DISK PLAYING METHOD FOR MULTIDISK PLAYER

Abstract: A method for playing tunes from a plurality of disks stored in a magazine in random order and without repeating any one tune. Three memories are provided. In the first there are recorded the identities of disks which have already been played, in the second, the identities of already-played tune S on each disk, and, in the third, an incremental count of the number of already-played tunes on each disk. The tunes are selected in terms of random numbers limited by the number of as-yet-­ unplayed disks derived from the data stored in the first memory.

Description: The present invention relates to a disk playing method for a multi-disk player in which a plurality of disks are housed in a magazine, and the disks can be randomly extracted from the magazine and played. A multi-disk player, in which a plurality of compact disks are housed in a magazine and the disks are sequentially extracted from the magazine and reproduced, has been proposed, manufactured and put on the market by the present applicant. In this multi-disk player, a plurality of compact disks can be continuously played in the sequence in which the disks are housed in the magazine, in the sequence in which tunes are recorded, in an optionally programmed sequence of disks, in an optionally programmed sequence of recorded tunes, or in the like. However, the playing sequence of the disks is fixed at the start of the playing operation. For that reason, this disk method has the disadvantage that the selection of tunes cannot be done spontaneously. There is also a demand for a multi-disk player which can play disks for background music or the like in a random sequence upon simply turning on the main switch of the player. From EP-A-0177088 it is known to randomly select a disk and thereafter play all the tunes on that disk in a random order before selecting a new disk. EP-A-0217112 (Art. 54(3) EPC) discloses a method of randomly selecting a disk and then randomly selecting only one tune from that disk before the next disk is selected. The method does not keep track of tunes that have been played to avoid that the same tune is played twice. According to the present invention a disk playing method for a multi-disk player in which a plurality of disks are housed in a magazine and the disks are pulled out and played, comprises the steps of: a) providing a first memory for recording an indication of the completion of playing of each of the disks, a second memory for recording identities of already-played tunes on each of the disks, and a third memory for recording an incremental count of the number of the already-played tunes on the disks; b) randomly selecting an as-yet-unplayed disk in accordance with a random number and on the basis of the contents of the first memory; c) determining whether the randomly selected disk is present; d) when the disk is not present, recording information on the result of the determination in the first memory, and when it is determined that the disk is present, reading information indicative of the number of all the tunes on the disk from the disk and the number of already-played tunes from the third memory; e) subtracting the number of already-played tunes read from the third memory from that of all the tunes on the disk, when the result of the subtraction is one, recording the forthcoming completion of the playing of the disk in a corresponding already-played disk recording region in the first memory, and when the result of the subtraction is two or more, randomly selecting an as-yet-unplayed tune on the disk in accordance with a random number and on the basis of the contents of the second memory, and recording the forthcoming completion of the playing of the randomly selected tune in the second memory; and f) when the playing of the randomly selected tune is completed, repeating steps b) to f) until the contents of the first memory indicate that all tunes on all the disks have been played. According to a further aspect of the present invention a multi-disk player in which a plurality of disks are housed in a magazine and the disks are capable of being pulled and played, comprises (a) a first memory for recording an indication of the completion of playing of each of the disks, a second memory for recording identities of already played tunes in each of the disks, and a third memory for recording an incremental count of the number of already played tunes on the disks; (b) means for randomly selecting an as-yet-unplayed disk in accordance with a random number and on the basis of the contents of the first memory; (c) means for determining whether the randomly selected disk is present; (d) means for, when the disk is not present, recording information on the result of the determination of the first memory, and when it is determined that the disk is present, reading information indicative of the number of all the tunes on the disk from the disk and the number of already played tunes from the third memory; (e) means for subtracting the number of already-played tunes read from the third memory that of all the tunes on the disk, when the result the subtraction is one, recording the forthcoming completion of the playing of the disk in a corresponding already-played disk region in the first memory, and when the result of the subtraction is two or more, randomly selecting an as-yet-unplayed tune on the disk in accordance with a random number and on the basis of the contents of the second memory, and recording the forthcoming completion of the playing of the randomly selected tune in the second memory; and (f) means for repeating use of means b) to f) when the playing of the randomly selected tune is completed, until the contents of the first memory indicate that all the tunes on all the disks have been played. In the accompanying drawings: Fig. 1 shows a block diagram describing an embodiment of the present invention; Fig. 2 is a flowchart of the control sequence used in the Fig. 1 embodiment; and Fig. 3 shows a map of a memory for recording already-played disks and already played tunes. Fig. 1 is a block diagram of a multi-disk player. Shown at 1 in Fig.1 is a magazine capable of housing six compact disks. Shown at 2 in Fig. 1 is a reproduced disk horizontally pulled out of the magazine 1 and clamped on the spindle of a motor 15 so as to be rotated for reproduction. Laser light from an optical pickup 3 is directed upon the reproduced disk 2 to read the signal recorded on the disk 2. The signal read from the disk 2 by the pickup 3 is amplified by an RF amplifier 4 and demodulated by a decoder 5, the output from which is supplied to a data extraction circuit 6 in which address information is extracted and supplied to a controller 7. The controller 7 is connected to a random number generator 8 and a memory 9 including a first memory section A for recording identifying data for already-reproduced disks, a second memory B for recording identifying data for already-reproduced tunes on each disk, and a third memory C for storing an incremental count of the number of the already-reproduced tunes on each disk. The controller 7 is also connected to a pickup control motor drive circuit 10 and a disk change motor drive circuit 12. A drive signal is supplied from the controller 7 to the pickup control motor drive circuit 10 so that a pickup moving mechanism (not shown in the drawings) is driven by a pickup control motor 11. A drive signal is supplied from the controller 7 to the disk change motor drive circuit 12 so that a disk change mechanism, which extracts an optionally selected disk from among the disk stored in the magazine 1 and clamps the extracted disk on the spindle of the motor 15, is driven by a disk change motor 13. Fig. 2 shows a flowchart describing the operation of the controller 7. Fig. 3 shows a memory map describing the operation of the controller 7. The operation of this embodiment of the inventive multi-disk player will now described with reference to Figs. 1, 2 and 3. When a random reproduction start command is issued upon turning on a start switch (not shown), the controller 7 clears the contents of all of the first, second and third memories A, B and C of the memory 9 in a step 1. As described above, the first memory records the completion of the reproduction of each of the disks, and for this purpose has six bits corresponding to the six disks in the magazine 1. For a disk whose tunes have all already been played, the respective one of the six bits is set at "1". The second memory B records the completion of the reproduction of the various tunes on the disks, and has ninety-nine bits for a respective maximum of ninety-nine tunes on each disk. Each of the ninety-nine bits is set to "1" when the respective tune has been played. The third memory C stores a count of the number of the already-played tunes of each disk. The count is increased by one every time one tune is reproduced. When one the of tunes of one on the disks is being played in a random reproduction mode, address information, inclusive of a disk number and a tune number compiled by the data extraction circuit 6, is read by the controller 7 in step 2 and compared with previously stored address information to judge in step 3 whether or not the playing of the tune has been completed. When it is judged in step 3 that the playing of the tune has been completed, the controller 7 checks the contents of the first memory A to judge in a step 4 whether or not the playing of all disks has been completed. When it is judged in step 4 that the playing of all disks has been completed, it is judged in a step 5 whether or not the repetition of random playing has been instructed. When it is judged in step 5 that the repetition of random has been commanded, the above process is repeated from step 1. When it is judged in the step 5 that repetition or random playing has not been instructed, all operations of the multi-disk player are stopped. If it is judged in step 4 that the playing of all disks has not been completed, the number of the as-yet-unplayed disks, as stored in the first memory A, is counted in step 6, and a random number not larger than the counted number is then created by the random number generator 8. To create the random number by the random number generator 8, the output count of a counter which rapidly changes at a prescribed period is latched at an arbitrary timing and restricted by a limiter to the number of the as-yet-unplayed disks in step 7. For example, if the number of as-yet-unplayed disks is four, the number of one of the four as-yet-unplayed disks is extracted. In step 8, the "1" bits of the first memory A are counted, and the bits corresponding to the as-yet-unplayed disks are counted according to the value of the random numbers so that the number of one of the unplayed disks is randomly set. It is thereafter judged in step 9 whether or not the randomly calculated number is equal to the number of the currently played disk. When it is judged in step 9 that the randomly calculated number is equal to the number of the currently played disk, step 19 is playing. When it is judged in step 9 that the randomly calculated number is not equal to the number of the currently placed disk, the reproduction of the disk is stopped in step 10. In that case, the controller 7 commands the disk change motor drive circuit 12 to return the disk to the magazine 1 using the disk change mechanism 14, and the disk having the randomly calculated number is selected and clamped on the spindle of the motor 15 by the same mechanism in step 11. A command is then applied to a servo circuit for the motor 15, the optical pickup 3, etc., so that the servo system is actuated in step 12. At that time, the locking of the focusing servo mechanism for the optical pickup 3 is detected. Depending on whether the detected locking is OK (i.e., locked) or NG (i.e., not locked), it is judged in step 13 whether or not the disk corresponding to the number randomly calculated in step 8 is present in a tray located in the magazine 1 and corresponding to the randomly calculated number. If it is judged in step 13 that the disk is not present in the tray, the bit of the first memory A, which corresponds to the disk, is set at "1" so that an indication of the completion of the playing of the disk is stored in the memory in step 14. Another number is then randomly calculated in steps 15, 16 and 17, similarly to steps 6, 7 and 8, and step 10 is executed again. When the disk is judged to be present on the tray and the focusing servo mechanism is properly actuated in steps 12 and 13, recorded tune number information (hereinafter referred to as TOC information) recorded on the innermost portion of the recording region of the disk is obtained through the data extraction circuit 6 in step 18. In step 19, the controller 7 subtracts the number of the already-played tunes on the disk, which number is stored in the third memory C, from the number of all the tunes on the disk, which is obtained from the TOC information, to calculate the number of the as-yet-unplayed tunes on the disk. When it is judged in step 20 that the number of the as-yet-unplayed tunes is one, the bit of the first memory A corresponding to the disk is set to "1" to store an indication of the forthcoming completion of the playing of the disk in the memory in step 21 to complete the playing of all the tunes on the disk upon completion of the current playing operation. Step 22 is then executed. If it is judged in step 20 that the number of the as-yet-unplayed tunes on the disk is two or more, step 21 is skipped and the number of the already-played tunes on the disk, which is stored in the third memory C, is increased by one in step 22. Subsequently, a random number not larger than the number of the as-yet-unplayed tunes, which is calculated in step 19, is created by the random number generator 8. To create the random number with the random number generator 8, the count of a counter which rapidly changes at a prescribed period is latched at an arbitrary timing and restricted by a limiter in step 23 so that calculation is limited to or below a numerical value corresponding to the number of the as-yet-unplayed tunes. In step 24, the bits of the second memory B for the disk are counted and the appropriate bits for the as-yet-unplayed tunes are counted according to the value of the random number so that the number of one of the unplayed tunes is randomly selected. In stop 25, the bit of the second memory section B which corresponds to the tune of the disk is set to "1" so that the forthcoming completion of the playing of the tune is stored in the memory. When the number of the tune to be played next has been randomly calculated as described above, the controller 7 issues a command to the pickup control motor drive circuit 10, etc., to search for the tune in step 26 and to start playing the tune. Step 2 is thereafter again executed to repeat the same operations. For a random playing, step 1 is repeated if all the disks have been already-played, or step 6 is executed again if not all the disks have been played. Although the third memory C constitutes an unplayed tune counter in the above-described embodiment and is used to determine the number of the unplayed tunes on each disk, the present invention is not limited thereto and may be otherwise embodied so that the third memory C is not provided and the number of the unplayed tunes is calculated by counting the "0" bits in the second memory B. The once-read TOC information may be all stored in the memory so as to perform the same operation without having to read the TOC information again. Moreover, although the above-described embodiment relates to a multi-disk player for compact disks, the present invention is not limited thereto and may be also applied to a video disk player. In the disk playing method providing in accordance with the present invention, each disk is randomly selected and the number of tunes on the randomly selected disk is thereafter read the tunes are selected in such a manner as to randomly play all tunes on all disks without playing any tune twice. Since the already-played disks and the already-played tunes are allotted to specific bits of a memory, the capacity of the memory can be minimized. The invention also includes a multi-disk player provided with means for carrying out the new method.

Claims: A disk playing method for a multi-disk player in which a plurality of disks (2) are housed in a magazine (1) and the disks are pulled out and played, comprising the steps of: (a) providing a first memory (9A) for recording an indication of the completion of playing of each of the disks (2), a second memory (9B) for recording identities of already-played tunes on each of the disks, and a third memory (9C) for recording an incremental count of the number of the already-played tunes on the disks; (b) randomly selecting an as-yet-unplayed disk (2) in accordance with a random number and on the basis of the contents of the first memory (9A); (c) determining whether the randomly selected disk (2) is present; (d) when the disk (2) is not present, recording information on the result of the determination in the first memory (9A), and when it is determined that the disk is present, reading information indicative of the number of all the tunes on the disk from the disk and the number of already-played tunes from the third memory (9C); (e) subtracting the number of already-played tunes read from the third memory (9C) from that of all the tunes on the disk, and, when the result of the subtraction is one, recording the forthcoming completion of the playing of the disk in a corresponding already-played-disk recording region in the first memory (9A), and, when the result of the subtraction is two or more, randomly selecting an as-yet-unplayed tune on the disk in accordance with a random number and on the basis of the contents of the second memory (9B), and recording the forthcoming completion of the playing of the randomly selected tune in the second memory (9B); and (f) when the playing of the randomly selected tune is completed, repeating steps (b) to (f) until the contents of the first memory (9A) indicate that all tunes on all the disks (2) have been played. A disk playing method according to claim 1, further comprising the step of clearing all of the memories (9A, 9B, 9C) at a start of a multi-disk playing operation. A disk playing method according to claim 1 or claim 2, wherein the first memory (9A) is provided with a single bit for each of the disks (2). A disk playing method according to any one of the preceding claims, wherein the second memory (9B) is provided with one bit for each of a maximum number of tunes on any of the disks (2). A disk playing method according the any one of the preceding claims, wherein the step of randomly selecting an as-yet-unplayed tune comprises generating a random number not larger than the number of as-yet-unplayed disks (2) as indicated by the data recorded in the first memory (9A). A disk playing method according to claim 5, wherein the step of generating the random number comprises latching the output of a continuously operating counter at an arbitrary timing and restricting the value latched in accordance with the number of as-yet-unplayed disks (2). A multi-disk player in which a plurality of disks (2) are housed in a magazine (1) and the disks are capable of being pulled out and played, comprising; (a) a first memory (9A) for recording an indication of the completion of playing of each of the disks (2), a second memory (9B) for recording identities of already played tunes in each of the disks, and a third memory for recording an incremental count of the number of already played tunes on the disks; (b) means for randomly selecting an as-yet-unplayed disk (2) in accordance with a random number and on the basis of the contents of the first memory (9A); (c) means for determining whether the randomly selected disk (2) is present; (d) means for, when the disk (2) is not present, recording information on the result of the determination of the first memory (9A), and when it is determined that the disk is present, reading information indicative of the number of all the tunes on the disk from the disk and the number of already played tunes from the third memory (9C); (e) means for subtracting the number of already-played tunes read from the third memory (9C) from that of all the tunes on the disk, and, when the result the subtraction is one, recording the forthcoming completion of the playing of the disk in a corresponding already-played disk region in the first memory (9A), and when the result of the subtraction is two or more, randomly selecting an as-yet-unplayed tune on the disk in accordance with a random number and on the basis of the contents of the second memory (9B), and recording the forthcoming completion of the playing of the randomly selected tune in the second memory (9B); and (f) means for repeating use of means (b) to (f) when the playing of the randomly selected tune is completed, until the contents of the first memory (9A) indicate that all the tunes on all the disks have been played. A multi-disk player according to claim 7, further comprising means for clearing all of the memories (9A, 9B, 9C) at a start of a multi-disk playing option. A multi-disk player according to claim 7 or claim 8, wherein the first memory (9A) is provided with a single bit for each of the disks (2). A multi-disk player according to any one of claims 7 to 9, wherein the second memory (9B) is provided with one bit for each of a maximum number of tunes on any of the disks (2). A multi-disk player according to any one of claims 7 to 10, wherein the means for randomly selecting an as yet unplayed tune comprises means for generating a random number not larger than the number of as-yet-unplayed disks (2) as indicated by the data recorded in the first memory (9A). A multi disk player according to claim 11, wherein the means for generating the random number comprises means for latching the output of a continuously operating counter at an arbitrary timing and means for restricting the value thus latched in accordance with the number of as-yet-unplayed disks (2).

Inventors: MASAKI, NAOKI, Masaki, Naoki, c/o Pioneer Electronic Corporation
Applicants: PIONEER ELECTRONIC CORPORATION
Application year: 1987
Main classification: G11B27
IPC codes: G11B27, G11B17