not necessary to measure the space between the music N and the music N + 1, the time code at the start position t5 is stored in the RAM.
Writing to 20 is not necessary.

Next, according to the flowchart of FIG.
The terminal position t3 of the is searched. That is, block 3 in FIG.
The program is started at 0, and the song end search is started as shown in block 31. As a result, as shown in block 32, high-speed reverse reproduction for a predetermined distance is executed. For example, as shown by the arrow B1 in FIG. 2, high-speed reverse reproduction is performed in the reverse direction for a distance slightly shorter than the inter-track space. Next, according to the block 33 of FIG. 3, the forward reproduction for a fixed time is executed. The arrow B2 in FIG. 2 indicates the scanning during the forward reproduction, which is shorter than the arrow B1. At the same time, the presence or absence of a voice signal is determined according to block 34. If there is no audio signal, the process returns to the block 32 again after the correct direction correction in the fixed time, and the same operation is repeated. Arrows B3 and B in FIG.
4, B5 and B6 indicate this repetitive operation. Since the reproduction in the forward direction is shorter than that in the reverse direction, the end position t3 is approached by the repetition of both. If the audio signal is detected by the backward reproduction of the arrow B5, the audio signal is detected by the subsequent forward reproduction of the arrow B6. Next, as shown in block 35 of FIG. 3, the end position t3 of the song N is detected. This detection is performed by obtaining the time point when the audio signal level becomes lower than the predetermined level L1. When the end position t3 is detected by the microcomputer 18, the time code at this time is written in the RAM 20 as shown in the block 36, and the time indicating the time code is displayed on the display device 23, and the block 37 is displayed.
The end search is ended as shown in. Since the time code A at the beginning of the song N, the time code B at the beginning of the next song N + 1 and the time code C at the end of the song N are written in the RAM 20, the actual time of the song is indicated by C-A. Then, the time of the space (non-recorded area) between the song N and the song N + 1 can be determined by B-C.

As is apparent from the above, in the present embodiment, when detecting the end position t3 of the music N, the start position t5 of the next music N + 1 or the reproduction position t4 of the music number N + 1 is detected, and reverse reproduction is performed. Since the end position of the music N is determined in combination with the direction reproduction, the end of the music can be detected easily and accurately. Further, the length of the song N and the space between songs can be easily and accurately determined.

[0021]

MODIFICATION The present invention is not limited to the above-described embodiments, and the following modifications are possible, for example. (1) The audio level detection circuit 17 can be connected to the output line of the DAC 16 and detected by an analog comparator. (2) Set the backward playback time indicated by arrow B1 in FIG. 2 longer than the expected inter-track space, detect the audio signal of song N in the first backward playback, and read the time code at this point. You can Also in this case,
To improve the accuracy of reading the time code at the end of the song,
It is possible to perform the forward direction reproduction after the backward direction reproduction by the extended arrow B1 and read the time code at the time when the audio signal disappears, and use the average of the time codes at the two music ends as the time code at the music end position t3. it can. As described above, the method of determining the time code of the song end by the average can be applied to the case of detecting the end by the arrows B5 and B6 in FIG. (3) In FIG. 2, the backward playback is started from the starting end position t5 of the next song N + 1. However, when it is not necessary to obtain the space between songs, the backward playback is started from the playing position t4 of the song number N + 1. Good.

[Brief description of drawings]

FIG. 1 is a block diagram showing a CD player according to an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between changes in the audio signal level of a song and scanning for detecting the beginning and end of the song.

FIG. 3 is a diagram showing a flow of an operation of detecting an end of a music piece.

[Explanation of symbols]

 1 disk 17 audio level detection circuit 18 microcomputer 24 subcode detection circuit

Claims (2)

[Claims] 1. A rotating device for a recording medium disc, wherein a plurality of information blocks are recorded with a space between each other and a time code is recorded, and for reading the information block and the time code from the disc. A signal converter, a feeding device for feeding the signal converter in the radial direction of the disk, a signal presence / absence determining unit for determining the presence / absence of a signal in the information block based on the output of the signal converter, End time code read command means for commanding to read the time code at the end of one selected information block, and the selection in response to the end time code read command from the end time code read command means. The signal converter at the beginning of the next information block of the stored information block, The feeding device is controlled to perform backward reproduction or combined reproduction of backward and forward directions from the start position of the block toward the end of the selected information block, and based on the output of the signal presence / absence determining means, A disk device comprising: end detection control means for determining the end of the selected information block and reading the time code at the end determination. 2. A plurality of information blocks are recorded with a space between them and a time code is recorded on the end of one information block arbitrarily selected from the plurality of information blocks in the recording medium disc. A method of reading a time code, the method comprising: detecting a start end of an information block next to the selected information block based on an output of the signal converter that reads the information block and the time code from the disc; Reverse reproduction or a combination reproduction of reverse reproduction and forward reproduction from the start end of the information block to the end of the selected information block, and the selected information block based on the output of the signal converter. Detecting the end of the disc and reading the time code at this time. Time information reading method in.