JPH0534755B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fast forwarding method in an optical disc playback device such as a digital audio disc player.

Conventional Structure and Problems The structure and problems of a conventional fast-forwarding method in an optical disc playback device will be explained using a CD (compact disc) player as an example.

Conventionally, the following methods are common as fast forwarding methods. In other words, () While the disk rotates for a certain period of time or at a certain rotation angle, the data recorded on the disk is read by the pickup using normal playback operations, and () based on the data, the song number, elapsed playing time, etc. Display is performed, and in some cases, an audio signal is also output for a certain period of time including this period.

() Thereafter, depending on the direction of fast forwarding (inner or outer circumferential direction), the playback position is moved (track shift) in the radial direction of the disk by a fixed number of tracks toward the outer circumference or toward the inner circumference.

() During this track shift, the track number display and performance elapsed time display maintain the display immediately before the track shift, and the output of audio signals during this time is cut off.

() Repeat the above operation until an instruction to stop fast forwarding is given.

However, in the above method, since the CD rotation control method is constant linear velocity (CLV), the pick-up (and therefore the playback position) is near the innermost circumference of the disc during the skip time of the playback time (performance time) due to track jump. There is a difference of about 2.5 times between the case where it is located near the outermost circumference and the case where it is near the outermost periphery. In order to reduce this difference in time to a level that does not cause any practical problems, there is a method of changing the number of tracks to be shifted depending on the radial position of the pick-up disk.
Control becomes complicated.

Purpose of the Invention The present invention solves the above-mentioned problems. During fast forwarding, the track number or elapsed playing time is displayed regardless of the radial position of the pick-up disk.
It is always updated at a fixed speed of normal playback, and the skip time width of the displayed content can be kept almost constant regardless of whether the disk playback position is on the inner or outer side, and can be controlled in a relatively easy way. It is an object of the present invention to provide a fast forwarding method in an optical disc playback device.

Structure of the Invention Before describing the structure of the present invention for achieving the above object, the track structure of a compact disk will be described. CD tracks start from the inner circumference of the disc: lead intratrack, music track,
It is structured in the order of the lead-out track, and the center of the lead-in track is represented by the disc catalog number, the total number of songs on the music track, and the cumulative elapsed time (ATiME), which is address information starting from the music track start point. The performance time (length of the song) for each song number, etc., and data related to the audio signal being played in addition to the audio signal during music tracking, such as the song number of the song currently being played,
The elapsed performance time of the song, the cumulative elapsed time (ATiME) starting from the music track start point, and the like are recorded in the lead-out track, as well as data indicating that the music track has ended.

In order to achieve the above object, the present invention provides the following features: (A) When playback starts (when the disc is installed in the player), the lead intratrack is accessed, and the total number of songs recorded on the installed disc and the total number of songs to be played are obtained. The time required (ATiME maximum value), etc. are read and stored in the specified RAM.

(B) During normal playback, the song number and the elapsed playing time of that song are always read and part or all of this is displayed. At the same time, the cumulative elapsed time (ATiME) starting from the music track start point is read, and the contents of a predetermined RAM are updated each time the cumulative elapsed time is read.

(C) When a fast forward instruction is given, the cumulative elapsed time (ATiME) stored in the specified RAM is
The stored content immediately before the start of the fast-forward instruction is updated at a predetermined times the content update speed during normal playback.

Also, after a certain period of time from the start of the fast forward instruction, the updated cumulative elapsed time content ATiMEA is read, this is set as the destination address, and from this destination address and the cumulative elapsed time content ATiMEB read just before the start of fast forwarding, the updated cumulative elapsed time content ATiMEA is read. The number of tracks to be shifted and the direction in which the tracks should be shifted in order to move the playback position are calculated, and the tracks are shifted based on the results of this calculation. Here, from immediately after the start of the fast-forward instruction to the end of the track shift, no data is read from the disk, and therefore, audio output is cut off.

(D) Cumulative position and time content ATiMEA that continues to be updated after the track shift ends.
Read and use this as the new destination address. You can also pick up your current location from the disk.
Load ATiME (current location address information).
From these two addresses, the number of tracks to be shifted next and its direction are calculated.

Since it is possible to output audio during the calculation of the number of tracks to be shifted and their direction after reading the current location address, the interruption of audio output may be canceled for a certain period of time including the above period.

Next, while track shifting is performed based on the calculation result, since it is impossible to read data from the disk, audio output is cut off.

By repeating the above operation after the fast-forward instruction stops until the first track shift operation ends, or after the fast-forward instruction stops and until the destination address is accessed, the fast-forward operation ends and normal playback resumes. return to the state.

The method for calculating the number of tracks to be shifted from the destination address and current location address is as follows:
For example, there are the following methods.

A table of cumulative elapsed time (ATiME) and the corresponding number of tracks starting from the music track start point is prepared in advance, and the number of tracks TA corresponding to the ATiMEA of the destination address is prepared.
Find the number of tracks TB corresponding to ATiMEB of the current location address from the table above, find the difference in the number of tracks δT from δT=TA−TB, and find the number of tracks to be shifted by |
δT|, the direction in which the track should be shifted is the outer circumferential direction if δT>0, and the inner circumferential direction if δT<0.

In addition to reading the current location address and calculating the track shift direction and number of tracks from the two information of the destination address and current location address, it is possible to calculate the track shift direction and number of tracks from the two information of the destination address and the current location address. It is also possible to perform the update every time a certain amount (ie, a certain period of time) is performed.
In this case as well, audio can be output for a predetermined period of time including the time during which the current location address is read.

By operating as described above, the fast-forwarding speed is determined by the changing speed of ATiMEA, and the conventional problem of changing the fast-forwarding speed between the inner and outer circumferential sides is eliminated.

DESCRIPTION OF EMBODIMENTS Hereinafter, one embodiment of the present invention will be described based on the drawings. Since the hardware configuration of the player is no different from the conventional one, the explanation will be omitted, and FIG. The direction in which tracks should be shifted, the calculation of the number of tracks, and the method of reading ATiMEB will be explained with reference to FIG.

Before explaining FIGS. 1 and 2, the meaning of each label shown in FIGS. 1 and 2 will be explained.

ATiMEA: During normal playback, this is the ATiME value at the playback position, and during fast forwarding, this is the ATiME value that is updated at a predetermined times the speed of normal playback, and serves as the destination address.

ATiMEB: Same as ATiMEA during normal playback. During fast forwarding, the ATiME value is read intermittently,
This will be your current location address.

ATiME′: Time required to play all songs on the disc installed in the player (ATiME maximum value).

ΔT: ATiMEA unit update time width during fast forwarding.

FFFLG: A flag that is set to "1" when a fast-forward instruction (inner or outer direction) is issued, and "0" when it is not issued (a flag for determining whether a fast-forward instruction is being issued).

FFLG: Flag set to “1” while a fast-forward instruction is issued and from the time the fast-forward instruction is canceled until the fast-forward operation is completed, and “0” during other times (flag for determining whether fast-forward operation is in progress) ).

Next, FIG. 1 will be explained. When this routine is entered due to an interrupt, first, in (1), processing is performed to enable the next interrupt after a certain period of time (for example, after 50 msec), and then, in (2), a fast-forward instruction is issued in the outer circumferential direction. If the instruction has been given, it is determined in (3) whether ATiMEA is greater than or equal to (ATiME′−ΔT), and if it is, ATiMEA has reached the full performance time. Assuming that, in (4), ATiMEA is
Store ATiME′. Also ATiMEA<
If (ATiME′−ΔT), ATiMEA has not reached the full performance time, so (5)
ΔT is added to make this a new ATiMEA, and in (6), FFFLG is set to "1" and the interrupt routine is exited.

If in (2) it is assumed that the outer circumferential direction fast-forwarding instruction has not been given, then in (7) it is determined whether or not the inner circumferential direction fast-forwarding instruction has been made, and if the instruction has been given, in (8), It is determined whether ATiMEA is less than or equal to ΔT, and if it is less than or equal to ΔT, it is assumed that the value of ATiMEA has reached 0, and 0 is stored in ATiMEA in (9). Also
If ATiMEA>ΔT, the value of ATiMEA is 0
Since ΔT has not been reached, subtract ΔT from ATiMEA in (10) and use this as a new ATiMEA.

(9) Also, after the process of (10) is completed, the process moves to the process of (6) above.

If it is determined in (7) that a fast-forward instruction has not been given in the inner direction, it is determined that a fast-forward instruction has not been given in either the inner or outer direction (or has ended), and in (11)
Set FFFLG to 0 and exit from the interrupt routine.

Here, in process (1), when performing processing to enable the next interrupt after a certain period of time, this time is set large at the start of fast forwarding, and is gradually decreased for each interrupt. It is also possible to start fast forwarding slowly and increase the speed as time passes.

Next, the calculation of the direction in which tracks should be shifted and the number of tracks from the values of ATiMEA and ATiMEB, and the method of reading ATiMEB will be explained with reference to FIG.

As mentioned above, in the process of FIG. 1 which is a time interrupt routine, while a fast forward instruction is given,
FFFLG is set. In the processing routine of FIG. 2, which is part of the background grant routine,
First, in (12), determine whether FFFLG is “1” or not,
If it is “1”, it is assumed that fast forwarding is in progress, and in (13), ATiMEA (destination address) and
Calculate the track to be shifted and the direction of shift from ATiMEB (current location address), and set this in a predetermined RAM and output port. After that, in order not to read the incorrect current location address ATiMEB during track shift (14),
In (15), FFLG is set to "1", and in (16), a track shift is performed in a separate routine by the number of tracks previously set in (13).

After detecting "track shift number = 0" in (16),
That is, after the track shift by the number of tracks set in (13) is completed, in (17), the previously set read prohibition of ATiMEB is canceled and the process waits for the completion of reading of ATiMEB, which is executed in a separate routine. When loading is completed, the above (12)
Return to processing.

If FFFLG = 0 in (12) (the fast-forward instruction has been canceled), it is determined in (19) whether FFLG = 1, and if FFLG = 1, the fast-forward instruction has been canceled. , it is assumed that the fast-forward operation has not been completed, and in (20) ATiMEB and ATiMEA are compared, and if they are the same, fast-forward is completed, the track value to be shifted is set to 0 in (21), and in (22)
Set FFLG to 0 and move on to other processing routines.

In (21), if ATiMEA = ATiMEB, then
Proceed to process (13) (although it is different from the flow in Figure 2)
When FFFLG=0 and FFLG=1, ATiMEA
Regardless of whether it matches ATiMEB or not,
In other words, it is also possible to move on to the process in (21) without making the determination in (20).)

In (19), when FFLG=0, since fast forwarding is not in progress, no processing is performed and the process moves to other processing.

Although the operation and embodiments of the structure of the present invention have been described above using a CD player as an example, it goes without saying that other optical disc playback devices can be configured in exactly the same way.

Effects of the Invention As described above, according to the present invention, the problem of the conventional rapid traverse method, which is the change in the rapid traverse speed on the inner circumferential side and the outer circumferential side, is solved, or a rapid traverse method for eliminating this change is provided. Accordingly, it is possible to solve the complexity of the system, and to realize a digital audio disc player that is easy to control and easy to use.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of an interrupt routine at fixed time intervals for fast forwarding (updating at a predetermined speed twice that of normal playback) the accumulated elapsed time content ATiMEA, which is the target address during fast forwarding according to the present invention. , Figure 2 constitutes a part of the background routine,
Said destination address ATiMEA and location address
FIG. 7 is a configuration diagram showing an example of a processing routine for calculating the number and direction of tracks to be shifted from ATiMEB and prohibiting/permitting reading of the current location address.

Claims (1)

[Claims] 1. During playback, the address information (ATiME) of the playback position is read from the disk and stored at regular intervals, and after a fast forward instruction is issued, the read and stored address information value is issued as a fast forward instruction. The address information value is continuously changed (increased or decreased) from the previous value at a change rate that is twice as fast as normal playback.
ATiMEA is obtained, and the number of tracks to be moved and the direction of movement are calculated based on the address information value ATiMEA after the elapse of a predetermined time after starting fast forwarding and the address information value ATiMEB read from the disk immediately before starting fast forwarding. A track shift is performed to move the playback position in the radial direction of the disk, and when the track shift is completed, the address information value at the position after the track shift is read from the disk and used as the new current location address information value.
ATiMEB, and reads information to be displayed such as the song number and elapsed playing time at the position after the track shift from the disk and displays it.
and an address information value that continuously changes at a rate of change that is a predetermined times that of normal playback even during the above operation.
The current value of ATiMEA is used as the new destination address, and the number of tracks to be shifted and the direction of the shift are calculated based on the two information of the current location address and the destination address, and the track shift is performed. A fast-forwarding method in an optical disc reproducing apparatus, characterized in that track shifting is performed continuously, and track shifting is completed when the current location address and the destination address match after the fast-forwarding instruction is canceled. 2. The optical system according to claim 1, wherein the cutoff of the playback output is released for a certain period of time after the track shift ends during fast forwarding, and after the elapse of the certain period of time, the playback output is cut off and the track shift is started. Fast-forwarding method in a disc playback device.