Apparatus for reproducing program data recorded on an optical disc at a multiple velocity

An apparatus for reproducing program data recorded on an optical disc at a multiple velocity without a deterioration of a screen quality is disclosed. Storing section stores data which relates to rotation and reproduction velocity for normal and multiple velocity reproductions of the optical disc. Maincontroller checks whether or not a reproduction mode signal indicates the multiple velocity reproduction, and outputs rotation and reproduction velocity data signals corresponding to the checked reproduction mode signal. Velocity controller outputs rotation and reproduction velocity control signals and a memory control signal corresponding to the checked reproduction mode signal based on the rotation and reproduction velocity data signals. Rotating section rotates the optical disc at a rotation velocity determined by a present reproduction velocity signal and the rotation velocity control signal. Reproducing section reproduces the program data at a reproduction velocity determined by the reproduction velocity control signal and provides the present reproduction velocity signal to the rotating section. Memory stores the program data from the reproducing section and output the stored program data in response to the memory control signal. The rotation velocity of the optical disc and the reproduction velocity of the program data are variably controlled. The reproduced program data is stored in the memory and the stored program data is sequentially outputted. Consequently, the apparatus can prevent the deterioration of the screen quality caused by reproducing the program data recorded on the optical disc at the multiple velocity.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to an optical disc player, and more
 particularly, to an apparatus for reproducing program data recorded on an
 optical disc at a multiple velocity, which is capable of preventing
 deterioration of a screen quality even though a user reproduces the
 program data at the multiple velocity which is faster than a normal
 reproduction velocity.
 2. Description of the Prior Art
 In general, optical discs can be divided into discs for exclusive use of
 reproduction, discs for use of an additional record, and discs for use of
 erasing and rewriting according to functions and uses thereof.
 The reasons these kinds of optical disc players are widely used are that
 they can reproduce signals with far better quality of picture and/or sound
 and that it is possible for them to randomly access to program data to be
 reproduced. In addition to these reasons, there is other reason that noise
 arising from unstable reproduction and modulation does not occur.
 Furthermore, unlike a video cassette recorder or a cassette recorder, these
 optical disc players can directly move an optical pick-up unit toward a
 target track position in order to reproduce the data which is recorded on
 the optical disc within a very short time.
 FIG. 1 is a view for showing a screen arrangement type of a group of
 picture (hereinafter, referred to as GOP) conventionally recorded on an
 optical disc. As shown in FIG. 1, in the program data recorded on the
 optical disc, I pictures are arranged at regular intervals. The program
 data such as B pictures and P pictures are arranged between the two I
 pictures to make one GOP.
 FIG. 2 is a block diagram for showing a circuit diagram of an prior
 apparatus for reproducing program data at multiple velocity.
 Referring to FIG. 2, the reproducing apparatus has a key inputting section
 10, a control section 20, a reproducing section 30, a spindle motor
 driving section 40, and a spindle motor 50.
 When a user operates a key of key inputting section 10 to generate a
 reproduction signal, optical disc D is rotated at a constant linear
 velocity and the program data recorded on optical disc D is reproduced at
 a normal velocity. At this time, when a reproducing key signal from key
 inputting section 10 generated by the user's key operation indicates a
 multiple velocity, control section 20 detects a position of the I picture
 of the program data reproduced from optical disc D by reproducing section
 30.
 When the position of the I picture is detected, control section 20 controls
 reproducing section 30 to read out or skip I pictures following the
 detected I picture according to the reproducing key signal indicating the
 multiple velocity. That is, when the reproduction key signal indicating
 the multiple velocity is a reproduction key signal indicating twice
 velocity, as shown in FIG. 2, control section 20 controls reproducing
 section 30 to read out the I pictures by skipping one by two after
 detecting a first I picture. When the reproduction key signal indicating
 multiple velocity is a reproduction key signal indicating three times
 velocity, control section 30 detects only one out of three I pictures
 after detecting the first I picture.
 Accordingly, the program data recorded on optical disc D is possible to be
 reproduced at the multiple velocity even though optical disc D being
 rotated by spindle motor driving section 40 and spindle motor 50 rotates
 at the constant linear velocity.
 However, the reproducing apparatus described above causes a loss of the
 program data because of skipping other I pictures among the respective I
 pictures for reproducing the program data at multiple velocity.
 Consequently, a screen quality of the program data reproduced from
 reproducing section is deteriorated.
 SUMMARY OF THE INVENTION
 Therefore, it is an object of the present invention to provide an apparatus
 for reproducing program data recorded on an optical disc at a multiple
 velocity, which is capable of preventing deterioration of a screen quality
 even though a user reproduces the program data recorded on the optical
 disc at the multiple velocity which is faster than a normal reproduction
 velocity.
 In order to achieve the above object, the present invention provides an
 apparatus for reproducing data recorded on an optical disc at a multiple
 velocity, which comprises:
 storing means for storing data which relates to a rotation velocity for
 normal and multiple velocity reproductions of the optical disc and to a
 reproduction velocity of the program data recorded on said optical disc;
 control means for detecting whether or not a reproduction mode signal
 generated by a user's key operation is either the normal velocity
 reproduction or the multiple velocity reproduction, for reading out the
 rotation and the reproduction velocity data corresponding to the detected
 reproduction mode signal from said storing means to output rotation and
 reproduction velocity data signals;
 clock generating means for generating a reference clock signal;
 velocity control means for receiving the reference clock signal and for
 dividing the reference clock signal based on the rotation and reproduction
 velocity data signals to output rotation and reproduction velocity control
 signals and a memory control signal corresponding to the detected
 reproduction mode signal;
 rotating means for receiving a present reproduction velocity signal and for
 rotating said optical disc at a rotation velocity determined by the
 present reproduction velocity signal and the rotation velocity control
 signal;
 reproducing means for reproducing the program data recorded on said optical
 disc at a reproduction velocity determined by the reproduction velocity
 control signal and for providing said rotating means with the present
 reproduction velocity signal which represents a presently-reproduced
 velocity of the program data; and
 a memory for storing the program data from said reproducing means and for
 outputting the stored program data in response to the memory control
 signal.
 In the present invention, the velocity control means variably outputs a
 period of clock pulses of the reference clock signal based on the rotation
 and the reproduction velocity data.
 In the apparatus for reproducing the program data recorded on the optical
 disc at the multiple velocity according to the present invention, the
 rotation velocity of optical disc D and the reproduction velocity of the
 program data recorded on optical disc D are variably controlled in
 accordance with the user's key operation. Also, the program data
 reproduced at the multiple velocity is outputted to a display apparatus
 after the program data is sequentially stored in memory. Accordingly, the
 loss of the program data which is reproduced from optical disc D does not
 occurred even though the user selects a mode for reproducing the program
 data recorded on optical disc D at the multiple velocity.
 Therefore, the apparatus can prevent the deterioration of the screen
 quality caused by reproducing the program data recorded on optical disc D
 at the multiple velocity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 A description will be given below in detail with reference to accompanying
 drawing to a configuration and an operation of an apparatus for
 reproducing program data recorded on an optical disc at a multiple
 velocity according to embodiments of the present invention.
 FIG. 4 is a block diagram for showing a circuit configuration of an
 apparatus for reproducing program data recorded on an optical disc at a
 multiple velocity according to the one preferred embodiment of the present
 invention.
 Referring to FIG. 4, the apparatus for reproducing program data recorded on
 the optical disc at the multiple velocity according to the present
 invention has a key inputting section 100 for generating key signals in
 response to a user's key operation, a storing section 110 for storing
 rotation and reproduction velocity information of an optical disc D, a
 maincontroller 120 for controlling an operation of the reproducing
 apparatus in response to the key signals from key inputting section 100, a
 clock generator 130 for generating a reference clock signal, a velocity
 controller 140 for generating control signals in order to a control the
 rotation and reproduction velocity of optical disc D in response to
 control of main-controller 120, a rotating section 150 for rotating
 optical disc D in response to the control of velocity controller 140, a
 reproducing section 160 for reproducing the program data recorded on
 optical disc D in response to control of velocity controller 140, and a
 memory 170 for storing and outputting the program data from reproducing
 section 160 in response to velocity controller 140.
 Key inputting section 100 has keys. Key inputting section 100 provides
 maincontroller 120 with key signals such as a reproduction signal, a stop
 signal and a skip signal in response to the user's key operation. At this
 time, key inputting section 100 has keys for multiple reproduction for
 reproducing the program data recorded on optical disc D.
 Storing section 110 stores the rotation velocity information for rotating
 optical disc D and the reproduction velocity information for reproducing
 the program data recorded on optical disc D. At this time, the rotation
 and reproduction velocity information are detected by an experiment and
 become an optimized constant linear velocity corresponding to various
 reproduction velocities provided from the multiple velocity apparatus.
 Storing section 110 provides the rotation and reproduction velocity
 information to main-controller 120 in response to the control of
 maincontroller 120.
 MainController 120 generates control signals for controlling the respective
 elements of the reproducing apparatus in response to the key signals
 generated from key inputting section 100 by the user's key operation.
 Velocity controller 140 receives the reference clock signal from clock
 generator 130, and divides the reference clock signal according to the
 control signal from main-controller 120 to output rotation and
 reproduction velocity control signals and a memory control signal. At this
 time, velocity controller 140 consists of a clock divider.
 Rotating section 150 has a rotation velocity controller 151, a spindle
 motor driver 152 and a spindle motor 153. Rotation velocity controller 151
 variably outputs a rotation velocity signal for rotating optical disc D
 according to the rotation velocity control signal from velocity controller
 140 and a present reproduction velocity signal applied from reproducing
 section 160. Spindle motor driver 152 generates a driving signal to
 spindle motor 153 in response to the rotation velocity signal from
 rotation velocity controller 151. Spindle motor 153 rotates optical disc D
 in response to the driving signal.
 Reproducing section 160 reproduces the program data recorded on optical
 disc D in response to the reproduction velocity control signal from
 velocity controller 140. Also, reproducing section 160 provides the
 present reproduction velocity signal which represents the
 presently-reproduced velocity of the program data from optical disc D to
 rotation velocity controller 151.
 Table. 1 described below represents the rotation and reproduction velocity
 of the optical disc corresponding to the respective multiple velocities
 when the program data of the optical disc is reproduced at the multiple
 velocity. A case where the program data recorded on the optical disc is
 reproduced at a twice velocity is illustrated as an example.
 TABLE 1
 constant
 step linear velocity reproduction velocity
 normal reproduction R1 P1
 twice velocity reproduction R2 P2
 three times velocity R3 P3
 reproduction
 . . .
 . . .
 . . .
 N times velocity RN PN
 reproduction
 When a reproduction signal corresponding to the twice velocity from key
 inputting section 100 is inputted by the user's key operation,
 maincontroller 120 reads out rotation velocity information R2 and
 reproduction velocity information P2 of optical disc D corresponding to
 the reproduction signal indicating the twice velocity from storing section
 110 as shown in Table. 1.
 Main-controller 120, based on read-out rotation velocity information R2 and
 reproduction velocity information P2, applies rotation and reproduction
 velocity information signals of the twice velocity for reproducing the
 program data recorded on optical disc D at the twice velocity to velocity
 controller 140.
 Velocity controller 140, based on the rotation and reproduction velocity
 information signals from maincontroller 120, divides the reference clock
 signal inputted from clock generator 130 to provide rotation and
 reproduction velocity control signals corresponding to the twice velocity
 and a memory control signal corresponding to the twice velocity to
 rotation velocity controller 151, reproducing section 160, and memory 170,
 respectively.
 Rotation velocity controller 151 outputs the rotation velocity signal
 indicating the twice velocity in response to the rotation velocity control
 signal of the twice velocity inputted from velocity controller 140. At
 this time, the rotation velocity signal indicating the twice velocity is
 variably outputted according to the present reproduction velocity signal
 applied from reproducing section 160. That is, when the reproduction
 velocity of reproducing section 160 is either slower or faster than the
 rotation velocity of optical disc D, rotation velocity controller 151
 variably controls the clock period of the rotation velocity signal
 according to the reproduction velocity.
 Spindle motor driver 152 generates a driving signal indicating the twice
 velocity to spindle motor 153 in response to the rotation velocity signal
 indicating the twice velocity from rotation velocity controller 151.
 Spindle motor 153 rotates optical disc D at the twice rotation velocity
 which is faster than a normal rotation velocity in response to the driving
 signal of the twice velocity from spindle motor driver 152. Accordingly,
 optical disc D rotates at the twice rotation velocity which is faster than
 the normal rotation velocity.
 Reproducing section 160, responsive to the reproduction velocity control
 signal indicating the twice velocity from velocity controller 140,
 reproduces the program data recorded on optical disc D at the twice
 reproduction velocity which is faster than a normal reproduction velocity.
 That is, every I picture included into the program data from optical disc D
 rotating at the twice velocity is sequentially read out at a velocity
 which is identical with the rotation velocity by reproducing section 160.
 Also, reproducing section 160 sequentially provides memory 170 with the
 reproduced program data having the I pictures in order to process the
 reproduced program data at the twice velocity without a loss of the
 program data.
 In addition, reproducing section 160 applies the present reproduction
 velocity signal which represents the presently-reproduced velocity of the
 program data from optical disc D to rotation velocity controller 151.
 Memory 170 sequentially stores the program data inputted from reproducing
 section 160 and sequentially outputs the stored program data in response
 to the memory control signal from velocity controller 140. At this time,
 memory 170 has at least two memory fields. When the program data from
 reproducing section 160 is stored in a first memory field, memory 170
 reads out the program data which is stored in a second memory field and
 outputs the read out program data according to the control of reproducing
 section 160 and velocity controller 140.
 The reproducing operation described above is identically executed when the
 user reproduces the program data recorded on optical disc D at a constant
 linear velocity, three times velocity, or four times velocity. That is,
 when the reproduction signal generated by the user's key operation is a
 reproduction signal corresponding to N times velocity, velocity controller
 140 outputs rotation and reproduction velocity control signals indicating
 the N times velocity.
 In the apparatus for reproducing program data recorded on the optical disc
 at the multiple velocity according to the present invention, the rotation
 velocity of optical disc D and the reproduction velocity of the program
 data recorded on optical disc D are variably controlled in accordance with
 the user's key operation. Also, the program data reproduced at the
 multiple velocity is outputted to a display apparatus after the program
 data is sequentially stored in the memory. Accordingly, the loss of the
 program data which is reproduced from optical disc D does not occur even
 though the user selects a mode for reproducing the program data recorded
 on optical disc D at the multiple velocity. Therefore, the apparatus can
 prevent the deterioration of the screen quality caused by reproducing the
 program data recorded on optical disc D at the multiple velocity.
 While the present invention has been particularly shown and described with
 reference to a particular embodiment thereof, it will be understood by
 those skilled in the art that various changes in form and details may be
 effected therein without departing from the spirit and scope of the
 invention as defined by the appended claims.