JPH0335749B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fast forwarding and fast reversing method in a digital audio disc player.

(Conventional Structure and Its Problems) The structure and problems of a conventional digital audio disc player will be described using a CD (compact disc) player as an example of fast-forwarding and fast-reversing methods.

Conventionally, the following methods are common for fast forwarding and fast reversing.

(a) While the disk rotates for a certain period of time or a certain rotation angle, the data recorded on the disk is read by an optical pickup using normal playback operations, and based on the read data, the song number, elapsed playing time, etc. are displayed. I do.

(b) Then, depending on whether it is fast-forward or fast-reverse, the track jumps a certain number of tracks toward the outer circumference or toward the inner circumference. During this track jump, the track number display and elapsed performance time display maintain the display immediately before the jump.

(c) Repeat the operations (a) and (b) above until an instruction to stop the fast-forward or fast-reverse operation is given.

However, in the above method, if the number of tracks to jump for fast forwarding and fast reversing is constant regardless of the radial position of the optical pickup disk, the disk rotation control method is constant linear velocity (CLV), The skip time width of the playback time (performance time) due to jumps is about 2.5 times different depending on whether the optical pickup is near the innermost circumference of the disc or near the outermost circumference. In order to reduce the difference in the skip time width to a level that does not pose a practical problem, there is a method of changing the number of tracks to be jumped depending on the radial position of the optical pickup disk, but this method requires complicated control. Furthermore, the skip time width and the like become irregular due to track jumps in the display contents. In order to reduce this skip time width, the number of tracks to be trackjumped may be reduced, but this will reduce the fast-forward and fast-reverse speeds.

(Object of the invention) The present invention solves the above problems.
In other words, when fast-forwarding or fast-reversing, the track number or elapsed playing time display can be continuously changed at a constant double the speed of normal playback, regardless of the radial position of the optical pickup disk, and the displayed contents can be To provide a method for fast forwarding and fast reversing a digital audio disk player in which the skip time width can be made small enough to cause no practical problems and the control method is simple.

(Structure of the Invention) Before describing the structure of the present invention, the track structure of a compact disk will be described. Tracks on a CD consist of a lead intra track, a music track, and a lead out track from the inner circumference of the disc.The lead intra track contains the disc catalog number, the total number of songs on the music track, During the music track, the play start time of the song number (time based on the music track start time: ATiME), the play time of each song number, etc. In addition to the audio data, data related to the audio data being played back, For example, the song number of the currently playing song, the elapsed playing time of that song (MTiME), the cumulative elapsed time since the beginning of the music track (ATiME), and the lead-out track indicate the end of the music track. Data indicating this is recorded.

Next, the configuration and operation of the present invention for achieving the above object will be described. First, since the hardware configuration is no different from a conventional general digital audio disk player, a description thereof will be omitted.

Next, we will outline the operation.

(A) At the start of playback (when the disc is loaded into the player), the total number of songs on the installed disc that accessed the lead intratrack, and the playback start time for each song number based on the music track start time. Read and store in designated RAM.

(B) During normal playback, the song number in the music track and the performance progress of that song number are always read and displayed. At the same time, the cumulative elapsed time (ATiME) based on the music track start point is also read and the contents of a predetermined RAM are updated.

(C) Even if a fast-forward or fast-reverse instruction is given, the currently playing song number (MN) during playback,
The operation of reading the elapsed playing time (MTiME) and cumulative elapsed time (ATiME) of the song and storing them in a predetermined RAM continues. However, audio output will be cut off. Further, the display content is updated (fast-forward or fast-reverse) from the display content immediately before the start of fast-forward or fast-reverse at a certain times the speed of normal playback.

(D) When the fast-forward or fast-reverse instruction stops, the display contents stop updating, and the currently displayed song number MN is played based on the display contents and the music track start point read from the lead intra track. Cumulative elapsed time (ATiME A=) to be accessed from start time (ATiME)
Calculate the performance start time of the currently displayed song number MN + currently displayed elapsed performance time), and calculate the number of tracks to jump from the cumulative elapsed time of the current position of the optical pickup (ATiME B) and ATiME A. After the access is completed, the playback state is restored (audio cutoff is stopped and the song number in the read data and the elapsed playing time of the song number are displayed).

Regarding the method of calculating the number of tracks to be jumped from the cumulative elapsed time of the current optical pickup position (ATiME B) and the cumulative elapsed time of the position to be accessed (ATiME A), and the specific access method using the result, see below. Traditionally, so-called “cue cueing” to access the starting point of a specified song number
Same as access.

(Explanation of Embodiment) In the following, regarding the embodiment of the present invention, the hardware configuration of the player is the same as the conventional one, so the explanation will be omitted. Focusing on the processing method of
This will be explained using figures.

Before entering into the explanation of the figure, the meaning of each label shown in the figure will be explained.

MN: Song number display content.

MTiME: Display content of the above song number Elapsed performance time display content of MN.

MTiME′: Performance time (length of song) of the above song number display content MN.

MTiME'': Performance time (length of song) of the song number (MN-1) immediately before the above song number display content MN.

ΔT: Unit update time width of elapsed performance time display during fast forwarding and fast rewinding.

MNMAX: Maximum song number recorded on the disk installed in the player.

MNMiN: The lowest song number recorded on the disk installed in the player (usually 1).

FFFLG: Flag that determines whether the fast forward or fast reverse key is pressed.

Further, it is assumed that the display contents MN and MTiME are only updated in this routine, and the display processing of the contents is performed in a separate routine.

Next, explanations of the figures will be given below.

When this routine is entered due to an interrupt, first, step 1 performs processing to enable an interrupt after a certain period of time (100 msec in this example), then step 2 determines whether the fast forward key is on or not. If it is on, 3 will turn MTiME on.
Determine whether it is greater than or equal to MTiME′. MTiME
If it is MTiME', MTiME exceeds the playing time of song number MN, so it is 4 and MN.
Compare MNMAX, if MNMNMAX,
MN is the last song number in the music track of the currently installed disk, so 5, 6
and the MTiME′ value as MTiME, and the MTiME′ value as MN.
After storing each MNMAX value, at 7
FFFLG is set and exits from the interrupt routine.

If it is determined in step 4 that MN<MNMAX,
Since the displayed song number has not yet reached the maximum song number (because there are song numbers that are not displayed yet), the display will be set to the time when the next song number starts playing.
After setting MTiME to φ at 8 and adding 1 to MN at 9,
Go to step 7 above.

Also, if MTiME<MTiME′ at 3, the elapsed playing time of the song number indicated by the current MN is smaller than the playing time (length of the song), so there is no need to update the MN yet, and simply set MTiME at 10. is increased by ΔT (here, ΔT/interrupt cycle is the magnification of the display content update speed during normal playback and fast forward (or fast rewind). If ΔT = 1 sec and interrupt cycle is 0.1 sec, the magnification is 10. ), proceed to step 7.

On the other hand, if it is determined in step 2 that the fast-forward key is not on, then in step 11 it is determined whether the fast-reverse key is on. If it is on, it is determined in step 12 whether MTiME is less than or equal to ΔT. If MTiMEΔT,
Since MTiME is almost at the playing start time of song number MN, MN and MNMIN are compared in step 13, and if MNMNMiN, MN is the first song number in the music track of the currently installed disk. Therefore, if the displayed content is fast-rewinded to the point where the first song number starts playing, it will be displayed at 14 and 15.
After storing φ as MTiME and MNMiN value as MN, go to step 7.

If MN > MNMiN in 13, the displayed song number is still the first song number, so in 16
Let MTiME be the performance time (length of the song) of song number MN-1 MTiME'', and at 17, MN is decremented by 1 and the process goes to 7 above.

Also, if it is determined in 12 that MTiME>ΔT, then MTiME−ΔT>φ, so in 18
Subtract ΔT from MTiME to make it MTiME, then jump to 7.

If neither the fast forward nor fast reverse keys are on,
19, check whether FFFLG=1 or not, FFFLG=
If it is 1, it means that the fast forward or fast reverse key was on until the last time this routine was interrupted, so if it is 20, the MN currently displayed
From the value MTiME and the performance start time (ATiME) of the song number MN read in the lead intratrack, calculate the ATiME (cumulative performance time when the music track start point is φ) corresponding to the MN and MTiME, that is, ATiME A. Also, the last ATiME read from disk at 21, i.e. ATiME
After calculating the number of tracks to be moved from B, at 27
Exit from the interrupt routine with FFFLG=φ.

Further, when it is determined in step 19 that FFFLG=φ, processing related to fast forwarding or fast reversing is deemed unnecessary, and the interrupt routine is exited without doing anything.

Furthermore, the operation of moving the optical pick-up to a position in the disk radial direction by the number of tracks to be moved calculated in step 21 is not performed in this interrupt routine, but in a separate routine that is the same process as the above-mentioned "cue" fast forward or "cue" fast rewind. Do it with

(Effects of the Invention) As described above, the fast-forwarding and fast-reversing method according to the present invention does not require any changes in the hardware configuration of the conventional digital audio disk player, but simply uses a sequence control method, that is, a microcomputer program that is executed by sequence control. By only making changes, the problems of the conventional system can be solved and an easy-to-use player can be realized.

[Brief explanation of the drawing]

The figure is a diagram showing an interrupt routine at fixed time intervals for updating the performance song number during fast-forwarding or fast-reversing and the elapsed performance time of the song number according to the present invention.

Claims (1)

[Scope of Claims] 1. Accessing the lead intratrack of a disk including a lead intratrack, a music track, and a leadout track, and determining the total number of songs,
The performance start time of each song number is read based on the music track start time, and the specified RAM is read.
During playback, it always reads and displays the station number in the music track and the elapsed playing time of that song number, and also reads the cumulative elapsed time based on the music track start point and reads the contents of the RAM. While updating steps and fast-forwarding or fast-reversing instructions are being given, reading and processing data from the disk will continue, but audio output will be cut off, and the track number and elapsed time will not be displayed. A step that continuously changes the speed from the previous value at a constant double the normal playback speed, and when the fast-forward or fast-reverse instruction is stopped, it stops updating the display contents and changes the currently displayed song. calculating the cumulative elapsed time to be accessed from the playing start time of the number, calculating the number of tracks to be jumped from the cumulative elapsed time at the current position of the optical pickup and the cumulative elapsed time to be accessed, and accessing is completed; A method for fast forwarding and fast reversing a digital audio disk player, comprising the steps of: restarting the display of the song number and elapsed time based on the audio output and the data read from the disk from the point in time.